WorldWideScience

Sample records for groundwater recharge systems

  1. Emulation of recharge and evapotranspiration processes in shallow groundwater systems

    Science.gov (United States)

    Doble, Rebecca C.; Pickett, Trevor; Crosbie, Russell S.; Morgan, Leanne K.; Turnadge, Chris; Davies, Phil J.

    2017-12-01

    In shallow groundwater systems, recharge and evapotranspiration are highly sensitive to changes in the depth to water table. To effectively model these fluxes, complex functions that include soil and vegetation properties are often required. Model emulation (surrogate modelling or meta-modelling) can provide a means of incorporating detailed conceptualisation of recharge and evapotranspiration processes, while maintaining the numerical tractability and computational performance required for regional scale groundwater models and uncertainty analysis. A method for emulating recharge and evapotranspiration processes in groundwater flow models was developed, and applied to the South East region of South Australia and western Victoria, which is characterised by shallow groundwater, wetlands and coastal lakes. The soil-vegetation-atmosphere transfer (SVAT) model WAVES was used to generate relationships between net recharge (diffuse recharge minus evapotranspiration from groundwater) and depth to water table for different combinations of climate, soil and land cover types. These relationships, which mimicked previously described soil, vegetation and groundwater behaviour, were combined into a net recharge lookup table. The segmented evapotranspiration package in MODFLOW was adapted to select values of net recharge from the lookup table depending on groundwater depth, and the climate, soil and land use characteristics of each cell. The model was found to be numerically robust in steady state testing, had no major increase in run time, and would be more efficient than tightly-coupled modelling approaches. It made reasonable predictions of net recharge and groundwater head compared with remotely sensed estimates of net recharge and a standard MODFLOW comparison model. In particular, the method was better able to predict net recharge and groundwater head in areas with steep hydraulic gradients.

  2. Groundwater recharge: The intersection between humanity and hydrogeology

    Science.gov (United States)

    Smerdon, Brian D.; Drewes, Jörg E.

    2017-12-01

    Groundwater recharge is an essential part of subsurface water circulation and the beginning of groundwater flow systems that can vary in duration from days to millennia. Globally, there is a growing body of evidence suggesting that many of Earth's aquifers contain 'fossil' groundwater that was recharged more than 12,000 years ago (Jasechko et al., 2017), and a very small portion of groundwater that was recharged within the last 50 years (Gleeson et al., 2015). Together, this information demonstrates the irregular distribution of groundwater circulation within the Earth and the wide variability of recharge conditions that replenish aquifer systems (Befus et al., 2017). Knowledge of groundwater recharge rates and distribution are needed for evaluating and regulating the quantity and quality of water resources, understanding consequences of landscapes use, identifying where managed aquifer recharge can augment supply, and predicting how groundwater systems will respond to a changing climate. In-turn, these topics are of central importance for the health of humans and ecosystems, and security of food and energy. Yet, despite the global importance, quantifying groundwater recharge remains challenging as it cannot be measured directly, and there is uncertainty associated with all currently known estimation methods (Scanlon et al., 2002).

  3. Quantification of groundwater recharge in urban environments.

    Science.gov (United States)

    Tubau, Isabel; Vázquez-Suñé, Enric; Carrera, Jesús; Valhondo, Cristina; Criollo, Rotman

    2017-08-15

    Groundwater management in urban areas requires a detailed knowledge of the hydrogeological system as well as the adequate tools for predicting the amount of groundwater and water quality evolution. In that context, a key difference between urban and natural areas lies in recharge evaluation. A large number of studies have been published since the 1990s that evaluate recharge in urban areas, with no specific methodology. Most of these methods show that there are generally higher rates of recharge in urban settings than in natural settings. Methods such as mixing ratios or groundwater modeling can be used to better estimate the relative importance of different sources of recharge and may prove to be a good tool for total recharge evaluation. However, accurate evaluation of this input is difficult. The objective is to present a methodology to help overcome those difficulties, and which will allow us to quantify the variability in space and time of the recharge into aquifers in urban areas. Recharge calculations have been initially performed by defining and applying some analytical equations, and validation has been assessed based on groundwater flow and solute transport modeling. This methodology is applicable to complex systems by considering temporal variability of all water sources. This allows managers of urban groundwater to evaluate the relative contribution of different recharge sources at a city scale by considering quantity and quality factors. The methodology is applied to the assessment of recharge sources in the Barcelona city aquifers. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Fate of human viruses in groundwater recharge systems

    Energy Technology Data Exchange (ETDEWEB)

    Vaughn, J.M.; Landry, E.F.

    1980-03-01

    The overall objective of this research program was to determine the ability of a well-managed tertiary effluent-recharge system to return virologically acceptable water to the groundwater aquifer. The study assessed the quality of waters renovated by indigenous recharge operations and investigated a number of virus-soil interrelationships. The elucidation of the interactions led to the establishment of basin operating criteria for optimizing virus removal. Raw influents, chlorinated tertiary effluents, and renovated wastewater from the aquifer directly beneath a uniquely designed recharge test basin were assayed on a weekly basis for the presence of human enteroviruses and coliform bacteria. High concentrations of viruses were routinely isolated from influents but were isolated only on four occasions from tertiary-treated sewage effluents. In spite of the high quality effluent being recharged, viruses were isolated from the groundwater observation well, indicating their ability to penetrate the unsaturated zone. Results of poliovirus seeding experiments carried out in the test basin clearly indicated the need to operate recharge basins at low (e.g. 1 cm/h) infiltration rates in areas having soil types similar to those found at the study site. The method selected for reducing the test basin infiltration rate involved clogging the basin surface with settled organic material from highly turbid effluent. Alternative methods for slowing infiltration rates are discussed in the text.

  5. Precipitation Intensity Effects on Groundwater Recharge in the Southwestern United States

    Directory of Open Access Journals (Sweden)

    Brian F. Thomas

    2016-03-01

    Full Text Available Episodic recharge as a result of infrequent, high intensity precipitation events comprises the bulk of groundwater recharge in arid environments. Climate change and shifts in precipitation intensity will affect groundwater continuity, thus altering groundwater recharge. This study aims to identify changes in the ratio of groundwater recharge and precipitation, the R:P ratio, in the arid southwestern United States to characterize observed changes in groundwater recharge attributed to variations in precipitation intensity. Our precipitation metric, precipitation intensity magnification, was used to investigate the relationship between the R:P ratio and precipitation intensity. Our analysis identified significant changes in the R:P ratio concurrent with decreases in precipitation intensity. The results illustrate the importance of precipitation intensity in relation to groundwater recharge in arid regions and provide further insights for groundwater management in nonrenewable groundwater systems and in a changing climate.

  6. NORTH CAROLINA GROUNDWATER RECHARGE RATES 1994

    Science.gov (United States)

    North Carolina Groundwater Recharge Rates, from Heath, R.C., 1994, Ground-water recharge in North Carolina: North Carolina State University, as prepared for the NC Department of Environment, Health and Natural Resources (NC DEHNR) Division of Enviromental Management Groundwater S...

  7. Using groundwater levels to estimate recharge

    Science.gov (United States)

    Healy, R.W.; Cook, P.G.

    2002-01-01

    Accurate estimation of groundwater recharge is extremely important for proper management of groundwater systems. Many different approaches exist for estimating recharge. This paper presents a review of methods that are based on groundwater-level data. The water-table fluctuation method may be the most widely used technique for estimating recharge; it requires knowledge of specific yield and changes in water levels over time. Advantages of this approach include its simplicity and an insensitivity to the mechanism by which water moves through the unsaturated zone. Uncertainty in estimates generated by this method relate to the limited accuracy with which specific yield can be determined and to the extent to which assumptions inherent in the method are valid. Other methods that use water levels (mostly based on the Darcy equation) are also described. The theory underlying the methods is explained. Examples from the literature are used to illustrate applications of the different methods.

  8. California GAMA Special Study: Importance of River Water Recharge to Selected Groundwater Basins

    Energy Technology Data Exchange (ETDEWEB)

    Visser, Ate [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Moran, Jean E. [California State Univ. East Bay (CalState), Hayward, CA (United States); Singleton, Michael J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Esser, Bradley K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-03-21

    River recharge represents 63%, 86% and 46% of modern groundwater in the Mojave Desert, Owens Valley, and San Joaquin Valley, respectively. In pre-modern groundwater, river recharge represents a lower fraction: 36%, 46%, and 24% respectively. The importance of river water recharge in the San Joaquin valley has nearly doubled and is likely the result of a total increase of recharge of 40%, caused by river water irrigation return flows. This emphasizes the importance of recharge of river water via irrigation for renewal of groundwater resources. Mountain front recharge and local precipitation contribute to recharge of desert groundwater basins in part as the result of geological features focusing scarce precipitation promoting infiltration. River water recharges groundwater systems under lower temperatures and with larger water table fluctuations than local precipitation recharge. Surface storage is limited in time and volume, as evidenced by cold river recharge temperatures resulting from fast recharge, compared to the large capacity for subsurface storage. Groundwater banking of seasonal surface water flows therefore appears to be a natural and promising method for increasing the resilience of water supply systems. The distinct isotopic and noble gas signatures of river water recharge, compared to local precipitation recharge, reflecting the source and mechanism of recharge, are valuable constraints for numerical flow models.

  9. Assessment of groundwater recharge and water fluxes of the Guarani Aquifer System, Brazil

    Science.gov (United States)

    Rabelo, Jorge Luiz; Wendland, Edson

    2009-11-01

    The groundwater recharge and water fluxes of the Guarani Aquifer System in the state of Sao Paulo in Brazil were assessed through a numeric model. The study area (6,748 km2) comprises Jacaré-Guaçú and Jacaré-Pepira River watersheds, tributaries of the Tietê River in the central region of the state. GIS based tools were used in the storage, processing and analysis of data. Main hydrologic phenomena were selected, leading to a groundwater conceptual model, taking into account the significant outcrops occurring in the study area. Six recharge zones were related to the geologic formation and structures of the semi-confined and phreatic aquifer. The model was calibrated against the baseflows and static water levels of the wells. The results emphasize the strong interaction of groundwater flows between watersheds and the groundwater inflow into the rivers. It has been concluded that lateral groundwater exchanges between basins, the deep discharges to the regional system, and well exploitation were not significant aquifer outflows when compared to the aquifer recharge. The results have shown that the inflows from the river into the aquifer are significant and have the utmost importance since the aquifer is potentially more vulnerable in these places.

  10. Artificial groundwater recharge as integral part of a water resources system in a humid environment

    Science.gov (United States)

    Kupfersberger, Hans; Stadler, Hermann

    2010-05-01

    In Graz, Austria, artificial groundwater recharge has been operated as an integral part of the drinking water supply system for more than thirty years. About 180 l/s of high quality water from pristine creeks (i.e. no pre-treatment necessary) are infiltrated via sand and lawn basins and infiltration trenches into two phreatic aquifers to sustain the extraction of approximately 400 l/s. The remaining third of drinking water for roughly 300.000 people is provided by a remote supply line from the East alpine karst region Hochschwab. By this threefold model the water supply system is less vulnerable to external conditions. In the early 1980's the infiltration devices were also designed as a hydraulic barrier against riverbank infiltration from the river Mur, which at that time showed seriously impaired water quality due to upstream paper mills. This resulted into high iron and manganese groundwater concentrations which lead to clogging of the pumping wells. These problems have been eliminated in the meantime due to the onsite purification of paper mill effluents and the construction of many waste water treatment plants. The recharge system has recently been thoroughly examined to optimize the operation of groundwater recharge and to provide a basis for further extension. The investigations included (i) field experiments and laboratory analyses to improve the trade off between infiltration rate and elimination capacities of the sand filter basins' top layer, (ii) numerical groundwater modelling to compute the recovery rate of the recharged water, the composition of the origin of the pumped water, emergency scenarios due to the failure of system parts, the transient capture zones of the withdrawal wells and the coordination of recharge and withdrawal and (iii) development of an online monitoring setup combined with a decision support system to guarantee reliable functioning of the entire structure. Additionally, the depreciation, maintenance and operation costs of the

  11. Comparing groundwater recharge and base flow in the Bukmoongol ...

    Indian Academy of Sciences (India)

    Groundwater recharge and base flow using different investigated methods are simulated in the 15-ha Bukmoongol small-forested watershed located at the southern part of Korea.The WHAT system, PART,RORA,PULSE,BFI,and RAP software are used to estimate groundwater recharge or base flow and base flow index from ...

  12. Ground-water recharge in Fortymile Wash near Yucca Mountain, Nevada, 1992--1993

    International Nuclear Information System (INIS)

    Savard, C.S.

    1994-01-01

    Quantification of the ground-water recharge from streamflow in the Fortymile Wash watershed will contribute to regional ground-water studies. Regional ground-water studies are an important component in the studies evaluating the ground-water flow system as a barrier to the potential migration of radionuclides from the potential underground high-level nuclear waste repository. Knowledge gained in understanding the ground-water recharge mechanisms and pathways in the Pah Canyon area, which is 10 km to the northeast of Yucca Mountain, may transfer to Yucca site specific studies. The current data collection network in Fortymile Canyon does not permit quantification of ground-water recharge, however a qualitative understanding of ground-water recharge was developed from these data

  13. Estimating the proportion of groundwater recharge from flood events in relation to total annual recharge in a karst aquifer

    Science.gov (United States)

    Dvory, N. Z.; Ronen, A.; Livshitz, Y.; Adar, E.; Kuznetsov, M.; Yakirevich, A.

    2017-12-01

    Sustainable groundwater production from karstic aquifers is primarily dictated by its recharge rate. Therefore, in order to limit over-exploitation, it is essential to accurately quantify groundwater recharge. Infiltration during erratic floods in karstic basins may contribute substantial amount to aquifer recharge. However, the complicated nature of karst systems, which are characterized in part by multiple springs, sinkholes, and losing/gaining streams, present a large obstacle to accurately assess the actual contribution of flood water to groundwater recharge. In this study, we aim to quantify the proportion of groundwater recharge during flood events in relation to the annual recharge for karst aquifers. The role of karst conduits on flash flood infiltration was examined during four flood and artificial runoff events in the Sorek creek near Jerusalem, Israel. The events were monitored in short time steps (four minutes). This high resolution analysis is essential to accurately estimating surface flow volumes, which are of particular importance in arid and semi-arid climate where ephemeral flows may provide a substantial contribution to the groundwater reservoirs. For the present investigation, we distinguished between direct infiltration, percolation through karst conduits and diffused infiltration, which is most affected by evapotranspiration. A water balance was then calculated for the 2014/15 hydrologic year using the Hydrologic Engineering Center - Hydrologic Modelling System (HEC-HMS). Simulations show that an additional 8% to 24% of the annual recharge volume is added from runoff losses along the creek that infiltrate through the karst system into the aquifer. The results improve the understanding of recharge processes and support the use of the proposed methodology for quantifying groundwater recharge.

  14. Recharge Area of Groundwater of Jakarta Basin

    International Nuclear Information System (INIS)

    Wandowo; Abidin, Zainal; Alip; Djiono

    2002-01-01

    Groundwater inside the earth contained in a porous and permeable layers called aquifers. Depend on the hydrogeological structure, the aquifers may be composed of independent layers separated each other by impermeable boundaries. Such a condition may effect the location of recharge where water is able to infiltrate and goes to the aquifers. The objective of this research is to find out and to locate the recharge area of Jakarta basin by utilizing stable isotopes 2H and 18O . The work was done by collecting shallow and deep groundwater samples throughout Jabotabek area and precipitations from different altitudes. Since the stable isotopes composition of precipitation is subject to the altitude, the recharge area would be able to be identified by assessing the correlation of stable isotopes composition of precipitation and corresponding groundwater population. The data obtained from this study suggested that shallow groundwater is originated from local recharge while deep groundwater is recharged from the area having altitude of 125 -230 meters, it correspond to the area between Depok and Bogor

  15. Global synthesis of groundwater recharge in semiarid and arid regions

    Science.gov (United States)

    Scanlon, Bridget R.; Keese, K.E.; Flint, A.L.; Flint, L.E.; Gaye, C.B.; Edmunds, W.M.; Simmers, I.

    2006-01-01

    Global synthesis of the findings from ∼140 recharge study areas in semiarid and arid regions provides important information on recharge rates, controls, and processes, which are critical for sustainable water development. Water resource evaluation, dryland salinity assessment (Australia), and radioactive waste disposal (US) are among the primary goals of many of these recharge studies. The chloride mass balance (CMB) technique is widely used to estimate recharge. Average recharge rates estimated over large areas (40–374 000 km2) range from 0·2 to 35 mm year−1, representing 0·1–5% of long-term average annual precipitation. Extreme local variability in recharge, with rates up to ∼720 m year−1, results from focussed recharge beneath ephemeral streams and lakes and preferential flow mostly in fractured systems. System response to climate variability and land use/land cover (LU/LC) changes is archived in unsaturated zone tracer profiles and in groundwater level fluctuations. Inter-annual climate variability related to El Niño Southern Oscillation (ENSO) results in up to three times higher recharge in regions within the SW US during periods of frequent El Niños (1977–1998) relative to periods dominated by La Niñas (1941–1957). Enhanced recharge related to ENSO is also documented in Argentina. Climate variability at decadal to century scales recorded in chloride profiles in Africa results in recharge rates of 30 mm year−1 during the Sahel drought (1970–1986) to 150 mm year−1 during non-drought periods. Variations in climate at millennial scales in the SW US changed systems from recharge during the Pleistocene glacial period (≥10 000 years ago) to discharge during the Holocene semiarid period. LU/LC changes such as deforestation in Australia increased recharge up to about 2 orders of magnitude. Changes from natural grassland and shrublands to dryland (rain-fed) agriculture altered systems from discharge (evapotranspiration, ET) to recharge in

  16. Effect of irrigation return flow on groundwater recharge in an overexploited aquifer in Bangladesh

    Science.gov (United States)

    Touhidul Mustafa, Syed Md.; Shamsudduha, Mohammad; Huysmans, Marijke

    2016-04-01

    Irrigated agriculture has an important role in the food production to ensure food security of Bangladesh that is home to over 150 million people. However, overexploitation of groundwater for irrigation, particularly during the dry season, causes groundwater-level decline in areas where abstraction is high and surface geology inhibits direct recharge to underlying shallow aquifer. This is causing a number of potential adverse socio-economic, hydrogeological, and environmental problems in Bangladesh. Alluvial aquifers are primarily recharged during monsoon season from rainfall and surface sources. However, return flow from groundwater-fed irrigation can recharge during the dry months. Quantification of the effect of return flow from irrigation in the groundwater system is currently unclear but thought to be important to ensure sustainable management of the overexploited aquifer. The objective of the study is to investigate the effect of irrigation return flow on groundwater recharge in the north-western part of Bangladesh, also known as Barind Tract. A semi-physically based distributed water balance model (WetSpass-M) is used to simulate spatially distributed monthly groundwater recharge. Results show that, groundwater abstraction for irrigation in the study area has increased steadily over the last 29 years. During the monsoon season, local precipitation is the controlling factor of groundwater recharge; however, there is no trend in groundwater recharge during that period. During the dry season, however, irrigation return-flow plays a major role in recharging the aquifer in the irrigated area compared to local precipitation. Therefore, during the dry season, mean seasonal groundwater recharge has increased and almost doubled over the last 29 years as a result of increased abstraction for irrigation. The increase in groundwater recharge during dry season has however no significant effect in the improvement of groundwater levels. The relation between groundwater

  17. Dug Well Recharge Method for Insitu Mitigation of Fluoride Contamination in Groundwater

    Science.gov (United States)

    Ganesan, G.; Lakshmanan, E.; Gunalan, J.

    2016-12-01

    Groundwater with fluoride concentration exceeding 1.5 mg/l is not suitable for drinking water supply as it may cause health issues such as dental and skeletal fluorosis to humans. Several million people around the world has been affected by fluorosis. The objective of the study is to mitigate the problem of fluoride contamination in groundwater by increasing groundwater recharge through a dug well recharge system. The study was carried out in a part of Vaniyar river basin, northwest Tamil Nadu, India where fluorosis is prevalent. A cylindrical pit of 1m diameter and 1.5 m height was constructed during May 2014 at a distance of about 4 m from a dug well existing in this area. This cylindrical pit was divided into 3 compartments and one of them was filled with gravel and one with sand. The third compartment was kept empty for inspection and maintenance. The rainfall collected in a funnel shaped depression was allowed to pass through these compartments to discharge in the nearby dug well through a pipe. The concentration of the fluoride in groundwater from this well was had been monitoring on bi-monthly basis from the year 2012 to 2014. After construction of dug well recharge system, the groundwater level has raised by about 5 m and the fluoride concentration has decreased from 3.1 mg/l to 1.44 mg/l due to recharge. The concentration of fluoride and groundwater level is being monitored on daily basis from June 2014. It is evident that the recharge system constructed is working well and the concentration of fluoride in groundwater is within the permissible limit. The advantage of this dug well recharge system is its low cost and the ease of implementation. Thus this pilot study on dug well recharge system demonstrated it's potential in reducing the concentration of fluoride in groundwater which is more beneficial to the society as they cannot afford the well proven water treatment methods.

  18. Summary of groundwater-recharge estimates for Pennsylvania

    Science.gov (United States)

    Stuart O. Reese,; Risser, Dennis W.

    2010-01-01

    Groundwater recharge is water that infiltrates through the subsurface to the zone of saturation beneath the water table. Because recharge is a difficult parameter to quantify, it is typically estimated from measurements of other parameters like streamflow and precipitation. This report provides a general overview of processes affecting recharge in Pennsylvania and presents estimates of recharge rates from studies at various scales.The most common method for estimating recharge in Pennsylvania has been to estimate base flow from measurements of streamflow and assume that base flow (expressed in inches over the basin) approximates recharge. Statewide estimates of mean annual groundwater recharge were developed by relating base flow to basin characteristics of HUC10 watersheds (a fifth-level classification that uses 10 digits to define unique hydrologic units) using a regression equation. The regression analysis indicated that mean annual precipitation, average daily maximum temperature, percent of sand in soil, percent of carbonate rock in the watershed, and average stream-channel slope were significant factors in the explaining the variability of groundwater recharge across the Commonwealth.Several maps are included in this report to illustrate the principal factors affecting recharge and provide additional information about the spatial distribution of recharge in Pennsylvania. The maps portray the patterns of precipitation, temperature, prevailing winds across Pennsylvania’s varied physiography; illustrate the error associated with recharge estimates; and show the spatial variability of recharge as a percent of precipitation. National, statewide, regional, and local values of recharge, based on numerous studies, are compiled to allow comparison of estimates from various sources. Together these plates provide a synopsis of groundwater-recharge estimations and factors in Pennsylvania.Areas that receive the most recharge are typically those that get the most

  19. Recharge signal identification based on groundwater level observations.

    Science.gov (United States)

    Yu, Hwa-Lung; Chu, Hone-Jay

    2012-10-01

    This study applied a method of the rotated empirical orthogonal functions to directly decompose the space-time groundwater level variations and determine the potential recharge zones by investigating the correlation between the identified groundwater signals and the observed local rainfall records. The approach is used to analyze the spatiotemporal process of piezometric heads estimated by Bayesian maximum entropy method from monthly observations of 45 wells in 1999-2007 located in the Pingtung Plain of Taiwan. From the results, the primary potential recharge area is located at the proximal fan areas where the recharge process accounts for 88% of the spatiotemporal variations of piezometric heads in the study area. The decomposition of groundwater levels associated with rainfall can provide information on the recharge process since rainfall is an important contributor to groundwater recharge in semi-arid regions. Correlation analysis shows that the identified recharge closely associates with the temporal variation of the local precipitation with a delay of 1-2 months in the study area.

  20. Physical Experiment and Numerical Simulation of the Artificial Recharge Effect on Groundwater Reservoir

    Directory of Open Access Journals (Sweden)

    Yang Xu

    2017-11-01

    Full Text Available To improve the efficiency of utilizing water resources in arid areas, the mechanism of artificial recharge effecting on groundwater reservoir was analyzed in this research. Based on a generalized groundwater reservoir in a two-dimensional sand tank model, different scenarios of the infiltration basin location and recharge intensity are designed to study how to improve the efficiency of groundwater reservoir artificial recharge. The effective storage capacity and the effective storage rate are taken as the main parameters to analyze the relation between recharge water volume and storage capacity. By combining with groundwater flow system theory, FEFLOW (Finite Element subsurface FLOW system is adopted to set up the groundwater numerical model. It is used to verify the experiment results and to make deep analysis on the rule of water table fluctuations and groundwater movement in the aquifer. Based on the model, different scenarios are designed to examine the combined effect of recharge intensity and intermittent periods. The research results show that: the distance between infiltration basin and pumping well should be shortened appropriately, but not too close; increasing recharge intensity helps to enlarge the effective storage capacity, but it can also reduce the effective storage rate, which goes against the purpose of effective utilization of water resources; and, the recharge intensity and recharge duration should be given full consideration by the actual requirements when we take the approach of intermittent recharge to make a reasonable choice.

  1. Predicting groundwater recharge for varying land cover and climate conditions - a global meta-study

    Science.gov (United States)

    Mohan, Chinchu; Western, Andrew W.; Wei, Yongping; Saft, Margarita

    2018-05-01

    Groundwater recharge is one of the important factors determining the groundwater development potential of an area. Even though recharge plays a key role in controlling groundwater system dynamics, much uncertainty remains regarding the relationships between groundwater recharge and its governing factors at a large scale. Therefore, this study aims to identify the most influential factors of groundwater recharge, and to develop an empirical model to estimate diffuse rainfall recharge at a global scale. Recharge estimates reported in the literature from various parts of the world (715 sites) were compiled and used in model building and testing exercises. Unlike conventional recharge estimates from water balance, this study used a multimodel inference approach and information theory to explain the relationship between groundwater recharge and influential factors, and to predict groundwater recharge at 0.5° resolution. The results show that meteorological factors (precipitation and potential evapotranspiration) and vegetation factors (land use and land cover) had the most predictive power for recharge. According to the model, long-term global average annual recharge (1981-2014) was 134 mm yr-1 with a prediction error ranging from -8 to 10 mm yr-1 for 97.2 % of cases. The recharge estimates presented in this study are unique and more reliable than the existing global groundwater recharge estimates because of the extensive validation carried out using both independent local estimates collated from the literature and national statistics from the Food and Agriculture Organization (FAO). In a water-scarce future driven by increased anthropogenic development, the results from this study will aid in making informed decisions about groundwater potential at a large scale.

  2. Groundwater recharge and agricultural contamination

    Science.gov (United States)

    Böhlke, J.K.

    2002-01-01

    Agriculture has had direct and indirect effects on the rates and compositions of groundwater recharge and aquifer biogeochemistry. Direct effects include dissolution and transport of excess quantities of fertilizers and associated materials and hydrologic alterations related to irrigation and drainage. Some indirect effects include changes in water–rock reactions in soils and aquifers caused by increased concentrations of dissolved oxidants, protons, and major ions. Agricultural activities have directly or indirectly affected the concentrations of a large number of inorganic chemicals in groundwater, for example NO3–, N2, Cl, SO42–, H+, P, C, K, Mg, Ca, Sr, Ba, Ra, and As, as well as a wide variety of pesticides and other organic compounds. For reactive contaminants like NO3–, a combination of chemical, isotopic, and environmental-tracer analytical approaches might be required to resolve changing inputs from subsequent alterations as causes of concentration gradients in groundwater. Groundwater records derived from multi-component hydrostratigraphic data can be used to quantify recharge rates and residence times of water and dissolved contaminants, document past variations in recharging contaminant loads, and identify natural contaminant-remediation processes. These data indicate that many of the world's surficial aquifers contain transient records of changing agricultural contamination from the last half of the 20th century. The transient agricultural groundwater signal has important implications for long-term trends and spatial heterogeneity in discharge.

  3. Estimation of groundwater recharge in sedimentary rock aquifer systems in the Oti basin of Gushiegu District, Northern Ghana

    Science.gov (United States)

    Afrifa, George Yamoah; Sakyi, Patrick Asamoah; Chegbeleh, Larry Pax

    2017-07-01

    Sustainable development and the management of groundwater resources for optimal socio-economic development constitutes one of the most effective strategies for mitigating the effects of climate change in rural areas where poverty is a critical cause of environmental damage. This research assessed groundwater recharge and its spatial and temporal variations in Gushiegu District in the Northern Region of Ghana, where groundwater is the main source of water supply for most uses. Isotopic data of precipitation and groundwater were used to infer the origin of groundwater and the possible relationship between groundwater and surface water in the partially metamorphosed sedimentary aquifer system in the study area. Though the data do not significantly establish strong relation between groundwater and surface water, the study suggests that groundwater in the area is of meteoric origin. However, the data also indicate significant enrichment of the heavy isotopes (18O and 2H) in groundwater relative to rainwater in the area. The Chloride Mass Balance (CMB) and Water Table Fluctuations (WTF) techniques were used to quantitatively estimate the groundwater recharge in the area. The results suggest groundwater recharge in a range of 13.9 mm/y - 218 mm/y, with an average of 89 mm/yr, representing about 1.4%-21.8% (average 8.9%) of the annual precipitation in the area. There is no clearly defined trend in the temporal variations of groundwater recharge in the area, but the spatial variations are discussed in relation to the underlying lithologies. The results suggest that the fraction of precipitation that reaches the saturated zone as groundwater recharge is largely controlled by the vertical hydraulic conductivities of the material of the unsaturated zone. The vertical hydraulic conductivity coupled with humidity variations in the area modulates the vertical infiltration and percolation of precipitation.

  4. Mitigation of non-point source of fluoride on groundwater by dug well recharge

    Science.gov (United States)

    Ganesan, G.; Lakshmanan, E.

    2017-12-01

    Groundwater used for drinking purpose is affected in many regions due to the presence of excess fluoride. The excess intake of fluoride through drinking water causes fluorosis to human in many states of India, including Tamil Nadu. The present study was carried out with the objective of assessing hydrogeochemistry of groundwater and the feasibility of dug well recharge to reduce the fluoride concentration in Vaniyar river basin, Tamil Nadu, India. The major source for fluoride in groundwater of this area is the epidote hornblende gneissic and charnockite which are the major rocks occurring in this region. As a pilot study a cost effective induced recharge structure was constructed at Papichettipatty village in the study region. The study shows that the groundwater level around the recharge site raised up to 2 m from 14.5 m (bgl) and fluoride concentration has decreased from 3.8 mg/l to 0.9 mg/l due to dilution. The advantage of this induced recharge structure is of its low cost, the ease of implementation, improved groundwater recharge and dilution of fluoride in groundwater. An area of about 1.5 km2 has benefited due to this dug well recharge system.

  5. Groundwater recharge and sustainability in the High Plains aquifer in Kansas, USA

    Science.gov (United States)

    Sophocleous, M.

    2005-01-01

    Sustainable use of groundwater must ensure not only that the future resource is not threatened by overuse, but also that natural environments that depend on the resource, such as stream baseflows, riparian vegetation, aquatic ecosystems, and wetlands are protected. To properly manage groundwater resources, accurate information about the inputs (recharge) and outputs (pumpage and natural discharge) within each groundwater basin is needed so that the long-term behavior of the aquifer and its sustainable yield can be estimated or reassessed. As a first step towards this effort, this work highlights some key groundwater recharge studies in the Kansas High Plains at different scales, such as regional soil-water budget and groundwater modeling studies, county-scale groundwater recharge studies, as well as field-experimental local studies, including some original new findings, with an emphasis on assumptions and limitations as well as on environmental factors affecting recharge processes. The general impact of irrigation and cultivation on recharge is to appreciably increase the amount of recharge, and in many cases to exceed precipitation as the predominant source of recharge. The imbalance between the water input (recharge) to the High Plains aquifer and the output (pumpage and stream baseflows primarily) is shown to be severe, and responses to stabilize the system by reducing water use, increasing irrigation efficiency, adopting water-saving land-use practices, and other measures are outlined. Finally, the basic steps necessary to move towards sustainable use of groundwater in the High Plains are delineated, such as improving the knowledge base, reporting and providing access to information, furthering public education, as well as promoting better understanding of the public's attitudinal motivations; adopting the ecosystem and adaptive management approaches to managing groundwater; further improving water efficiency; exploiting the full potential of dryland and

  6. Study of groundwater recharge in Rechna Doab using isotope techniques

    International Nuclear Information System (INIS)

    Sajjad, M.I.; Tasneem, M.A.; Ahmed, M.; Hussain, S.D.; Khan, I.H.; Akram, W.

    1992-04-01

    Isotopic studies were performed in the Rechna Doab area to understand the recharge mechanism, investigate the relative contributions from various sources such as rainfall, rivers and canal system and to estimate the turn over times and replenishment rate of groundwater. The isotopic data suggest that the groundwater in the project area can be divided into different zones each having its own characteristic isotopic composition. The enriched isotopic values show rain recharge and depleted isotopic values are associated with river/canal system while the intermediate isotopic values show a mixing of two or more sources of water. The major contribution, however, comes from canal system. The isotopic data suggest that there is no quick movement of groundwater in the area. 18 figs. (author)

  7. Management decision of optimal recharge water in groundwater artificial recharge conditions- A case study in an artificial recharge test site

    Science.gov (United States)

    He, H. Y.; Shi, X. F.; Zhu, W.; Wang, C. Q.; Ma, H. W.; Zhang, W. J.

    2017-11-01

    The city conducted groundwater artificial recharge test which was taken a typical site as an example, and the purpose is to prevent and control land subsidence, increase the amount of groundwater resources. To protect groundwater environmental quality and safety, the city chose tap water as recharge water, however, the high cost makes it not conducive to the optimal allocation of water resources and not suitable to popularize widely. To solve this, the city selects two major surface water of River A and B as the proposed recharge water, to explore its feasibility. According to a comprehensive analysis of the cost of recharge, the distance of the water transport, the quality of recharge water and others. Entropy weight Fuzzy Comprehensive Evaluation Method is used to prefer tap water and water of River A and B. Evaluation results show that water of River B is the optimal recharge water, if used; recharge cost will be from 0.4724/m3 to 0.3696/m3. Using Entropy weight Fuzzy Comprehensive Evaluation Method to confirm water of River B as optimal water is scientific and reasonable. The optimal water management decisions can provide technical support for the city to carry out overall groundwater artificial recharge engineering in deep aquifer.

  8. Groundwater Modelling For Recharge Estimation Using Satellite Based Evapotranspiration

    Science.gov (United States)

    Soheili, Mahmoud; (Tom) Rientjes, T. H. M.; (Christiaan) van der Tol, C.

    2017-04-01

    Groundwater movement is influenced by several factors and processes in the hydrological cycle, from which, recharge is of high relevance. Since the amount of aquifer extractable water directly relates to the recharge amount, estimation of recharge is a perquisite of groundwater resources management. Recharge is highly affected by water loss mechanisms the major of which is actual evapotranspiration (ETa). It is, therefore, essential to have detailed assessment of ETa impact on groundwater recharge. The objective of this study was to evaluate how recharge was affected when satellite-based evapotranspiration was used instead of in-situ based ETa in the Salland area, the Netherlands. The Methodology for Interactive Planning for Water Management (MIPWA) model setup which includes a groundwater model for the northern part of the Netherlands was used for recharge estimation. The Surface Energy Balance Algorithm for Land (SEBAL) based actual evapotranspiration maps from Waterschap Groot Salland were also used. Comparison of SEBAL based ETa estimates with in-situ abased estimates in the Netherlands showed that these SEBAL estimates were not reliable. As such results could not serve for calibrating root zone parameters in the CAPSIM model. The annual cumulative ETa map produced by the model showed that the maximum amount of evapotranspiration occurs in mixed forest areas in the northeast and a portion of central parts. Estimates ranged from 579 mm to a minimum of 0 mm in the highest elevated areas with woody vegetation in the southeast of the region. Variations in mean seasonal hydraulic head and groundwater level for each layer showed that the hydraulic gradient follows elevation in the Salland area from southeast (maximum) to northwest (minimum) of the region which depicts the groundwater flow direction. The mean seasonal water balance in CAPSIM part was evaluated to represent recharge estimation in the first layer. The highest recharge estimated flux was for autumn

  9. Natural vs. artificial groundwater recharge, quantification through inverse modeling

    Directory of Open Access Journals (Sweden)

    H. Hashemi

    2013-02-01

    Full Text Available Estimating the change in groundwater recharge from an introduced artificial recharge system is important in order to evaluate future water availability. This paper presents an inverse modeling approach to quantify the recharge contribution from both an ephemeral river channel and an introduced artificial recharge system based on floodwater spreading in arid Iran. The study used the MODFLOW-2000 to estimate recharge for both steady- and unsteady-state conditions. The model was calibrated and verified based on the observed hydraulic head in observation wells and model precision, uncertainty, and model sensitivity were analyzed in all modeling steps. The results showed that in a normal year without extreme events, the floodwater spreading system is the main contributor to recharge with 80% and the ephemeral river channel with 20% of total recharge in the studied area. Uncertainty analysis revealed that the river channel recharge estimation represents relatively more uncertainty in comparison to the artificial recharge zones. The model is also less sensitive to the river channel. The results show that by expanding the artificial recharge system, the recharge volume can be increased even for small flood events, while the recharge through the river channel increases only for major flood events.

  10. NTS groundwater recharge study, FY 1992

    International Nuclear Information System (INIS)

    Lyles, B.F.; Mihevc, T.M.

    1992-10-01

    Groundwater recharge from precipitation is thought by many scientists to be extremely low in Southem Nevada; however, no direct measurements of recharge have been made to substantiate this hypothesis. Three geomorphic regions have been identified as potential areas of groundwater recharge at the Nevada Test Site (NTS): mesas, washes, and lowlands. Eight recharge monitoring stations have been installed to monitor each of these regions; four of the stations are on Pahute/Rainier Mesa, two stations are in Fortymile Wash, one station is in a transition area between the mesas and the lowlands (Whiterock Spring), and one station is located in Yucca Flat at the bottom of the U-3fd crater. An additional station is proposed for Frenchman Flat near the Area 5 mixed waste facility; however, the instrumentation of that site has been delayed due to the complex permitting process associated with instrument installation near the mixed waste facility. Digital data were collected from eight sites during FY 1992

  11. Modeling of water transfer to aquifers: application to the determination of groundwater recharge by inversion in a complex hydrogeological system

    International Nuclear Information System (INIS)

    Hassane-Mamadou-Maina, Fadji-Zaouna

    2016-01-01

    Groundwater is the main available water resource for many countries; they are mainly replenished by water from precipitation, called groundwater recharge. Due to its great importance, management of groundwater resources is more essential than ever, and is achieved through mathematical models which offer us a better understanding of physical phenomena as well as their prediction. Hydrogeological Systems are generally complex thus characterized by a highly variable dynamic over time and space. These complexities have attracted the attention of many hydro geologists and many sophisticated models that can handle these issues and describe these Systems accurately were developed. Unfortunately, modeling groundwater recharge is still a challenge in groundwater resource management. Generally, groundwater models are used to simulate aquifers flow without a good estimation of recharge and its spatial-temporal distribution. as groundwater recharge rates show spatial-temporal variability due to climatic conditions, land use, and hydrogeological heterogeneity, these methods have limitations in dealing with these characteristics. To overcome these limitations, a coupled model which simulates flow in the unsaturated zone and recharge as well as groundwater flow was developed. The flow in the unsaturated zone is solved either with resolution of Richards equation or with empirical models while the diffusivity equation governs flow in the saturated zone. Robust numerical methods were used to solve these equations: we apply nonconforming finite element to solve the diffusivity equation and we used an accurate and efficient method for solving the Richards equation. In the natural environments, parameters that control these hydrological mechanisms aren't accurately known or even unknowns, only variations of piezometric heads are commonly available. Hence, ail parameters related to unsaturated and saturated flows will be identified by using only these piezometric data

  12. Statewide Groundwater Recharge Modeling in New Mexico

    Science.gov (United States)

    Xu, F.; Cadol, D.; Newton, B. T.; Phillips, F. M.

    2017-12-01

    It is crucial to understand the rate and distribution of groundwater recharge in New Mexico because it not only largely defines a limit for water availability in this semi-arid state, but also is the least understood aspect of the state's water budget. With the goal of estimating groundwater recharge statewide, we are developing the Evapotranspiration and Recharge Model (ETRM), which uses existing spatial datasets to model the daily soil water balance over the state at a resolution of 250 m cell. The input datasets includes PRISM precipitation data, MODIS Normalized Difference Vegetation Index (NDVI), NRCS soils data, state geology data and reference ET estimates produced by Gridded Atmospheric Data downscalinG and Evapotranspiration Tools (GADGET). The current estimated recharge presents diffuse recharge only, not focused recharge as in channels or playas. Direct recharge measurements are challenging and rare, therefore we estimate diffuse recharge using a water balance approach. The ETRM simulated runoff amount was compared with USGS gauged discharge in four selected ephemeral channels: Mogollon Creek, Zuni River, the Rio Puerco above Bernardo, and the Rio Puerco above Arroyo Chico. Result showed that focused recharge is important, and basin characteristics can be linked with watershed hydrological response. As the sparse instruments in NM provide limited help in improving estimation of focused recharge by linking basin characteristics, the Walnut Gulch Experimental Watershed, which is one of the most densely gauged and monitored semiarid rangeland watershed for hydrology research purpose, is now being modeled with ETRM. Higher spatial resolution of field data is expected to enable detailed comparison of model recharge results with measured transmission losses in ephemeral channels. The final ETRM product will establish an algorithm to estimate the groundwater recharge as a water budget component of the entire state of New Mexico. Reference ET estimated by GADGET

  13. Changes in groundwater recharge under projected climate in the upper Colorado River basin

    Science.gov (United States)

    Tillman, Fred; Gangopadhyay, Subhrendu; Pruitt, Tom

    2016-01-01

    Understanding groundwater-budget components, particularly groundwater recharge, is important to sustainably manage both groundwater and surface water supplies in the Colorado River basin now and in the future. This study quantifies projected changes in upper Colorado River basin (UCRB) groundwater recharge from recent historical (1950–2015) through future (2016–2099) time periods, using a distributed-parameter groundwater recharge model with downscaled climate data from 97 Coupled Model Intercomparison Project Phase 5 climate projections. Simulated future groundwater recharge in the UCRB is generally expected to be greater than the historical average in most decades. Increases in groundwater recharge in the UCRB are a consequence of projected increases in precipitation, offsetting reductions in recharge that would result from projected increased temperatures.

  14. Groundwater recharge estimation under semi arid climate: Case of Northern Gafsa watershed, Tunisia

    Science.gov (United States)

    Melki, Achraf; Abdollahi, Khodayar; Fatahi, Rouhallah; Abida, Habib

    2017-08-01

    Natural groundwater recharge under semi arid climate, like rainfall, is subjected to large variations in both time and space and is therefore very difficult to predict. Nevertheless, in order to set up any strategy for water resources management in such regions, understanding the groundwater recharge variability is essential. This work is interested in examining the impact of rainfall on the aquifer system recharge in the Northern Gafsa Plain in Tunisia. The study is composed of two main parts. The first is interested in the analysis of rainfall spatial and temporal variability in the study basin while the second is devoted to the simulation of groundwater recharge. Rainfall analysis was performed based on annual precipitation data recorded in 6 rainfall stations over a period of 56 years (1960-2015). Potential evapotranspiration data were also collected from 1960 to 2011 (52 years). The hydrologic distributed model WetSpass was used for the estimation of groundwater recharge. Model calibration was performed based on an assessment of the agreement between the sum of recharge and runoff values estimated by the WetSpass hydrological model and those obtained by the climatic method. This latter is based on the difference calculated between rainfall and potential evapotranspiration recorded at each rainy day. Groundwater recharge estimation, on monthly scale, showed that average annual precipitation (183.3 mm/year) was partitioned to 5, 15.3, 36.8, and 42.8% for interception, runoff, actual evapotranspiration and recharge respectively.

  15. Assessing the groundwater recharge under various irrigation schemes in Central Taiwan

    Science.gov (United States)

    Chen, Shih-Kai; Jang, Cheng-Shin; Lin, Zih-Ciao; Tsai, Cheng-Bin

    2014-05-01

    The flooded paddy fields can be considered as a major source of groundwater recharge in Central Taiwan. The risk of rice production has increased notably due to climate change in this area. To respond to agricultural water shortage caused by climate change without affecting rice yield in the future, the application of water-saving irrigation is the substantial resolution. The System of Rice Intensification (SRI) was developed as a set of insights and practices used in growing irrigated rice. Based on the water-saving irrigation practice of SRI, impacts of the new methodology on the reducing of groundwater recharge were assessed in central Taiwan. The three-dimensional finite element groundwater model (FEMWATER) with the variable boundary condition analog functions, was applied in simulating groundwater recharge under different irrigation schemes. According to local climatic and environmental characteristics associated with SRI methodology, the change of infiltration rate was evaluated and compared with the traditional irrigation schemes, including continuous irrigation and rotational irrigation scheme. The simulation results showed that the average infiltration rate in the rice growing season decreased when applying the SRI methodology, and the total groundwater recharge amount of SRI with a 5-day irrigation interval reduced 12% and 9% compared with continuous irrigation (6cm constant ponding water depth) and rotational scheme (5-day irrigation interval with 6 cm initial ponding water depth), respectively. The results could be used as basis for planning long-term adaptive water resource management strategies to climate change in Central Taiwan. Keywords: SRI, Irrigation schemes, Groundwater recharge, Infiltration

  16. Regional Assessment of Groundwater Recharge in the Lower Mekong Basin

    Directory of Open Access Journals (Sweden)

    Guillaume Lacombe

    2017-12-01

    Full Text Available Groundwater recharge remains almost totally unknown across the Mekong River Basin, hindering the evaluation of groundwater potential for irrigation. A regional regression model was developed to map groundwater recharge across the Lower Mekong Basin where agricultural water demand is increasing, especially during the dry season. The model was calibrated with baseflow computed with the local-minimum flow separation method applied to streamflow recorded in 65 unregulated sub-catchments since 1951. Our results, in agreement with previous local studies, indicate that spatial variations in groundwater recharge are predominantly controlled by the climate (rainfall and evapotranspiration while aquifer characteristics seem to play a secondary role at this regional scale. While this analysis suggests large scope for expanding agricultural groundwater use, the map derived from this study provides a simple way to assess the limits of groundwater-fed irrigation development. Further data measurements to capture local variations in hydrogeology will be required to refine the evaluation of recharge rates to support practical implementations.

  17. Artificial groundwater recharge zones mapping using remote sensing and GIS: a case study in Indian Punjab.

    Science.gov (United States)

    Singh, Amanpreet; Panda, S N; Kumar, K S; Sharma, Chandra Shekhar

    2013-07-01

    Artificial groundwater recharge plays a vital role in sustainable management of groundwater resources. The present study was carried out to identify the artificial groundwater recharge zones in Bist Doab basin of Indian Punjab using remote sensing and geographical information system (GIS) for augmenting groundwater resources. The study area has been facing severe water scarcity due to intensive agriculture for the past few years. The thematic layers considered in the present study are: geomorphology (2004), geology (2004), land use/land cover (2008), drainage density, slope, soil texture (2000), aquifer transmissivity, and specific yield. Different themes and related features were assigned proper weights based on their relative contribution to groundwater recharge. Normalized weights were computed using the Saaty's analytic hierarchy process. Thematic layers were integrated in ArcGIS for delineation of artificial groundwater recharge zones. The recharge map thus obtained was divided into four zones (poor, moderate, good, and very good) based on their influence to groundwater recharge. Results indicate that 15, 18, 37, and 30 % of the study area falls under "poor," "moderate," "good," and "very good" groundwater recharge zones, respectively. The highest recharge potential area is located towards western and parts of middle region because of high infiltration rates caused due to the distribution of flood plains, alluvial plain, and agricultural land. The least effective recharge potential is in the eastern and middle parts of the study area due to low infiltration rate. The results of the study can be used to formulate an efficient groundwater management plan for sustainable utilization of limited groundwater resources.

  18. Comparing groundwater recharge and base flow in the Bukmoongol ...

    Indian Academy of Sciences (India)

    model, also known as the Rorabaugh Method. (Rorabaugh 1960; Daniel 1976; Rutledge 2007b), estimates groundwater recharges for each stream- flow peak using the recession-curve-displacement method. It is based on an analytical model that describes groundwater discharge subsequent to recharge to the water table ...

  19. Estimated ground-water recharge from streamflow in Fortymile Wash near Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Savard, C.S.

    1998-01-01

    The two purposes of this report are to qualitatively document ground-water recharge from stream-flow in Fortymile Wash during the period 1969--95 from previously unpublished ground-water levels in boreholes in Fortymile Canyon during 1982--91 and 1995, and to quantitatively estimate the long-term ground-water recharge rate from streamflow in Fortymile Wash for four reaches of Fortymile Wash (Fortymile Canyon, upper Jackass Flats, lower Jackass Flats, and Amargosa Desert). The long-term groundwater recharge rate was estimated from estimates of the volume of water available for infiltration, the volume of infiltration losses from streamflow, the ground-water recharge volume from infiltration losses, and an analysis of the different periods of data availability. The volume of water available for infiltration and ground-water recharge in the four reaches was estimated from known streamflow in ephemeral Fortymile Wash, which was measured at several gaging station locations. The volume of infiltration losses from streamflow for the four reaches was estimated from a streamflow volume loss factor applied to the estimated streamflows. the ground-water recharge volume was estimated from a linear relation between infiltration loss volume and ground-water recharge volume for each of the four reaches. Ground-water recharge rates were estimated for three different periods of data availability (1969--95, 1983--95, and 1992--95) and a long-term ground-water recharge rate estimated for each of the four reaches

  20. Estimated ground-water recharge from streamflow in Fortymile Wash near Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Savard, C.S.

    1998-10-01

    The two purposes of this report are to qualitatively document ground-water recharge from stream-flow in Fortymile Wash during the period 1969--95 from previously unpublished ground-water levels in boreholes in Fortymile Canyon during 1982--91 and 1995, and to quantitatively estimate the long-term ground-water recharge rate from streamflow in Fortymile Wash for four reaches of Fortymile Wash (Fortymile Canyon, upper Jackass Flats, lower Jackass Flats, and Amargosa Desert). The long-term groundwater recharge rate was estimated from estimates of the volume of water available for infiltration, the volume of infiltration losses from streamflow, the ground-water recharge volume from infiltration losses, and an analysis of the different periods of data availability. The volume of water available for infiltration and ground-water recharge in the four reaches was estimated from known streamflow in ephemeral Fortymile Wash, which was measured at several gaging station locations. The volume of infiltration losses from streamflow for the four reaches was estimated from a streamflow volume loss factor applied to the estimated streamflows. the ground-water recharge volume was estimated from a linear relation between infiltration loss volume and ground-water recharge volume for each of the four reaches. Ground-water recharge rates were estimated for three different periods of data availability (1969--95, 1983--95, and 1992--95) and a long-term ground-water recharge rate estimated for each of the four reaches.

  1. Assessment of groundwater recharge potential zone using GIS approach in Purworejo regency, Central Java province, Indonesia

    Science.gov (United States)

    Aryanto, Daniel Eko; Hardiman, Gagoek

    2018-02-01

    Floods and droughts in Purworejo regency are an indication of problems in groundwater management. The current development progress has led to land conversion which has an impact on the problem of water infiltration in Purworejo regency. This study aims to determine the distribution of groundwater recharge potential zones by using geographic information system as the basis for ground water management. The groundwater recharge potential zone is obtained by overlaying all the thematic maps that affect the groundwater infiltration. Each thematic map is weighted according to its effect on groundwater infiltration such as land-use - 25%, rainfall - 20%, litology - 20%, soil - 15%, slope - 10%, lineament - 5%, and river density - 5% to find groundwater recharge potential zones. The groundwater recharge potential zones thus obtained were divided into five categories, viz., very high, high, medium, low and very low zones. The results of this study may be useful for better groundwater planning and management.

  2. Changes in Projected Spatial and Seasonal Groundwater Recharge in the Upper Colorado River Basin.

    Science.gov (United States)

    Tillman, Fred D; Gangopadhyay, Subhrendu; Pruitt, Tom

    2017-07-01

    The Colorado River is an important source of water in the western United States, supplying the needs of more than 38 million people in the United States and Mexico. Groundwater discharge to streams has been shown to be a critical component of streamflow in the Upper Colorado River Basin (UCRB), particularly during low-flow periods. Understanding impacts on groundwater in the basin from projected climate change will assist water managers in the region in planning for potential changes in the river and groundwater system. A previous study on changes in basin-wide groundwater recharge in the UCRB under projected climate change found substantial increases in temperature, moderate increases in precipitation, and mostly periods of stable or slight increases in simulated groundwater recharge through 2099. This study quantifies projected spatial and seasonal changes in groundwater recharge within the UCRB from recent historical (1950 to 2015) through future (2016 to 2099) time periods, using a distributed-parameter groundwater recharge model with downscaled climate data from 97 Coupled Model Intercomparison Project Phase 5 (CMIP5) climate projections. Simulation results indicate that projected increases in basin-wide recharge of up to 15% are not distributed uniformly within the basin or throughout the year. Northernmost subregions within the UCRB are projected an increase in groundwater recharge, while recharge in other mainly southern subregions will decline. Seasonal changes in recharge also are projected within the UCRB, with decreases of 50% or more in summer months and increases of 50% or more in winter months for all subregions, and increases of 10% or more in spring months for many subregions. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  3. Groundwater Recharge Processes Revealed By Multi-Tracers Approach in a Headwater, North China Plain

    Science.gov (United States)

    Sakakibara, K.; Tsujimura, M.; Song, X.; Zhang, J.

    2014-12-01

    Groundwater recharge variation in space and time is crucial for effective water management especially in arid/ semi-arid regions. In order to reveal comprehensive groundwater recharge processes in a catchment with a large topographical relief and seasonal hydrological variations, intensive field surveys were conducted at 4 times in different seasons in Wangkuai watershed, Taihang Mountains, which is a main groundwater recharge zone of North China Plain. The groundwater, spring, stream water and lake water were sampled, and inorganic solute constituents and stable isotopes of oxygen-18 and deuterium were determined on all water samples. Also, the stream flow rate was observed in stable state condition. The stable isotopic compositions, silica and bicarbonate concentrations in the groundwater show close values as those in the surface water, suggesting main groundwater recharge occurs from surface water at mountain-plain transitional zone throughout a year. Also, the deuterium and oxgen-18 in the Wangkuai reservoir and the groundwater in the vicinity of the reservoir show higher values, suggesting the reservoir water, affected by evaporation effect, seems to have an important role for the groundwater recharge in alluvial plain. For specifying the groundwater recharge area and quantifying groundwater recharge rate from the reservoir, an inversion analysis and a simple mixing model were applied in Wangkuai watershed using stable isotopes of oxygen-18 and deuterium. The model results show that groundwater recharge occurs dominantly at the altitude from 357 m to 738 m corresponding to mountain-plain transitional zone, and groundwater recharge rate by Wangkuai reservoir is estimated to be 2.4 % of total groundwater recharge in Wangkuai watershed.

  4. Understanding and quantifying focused, indirect groundwater recharge from ephemeral streams using water table fluctuations

    Science.gov (United States)

    Cuthbert, M. O.; Acworth, R. I.; Andersen, M. S.; Larsen, J. R.; McCallum, A. M.; Rau, G. C.; Tellam, J. H.

    2016-02-01

    Understanding and managing groundwater resources in drylands is a challenging task, but one that is globally important. The dominant process for dryland groundwater recharge is thought to be as focused, indirect recharge from ephemeral stream losses. However, there is a global paucity of data for understanding and quantifying this process and transferable techniques for quantifying groundwater recharge in such contexts are lacking. Here we develop a generalized conceptual model for understanding water table and groundwater head fluctuations due to recharge from episodic events within ephemeral streams. By accounting for the recession characteristics of a groundwater hydrograph, we present a simple but powerful new water table fluctuation approach to quantify focused, indirect recharge over both long term and event time scales. The technique is demonstrated using a new, and globally unparalleled, set of groundwater observations from an ephemeral stream catchment located in NSW, Australia. We find that, following episodic streamflow events down a predominantly dry channel system, groundwater head fluctuations are controlled by pressure redistribution operating at three time scales from vertical flow (days to weeks), transverse flow perpendicular to the stream (weeks to months), and longitudinal flow parallel to the stream (years to decades). In relative terms, indirect recharge decreases almost linearly away from the mountain front, both in discrete monitored events as well as in the long-term average. In absolute terms, the estimated indirect recharge varies from 80 to 30 mm/a with the main uncertainty in these values stemming from uncertainty in the catchment-scale hydraulic properties.

  5. Ground-water recharge in the arid and semiarid southwestern United States

    Science.gov (United States)

    Stonestrom, David A.; Constantz, Jim; Ferré, Ty P.A.; Leake, Stanley A.

    2007-01-01

    areas, and distinct modes of recharge in the Colorado Plateau and Basin and Range subregions.The chapters in this professional paper present (first) an overview of climatic and hydrogeologic framework (chapter A), followed by a regional analysis of ground-water recharge across the entire study area (chapter B). These are followed by an overview of site-specific case studies representing different subareas of the geographically diverse arid and semiarid southwestern United States (chapter C); the case studies themselves follow in chapters D–K. The regional analysis includes detailed hydrologic modeling within the framework of a high-resolution geographic-information system (GIS). Results from the regional analysis are used to explore both the distribution of ground-water recharge for mean climatic conditions as well as the influence of two climatic patterns—the El Niño-Southern Oscillation and Pacific Decadal Oscillation—that impart a high degree of variability to the hydrologic cycle. Individual case studies employ a variety of geophysical and geochemical techniques to investigate recharge processes and relate the processes to local geologic and climatic conditions. All of the case studies made use of naturally occurring tracers to quantify recharge. Thermal and geophysical techniques that were developed in the course of the studies are presented in appendices.The quantification of ground-water recharge in arid settings is inherently difficult due to the generally low amount of recharge, its spatially and temporally spotty nature, and the absence of techniques for directly measuring fluxes entering the saturated zone from the unsaturated zone. Deep water tables in arid alluvial basins correspond to thick unsaturated zones that produce up to millennial time lags between changes in hydrologic conditions at the land surface and subsequent changes in recharge to underlying ground water. Recent advances in physical, chemical, isotopic, and modeling techniques have

  6. Transitioning Groundwater from an Extractive Resource to a Managed Water Storage Resource: Geology and Recharge in Sedimentary Basins

    Science.gov (United States)

    Maples, S.; Fogg, G. E.; Maxwell, R. M.; Liu, Y.

    2017-12-01

    Civilizations have typically obtained water from natural and constructed surface-water resources throughout most of human history. Only during the last 50-70 years has a significant quantity of water for humans been obtained through pumping from wells. During this short time, alarming levels of groundwater depletion have been observed worldwide, especially in some semi-arid and arid regions that rely heavily on groundwater pumping from clastic sedimentary basins. In order to reverse the negative effects of over-exploitation of groundwater resources, we must transition from treating groundwater mainly as an extractive resource to one in which recharge and subsurface storage are pursued more aggressively. However, this remains a challenge because unlike surface-water reservoirs which are typically replenished over annual timescales, the complex geologic architecture of clastic sedimentary basins impedes natural groundwater recharge rates resulting in decadal or longer timescales for aquifer replenishment. In parts of California's Central Valley alluvial aquifer system, groundwater pumping has outpaced natural groundwater recharge for decades. Managed aquifer recharge (MAR) has been promoted to offset continued groundwater overdraft, but MAR to the confined aquifer system remains a challenge because multiple laterally-extensive silt and clay aquitards limit recharge rates in most locations. Here, we simulate the dynamics of MAR and identify potential recharge pathways in this system using a novel combination of (1) a high-resolution model of the subsurface geologic heterogeneity and (2) a physically-based model of variably-saturated, three-dimensional water flow. Unlike most groundwater models, which have coarse spatial resolution that obscures the detailed subsurface geologic architecture of these systems, our high-resolution model can pinpoint specific geologic features and locations that have the potential to `short-circuit' aquitards and provide orders

  7. Artificial recharge of groundwater and its role in water management

    Science.gov (United States)

    Kimrey, J.O.

    1989-01-01

    This paper summarizes and discusses the various aspects and methods of artificial recharge with particular emphasis on its uses and potential role in water management in the Arabian Gulf region. Artificial recharge occurs when man's activities cause more water to enter an aquifer, either under pumping or non-pumping conditions, than otherwise would enter the aquifer. Use of artificial recharge can be a practical means of dealing with problems of overdraft of groundwater. Methods of artificial recharge may be grouped under two broad types: (a) water spreading techniques, and (b) well-injection techniques. Successful use of artificial recharge requires a thorough knowledge of the physical and chemical characteristics of the aquifier system, and extensive onsite experimentation and tailoring of the artificial-recharge technique to fit the local or areal conditions. In general, water spreading techniques are less expensive than well injection and large quantities of water can be handled. Water spreading can also result in significant improvement in quality of recharge waters during infiltration and movement through the unsaturated zone and the receiving aquifer. In comparison, well-injection techniques are often used for emplacement of fresh recharge water into saline aquifer zones to form a manageable lens of fresher water, which may later be partially withdrawn for use or continue to be maintained as a barrier against salt-water encroachment. A major advantage in use of groundwater is its availability, on demand to wells, from a natural storage reservoir that is relatively safe from pollution and from damage by sabotage or other hostile action. However, fresh groundwater occurs only in limited quantities in most of the Arabian Gulf region; also, it is heavily overdrafted in many areas, and receives very little natural recharge. Good use could be made of artificial recharge by well injection in replenishing and managing aquifers in strategic locations if sources of

  8. Groundwater Recharge Process in the Morondava Sedimentary Basin, Southwestern Madagascar

    International Nuclear Information System (INIS)

    Mamifarananahary, E.; Rajaobelison, J.; Ramaroson, V.; Rahobisoa, J.J.

    2007-01-01

    The groundwater recharge process in the Morondava Sedimentary basin was determined using chemical and isotopic tools. The results showed that the main recharge into shallow aquifer is from infiltration of evaporated water. Into deeper aquifer, it is done either from direct infiltration of rainfall from recharge areas on the top of the hill in the East towards the low-lying discharge areas in the West, or from vertical infiltration of evaporated shallow groundwater. The tritium contents suggest that recharge from shallow aquifers is from recent rainfall with short residence time while recharge into deeper aquifers is from older rainfall with longer residence time.

  9. Recharge behavior to groundwater in the command area of Heran distributary, Sanghar, Sindh

    International Nuclear Information System (INIS)

    Lashari, B.K.

    2004-01-01

    Determination of net recharge to the groundwater is of prime importance while managing irrigation and drainage system of the area. Without knowing the groundwater and recharge both systems irrigation and drainage, are two sides of one coin may mislead. In order to determine net recharge to the groundwater, the data of important parameters such as irrigation delivery at head of the channel, total losses, crop water requirement, water table fluctuation, operation hours of tube wells and surface drain discharge and shallow as well as deep ground water quality were measured for Rabi season (November, 1999 to March, 2000). Using different approaches such as actual observation of inflow and outflow components, change of water table and SURFER (Software), the net recharge was determined. Results have shown that in Rabi season, the groundwater is recharged except in the month of January (canal closure period) and March, depending on various irrigation and drainage factors, which are complex. Shallow groundwater quality was observed good and use able due to recharge by surface water. About 41 % of command area was under shallow water table with salinity of water 300-800 ppm, 29 % was under water quality of 800-1300 ppm, 9% was between 1800-2300 ppm and rest 12% of the area was observed more than 2300 ppm. The quality of fresh water pump lifting water from the depth of 40 ft was up to 2400 ppm and deeper pump water quality was about 25000 ppm in scavenger and saline tube wells. Average water table was about 3.0 ft and fluctuation was between 2.38-3.8 feet in spite of running the tube wells.(author)

  10. Groundwater recharge in desert playas: current rates and future effects of climate change

    Science.gov (United States)

    McKenna, Owen P.; Sala, Osvaldo E.

    2018-01-01

    Our results from playas, which are topographic low areas situated in closed-catchments in drylands, indicated that projected climate change in Southwestern USA would have a net positive impact over runon and groundwater recharge beneath playas. Expected increased precipitation variability can cause up to a 300% increase in annual groundwater recharge beneath playas. This increase will overshadow the effect of decreased precipitation amount that could cause up to a 50% decrease in recharge beneath playas. These changes could have a significant impact on groundwater and carbon storage. These results are important given that groundwater resources in Southwestern USA continue to decline due to human consumption outpacing natural recharge of aquifers. Here, we report on groundwater recharge rates ranging from less than 1 mm to greater than 25 mm per year beneath desert playas. Playas located in larger and steeper catchments with finer-textured soils had the highest rates of recharge. Vegetation cover had no effect on recharge beneath playas. We modeled catchment runoff generation and found that the amount of runon a playa receives annually strongly correlated to the rate of groundwater recharge beneath that playa. Runon occurred during precipitation events larger than 20 mm and increased linearly with events above that threshold.

  11. Spatial distribution of groundwater recharge and base flow: Assessment of controlling factors

    Directory of Open Access Journals (Sweden)

    Z. Zomlot

    2015-09-01

    New hydrological insights for the region: The average resulting recharge is 235 mm/year and occurs mainly in winter. The overall moderate correlation between base flow estimates and modeled recharge rates indicates that base flow is a reasonable proxy of recharge. Groundwater recharge variation was explained in order of importance by precipitation, soil texture and vegetation cover; while base flow variation was strongly controlled by vegetation cover and groundwater depth. The results of this study highlight the important role of spatial variables in estimation of recharge and base flow. In addition, the prominent role of vegetation makes clear the potential importance of land-use changes on recharge and hence the need to include a proper strategy for land-use change in sustainable management of groundwater resources.

  12. Reassessment of Ground-Water Recharge and Simulated Ground-Water Availability for the Hawi Area of North Kohala, Hawaii

    Science.gov (United States)

    Oki, Delwyn S.

    2002-01-01

    An estimate of ground-water availability in the Hawi area of north Kohala, Hawaii, is needed to determine whether ground-water resources are adequate to meet future demand within the area and other areas to the south. For the Hawi area, estimated average annual recharge from infiltration of rainfall, fog drip, and irrigation is 37.5 million gallons per day from a daily water budget. Low and high annual recharge estimates for the Hawi area that incorporate estimated uncertainty are 19.9 and 55.4 million gallons per day, respectively. The recharge estimates from this study are lower than the recharge of 68.4 million gallons per day previously estimated from a monthly water budget. Three ground-water models, using the low, intermediate, and high recharge estimates (19.9, 37.5, and 55.4 million gallons per day, respectively), were developed for the Hawi area to simulate ground-water levels and discharges for the 1990?s. To assess potential ground-water availability, the numerical ground-water flow models were used to simulate the response of the freshwater-lens system to withdrawals at rates in excess of the average 1990?s withdrawal rates. Because of uncertainty in the recharge estimate, estimates of ground-water availability also are uncertain. Results from numerical simulations indicate that for appropriate well sites, depths, and withdrawal rates (1) for the low recharge estimate (19.9 million gallons per day) it may be possible to develop an additional 10 million gallons per day of fresh ground water from the Hawi area and maintain a freshwater-lens thickness of 160 feet near the withdrawal sites, (2) for the intermediate recharge estimate (37.5 million gallons per day) it may be possible to develop an additional 15 million gallons per day of fresh ground water from the Hawi area and maintain a freshwater-lens thickness of 190 feet near the withdrawal sites, and (3) for the high recharge estimate (55.4 million gallons per day) it may be possible to develop at

  13. Sensitivity of groundwater recharge using climatic analogues and HYDRUS-1D

    Directory of Open Access Journals (Sweden)

    B. Leterme

    2012-08-01

    Full Text Available The sensitivity of groundwater recharge to different climate conditions was simulated using the approach of climatic analogue stations, i.e. stations presently experiencing climatic conditions corresponding to a possible future climate state. The study was conducted in the context of a safety assessment of a future near-surface disposal facility for low and intermediate level short-lived radioactive waste in Belgium; this includes estimation of groundwater recharge for the next millennia. Groundwater recharge was simulated using the Richards based soil water balance model HYDRUS-1D and meteorological time series from analogue stations. This study used four analogue stations for a warmer subtropical climate with changes of average annual precipitation and potential evapotranspiration from −42% to +5% and from +8% to +82%, respectively, compared to the present-day climate. Resulting water balance calculations yielded a change in groundwater recharge ranging from a decrease of 72% to an increase of 3% for the four different analogue stations. The Gijon analogue station (Northern Spain, considered as the most representative for the near future climate state in the study area, shows an increase of 3% of groundwater recharge for a 5% increase of annual precipitation. Calculations for a colder (tundra climate showed a change in groundwater recharge ranging from a decrease of 97% to an increase of 32% for four different analogue stations, with an annual precipitation change from −69% to −14% compared to the present-day climate.

  14. Groundwater Recharge and Flow Regime revealed by multi-tracers approach in a headwater, North China Plain

    Science.gov (United States)

    Sakakibara, Koichi; Tsujimura, Maki; Song, Xianfang; Zhang, Jie

    2014-05-01

    Groundwater recharge is a crucial hydrological process for effective water management especially in arid/ semi-arid regions. However, the insufficient number of specific research regarding groundwater recharge process has been reported previously. Intensive field surveys were conducted during rainy season, mid dry season, and end of dry season, in order to clarify comprehensive groundwater recharge and flow regime of Wangkuai watershed in a headwater, which is a main recharge zone of North China Plain. The groundwater, spring, stream water and lake water were sampled, and inorganic solute constituents and stable isotopes of oxygen 18 and deuterium were determined on all water samples. Also the stream flow rate was observed. The solute ion concentrations and stable isotopic compositions show that the most water of this region can be characterized by Ca-HCO3 type and the main water source is precipitation which is affected by altitude effect of stable isotopes. In addition, the river and reservoir of the area seem to recharge the groundwater during rainy season, whereas interaction between surface water and groundwater does not become dominant gradually after the rainy season. The inversion analysis applied in Wangkuai watershed using simple mixing model represents an existing multi-flow systems which shows a distinctive tracer signal and flow rate. In summary, the groundwater recharged at different locations in the upper stream of Wangkuai reservoir flows downward to alluvial fan with a certain amount of mixing together, also the surface water recharges certainly the groundwater in alluvial plain in the rainy season.

  15. Estimating Natural Recharge in a Desert Environment Facing Increasing Ground-Water Demands

    Science.gov (United States)

    Nishikawa, T.; Izbicki, J. A.; Hevesi, J. A.; Martin, P.

    2004-12-01

    Ground water historically has been the sole source of water supply for the community of Joshua Tree in the Joshua Tree ground-water subbasin of the Morongo ground-water basin in the southern Mojave Desert. Joshua Basin Water District (JBWD) supplies water to the community from the underlying Joshua Tree ground-water subbasin, and ground-water withdrawals averaging about 960 acre-ft/yr have resulted in as much as 35 ft of drawdown. As growth continues in the desert, ground-water resources may need to be supplemented using imported water. To help meet future demands, JBWD plans to construct production wells in the adjacent Copper Mountain ground-water subbasin. To manage the ground-water resources and to identify future mitigating measures, a thorough understanding of the ground-water system is needed. To this end, field and numerical techniques were applied to determine the distribution and quantity of natural recharge. Field techniques included the installation of instrumented boreholes in selected washes and at a nearby control site. Numerical techniques included the use of a distributed-parameter watershed model and a ground-water flow model. The results from the field techniques indicated that as much as 70 acre-ft/yr of water infiltrated downward through the two principal washes during the study period (2001-3). The results from the watershed model indicated that the average annual recharge in the ground-water subbasins is about 160 acre-ft/yr. The results from the calibrated ground-water flow model indicated that the average annual recharge for the same area is about 125 acre-ft/yr. Although the field and numerical techniques were applied to different scales (local vs. large), all indicate that natural recharge in the Joshua Tree area is very limited; therefore, careful management of the limited ground-water resources is needed. Moreover, the calibrated model can now be used to estimate the effects of different water-management strategies on the ground-water

  16. Modelling of recharge and pollutant fluxes to urban groundwaters

    International Nuclear Information System (INIS)

    Thomas, Abraham; Tellam, John

    2006-01-01

    Urban groundwater resources are of considerable importance to the long-term viability of many cities world-wide, yet prediction of the quantity and quality of recharge is only rarely attempted at anything other than a very basic level. This paper describes the development of UGIf, a simple model written within a GIS, designed to provide estimates of spatially distributed recharge and recharge water quality in unconfined but covered aquifers. The following processes (with their calculation method indicated) are included: runoff and interception (curve number method); evapotranspiration (Penman-Grindley); interflow (empirical index approach); volatilization (Henry's law); sorption (distribution coefficient); and degradation (first order decay). The input data required are: meteorological data, landuse/cover map with event mean concentration attributes, geological maps with hydraulic and geochemical attributes, and topographic and water table elevation data in grid form. Standard outputs include distributions of: surface runoff, infiltration, potential recharge, ground level slope, interflow, actual recharge, pollutant fluxes in surface runoff, travel times of each pollutant through the unsaturated zone, and the pollutant fluxes and concentrations at the water table. The process of validation has commenced with a study of the Triassic Sandstone aquifer underlying Birmingham, UK. UGIf predicts a similar average recharge rate for the aquifer as previous groundwater flow modelling studies, but with significantly more spatial detail: in particular the results indicate that recharge through paved areas may be more important than previously thought. The results also highlight the need for more knowledge/data on the following: runoff estimation; interflow (including the effects of lateral flow and channelling on flow times and therefore chemistry); evapotranspiration in paved areas; the nature of unsaturated zone flow below paved areas; and the role of the pipe network

  17. Groundwater recharge in the tropics: a pan-African analysis of observations

    Science.gov (United States)

    Taylor, R. G.

    2015-12-01

    Groundwater is a vital source of freshwater in sub-Saharan Africa where rainfall and river discharge are unreliable and per-capita reservoir storage is among the lowest in the world. Groundwater is widely considered a distributed, low-cost and climate-resilient option to meet rapidly growing freshwater demand and alleviate endemic poverty by expanding access to safe water and improving food security through irrigation. Recent research indicates that groundwater storage in Africa is about 100 times greater than annual river discharge yet major uncertainties remain in the magnitude and nature of replenishment through recharge as well as the impacts of land-use and climate change. Here, we present newly compiled, multi-decadal observations of groundwater levels from 5 countries (Benin, Burkina Faso, Niger, Tanzania, Uganda) and paired measurements of stable isotope ratios of O and H in precipitation and groundwater at 11 locations. These data reveal both a distinct bias in groundwater recharge to intensive rainfall and rapid recharge pathways (e.g. focused, macropore flow) that are inconsistent with conventional recharge models assuming pore-matrix flow defined by the Darcy-Richards equation. Further the records highlight the substantial influence of land-use change (e.g. conversion of natural, perennial cover to croplands) on groundwater recharge. The compiled observations also provide, for the first time, a pan-African baseline to evaluate the performance of large-scale hydrological models and Land-Surface Models incorporating groundwater in this region. Our results suggest that the intensification of precipitation brought about by global warming favours groundwater replenishment in sub-Saharan Africa. As such, groundwater may prove to be a climate-resilient source of freshwater in the tropics, enabling adaptive strategies such as groundwater-fed irrigation and sustaining domestic and industrial water supplies.

  18. Delineation of groundwater recharge areas, western Cape Cod, Massachusetts

    Science.gov (United States)

    Masterson, John P.; Walter, Donald A.

    2000-01-01

    The unconfined sand-and-gravel aquifer in western Cape Cod, Massachusetts, which is the sole source of water supply for the communities in the area, is recharged primarily from precipitation. The rate of recharge from precipitation is estimated to be about 26 inches per year (in/yr), or about 60 percent of the precipitation rate. This recharge rate yields a flow through the aquifer of about 180 million gallons per day (Mgal/d). Groundwater flows radially outward from the top of the water-table mound in the north-central part of the flow system toward the coast, as indicated by the water-table contours on the large map on this sheet. Recharge that reaches the water table near the top of the mound travels deeper through the aquifer than recharge that reaches the water table closer to the coast. All recharge to the aquifer ultimately discharges to pumping wells, streams, or coastal areas; however, some of this recharge may flow first through kettle ponds before eventually reaching these discharge points.

  19. Implications of projected climate change for groundwater recharge in the western United States

    Science.gov (United States)

    Meixner, Thomas; Manning, Andrew H.; Stonestrom, David A.; Allen, Diana M.; Ajami, Hoori; Blasch, Kyle W.; Brookfield, Andrea E.; Castro, Christopher L.; Clark, Jordan F.; Gochis, David J.; Flint, Alan L.; Neff, Kirstin L.; Niraula, Rewati; Rodell, Matthew; Scanlon, Bridget R.; Singha, Kamini; Walvoord, Michelle A.

    2016-03-01

    Existing studies on the impacts of climate change on groundwater recharge are either global or basin/location-specific. The global studies lack the specificity to inform decision making, while the local studies do little to clarify potential changes over large regions (major river basins, states, or groups of states), a scale often important in the development of water policy. An analysis of the potential impact of climate change on groundwater recharge across the western United States (west of 100° longitude) is presented synthesizing existing studies and applying current knowledge of recharge processes and amounts. Eight representative aquifers located across the region were evaluated. For each aquifer published recharge budget components were converted into four standard recharge mechanisms: diffuse, focused, irrigation, and mountain-systems recharge. Future changes in individual recharge mechanisms and total recharge were then estimated for each aquifer. Model-based studies of projected climate-change effects on recharge were available and utilized for half of the aquifers. For the remainder, forecasted changes in temperature and precipitation were logically propagated through each recharge mechanism producing qualitative estimates of direction of changes in recharge only (not magnitude). Several key patterns emerge from the analysis. First, the available estimates indicate average declines of 10-20% in total recharge across the southern aquifers, but with a wide range of uncertainty that includes no change. Second, the northern set of aquifers will likely incur little change to slight increases in total recharge. Third, mountain system recharge is expected to decline across much of the region due to decreased snowpack, with that impact lessening with higher elevation and latitude. Factors contributing the greatest uncertainty in the estimates include: (1) limited studies quantitatively coupling climate projections to recharge estimation methods using detailed

  20. Implications of projected climate change for groundwater recharge in the western United States

    Science.gov (United States)

    Meixner, Thomas; Manning, Andrew H.; Stonestrom, David A.; Allen, Diana M.; Ajami, Hoori; Blasch, Kyle W.; Brookfield, Andrea E.; Castro, Christopher L.; Clark, Jordan F.; Gochis, David; Flint, Alan L.; Neff, Kirstin L.; Niraula, Rewati; Rodell, Matthew; Scanlon, Bridget R.; Singha, Kamini; Walvoord, Michelle Ann

    2016-01-01

    Existing studies on the impacts of climate change on groundwater recharge are either global or basin/location-specific. The global studies lack the specificity to inform decision making, while the local studies do little to clarify potential changes over large regions (major river basins, states, or groups of states), a scale often important in the development of water policy. An analysis of the potential impact of climate change on groundwater recharge across the western United States (west of 100° longitude) is presented synthesizing existing studies and applying current knowledge of recharge processes and amounts. Eight representative aquifers located across the region were evaluated. For each aquifer published recharge budget components were converted into four standard recharge mechanisms: diffuse, focused, irrigation, and mountain-systems recharge. Future changes in individual recharge mechanisms and total recharge were then estimated for each aquifer. Model-based studies of projected climate-change effects on recharge were available and utilized for half of the aquifers. For the remainder, forecasted changes in temperature and precipitation were logically propagated through each recharge mechanism producing qualitative estimates of direction of changes in recharge only (not magnitude). Several key patterns emerge from the analysis. First, the available estimates indicate average declines of 10–20% in total recharge across the southern aquifers, but with a wide range of uncertainty that includes no change. Second, the northern set of aquifers will likely incur little change to slight increases in total recharge. Third, mountain system recharge is expected to decline across much of the region due to decreased snowpack, with that impact lessening with higher elevation and latitude. Factors contributing the greatest uncertainty in the estimates include: (1) limited studies quantitatively coupling climate projections to recharge estimation methods using

  1. A synopsis of climate change effects on groundwater recharge

    Science.gov (United States)

    Smerdon, Brian D.

    2017-12-01

    Six review articles published between 2011 and 2016 on groundwater and climate change are briefly summarized. This synopsis focuses on aspects related to predicting changes to groundwater recharge conditions, with several common conclusions between the review articles being noted. The uncertainty of distribution and trend in future precipitation from General Circulation Models (GCMs) results in varying predictions of recharge, so much so that modelling studies are often not able to predict the magnitude and direction (increase or decrease) of future recharge conditions. Evolution of modelling approaches has led to the use of multiple GCMs and hydrologic models to create an envelope of future conditions that reflects the probability distribution. The choice of hydrologic model structure and complexity, and the choice of emissions scenario, has been investigated and somewhat resolved; however, recharge results remain sensitive to downscaling methods. To overcome uncertainty and provide practical use in water management, the research community indicates that modelling at a mesoscale, somewhere between watersheds and continents, is likely ideal. Improvements are also suggested for incorporating groundwater processes within GCMs.

  2. Integrated Assessment Of Groundwater Recharge In The North Kelantan River Basin Using Environmental Water Stable Isotopes, Tritium And Chloride Data

    International Nuclear Information System (INIS)

    Wan Zakaria Wan Muhamad Tahir; Nur Hayati Hussin; Ismail Yusof; Kamaruzaman Mamat; Johari Abdul Latif; Rohaimah Demanah

    2014-01-01

    Estimation and understanding of groundwater recharge mechanism and capacity of aquifer are essential issues in water resources investigation. An integrated study of environmental chloride content in the unsaturated zone using chloride mass balance method (CMB) and isotopic analyses of deuterium, oxygen-18, and tritium values range in the alluvial channel aquifer profiles (quaternary sediments) of the North Kelantan River basin has been carried out in order to estimate and understand groundwater recharge processes. However, the rate of aquifer recharge is one of the most difficult factors to measure in the evaluation of ground water resources. Estimation of recharge, by whatever method, is normally subject to large uncertainties and errors. In this paper, changes in stable isotopic signatures in different seasons and tritium analysis of the sampled groundwater observed at different depth in the aquifer system were evaluated. Stable isotope data are slightly below the local meteoric water line (LMWL) indicating that there is some isotopic enrichment due to direct evaporation through the soil surface which is exposed prior or during the recharging process. The overall data on water isotopic signatures from boreholes and production wells (shallow and relatively deep aquifer system) are spread over a fairly small range but somewhat distinct compared to river water isotopic compositions. Such a narrow variation in isotopic signatures of the sampled groundwaters may suggest that all groundwater samples originated from the same area of direct recharge predominantly from rainfall and nearby rivers. Environmental tritium data measured in groundwater at different depths and locations together with a medium-term of limited monthly rainfall collections were used to investigate the groundwater age distributions (residence times). The existence of groundwater in the aquifer system (sampled wells) is predominantly designated as modern (young) water that has undergone recharged

  3. Groundwater Recharge and Flow Processes in Taihang Mountains, a Semi-humid Region, North China

    Science.gov (United States)

    Sakakibara, Koichi; Tsujimura, Maki; Song, Xianfang; Zhang, Jie

    2015-04-01

    Groundwater flow/recharge variations in time and space are crucial for effective water management especially in semi-arid and semi-humid regions. In order to reveal comprehensive groundwater flow/recharge processes in a catchment with a large topographical relief and seasonal hydrological variations, intensive field surveys were undertaken at 4 times in different seasons (June 2011, August 2012, November 2012, February 2014) in the Wangkuai watershed, Taihang mountains, which is a main groundwater recharge area of the North China Plain. The groundwater, spring, stream water and reservoir water were taken, and inorganic solute constituents and stable isotopes of oxygen-18 and deuterium were determined on all water samples. Also, the stream flow rate and the depth of groundwater table were observed. The stable isotopic compositions and inorganic solute constituents in the groundwater are depleted and shown similar values as those of the surface water at the mountain-plain transitional area. Additionally, the groundwater in the vicinity of the Wangkuai Reservoir presents clearly higher stable isotopic compositions and lower d-excess than those of the stream water, indicating the groundwater around the reservoir is affected by evaporation same as the Wangkuai Reservoir itself. Hence, the surface water in the mountain-plain transitional area and Wangkuai Reservoir are principal groundwater recharge sources. An inversion analysis and simple mixing model were applied in the Wangkuai watershed using stable isotopes of oxygen-18 and deuterium to construct a groundwater flow model. The model shows that multi-originated groundwater flows from upstream to downstream along topography with certain mixing. In addition, the groundwater recharge occurs dominantly at the altitude from 421 m to 953 m, and the groundwater recharge rate by the Wangkuai Reservoir is estimated to be 2.4 % of the total groundwater recharge in the Wangkuai watershed. Therefore, the stream water and

  4. Groundwater recharge in suburban areas of Hanoi, Vietnam: effect of decreasing surface-water bodies and land-use change

    Science.gov (United States)

    Kuroda, Keisuke; Hayashi, Takeshi; Do, An Thuan; Canh, Vu Duc; Nga, Tran Thi Viet; Funabiki, Ayako; Takizawa, Satoshi

    2017-05-01

    Over-exploited groundwater is expected to remain the predominant source of domestic water in suburban areas of Hanoi, Vietnam. In order to evaluate the effect on groundwater recharge, of decreasing surface-water bodies and land-use change caused by urbanization, the relevant groundwater systems and recharge pathways must be characterized in detail. To this end, water levels and water quality were monitored for 3 years regarding groundwater and adjacent surface-water bodies, at two typical suburban sites in Hanoi. Stable isotope (δ18O, δD of water) analysis and hydrochemical analysis showed that the water from both aquifers and aquitards, including the groundwater obtained from both the monitoring wells and the neighboring household tubewells, was largely derived from evaporation-affected surface-water bodies (e.g., ponds, irrigated farmlands) rather than from rivers. The water-level monitoring results suggested distinct local-scale flow systems for both a Holocene unconfined aquifer (HUA) and Pleistocene confined aquifer (PCA). That is, in the case of the HUA, lateral recharge through the aquifer from neighboring ponds and/or irrigated farmlands appeared to be dominant, rather than recharge by vertical rainwater infiltration. In the case of the PCA, recharge by the above-lying HUA, through areas where the aquitard separating the two aquifers was relatively thin or nonexistent, was suggested. As the decrease in the local surface-water bodies will likely reduce the groundwater recharge, maintaining and enhancing this recharge (through preservation of the surface-water bodies) is considered as essential for the sustainable use of groundwater in the area.

  5. The effect of modeled recharge distribution on simulated groundwater availability and capture.

    Science.gov (United States)

    Tillman, F D; Pool, D R; Leake, S A

    2015-01-01

    Simulating groundwater flow in basin-fill aquifers of the semiarid southwestern United States commonly requires decisions about how to distribute aquifer recharge. Precipitation can recharge basin-fill aquifers by direct infiltration and transport through faults and fractures in the high-elevation areas, by flowing overland through high-elevation areas to infiltrate at basin-fill margins along mountain fronts, by flowing overland to infiltrate along ephemeral channels that often traverse basins in the area, or by some combination of these processes. The importance of accurately simulating recharge distributions is a current topic of discussion among hydrologists and water managers in the region, but no comparative study has been performed to analyze the effects of different recharge distributions on groundwater simulations. This study investigates the importance of the distribution of aquifer recharge in simulating regional groundwater flow in basin-fill aquifers by calibrating a groundwater-flow model to four different recharge distributions, all with the same total amount of recharge. Similarities are seen in results from steady-state models for optimized hydraulic conductivity values, fit of simulated to observed hydraulic heads, and composite scaled sensitivities of conductivity parameter zones. Transient simulations with hypothetical storage properties and pumping rates produce similar capture rates and storage change results, but differences are noted in the rate of drawdown at some well locations owing to the differences in optimized hydraulic conductivity. Depending on whether the purpose of the groundwater model is to simulate changes in groundwater levels or changes in storage and capture, the distribution of aquifer recharge may or may not be of primary importance. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

  6. The study of using earth tide response of groundwater level and rainfall recharge to identify groundwater aquifer

    Science.gov (United States)

    Huang, W. J.; Hsu, C. H.; Chang, L. C.; Chiang, C. J.; Wang, Y. S.; Lu, W. C.

    2017-12-01

    Hydrogeological framework is the most important basis for groundwater analysis and simulation. Conventionally, the core drill is a most commonly adopted skill to acquire the core's data with the help of other research methods to artificially determine the result. Now, with the established groundwater station network, there are a lot of groundwater level information available. Groundwater level is an integrated presentation of the hydrogeological framework and the external pumping and recharge system. Therefore, how to identify the hydrogeological framework from a large number of groundwater level data is an important subject. In this study, the frequency analysis method and rainfall recharge mechanism were used to identify the aquifer where the groundwater level's response frequency and amplitude react to the earth tide. As the earth tide change originates from the gravity caused by the paths of sun and moon, it leads to soil stress and strain changes, which further affects the groundwater level. The scale of groundwater level's change varies with the influence of aquifer pressure systems such as confined or unconfined aquifers. This method has been applied to the identification of aquifers in the Cho-Shui River Alluvial Fan. The results of the identification are compared to the records of core drill and they both are quite consistent. It is shown that the identification methods developed in this study can considerably contribute to the identification of hydrogeological framework.

  7. Modelling the effects of climate and land cover change on groundwater recharge in south-west Western Australia

    Directory of Open Access Journals (Sweden)

    W. Dawes

    2012-08-01

    Full Text Available The groundwater resource contained within the sandy aquifers of the Swan Coastal Plain, south-west Western Australia, provides approximately 60 percent of the drinking water for the metropolitan population of Perth. Rainfall decline over the past three decades coupled with increasing water demand from a growing population has resulted in falling dam storage and groundwater levels. Projected future changes in climate across south-west Western Australia consistently show a decline in annual rainfall of between 5 and 15 percent. There is expected to be a reduction of diffuse recharge across the Swan Coastal Plain. This study aims to quantify the change in groundwater recharge in response to a range of future climate and land cover patterns across south-west Western Australia.

    Modelling the impact on the groundwater resource of potential climate change was achieved with a dynamically linked unsaturated/saturated groundwater model. A vertical flux manager was used in the unsaturated zone to estimate groundwater recharge using a variety of simple and complex models based on climate, land cover type (e.g. native trees, plantation, cropping, urban, wetland, soil type, and taking into account the groundwater depth.

    In the area centred on the city of Perth, Western Australia, the patterns of recharge change and groundwater level change are not consistent spatially, or consistently downward. In areas with land-use change, recharge rates have increased. Where rainfall has declined sufficiently, recharge rates are decreasing, and where compensating factors combine, there is little change to recharge. In the southwestern part of the study area, the patterns of groundwater recharge are dictated primarily by soil, geology and land cover. In the sand-dominated areas, there is little response to future climate change, because groundwater levels are shallow and much rainfall is rejected recharge. Where the combination of native vegetation and

  8. How to Recharge a Confined Aquifer: An Exploration of Geologic Controls on Groundwater Storage.

    Science.gov (United States)

    Maples, S.; Fogg, G. E.; Maxwell, R. M.; Liu, Y.

    2017-12-01

    Decreased snowpack storage and groundwater overdraft in California has increased interest in managed aquifer recharge (MAR) of excess winter runoff to the Central Valley aquifer system, which has unused storage capacity that far exceeds the state's surface reservoirs. Recharge to the productive, confined aquifer system remains a challenge due to the presence of nearly-ubiquitous, multiple silt and clay confining units that limit recharge pathways. However, previous studies have identified interconnected networks of sand and gravel deposits that bypass the confining units and accommodate rapid, high-volume recharge to the confined aquifer system in select locations. We use the variably-saturated, fully-integrated groundwater/surface-water flow code, ParFlow, in combination with a high-resolution, transition probability Markov-chain geostatistical model of the subsurface geologic heterogeneity of the east side of the Sacramento Valley, CA, to characterize recharge potential across a landscape that includes these geologic features. Multiple 180-day MAR simulations show that recharge potential is highly dependent on subsurface geologic structure, with a several order-of-magnitude range of recharge rates and volumes across the landscape. Where there are recharge pathways to the productive confined-aquifer system, pressure propagation in the confined system is widespread and rapid, with multi-kilometer lateral pressure propagation. Although widespread pressure propagation occurs in the confined system, only a small fraction of recharge volume is accommodated there. Instead, the majority of recharge occurs by filling unsaturated pore spaces. Where they outcrop at land surface, high-K recharge pathways fill rapidly, accommodating the majority of recharge during early time. However, these features become saturated quickly, and somewhat counterintuitively, the low-K silt and clay facies accommodate the majority of recharge volume during most of the simulation. These findings

  9. Tracing groundwater recharge sources in the northwestern Indian alluvial aquifer using water isotopes (δ18O, δ2H and 3H)

    Science.gov (United States)

    Joshi, Suneel Kumar; Rai, Shive Prakash; Sinha, Rajiv; Gupta, Sanjeev; Densmore, Alexander Logan; Rawat, Yadhvir Singh; Shekhar, Shashank

    2018-04-01

    Rapid groundwater depletion from the northwestern Indian aquifer system in the western Indo-Gangetic basin has raised serious concerns over the sustainability of groundwater and the livelihoods that depend on it. Sustainable management of this aquifer system requires that we understand the sources and rates of groundwater recharge, however, both these parameters are poorly constrained in this region. Here we analyse the isotopic (δ18O, δ2H and tritium) compositions of groundwater, precipitation, river and canal water to identify the recharge sources, zones of recharge, and groundwater flow in the Ghaggar River basin, which lies between the Himalayan-fed Yamuna and Sutlej River systems in northwestern India. Our results reveal that local precipitation is the main source of groundwater recharge. However, depleted δ18O and δ2H signatures at some sites indicate recharge from canal seepage and irrigation return flow. The spatial variability of δ18O, δ2H, d-excess, and tritium reflects limited lateral connectivity due to the heterogeneous and anisotropic nature of the aquifer system in the study area. The variation of tritium concentration with depth suggests that groundwater above c. 80 mbgl is generally modern water. In contrast, water from below c. 80 mbgl is a mixture of modern and old waters, and indicates longer residence time in comparison to groundwater above c. 80 mbgl. Isotopic signatures of δ18O, δ2H and tritium suggest significant vertical recharge down to a depth of 320 mbgl. The spatial and vertical variations of isotopic signature of groundwater reveal two distinct flow patterns in the aquifer system: (i) local flow (above c. 80 mbgl) throughout the study area, and (ii) intermediate and regional flow (below c. 80 mbgl), where water recharges aquifers through large-scale lateral flow as well as vertical infiltration. The understanding of spatial and vertical recharge processes of groundwater in the study area provides important base-line knowledge

  10. Using 14C and 3H to understand groundwater flow and recharge in an aquifer window

    Science.gov (United States)

    Atkinson, A. P.; Cartwright, I.; Gilfedder, B. S.; Cendón, D. I.; Unland, N. P.; Hofmann, H.

    2014-12-01

    Knowledge of groundwater residence times and recharge locations is vital to the sustainable management of groundwater resources. Here we investigate groundwater residence times and patterns of recharge in the Gellibrand Valley, southeast Australia, where outcropping aquifer sediments of the Eastern View Formation form an "aquifer window" that may receive diffuse recharge from rainfall and recharge from the Gellibrand River. To determine recharge patterns and groundwater flow paths, environmental isotopes (3H, 14C, δ13C, δ18O, δ2H) are used in conjunction with groundwater geochemistry and continuous monitoring of groundwater elevation and electrical conductivity. The water table fluctuates by 0.9 to 3.7 m annually, implying recharge rates of 90 and 372 mm yr-1. However, residence times of shallow (11 to 29 m) groundwater determined by 14C are between 100 and 10 000 years, 3H activities are negligible in most of the groundwater, and groundwater electrical conductivity remains constant over the period of study. Deeper groundwater with older 14C ages has lower δ18O values than younger, shallower groundwater, which is consistent with it being derived from greater altitudes. The combined geochemistry data indicate that local recharge from precipitation within the valley occurs through the aquifer window, however much of the groundwater in the Gellibrand Valley predominantly originates from the regional recharge zone, the Barongarook High. The Gellibrand Valley is a regional discharge zone with upward head gradients that limits local recharge to the upper 10 m of the aquifer. Additionally, the groundwater head gradients adjacent to the Gellibrand River are generally upwards, implying that it does not recharge the surrounding groundwater and has limited bank storage. 14C ages and Cl concentrations are well correlated and Cl concentrations may be used to provide a first-order estimate of groundwater residence times. Progressively lower chloride concentrations from 10

  11. Stable isotopic data for inferring source of groundwater recharge in the Anekal Taluk, Karnataka

    International Nuclear Information System (INIS)

    Ansari, Md. Arzoo; Deodhar, Archana; Jaryal, Ajay; Mendhekar, G.N.; Sinha, U.K.; Dash, Ashutosh; Davis, Deljo

    2015-01-01

    Occurrence of groundwater mainly depends on recharge area characteristics such as slope of the topography, surface cover characteristics, geology of the area and the permeability of top soil etc. Most of the tube wells located in the study area are in unconfined aquifer and the hydrology of them is mainly influenced by rainfall and surrounding catchments area characteristics. Isotope techniques provide a unique tool for establishing the recharge areas of groundwater. The stable Isotopes of O and H in water behave chemically conservative below 60 - 80°C and their concentrations are not affected by geochemical reactions in normal aquifers. Therefore, groundwater preserves its isotopic fingerprint, reflecting the history and origin before infiltration. This makes it an useful tool to interpret recharge mechanisms and the flow system. Therefore, an isotope hydrological technique has been applied in Anekal (12 deg 47 min 44 sec N; 77 deg 41 min 29 sec E) to identify the groundwater recharge area. Groundwater samples were collected from the study areas and analyzed for environmental Isotope (δ 2 H, δ 18 O) by a Isotope ratio mass spectrometer (IsoPrime-100) using gas equilibration method. Physico-chemical parameters (Temperature, EC, pH) were measured insitu. Electrical conductivity (EC) of the groundwater ranges from 668 to 2139 μS/cm, which is dependent on their travel path and the associated rock-water interaction (dissolution of rock minerals)

  12. Stable isotope and groundwater flow dynamics of agricultural irrigation recharge into groundwater resources of the Central Valley, California

    International Nuclear Information System (INIS)

    Davisson, M.L.; Criss, R.E.

    1995-01-01

    Intensive agricultural irrigation and overdraft of groundwater in the Central Valley of California profoundly affect the regional quality and availability of shallow groundwater resources. In the natural state, the δ 18 O values of groundwater were relatively homogeneous (mostly -7.0 ± 0.5 per-thousand), reflecting local meteoric recharge that slowly (1-3m/yr) flowed toward the valley axis. Today, on the west side of the valley, the isotope distribution is dominated by high 18 O enclosures formed by recharge of evaporated irrigation waters, while the east side has bands of low 18 O groundwater indicating induced recharge from rivers draining the Sierra Nevada mountains. Changes in δ 18 O values caused by the agricultural recharge strongly correlate with elevated nitrate concentrations (5 to >100 mg/L) that form pervasive, non-point source pollutants. Small, west-side cities dependent solely on groundwater resources have experienced increases of >1.0 mg/L per year of nitrate for 10-30 years. The resultant high nitrates threaten the economical use of the groundwater for domestic purposes, and have forced some well shut-downs. Furthermore, since >80% of modern recharge is now derived from agricultural irrigation, and because modern recharge rates are ∼10 times those of the natural state, agricultural land retirement by urbanization will severely curtail the current safe-yields and promote overdraft pumping. Such overdrafting has occurred in the Sacramento metropolitan area for ∼40 years, creating cones of depression ∼25m deep. Today, groundwater withdrawal in Sacramento is approximately matched by infiltration of low 18 O water (-11.0 per-thousand) away from the Sacramento and American Rivers, which is estimated to occur at 100-300m/year from the sharp 18 O gradients in our groundwater isotope map

  13. Potential groundwater recharge for the State of Minnesota using the Soil-Water-Balance model, 1996-2010

    Science.gov (United States)

    Smith, Erik A.; Westenbroek, Stephen M.

    2015-01-01

    Groundwater recharge is one of the most difficult components of a water budget to ascertain, yet is an important boundary condition necessary for the quantification of water resources. In Minnesota, improved estimates of recharge are necessary because approximately 75 percent of drinking water and 90 percent of agricultural irrigation water in Minnesota are supplied from groundwater. The water that is withdrawn must be supplied by some combination of (1) increased recharge, (2) decreased discharge to streams, lakes, and other surface-water bodies, and (3) removal of water that was stored in the system. Recent pressure on groundwater resources has highlighted the need to provide more accurate recharge estimates for various tools that can assess the sustainability of long-term water use. As part of this effort, the U.S. Geological Survey, in cooperation with the Minnesota Pollution Control Agency, used the Soil-Water-Balance model to calculate gridded estimates of potential groundwater recharge across Minnesota for 1996‒2010 at a 1-kilometer (0.621-mile) resolution. The potential groundwater recharge estimates calculated for Minnesota from the Soil-Water Balance model included gridded values (1-kilometer resolution) of annual mean estimates (that is, the means for individual years from 1996 through 2010) and mean annual estimates (that is, the mean for the 15-year period 1996−2010).

  14. Estimation of groundwater recharge to chalk and sandstone aquifers using simple soil models

    Science.gov (United States)

    Ragab, R.; Finch, J.; Harding, R.

    1997-03-01

    On the assumption that the water draining below the root zone is potentially available for groundwater recharge, two current UK methods for estimating annual groundwater recharge have been compared with a new soil model using data from four sites under permanent grass in the UK: two sites representative of the Chalk aquifer at Bridgest Farm (Hampshire) and Fleam Dyke (Cambridgeshire), and two sites on the Triassic sandstone at Bicton College (Devon) and Bacon Hall (Shropshire). A Four Root Layers Model (FRLM), the Penman-Grindley model and the UK Meteorological Office Rainfall and Evaporation Calculation System (MORECS) were used. The new soil model was run with potential evaporation as input both from the MORECS and from the Penman-Monteith equation. The models were run for the Chalk sites both with and without a bypass flow of 15% of rainfall. Bypass was not considered for the sandstone sites. The performance of the models was tested against neutron probes measurements of soil moisture deficits. In addition, the annual groundwater recharge estimated from the models was compared with the published values obtained from the 'zero flux plane' method. Generally, the Penman-Grindley model was more successful in predicting the time for soil to return to its field capacity than in predicting the magnitude of the soil moisture deficit. The annual groundwater recharge was predicted with reasonable accuracy. The MORECS relatively tended to overestimate the soil moisture deficits and to delay the time at which the soil returns to its field capacity. The consequences were underestimates of annual groundwater recharge, owing either to the higher values of potential evaporation calculated from the MORECS or tothe high available water capacity values associated with the soils under consideration. The new soil model (FRLM) predicts the soil moisture deficits successfully and hence is reliable in estimating the annual groundwater recharge. The model is capable of doing this with

  15. Bacterial community and groundwater quality changes in an anaerobic aquifer during groundwater recharge with aerobic recycled water.

    Science.gov (United States)

    Ginige, Maneesha P; Kaksonen, Anna H; Morris, Christina; Shackelton, Mark; Patterson, Bradley M

    2013-09-01

    Managed aquifer recharge offers the opportunity to manage groundwater resources by storing water in aquifers when in surplus and thus increase the amount of groundwater available for abstraction during high demand. The Water Corporation of Western Australia (WA) is undertaking a Groundwater Replenishment Trial to evaluate the effects of recharging aerobic recycled water (secondary treated wastewater subjected to ultrafiltration, reverse osmosis, and ultraviolet disinfection) into the anaerobic Leederville aquifer in Perth, WA. Using culture-independent methods, this study showed the presence of Actinobacteria, Alphaproteobacteria, Bacilli, Betaproteobacteria, Cytophaga, Flavobacteria, Gammaproteobacteria, and Sphingobacteria, and a decrease in microbial diversity with an increase in depth of aquifer. Assessment of physico-chemical and microbiological properties of groundwater before and after recharge revealed that recharging the aquifer with aerobic recycled water resulted in elevated redox potentials in the aquifer and increased bacterial numbers, but reduced microbial diversity. The increase in bacterial numbers and reduced microbial diversity in groundwater could be a reflection of an increased denitrifier and sulfur-oxidizing populations in the aquifer, as a result of the increased availability of nitrate, oxygen, and residual organic matter. This is consistent with the geochemical data that showed pyrite oxidation and denitrification within the aquifer after recycled water recharge commenced. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  16. Geophysical Methods for Investigating Ground-Water Recharge

    Science.gov (United States)

    Ferre, Ty P.A.; Binley, Andrew M.; Blasch, Kyle W.; Callegary, James B.; Crawford, Steven M.; Fink, James B.; Flint, Alan L.; Flint, Lorraine E.; Hoffmann, John P.; Izbicki, John A.; Levitt, Marc T.; Pool, Donald R.; Scanlon, Bridget R.

    2007-01-01

    While numerical modeling has revolutionized our understanding of basin-scale hydrologic processes, such models rely almost exclusively on traditional measurements?rainfall, streamflow, and water-table elevations?for calibration and testing. Model calibration provides initial estimates of ground-water recharge. Calibrated models are important yet crude tools for addressing questions about the spatial and temporal distribution of recharge. An inverse approach to recharge estimation is taken of necessity, due to inherent difficulties in making direct measurements of flow across the water table. Difficulties arise because recharging fluxes are typically small, even in humid regions, and because the location of the water table changes with time. Deep water tables in arid and semiarid regions make recharge monitoring especially difficult. Nevertheless, recharge monitoring must advance in order to improve assessments of ground-water recharge. Improved characterization of basin-scale recharge is critical for informed water-resources management. Difficulties in directly measuring recharge have prompted many efforts to develop indirect methods. The mass-balance approach of estimating recharge as the residual of generally much larger terms has persisted despite the use of increasing complex and finely gridded large-scale hydrologic models. Geophysical data pertaining to recharge rates, timing, and patterns have the potential to substantially improve modeling efforts by providing information on boundary conditions, by constraining model inputs, by testing simplifying assumptions, and by identifying the spatial and temporal resolutions needed to predict recharge to a specified tolerance in space and in time. Moreover, under certain conditions, geophysical measurements can yield direct estimates of recharge rates or changes in water storage, largely eliminating the need for indirect measures of recharge. This appendix presents an overview of physically based, geophysical methods

  17. Quantifying Potential Groundwater Recharge In South Texas

    Science.gov (United States)

    Basant, S.; Zhou, Y.; Leite, P. A.; Wilcox, B. P.

    2015-12-01

    Groundwater in South Texas is heavily relied on for human consumption and irrigation for food crops. Like most of the south west US, woody encroachment has altered the grassland ecosystems here too. While brush removal has been widely implemented in Texas with the objective of increasing groundwater recharge, the linkage between vegetation and groundwater recharge in South Texas is still unclear. Studies have been conducted to understand plant-root-water dynamics at the scale of plants. However, little work has been done to quantify the changes in soil water and deep percolation at the landscape scale. Modeling water flow through soil profiles can provide an estimate of the total water flowing into deep percolation. These models are especially powerful with parameterized and calibrated with long term soil water data. In this study we parameterize the HYDRUS soil water model using long term soil water data collected in Jim Wells County in South Texas. Soil water was measured at every 20 cm intervals up to a depth of 200 cm. The parameterized model will be used to simulate soil water dynamics under a variety of precipitation regimes ranging from well above normal to severe drought conditions. The results from the model will be compared with the changes in soil moisture profile observed in response to vegetation cover and treatments from a study in a similar. Comparative studies like this can be used to build new and strengthen existing hypotheses regarding deep percolation and the role of soil texture and vegetation in groundwater recharge.

  18. Water balance-based estimation of groundwater recharge in the Lake Chad Basin

    Science.gov (United States)

    Babamaaji, R. A.; Lee, J.

    2012-12-01

    Lake Chad Basin (LCB) has experienced drastic changes of land cover and poor water management practices during the last 50 years. The successive droughts in the 1970s and 1980s resulted in the shortage of surface water and groundwater resources. This problem of drought and shortage of water has a devastating implication on the natural resources of the Basin with great consequence on food security, poverty reduction and quality of life of the inhabitants in the LCB. Therefore, understanding the change of land use and its characteristics must be a first step to find how such changes disturb the water cycle especially the groundwater in the LCB. The abundance of groundwater is affected by the climate change through the interaction with surface water, such as lakes and rivers, and vertical recharge through an infiltration process. Quantifying the impact of climate change on the groundwater resource requires not only reliable forecasting of changes in the major climatic variables, but also accurate estimation of groundwater recharge. Spatial variations in the land use/land cover, soil texture, topographic slope, and meteorological conditions should be accounted for in the recharge estimation. In this study, we employed a spatially distributed water balance model WetSpass to simulate a long-term average change of groundwater recharge in the LCB of Africa. WetSpass is a water balance-based model to estimate seasonal average spatial distribution of surface runoff, evapotranspiration, and groundwater recharge. The model is especially suitable for studying the effect of land use/land cover change on the water regime in the LCB. The present study describes the concept of the model and its application to the development of recharge map of the LCB.

  19. Estimation of Groundwater Recharge in a Japanese Headwater Area by Intensive Collaboration of Field Survey and Modelling Work

    Science.gov (United States)

    Yano, S.; Kondo, H.; Tawara, Y.; Yamada, T.; Mori, K.; Yoshida, A.; Tada, K.; Tsujimura, M.; Tokunaga, T.

    2017-12-01

    It is important to understand groundwater systems, including their recharge, flow, storage, discharge, and withdrawal, so that we can use groundwater resources efficiently and sustainably. To examine groundwater recharge, several methods have been discussed based on water balance estimation, in situ experiments, and hydrological tracers. However, few studies have developed a concrete framework for quantifying groundwater recharge rates in an undefined area. In this study, we established a robust method to quantitatively determine water cycles and estimate the groundwater recharge rate by combining the advantages of field surveys and model simulations. We replicated in situ hydrogeological observations and three-dimensional modeling in a mountainous basin area in Japan. We adopted a general-purpose terrestrial fluid-flow simulator (GETFLOWS) to develop a geological model and simulate the local water cycle. Local data relating to topology, geology, vegetation, land use, climate, and water use were collected from the existing literature and observations to assess the spatiotemporal variations of the water balance from 2011 to 2013. The characteristic structures of geology and soils, as found through field surveys, were parameterized for incorporation into the model. The simulated results were validated using observed groundwater levels and resulted in a Nash-Sutcliffe Model Efficiency Coefficient of 0.92. The results suggested that local groundwater flows across the watershed boundary and that the groundwater recharge rate, defined as the flux of water reaching the local unconfined groundwater table, has values similar to the level estimated in the `the lower soil layers on a long-term basis. This innovative method enables us to quantify the groundwater recharge rate and its spatiotemporal variability with high accuracy, which contributes to establishing a foundation for sustainable groundwater management.

  20. Effect of temporal averaging of meteorological data on predictions of groundwater recharge

    Directory of Open Access Journals (Sweden)

    Batalha Marcia S.

    2018-06-01

    Full Text Available Accurate estimates of infiltration and groundwater recharge are critical for many hydrologic, agricultural and environmental applications. Anticipated climate change in many regions of the world, especially in tropical areas, is expected to increase the frequency of high-intensity, short-duration precipitation events, which in turn will affect the groundwater recharge rate. Estimates of recharge are often obtained using monthly or even annually averaged meteorological time series data. In this study we employed the HYDRUS-1D software package to assess the sensitivity of groundwater recharge calculations to using meteorological time series of different temporal resolutions (i.e., hourly, daily, weekly, monthly and yearly averaged precipitation and potential evaporation rates. Calculations were applied to three sites in Brazil having different climatological conditions: a tropical savanna (the Cerrado, a humid subtropical area (the temperate southern part of Brazil, and a very wet tropical area (Amazonia. To simplify our current analysis, we did not consider any land use effects by ignoring root water uptake. Temporal averaging of meteorological data was found to lead to significant bias in predictions of groundwater recharge, with much greater estimated recharge rates in case of very uneven temporal rainfall distributions during the year involving distinct wet and dry seasons. For example, at the Cerrado site, using daily averaged data produced recharge rates of up to 9 times greater than using yearly averaged data. In all cases, an increase in the time of averaging of meteorological data led to lower estimates of groundwater recharge, especially at sites having coarse-textured soils. Our results show that temporal averaging limits the ability of simulations to predict deep penetration of moisture in response to precipitation, so that water remains in the upper part of the vadose zone subject to upward flow and evaporation.

  1. Tracers Reveal Recharge Elevations, Groundwater Flow Paths and Travel Times on Mount Shasta, California

    Directory of Open Access Journals (Sweden)

    Elizabeth Peters

    2018-01-01

    Full Text Available Mount Shasta (4322 m is famous for its spring water. Water for municipal, domestic and industrial use is obtained from local springs and wells, fed by annual snow melt and sustained perennially by the groundwater flow system. We examined geochemical and isotopic tracers in samples from wells and springs on Mount Shasta, at the headwaters of the Sacramento River, in order to better understand the hydrologic system. The topographic relief in the study area imparts robust signatures of recharge elevation to both stable isotopes of the water molecule (δ18O and δD and to dissolved noble gases, offering tools to identify recharge areas and delineate groundwater flow paths. Recharge elevations determined using stable isotopes and noble gas recharge temperatures are in close agreement and indicate that most snowmelt infiltrates at elevations between 2000 m and 2900 m, which coincides with areas of thin soils and barren land cover. Large springs in Mt Shasta City discharge at an elevation more than 1600 m lower. High elevation springs (>2000 m yield very young water (<2 years while lower elevation wells (1000–1500 m produce water with a residence time ranging from 6 years to over 60 years, based on observed tritium activities. Upslope movement of the tree line in the identified recharge elevation range due to a warming climate is likely to decrease infiltration and recharge, which will decrease spring discharge and production at wells, albeit with a time lag dependent upon the length of groundwater flow paths.

  2. Inverse modeling and uncertainty analysis of potential groundwater recharge to the confined semi-fossil Ohangwena II Aquifer, Namibia

    Science.gov (United States)

    Wallner, Markus; Houben, Georg; Lohe, Christoph; Quinger, Martin; Himmelsbach, Thomas

    2017-12-01

    The identification of potential recharge areas and estimation of recharge rates to the confined semi-fossil Ohangwena II Aquifer (KOH-2) is crucial for its future sustainable use. The KOH-2 is located within the endorheic transboundary Cuvelai-Etosha-Basin (CEB), shared by Angola and Namibia. The main objective was the development of a strategy to tackle the problem of data scarcity, which is a well-known problem in semi-arid regions. In a first step, conceptual geological cross sections were created to illustrate the possible geological setting of the system. Furthermore, groundwater travel times were estimated by simple hydraulic calculations. A two-dimensional numerical groundwater model was set up to analyze flow patterns and potential recharge zones. The model was optimized against local observations of hydraulic heads and groundwater age. The sensitivity of the model against different boundary conditions and internal structures was tested. Parameter uncertainty and recharge rates were estimated. Results indicate that groundwater recharge to the KOH-2 mainly occurs from the Angolan Highlands in the northeastern part of the CEB. The sensitivity of the groundwater model to different internal structures is relatively small in comparison to changing boundary conditions in the form of influent or effluent streams. Uncertainty analysis underlined previous results, indicating groundwater recharge originating from the Angolan Highlands. The estimated recharge rates are less than 1% of mean yearly precipitation, which are reasonable for semi-arid regions.

  3. Intermediate tree cover can maximize groundwater recharge in the seasonally dry tropics

    Science.gov (United States)

    Ilstedt, U.; Bargués Tobella, A.; Bazié, H. R.; Bayala, J.; Verbeeten, E.; Nyberg, G.; Sanou, J.; Benegas, L.; Murdiyarso, D.; Laudon, H.; Sheil, D.; Malmer, A.

    2016-01-01

    Water scarcity contributes to the poverty of around one-third of the world’s people. Despite many benefits, tree planting in dry regions is often discouraged by concerns that trees reduce water availability. Yet relevant studies from the tropics are scarce, and the impacts of intermediate tree cover remain unexplored. We developed and tested an optimum tree cover theory in which groundwater recharge is maximized at an intermediate tree density. Below this optimal tree density the benefits from any additional trees on water percolation exceed their extra water use, leading to increased groundwater recharge, while above the optimum the opposite occurs. Our results, based on groundwater budgets calibrated with measurements of drainage and transpiration in a cultivated woodland in West Africa, demonstrate that groundwater recharge was maximised at intermediate tree densities. In contrast to the prevailing view, we therefore find that moderate tree cover can increase groundwater recharge, and that tree planting and various tree management options can improve groundwater resources. We evaluate the necessary conditions for these results to hold and suggest that they are likely to be common in the seasonally dry tropics, offering potential for widespread tree establishment and increased benefits for hundreds of millions of people. PMID:26908158

  4. Estimating groundwater recharge in the outcrop area of the Guarani Aquifer System; Estimativa de recarga subterranea en area de afloramento do Sistema Aquifero Guarani

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, M. C.; Guanabara, R. C.; Wendland, E.

    2012-11-01

    The Guarani aquifer system (GAS) is one of the most important groundwater reservoirs in South America. Its main groundwater recharge occurs in the outcrop areas of the Botucatu and Piramboia formations. In these areas groundwater input, such as the infiltration of precipitation, is controlled mainly by climatic characteristics, soil proprieties and land use in the area. We provide here an estimation of the annual recharge into the Ribeirao da Onca basin, located in an outcrop area of the GAS, resulting from data collected during monitoring from September 2004 until August 2011. Fluctuations in the water table were measured at 11 piezometers, sited in different crops areas. Processing techniques for multispectral images were used to map land use. Recharge was estimated by a local-scale method (water-table fluctuation, WTF). Recharge estimates for areas with citrus and eucalyptus proved to be lower than for areas under grassland and sugar cane. Annual recharge rates estimated for the entire watershed ranged from 80 mm to 359 mm for annual precipitations of 1,175.5 mm and 1,807.7 mm. The assessment of recharge in outcrop areas is essential for a suitable future exploitation of the GAS. (Author)

  5. Analyses of infrequent (quasi-decadal) large groundwater recharge events in the northern Great Basin: Their importance for groundwater availability, use, and management

    Science.gov (United States)

    Masbruch, Melissa D.; Rumsey, Christine; Gangopadhyay, Subhrendu; Susong, David D.; Pruitt, Tom

    2016-01-01

    There has been a considerable amount of research linking climatic variability to hydrologic responses in the western United States. Although much effort has been spent to assess and predict changes in surface water resources, little has been done to understand how climatic events and changes affect groundwater resources. This study focuses on characterizing and quantifying the effects of large, multiyear, quasi-decadal groundwater recharge events in the northern Utah portion of the Great Basin for the period 1960–2013. Annual groundwater level data were analyzed with climatic data to characterize climatic conditions and frequency of these large recharge events. Using observed water-level changes and multivariate analysis, five large groundwater recharge events were identified with a frequency of about 11–13 years. These events were generally characterized as having above-average annual precipitation and snow water equivalent and below-average seasonal temperatures, especially during the spring (April through June). Existing groundwater flow models for several basins within the study area were used to quantify changes in groundwater storage from these events. Simulated groundwater storage increases per basin from a single recharge event ranged from about 115 to 205 Mm3. Extrapolating these amounts over the entire northern Great Basin indicates that a single large quasi-decadal recharge event could result in billions of cubic meters of groundwater storage. Understanding the role of these large quasi-decadal recharge events in replenishing aquifers and sustaining water supplies is crucial for long-term groundwater management.

  6. Impacts of vegetation change on groundwater recharge

    Science.gov (United States)

    Bond, W. J.; Verburg, K.; Smith, C. J.

    2003-12-01

    Vegetation change is the accepted cause of increasing river salt concentrations and the salinisation of millions of hectares of farm land in Australia. Replacement of perennial native vegetation by annual crops and pastures following European settlement has altered the water balance causing increased groundwater recharge and mobilising the naturally saline groundwater. The Redesigning Agriculture for Australian Landscapes Program, of which the work described here is a part, was established to develop agricultural practices that are more attuned to the delicate water balance described above. Results of field measurements will be presented that contrast the water balance characteristics of native vegetation with those of conventional agricultural plants, and indicate the functional characteristics required of new agricultural practices to reduce recharge. New agricultural practices may comprise different management of current crops and pastures, or may involve introducing totally new species. In either case, long-term testing is required to examine their impact on recharge over a long enough climate record to encompass the natural variability of rainfall that is characteristic of most Australian farming regions. Field experimentation therefore needs to be complemented and extended by computer simulation. This requires a modelling approach that is more robust than conventional crop modelling because (a) it needs to be sensitive enough to predict small changes in the residual recharge term, (b) it needs to be able to simulate a variety of vegetation in different sequences, (c) it needs to be able to simulate continuously for several decades of input data, and (d) it therefore needs to be able to simulate the period between crops, which often has a critical impact on recharge. The APSIM simulation framework will be used to illustrate these issues and to explore the effect of different vegetation combinations on recharge.

  7. Radioecological aspects in artificial groundwater recharge

    Energy Technology Data Exchange (ETDEWEB)

    Matthess, G [Kiel Univ. (Germany, F.R.). Geologisch-Palaeontologisches Inst. und Museum; Neumayr, V [Institut fuer Wasser-, Boden- und Lufthygiene, Frankfurt am Main (Germany, F.R.)

    1980-01-01

    In increasing extent surface waters, especially those of rivers and streams, are contaminated by radionuclides. Therefore it is necessary to investigate the possibility of impairment of the quality of artificially recharged groundwater and drinking water by radionuclides. Hazards for man are possible by drinking water, that was affected by waste and during exposition to air, as well as indirectly by irrigation water and the food chain. In a model calculation using realistic conditions the order of magnitude of these hazards for man by incorporation of radioactively contaminated artificially recharged drinking water are to be assessed. Here the parameters are discussed which must be considered in such an assessment. The model includes the use of river water for artificial recharge. All models and assessments assume the most unfavourable preconditions, which may lead to an impact to man.

  8. Groundwater recharge in Wisconsin--Annual estimates for 1970-99 using streamflow data

    Science.gov (United States)

    Gebert, Warren A.; Walker, John F.; Hunt, Randall J.

    2011-01-01

    The groundwater component of streamflow is important because it is indicative of the sustained flow of a stream during dry periods, is often of better quality, and has a smaller range of temperatures, than surface contributions to streamflow. All three of these characteristics are important to the health of aquatic life in a stream. If recharge to the aquifers is to be preserved or enhanced, it is important to understand the present partitioning of total streamflow into base flow and stormflow. Additionally, an estimate of groundwater recharge is important for understanding the flows within a groundwater system-information important for water availability/sustainability or other assessments. The U.S. Geological Survey operates numerous continuous-record streamflow-gaging stations (Hirsch and Norris, 2001), which can be used to provide estimates of average annual base flow. In addition to these continuous record sites, Gebert and others (2007) showed that having a few streamflow measurements in a basin can appreciably reduce the error in a base-flow estimate for that basin. Therefore, in addition to the continuous-record gaging stations, a substantial number of low-flow partial-record sites (6 to 15 discharge measurements) and miscellaneous-measurement sites (1 to 3 discharge measurements) that were operated during 1964-90 throughout the State were included in this work to provide additional insight into spatial distribution of annual base flow and, in turn, groundwater recharge.

  9. Comparative study of irrigation water use and groundwater recharge under various irrigation schemes in an agricultural region, central Taiwan

    Science.gov (United States)

    Chen, Shih-Kai; Jang, Cheng-Shin; Tsai, Cheng-Bin

    2016-04-01

    The risk of rice production has increased notably due to climate change in Taiwan. To respond to growing agricultural water shortage without affecting normal food production in the future, the application of water-saving irrigation will be a substantial resolution. However, the adoption of water-saving irrigation may result in the reducing of groundwater recharge because continuous flooding in the paddy fields could be regarded as an important source for groundwater recharge. The aim of this study was to evaluate the irrigation water-saving benefit and groundwater recharge deficit when adopting the System of Rice Intensification, known as SRI methodology, in the Choushui River alluvial fan (the largest groundwater pumping and the most important rice-cropping region in central Taiwan). The three-dimensional finite element groundwater model, FEMWATER, was applied to simulate the infiltration process and groundwater recharge under SRI methodology and traditional irrigation schemes including continuous irrigation, and rotational irrigation in two rice-crop periods with hydro-climatic data of 2013. The irrigation water use was then calculated by water balance. The results showed that groundwater recharge amount of SRI methodology was slightly lower than those of traditional irrigation schemes, reduced 3.6% and 1.6% in the first crop period, and reduced 3.2% and 1.6% in the second crop period, compared with continuous irrigation and rotational irrigation, respectively. However, the SRI methodology achieved notably water-saving benefit compared to the disadvantage of reducing the groundwater recharge amount. The field irrigation requirement amount of SRI methodology was significantly lower than those of traditional irrigation schemes, saving 37% and 20% of irrigation water in the first crop period, and saving 53% and 35% in the second crop period, compared with continuous irrigation and rotational irrigation, respectively. Therefore, the amount of groundwater pumping for

  10. Groundwater recharge estimates of the Indian Wells Basin (California) using geochemical analysis of tritium

    Science.gov (United States)

    Faulkner, K. E.; Hagedorn, K. B.

    2017-12-01

    Quantifying recharge in groundwater basins located in an arid climate is difficult due to the effects of evapotranspiration and generally low rates of inflow. Constraining recharge for the Indian Wells Valley (IWV) will allow a more refined assessment of groundwater sustainability in the basin. In this study, a well-mixed reservoir model, the decay rate of tritium, groundwater tritium data acquired from USGS, and atmospheric tritium data acquired from IAEA allow for calculation of renewal rate within IWV. The resulting renewal rate throughout the basin show correlation to travel time from the source of recharge to the measurement location in keeping with the well-mixed reservoir model. The renewal rate can be used with porosity and effective aquifer thickness to generate recharge rates ranging from 4.7 cm/yr to 10 cm/yr. Refinement of the porosity and effective aquifer thickness values at each sample location is necessary to constrain recharge rates. Groundwater modeling generated recharge rates (9.32 cm/yr) fall within this range. These results are in keeping with the well-mixed aquifer model and fall within a reasonable range for an arid climate, which shows the applicability of the method.

  11. Evaluation of drought impact on groundwater recharge rate using SWAT and Hydrus models on an agricultural island in western Japan

    Directory of Open Access Journals (Sweden)

    G. Jin

    2015-06-01

    Full Text Available Clarifying the variations of groundwater recharge response to a changing non-stationary hydrological process is important for efficiently managing groundwater resources, particularly in regions with limited precipitation that face the risk of water shortage. However, the rate of aquifer recharge is difficult to evaluate in terms of large annual-variations and frequency of flood events. In our research, we attempt to simulate related groundwater recharge processes under variable climate conditions using the SWAT Model, and validate the groundwater recharge using the Hydrus Model. The results show that annual average groundwater recharge comprised approximately 33% of total precipitation, however, larger variation was found for groundwater recharge and surface runoff compared to evapotranspiration, which fluctuated with annual precipitation variations. The annual variation of groundwater resources is shown to be related to precipitation. In spatial variations, the upstream is the main surface water discharge area; the middle and downstream areas are the main groundwater recharge areas. Validation by the Hydrus Model shows that the estimated and simulated groundwater levels are consistent in our research area. The groundwater level shows a quick response to the groundwater recharge rate. The rainfall intensity had a great impact on the changes of the groundwater level. Consequently, it was estimated that large spatial and temporal variation of the groundwater recharge rate would be affected by precipitation uncertainty in future.

  12. Groundwater recharge mechanism in an integrated tableland of the Loess Plateau, northern China: insights from environmental tracers

    Science.gov (United States)

    Huang, Tianming; Pang, Zhonghe; Liu, Jilai; Ma, Jinzhu; Gates, John

    2017-11-01

    Assessing groundwater recharge characteristics (recharge rate, history, mechanisms (piston and preferential flow)) and groundwater age in arid and semi-arid environments remains a difficult but important research frontier. Such assessments are particularly important when the unsaturated zone (UZ) is thick and the recharge rate is limited. This study combined evaluations of the thick UZ with those of the saturated zone and used multiple tracers, such as Cl, NO3, Br, 2H, 18O, 13C, 3H and 14C, to study groundwater recharge characteristics in an integrated loess tableland in the Loess Plateau, China, where precipitation infiltration is the only recharge source for shallow groundwater. The results indicate that diffuse recharge beneath crops, as the main land use of the study area, is 55-71 mm yr-1 based on the chloride mass balance of soil profiles. The length of time required for annual precipitation to reach the water table is 160-400 yrs. The groundwater is all pre-modern water and paleowater, with corrected 14C age ranging from 136 to 23,412 yrs. Most of the water that eventually becomes recharge originally infiltrated in July-September. The Cl and NO3 contents in the upper UZ are considerably higher than those in the deep UZ and shallow groundwater because of recent human activities. The shallow groundwater has not been in hydraulic equilibrium with present near-surface boundary conditions. The homogeneous material of the UZ and relatively old groundwater age imply that piston flow is the dominant recharge mechanism for the shallow groundwater in the tableland.

  13. Groundwater recharge and agricultural contamination in alluvial fan of Eastern Kofu basin, JAPAN

    Science.gov (United States)

    Nakamura, T.

    2009-12-01

    Agriculture has significant effects on the rate and composition of groundwater recharge. The chemical loading into groundwater have been dominated by the constituents derived directly or indirectly from agricultural practices and additives. The contamination of groundwater with nitrate is a major public health and environmental concern around the world. The inorganic constituents like, K+, Ca2+, Mg2+, SO42-, Cl- and variety of other minor elements of groundwater are often used as agricultural additives; and the natural occurrence of these elements are dominated by the agricultural sources. A recent study has reported that Kofu basin groundwater aquifer is contaminated by nitrate from agricultural areas because of the fertilizer application for the orchard (Kazama and Yoneyama, 2002; Sakamoto et al., 1997, Nakamura et al., 2007). The water-oxygen and hydrogen stable isotope (δ18O and δD) and nitrate-nitrogen stable isotope (δ15N) of groundwater, river water and precipitation samples were investigated to identify the source of groundwater and nitrate nitrogen contamination in groundwater in the Fuefukigawa and Hikawa_Kanegawa alluvial fans in Kofu basin. The plot of δD versus δ18O values of groundwater, river water and precipitation samples suggest that the groundwater is a mixture of precipitation and river water. And nitrate-nitrogen isotope values have suggested the nitrate contamination of groundwater is from agricultural area. The study revealed positive correlation between groundwater δ18O values and NO3-, Cl-, SO42-, Ca2+, Mg2+ concentration, which shows the agricultural contamination is carried by the recharge of groundwater from precipitation in alluvial fan. Whereas, NO3-, Cl-, SO42-, Ca2+, Mg2+ are diluted by the river water recharges. This study showed the quality of groundwater is resulted from the mixing of water from the different source during the groundwater recharge in the study area. References Kazama F, Yoneyama M (2002) Nitrogen generation

  14. Soil and geologic controls on recharge and groundwater flow response to climate perturbation: A case study of the Yakima River Basin

    Science.gov (United States)

    Nguyen, T. T.; Pham, H. V.; Bachmann, M.; Tague, C.; Adam, J. C.

    2017-12-01

    The Yakima River Basin (YRB) is one of the most important agricultural basins in Washington State with annual revenues in excess of $3.2 billion. This intensively irrigated basin is, however, one of the state's most climatically sensitive water resources system as it heavily relies on winter snowpack and limited reservoir storage. Water shortages and drought are expected to be more frequent with climate change, population growth and increasing agricultural demand. This could result in significant impacts on the groundwater system and subsequently the Yakima River. The goal of this study is to assess how soil and geologic characteristics affect catchment recharge and groundwater flow across three catchments within the YRB using a coupled framework including a physically based hydro-ecological model, the Regional Hydro-Ecologic Simulation System (RHESSys) and a groundwater model, MODFLOW. Soil and geologic-related parameters were randomly sampled to use within the Distributed Evaluation of Local Sensitivity Analysis (DELSA) framework to explore their roles in governing catchment recharge and groundwater flow to climate perturbation. Preliminarily results show that catchment recharge is most sensitive to variation in soil transmissivity in two catchments. However, in the other catchment, recharge is more influenced by soil field capacity and bypass recharge. Recharge is also more sensitive to geologic related parameters in catchments where a portion of its flow comes from deep groundwater. When including the effect of climate perturbations, the sensitivity of recharge responses to soil and geologic characteristics varies with temperature and precipitation change. On the other hand, horizontal hydraulic conductivity is the dominant factor that controls groundwater flow responses in catchments with low permeability soil; alternatively, specific storage (and, to some extent, vertical anisotropy) are important in catchments with more conductive soil. The modeling

  15. Partitioning sources of recharge in environments with groundwater recirculation using carbon-14 and CFC-12

    Science.gov (United States)

    Bourke, Sarah A.; Cook, Peter G.; Dogramaci, Shawan; Kipfer, Rolf

    2015-06-01

    Groundwater recirculation occurs when groundwater is pumped from an aquifer onto the land surface, and a portion of that water subsequently infiltrates back to the aquifer. In environments where groundwater is recirculated, differentiation between various sources of recharge (e.g. natural rainfall recharge vs. recirculated water) can be difficult. Groundwater age indicators, in particular transient trace gases, are likely to be more sensitive tracers of recharge than stable isotopes or chloride in this setting. This is because, unlike stable isotopes or chloride, they undergo a process of equilibration with the atmosphere, and historical atmospheric concentrations are known. In this paper, groundwater age indicators (14C and CFC-12) were used as tracers of recharge by surplus mine water that is discharged to streams. Ternary mixing ratios were calculated based on 14C and CFC-12 concentrations measured along three transects of piezometers and monitoring wells perpendicular to the creeks, and from dewatering wells. Uncertainty in calculated mixing ratios was estimated using a Monte Carlo approach. Ternary mixing ratios in dewatering wells suggest that recharge by mine water accounted for between 10% and 87% of water currently abstracted by dewatering wells. The calculated mixing ratios suggest that recharge by mine water extends to a distance of more than 550 m from the creeks. These results are supported by seepage flux estimates based on the water and chloride balance along the creeks, which suggest that 85-90% of mine water discharged to the creeks recharges the aquifer and recharge by mine water extends between 110 and 730 m from the creeks. Mixing calculations based on gaseous groundwater age indicators could also be used to partition recharge associated with agricultural irrigation or artificial wetland supplementation.

  16. Comparison of groundwater recharge estimation techniques in an alluvial aquifer system with an intermittent/ephemeral stream (Queensland, Australia)

    Science.gov (United States)

    King, Adam C.; Raiber, Matthias; Cox, Malcolm E.; Cendón, Dioni I.

    2017-09-01

    This study demonstrates the importance of the conceptual hydrogeological model for the estimation of groundwater recharge rates in an alluvial system interconnected with an ephemeral or intermittent stream in south-east Queensland, Australia. The losing/gaining condition of these streams is typically subject to temporal and spatial variability, and knowledge of these hydrological processes is critical for the interpretation of recharge estimates. Recharge rate estimates of 76-182 mm/year were determined using the water budget method. The water budget method provides useful broad approximations of recharge and discharge fluxes. The chloride mass balance (CMB) method and the tritium method were used on 17 and 13 sites respectively, yielding recharge rates of 1-43 mm/year (CMB) and 4-553 mm/year (tritium method). However, the conceptual hydrogeological model confirms that the results from the CMB method at some sites are not applicable in this setting because of overland flow and channel leakage. The tritium method was appropriate here and could be applied to other alluvial systems, provided that channel leakage and diffuse infiltration of rainfall can be accurately estimated. The water-table fluctuation (WTF) method was also applied to data from 16 bores; recharge estimates ranged from 0 to 721 mm/year. The WTF method was not suitable where bank storage processes occurred.

  17. Mechanisms, timing and quantities of recharge to groundwater in semi-arid and tropical regions

    International Nuclear Information System (INIS)

    Edmunds, W.M.

    2001-01-01

    Groundwater being exploited in many and and semi-arid regions at the present day was recharged during former humid episodes of the Pleistocene or Holocene and, in contrast, the amounts derived from modem recharge are small generally small and variable. Geochemical and isotopic techniques provide the most effective way to calculate modem recharge and to investigate recharge history, since physically- based water-balance methods are generally inapplicable in semiarid regions. Examples from Africa (Senegal, Niger, Nigeria, Sudan as well as Cyprus) show that direct recharge rates may vary from zero to around 40% of mean rainfall, dependent primarily on the soil depth and the lithology. Spatial variability presents a real problem in any recharge investigation but results from Senegal show that unsaturated zone profiles may be extrapolated using the chemistry of shallow groundwater. Unsaturated-zone studies show that there are limiting conditions to direct recharge through soil, but that present day replenishment of aquifers takes place via wadis and channels. In the Butana area of central Sudan the regional groundwater was also recharged during a mid-Holocene wet phase and is now in decline. The only current recharge sources, which can be recognised distinctly using stable isotopes, are Nile baseflow and ephemeral wadi floods. (author)

  18. Groundwater recharge and flow on Montserrat, West Indies: Insights from groundwater dating

    OpenAIRE

    Hemmings, Brioch; Gooddy, Daren; Whitaker, Fiona; George Darling, W.; Jasim, Alia; Gottsmann, Joachim

    2015-01-01

    Study region Montserrat, Lesser Antilles, Caribbean. Study focus Analysis of δ2H and δ18O isotopes, and chlorofluorocarbon (CFC) anthropogenic tracers in Montserrat groundwater provides insights into the age and provenance of the spring waters. New hydrological insights δ2H and δ18O analysis indicates uniform recharge elevations for groundwaters on Montserrat. CFC-11 and CFC-12 analysis reveals age differences between isotopically similar, high elevation springs and low eleva...

  19. Assessment of check-dam groundwater recharge with water-balance calculations

    Science.gov (United States)

    Djuma, Hakan; Bruggeman, Adriana; Camera, Corrado; Eliades, Marinos

    2017-04-01

    Studies on the enhancement of groundwater recharge by check-dams in arid and semi-arid environments mainly focus on deriving water infiltration rates from the check-dam ponding areas. This is usually achieved by applying simple water balance models, more advanced models (e.g., two dimensional groundwater models) and field tests (e.g., infiltrometer test or soil pit tests). Recharge behind the check-dam can be affected by the built-up of sediment as a result of erosion in the upstream watershed area. This natural process can increase the uncertainty in the estimates of the recharged water volume, especially for water balance calculations. Few water balance field studies of individual check-dams have been presented in the literature and none of them presented associated uncertainties of their estimates. The objectives of this study are i) to assess the effect of a check-dam on groundwater recharge from an ephemeral river; and ii) to assess annual sedimentation at the check-dam during a 4-year period. The study was conducted on a check-dam in the semi-arid island of Cyprus. Field campaigns were carried out to measure water flow, water depth and check-dam topography in order to establish check-dam water height, volume, evaporation, outflow and recharge relations. Topographic surveys were repeated at the end of consecutive hydrological years to estimate the sediment built up in the reservoir area of the check dam. Also, sediment samples were collected from the check-dam reservoir area for bulk-density analyses. To quantify the groundwater recharge, a water balance model was applied at two locations: at the check-dam and corresponding reservoir area, and at a 4-km stretch of the river bed without check-dam. Results showed that a check-dam with a storage capacity of 25,000 m3 was able to recharge to the aquifer, in four years, a total of 12 million m3 out of the 42 million m3 of measured (or modelled) streamflow. Recharge from the analyzed 4-km long river section without

  20. Isotopic and hydrochemical evidence of groundwater recharge in the Hopq Desert, NW China

    International Nuclear Information System (INIS)

    Jian Ge; Tao Wang; Yafei Chen; Jiansheng Chen; Hohai University, Nanjing, Jiangsu Province; Lu Ge; Chao Wang

    2016-01-01

    Artesian wells and lakes are found in the hinterland of the Hopq Desert, China. Analysis of soil profiles has revealed that the local vadose zone is always in a state of water deficit because of strong evaporation, and precipitation cannot infiltrate into the groundwater. This research indicated that soil water and surface water are recharged by groundwater and that the groundwater is recharged via an external source. Analyses of the stable isotopes in precipitation and of the water budget suggested that surface water in the Qiangtang Basin on the Tibetan Plateau might correspond to the groundwater in the Hopq Desert. (author)

  1. Applying Environmental Isotope Theory to Groundwater Recharge in the Jiaozuo Mining Area, China

    Directory of Open Access Journals (Sweden)

    Pinghua Huang

    2017-01-01

    Full Text Available This study establishes the surface water evaporation line in theory and numerically simulates the δD and δ18O value distribution interval of the recharge source of deep groundwater in the Jiaozuo mining area. The recharge elevation is calculated based on hydrogen and oxygen isotope tracer theory. Theoretical calculation and experimental data indicate that the surface water evaporation line in the study area in theory is almost the same as the measured surface data-fitting line. A significant linear relationship is identified between δ18O and the elevation of spring outcrop. The topography increases per 100 m, and the δ18O value reduces by 0.23‰ on average. The δ18O value is converted into formula to calculate the groundwater recharge elevation, which is approximately from 400 to 800 m. The measured tritium values of karst groundwater are greater than 3 TU. The second factor score is a fraction distribution in shallow groundwater and negative fraction distribution in spring and deep groundwater, which indicates that the Northern Taihang Mountain is the main recharge area, where carbonate-exposed areas exist. The research conclusion holds a certain value for the flood evaluation of local coal mines.

  2. Groundwater Diffuse Recharge and its Response to Climate Changes in Semi-Arid Northwestern China

    Directory of Open Access Journals (Sweden)

    Lin Deng

    2015-01-01

    Full Text Available Understanding the processes and rates of groundwater recharge in arid and semi-arid areas is crucial for utilizing and managing groundwater resources sustainably. We obtained three chloride profiles of the unsaturated-zone in the desert/loess transition zone of northwestern China and reconstructed the groundwater recharge variations over the last 11, 21, and 37 years, respectively, using the generalized chloride mass balance (GCMB method. The average recharge rates were 43.7, 43.5, and 45.1 mm yr-1, respectively, which are similar to those evaluated by the chloride mass balance (CMB or GCMB methods in other semi-arid regions. The results indicate that the annual recharge rates were not in complete linear proportion to the corresponding annual precipitations, although both exhibited descending tendencies on the whole. Comparisons between the daily precipitation aggregate at different intensity and recharge rates reveal that the occurrence of relatively heavy daily precipitation per year may contribute to such nonlinearity between annual precipitation and recharge. The possible influences of vegetation cover alterations following precipitation change cannot be excluded as well. The approximately negative correlation between the average annual recharge and temperature suggests that changes in temperature have had significant influences on recharge.

  3. Simulation of the impact of managed aquifer recharge on the groundwater system in Hanoi, Vietnam

    Science.gov (United States)

    Glass, Jana; Via Rico, Daniela A.; Stefan, Catalin; Nga, Tran Thi Viet

    2018-05-01

    A transient numerical groundwater flow model using MODFLOW-NWT was set up and calibrated for Hanoi city, Vietnam, to understand the local groundwater flow system and to suggest solutions for sustainable water resource management. Urban development in Hanoi has caused a severe decline of groundwater levels. The present study evaluates the actual situation and investigates the suitability of managed aquifer recharge (MAR) to stop further depletion of groundwater resources. The results suggest that groundwater is being overexploited, as vast cones of depression exist in parts of the study area. Suitable locations to implement two MAR techniques—riverbank filtration and injection wells—were identified using multi-criteria decision analysis based on geographic information system (GIS). Three predictive scenarios were simulated. The relocation of pumping wells towards the Red River to induce riverbank filtration (first scenario) demonstrates that groundwater levels can be increased, especially in the depression cones. Groundwater levels can also be improved locally by the infiltration of surplus water into the upper aquifer (Holocene) via injection wells during the rainy season (second scenario), but this is not effective to raise the water table in the depression cones. Compared to the first scenario, the combination of riverbank filtration and injection wells (third scenario) shows a slightly raised overall water table. Groundwater flow modeling suggests that local overexploitation can be stopped by a smart relocation of wells from the main depression cones and the expansion of riverbank filtration. This could also avoid further land subsidence while the city's water demand is met.

  4. Climatic controls on diffuse groundwater recharge across Australia

    Directory of Open Access Journals (Sweden)

    O. V. Barron

    2012-12-01

    Full Text Available Reviews of field studies of groundwater recharge have attempted to investigate how climate characteristics control recharge, but due to a lack of data have not been able to draw any strong conclusions beyond that rainfall is the major determinant. This study has used numerical modelling for a range of Köppen-Geiger climate types (tropical, arid and temperate to investigate the effect of climate variables on recharge for different soil and vegetation types. For the majority of climate types, the correlation between the modelled recharge and total annual rainfall is weaker than the correlation between recharge and the annual rainfall parameters reflecting rainfall intensity. Under similar soil and vegetation conditions for the same annual rainfall, annual recharge in regions with winter-dominated rainfall is greater than in regions with summer-dominated rainfall. The importance of climate parameters other than rainfall in recharge estimation is highest in the tropical climate type. Mean annual values of solar radiation and vapour pressure deficit show a greater importance in recharge estimation than mean annual values of the daily mean temperature. Climate parameters have the lowest relative importance in recharge estimation in the arid climate type (with cold winters and the temperate climate type. For 75% of all soil, vegetation and climate types investigated, recharge elasticity varies between 2 and 4 indicating a 20% to 40% change in recharge for a 10% change in annual rainfall. Understanding how climate controls recharge under the observed historical climate allows more informed choices of analogue sites if they are to be used for climate change impact assessments.

  5. Recharge and discharge calculations to characterize the groundwater hydrologic balance

    International Nuclear Information System (INIS)

    Liddle, R.G.

    1998-01-01

    Several methods are presented to quantify the ground water component of the hydrologic balance; including (1) hydrograph separation techniques, (2) water budget calculations, (3) spoil discharge techniques, and (4) underground mine inflow studies. Stream hydrograph analysis was used to calculate natural groundwater recharge and discharge rates. Yearly continuous discharge hydrographs were obtained for 16 watersheds in the Cumberland Plateau area of Tennessee. Baseflow was separated from storm runoff using computerized hydrograph analysis techniques developed by the USGS. The programs RECESS, RORA, and PART were used to develop master recession curves, calculate ground water recharge, and ground water discharge respectively. Station records ranged from 1 year of data to 60 years of data with areas of 0.67 to 402 square miles. Calculated recharge ranged from 7 to 28 inches of precipitation while ground water discharge ranged from 6 to 25 inches. Baseflow ranged from 36 to 69% of total flow. For sites with more than 4 years of data the median recharge was 20 inches/year and the 95% confidence interval for the median was 16.4 to 23.8 inches of recharge. Water budget calculations were also developed independently by a mining company in southern Tennessee. Results showed about 19 inches of recharge is available on a yearly basis. A third method used spoil water discharge measurements to calculate average recharge rate to the mine. Results showed 21.5 inches of recharge for this relatively flat area strip mine. In a further analysis it was shown that premining soil recharge rates of 19 inches consisted of about 17 inches of interflow and 2 inches of deep aquifer recharge while postmining recharge to the spoils had almost no interflow component. OSM also evaluated underground mine inflow data from northeast Tennessee and southeast Kentucky. This empirical data showed from 0.38 to 1.26 gallons per minute discharge per unit acreage of underground workings. This is the

  6. Ground-water recharge from small intermittent streams in the western Mojave Desert, California: Chapter G in Ground-water recharge in the arid and semiarid southwestern United States (Professional Paper 1703)

    Science.gov (United States)

    Izbicki, John A.; Johnson, Russell U.; Kulongoski, Justin T.; Predmore, Steven; Stonestrom, David A.; Constantz, Jim; Ferré, Ty P.A.; Leake, Stanley A.

    2007-01-01

    Population growth has impacted ground-water resources in the western Mojave Desert, where declining water levels suggest that recharge rates have not kept pace with withdrawals. Recharge from the Mojave River, the largest hydrographic feature in the study area, is relatively well characterized. In contrast, recharge from numerous smaller streams that convey runoff from the bounding mountains is poorly characterized. The current study examined four representative streams to assess recharge from these intermittent sources. Hydraulic, thermal, geomorphic, chemical, and isotopic data were used to study recharge processes, from streamflow generation and infiltration to percolation through the unsaturated zone. Ground-water movement away from recharge areas was also assessed.Infiltration in amounts sufficient to have a measurable effect on subsurface temperature profiles did not occur in every year in instrumented study reaches. In addition to streamflow availability, results showed the importance of sediment texture in controlling infiltration and eventual recharge. Infiltration amounts of about 0.7 meters per year were an approximate threshold for the occurrence of ground-water recharge. Estimated travel times through the thick unsaturated zones underlying channels reached several hundred years. Recharging fluxes were influenced by stratigraphic complexity and depositional dynamics. Because of channel meandering, not all water that penetrates beneath the root zone can be assumed to become recharge on active alluvial fans.Away from study washes, elevated chloride concentrations and highly negative water potentials beneath the root zone indicated negligible recharge from direct infiltration of precipitation under current climatic conditions. In upstream portions of washes, generally low subsurface chloride concentrations and near-zero water potentials indicated downward movement of water toward the water table, driven primarily by gravity. Recharging conditions did not

  7. GEOCHEMICAL AND ISOTOPIC CONSTRAINTS ON GROUND-WATER FLOW DIRECTIONS, MIXING AND RECHARGE AT YUCCA MOUNTAIN, NEVADA

    International Nuclear Information System (INIS)

    A. Meijer; E. Kwicklis

    2000-01-01

    This analysis is governed by the Office of Civilian Radioactive Waste Management (OCRWM) Analysis and Modeling Report Development Plan entitled ''Geochemical and Isotopic Constraints on Groundwater Flow Directions, Mixing and Recharge at Yucca Mountain'' (CRWMS M and O 1999a). As stated in this Development Plan, the purpose of the work is to provide an analysis of groundwater recharge rates, flow directions and velocities, and mixing proportions of water from different source areas based on groundwater geochemical and isotopic data. The analysis of hydrochemical and isotopic data is intended to provide a basis for evaluating the hydrologic system at Yucca Mountain independently of analyses based purely on hydraulic arguments. Where more than one conceptual model for flow is possible, based on existing hydraulic data, hydrochemical and isotopic data may be useful in eliminating some of these conceptual models. This report documents the use of geochemical and isotopic data to constrain rates and directions of groundwater flow near Yucca Mountain and the timing and magnitude of recharge in the Yucca Mountain vicinity. The geochemical and isotopic data are also examined with regard to the possible dilution of groundwater recharge from Yucca Mountain by mixing with groundwater downgradient from the potential repository site. Specifically, the primary tasks of this report, as listed in the AMR Development Plan (CRWMS M and O 1999a), consist of the following: (1) Compare geochemical and isotopic data for perched and pore water in the unsaturated zone with similar data from the saturated zone to determine if local recharge is present in the regional groundwater system; (2) Determine the timing of the recharge from stable isotopes such as deuterium ( 2 H) and oxygen-18 ( 18 O), which are known to vary over time as a function of climate, and from radioisotopes such as carbon-14 ( 14 C) and chlorine-36 ( 36 Cl); (3) Determine the magnitude of recharge from relatively

  8. Analysis of confidence in continental-scale groundwater recharge estimates for Africa using a distributed water balance model

    Science.gov (United States)

    Mackay, Jonathan; Mansour, Majdi; Bonsor, Helen; Pachocka, Magdalena; Wang, Lei; MacDonald, Alan; Macdonald, David; Bloomfield, John

    2014-05-01

    There is a growing need for improved access to reliable water in Africa as population and food production increases. Currently approximately 300 million people do not have access to a secure source of safe drinking water. To meet these current and future demands, groundwater will need to be increasingly abstracted; groundwater is more reliable than surface water sources due to its relatively long response time to meteorological stresses and therefore is likely to be a more secure water resource in a more variable climate. Recent studies also quantified the volumes of groundwater potentially available which suggest that, if exploited, groundwater could help to meet the demand for fresh water. However, there is still considerable uncertainty as to how these resources may respond in the future due to changes in groundwater recharge and abstraction. Understanding and quantifying groundwater recharge is vital as it forms a primary indicator of the sustainability of underlying groundwater resources. Computational hydrological models provide a means to do this, but the complexity of recharge processes in Africa mean that these simulations are often highly uncertain. This study aims to evaluate our confidence in simulating groundwater recharge over Africa based on a sensitivity analysis using a distributed hydrological model developed by the British Geological Survey, ZOODRM. The model includes land surface, canopy, river, soil and groundwater components. Each component is able to exchange water and as such, forms a distributed water balance of Africa. The components have been parameterised using available spatial datasets of African vegetation, land-use, soil and hydrogeology while the remaining parameters have been estimated by calibrating the model to available river flow data. Continental-scale gridded precipitation and potential evapotranspiration datasets, based on remotely sensed and ground observations, have been used to force the model. Following calibration, the

  9. Numerical simulation of groundwater artificial recharge in a semiarid-climate basin of northwest Mexico, case study the Guadalupe Valley Aquifer, Baja California

    Science.gov (United States)

    Campos-Gaytan, J. R.; Herrera-Oliva, C. S.

    2013-05-01

    In this study was analyzed through a regional groundwater flow model the effects on groundwater levels caused by the application of different future groundwater management scenarios (2007-2025) at the Guadalupe Valley, in Baja California, Mexico. Among these studied alternatives are those scenarios designed in order to evaluate the possible effects generated for the groundwater artificial recharge in order to satisfy a future water demand with an extraction volume considered as sustainable. The State of Baja California has been subject to an increment of the agricultural, urban and industrials activities, implicating a growing water-demand. However, the State is characterized by its semiarid-climate with low surface water availability; therefore, has resulted in an extensive use of groundwater in local aquifer. Water level measurements indicate there has been a decline in water levels in the Guadalupe Valley for the past 30 years. The Guadalupe Valley aquifer represents one the major sources of water supply in Ensenada region. It supplies about 25% of the water distributed by the public water supplier at the city of Ensenada and in addition constitutes the main water resource for the local wine industries. Artificially recharging the groundwater system is one water resource option available to the study zone, in response to increasing water demand. The existing water supply system for the Guadalupe Valley and the city of Ensenada is limited since water use demand periods in 5 to 10 years or less will require the construction of additional facilities. To prepare for this short-term demand, one option available to water managers is to bring up to approximately 3.0 Mm3/year of treated water of the city of Ensenada into the valley during the low-demand winter months, artificially recharge the groundwater system, and withdraw the water to meet the summer demands. A 2- Dimensional groundwater flow was used to evaluate the effects of the groundwater artificial recharge

  10. The Impact of a Check Dam on Groundwater Recharge and Sedimentation in an Ephemeral Stream

    Directory of Open Access Journals (Sweden)

    Hakan Djuma

    2017-10-01

    Full Text Available Despite the widespread presence of groundwater recharge check dams, there are few studies that quantify their functionality. The objectives of this study are (i to assess groundwater recharge in an ephemeral river with and without a check dam and (ii to assess sediment build-up in the check-dam reservoir. Field campaigns were carried out to measure water flow, water depth, and check-dam topography to establish water volume, evaporation, outflow, and recharge relations, as well as sediment build-up. To quantify the groundwater recharge, a water-balance approach was applied at two locations: at the check dam reservoir area and at an 11 km long natural stretch of the river upstream. Prediction intervals were computed to assess the uncertainties of the results. During the four years of operation, the check dam (storage capacity of 25,000 m3 recharged the aquifer with an average of 3.1 million m3 of the 10.4 million m3 year−1 of streamflow (30%. The lower and upper uncertainty limits of the check dam recharge were 0.1 and 9.6 million m3 year−1, respectively. Recharge from the upstream stretch was 1.5 million m3 year−1. These results indicate that check dams are valuable structures for increasing groundwater resources in semi-arid regions.

  11. Numerical groundwater-flow modeling to evaluate potential effects of pumping and recharge: implications for sustainable groundwater management in the Mahanadi delta region, India

    Science.gov (United States)

    Sahoo, Sasmita; Jha, Madan K.

    2017-12-01

    Process-based groundwater models are useful to understand complex aquifer systems and make predictions about their response to hydrological changes. A conceptual model for evaluating responses to environmental changes is presented, considering the hydrogeologic framework, flow processes, aquifer hydraulic properties, boundary conditions, and sources and sinks of the groundwater system. Based on this conceptual model, a quasi-three-dimensional transient groundwater flow model was designed using MODFLOW to simulate the groundwater system of Mahanadi River delta, eastern India. The model was constructed in the context of an upper unconfined aquifer and lower confined aquifer, separated by an aquitard. Hydraulic heads of 13 shallow wells and 11 deep wells were used to calibrate transient groundwater conditions during 1997-2006, followed by validation (2007-2011). The aquifer and aquitard hydraulic properties were obtained by pumping tests and were calibrated along with the rainfall recharge. The statistical and graphical performance indicators suggested a reasonably good simulation of groundwater flow over the study area. Sensitivity analysis revealed that groundwater level is most sensitive to the hydraulic conductivities of both the aquifers, followed by vertical hydraulic conductivity of the confining layer. The calibrated model was then employed to explore groundwater-flow dynamics in response to changes in pumping and recharge conditions. The simulation results indicate that pumping has a substantial effect on the confined aquifer flow regime as compared to the unconfined aquifer. The results and insights from this study have important implications for other regional groundwater modeling studies, especially in multi-layered aquifer systems.

  12. Effect to groundwater recharge caused by land use change, comparative filed observation in forest and grassland watersheds, Southwestern Japan

    Science.gov (United States)

    Kudo, K.; Shimada, J.; Tanaka, N.

    2011-12-01

    City of Kumamoto and their surrounding area are totally supported by the local groundwater as their tap water source, which is quite unique as comparing to the other large cities in Japan because Japanese large cities are mostly supplied by the surface water which is relatively easy to access for their tap water. Because of this, prefecture government of the Kumamoto City has much concern about the sustainable use of groundwater resources for their future generations. In Japan, for the sustainable use of groundwater resources, the forestation in the groundwater recharge area believed to increase the groundwater recharge to the local groundwater aquifer. It is true that the forestation surely works to reduce the direct runoff rate during the flooding period and also works to maintain a bit higher base flow rate during the low flow period than without forestation. However, the effect to the groundwater recharge rate by the forestation is not well understood because of the increase of evapo-transpiration by the tree itself. In order to understand the change of the groundwater recharge rate by the forestation, a paired catchments field observation has been conducted in two adjacent forest (0.088km2) and grassland (0.14km2) watersheds at the western foot of Mt. Aso known as recharge area of major local aquifer of Kumamoto region. The study sites are located at 32°53'N, 130°57'E with elevation ranging from 500 to 800m. The forest watershed consists mainly of around 30 year aged Japanese cypress plantations surrounded by Japanese cedar and mixture forest. The grassland watershed consists mainly of pasture and Japanese silver grass. Both catchments develop on the mountain foot slope consists of the Aso-2 pyroclastic sediments. As for the hydrometric observation system for each catchments, parshall flume runoff weir for the river discharge, meteoric tower for the evapo-transpiration monitoring purpose, and precipitation gage are installed to calculate groundwater recharge

  13. Virus removal during groundwater recharge: effects of infiltration rate on adsorption of poliovirus to soil.

    OpenAIRE

    Vaughn, J M; Landry, E F; Beckwith, C A; Thomas, M Z

    1981-01-01

    Studies were conducted to determine the influence of infiltration rate on poliovirus removal during groundwater recharge with tertiary-treated wastewater effluents. Experiments were conducted at a uniquely designed, field-situated test recharge basin facility through which some 62,000 m3 of sewage had been previously applied. Recharge at high infiltration rates (75 to 100 cm/h) resulted in the movement of considerable numbers of seeded poliovirus to the groundwater. Moderately reduced infiltr...

  14. Using stable isotopes to characterize groundwater recharge sources in the volcanic island of Madeira, Portugal

    Science.gov (United States)

    Prada, Susana; Cruz, J. Virgílio; Figueira, Celso

    2016-05-01

    The hydrogeology of volcanic islands remains poorly understood, despite the fact that populations that live on them rely on groundwater as a primary water source. This situation is exacerbated by their complex structure, geological heterogeneity, and sometimes active volcanic processes that hamper easy analysis of their hydrogeological dynamics. Stable isotope analysis is a powerful tool that has been used to assess groundwater dynamics in complex terrains. In this work, stable isotopes are used to better understand the hydrogeology of Madeira Island and provide a case-study that can serve as a basis for groundwater studies in other similar settings. The stable isotopic composition (δ18O and δ2H) of rain at the main recharge areas of the island is determined, as well as the sources and altitudes of recharge of several springs, groundwater in tunnels and wells. The water in tunnels was found to be recharged almost exclusively by rain in the deforested high plateaus, whilst several springs associated with shallow perched aquifers are recharged from rain and cloud water interception by the vegetated slopes. Nevertheless some springs thought to be sourced from deep perched aquifers, recharge in the central plateaus, and their isotopic composition is similar to the water in the tunnels. Recharge occurs primarily during autumn and winter, as evidenced by the springs and tunnels Water Lines (WL). The groundwater in wells appears to originate from runoff from rain that falls along the slopes that infiltrates near the streams' mouths, where the wells are located. This is evident by the evaporation line along which the wells plot. Irrigation water is also a possible source of recharge. The data is compatible with the hydrogeological conceptual model of Madeira. This work also shows the importance of cloud water interception as a net contributor to groundwater recharge, at least in the perched aquifers that feed numerous springs. As the amount of rainfall is expected to

  15. Estimates of ground-water recharge rates for two small basins in central Nevada

    Science.gov (United States)

    Lichty, R.W.; McKinley, P.W.

    1995-01-01

    Estimates of ground-water recharge rates developed from hydrologic modeling studies are presented for 3-Springs and East Stewart basins. two small basins (analog sites) located in central Nevada. The analog-site studies were conducted to aid in the estimation of recharge to the paleohydrologic regime associated with ground water in the vicinity of Yucca Mountain under wetter climatic conditions. The two analog sites are located to the north and at higher elevations than Yucca Mountain, and the prevailing (current) climatic conditions at these sites is thought to be representative of the possible range of paleoclimatic conditions in the general area of Yucca Mountain during the Quaternary. Two independent modeling approaches were conducted at each of the analog sites using observed hydrologic data on precipitation, temperature, solar radiation stream discharge, and chloride-ion water chemistry for a 6-year study period (October 1986 through September 1992). Both models quantify the hydrologic water-balance equation and yield estimates of ground-water recharge, given appropriate input data. The first model uses a traditional approach to quantify watershed hydrology through a precipitation-runoff modeling system that accounts for the spatial variability of hydrologic inputs, processes, and responses (outputs) using a dailycomputational time step. The second model is based on the conservative nature of the dissolved chloride ion in selected hydrologic environments, and its use as a natural tracer allows the computation of acoupled, water and chloride-ion, mass-balance system of equations to estimate available water (sum ofsurface runoff and groundwater recharge). Results of the modeling approaches support the conclusion that reasonable estimates of average-annual recharge to ground water range from about 1 to 3 centimeters per year for 3-Springs basin (the drier site), and from about 30 to 32 centimeters per year for East Stewart basin (the wetter site). The most

  16. Hydrogeological evaluation of an over-exploited aquifer in Dhaka, Bangladesh towards the implementation of groundwater artificial recharge

    Science.gov (United States)

    Azizur Rahman, M.; Rusteberg, Bernd; Sauter, Martin

    2010-05-01

    The population of Dhaka City is presently about 12 million and according to present trends in population growth, that number will most likely increase to 17.2 million by the year 2025. A serious water crisis is expected due to the extremely limited quality and quantity of water resources in the region. Previous studies have shown that the current trend in groundwater resource development is non-sustainable due to over-exploitation of the regional aquifer system, resulting in rapidly decreasing groundwater levels of about 2 to 3 meters per year. Today, annual groundwater extraction clearly exceeds natural groundwater recharge. New water management strategies are needed to guarantee future generations of Dhaka City a secured and sustained water supply as well as sustainable development of the city. The implementation of groundwater artificial recharge (AR) is one potential measure. As the first step towards a new water management strategy for Dhaka City, the authors report on the hydrogeological conditions of the greater Dhaka region and from this are able to present the location of potential recharge sites and identify appropriate recharge technologies for AR implementation. The aquifers of greater Dhaka can be grouped in three major categories: Holocene Deposit, Pleistocene Deposit and Plio-Pleistocene Deposit. The aquifers are generally thick and multilayered with relatively high transmissivity and storage coefficients. AR is considered feasible due to the fact these aquifers are alluvium deposit aquifers which characteristically have moderate to high hydraulic conductivity. Low costs for recovery of recharged water and large recharge volume capacity are generally associated with aquifers of unconsolidated sediments. Spatial analysis of the region has shown that Karaniganj, Kotoali, Savar, Dhamrai, Singair upazila, which are situated in greater Dhaka region and close to Dhaka City, could serve as recharge sites to the subsurface by pond infiltration technique. A

  17. Ecotoxicity assessment of artificial groundwater recharge with reclaimed water: a pilot-scale study.

    Science.gov (United States)

    Zhang, Xue; Zhao, Xuan

    2013-11-01

    A demonstration of artificial groundwater recharge with tertiary effluent was evaluated using a set of bioassays (acute toxicity to Daphnia, genotoxicity, estrogenic and antiestrogenic toxicity). Around 95 % genotoxicity and 53 % antiestrogenicity were removed from the feed water by ozonation, whereas significant reduction of acute toxicity to Daphnia magna was achieved during a 3 days vadose soil treatment. The toxicity was further removed to the same level as the local groundwater during a 20 days aquifer soil treatment. The pilot study has shown that ozonation and soil treatments can improve the quality of municipal wastewater treatment plant effluents for possible groundwater recharge purposes.

  18. Computation of groundwater resources and recharge in Chithar River Basin, South India.

    Science.gov (United States)

    Subramani, T; Babu, Savithri; Elango, L

    2013-01-01

    Groundwater recharge and available groundwater resources in Chithar River basin, Tamil Nadu, India spread over an area of 1,722 km(2) have been estimated by considering various hydrological, geological, and hydrogeological parameters, such as rainfall infiltration, drainage, geomorphic units, land use, rock types, depth of weathered and fractured zones, nature of soil, water level fluctuation, saturated thickness of aquifer, and groundwater abstraction. The digital ground elevation models indicate that the regional slope of the basin is towards east. The Proterozoic (Post-Archaean) basement of the study area consists of quartzite, calc-granulite, crystalline limestone, charnockite, and biotite gneiss with or without garnet. Three major soil types were identified namely, black cotton, deep red, and red sandy soils. The rainfall intensity gradually decreases from west to east. Groundwater occurs under water table conditions in the weathered zone and fluctuates between 0 and 25 m. The water table gains maximum during January after northeast monsoon and attains low during October. Groundwater abstraction for domestic/stock and irrigational needs in Chithar River basin has been estimated as 148.84 MCM (million m(3)). Groundwater recharge due to monsoon rainfall infiltration has been estimated as 170.05 MCM based on the water level rise during monsoon period. It is also estimated as 173.9 MCM using rainfall infiltration factor. An amount of 53.8 MCM of water is contributed to groundwater from surface water bodies. Recharge of groundwater due to return flow from irrigation has been computed as 147.6 MCM. The static groundwater reserve in Chithar River basin is estimated as 466.66 MCM and the dynamic reserve is about 187.7 MCM. In the present scenario, the aquifer is under safe condition for extraction of groundwater for domestic and irrigation purposes. If the existing water bodies are maintained properly, the extraction rate can be increased in future about 10% to 15%.

  19. The Definition of Groundwater Recharge Area Using GIS Approach -A Case Study of Choshuihsi Alluvial Fan, Taiwan

    Science.gov (United States)

    Tsai, JuiPin; Chen, Yu Wen; Chang, Liang Cheng; Chiang, Chun Jung; Chen, Jui Er; Chen, You Cheng

    2013-04-01

    Groundwater recharge areas are regions with high permeability that accept surface water more readily than other regions. If the land use/cover were changed, it would affect the groundwater recharge. Also, if this area were polluted, the contamination easily infiltrates into the groundwater system. Therefore, the goal of this study is to delineate the recharge area of Choshuihsi Alluvial Fan. This study applies 6 recharge potential scale factors, including land use/land cover, soil, drainage density, annual average rainfall, hydraulic conductivity and aquifer thickness to estimate the infiltration ability and storage capacity of study area. The fundamental data of these factors were digitized using GIS (Geographic Information System) technology and their GIS maps were created. Then each of these maps was translated to a score map ranged from 1 to 100. Moreover, these score maps are integrated as a recharge potential map using arithmetic average, and this map shows recharge potential in 5 levels, such as very poor, poor, moderate, good and excellent. The result shows that majority of "good" and "excellent" areas is located at the top of the fan. This is because the land use of top-fan is agricultural and its surface soil type is gravel and coarse. The top-fan, which is close to mountain areas, has a higher average annual rainfall than other areas. Also, the aquifer thickness of top-fan is much thicker than other areas. The percentage of the areas ranged as "good" and above is 9.63% of total area, and most areas located at top-fan. As a result, we suggest that the top-fan of study area should be protected and more field surveys are required to accurately delineate the recharge area boundary.

  20. Assessing the recharge of a coastal aquifer using physical observations, tritium, groundwater chemistry and modelling.

    Science.gov (United States)

    Santos, Isaac R; Zhang, Chenming; Maher, Damien T; Atkins, Marnie L; Holland, Rodney; Morgenstern, Uwe; Li, Ling

    2017-02-15

    Assessing recharge is critical to understanding groundwater and preventing pollution. Here, we investigate recharge in an Australian coastal aquifer using a combination of physical, modelling and geochemical techniques. We assess whether recharge may occur through a pervasive layer of floodplain muds that was initially hypothesized to be impermeable. At least 59% of the precipitation volume could be accounted for in the shallow aquifer using the water table fluctuation method during four significant recharge events. Precipitation events rates were estimated in the area underneath the floodplain clay layer rather than in the sandy area. A steady-state chloride method implied recharge rates of at least 200mm/year (>14% of annual precipitation). Tritium dating revealed long term net vertical recharge rates ranging from 27 to 114mm/year (average 58mm/year) which were interpreted as minimum net long term recharge. Borehole experiments revealed more permeable conditions and heterogeneous infiltration rates when the floodplain soils were dry. Wet conditions apparently expand floodplain clays, closing macropores and cracks that act as conduits for groundwater recharge. Modelled groundwater flow paths were consistent with tritium dating and provided independent evidence that the clay layer does not prevent local recharge. Overall, all lines of evidence demonstrated that the coastal floodplain muds do not prevent the infiltration of rainwater into the underlying sand aquifer, and that local recharge across the muds was widespread. Therefore, assuming fine-grained floodplain soils prevent recharge and protect underlying aquifers from pollution may not be reasonable. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Groundwater recharge patterns in the Yobe river Fadama: evidence from hydrochemistry

    International Nuclear Information System (INIS)

    Agbo, J.U.; Alkali, S.C.; Nwaiwu, M. O.

    1998-01-01

    Twenty Groundwater monitor Piezometers installed linearly away from the channel of River Yobe, on opposing banks were monitored across the rainy and dry seasons of 1993. Results indicate that water levels rose rapidly in July attaining levels above ground surface in September, and by October the water level was at the decline. These coincided with the advance and the retreat of the Yobe River flood, suggestive of the Yobe River having a significant influence on the recharge to the alluvial aquifers of the Fadama. Results of chemical analyses of water samples collected from the piezometers, river water, and flood water, suggest that groundwater of the shallow alluvial aquifers do not seem to have a common immediate source with the surface water sources of the Fadama. Hydrochemical concentration trend show concentration gradient towards the river channel, implying that the river might not be the source of the groundwater recharge to the Yobe River Fadama aquifers. Groundwater flow characteristics, also seem to support this view, since there is flow gradient towards the river for the greater part of the year except during peak flood when there are indications of flow (by way of higher potentiometric surface) away from the river. These and other evidences discussed in the paper suggest that the Fadama alluvial aquifer gets most of its recharge directly from rainfall infiltration in regions devoid of clay cover

  2. Numerical simulation of groundwater movement and managed aquifer recharge from Sand Hollow Reservoir, Hurricane Bench area, Washington County, Utah

    Science.gov (United States)

    Marston, Thomas M.; Heilweil, Victor M.

    2012-01-01

    The Hurricane Bench area of Washington County, Utah, is a 70 square-mile area extending south from the Virgin River and encompassing Sand Hollow basin. Sand Hollow Reservoir, located on Hurricane Bench, was completed in March 2002 and is operated primarily as a managed aquifer recharge project by the Washington County Water Conservancy District. The reservoir is situated on a thick sequence of the Navajo Sandstone and Kayenta Formation. Total recharge to the underlying Navajo aquifer from the reservoir was about 86,000 acre-feet from 2002 to 2009. Natural recharge as infiltration of precipitation was approximately 2,100 acre-feet per year for the same period. Discharge occurs as seepage to the Virgin River, municipal and irrigation well withdrawals, and seepage to drains at the base of reservoir dams. Within the Hurricane Bench area, unconfined groundwater-flow conditions generally exist throughout the Navajo Sandstone. Navajo Sandstone hydraulic-conductivity values from regional aquifer testing range from 0.8 to 32 feet per day. The large variability in hydraulic conductivity is attributed to bedrock fractures that trend north-northeast across the study area.A numerical groundwater-flow model was developed to simulate groundwater movement in the Hurricane Bench area and to simulate the movement of managed aquifer recharge from Sand Hollow Reservoir through the groundwater system. The model was calibrated to combined steady- and transient-state conditions. The steady-state portion of the simulation was developed and calibrated by using hydrologic data that represented average conditions for 1975. The transient-state portion of the simulation was developed and calibrated by using hydrologic data collected from 1976 to 2009. Areally, the model grid was 98 rows by 76 columns with a variable cell size ranging from about 1.5 to 25 acres. Smaller cells were used to represent the reservoir to accurately simulate the reservoir bathymetry and nearby monitoring wells; larger

  3. New non-linear model of groundwater recharge: Inclusion of memory, heterogeneity and visco-elasticity

    Directory of Open Access Journals (Sweden)

    Spannenberg Jescica

    2017-09-01

    Full Text Available Fractional differentiation has adequate use for investigating real world scenarios related to geological formations associated with elasticity, heterogeneity, viscoelasticity, and the memory effect. Since groundwater systems exist in these geological formations, modelling groundwater recharge as a real world scenario is a challenging task to do because existing recharge estimation methods are governed by linear equations which make use of constant field parameters. This is inadequate because in reality these parameters are a function of both space and time. This study therefore concentrates on modifying the recharge equation governing the EARTH model, by application of the Eton approach. Accordingly, this paper presents a modified equation which is non-linear, and accounts for parameters in a way that it is a function of both space and time. To be more specific, herein, recharge and drainage resistance which are parameters within the equation, became a function of both space and time. Additionally, the study entailed solving the non-linear equation using an iterative method as well as numerical solutions by means of the Crank-Nicolson scheme. The numerical solutions were used alongside the Riemann-Liouville, Caputo-Fabrizio, and Atangana-Baleanu derivatives, so that account was taken for elasticity, heterogeneity, viscoelasticity, and the memory effect. In essence, this paper presents a more adequate model for recharge estimation.

  4. Increasing the utility of regional water table maps: a new method for estimating groundwater recharge

    Science.gov (United States)

    Gilmore, T. E.; Zlotnik, V. A.; Johnson, M.

    2017-12-01

    Groundwater table elevations are one of the most fundamental measurements used to characterize unconfined aquifers, groundwater flow patterns, and aquifer sustainability over time. In this study, we developed an analytical model that relies on analysis of groundwater elevation contour (equipotential) shape, aquifer transmissivity, and streambed gradient between two parallel, perennial streams. Using two existing regional water table maps, created at different times using different methods, our analysis of groundwater elevation contours, transmissivity and streambed gradient produced groundwater recharge rates (42-218 mm yr-1) that were consistent with previous independent recharge estimates from different methods. The three regions we investigated overly the High Plains Aquifer in Nebraska and included some areas where groundwater is used for irrigation. The three regions ranged from 1,500 to 3,300 km2, with either Sand Hills surficial geology, or Sand Hills transitioning to loess. Based on our results, the approach may be used to increase the value of existing water table maps, and may be useful as a diagnostic tool to evaluate the quality of groundwater table maps, identify areas in need of detailed aquifer characterization and expansion of groundwater monitoring networks, and/or as a first approximation before investing in more complex approaches to groundwater recharge estimation.

  5. Spatially distributed groundwater recharge estimated using a water-budget model for the Island of Maui, Hawai`i, 1978–2007

    Science.gov (United States)

    Johnson, Adam G.; Engott, John A.; Bassiouni, Maoya; Rotzoll, Kolja

    2014-12-14

    Demand for freshwater on the Island of Maui is expected to grow. To evaluate the availability of fresh groundwater, estimates of groundwater recharge are needed. A water-budget model with a daily computation interval was developed and used to estimate the spatial distribution of recharge on Maui for average climate conditions (1978–2007 rainfall and 2010 land cover) and for drought conditions (1998–2002 rainfall and 2010 land cover). For average climate conditions, mean annual recharge for Maui is about 1,309 million gallons per day, or about 44 percent of precipitation (rainfall and fog interception). Recharge for average climate conditions is about 39 percent of total water inflow consisting of precipitation, irrigation, septic leachate, and seepage from reservoirs and cesspools. Most recharge occurs on the wet, windward slopes of Haleakalā and on the wet, uplands of West Maui Mountain. Dry, coastal areas generally have low recharge. In the dry isthmus, however, irrigated fields have greater recharge than nearby unirrigated areas. For drought conditions, mean annual recharge for Maui is about 1,010 million gallons per day, which is 23 percent less than recharge for average climate conditions. For individual aquifer-system areas used for groundwater management, recharge for drought conditions is about 8 to 51 percent less than recharge for average climate conditions. The spatial distribution of rainfall is the primary factor determining spatially distributed recharge estimates for most areas on Maui. In wet areas, recharge estimates are also sensitive to water-budget parameters that are related to runoff, fog interception, and forest-canopy evaporation. In dry areas, recharge estimates are most sensitive to irrigated crop areas and parameters related to evapotranspiration.

  6. Seismicity Induced by Groundwater Recharge at Mt. Hood, Oregon, and its Implications for Hydrogeologic Properties.

    Science.gov (United States)

    Saar, M. O.; Manga, M.

    2002-12-01

    Earthquakes induced by human-caused changes in fluid pressure have been documented for many years. Examples include seismicity induced by filling reservoirs and by fluid injection or extraction. Less well-documented are seismic events that potentially are triggered by natural variations in groundwater recharge rates (e.g., Wolf et al., BSSA, 1997; Jimenez and Garcia-Fernandez, JVGR, 2000; Audin et al., GRL, 2002). Large groundwater recharge rates can occur in Volcanic Arcs such as the Oregon Cascades where annual precipitation is > 2 m of which > 50 % infiltrates the ground mostly during snowmelt in spring. As a result, infiltration rates of > 1 m per year concentrated during a few months can occur. Near-surface porosities are about 5-10 %. Thus, groundwater levels may fluctuate annually by about 10-20 m resulting in seasonal pore fluid pressure variations of about 1-2 x 105 Pa. Such large-amplitude, narrow-duration fluid pressure signals may allow investigation of seismicity induced by pore fluid pressure diffusion without the influence of engineered systems such as reservoirs. This kind of in-situ study of natural systems over large representative elementary volumes may allow determination of hydrologic parameters at spatial and temporal scales that are relevant for regional hydrogeology. Furthermore, natural hydrologic triggering of earthquakes that persist for decades provides insight into the state of stress in the crust and suggest long-term near-critical failure conditions. Here, we approximate the temporal variations in groundwater recharge with discharge in runoff-dominated streams at high elevations that show a peak in discharge during snow melt. Seismicity is evaluated as time series of daily number of earthquakes and seismic moments. Both stream discharge and seismicity are compared at equivalent frequency bands by applying segmented least-squares polynomial fits to the data. We find statistically significant correlation between groundwater recharge and

  7. Groundwater-surface water interaction

    International Nuclear Information System (INIS)

    White, P.A.; Clausen, B.; Hunt, B.; Cameron, S.; Weir, J.J.

    2001-01-01

    This chapter discusses natural and modified interactions between groundwater and surface water. Theory on recharge to groundwater from rivers is introduced, and the relative importance of groundwater recharge from rivers is illustrated with an example from the Ngaruroro River, Hawke's Bay. Some of the techniques used to identify and measure recharge to groundwater from gravel-bed rivers will be outlined, with examples from the Ngaruroro River, where the recharge reach is relatively well defined, and from the Rakaia River, where it is poorly defined. Groundwater recharged from rivers can have characteristic chemical and isotopic signatures, as shown by Waimakariri River water in the Christchurch-West Melton groundwater system. The incorporation of groundwater-river interaction in a regional groundwater flow model is outlined for the Waimea Plains, and relationships between river scour and groundwater recharge are examined for the Waimakariri River. Springs are the result of natural discharge from groundwater systems and are important water sources. The interactions between groundwater systems, springs, and river flow for the Avon River in New Zealand will be outlined. The theory of depletion of stream flow by groundwater pumpage will be introduced with a case study from Canterbury, and salt-water intrusion into groundwater systems with examples from Nelson and Christchurch. The theory of artificial recharge to groundwater systems is introduced with a case study from Hawke's Bay. Wetlands are important to flora, and the relationship of the wetland environment to groundwater hydrology will be discussed, with an example from the South Taupo wetland. (author). 56 refs., 25 figs., 3 tabs

  8. Uncertainties in the simulation of groundwater recharge at different scales

    Directory of Open Access Journals (Sweden)

    H. Bogena

    2005-01-01

    Full Text Available Digital spatial data always imply some kind of uncertainty. The source of this uncertainty can be found in their compilation as well as the conceptual design that causes a more or less exact abstraction of the real world, depending on the scale under consideration. Within the framework of hydrological modelling, in which numerous data sets from diverse sources of uneven quality are combined, the various uncertainties are accumulated. In this study, the GROWA model is taken as an example to examine the effects of different types of uncertainties on the calculated groundwater recharge. Distributed input errors are determined for the parameters' slope and aspect using a Monte Carlo approach. Landcover classification uncertainties are analysed by using the conditional probabilities of a remote sensing classification procedure. The uncertainties of data ensembles at different scales and study areas are discussed. The present uncertainty analysis showed that the Gaussian error propagation method is a useful technique for analysing the influence of input data on the simulated groundwater recharge. The uncertainties involved in the land use classification procedure and the digital elevation model can be significant in some parts of the study area. However, for the specific model used in this study it was shown that the precipitation uncertainties have the greatest impact on the total groundwater recharge error.

  9. SWB Groundwater Recharge Analysis, Catalina Island, California: Assessing Spatial and Temporal Recharge Patterns Within a Mediterranean Climate Zone

    Science.gov (United States)

    Harlow, J.

    2017-12-01

    Groundwater recharge quantification is a key parameter for sustainable groundwater management. Many recharge quantification techniques have been devised, each with advantages and disadvantages. A free, GIS based recharge quantification tool - the Soil Water Balance (SWB) model - was developed by the USGS to produce fine-tuned recharge constraints in watersheds and illuminate spatial and temporal dynamics of recharge. The subject of this research is to examine SWB within a Mediterranean climate zone, focusing on the Catalina Island, California. This project relied on publicly available online resources with the exception the geospatial processing software, ArcGIS. Daily climate station precipitation and temperature data was obtained from the Desert Research Institute for the years 2008-2014. Precipitation interpolations were performed with ArcGIS using the Natural Neighbor method. The USGS-National Map Viewer (NMV) website provided a 30-meter DEM - to interpolate high and low temperature ASCII grids using the Temperature Lapse Rate (TLR) method, to construct a D-8 flow direction grid for downhill redirection of soil-moisture saturated runoff toward non-saturated cells, and for aesthetic map creation. NMV also provided a modified Anderson land cover classification raster. The US Department of Agriculture-National Resource Conservation Service (NRCS) Web Soil Survey website provided shapefiles of soil water capacity and hydrologic soil groups. The Hargreaves and Samani method was implemented to determine evapotranspiration rates. The resulting SWB output data, in the form of ASCII grids are easily added to ArcGIS for quick visualization and data analysis (Figure 1). Calculated average recharge for 2008-2014 was 3537 inches/year, or 0.0174 acre feet/year. Recharge was 10.2% of the islands gross precipitation. The spatial distribution of the most significant recharge is in hotspots which dominate the residential hills above Avalon, followed by grassy/unvegetated areas

  10. Recharge Net Metering to Incentivize Sustainable Groundwater Management

    Science.gov (United States)

    Fisher, A. T.; Coburn, C.; Kiparsky, M.; Lockwood, B. S.; Bannister, M.; Camara, K.; Lozano, S.

    2016-12-01

    Stormwater runoff has often been viewed as a nuisance rather than a resource, but with passage of the Sustainable Groundwater Management Act (2014), many basins in California are taking a fresh look at options to enhance groundwater supplies with excess winter flows. In some basins, stormwater can be used for managed aquifer recharge (MAR), routing surface water to enhance groundwater resources. As with many public infrastructure programs, financing for stormwater-MAR projects can be a challenge, and there is a need for incentives that will engage stakeholders and offset operation and maintenance costs. The Pajaro Valley Water Management Agency (PVWMA), in central costal California, recently launched California's first Recharge Net Metering (ReNeM) program. MAR projects that are part of the ReNeM program are intended to generate ≥100 ac-ft/yr of infiltration benefit during a normal water year. A team of university and Resource Conservation District partners will collaborate to identify and assess potential project sites, screening for hydrologic conditions, expected runoff, ease and cost of project construction, and ability to measure benefits to water supply and quality. The team will also collect data and samples to measure the performance of each operating project. Groundwater wells within the PVWMA's service area are metered, and agency customers pay an augmentation fee for each unit of groundwater pumped. ReNeM projects will earn rebates of augmentation fees based on the amount of water infiltrated, with rebates calculated using a formula that accounts for uncertainties in the fate of infiltrated water, and inefficiencies in recovery. The pilot ReNeM program seeks to contribute 1000 ac-ft/yr of infiltration benefit by the end of the initial five-year operating period. ReNeM offers incentives that are distinct from those derived from traditional groundwater banking, and thus offers the potential for an innovative addition to the portfolio of options for

  11. Identifying the role of human-induced land-use change while assessing drought effects on groundwater recharge

    Science.gov (United States)

    Verbeiren, Boud; Weerasinghe, Imeshi; Vanderhaegen, Sven; Canters, Frank; Uljee, Inge; Engelen, Guy; Jacquemin, Ingrid; Tychon, Bernard; Vangelis, Harris; Tsakiris, George; Batelaan, Okke; Huysmans, Marijke

    2015-04-01

    Drought is mainly regarded as a purely natural phenomenon, driven by the natural variation in precipitation or rather the lack of precipitation. Nowadays many river catchments are, however, altered by human activities having direct effects on the catchment landscape and hydrological response. In case of the occurrence of drought events in those catchments it becomes more complex to determine the effects of drought. To what extent is the hydrological response a direct result of the natural phenomenon and what is the role of the human factor? In this study we focus on the effects of droughts on groundwater recharge. Reliable estimation of groundwater recharge in space and time is of utmost importance for sustainable management of groundwater resources. Groundwater recharge forms the main source for replenishing aquifers. The main factors influencing groundwater recharge are the soil and topographic characteristics, land use and climate. While the first two influencing factors are relatively static, the latter two are (highly) dynamic. Differentiating between the contributions of each of these influencing factors to groundwater recharge is a challenging but important task. On the one hand, the occurrence of meteorological drought events is likely to cause direct, potentially deteriorating, effects on groundwater recharge. On the other hand, this is also the case for on-going land-use dynamics such as extensive urbanisation. The presented methodology aims at distinguishing in space and time between climate (drought-related) and land-use (human-induced) effects, enabling to assess the effects of drought on groundwater recharge. The physically-based water balance model WetSpass is used to calculate groundwater recharge in a distributed way (space and time) for the Dijle-Demer catchments in Belgium. The key issue is to determine land-use dynamics in a consistent way. A land-use timeseries is build based on four base maps. Via a change trajectory analysis the consistency

  12. A validation of the 3H/3He method for determining groundwater recharge

    Science.gov (United States)

    Solomon, D. K.; Schiff, S. L.; Poreda, R. J.; Clarke, W. B.

    1993-09-01

    Tritium and He isotopes have been measured at a site where groundwater flow is nearly vertical for a travel time of 100 years and where recharge rates are spatially variable. Because the mid-1960s 3H peak (arising from aboveground testing of thermonuclear devices) is well-defined, the vertical groundwater velocity is known with unusual accuracy at this site. Utilizing 3H and its stable daughter 3He to determine groundwater ages, we compute a recharge rate of 0.16 m/yr, which agrees to within about 5% of the value based on the depth of the 3H peak (measured both in 1986 and 1991) and two-dimensional modeling in an area of high recharge. Zero 3H/3He age occurs at a depth that is approximately equal to the average depth of the annual low water table, even though the capillary fringe extends to land surface during most of the year at the study site. In an area of low recharge (0.05 m/yr) where the 3H peak (and hence the vertical velocity) is also well-defined, the 3H/3He results could not be used to compute recharge because samples were not collected sufficiently far above the 3H peak; however, modeling indicates that the 3H/3He age gradient near the water table is an accurate measure of vertical velocities in the low-recharge area. Because 3H and 3He have different diffusion coefficients, and because the amount of mechanical mixing is different in the area of high recharge than in the low-recharge area, we have separated the dispersive effects of mechanical mixing from molecular diffusion. We estimate a longitudinal dispersivity of 0.07 m and effective diffusion coefficients for 3H (3HHO) and 3He of 2.4×10-5 and 1.3×10-4 m2/day, respectively. Although the 3H/3He age gradient is an excellent indicator of vertical groundwater velocities above the mid-1960s 3H peak, dispersive mixing and diffusive loss of 3He perturb the age gradient near and below the 3H peak.

  13. Evaluating groundwater recharge variations under climate change in an endorheic basin of the Andean plateau

    Science.gov (United States)

    Blin, N.; Hausner, M. B.; Suarez, F. I.

    2017-12-01

    In arid and semi-arid regions, where surface water and precipitations are scarce, groundwater is the main source of drinking water that sustains human and natural ecosystems. Therefore, it is very important to consider the potential impacts of climate change that threaten the availability of this resource. The purpose of this study is to investigate the variations caused by climate change on the recharge of the regional groundwater aquifer at the Huasco salt flat, located in the Chilean Andean plateau. The Huasco salt flat basin has ecosystems sustained by wetlands that depend on the groundwater levels of this aquifer. Due to this reason, the Chilean government has declared this zone as protected. Hence, the assurance of the future availability of the groundwater resource becomes extremely important. The sustainable management of this resource requires reasonable estimates of recharge and evapotranspiration, which are highly dependent on the characteristics and processes occurring in the vadose zone, i.e., topography, soil type and land use, and their temporal and spatial variations are significant in arid regions. With this aim, a three-dimensional groundwater model, implemented in SWAT-MODFLOW, was developed to couple the saturated system with the vadose zone. The model was calibrated and validated using historic data. General circulation models (GCMs) were used as scenarios inputs of recharge to the groundwater model. Future simulations were run by applying an offset to the historic air temperatures and to the precipitation. These offsets were determined using a delta hybrid approach based on the Coupled Model Intercomparison Project Phase 5 (CMIP5) multi-model ensemble archive. The obtained results were downscaled to the 0.125º latitude x 0.125º longitude grid cell containing the basin of the Huasco salt flat. The hybrid approach considered the 10th, 50th and 90th percentiles of the projected temperature and precipitation output as three scenarios of climate

  14. Geophysical characterization of the role of fault and fracture systems for recharging groundwater aquifers from surface water of Lake Nasser

    Directory of Open Access Journals (Sweden)

    Khamis Mansour

    2018-06-01

    Full Text Available The role of the fracture system is important for enhancing the recharge or discharge of fluids in the subsurface reservoir. The Lake Nasser is consider one of the largest artificial lakes all over the world and contains huge bulk of storage water. In this study, the influence of fracture zones on subsurface fluid flow in groundwater reservoirs is investigated using geophysical techniques including seismicity, geoelectric and gravity data. These data have been utilized for exploring structural structure in south west Lake Nasser, and subsurface discontinuities (joints or faults notwithstanding its related fracture systems. Seismicity investigation gave us the comprehension of the dynamic geological structure sets and proposing the main recharging paths for the Nubian aquifer from Lake Nasser surface water. Processing and modelling of aerogravity data show that the greater thickness of sedimentary cover (700 m is located eastward and northward while basement outcrops occur at Umm Shaghir and Al Asr areas. Sixty-nine vertical electrical soundings (VES’s were used to delineate the subsurface geoelectric layers along eight profiles that help to realize the subsurface geological structure behind the hydrogeological conditions of the studied area. Keywords: Fracture system, Seismicity, Groundwater reservoir, Gravity, VES

  15. Investigating local variation in groundwater recharge along a topographic gradient, Walnut Creek, Iowa, USA

    Science.gov (United States)

    Schilling, K.E.

    2009-01-01

    Groundwater recharge is an important component to hydrologic studies but is known to vary considerably across the landscape. The purpose of this study was to examine 4 years of water-level behavior in a transect of four water-table wells installed at Walnut Creek, Iowa, USA to evaluate how groundwater recharge varied along a topographic gradient. The amount of daily water-table rise (WTR) in the wells was summed at monthly and annual scales and estimates of specific yield (Sy) were used to convert the WTR to recharge. At the floodplain site, Sy was estimated from the ratio of WTR to total rainfall and in the uplands was based on the ratio of baseflow to WTR. In the floodplain, where the water table is shallow, recharge occurred throughout the year whenever precipitation occurred. In upland areas where the water table was deeper, WTR occurred in a stepped fashion and varied by season. Results indicated that the greatest amount of water-table rise over the 4-year period was observed in the floodplain (379 mm), followed by the upland (211 mm) and sideslopes (122 mm). Incorporating spatial variability in recharge in a watershed will improve groundwater resource evaluation and flow and transport modeling. ?? Springer-Verlag 2008.

  16. Identification of artificial groundwater recharging zone using a GIS-based fuzzy logic approach: a case study in a coal mine area of the Damodar Valley, India

    Science.gov (United States)

    Tiwari, Ashwani Kumar; Lavy, Muriel; Amanzio, Gianpiero; De Maio, Marina; Singh, Prasoon Kumar; Mahato, Mukesh Kumar

    2017-12-01

    The West Bokaro coalfield is a richest coal-mining belt in the Damodar Valley, India. The extensive mining of the area has resulted in disruption of the groundwater availability in terms of both quantity and quality. This has led to a drinking water crisis, especially during the pre-monsoon period in the West Bokaro coalfield area. The characterization of the hydrogeological system and the artificial recharging of the aquifers might help to better manage the problem of the groundwater-level depletion. For this purpose, seven important hydrogeological factors (water depth, slope, drainage, soil, infiltration, lithology, and landuse) have been considered to define the most suitable locations for artificial groundwater recharging in the mining area. Different thematic maps were prepared from existing maps and data sets, remote-sensing images, and field investigations for identification of the most suitable locations for artificial recharge. Thematic layers for these parameters were prepared, classified, weighted, and integrated into a geographic information system (GIS) environment by means of fuzzy logic. The results of the study indicate that about 29 and 31% of the area are very suitable and suitable for recharging purposes in the West Bokaro coalfield. However, the rest of the area is moderate to unsuitable for recharging due to the ongoing mining and related activities in the study area. The groundwater recharging map of the study area was validated with measured electrical conductivity (EC) values in the groundwater, and it indicated that validation can be accepted for the identification of groundwater recharging sites. These findings are providing useful information for the proper planning and sustainable management of the groundwater resources in the study area.

  17. Groundwater recharge estimates in the Athabasca and Cold Lake oil sands areas

    International Nuclear Information System (INIS)

    MacMillan, G.J.; Smith, A.D.

    2009-01-01

    Groundwater recharge estimates for the Cold Lake and Athabasca oil sands region were presented. New oil sands projects planned for the future will require approximately 150,000 m 3 per day of groundwater. Regulators and public agencies are now investigating the potential impacts of oil sands operations on both shallow groundwater and surface water in the region. Maximum yields from the aquifers are also being estimated. Measurements are currently being taken to determine transmissivity, hydraulic pressure, storage potential and leakage. Numerical models are currently used to determine saturated zone recharge estimates and water table fluctuations. Isotope tracers are also being used to determine where groundwater flow potential is vertical as well as to determine correction factors for hydrogeological and geochemical conditions at each site. Darcy's Law is used to determine heat flow in the groundwater aquifers. To date, the studies have demonstrated that drilling fluids have been recovered at groundwater sites. Wells are often installed near water supply and supply well networks. It was concluded that new water wells will need to be completed at various depths. Data were presented for aquifers and nest wells. refs., tabs., figs

  18. Quantitative estimation of groundwater recharge with special reference to the use of natural radioactive isotopes and hydrological simulation

    International Nuclear Information System (INIS)

    Bredenkamp, D.B.

    1978-01-01

    Methods of quantitative estimation of groundwater recharge have been estimated to 1) illustrate uncertainties associated with methods usually applied 2) indicate some of the simplifying assumptions inherent to a specific method 3) propagate the use of more than one technique in order to improve the reliability of the combined recharge estimate and 4) propose a hydrological model by which the annual recharge and annual variability of recharge could be ascertained. Classical methods such as the water balance equation and flow nets have been reviewed. The use of environmental tritium and radiocarbon have been illustrated as a means of obaining qualitative answers to the occurence of recharge and in revealing the effective mechanism of groundwater recharge through the soil. Quantitative estimation of recharge from the ratio of recharge to storage have been demonstrated for the Kuruman recharge basin. Methods of interpreting tritium profiles in order to obtain a quantitative estimate of recharge have been shown with application of the technique for Rietondale and a dolomitic aquifer in the Western Transvaal. The major part of the thesis has been devoted to the use of hydrological model as a means of estimating groundwater recharge. Subsequent to a general discussion of the conceptual logic, various models have been proposed and tested

  19. Spatial and Temporal Variability of Groundwater Recharge in a Sandstone Aquifer in a Semi-Arid Region

    Science.gov (United States)

    Manna, F.; Murray, S.; Abbey, D.; Martin, P.; Cherry, J.; Parker, B. L.

    2017-12-01

    Groundwater recharge estimates are required to constrain groundwater fluxes over a 11.5 km2 site, located on an upland ridge of southern California. The site is a decommissioned industrial research facility that features chemical contamination of the underlying sedimentary bedrock aquifer and recharge values are necessary to quantify the volumetric flow rate available to transport contaminants. As a first step to assess recharge, Manna et al. (2016) used to chloride mass balance method based on on-site measurements of bulk atmospheric chloride deposition comprised of dry fallout and precipitation, 1490 groundwater samples, and measurements of chloride in surface water runoff. However, this study only provided site-wide long-term average value and did not address spatial and temporal variability of recharge. To this purpose, a spatially distributed hydrological model was used to reflect the site-specific conditions and represent the transient nature of recharge, runoff, storage and evapotranspiration over a 20-year period in a catchment (2.16 km2) of the study area. The integrated model was developed using MIKESHE employing a 20 by 20 m finite difference grid and using on-site measured physical and hydrological input parameters. We found that recharge is highly variable across the study area, with values that span over three orders of magnitude. The main factors affecting recharge are land use and topography: lower recharge values were found in vegetated areas, whereas higher values were found in areas with exposed bedrock at the surface and along the main drainages of the catchment. Analyzing the seasonal variability of the water budget components, evapotranspiration is the dominant process throughout the year and recharge occurs episodically only during the winter season. These results are validated by the comparison of measured and simulated water levels and overland flow rates and are consistent with a previous study carried out at the site using the chloride

  20. Optimal estimation of spatially variable recharge and transmissivity fields under steady-state groundwater flow. Part 2. Case study

    Science.gov (United States)

    Graham, Wendy D.; Neff, Christina R.

    1994-05-01

    The first-order analytical solution of the inverse problem for estimating spatially variable recharge and transmissivity under steady-state groundwater flow, developed in Part 1 is applied to the Upper Floridan Aquifer in NE Florida. Parameters characterizing the statistical structure of the log-transmissivity and head fields are estimated from 152 measurements of transmissivity and 146 measurements of hydraulic head available in the study region. Optimal estimates of the recharge, transmissivity and head fields are produced throughout the study region by conditioning on the nearest 10 available transmissivity measurements and the nearest 10 available head measurements. Head observations are shown to provide valuable information for estimating both the transmissivity and the recharge fields. Accurate numerical groundwater model predictions of the aquifer flow system are obtained using the optimal transmissivity and recharge fields as input parameters, and the optimal head field to define boundary conditions. For this case study, both the transmissivity field and the uncertainty of the transmissivity field prediction are poorly estimated, when the effects of random recharge are neglected.

  1. Isotope investigation on groundwater recharge and dynamics in shallow and deep alluvial aquifers of southwest Punjab.

    Science.gov (United States)

    Keesari, Tirumalesh; Sharma, Diana A; Rishi, Madhuri S; Pant, Diksha; Mohokar, Hemant V; Jaryal, Ajay Kumar; Sinha, U K

    2017-11-01

    Groundwater samples collected from the alluvial aquifers of southwest Punjab, both shallow and deep zones were measured for environmental tritium ( 3 H) and stable isotopes ( 2 H and 18 O) to evaluate the source of recharge and aquifer dynamics. The shallow groundwater shows wide variation in isotopic signature (δ 18 O: -11.3 to -5.0‰) reflecting multiple sources of recharge. The average isotopic signature of shallow groundwaters (δ 18 O: -6.73 ± 1.03‰) is similar to that of local precipitation (-6.98 ± 1.66‰) indicating local precipitation contributes to a large extent compared to other sources. Other sources have isotopically distinct signatures due to either high altitude recharge (canal sources) or evaporative enrichment (irrigation return flow). Deep groundwater shows relatively depleted isotopic signature (δ 18 O: -8.6‰) and doesn't show any evaporation effect as compared to shallow zone indicating recharge from precipitation occurring at relatively higher altitudes. Environmental tritium indicates that both shallow ( 3 H: 5 - 10 T.U.) and deeper zone ( 3 H: 1.5 - 2.5 T.U.) groundwaters are modern. In general the inter-aquifer connections seem to be unlikely except a few places. Environmental isotope data suggests that shallow groundwater is dynamic, local and prone to changes in land use patterns while deep zone water is derived from distant sources, less dynamic and not impacted by surface manifestations. A conceptual groundwater flow diagram is presented. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Effects of recharge, Upper Floridan aquifer heads, and time scale on simulated ground-water exchange with Lake Starr, a seepage lake in central Florida

    Science.gov (United States)

    Swancar, Amy; Lee, Terrie Mackin

    2003-01-01

    Lake Starr and other lakes in the mantled karst terrain of Florida's Central Lake District are surrounded by a conductive surficial aquifer system that receives highly variable recharge from rainfall. In addition, downward leakage from these lakes varies as heads in the underlying Upper Floridan aquifer change seasonally and with pumpage. A saturated three-dimensional finite-difference ground-water flow model was used to simulate the effects of recharge, Upper Floridan aquifer heads, and model time scale on ground-water exchange with Lake Starr. The lake was simulated as an active part of the model using high hydraulic conductivity cells. Simulated ground-water flow was compared to net ground-water flow estimated from a rigorously derived water budget for the 2-year period August 1996-July 1998. Calibrating saturated ground-water flow models with monthly stress periods to a monthly lake water budget will result in underpredicting gross inflow to, and leakage from, ridge lakes in Florida. Underprediction of ground-water inflow occurs because recharge stresses and ground-water flow responses during rainy periods are averaged over too long a time period using monthly stress periods. When inflow is underestimated during calibration, leakage also is underestimated because inflow and leakage are correlated if lake stage is maintained over the long term. Underpredicted leakage reduces the implied effect of ground-water withdrawals from the Upper Floridan aquifer on the lake. Calibrating the weekly simulation required accounting for transient responses in the water table near the lake that generated the greater range of net ground-water flow values seen in the weekly water budget. Calibrating to the weekly lake water budget also required increasing the value of annual recharge in the nearshore region well above the initial estimate of 35 percent of the rainfall, and increasing the hydraulic conductivity of the deposits around and beneath the lake. To simulate the total

  3. Modeling hydrology, groundwater recharge and non-point nitrate loadings in the Himalayan Upper Yamuna basin.

    Science.gov (United States)

    Narula, Kapil K; Gosain, A K

    2013-12-01

    The mountainous Himalayan watersheds are important hydrologic systems responsible for much of the water supply in the Indian sub-continent. These watersheds are increasingly facing anthropogenic and climate-related pressures that impact spatial and temporal distribution of water availability. This study evaluates temporal and spatial distribution of water availability including groundwater recharge and quality (non-point nitrate loadings) for a Himalayan watershed, namely, the Upper Yamuna watershed (part of the Ganga River basin). The watershed has an area of 11,600 km(2) with elevation ranging from 6300 to 600 m above mean sea level. Soil and Water Assessment Tool (SWAT), a physically-based, time-continuous model, has been used to simulate the land phase of the hydrological cycle, to obtain streamflows, groundwater recharge, and nitrate (NO3) load distributions in various components of runoff. The hydrological SWAT model is integrated with the MODular finite difference groundwater FLOW model (MODFLOW), and Modular 3-Dimensional Multi-Species Transport model (MT3DMS), to obtain groundwater flow and NO3 transport. Validation of various modules of this integrated model has been done for sub-basins of the Upper Yamuna watershed. Results on surface runoff and groundwater levels obtained as outputs from simulation show a good comparison with the observed streamflows and groundwater levels (Nash-Sutcliffe and R(2) correlations greater than +0.7). Nitrate loading obtained after nitrification, denitrification, and NO3 removal from unsaturated and shallow aquifer zones is combined with groundwater recharge. Results for nitrate modeling in groundwater aquifers are compared with observed NO3 concentration and are found to be in good agreement. The study further evaluates the sensitivity of water availability to climate change. Simulations have been made with the weather inputs of climate change scenarios of A2, B2, and A1B for end of the century. Water yield estimates under

  4. Assessing the impact of future climate change on groundwater recharge in Galicia-Costa, Spain

    Science.gov (United States)

    Raposo, Juan Ramón; Dafonte, Jorge; Molinero, Jorge

    2013-03-01

    Climate change can impact the hydrological processes of a watershed and may result in problems with future water supply for large sections of the population. Results from the FP5 PRUDENCE project suggest significant changes in temperature and precipitation over Europe. In this study, the Soil and Water Assessment Tool (SWAT) model was used to assess the potential impacts of climate change on groundwater recharge in the hydrological district of Galicia-Costa, Spain. Climate projections from two general circulation models and eight different regional climate models were used for the assessment and two climate-change scenarios were evaluated. Calibration and validation of the model were performed using a daily time-step in four representative catchments in the district. The effects on modeled mean annual groundwater recharge are small, partly due to the greater stomatal efficiency of plants in response to increased CO2 concentration. However, climate change strongly influences the temporal variability of modeled groundwater recharge. Recharge may concentrate in the winter season and dramatically decrease in the summer-autumn season. As a result, the dry-season duration may be increased on average by almost 30 % for the A2 emission scenario, exacerbating the current problems in water supply.

  5. Sources of groundwater and characteristics of surface-water recharge at Bell, White, and Suwannee Springs, Florida, 2012–13

    Science.gov (United States)

    Stamm, John F.; McBride, W. Scott

    2016-12-21

    Discharge from springs in Florida is sourced from aquifers, such as the Upper Floridan aquifer, which is overlain by an upper confining unit that locally can have properties of an aquifer. Water levels in aquifers are affected by several factors, such as precipitation, recharge, and groundwater withdrawals, which in turn can affect discharge from springs. Therefore, identifying groundwater sources and recharge characteristics can be important in assessing how these factors might affect flows and water levels in springs and can be informative in broader applications such as groundwater modeling. Recharge characteristics include the residence time of water at the surface, apparent age of recharge, and recharge water temperature.The groundwater sources and recharge characteristics of three springs that discharge from the banks of the Suwannee River in northern Florida were assessed for this study: Bell Springs, White Springs, and Suwannee Springs. Sources of groundwater were also assessed for a 150-foot-deep well finished within the Upper Floridan aquifer, hereafter referred to as the UFA well. Water samples were collected for geochemical analyses in November 2012 and October 2013 from the three springs and the UFA well. Samples were analyzed for a suite of major ions, dissolved gases, and isotopes of sulfur, strontium, oxygen, and hydrogen. Daily means of water level and specific conductance at White Springs were continuously recorded from October 2012 through December 2013 by the Suwannee River Water Management District. Suwannee River stage at White Springs was computed on the basis of stage at a U.S. Geological Survey streamgage about 2.4 miles upstream. Water levels in two wells, located about 2.5 miles northwest and 13 miles southeast of White Springs, were also used in the analyses.Major ion concentrations were used to differentiate water from the springs and Upper Floridan aquifer into three groups: Bell Springs, UFA well, and White and Suwannee Springs. When

  6. The effects of model complexity and calibration period on groundwater recharge simulations

    Science.gov (United States)

    Moeck, Christian; Van Freyberg, Jana; Schirmer, Mario

    2017-04-01

    A significant number of groundwater recharge models exist that vary in terms of complexity (i.e., structure and parametrization). Typically, model selection and conceptualization is very subjective and can be a key source of uncertainty in the recharge simulations. Another source of uncertainty is the implicit assumption that model parameters, calibrated over historical periods, are also valid for the simulation period. To the best of our knowledge there is no systematic evaluation of the effect of the model complexity and calibration strategy on the performance of recharge models. To address this gap, we utilized a long-term recharge data set (20 years) from a large weighting lysimeter. We performed a differential split sample test with four groundwater recharge models that vary in terms of complexity. They were calibrated using six calibration periods with climatically contrasting conditions in a constrained Monte Carlo approach. Despite the climatically contrasting conditions, all models performed similarly well during the calibration. However, during validation a clear effect of the model structure on model performance was evident. The more complex, physically-based models predicted recharge best, even when calibration and prediction periods had very different climatic conditions. In contrast, more simplistic soil-water balance and lumped model performed poorly under such conditions. For these models we found a strong dependency on the chosen calibration period. In particular, our analysis showed that this can have relevant implications when using recharge models as decision-making tools in a broad range of applications (e.g. water availability, climate change impact studies, water resource management, etc.).

  7. Startup Report for Ground Water Extraction, Treatment, and Recharge System

    National Research Council Canada - National Science Library

    Lamb, Steve

    1997-01-01

    The document presents startup procedures, observations and measurements conducted during the startup of the Groundwater Extraction, Treatment and Recharge System, built for the 162nd Fighter Wing, Air...

  8. Estimation of Groundwater Recharge at Pahute Mesa using the Chloride Mass-Balance Method

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, Clay A [DRI; Hershey, Ronald L [DRI; Healey, John M [DRI; Lyles, Brad F [DRI

    2013-07-01

    Groundwater recharge on Pahute Mesa was estimated using the chloride mass-balance (CMB) method. This method relies on the conservative properties of chloride to trace its movement from the atmosphere as dry- and wet-deposition through the soil zone and ultimately to the saturated zone. Typically, the CMB method assumes no mixing of groundwater with different chloride concentrations; however, because groundwater is thought to flow into Pahute Mesa from valleys north of Pahute Mesa, groundwater flow rates (i.e., underflow) and chloride concentrations from Kawich Valley and Gold Flat were carefully considered. Precipitation was measured with bulk and tipping-bucket precipitation gauges installed for this study at six sites on Pahute Mesa. These data, along with historical precipitation amounts from gauges on Pahute Mesa and estimates from the PRISM model, were evaluated to estimate mean annual precipitation. Chloride deposition from the atmosphere was estimated by analyzing quarterly samples of wet- and dry-deposition for chloride in the bulk gauges and evaluating chloride wet-deposition amounts measured at other locations by the National Atmospheric Deposition Program. Mean chloride concentrations in groundwater were estimated using data from the UGTA Geochemistry Database, data from other reports, and data from samples collected from emplacement boreholes for this study. Calculations were conducted assuming both no underflow and underflow from Kawich Valley and Gold Flat. Model results estimate recharge to be 30 mm/yr with a standard deviation of 18 mm/yr on Pahute Mesa, for elevations >1800 m amsl. These estimates assume Pahute Mesa recharge mixes completely with underflow from Kawich Valley and Gold Flat. The model assumes that precipitation, chloride concentration in bulk deposition, underflow and its chloride concentration, have been constant over the length of time of recharge.

  9. A simple daily soil-water balance model for estimating the spatial and temporal distribution of groundwater recharge in temperate humid areas

    Science.gov (United States)

    Dripps, W.R.; Bradbury, K.R.

    2007-01-01

    Quantifying the spatial and temporal distribution of natural groundwater recharge is usually a prerequisite for effective groundwater modeling and management. As flow models become increasingly utilized for management decisions, there is an increased need for simple, practical methods to delineate recharge zones and quantify recharge rates. Existing models for estimating recharge distributions are data intensive, require extensive parameterization, and take a significant investment of time in order to establish. The Wisconsin Geological and Natural History Survey (WGNHS) has developed a simple daily soil-water balance (SWB) model that uses readily available soil, land cover, topographic, and climatic data in conjunction with a geographic information system (GIS) to estimate the temporal and spatial distribution of groundwater recharge at the watershed scale for temperate humid areas. To demonstrate the methodology and the applicability and performance of the model, two case studies are presented: one for the forested Trout Lake watershed of north central Wisconsin, USA and the other for the urban-agricultural Pheasant Branch Creek watershed of south central Wisconsin, USA. Overall, the SWB model performs well and presents modelers and planners with a practical tool for providing recharge estimates for modeling and water resource planning purposes in humid areas. ?? Springer-Verlag 2007.

  10. Estimating the spatial distribution of artificial groundwater recharge using multiple tracers.

    Science.gov (United States)

    Moeck, Christian; Radny, Dirk; Auckenthaler, Adrian; Berg, Michael; Hollender, Juliane; Schirmer, Mario

    2017-10-01

    Stable isotopes of water, organic micropollutants and hydrochemistry data are powerful tools for identifying different water types in areas where knowledge of the spatial distribution of different groundwater is critical for water resource management. An important question is how the assessments change if only one or a subset of these tracers is used. In this study, we estimate spatial artificial infiltration along an infiltration system with stage-discharge relationships and classify different water types based on the mentioned hydrochemistry data for a drinking water production area in Switzerland. Managed aquifer recharge via surface water that feeds into the aquifer creates a hydraulic barrier between contaminated groundwater and drinking water wells. We systematically compare the information from the aforementioned tracers and illustrate differences in distribution and mixing ratios. Despite uncertainties in the mixing ratios, we found that the overall spatial distribution of artificial infiltration is very similar for all the tracers. The highest infiltration occurred in the eastern part of the infiltration system, whereas infiltration in the western part was the lowest. More balanced infiltration within the infiltration system could cause the elevated groundwater mound to be distributed more evenly, preventing the natural inflow of contaminated groundwater. Dedicated to Professor Peter Fritz on the occasion of his 80th birthday.

  11. Assessing the changes of groundwater recharge / irrigation water use between SRI and traditional irrigation schemes in Central Taiwan

    Science.gov (United States)

    Chen, Shih-Kai; Jang, Cheng-Shin; Tsai, Cheng-Bin

    2015-04-01

    To respond to agricultural water shortage impacted by climate change without affecting rice yield in the future, the application of water-saving irrigation, such as SRI methodology, is considered to be adopted in rice-cultivation in Taiwan. However, the flooded paddy fields could be considered as an important source of groundwater recharge in Central Taiwan. The water-saving benefit of this new methodology and its impact on the reducing of groundwater recharge should be integrally assessed in this area. The objective of this study was to evaluate the changes of groundwater recharge/ irrigation water use between the SRI and traditional irrigation schemes (continuous irrigation, rotational irrigation). An experimental paddy field located in the proximal area of the Choushui River alluvial fan (the largest groundwater pumping region in Taiwan) was chosen as the study area. The 3-D finite element groundwater model (FEMWATER) with the variable boundary condition analog functions, was applied in simulating groundwater recharge process and amount under traditional irrigation schemes and SRI methodology. The use of effective rainfall was taken into account or not in different simulation scenarios for each irrigation scheme. The simulation results showed that there were no significant variations of infiltration rate in the use of effective rainfall or not, but the low soil moisture setting in deep soil layers resulted in higher infiltration rate. Taking the use of effective rainfall into account, the average infiltration rate for continuous irrigation, rotational irrigation, and SRI methodology in the first crop season of 2013 were 4.04 mm/day, 4.00 mm/day and 3.92 mm/day, respectively. The groundwater recharge amount of SRI methodology was slightly lower than those of traditional irrigation schemes, reducing 4% and 2% compared with continuous irrigation and rotational irrigation, respectively. The field irrigation requirement amount of SRI methodology was significantly

  12. Quantification of groundwater recharge through application of pilot techniques in the unsaturated zone.

    Science.gov (United States)

    Kallioras, Andreas; Piepenbrink, Matthias; Schuth, Christoph; Pfletschinger, Heike; Dietrich, Peter; Koeniger, Franz; Rausch, Randolf

    2010-05-01

    Accurate determination of groundwater recharge is a key issue for the "smart mining" of groundwater resources. Groundwater recharge estimation techniques depend on the investigated hydrologic zone, and therefore main approaches are based on (a) unsaturated zone, (b) saturated zone and (c) surface water studies. This research contributes to the determination of groundwater recharge by investigating the infiltration of groundwater through the unsaturated zone. The investigations are conducted through the application of a combination of different pilot field as well as lab techniques. The field techniques include the installation of specially designed Time Domain Reflectometry (TDR) sensors, at different depths within the unsaturated zone for in-situ and continuous measurements of the volumetric pore water content. Additionally, the extraction of pore water -for analysis of its isotopic composition- from multilevel undisturbed soil samples through significant depths within the unsaturated zone column, enables the dating of the groundwater age through the determination of its isotopic composition. The in-situ investigation of the unsaturated zone is complemented by the determination of high resolution temperature profiles. The installation of the pilot TDR sensors is achieved by using direct push methods at significant depths within the unsaturated zone, providing continuous readings of the soil moisture content. The direct push methods are also ideal for multilevel sampling of undisturbed -without using any drilling fluids which affect the isotopic composition of the containing pore water- soil and consequent extraction of the included pore water for further isotopic determination. The pore water is extracted by applying the method of azeotropic distillation; a method which has the least isotopic fractionation effects on groundwater samples. The determination of different isotopic signals such as 18O, 2H, 3H, and 36Cl, aims to the investigation of groundwater transit

  13. Use of Multi-class Empirical Orthogonal Function for Identification of Hydrogeological Parameters and Spatiotemporal Pattern of Multiple Recharges in Groundwater Modeling

    Science.gov (United States)

    Huang, C. L.; Hsu, N. S.; Yeh, W. W. G.; Hsieh, I. H.

    2017-12-01

    This study develops an innovative calibration method for regional groundwater modeling by using multi-class empirical orthogonal functions (EOFs). The developed method is an iterative approach. Prior to carrying out the iterative procedures, the groundwater storage hydrographs associated with the observation wells are calculated. The combined multi-class EOF amplitudes and EOF expansion coefficients of the storage hydrographs are then used to compute the initial gauss of the temporal and spatial pattern of multiple recharges. The initial guess of the hydrogeological parameters are also assigned according to in-situ pumping experiment. The recharges include net rainfall recharge and boundary recharge, and the hydrogeological parameters are riverbed leakage conductivity, horizontal hydraulic conductivity, vertical hydraulic conductivity, storage coefficient, and specific yield. The first step of the iterative algorithm is to conduct the numerical model (i.e. MODFLOW) by the initial guess / adjusted values of the recharges and parameters. Second, in order to determine the best EOF combination of the error storage hydrographs for determining the correction vectors, the objective function is devised as minimizing the root mean square error (RMSE) of the simulated storage hydrographs. The error storage hydrograph are the differences between the storage hydrographs computed from observed and simulated groundwater level fluctuations. Third, adjust the values of recharges and parameters and repeat the iterative procedures until the stopping criterion is reached. The established methodology was applied to the groundwater system of Ming-Chu Basin, Taiwan. The study period is from January 1st to December 2ed in 2012. Results showed that the optimal EOF combination for the multiple recharges and hydrogeological parameters can decrease the RMSE of the simulated storage hydrographs dramatically within three calibration iterations. It represents that the iterative approach that

  14. Lithologic influences on groundwater recharge through incised glacial till from profile to regional scales: Evidence from glaciated Eastern Nebraska

    Science.gov (United States)

    Gates, John B.; Steele, Gregory V.; Nasta, Paolo; Szilagyi, Jozsef

    2014-01-01

    Variability in sediment hydraulic properties associated with landscape depositional and erosional features can influence groundwater recharge processes by affecting soil-water storage and transmission. This study considers recharge to aquifers underlying river-incised glaciated terrain where the distribution of clay-rich till is largely intact in upland locations but has been removed by alluvial erosion in stream valleys. In a stream-dissected glacial region in eastern Nebraska (Great Plains region of the United States), recharge estimates were developed for nested profile, aquifer, and regional scales using unsaturated zone profile measurements (matric potentials, Cl- and 3H), groundwater tracers (CFC-12 and SF6), and a remote sensing-assisted water balance model. Results show a consistent influence of till lithology on recharge rates across nested spatial scales despite substantial uncertainty in all recharge estimation methods, suggesting that minimal diffuse recharge occurs through upland glacial till lithology whereas diffuse recharge occurs in river valleys where till is locally absent. Diffuse recharge is estimated to account for a maximum of 61% of total recharge based on comparison of diffuse recharge estimated from the unsaturated zone (0-43 mm yr-1) and total recharge estimated from groundwater tracers (median 58 mm yr-1) and water balance modeling (median 56 mm yr-1). The results underscore the importance of lithologic controls on the distributions of both recharge rates and mechanisms.

  15. An approach to identify urban groundwater recharge

    Directory of Open Access Journals (Sweden)

    E. Vázquez-Suñé

    2010-10-01

    Full Text Available Evaluating the proportion in which waters from different origins are mixed in a given water sample is relevant for many hydrogeological problems, such as quantifying total recharge, assessing groundwater pollution risks, or managing water resources. Our work is motivated by urban hydrogeology, where waters with different chemical signature can be identified (losses from water supply and sewage networks, infiltration from surface runoff and other water bodies, lateral aquifers inflows, .... The relative contribution of different sources to total recharge can be quantified by means of solute mass balances, but application is hindered by the large number of potential origins. Hence, the need to incorporate data from a large number of conservative species, the uncertainty in sources concentrations and measurement errors. We present a methodology to compute mixing ratios and end-members composition, which consists of (i Identification of potential recharge sources, (ii Selection of tracers, (iii Characterization of the hydrochemical composition of potential recharge sources and mixed water samples, and (iv Computation of mixing ratios and reevaluation of end-members. The analysis performed in a data set from samples of the Barcelona city aquifers suggests that the main contributors to total recharge are the water supply network losses (22%, the sewage network losses (30%, rainfall, concentrated in the non-urbanized areas (17%, from runoff infiltration (20%, and the Besòs River (11%. Regarding species, halogens (chloride, fluoride and bromide, sulfate, total nitrogen, and stable isotopes (18O, 2H, and 34S behaved quite conservatively. Boron, residual alkalinity, EDTA and Zn did not. Yet, including these species in the computations did not affect significantly the proportion estimations.

  16. An approach to delineate groundwater recharge potential sites in Ambalantota, Sri Lanka using GIS techniques

    Directory of Open Access Journals (Sweden)

    I.P. Senanayake

    2016-01-01

    Full Text Available The demand for fresh water in Hambantota District, Sri Lanka is rapidly increasing with the enormous amount of ongoing development projects in the region. Nevertheless, the district experiences periodic water stress conditions due to seasonal precipitation patterns and scarcity of surface water resources. Therefore, management of available groundwater resources is critical, to fulfil potable water requirements in the area. However, exploitation of groundwater should be carried out together with artificial recharging in order to maintain the long term sustainability of water resources. In this study, a GIS approach was used to delineate potential artificial recharge sites in Ambalantota area within Hambantota. Influential thematic layers such as rainfall, lineament, slope, drainage, land use/land cover, lithology, geomorphology and soil characteristics were integrated by using a weighted linear combination method. Results of the study reveal high to moderate groundwater recharge potential in approximately 49% of Ambalantota area.

  17. Groundwater and climate change in Africa : review of recharge studies

    OpenAIRE

    Bonsor, H.C.; MacDonald, A.M.

    2010-01-01

    The review of recharge studies was conducted as part of a one year DFID-funded research programme, aimed at improving understanding of the impacts of climate change on groundwater resources and local livelihoods – see http://www.bgs.ac.uk/GWResilience/. The review is one of a series of components within the project. The overall outputs of the project are: Two hydrogeological case studies in West and East Africa – which assess the storage and availability of groundwater in different aquifers a...

  18. Modeling and Optimization of Recycled Water Systems to Augment Urban Groundwater Recharge through Underutilized Stormwater Spreading Basins.

    Science.gov (United States)

    Bradshaw, Jonathan L; Luthy, Richard G

    2017-10-17

    Infrastructure systems that use stormwater and recycled water to augment groundwater recharge through spreading basins represent cost-effective opportunities to diversify urban water supplies. However, technical questions remain about how these types of managed aquifer recharge systems should be designed; furthermore, existing planning tools are insufficient for performing robust design comparisons. Addressing this need, we present a model for identifying the best-case design and operation schedule for systems that deliver recycled water to underutilized stormwater spreading basins. Resulting systems are optimal with respect to life cycle costs and water deliveries. Through a case study of Los Angeles, California, we illustrate how delivering recycled water to spreading basins could be optimally implemented. Results illustrate trade-offs between centralized and decentralized configurations. For example, while a centralized Hyperion system could deliver more recycled water to the Hansen Spreading Grounds, this system incurs approximately twice the conveyance cost of a decentralized Tillman system (mean of 44% vs 22% of unit life cycle costs). Compared to existing methods, our model allows for more comprehensive and precise analyses of cost, water volume, and energy trade-offs among different design scenarios. This model can inform decisions about spreading basin operation policies and the development of new water supplies.

  19. Evaluation of the potential impact of climate changes on groundwater recharge in Karkheh river basin (Khuzestan, Iran)

    Science.gov (United States)

    Abrishamchi, A.; Beigi, E.; Tajrishy, M.; Abrishamchi, A.

    2009-12-01

    Groundwater is an important natural resource for human beings and ecosystems, especially in arid semi arid regions with scarce water resources and high climate variability. This vital resource is under stress in terms of both quantity and quality due to increased demands as well as the drought. Wise groundwater management requires vulnerability and susceptibility assessment of groundwater resources to natural and anthropogenic phenomena such as drought, over-abstraction and quality deterioration both in the current climatic situation and in the context of climate change. There is enough evidence that climate change is expected to affect all elements of hydrologic cycle and have negative effects on water resources due to increased variability in extreme hydrologic events of droughts and floods. .In this study impact of climate change on groundwater recharge in Karkheh river basin in province of Khuzestan, Iran, has been investigated using a physically-based methodology that can be used for predicting both temporal and spatial varying groundwater recharge. To ensure the sustainability of the land and water resources developments, assessment of the possible impacts of climate change on hydrology and water resources in the basin is necessary. Quantifying groundwater recharge is essential for management of groundwater resources. Recharge was estimated by using the hydrological evaluation of landfill performance (HELP3) water budget model. Model’s parameters were calibrated and validated using observational data in 1990-1998. The impact of climate change was modeled using downscaled precipitation and temperature from runs of CGCM2 model. These data were derived from two scenarios, A2 and B2 for three periods: 2010-2039, 2040-2069, and 2070-2099. Results of the study indicate that due to global warming evapotranspiration rates will increase and winter-precipitation will fall, spring-snowmelt will shift toward winter and consequently it will cause recharge to increase

  20. Effects of Sea Level Rise on Groundwater Flow Paths in a Coastal Aquifer System

    Science.gov (United States)

    Morrissey, S. K.; Clark, J. F.; Bennett, M. W.; Richardson, E.; Stute, M.

    2008-05-01

    Changes in groundwater flow in the Floridan aquifer system, South Florida, from the rise in sea level at the end of the last glacial period may be indicative of changes coastal aquifers will experience with continued sea level rise. As sea level rises, the hydraulic head near the coast increases. Coastal aquifers can therefore experience decreased groundwater gradients (increased residence times) and seawater intrusion. Stable isotopes of water, dissolved noble gas temperatures, radiocarbon and He concentrations were analyzed in water collected from 68 wells in the Floridan aquifer system throughout South Florida. Near the recharge area, geochemical data along groundwater flow paths in the Upper Floridan aquifer show a transition from recently recharged groundwater to glacial-aged water. Down gradient from this transition, little variation is apparent in the stable isotopes and noble gas recharge temperatures, indicating that most of the Upper Floridan aquifer contains groundwater recharged during the last glacial period. The rapid 120-meter rise in sea level marking the end of the last glacial period increased the hydraulic head in the Floridan aquifer system near the coast, slowing the flow of groundwater from the recharge area to the ocean and trapping glacial-aged groundwater. The raised sea level also flooded half of the Florida platform and caused seawater to intrude into the Lower Floridan. This circulation of seawater in the Lower Floridan continues today as our data indicate that the groundwater is similar to modern seawater with a freshwater component entering vertically from the recharge area to the Upper Floridan.

  1. Oxygen isotope composition as late glacial palaeoclimate indicators of groundwater recharge in the Baltic Basin

    International Nuclear Information System (INIS)

    Mokrik, R.; Mazeika, J.

    2002-01-01

    Several hypotheses were established to explain low δ 18 O values of groundwater which have been found in the Estonian Homocline. Traces of depleted groundwater were found also in other parts of the Baltic Basin near the shoreline. From data collected in this and previous studies, the δ 18 O values of groundwater in most aquifers are known to range from -7.7 to -13.9 per mille. However, the groundwater in Estonia in the Cambrian-Vendian aquifer system has significantly lower δ 18 O values, which vary mainly from -18 to -22.5 per mille. The overlying Ordovician-Cambrian aquifer is also depleted in 18 O, but, as a rule, the degree of depletion is several per mille less than in case of the Cambrian- Vendian aquifer. The thickness of the depleted water in Estonia reaches 450 m. At similar depths beneath Gotland Island (Sweden Homocline), groundwater has significantly higher δ 18 O values (from -5.7 to -6.1 per mille). A hydrogeologic model, depicting conditions during the pre Late Glacial, and accounting for hydraulic connections between the lake and river systems through taliks in permafrost, was developed to explain the observed groundwater isotope data. According to the adopted model, penetration of isotopically depleted surface waters could have reached depths of up to 500 m, with subsequent mixing between subglacial meltwater and old groundwater of Huneborg-Denekamp time. Traces of this penetration were discovered only near the shoreline, where δ 18 O values vary from -12 to -13.9 per mille and 14 C is below 4%. In the territory of the Estonian Homocline, the hydraulically close connection via the Cambrian-Vendian aquifer between talik systems of the Gulf of Riga and the Gulf of Finland existed through permafrost before the Late Glacial. This was due to subglacial recharge during the recessional Pandivere (12 ka BP) and Palivere (11.2 ka BP) phases, which is also associated with recharge of isotopically depleted groundwater. (author)

  2. Evapotranspiration Dynamics and Effects on Groundwater Recharge and Discharge at the Tuba City, Arizona, Disposal Site

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2016-02-01

    The U.S. Department of Energy Office of Legacy Management is evaluating groundwater flow and contaminant transport at a former uranium mill site near Tuba City, Arizona. We estimated effects of temporal and spatial variability in evapotranspiration (ET) on recharge and discharge within a groundwater model domain (GMD) as part of this evaluation. We used remote sensing algorithms and precipitation (PPT) data to estimate ET and the ET/PPT ratios within the 3531 hectare GMD. For the period from 2000 to 2012, ET and PPT were nearly balanced (129 millimeters per year [mm yr-1] and 130 mm yr-1, respectively; ET/PPT = 0.99). However, seasonal and annual variability in ET and PPT were out of phase, and spatial variability in vegetation differentiated discharge and recharge areas within the GMD. Half of ET occurred during spring and early summer when PPT was low, and about 70% of PPT arriving in fall and winter was discharged as plant transpiration in the spring and summer period. Vegetation type and health had a significant effect on the site water balance. Plant cover and ET were significantly higher (1) during years of lighter compared to years of heavier grazing pressure, and (2) on rangeland protected from grazing compared to rangeland grazed by livestock. Heavy grazing increased groundwater recharge (PPT > ET over the 13-year period). Groundwater discharge (ET > PPT over the 13-year period) was highest in riparian phreatophyte communities but insignificant in desert phreatophyte communities impacted by heavy grazing. Grazing management in desert upland and phreatophyte communities may result in reduced groundwater recharge, increased groundwater discharge, and could be used to influence local groundwater flow.

  3. Impact of coastal forcing and groundwater recharge on the growth of a fresh groundwater lens in a mega-scale beach nourishment

    Science.gov (United States)

    Huizer, Sebastian; Radermacher, Max; de Vries, Sierd; Oude Essink, Gualbert H. P.; Bierkens, Marc F. P.

    2018-02-01

    For a large beach nourishment called the Sand Engine - constructed in 2011 at the Dutch coast - we have examined the impact of coastal forcing (i.e. natural processes that drive coastal hydro- and morphodynamics) and groundwater recharge on the growth of a fresh groundwater lens between 2011 and 2016. Measurements of the morphological change and the tidal dynamics at the study site were incorporated in a calibrated three-dimensional and variable-density groundwater model of the study area. Simulations with this model showed that the detailed incorporation of both the local hydro- and morphodynamics and the actual recharge rate can result in a reliable reconstruction of the growth in fresh groundwater resources. In contrast, the neglect of tidal dynamics, land-surface inundations, and morphological changes in model simulations can result in considerable overestimations of the volume of fresh groundwater. In particular, wave runup and coinciding coastal erosion during storm surges limit the growth in fresh groundwater resources in dynamic coastal environments, and should be considered at potential nourishment sites to delineate the area that is vulnerable to salinization.

  4. Irrigated agriculture and future climate change effects on groundwater recharge, northern High Plains aquifer, USA

    Science.gov (United States)

    Lauffenburger, Zachary H.; Gurdak, Jason J.; Hobza, Christopher M.; Woodward, Duane; Wolf, Cassandra

    2018-01-01

    Understanding the controls of agriculture and climate change on recharge rates is critically important to develop appropriate sustainable management plans for groundwater resources and coupled irrigated agricultural systems. In this study, several physical (total potential (ψT) time series) and chemical tracer and dating (3H, Cl−, Br−, CFCs, SF6, and 3H/3He) methods were used to quantify diffuse recharge rates beneath two rangeland sites and irrigation recharge rates beneath two irrigated corn sites along an east-west (wet-dry) transect of the northern High Plains aquifer, Platte River Basin, central Nebraska. The field-based recharge estimates and historical climate were used to calibrate site-specific Hydrus-1D models, and irrigation requirements were estimated using the Crops Simulation Model (CROPSIM). Future model simulations were driven by an ensemble of 16 global climate models and two global warming scenarios to project a 2050 climate relative to the historical baseline 1990 climate, and simulate changes in precipitation, irrigation, evapotranspiration, and diffuse and irrigation recharge rates. Although results indicate statistical differences between the historical variables at the eastern and western sites and rangeland and irrigated sites, the low warming scenario (+1.0 °C) simulations indicate no statistical differences between 2050 and 1990. However, the high warming scenarios (+2.4 °C) indicate a 25% and 15% increase in median annual evapotranspiration and irrigation demand, and decreases in future diffuse recharge by 53% and 98% and irrigation recharge by 47% and 29% at the eastern and western sites, respectively. These results indicate an important threshold between the low and high warming scenarios that if exceeded could trigger a significant bidirectional shift in 2050 hydroclimatology and recharge gradients. The bidirectional shift is that future northern High Plains temperatures will resemble present central High Plains

  5. Conceptual model of recharge to southeastern Badain Jaran Desert groundwater and lakes from environmental tracers

    International Nuclear Information System (INIS)

    Gates, John B; Edmunds, W Mike; Darling, W George; Ma Jinzhu; Pang Zhonghe; Young, Adam A

    2008-01-01

    Sources of groundwater recharge to the Badain Jaran Desert in China have been investigated using geochemical and isotopic techniques. Stable isotope compositions (δ 18 O and δ 2 H) of shallow groundwater and surface water from oasis lakes evolve from a starting composition considerably depleted compared to local unsaturated zone moisture, confirming inferences from chloride mass balance that direct infiltration of precipitation is not a volumetrically important source of recharge to the shallow aquifer in the study area. Shallow phreatic and deeper confined groundwater bodies appear unconnected based on chemical composition and radiocarbon activities. Hydrogeologic evidence points toward a bordering mountain range (Yabulai) as a likely recharge zone, which is consistent with tracer results. A mean residence time in the range of 1-2 ka for the desert's southeastern margin is inferred from radiocarbon. These results reveal that some replenishment to the desert aquifer is occurring but at a rate much lower than previously suggested, which is relevant for water resources planning in this ecologically sensitive area

  6. Recharge processes and vertical transfer investigated through long-term monitoring of dissolved gases in shallow groundwater

    Science.gov (United States)

    de Montety, V.; Aquilina, L.; Labasque, T.; Chatton, E.; Fovet, O.; Ruiz, L.; Fourré, E.; de Dreuzy, J. R.

    2018-05-01

    We investigated temporal variations and vertical evolution of dissolved gaseous tracers (CFC-11, CFC-12, SF6, and noble gases), as well as 3H/3He ratio to determine groundwater recharge processes of a shallow unconfined, hard-rock aquifer in an agricultural catchment. We sampled dissolved gas concentration at 4 locations along the hillslope of a small experimental watershed, over 6 hydrological years, between 2 and 6 times per years, for a total of 20 field campaigns. We collected groundwater samples in the fluctuation zone and the permanently saturated zone using piezometers from 5 to 20 m deep. The purpose of this work is i) to assess the benefits of using gaseous tracers like CFCs and SF6 to study very young groundwater with flows suspected to be heterogeneous and variable in time, ii) to characterize the processes that control dissolved gas concentrations in groundwater during the recharge of the aquifer, and iii) to understand the evolution of recharge flow processes by repeated measurement campaigns, taking advantage of a long monitoring in a site devoted to recharge processes investigation. Gas tracer profiles are compared at different location of the catchment and for different hydrologic conditions. In addition, we compare results from CFCs and 3H/3He analysis to define the flow model that best explains tracer concentrations. Then we discuss the influence of recharge events on tracer concentrations and residence time and propose a temporal evolution of residence times for the unsaturated zone and the permanently saturated zone. These results are used to gain a better understanding of the conceptual model of the catchment and flow processes especially during recharge events.

  7. Recharge contribution to the Guarani Aquifer System estimated from the water balance method in a representative watershed.

    Science.gov (United States)

    Wendland, Edson; Gomes, Luis H; Troeger, Uwe

    2015-01-01

    The contribution of recharge to regional groundwater flow systems is essential information required to establish sustainable water resources management. The objective of this work was to determine the groundwater outflow in the Ribeirão da Onça Basin using a water balance model of the saturated soil zone. The basin is located in the outcrop region of the Guarani Aquifer System (GAS). The water balance method involved the determination of direct recharge values, groundwater storage variation and base flow. The direct recharge was determined by the water table fluctuation method (WTF). The base flow was calculated by the hydrograph separation method, which was generated by a rain-flow model supported by biweekly streamflow measurements in the control section. Undisturbed soil samples were collected at depths corresponding to the variation zone of the groundwater level to determine the specific yield of the soil (drainable porosity). Water balances were performed in the saturated zone for the hydrological years from February 2004 to January 2007. The direct recharge ranged from 14.0% to 38.0%, and groundwater outflow from 0.4% to 2.4% of the respective rainfall during the same period.

  8. Novel S-35 Intrinsic Tracer Method for Determining Groundwater Travel Time near Managed Aquifer Recharge Facilities

    Science.gov (United States)

    Urióstegui, S. H.; Bibby, R. K.; Esser, B. K.; Clark, J. F.

    2013-12-01

    Identifying groundwater travel times near managed aquifer recharge (MAR) facilities is a high priority for protecting public and environmental health. For MAR facilities in California that incorporate tertiary wastewater into their surface-spreading recharge practices, the target subsurface residence time is >9 months to allow for the natural inactivation and degradation of potential contaminants (less time is needed for full advanced treated water). Established intrinsic groundwater tracer techniques such as tritium/helium-3 dating are unable to resolve timescales of method using a naturally occurring radioisotope of sulfur, sulfur-35 (S-35). After its production in the atmosphere by cosmic ray interaction with argon, S-35 enters the hydrologic cycle as dissolved sulfate through precipitation The short half-life of S-35 (3 months) is ideal for investigating recharge and transport of MAR groundwater on the method, however, has not been applied to MAR operations because of the difficulty in measuring S-35 with sufficient sensitivity in high-sulfate waters. We have developed a new method and have applied it at two southern California MAR facilities where groundwater travel times have previously been characterized using deliberate tracers: 1) Rio Hondo Spreading Grounds in Los Angeles County, and 2) Orange County Groundwater Recharge Facilities in Orange County. Reasonable S-35 travel times of method also identified seasonal patterns in subsurface travel times, which may not be revealed by a deliberate tracer study that is dependent on the hydrologic conditions during the tracer injection period.

  9. Recharge heterogeneity and high intensity rainfall events increase contamination risk for Mediterranean groundwater resources

    Science.gov (United States)

    Hartmann, Andreas; Jasechko, Scott; Gleeson, Tom; Wada, Yoshihide; Andreo, Bartolomé; Barberá, Juan Antonio; Brielmann, Heike; Charlier, Jean-Baptiste; Darling, George; Filippini, Maria; Garvelmann, Jakob; Goldscheider, Nico; Kralik, Martin; Kunstmann, Harald; Ladouche, Bernard; Lange, Jens; Mudarra, Matías; Francisco Martín, José; Rimmer, Alon; Sanchez, Damián; Stumpp, Christine; Wagener, Thorsten

    2017-04-01

    Karst develops through the dissolution of carbonate rock and results in pronounced spatiotemporal heterogeneity of hydrological processes. Karst groundwater in Europe is a major source of fresh water contributing up to half of the total drinking water supply in some countries like Austria or Slovenia. Previous work showed that karstic recharge processes enhance and alter the sensitivity of recharge to climate variability. The enhanced preferential flow from the surface to the aquifer may be followed by enhanced risk of groundwater contamination. In this study we assess the contamination risk of karst aquifers over Europe and the Mediterranean using simulated transit time distributions. Using a new type of semi-distributed model that considers the spatial heterogeneity of karst hydraulic properties, we were able to simulate karstic groundwater recharge including its heterogeneous spatiotemporal dynamics. The model is driven by gridded daily climate data from the Global Land Data Assimilation System (GLDAS). Transit time distributions are calculated using virtual tracer experiments. We evaluated our simulations by independent information on transit times derived from observed time series of water isotopes of >70 karst springs over Europe. The simulations indicate that, compared to humid, mountain and desert regions, the Mediterranean region shows a stronger risk of contamination in Europe because preferential flow processes are most pronounced given thin soil layers and the seasonal abundance of high intensity rainfall events in autumn and winter. Our modelling approach includes strong simplifications and its results cannot easily be generalized but it still highlights that the combined effects of variable climate and heterogeneous catchment properties constitute a strong risk on water quality.

  10. Arid-zone groundwater recharge and palaeorecharge: insights from the radioisotope chlorine-36

    International Nuclear Information System (INIS)

    Jacobson, G.; Wischusen, J.; Cresswell, R.; Fifield, K.

    1998-01-01

    AGSO's collaborative 'Western water' study of groundwater resources in Aboriginal lands in the southwest Northern Territory arid zone, has applied the radioisotope 36 CI and 14 C to investigate the sustainability of community water supplies drawn from shallow aquifers in the Papunya-Kintore-Yuendumu area. The 36 CI results have important implications for groundwater management throughout the arid zone, because substantial recharge occurs only during favourable, wet, interglacial climatic regimes. this has important implications for groundwater management in this area and elsewhere in central Australia, where most of the community water supplies depend on 'old' stored groundwater

  11. Natural recharge estimation and uncertainty analysis of an adjudicated groundwater basin using a regional-scale flow and subsidence model (Antelope Valley, California, USA)

    Science.gov (United States)

    Siade, Adam J.; Nishikawa, Tracy; Martin, Peter

    2015-01-01

    Groundwater has provided 50–90 % of the total water supply in Antelope Valley, California (USA). The associated groundwater-level declines have led the Los Angeles County Superior Court of California to recently rule that the Antelope Valley groundwater basin is in overdraft, i.e., annual pumpage exceeds annual recharge. Natural recharge consists primarily of mountain-front recharge and is an important component of the total groundwater budget in Antelope Valley. Therefore, natural recharge plays a major role in the Court’s decision. The exact quantity and distribution of natural recharge is uncertain, with total estimates from previous studies ranging from 37 to 200 gigaliters per year (GL/year). In order to better understand the uncertainty associated with natural recharge and to provide a tool for groundwater management, a numerical model of groundwater flow and land subsidence was developed. The transient model was calibrated using PEST with water-level and subsidence data; prior information was incorporated through the use of Tikhonov regularization. The calibrated estimate of natural recharge was 36 GL/year, which is appreciably less than the value used by the court (74 GL/year). The effect of parameter uncertainty on the estimation of natural recharge was addressed using the Null-Space Monte Carlo method. A Pareto trade-off method was also used to portray the reasonableness of larger natural recharge rates. The reasonableness of the 74 GL/year value and the effect of uncertain pumpage rates were also evaluated. The uncertainty analyses indicate that the total natural recharge likely ranges between 34.5 and 54.3 GL/year.

  12. Multiple recharge processes to heterogeneous Mediterranean coastal aquifers and implications on recharge rates evolution in time

    Science.gov (United States)

    Santoni, S.; Huneau, F.; Garel, E.; Celle-Jeanton, H.

    2018-04-01

    Climate change is nowadays widely considered to have major effects on groundwater resources. Climatic projections suggest a global increase in evaporation and higher frequency of strong rainfall events especially in Mediterranean context. Since evaporation is synonym of low recharge conditions whereas strong rainfall events are more favourable to recharge in heterogeneous subsurface contexts, a lack of knowledge remains then on the real ongoing and future drinking groundwater supply availability at aquifers scale. Due to low recharge potential and high inter-annual climate variability, this issue is strategic for the Mediterranean hydrosystems. This is especially the case for coastal aquifers because they are exposed to seawater intrusion, sea-level rise and overpumping risks. In this context, recharge processes and rates were investigated in a Mediterranean coastal aquifer with subsurface heterogeneity located in Southern Corsica (France). Aquifer recharge rates from combining ten physical and chemical methods were computed. In addition, hydrochemical and isotopic investigations were carried out through a monthly two years monitoring combining major ions and stable isotopes of water in rain, runoff and groundwater. Diffuse, focused, lateral mountain system and irrigation recharge processes were identified and characterized. A predominant focused recharge conditioned by subsurface heterogeneity is evidenced in agreement with variable but highly favourable recharge rates. The fast water transfer from the surface to the aquifer implied by this recharge process suggests less evaporation, which means higher groundwater renewal and availability in such Mediterranean coastal aquifers.

  13. Recharge sources and residence times of groundwater as determined by geochemical tracers in the Mayfield Area, southwestern Idaho, 2011–12

    Science.gov (United States)

    Hopkins, Candice B.

    2013-01-01

    Parties proposing residential development in the area of Mayfield, Idaho are seeking a sustainable groundwater supply. During 2011–12, the U.S. Geological Survey, in cooperation with the Idaho Department of Water Resources, used geochemical tracers in the Mayfield area to evaluate sources of aquifer recharge and differences in groundwater residence time. Fourteen groundwater wells and one surface-water site were sampled for major ion chemistry, metals, stable isotopes, and age tracers; data collected from this study were used to evaluate the sources of groundwater recharge and groundwater residence times in the area. Major ion chemistry varied along a flow path between deeper wells, suggesting an upgradient source of dilute water, and a downgradient source of more concentrated water with the geochemical signature of the Idaho Batholith. Samples from shallow wells had elevated nutrient concentrations, a more positive oxygen-18 signature, and younger carbon-14 dates than deep wells, suggesting that recharge comes from young precipitation and surface-water infiltration. Samples from deep wells generally had higher concentrations of metals typical of geothermal waters, a more negative oxygen-18 signature, and older carbon-14 values than samples from shallow wells, suggesting that recharge comes from both infiltration of meteoric water and another source. The chemistry of groundwater sampled from deep wells is somewhat similar to the chemistry in geothermal waters, suggesting that geothermal water may be a source of recharge to this aquifer. Results of NETPATH mixing models suggest that geothermal water composes 1–23 percent of water in deep wells. Chlorofluorocarbons were detected in every sample, which indicates that all groundwater samples contain at least a component of young recharge, and that groundwater is derived from multiple recharge sources. Conclusions from this study can be used to further refine conceptual hydrological models of the area.

  14. Incorporation of Satellite Data and Uncertainty in a Nationwide Groundwater Recharge Model in New Zealand

    Directory of Open Access Journals (Sweden)

    Rogier Westerhoff

    2018-01-01

    Full Text Available A nationwide model of groundwater recharge for New Zealand (NGRM, as described in this paper, demonstrated the benefits of satellite data and global models to improve the spatial definition of recharge and the estimation of recharge uncertainty. NGRM was inspired by the global-scale WaterGAP model but with the key development of rainfall recharge calculation on scales relevant to national- and catchment-scale studies (i.e., a 1 km × 1 km cell size and a monthly timestep in the period 2000–2014 provided by satellite data (i.e., MODIS-derived evapotranspiration, AET and vegetation in combination with national datasets of rainfall, elevation, soil and geology. The resulting nationwide model calculates groundwater recharge estimates, including their uncertainty, consistent across the country, which makes the model unique compared to all other New Zealand estimates targeted towards groundwater recharge. At the national scale, NGRM estimated an average recharge of 2500 m 3 /s, or 298 mm/year, with a model uncertainty of 17%. Those results were similar to the WaterGAP model, but the improved input data resulted in better spatial characteristics of recharge estimates. Multiple uncertainty analyses led to these main conclusions: the NGRM model could give valuable initial estimates in data-sparse areas, since it compared well to most ground-observed lysimeter data and local recharge models; and the nationwide input data of rainfall and geology caused the largest uncertainty in the model equation, which revealed that the satellite data could improve spatial characteristics without significantly increasing the uncertainty. Clearly the increasing volume and availability of large-scale satellite data is creating more opportunities for the application of national-scale models at the catchment, and smaller, scales. This should result in improved utility of these models including provision of initial estimates in data-sparse areas. Topics for future

  15. A comparative study of two approaches to analyse groundwater recharge, travel times and nitrate storage distribution at a regional scale

    Science.gov (United States)

    Turkeltaub, T.; Ascott, M.; Gooddy, D.; Jia, X.; Shao, M.; Binley, A. M.

    2017-12-01

    Understanding deep percolation, travel time processes and nitrate storage in the unsaturated zone at a regional scale is crucial for sustainable management of many groundwater systems. Recently, global hydrological models have been developed to quantify the water balance at such scales and beyond. However, the coarse spatial resolution of the global hydrological models can be a limiting factor when analysing regional processes. This study compares simulations of water flow and nitrate storage based on regional and global scale approaches. The first approach was applied over the Loess Plateau of China (LPC) to investigate the water fluxes and nitrate storage and travel time to the LPC groundwater system. Using raster maps of climate variables, land use data and soil parameters enabled us to determine fluxes by employing Richards' equation and the advection - dispersion equation. These calculations were conducted for each cell on the raster map in a multiple 1-D column approach. In the second approach, vadose zone travel times and nitrate storage were estimated by coupling groundwater recharge (PCR-GLOBWB) and nitrate leaching (IMAGE) models with estimates of water table depth and unsaturated zone porosity. The simulation results of the two methods indicate similar spatial groundwater recharge, nitrate storage and travel time distribution. Intensive recharge rates are located mainly at the south central and south west parts of the aquifer's outcrops. Particularly low recharge rates were simulated in the top central area of the outcrops. However, there are significant discrepancies between the simulated absolute recharge values, which might be related to the coarse scale that is used in the PCR-GLOBWB model, leading to smoothing of the recharge estimations. Both models indicated large nitrate inventories in the south central and south west parts of the aquifer's outcrops and the shortest travel times in the vadose zone are in the south central and east parts of the

  16. Recharge and Lateral Groundwater Flow Boundary Conditions for the Saturated Zone Site-Scale Flow and Transport Model

    Energy Technology Data Exchange (ETDEWEB)

    B. Arnold; T. Corbet

    2001-12-18

    The purpose of the flow boundary conditions analysis is to provide specified-flux boundary conditions for the saturated zone (SZ) site-scale flow and transport model. This analysis is designed to use existing modeling and analysis results as the basis for estimated groundwater flow rates into the SZ site-scale model domain, both as recharge at the upper (water table) boundary and as underflow at the lateral boundaries. The objective is to provide consistency at the boundaries between the SZ site-scale flow model and other groundwater flow models. The scope of this analysis includes extraction of the volumetric groundwater flow rates simulated by the SZ regional-scale flow model to occur at the lateral boundaries of the SZ site-scale flow model and the internal qualification of the regional-scale model for use in this analysis model report (AMR). In addition, the scope includes compilation of information on the recharge boundary condition taken from three sources: (1) distributed recharge as taken from the SZ regional-scale flow model, (2) recharge below the area of the unsaturated zone (UZ) site-scale flow model, and (3) focused recharge along the Fortymile Wash channel.

  17. Groundwater vulnerability and recharge or palaeorecharge in the Southeastern Chad Basin, Chari Baguirmi aquifer

    International Nuclear Information System (INIS)

    Djoret, D.; Travi, Y.

    2001-01-01

    Stable isotopes and major chemical elements have been used to investigate present or ancient groundwater renewal in the multilayered aquifer of the Chari-Baguirmi plain, South of Lake Chad. On the Western side, recharge mainly occurs from the Chari River during the flood period. Within the Ndjamena area, the rise of the piezometric level in the contaminated subsurface zone provokes an increase in nitrate concentrations. Rainfall recharge is mainly located close to the outcropping basement, i.e. on the Eastern side of the area and does not occurs in the central part of the plain where groundwater also presents a stronger evaporative signature. This supports the hypothesis attributing a major role to evaporation processes in the formation of piezometric depressions in the Sahel zone. There is no evidence of present day or ancient water recharge from Lake Chad. (author)

  18. Linking denitrification and infiltration rates during managed groundwater recharge.

    Science.gov (United States)

    Schmidt, Calla M; Fisher, Andrew T; Racz, Andrew J; Lockwood, Brian S; Huertos, Marc Los

    2011-11-15

    We quantify relations between rates of in situ denitrification and saturated infiltration through shallow, sandy soils during managed groundwater recharge. We used thermal methods to determine time series of point-specific flow rates, and chemical and isotopic methods to assess denitrification progress. Zero order denitrification rates between 3 and 300 μmol L(-1) d(-1) were measured during infiltration. Denitrification was not detected at times and locations where the infiltration rate exceeded a threshold of 0.7 ± 0.2 m d(-1). Pore water profiles of oxygen and nitrate concentration indicated a deepening of the redoxocline at high flow rates, which reduced the thickness of the zone favorable for denitrification. Denitrification rates were positively correlated with infiltration rates below the infiltration threshold, suggesting that for a given set of sediment characteristics, there is an optimal infiltration rate for achieving maximum nitrate load reduction and improvements to water supply during managed groundwater recharge. The extent to which results from this study may be extended to other managed and natural hydrologic settings remains to be determined, but the approach taken in this study should be broadly applicable, and provides a quantitative link between shallow hydrologic and biogeochemical processes.

  19. Response to recharge variation of thin rainwater lenses and their mixing zone with underlying saline groundwater

    Directory of Open Access Journals (Sweden)

    S. Eeman

    2012-10-01

    Full Text Available In coastal zones with saline groundwater, fresh groundwater lenses may form due to infiltration of rain water. The thickness of both the lens and the mixing zone, determines fresh water availability for plant growth. Due to recharge variation, the thickness of the lens and the mixing zone are not constant, which may adversely affect agricultural and natural vegetation if saline water reaches the root zone during the growing season. In this paper, we study the response of thin lenses and their mixing zone to variation of recharge. The recharge is varied using sinusoids with a range of amplitudes and frequencies. We vary lens characteristics by varying the Rayleigh number and Mass flux ratio of saline and fresh water, as these dominantly influence the thickness of thin lenses and their mixing zone. Numerical results show a linear relation between the normalised lens volume and the main lens and recharge characteristics, enabling an empirical approximation of the variation of lens thickness. Increase of the recharge amplitude causes increase and the increase of recharge frequency causes a decrease in the variation of lens thickness. The average lens thickness is not significantly influenced by these variations in recharge, contrary to the mixing zone thickness. The mixing zone thickness is compared to that of a Fickian mixing regime. A simple relation between the travelled distance of the centre of the mixing zone position due to variations in recharge and the mixing zone thickness is shown to be valid for both a sinusoidal recharge variation and actual records of daily recharge data. Starting from a step response function, convolution can be used to determine the effect of variable recharge in time. For a sinusoidal curve, we can determine delay of lens movement compared to the recharge curve as well as the lens amplitude, derived from the convolution integral. Together the proposed equations provide us with a first order approximation of lens

  20. Evaluating the Impacts of Grassland Conversions to Experimental Forest on Groundwater Recharge in the Nebraska Sand Hills

    Science.gov (United States)

    Adane, Zablon A.

    The Nebraska Sand Hills grasslands provide the greatest groundwater recharge rates in the High Plains Aquifer. However, the grasslands and their ecological services have become vulnerable to land use change and degradation. This study used a series of field data to investigate the effects of grassland conversions to forest on recharge rates in a century-old experimental forest in the Sand Hills. The results show that the impact of grassland conversion on recharge was dependent on the species and plantation density. Estimated recharge rates beneath the dense plantations represent reductions of 86-94% relative to the native grassland. Results of 1H Nuclear Magnetic Resonance spectral analysis suggested that the surface soil organic carbon beneath pine plantations also contain up to 3 times the ratio of hydrophobic components than the native grasslands and may alter the soil hydraulic properties. This investigation further uncovered a previously overlooked feedback between the effect of soil organic carbon chemical shift generated by the ponderosa pine needle litter decomposition; namely that the alteration may have a link to reduced groundwater recharge rates. Thus, a global optimizer algorithm was used to estimate the effective soil hydraulic parameters from monthly soil moisture contents and recharge rates were then estimated through HYDRUS 1-D numerical modeling for grassland and pine forest soils. The impact of grassland conversion to pine was an overall reduction of groundwater recharge by nearly 100%. These outcomes highlight the significance of the grasslands for recharge, in the Sand Hills and the sustainability of the High Plains Aquifer.

  1. Effects of Climate Change on Groundwater Recharge (Case Study: Sefid Dasht Plain

    Directory of Open Access Journals (Sweden)

    samin ansari

    2017-02-01

    Full Text Available Introduction: Nowadays, the issue of climate change and its related problems are fundamental crisis in water resource management. On the other hand, considering that groundwater is the most important water resources, determination of the effects of climate change on groundwater and estimation the amount of their recharge will be necessary in the future. Materials and Methods: In this research, to analyze the effects of climate change scenarios on groundwater resources, a case study has been applied to the Sefid Dasht Plain located in Chahar Mahal and Bakhtiari Province in Iran. One of the three Atmospheric-Ocean General Circulation Models (AOGCM which is called HadCM3, under the emission scenarios A2 and B1 is used to predict time series of climate variables of temperature and precipitation in the future. In order to downscale the data for producing the regional climate scenarios, LARS-WG model has been applied. Also, IHACRES model is calibrated and used for simulation of rainfall - runoff with monthly temperature, precipitation and runoff data. The predicted runoff and precipitation production in future have been considered as recharge parameters in the ground water model and the effects of climate change scenarios on the ground water table has been studied. To simulate the aquifer, GMS software has been used. GMS model is calibrated in both steady and unsteady state for one year available data and verification model has been performed by using the calibration parameters for four years. Results and Discussion: Results of T- test shows that LARS-WG model was able to simulate precipitation and temperature selected station appropriately. Calibration of IHACRES model indicated the best performance with τw=6 و f=7.7 and the results shows that IHACRES model simulated minimum amount of runoff appropriately. Although it didn’t simulate the maximum amount of runoff accurately, but its performance and Nash coefficient is acceptable. Results indicate

  2. Modeling hydrology, groundwater recharge and non-point nitrate loadings in the Himalayan Upper Yamuna basin

    International Nuclear Information System (INIS)

    Narula, Kapil K.; Gosain, A.K.

    2013-01-01

    The mountainous Himalayan watersheds are important hydrologic systems responsible for much of the water supply in the Indian sub-continent. These watersheds are increasingly facing anthropogenic and climate-related pressures that impact spatial and temporal distribution of water availability. This study evaluates temporal and spatial distribution of water availability including groundwater recharge and quality (non-point nitrate loadings) for a Himalayan watershed, namely, the Upper Yamuna watershed (part of the Ganga River basin). The watershed has an area of 11 600 km 2 with elevation ranging from 6300 to 600 m above mean sea level. Soil and Water Assessment Tool (SWAT), a physically-based, time-continuous model, has been used to simulate the land phase of the hydrological cycle, to obtain streamflows, groundwater recharge, and nitrate (NO 3 ) load distributions in various components of runoff. The hydrological SWAT model is integrated with the MODular finite difference groundwater FLOW model (MODFLOW), and Modular 3-Dimensional Multi-Species Transport model (MT3DMS), to obtain groundwater flow and NO 3 transport. Validation of various modules of this integrated model has been done for sub-basins of the Upper Yamuna watershed. Results on surface runoff and groundwater levels obtained as outputs from simulation show a good comparison with the observed streamflows and groundwater levels (Nash–Sutcliffe and R 2 correlations greater than + 0.7). Nitrate loading obtained after nitrification, denitrification, and NO 3 removal from unsaturated and shallow aquifer zones is combined with groundwater recharge. Results for nitrate modeling in groundwater aquifers are compared with observed NO 3 concentration and are found to be in good agreement. The study further evaluates the sensitivity of water availability to climate change. Simulations have been made with the weather inputs of climate change scenarios of A2, B2, and A1B for end of the century. Water yield estimates

  3. Modeling hydrology, groundwater recharge and non-point nitrate loadings in the Himalayan Upper Yamuna basin

    Energy Technology Data Exchange (ETDEWEB)

    Narula, Kapil K., E-mail: kkn2104@columbia.edu [Columbia Water Center (India Office), Columbia University, New Delhi 110 016 (India); Gosain, A.K. [Department of Civil Engineering, Indian Institute of Technology (IIT) Delhi, Hauz Khas, New Delhi 110 016 (India)

    2013-12-01

    The mountainous Himalayan watersheds are important hydrologic systems responsible for much of the water supply in the Indian sub-continent. These watersheds are increasingly facing anthropogenic and climate-related pressures that impact spatial and temporal distribution of water availability. This study evaluates temporal and spatial distribution of water availability including groundwater recharge and quality (non-point nitrate loadings) for a Himalayan watershed, namely, the Upper Yamuna watershed (part of the Ganga River basin). The watershed has an area of 11 600 km{sup 2} with elevation ranging from 6300 to 600 m above mean sea level. Soil and Water Assessment Tool (SWAT), a physically-based, time-continuous model, has been used to simulate the land phase of the hydrological cycle, to obtain streamflows, groundwater recharge, and nitrate (NO{sub 3}) load distributions in various components of runoff. The hydrological SWAT model is integrated with the MODular finite difference groundwater FLOW model (MODFLOW), and Modular 3-Dimensional Multi-Species Transport model (MT3DMS), to obtain groundwater flow and NO{sub 3} transport. Validation of various modules of this integrated model has been done for sub-basins of the Upper Yamuna watershed. Results on surface runoff and groundwater levels obtained as outputs from simulation show a good comparison with the observed streamflows and groundwater levels (Nash–Sutcliffe and R{sup 2} correlations greater than + 0.7). Nitrate loading obtained after nitrification, denitrification, and NO{sub 3} removal from unsaturated and shallow aquifer zones is combined with groundwater recharge. Results for nitrate modeling in groundwater aquifers are compared with observed NO{sub 3} concentration and are found to be in good agreement. The study further evaluates the sensitivity of water availability to climate change. Simulations have been made with the weather inputs of climate change scenarios of A2, B2, and A1B for end of the

  4. Isotopic study of the effect of Tarbela reservoir on the groundwater system in the downstream areas

    International Nuclear Information System (INIS)

    Sajjad, M.I.; Tasneem, M.A.; Hussain, S.D.; Khan, I.H.; Ali, M.; Latif, Z.

    1994-04-01

    Isotopic studies were carried out on the right side of river Indus, downstream of Tarbela dam to study the effect of Tarbela Reservoir on the groundwater system. The main objectives of the study were to determine the hydraulic connection, if any, between the Tarbela Lake and the groundwater appearing in the ponds near Gadon Amazai, see the effect of Tarbela dam on the groundwater system in the downstream areas, compute the relative contribution of different recharge sources towards groundwater system and to estimate residence time of groundwater in the area. Isotopic data reveals that the ponds near Gadoon Amazai area are being recharged by local rains and there is no contribution of Tarbela lake. The area around Gadoon Amazai, Topi and Kalabat is solely recharged by local rains while the area around Swabi, Zaida and Lahor has mixed recharge with major contribution from local canal system. Tritium data suggests that the residence time of groundwater in the study area varies from a few years to 30 years. Te groundwater in the area has low dissolved salt contents and is, generally, of good quality. (author) 19 figs

  5. Applying limited data to estimate groundwater recharge in the Bida Basin, central Nigeria

    International Nuclear Information System (INIS)

    Shekwolo, P. D.

    2000-01-01

    Three river catchment basins in central Nigeria were studied to determine the amount to recharge to groundwater reservoir, using different techniques. The techniques include groundwater rise or specific yield, flownet, baseflow separation and chloride mass balance (CMB). Though results from the various methods vary within some limits, there is a fairly good agreement, particularly in the recharge percentages. Groundwater rise technique gave a value of about 53 mm/yr and 56 mm/yr in Gboko and Eku catchments respectively, which represents about 5% of the annual precipitation in Eku catchment. CMB method yielded 5% in Gboko, 4% in Eku and 7% in Kaduna catchment of annual precipitation. On the average, annual recharge in the entire basins falls within the range of 50 mm to 100 mm, which constitute about 5 - 10% of annual precipitation. All the methods can be considered complementary to each other, in the sense that sone salient hydrologic parameters that are not considered or emphasised in one technique appear in the other. The chloride mass and baseflow separation methods can be said to be fair result - yielding approach, because of the relatively good data acquisition in spite of the limitations of the method and their relevance to prevailing local conditions. Multi - technique approach is the best in recharge estimation because it allows an independent check to be made on the results. The value of hydrologic ration falls within the range of 0.45 to 0.8 and the study area has been classified into semi - humid and semi - arid climatic zones, on the basis of the hydrologic model

  6. Recharge and discharge of near-surface groundwater in Forsmark. Comparison of classification methods

    International Nuclear Information System (INIS)

    Werner, Kent; Johansson, Per-Olof; Brydsten, Lars; Bosson, Emma; Berglund, Sten

    2007-03-01

    This report presents and compares data and models for identification of near-surface groundwater recharge and discharge (RD) areas in Forsmark. The general principles of groundwater recharge and discharge are demonstrated and applied to interpret hydrological and hydrogeological observations made in the Forsmark area. 'Continuous' RD classification methods considered in the study include topographical modelling, map overlays, and hydrological-hydrogeological flow modelling. 'Discrete' (point) methods include field-based and hydrochemistry-based RD classifications of groundwater monitoring well locations. The topographical RD modelling uses the digital elevation model as the only input. The map overlays use background maps of Quaternary deposits, soils, and ground- and field layers of the vegetation/land use map. Further, the hydrological-hydrogeological modelling is performed using the MIKE SHE-MIKE 11 software packages, taking into account e.g. topography, meteorology, hydrogeology, and geometry of watercourses and lakes. The best between-model agreement is found for the topography-based model and the MIKE SHE-MIKE 11 model. The agreement between the topographical model and the map overlays is less good. The agreement between the map overlays on the one hand, and the MIKE SHE and field-based RD classifications on the other, is thought to be less good, as inferred from the comparison made with the topography-based model. However, much improvement of the map overlays can likely be obtained, e.g. by using 'weights' and calibration (such exercises were outside the scope of the present study). For field-classified 'recharge wells', there is a good agreement to the hydrochemistry-based (Piper plot) well classification, but less good for the field-classified 'discharge wells'. In addition, the concentration of the age-dating parameter tritium shows low variability among recharge wells, but a large spread among discharge wells. The usefulness of hydrochemistry-based RD

  7. Recharge beneath low-impact design rain gardens and the influence of El Niño Southern Oscillation on urban, coastal groundwater resources

    Science.gov (United States)

    Newcomer, M. E.; Gurdak, J. J.

    2011-12-01

    Groundwater resources in urban, coastal environments are highly vulnerable to increased human pressures and climate variability. Impervious surfaces, such as buildings, roads, and parking lots prevent infiltration, reduce recharge to underlying aquifers, and increase contaminants in surface runoff that often overflow sewage systems. To mitigate these effects, cities worldwide are adopting low impact design (LID) approaches that direct runoff into natural vegetated systems, such as rain gardens that reduce, filter, and slow stormwater runoff, and are hypothesized to increase infiltration and recharge rates to aquifers. The effects of LID on recharge rates and quality is unknown, particularly during intense precipitation events for cities along the Pacific coast in response to interannual variability of the El Niño Southern Oscillation (ENSO). Using vadose zone monitoring sensors and instruments, I collected and monitored soil, hydraulic, and geochemical data to quantify the rates and quality of infiltration and recharge to the California Coastal aquifer system beneath a LID rain garden and traditional turf-lawn setting in San Francisco, CA. The data were used to calibrate a HYDRUS-3D model to simulate recharge rates under historical and future variability of ENSO. Understanding these processes has important implications for managing groundwater resources in urban, coastal environments.

  8. Characterizing Field Biodegradation of N-nitrosodimethylamine (NDMA) in Groundwater with Active Reclaimed Water Recharge

    Science.gov (United States)

    McCraven, S.; Zhou, Q.; Garcia, J.; Gasca, M.; Johnson, T.

    2007-12-01

    N-Nitrosodimethylamine (NDMA) is an emerging contaminant in groundwater, because of its aqueous miscibility, exceptional animal toxicity, and human carcinogenicity. NDMA detections in groundwater have been tracked to either decomposition of unsymmetrical dimethylhydrazine (UDMH) used in rocket fuel facilities or chlorine disinfection in wastewater reclamation plants. Laboratory experiments on both unsaturated and saturated soil samples have demonstrated that NDMA can be biodegraded by microbial activity, under both aerobic and anaerobic conditions. However, very limited direct evidence for its biodegradation has been found from the field in saturated groundwater. Our research aimed to evaluate photolysis and biodegradation of NDMA occurring along the full travel path - from wastewater reclamation plant effluent, through rivers and spreading grounds, to groundwater. For this evaluation, we established an extensive monitoring network to characterize NDMA concentrations at effluent discharge points, surface water stations, and groundwater monitoring and production wells, during the operation of the Montebello Forebay Groundwater Recharge facilities in Los Angeles County, California. Field monitoring for NDMA has been conducted for more than six years, including 32 months of relatively lower NDMA concentrations in effluent, 43 months of elevated NDMA effluent concentrations, and 7 months with significantly reduced NDMA effluent concentrations. The NDMA effluent concentration increase and significant concentration decrease were caused by changes in treatment processes. The NDMA sampling data imply that significant biodegradation occurred in groundwater, accounting for a 90% mass reduction of NDMA over the six-year monitoring period. In addition, the occurrence of a discrete well monitored effluent release during the study period allowed critical analysis of the fate of NDMA in a well- characterized, localized groundwater flow subsystem. The data indicate that 80% of the

  9. Future irrigation expansion outweigh groundwater recharge gains from climate change in semi-arid India.

    Science.gov (United States)

    Sishodia, Rajendra P; Shukla, Sanjay; Wani, Suhas P; Graham, Wendy D; Jones, James W

    2018-09-01

    Simultaneous effects of future climate and irrigation intensification on surface and groundwater systems are not well understood. Efforts are needed to understand the future groundwater availability and associated surface flows under business-as-usual management to formulate policy changes to improve water sustainability. We combine measurements with integrated modeling (MIKE SHE/MIKE11) to evaluate the effects of future climate (2040-2069), with and without irrigation expansion, on water levels and flows in an agricultural watershed in low-storage crystalline aquifer region of south India. Demand and supply management changes, including improved efficiency of irrigation water as well as energy uses, were evaluated. Increased future rainfall (7-43%, from 5 Global Climate Models) with no further expansion of irrigation wells increased the groundwater recharge (10-55%); however, most of the recharge moved out of watershed as increased baseflow (17-154%) with a small increase in net recharge (+0.2mm/year). When increased rainfall was considered with projected increase in irrigation withdrawals, both hydrologic extremes of well drying and flooding were predicted. A 100-year flow event was predicted to be a 5-year event in the future. If irrigation expansion follows the historical trends, earlier and more frequent well drying, a source of farmers' distress in India, was predicted to worsen in the future despite the recharge gains from increased rainfall. Storage and use of excess flows, improved irrigation efficiency with flood to drip conversion in 25% of irrigated area, and reduced energy subsidy (free electricity for 3.5h compared to 7h/day; $1 billion savings) provided sufficient water savings to support future expansion in irrigated areas while mitigating well drying as well as flooding. Reductions in energy subsidy to fund the implementation of economically desirable (high benefit-cost ratio) demand (drip irrigation) and supply (water capture and storage

  10. U.S. Geological Survey groundwater toolbox, a graphical and mapping interface for analysis of hydrologic data (version 1.0): user guide for estimation of base flow, runoff, and groundwater recharge from streamflow data

    Science.gov (United States)

    Barlow, Paul M.; Cunningham, William L.; Zhai, Tong; Gray, Mark

    2015-01-01

    This report is a user guide for the streamflow-hydrograph analysis methods provided with version 1.0 of the U.S. Geological Survey (USGS) Groundwater Toolbox computer program. These include six hydrograph-separation methods to determine the groundwater-discharge (base-flow) and surface-runoff components of streamflow—the Base-Flow Index (BFI; Standard and Modified), HYSEP (Fixed Interval, Sliding Interval, and Local Minimum), and PART methods—and the RORA recession-curve displacement method and associated RECESS program to estimate groundwater recharge from streamflow data. The Groundwater Toolbox is a customized interface built on the nonproprietary, open source MapWindow geographic information system software. The program provides graphing, mapping, and analysis capabilities in a Microsoft Windows computing environment. In addition to the four hydrograph-analysis methods, the Groundwater Toolbox allows for the retrieval of hydrologic time-series data (streamflow, groundwater levels, and precipitation) from the USGS National Water Information System, downloading of a suite of preprocessed geographic information system coverages and meteorological data from the National Oceanic and Atmospheric Administration National Climatic Data Center, and analysis of data with several preprocessing and postprocessing utilities. With its data retrieval and analysis tools, the Groundwater Toolbox provides methods to estimate many of the components of the water budget for a hydrologic basin, including precipitation; streamflow; base flow; runoff; groundwater recharge; and total, groundwater, and near-surface evapotranspiration.

  11. A new groundwater radiocarbon correction approach accounting for palaeoclimate conditions during recharge and hydrochemical evolution: The Ledo-Paniselian Aquifer, Belgium

    Energy Technology Data Exchange (ETDEWEB)

    Blaser, P.C., E-mail: petra.blaser@petraconsult.com [Petraconsult buero fuer angewandte geologie dipl. geol. petra c. blaser, Bergstrasse 269, CH 8707 Uetikon am See (Switzerland); Coetsiers, M. [Laboratory for Applied Geology and Hydrogeology, Ghent University, B-9000 Ghent (Belgium); Aeschbach-Hertig, W. [Institut fuer Umweltphysik, Universitaet Heidelberg, D-69120 Heidelberg (Germany); Kipfer, R. [Department of Water Resources and Drinking Water, Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Duebendorf (Switzerland)] [Institute of Isotope Geochemistry and Mineral Resources, ETH Zurich, CH-8092 Zurich (Switzerland); Van Camp, M. [Laboratory for Applied Geology and Hydrogeology, Ghent University, B-9000 Ghent (Belgium); Loosli, H.H. [Department of Climate and Environmental Physics, University of Bern, CH 3012 Bern (Switzerland); Walraevens, K. [Laboratory for Applied Geology and Hydrogeology, Ghent University, B-9000 Ghent (Belgium)

    2010-03-15

    The particular objective of the present work is the development of a new radiocarbon correction approach accounting for palaeoclimate conditions at recharge and hydrochemical evolution. Relevant climate conditions at recharge are atmospheric pCO{sub 2} and infiltration temperatures, influencing C isotope concentrations in recharge waters. The new method is applied to the Ledo-Paniselian Aquifer in Belgium. This is a typical freshening aquifer where recharge takes place through the semi-confining cover of the Bartonian Clay. Besides cation exchange which is the major influencing process for the evolution of groundwater chemistry (particularly in the Bartonian Clay), also mixing with the original porewater solution (fossil seawater) occurs in the aquifer. Recharge temperatures were based on noble gas measurements. Potential infiltration water compositions, for a range of possible pCO{sub 2}, temperature and calcite dissolution system conditions, were calculated by means of PHREEQC. Then the sampled groundwaters were modelled starting from these infiltration waters, using the computer code NETPATH and considering a wide range of geochemical processes. Fitting models were selected on the basis of correspondence of calculated {delta}{sup 13}C with measured {delta}{sup 13}C. The {sup 14}C modelling resulted in residence times ranging from Holocene to Pleistocene (few hundred years to over 40 ka) and yielded consistent results within the uncertainty estimation. Comparison was made with the {delta}{sup 13}C and Fontes and Garnier correction models, that do not take climate conditions at recharge into account. To date these are considered as the most representative process-oriented existing models, yet differences in calculated residence times of mostly several thousands of years (up to 19 ka) are revealed with the newly calculated ages being mostly (though not always) younger. Not accounting for climate conditions at recharge (pCO{sub 2} and temperature) is thus producing

  12. Groundwater recharge - climatic and vegetation induced variations. Simulations in the Emaan and Aespoe areas in southern Sweden

    International Nuclear Information System (INIS)

    Losjoe, K.; Johansson, Barbro; Bringfelt, B.; Oleskog, I.; Bergstroem, S.

    1999-01-01

    Climate change and man-made interference will cause an impact on runoff and groundwater recharge in the future. With the aim to give a conception of seasonal variations and the magnitude of the differences, the HBV model has been used as a tool for simulating five climate alternatives in two areas of south-east Sweden. The climate alternatives include both increased and decreased temperature and precipitation. These are not predictions of a future climate change, and should only be regarded as examples. The purpose has been to exemplify a conceivable magnitude of change during temperate/boreal conditions. It has not been within the scope of this report to evaluate the most probable climate change scenarios. The impacts of different climate scenarios on the total groundwater recharge and the deep groundwater recharge have been calculated as long-term mean values and are presented in comparison with model-simulated values with an actual (recorded) climate sequence. The results show great differences between the climate alternatives. An increase in temperature will decrease snow accumulation and increase the evapotranspiration and can totally extinguish the spring snowmelt peak in runoff and groundwater recharge. A decreased temperature, on the contrary, will imply decreased winter runoff and recharge values and an increase in spring and summer values. Evapotranspiration and soil water content play a key role in the runoff and recharge processes. This report makes a review of some literature about work done within the areas of investigation and calculation of evapotranspiration. Research is in progress, not only on formulating future climate scenarios, but also on distinguishing evapotranspiration from different kinds of vegetation. These are complex questions, but vital ones, as a climate change will also affect the vegetation. Until new research results are presented, well-known methods can be used for simulating the effects of logging on runoff and groundwater

  13. Catchment tracers reveal discharge, recharge and sources of groundwater-borne pollutants in a novel lake modelling approach

    Science.gov (United States)

    Kristensen, Emil; Madsen-Østerbye, Mikkel; Massicotte, Philippe; Pedersen, Ole; Markager, Stiig; Kragh, Theis

    2018-02-01

    Groundwater-borne contaminants such as nutrients, dissolved organic carbon (DOC), coloured dissolved organic matter (CDOM) and pesticides can have an impact the biological quality of lakes. The sources of pollutants can, however, be difficult to identify due to high heterogeneity in groundwater flow patterns. This study presents a novel approach for fast hydrological surveys of small groundwater-fed lakes using multiple groundwater-borne tracers. Water samples were collected from the lake and temporary groundwater wells, installed every 50 m within a distance of 5-45 m to the shore, were analysed for tracer concentrations of CDOM, DOC, total dissolved nitrogen (TDN, groundwater only), total nitrogen (TN, lake only), total dissolved phosphorus (TDP, groundwater only), total phosphorus (TP, lake only), δ18O / δ16O isotope ratios and fluorescent dissolved organic matter (FDOM) components derived from parallel factor analysis (PARAFAC). The isolation of groundwater recharge areas was based on δ18O measurements and areas with a high groundwater recharge rate were identified using a microbially influenced FDOM component. Groundwater discharge sites and the fractions of water delivered from the individual sites were isolated with the Community Assembly via Trait Selection model (CATS). The CATS model utilized tracer measurements of TDP, TDN, DOC and CDOM from the groundwater samples and related these to the tracer measurements of TN, TP, DOC and CDOM in the lake. A direct comparison between the lake and the inflowing groundwater was possible as degradation rates of the tracers in the lake were taken into account and related to a range of water retention times (WRTs) of the lake (0.25-3.5 years in 0.25-year increments). These estimations showed that WRTs above 2 years required a higher tracer concentration of inflowing water than found in any of the groundwater wells around the lake. From the estimations of inflowing tracer concentration, the CATS model isolated

  14. Estimating Groundwater Mounding in Sloping Aquifers for Managed Aquifer Recharge.

    Science.gov (United States)

    Zlotnik, Vitaly A; Kacimov, Anvar; Al-Maktoumi, Ali

    2017-11-01

    Design of managed aquifer recharge (MAR) for augmentation of groundwater resources often lacks detailed data, and simple diagnostic tools for evaluation of the water table in a broad range of parameters are needed. In many large-scale MAR projects, the effect of a regional aquifer base dip cannot be ignored due to the scale of recharge sources (e.g., wadis, streams, reservoirs). However, Hantush's (1967) solution for a horizontal aquifer base is commonly used. To address sloping aquifers, a new closed-form analytical solution for water table mound accounts for the geometry and orientation of recharge sources at the land surface with respect to the aquifer base dip. The solution, based on the Dupiuit-Forchheimer approximation, Green's function method, and coordinate transformations is convenient for computing. This solution reveals important MAR traits in variance with Hantush's solution: mounding is limited in time and space; elevation of the mound is strongly affected by the dip angle; and the peak of the mound moves over time. These findings have important practical implications for assessment of various MAR scenarios, including waterlogging potential and determining proper rates of recharge. Computations are illustrated for several characteristic MAR settings. © 2017, National Ground Water Association.

  15. Groundwater recharge, circulation and geochemical evolution in the source region of the Blue Nile River, Ethiopia

    International Nuclear Information System (INIS)

    Kebede, Seifu; Travi, Yves; Alemayehu, Tamiru; Ayenew, Tenalem

    2005-01-01

    Geochemical and environmental isotope data were used to gain the first regional picture of groundwater recharge, circulation and its hydrochemical evolution in the upper Blue Nile River basin of Ethiopia. Q-mode statistical cluster analysis (HCA) was used to classify water into objective groups and to conduct inverse geochemical modeling among the groups. Two major structurally deformed regions with distinct groundwater circulation and evolution history were identified. These are the Lake Tana Graben (LTG) and the Yerer Tullu Wellel Volcanic Lineament Zone (YTVL). Silicate hydrolysis accompanied by CO 2 influx from deeper sources plays a major role in groundwater chemical evolution of the high TDS Na-HCO 3 type thermal groundwaters of these two regions. In the basaltic plateau outside these two zones, groundwater recharge takes place rapidly through fractured basalts, groundwater flow paths are short and they are characterized by low TDS and are Ca-Mg-HCO 3 type waters. Despite the high altitude (mean altitude ∼2500 masl) and the relatively low mean annual air temperature (18 deg. C) of the region compared to Sahelian Africa, there is no commensurate depletion in δ 18 O compositions of groundwaters of the Ethiopian Plateau. Generally the highland areas north and east of the basin are characterized by relatively depleted δ 18 O groundwaters. Altitudinal depletion of δ 18 O is 0.1%o/100 m. The meteoric waters of the Blue Nile River basin have higher d-excess compared to the meteoric waters of the Ethiopian Rift and that of its White Nile sister basin which emerges from the equatorial lakes region. The geochemically evolved groundwaters of the YTVL and LTG are relatively isotopically depleted when compared to the present day meteoric waters reflecting recharge under colder climate and their high altitude

  16. Groundwater recharge, circulation and geochemical evolution in the source region of the Blue Nile River, Ethiopia

    Energy Technology Data Exchange (ETDEWEB)

    Kebede, Seifu [Laboratory of Hydrogeology, University of Avignon, 33 Rue Louis Pasteur, 84000 Avignon (France) and Department of Geology and Geophysics, Addis Ababa University, P.O. Box 1176, Addis Ababa (Ethiopia)]. E-mail: seifu.kebede@univ-avignon.fr; Travi, Yves [Laboratory of Hydrogeology, University of Avignon, 33 Rue Louis Pasteur, 84000 Avignon (France); Alemayehu, Tamiru [Department of Geology and Geophysics, Addis Ababa University, P.O. Box 1176, Addis Ababa (Ethiopia); Ayenew, Tenalem [Department of Geology and Geophysics, Addis Ababa University, P.O. Box 1176, Addis Ababa (Ethiopia)

    2005-09-15

    Geochemical and environmental isotope data were used to gain the first regional picture of groundwater recharge, circulation and its hydrochemical evolution in the upper Blue Nile River basin of Ethiopia. Q-mode statistical cluster analysis (HCA) was used to classify water into objective groups and to conduct inverse geochemical modeling among the groups. Two major structurally deformed regions with distinct groundwater circulation and evolution history were identified. These are the Lake Tana Graben (LTG) and the Yerer Tullu Wellel Volcanic Lineament Zone (YTVL). Silicate hydrolysis accompanied by CO{sub 2} influx from deeper sources plays a major role in groundwater chemical evolution of the high TDS Na-HCO {sub 3} type thermal groundwaters of these two regions. In the basaltic plateau outside these two zones, groundwater recharge takes place rapidly through fractured basalts, groundwater flow paths are short and they are characterized by low TDS and are Ca-Mg-HCO {sub 3} type waters. Despite the high altitude (mean altitude {approx}2500 masl) and the relatively low mean annual air temperature (18 deg. C) of the region compared to Sahelian Africa, there is no commensurate depletion in {delta} {sup 18}O compositions of groundwaters of the Ethiopian Plateau. Generally the highland areas north and east of the basin are characterized by relatively depleted {delta} {sup 18}O groundwaters. Altitudinal depletion of {delta} {sup 18}O is 0.1%o/100 m. The meteoric waters of the Blue Nile River basin have higher d-excess compared to the meteoric waters of the Ethiopian Rift and that of its White Nile sister basin which emerges from the equatorial lakes region. The geochemically evolved groundwaters of the YTVL and LTG are relatively isotopically depleted when compared to the present day meteoric waters reflecting recharge under colder climate and their high altitude.

  17. Potential Groundwater Recharge and the Effects of Soil Heterogeneity on Flow at Two Radioactive Waste Management Sites at the Nevada Test Site

    International Nuclear Information System (INIS)

    Yucel, V.; Levitt, D. G.

    2001-01-01

    Two low-level Radioactive Waste Management Sites (RWMSs), consisting of shallow land burial disposal units at the Nevada Test Site (NTS), are managed by Bechtel Nevada for the U.S. Department of Energy, National Nuclear Security Administration. The NTS has an arid climate with annual average precipitation of about 17 cm at the Area 3 RWMS and about 13 cm at the Area 5 RWMS. The vadose zone is about 490 m thick at the Area 3 RWMS, and about 235 m thick at the Area 5 RWMS. Numerous studies indicate that under current climatic conditions, there is generally no groundwater recharge at these sites. Groundwater recharge may occur at isolated locations surrounding the RWMSs, such as in large drainage washes. However, groundwater recharge scenarios (and radionuclide transport) at the RWMSs are modeled in support of Performance Assessment (PA) documents required for operation of each RWMS. Recharge scenarios include conditions of massive subsidence and flooding, and recharge resulting from deep infiltration through bare-soil waste covers. This paper summarizes the groundwater recharge scenarios and travel time estimates that have been conducted in support of the PAs, and examines the effects of soil hydraulic property heterogeneity on flow

  18. Recharge and discharge of near-surface groundwater in Forsmark. Comparison of classification methods

    Energy Technology Data Exchange (ETDEWEB)

    Werner, Kent [Golder Associates AB, Uppsala (Sweden); Johansson, Per-Olof [Artesia Grundvattenkonsult AB, Taeby (Sweden); Brydsten, Lars [Umeaa University, Dept. of Ecology and Environmental Science (Sweden); Bosson, Emma; Berglund, Sten [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

    2007-03-15

    This report presents and compares data and models for identification of near-surface groundwater recharge and discharge (RD) areas in Forsmark. The general principles of groundwater recharge and discharge are demonstrated and applied to interpret hydrological and hydrogeological observations made in the Forsmark area. 'Continuous' RD classification methods considered in the study include topographical modelling, map overlays, and hydrological-hydrogeological flow modelling. 'Discrete' (point) methods include field-based and hydrochemistry-based RD classifications of groundwater monitoring well locations. The topographical RD modelling uses the digital elevation model as the only input. The map overlays use background maps of Quaternary deposits, soils, and ground- and field layers of the vegetation/land use map. Further, the hydrological-hydrogeological modelling is performed using the MIKE SHE-MIKE 11 software packages, taking into account e.g. topography, meteorology, hydrogeology, and geometry of watercourses and lakes. The best between-model agreement is found for the topography-based model and the MIKE SHE-MIKE 11 model. The agreement between the topographical model and the map overlays is less good. The agreement between the map overlays on the one hand, and the MIKE SHE and field-based RD classifications on the other, is thought to be less good, as inferred from the comparison made with the topography-based model. However, much improvement of the map overlays can likely be obtained, e.g. by using 'weights' and calibration (such exercises were outside the scope of the present study). For field-classified 'recharge wells', there is a good agreement to the hydrochemistry-based (Piper plot) well classification, but less good for the field-classified 'discharge wells'. In addition, the concentration of the age-dating parameter tritium shows low variability among recharge wells, but a large spread among discharge

  19. Estimation of groundwater recharge using the chloride mass-balance method, Pingtung Plain, Taiwan

    Science.gov (United States)

    Ting, Cheh-Shyh; Kerh, Tienfuan; Liao, Chiu-Jung

    Due to rapid economic growth in the Pingtung Plain of Taiwan, the use of groundwater resources has changed dramatically. Over-pumping of the groundwater reservoir, which lowers hydraulic heads in the aquifers, is not only affecting the coastal area negatively but has serious consequences for agriculture throughout the plain. In order to determine the safe yield of the aquifer underlying the plain, a reliable estimate of groundwater recharge is desirable. In the present study, for the first time, the chloride mass-balance method is adopted to estimate groundwater recharge in the plain. Four sites in the central part were chosen to facilitate the estimations using the ion-chromatograph and Thiessen polygon-weighting methods. Based on the measured and calculated results, in all sites, including the mountain and river boundaries, recharge to the groundwater is probably 15% of the annual rainfall, excluding recharge from additional irrigation water. This information can improve the accuracy of future groundwater-simulation and management models in the plain. Résumé Du fait de la croissance économique rapide de la plaine de Pingtung à Taiwan, l'utilisation des ressources en eau souterraine s'est considérablement modifié. La surexploitation des aquifères, qui a abaissé le niveau des nappes, n'affecte pas seulement la région côtière, mais a de sérieuses répercutions sur l'agriculture dans toute la plaine. Afin de déterminer les ressources renouvelables de l'aquifère sous la plaine, une estimation précise de la recharge de la nappe est nécessaire. Dans cette étude, le taux de recharge de la nappe a d'abord été estimé au moyen d'un bilan de matière de chlorure. Quatre sites de la partie centrale ont été sélectionnés pour réaliser ces estimations, à l'aide d'un chromatographe ionique et de la méthode des polygones de Thiessen. A partir des résultats mesurés et calculés, à chaque site, et en prenant comme limites les montagnes et les rivi

  20. Estimation of the groundwater recharge in laterita using the artificial tritium method

    International Nuclear Information System (INIS)

    Castro Rubio Poli, D. de; Kimmelman e Silva, A.A.; Pfisterer, U.

    1990-01-01

    An estimation of the groundwater recharge was made, for the first time, in laterita, which is a alteration of dunite. This work was carried out at the city of Cajati-Jacupiranga, situated in the Ribeira Valley, state of Sao Paulo. The moisture migration in unsaturated zones was analized using water tagget with artificial tritium. In the place studied, an annual recharge of 1070mm was estimated. This value corresponds to 65% of local precipitation (1650 mm/year). The difference can be considered as a loss through evaporation, evapotranspiration and run off. (author) [pt

  1. Agricultural Recharge Practices for Managing Nitrate in Regional Groundwater: Time-Resolution Assessment of Numerical Modeling Approach

    Science.gov (United States)

    Bastani, M.; Harter, T.

    2017-12-01

    Intentional recharge practices in irrigated landscapes are promising options to control and remediate groundwater quality degradation with respect to nitrate. To better understand the effect of these practices, a fully 3D transient heterogeneous transport model simulation is developed using MODFLOW and MT3D. The model is developed for a long-term study of nitrate improvements in an alluvial groundwater basin in Eastern San Joaquin Valley, CA. Different scenarios of agricultural recharge strategies including crop type change and winter flood flows are investigated. Transient simulations with high spatio-temporal resolutions are performed. We then consider upscaling strategies that would allow us to simplify the modeling process such that it can be applied at a very large basin-scale (1000s of square kilometers) for scenario analysis. We specifically consider upscaling of time-variant boundary conditions (both internal and external) that have significant influence on calculation cost of the model. We compare monthly transient stresses to upscaled annual and further upscaled average steady-state stresses on nitrate transport in groundwater under recharge scenarios.

  2. Impact of surface water recharge on the design of a groundwater monitoring system for the Radioactive Waste Management Complex, Idaho National Engineering Laboratory

    International Nuclear Information System (INIS)

    Wood, T.R.

    1990-01-01

    Recent hydrogeologic studies have been initiated to characterize the hydrogeologic conditions at the Radioactive Waste Management Complex (RWMC) at the Idaho National Engineering Laboratory (INEL). Measured water levels in wells penetrating the Snake River Plain aquifer near the RWMC and the corresponding direction of flow show change over time. This change is related to water table mounding caused by recharge from excess water diverted from the Big Lost River for flood protection during high flows. Water levels in most wells near the RWMC rise on the order of 10 ft (3 m) in response to recharge, with water in one well rising over 60 ft (18 m). Recharge changes the normal south-southwest direction of flow to the east. Design of the proposed groundwater monitoring network for the RWMC must account for the variable directions of groundwater flow. 11 refs., 9 figs., 2 tabs

  3. The impacts of a linear wastewater reservoir on groundwater recharge and geochemical evolution in a semi-arid area of the Lake Baiyangdian watershed, North China Plain

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shiqin [Faculty of Horticulture, Chiba University, Matsudo-City 271-8510 (Japan); Tang, Changyuan, E-mail: cytang@faculty.chiba-u.jp [Faculty of Horticulture, Chiba University, Matsudo-City 271-8510 (Japan); Song, Xianfang [Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China); Wang, Qinxue [National Institute for Environmental Studies, Tsukuba 305-8506 (Japan); Zhang, Yinghua [Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China); Yuan, Ruiqiang [College of Environment and Resources, Shanxi University (China)

    2014-06-01

    Sewage leakage has become an important source of groundwater recharge in urban areas. Large linear wastewater ponds that lack anti-seepage measures can act as river channels that cause the deterioration of groundwater quality. This study investigated the groundwater recharge by leakage of the Tanghe Wastewater Reservoir, which is the largest industrial wastewater channel on the North China Plain. Additionally, water quality evolution was investigated using a combination of multivariate statistical methods, multi-tracers and geochemical methods. Stable isotopes of hydrogen and oxygen indicated high levels of wastewater evaporation. Based on the assumption that the wastewater was under an open system and fully mixed, an evaporation model was established to estimate the evaporation of the wastewater based on isotope enrichments of the Rayleigh distillation theory using the average isotope values for dry and rainy seasons. Using an average evaporation loss of 26.5% for the input wastewater, the estimated recharge fraction of wastewater leakage and irrigation was 73.5% of the total input of wastewater. The lateral regional groundwater inflow was considered to be another recharge source. Combing the two end-members mix model and cluster analysis revealed that the mixture percentage of the wastewater decreased from the Highly Affected Zone (76%) to the Transition Zone (5%). Ion exchange and redox reaction were the dominant geochemical processes when wastewater entered the aquifer. Carbonate precipitation was also a major process affecting evolution of groundwater quality along groundwater flow paths. - Highlights: • An unlined wastewater reservoir caused the deterioration of groundwater quality. • An evaporation fraction was estimated by Rayleigh distillation theory of isotopes. • 73.5% of wastewater recharge to groundwater by leakage and irrigation infiltration. • The region influenced by wastewater was divided into four subzones. • Mixing, ion exchange, and

  4. Recharge estimation in semi-arid karst catchments: Central West Bank, Palestine

    Science.gov (United States)

    Jebreen, Hassan; Wohnlich, Stefan; Wisotzky, Frank; Banning, Andre; Niedermayr, Andrea; Ghanem, Marwan

    2018-03-01

    Knowledge of groundwater recharge constitutes a valuable tool for sustainable management in karst systems. In this respect, a quantitative evaluation of groundwater recharge can be considered a pre-requisite for the optimal operation of groundwater resources systems, particular for semi-arid areas. This paper demonstrates the processes affecting recharge in Palestine aquifers. The Central Western Catchment is one of the main water supply sources in the West Bank. Quantification of potential recharge rates are estimated using chloride mass balance (CMB) and empirical recharge equations over the catchment. The results showing the spatialized recharge rate, which ranges from 111-216 mm/year, representing 19-37% of the long-term mean annual rainfall. Using Water Balance models and climatological data (e. g. solar radiation, monthly temperature, average monthly relative humidity and precipitation), actual evapotranspiration (AET) is estimated. The mean annual actual evapotranspiration was about 66-70% of precipitation.

  5. Groundwater recharge in the Kolokani-Nara region in Mali

    International Nuclear Information System (INIS)

    Dincer, T.; Dray, M.; Zuppi, G.M.; Guerre, A.; Tazioli, G.S.; Traore, S.

    1984-01-01

    The area studied is part of the Nara, Kolokani, Banamba and Koulikoro regions and lies between the Mauritanian frontier and Bamako. It is a Sahel zone devoid of active surface hydrography, the annual rainfall varying between 1000 mm in the south and 400 mm in the north. The altitude decreases from 600 m to 250 m from the Mandingues Plateaux to the Nara plain. The Nara area consists of a basin filled with Cambrian schists containing seams of dolomitic limestones and sandstones cemented by limestone. The thickness of the series is thought to be about 300-500 m. The area of the Mandingues Plateaux is composed of Lower Cambrian sandstone-schist formations with a thickness of several hundred metres, covered with a crust of weathering. The two formations have aquifers of the same type - they are discontinuous with predominantly fissure-type permeability. The permeable zones in the Cambrian schist aquifers are more discontinuous than those in the Cambrian sandstones and are less developed in depth. The recharge conditions, on the other hand, are quite good on account of the sand cover which allows rapid infiltration of rain water. The Lower Cambrian aquifer is highly heterogeneous but much less discontinuous. The transfer of groundwater takes place at the level of small local sub-basins over short distances. The hydrogeological and hydrogeochemical data point to the existence of recent recharge and mixing with older water. The groundwater renewal rate indicates, in many cases, limited water reserves. Infiltration is associated, in some cases, with storms of greater intensity and, in other cases, also with small sudden showers. Under natural conditions, the infiltrated water is generally used up by evapotranspiration. Under conditions of exploitation, a fraction of this recharge is recovered either almost directly or indirectly by replacement of the water taken from the fissured zones of the substratum. (author)

  6. Implications of using on-farm flood flow capture to recharge groundwater and mitigate flood risks along the Kings River, CA.

    Science.gov (United States)

    Bachand, Philip A M; Roy, Sujoy B; Choperena, Joe; Cameron, Don; Horwath, William R

    2014-12-02

    The agriculturally productive San Joaquin Valley faces two severe hydrologic issues: persistent groundwater overdraft and flooding risks. Capturing flood flows for groundwater recharge could help address both of these issues, yet flood flow frequency, duration, and magnitude vary greatly as upstream reservoir releases are affected by snowpack, precipitation type, reservoir volume, and flood risks. This variability makes dedicated, engineered recharge approaches expensive. Our work evaluates leveraging private farmlands in the Kings River Basin to capture flood flows for direct and in lieu recharge, calculates on-farm infiltration rates, assesses logistics, and considers potential water quality issues. The Natural Resources Conservation Service (NRCS) soil series suggested that a cementing layer would hinder recharge. The standard practice of deep ripping fractured the layer, resulting in infiltration rates averaging 2.5 in d(-1) (6 cm d(-1)) throughout the farm. Based on these rates 10 acres are needed to infiltrate 1 cfs (100 m(3) h(-1)) of flood flows. Our conceptual model predicts that salinity and nitrate pulses flush initially to the groundwater but that groundwater quality improves in the long term due to pristine flood flows low in salts or nitrate. Flood flow capture, when integrated with irrigation, is more cost-effective than groundwater pumping.

  7. Evaluation of artificial groundwater recharge effects with MIKE-SHE: a case study.

    Science.gov (United States)

    Leal, M.; Martínez-García, I.; Carreño, F.; de Bustamante, I.; Lillo, J.

    2012-04-01

    In many areas where the technical and financial resources are limited, the treatment and disposal of wastewater comprise a problem. With increasing frequency, the wastewater reuse is considered as another alternative for water management alternative. In this way, the wastewater is converted into an added value resource. Treated wastewater infiltration into the soil could be a viable tertiary treatment, especially for small communities where the availability of land is not a problem and the wastewater has not industrial waste contribution and is highly biodegradable. The Experimental Plant of Carrión de los Céspedes (Seville, Spain) develops non-conventional wastewater treatments for small villages. Currently, a project regarding wastewater reutilization for aquifer recharge through a horizontal permeable reactive barrier and a subsequent soil infiltration is being carried out. One of the aspects to be evaluated within this context is the impact on aquifer. Consequently, the main goal of the present study is to assess the effects on the water flow derived from the future recharge activities by using the MIKE-SHE hydrological code. The unsaturated and saturated zones have been integrated in the model, which requires geological, land use, topography, piezometric head, soil and climate data to build up the model. The obtained results from the model show that with the annual recharge volume contributed by the experimental plant (3 m3 or 0.19 L/s) there is no effect in the groundwater flow. A volume of 400 m3/year (25 L/s) would be required to yield a variation in the piezometric head and therefore, in the groundwater flow i.e. a volume about 100 times larger than the estimated is necessary. To calibrate the model, simulated piezometric head values have been compared to the measured field data at a number of locations. In the calibration, the percent error had to be lower than 15 % at each location. Future works concerning groundwater quality and reactive transport

  8. Mapping potential zones for groundwater recharge and its evaluation in arid environments using a GIS approach: Case study of North Gafsa Basin (Central Tunisia)

    Science.gov (United States)

    Mokadem, Naziha; Boughariou, Emna; Mudarra, Matías; Ben Brahim, Fatma; Andreo, Bartolome; Hamed, Younes; Bouri, Salem

    2018-05-01

    With the progressive evolution of industrial sector, agricultural, urbanization, population and drinking water supply, the water demand continuously increases which necessitates the planning of groundwater recharge particularly in arid and semi-arid regions. This paper gives a comprehensive review of various recharges studies in the North Gafsa basin (South Tunisia). This latter is characterized by a natural groundwater recharge that is deeply affected by the lack of precipitations. The aim of this study is to determine the recharge potential zones and to quantify (or estimate) the rainfall recharge of the shallow aquifers. The mapping of the potential recharge zones was established in North Gafsa basin, using geological and hydrological parameters such as slope, lithology, topography and stream network. Indeed, GIS provide tools to reclassify these input layers to produce the final map of groundwater potential zones of the study area. The final output map reveals two distinct zones representing moderate and low groundwater potential recharge. Recharge estimations were based on the four methods: (1) Chloride Method, (2) ERAS Method, (3) DGRE coefficient and (4) Fersi equations. Therefore, the overall results of the different methods demonstrate that the use of the DGRE method applying on the potential zones is more validated.

  9. Analysis of sensitivity of simulated recharge to selected parameters for seven watersheds modeled using the precipitation-runoff modeling system

    Science.gov (United States)

    Ely, D. Matthew

    2006-01-01

    Recharge is a vital component of the ground-water budget and methods for estimating it range from extremely complex to relatively simple. The most commonly used techniques, however, are limited by the scale of application. One method that can be used to estimate ground-water recharge includes process-based models that compute distributed water budgets on a watershed scale. These models should be evaluated to determine which model parameters are the dominant controls in determining ground-water recharge. Seven existing watershed models from different humid regions of the United States were chosen to analyze the sensitivity of simulated recharge to model parameters. Parameter sensitivities were determined using a nonlinear regression computer program to generate a suite of diagnostic statistics. The statistics identify model parameters that have the greatest effect on simulated ground-water recharge and that compare and contrast the hydrologic system responses to those parameters. Simulated recharge in the Lost River and Big Creek watersheds in Washington State was sensitive to small changes in air temperature. The Hamden watershed model in west-central Minnesota was developed to investigate the relations that wetlands and other landscape features have with runoff processes. Excess soil moisture in the Hamden watershed simulation was preferentially routed to wetlands, instead of to the ground-water system, resulting in little sensitivity of any parameters to recharge. Simulated recharge in the North Fork Pheasant Branch watershed, Wisconsin, demonstrated the greatest sensitivity to parameters related to evapotranspiration. Three watersheds were simulated as part of the Model Parameter Estimation Experiment (MOPEX). Parameter sensitivities for the MOPEX watersheds, Amite River, Louisiana and Mississippi, English River, Iowa, and South Branch Potomac River, West Virginia, were similar and most sensitive to small changes in air temperature and a user-defined flow

  10. Field evidence of biodegradation of N-Nitrosodimethylamine (NDMA) in groundwater with incidental and active recycled water recharge.

    Science.gov (United States)

    Zhou, Quanlin; McCraven, Sally; Garcia, Julio; Gasca, Monica; Johnson, Theodore A; Motzer, William E

    2009-02-01

    Biodegradation of N-Nitrosodimethylamine (NDMA) has been found through laboratory incubation in unsaturated and saturated soil samples under both aerobic and anaerobic conditions. However, direct field evidence of in situ biodegradation in groundwater is very limited. This research aimed to evaluate biodegradation of NDMA in a large-scale groundwater system receiving recycled water as incidental and active recharge. NDMA concentrations in 32 monitoring and production wells with different screen intervals were monitored over a period of seven years. Groundwater monitoring was used to characterize changes in the magnitude and extent of NDMA in groundwater in response to seasonal hydrogeologic conditions and, more importantly, to significant concentration variations in effluent from water reclamation plants (associated with treatment-process changes). Extensive monitoring of NDMA concentrations and flow rates at effluent discharge locations and surface-water stations was also conducted to reasonably estimate mass loading through unlined river reaches to underlying groundwater. Monitoring results indicate that significant biodegradation of NDMA occurred in groundwater, accounting for an estimated 90% mass reduction over the seven-year monitoring period. In addition, a discrete effluent-discharge and groundwater-extraction event was extensively monitored in a well-characterized, localized groundwater subsystem for 626 days. Analysis of the associated NDMA fate and transport in the subsystem indicated that an estimated 80% of the recharged mass was biodegraded. The observed field evidence of NDMA biodegradation is supported by groundwater transport modeling accounting for various dilution mechanisms and first-order decay for biodegradation, and by a previous laboratory study on soil samples collected from the study site [Bradley, P.M., Carr, S.A., Baird, R.B., Chapelle, F.H., 2005. Biodegradation of N-Nitrosodimethylamine in soil from a water reclamation facility

  11. Spatiotemporal variation of the surface water effect on the groundwater recharge in a low-precipitation region: Application of the multi-tracer approach to the Taihang Mountains, North China

    Science.gov (United States)

    Sakakibara, Koichi; Tsujimura, Maki; Song, Xianfang; Zhang, Jie

    2017-02-01

    Groundwater recharge variations in time and space are crucial for effective water management, especially in low-precipitation regions. To determine comprehensive groundwater recharge processes in a catchment with large seasonal hydrological variations, intensive field surveys were conducted in the Wangkuai Reservoir watershed located in the Taihang Mountains, North China, during three different times of the year: beginning of the rainy season (June 2011), mid-rainy season (August 2012), and dry season (November 2012). Oxygen and hydrogen isotope and chemical analyses were conducted on the groundwater, spring water, stream water, and reservoir water of the Wangkuai Reservoir watershed. The results were processed using endmember mixing analysis to determine the amount of contribution of the groundwater recharging processes. Similar isotopic and chemical signatures between the surface water and groundwater in the target area indicate that the surface water in the mountain-plain transitional area and the Wangkuai Reservoir are the principal groundwater recharge sources, which result from the highly permeable geological structure of the target area and perennial large-scale surface water, respectively. Additionally, the widespread and significant effect of the diffuse groundwater recharge on the Wangkuai Reservoir was confirmed with the deuterium (d) excess indicator and the high contribution throughout the year, calculated using endmember mixing analysis. Conversely, the contribution of the stream water to the groundwater recharge in the mountain-plain transitional area clearly decreases from the beginning of the rainy season to the mid-rainy season, whereas that of the precipitation increases. This suggests that the main groundwater recharge source shifts from stream water to episodic/continuous heavy precipitation in the mid-rainy season. In other words, the surface water and precipitation commonly affect the groundwater recharge in the rainy season, whereas the

  12. The evolution of redox conditions and groundwater geochemistry in recharge-discharge environments on the Canadian Shield

    International Nuclear Information System (INIS)

    Gascoyne, M.

    1996-10-01

    Groundwater composition evolves along flow paths from recharge to discharge in response to interactions with bedrock and fracture-filling minerals, and dissolution of soluble (Cl-rich) salts in the rock matrix. The groundwater redox potential changes from oxidizing to reducing conditions due, initially, to rapid consumption of dissolved oxygen by organics in the upper ∼100 m of bedrock and, subsequently, interaction with Fe (II)-containing minerals. Measured Eh values of groundwaters at depth in the granitic Lac du Bonnet batholith indicate that biotite and chlorite control groundwater redox potential. This is supported by other geochemical characteristics such as absence of CH 4 , H 2 S, H 2 , NO 3 , low concentrations of Fe (II), and abundance of SO 4 . Further evidence of evolution of redox conditions is given by variations in U concentration ranging from up to 1000 μg/L in dilute near-surface waters to <1 μg/L in some deep, saline groundwaters. Groundwaters at about 400 m depth in a recharge area on the Lac du Bonnet batholith contain significantly more U than groundwaters further along the flow path or near surface in discharge areas. Uranium concentration is found to be a useful and sensitive indicator of redox conditions. (author)

  13. Climate proxy data as groundwater tracers in regional flow systems

    Science.gov (United States)

    Clark, J. F.; Morrissey, S. K.; Stute, M.

    2008-05-01

    The isotopic and chemical signatures of groundwater reflect local climate conditions. By systematically analyzing groundwater and determining their hydrologic setting, records of past climates can be constructed. Because of their chemistries and relatively uncomplicated source functions, dissolved noble gases have yielded reliable records of continental temperatures for the last 30,000 to 50,000 years. Variations in the stable isotope compositions of groundwater due to long term climate changes have also been documented over these time scales. Because glacial - interglacial climate changes are relatively well known, these climate proxies can be used as "stratigraphic" markers within flow systems and used to distinguish groundwaters that have recharged during the Holocene from those recharged during the last glacial period, important time scales for distinguishing regional and local flow systems in many aquifers. In southern Georgia, the climate proxy tracers were able to identify leakage from surface aquifers into the Upper Floridan aquifer in areas previously thought to be confined. In south Florida, the transition between Holocene and glacial signatures in the Upper Floridan aquifer occurs mid-way between the recharge area and Lake Okeechobee. Down gradient of the lake, the proxies are uniform, indicating recharge during the last glacial period. Furthermore, there is no evidence for leakage from the shallow aquifers into the Upper Floridan. In the Lower Floridan, the climate proxies indicate that the saline water entered the aquifer after sea level rose to its present level.

  14. Groundwater recharge in desert playas: current rates and future effects of climate change

    Science.gov (United States)

    Our results from playas, which are topographic low areas situated in closed-catchments in drylands, indicated that projected climate change in Southwestern USA would have a net positive impact over runon and groundwater recharge beneath playas. Expected increased precipitation variability can cause ...

  15. Estimation of groundwater recharge from the subsurface to the rock mass. A case study of Tono Mine Area, Gifu Prefecture

    International Nuclear Information System (INIS)

    Kobayashi, Koichi; Nakano, Katushi; Koide, Kaoru

    1996-01-01

    The groundwater flow analysis involve the groundwater recharge from the subsurface to the rock mass. According to water balance method, annual groundwater recharge is calculated by the remainder of annual evapotranspirator and river flow from annual precipitation. In this estimation, hydrological and meteorological data observed for 5 years on the watershed in Tono mine area is used. Annual precipitation ranges from 1,000 to 1,900 mm and annual river flow ranges from 400 to 1,300 mm, then river flow depends critically on precipitation. Annual evapotranspiration calculated by Penman method ranges from 400 to 500 mm. It is less fluctuant than annual precipitation. As the result of examination of water balance in subsurface zone estimated, annual ground water recharge ranges from 10 to 200 mm in this watershed. (author)

  16. Groundwater conservation and monitoring activities in the middle Brenta River plain (Veneto Region, Northern Italy: preliminary results about aquifer recharge

    Directory of Open Access Journals (Sweden)

    Andrea Sottani

    2014-09-01

    Full Text Available In the middle Brenta River plain there is a unconfined aquifer that represents an important groundwater resource in Veneto region. In this area the main groundwater recharge factor is related to the stream seepage: the water dispersion from the Brenta river is active with variable intensity from the foothill to the alignment Nove di Bassano - Cartigliano (Province of Vicenza. In order to mitigate the expected groundwater effects, due to future important waterworks withdrawals provided by the regional water resources management plans, an experimental project of Managed Aquifer Recharge has started, by means of the realization of some river transversal ramps. The construction of pilot works, partially completed, were preceded by a specific hydrogeological monitoring program, aimed to the evaluation of the effectiveness of the MAR actions in terms of comparison between pre-and post-operam conditions. Thanks to the development of a site-specific methodology, aimed to the quantification of the artificial infiltration rate, and after some years of monitoring controls of the hydrological and hydrogeological regimes, it is now possible to evaluate the extent and the rate of the recharge effects in groundwater due to ramps realization. The monitoring plan will be continued in the medium-long term. Some innovative approaches, based for example on the use of groundwater temperature measurements as recharge tracer, will help to validate the preliminary results.

  17. Hydrologic conditions, recharge, and baseline water quality of the surficial aquifer system at Jekyll Island, Georgia, 2012-13

    Science.gov (United States)

    Gordon, Debbie W.; Torak, Lynn J.

    2016-03-08

    An increase of groundwater withdrawals from the surficial aquifer system on Jekyll Island, Georgia, prompted an investigation of hydrologic conditions and water quality by the U.S. Geological Survey during October 2012 through December 2013. The study demonstrated the importance of rainfall as the island’s main source of recharge to maintain freshwater resources by replenishing the water table from the effects of hydrologic stresses, primarily evapotranspiration and pumping. Groundwater-flow directions, recharge, and water quality of the water-table zone on the island were investigated by installing 26 shallow wells and three pond staff gages to monitor groundwater levels and water quality in the water-table zone. Climatic data from Brunswick, Georgia, were used to calculate potential maximum recharge to the water-table zone on Jekyll Island. A weather station located on the island provided only precipitation data. Additional meteorological data from the island would enhance potential evapotranspiration estimates for recharge calculations.

  18. Use of stable and radioactive isotopes in the determination of the recharge rate in Djeffara aquifer system southern Tunisia

    International Nuclear Information System (INIS)

    Trabelisi, R.; Zouari, K.

    2012-12-01

    Southern Tunisia is characterized by the presence of several hydrogeological basins, which extend over Tunisian borders. The Djeffara aquifer is one of the most important aquifer systems n this area and contains several interconnected aquifer levels. Stable (δ 2 H, δ 18 O and δ 13 C) and radioactive isotopes (1 4C , 3 H ) have been used to evaluate recharge mechanisms and groundwater residence time in the Djeffara multi-aquifer. Thesis aquifer presents two compartments, the first one ( west of the Medenine fault system) is unconfined with a well defined isotope fingerprint, the second compartment is deeper and confined multi- tracer results show groundwater of different origins, and ages , and that tectonic features control ground water flows. The unconfined part was mostly recharged during the Holocene. The recharge rates of this aquifer, inferred by 1 4C ages, are variable and could reach 3.5 mm/year. However, stable isotope composition and 1 4 'C content of the confined groundwater indicates carrier recharge during late pelistocene cold periods. (Author)

  19. Delineating sources of groundwater recharge in an arsenic-affected Holocene aquifer in Cambodia using stable isotope-based mixing models

    Science.gov (United States)

    Richards, Laura A.; Magnone, Daniel; Boyce, Adrian J.; Casanueva-Marenco, Maria J.; van Dongen, Bart E.; Ballentine, Christopher J.; Polya, David A.

    2018-02-01

    Chronic exposure to arsenic (As) through the consumption of contaminated groundwaters is a major threat to public health in South and Southeast Asia. The source of As-affected groundwaters is important to the fundamental understanding of the controls on As mobilization and subsequent transport throughout shallow aquifers. Using the stable isotopes of hydrogen and oxygen, the source of groundwater and the interactions between various water bodies were investigated in Cambodia's Kandal Province, an area which is heavily affected by As and typical of many circum-Himalayan shallow aquifers. Two-point mixing models based on δD and δ18O allowed the relative extent of evaporation of groundwater sources to be estimated and allowed various water bodies to be broadly distinguished within the aquifer system. Model limitations are discussed, including the spatial and temporal variation in end member compositions. The conservative tracer Cl/Br is used to further discriminate between groundwater bodies. The stable isotopic signatures of groundwaters containing high As and/or high dissolved organic carbon plot both near the local meteoric water line and near more evaporative lines. The varying degrees of evaporation of high As groundwater sources are indicative of differing recharge contributions (and thus indirectly inferred associated organic matter contributions). The presence of high As groundwaters with recharge derived from both local precipitation and relatively evaporated surface water sources, such as ponds or flooded wetlands, are consistent with (but do not provide direct evidence for) models of a potential dual role of surface-derived and sedimentary organic matter in As mobilization.

  20. Catchment tracers reveal discharge, recharge and sources of groundwater-borne pollutants in a novel lake modelling approach

    Directory of Open Access Journals (Sweden)

    E. Kristensen

    2018-02-01

    Full Text Available Groundwater-borne contaminants such as nutrients, dissolved organic carbon (DOC, coloured dissolved organic matter (CDOM and pesticides can have an impact the biological quality of lakes. The sources of pollutants can, however, be difficult to identify due to high heterogeneity in groundwater flow patterns. This study presents a novel approach for fast hydrological surveys of small groundwater-fed lakes using multiple groundwater-borne tracers. Water samples were collected from the lake and temporary groundwater wells, installed every 50 m within a distance of 5–45 m to the shore, were analysed for tracer concentrations of CDOM, DOC, total dissolved nitrogen (TDN, groundwater only, total nitrogen (TN, lake only, total dissolved phosphorus (TDP, groundwater only, total phosphorus (TP, lake only, δ18O ∕ δ16O isotope ratios and fluorescent dissolved organic matter (FDOM components derived from parallel factor analysis (PARAFAC. The isolation of groundwater recharge areas was based on δ18O measurements and areas with a high groundwater recharge rate were identified using a microbially influenced FDOM component. Groundwater discharge sites and the fractions of water delivered from the individual sites were isolated with the Community Assembly via Trait Selection model (CATS. The CATS model utilized tracer measurements of TDP, TDN, DOC and CDOM from the groundwater samples and related these to the tracer measurements of TN, TP, DOC and CDOM in the lake. A direct comparison between the lake and the inflowing groundwater was possible as degradation rates of the tracers in the lake were taken into account and related to a range of water retention times (WRTs of the lake (0.25–3.5 years in 0.25-year increments. These estimations showed that WRTs above 2 years required a higher tracer concentration of inflowing water than found in any of the groundwater wells around the lake. From the estimations of inflowing tracer concentration

  1. Using multi-year reanalysis-derived recharge rates to drive a groundwater model for the Lake Tana region of Blue Nile Basin, Ethiopia

    Science.gov (United States)

    Dokou, Z.; Kheirabadi, M.; Nikolopoulos, E. I.; Moges, S. A.; Bagtzoglou, A. C.; Anagnostou, E. N.

    2017-12-01

    Ethiopia's high inter-annual variability in local precipitation has resulted in droughts and floods that stress local communities and lead to economic and food insecurity. Better predictions of water availability can supply farmers and water management authorities with critical guidance, enabling informed water resource allocation and management decisions that will in turn ensure food and water security in the region. The work presented here focuses on the development and calibration of a groundwater model of the Lake Tana region, one of the most important sub-basins of the Blue Nile River Basin. Groundwater recharge, which is the major groundwater source in the area, depends mainly on the seasonality of precipitation and the spatial variation in geology. Given that land based precipitation data are sparse in the region, two approaches for estimating groundwater recharge were used and compared that both utilize global atmospheric reanalysis driven by remote sensing datasets. In the first approach, the reanalysis precipitation dataset (ECMWF reanalysis adjusted based on GPCC) together with evapotranspiration and surface run-off estimates are used to calculate the groundwater recharge component using water budget equations. In the second approach, groundwater recharge estimates (subsurface runoff) are taken directly from a Land Surface model (FLDAS Noah), provided at a monthly time scale and 0.1˚ x 0.1˚ spatial resolution. The reanalysis derived recharge rates in both cases are incorporated into the groundwater model MODFLOW, which in combination with a Lake module that simulates the Lake water budget, offers a unique capability of improving the predictability of groundwater and lake levels in the Lake Tana basin. Model simulations using the two approaches are compared against in-situ observations of groundwater and lake levels. This modeling effort can be further used to explore climate variability effects on groundwater and lake levels and provide guidance to

  2. SLiM : an improved soil moisture balance method to simulate runoff and potential groundwater recharge processes using spatio-temporal weather and catchment characteristics

    OpenAIRE

    Wang, Lei; Barkwith, Andrew; Jackson, Christopher; Ellis, Michael

    2012-01-01

    The numerical modelling of runoff and groundwater recharge plays an important role in water resource management. The methodologies developed for these simulations should represent the key physical processes, and be applicable in a wide variety of climates for routine simulations using readily available field information. This paper describes the development of a Soil and Landuse based rainfall-runoff and recharge Model (SLiM) based on Rushton’s method – a single soil layer groundwater recharg...

  3. A time series approach to inferring groundwater recharge using the water table fluctuation method

    Science.gov (United States)

    Crosbie, Russell S.; Binning, Philip; Kalma, Jetse D.

    2005-01-01

    The water table fluctuation method for determining recharge from precipitation and water table measurements was originally developed on an event basis. Here a new multievent time series approach is presented for inferring groundwater recharge from long-term water table and precipitation records. Additional new features are the incorporation of a variable specific yield based upon the soil moisture retention curve, proper accounting for the Lisse effect on the water table, and the incorporation of aquifer drainage so that recharge can be detected even if the water table does not rise. A methodology for filtering noise and non-rainfall-related water table fluctuations is also presented. The model has been applied to 2 years of field data collected in the Tomago sand beds near Newcastle, Australia. It is shown that gross recharge estimates are very sensitive to time step size and specific yield. Properly accounting for the Lisse effect is also important to determining recharge.

  4. Use of multiple age tracers to estimate groundwater residence times and long-term recharge rates in arid southern Oman

    International Nuclear Information System (INIS)

    Müller, Th.; Osenbrück, K.; Strauch, G.; Pavetich, S.; Al-Mashaikhi, K.-S.; Herb, C.; Merchel, S.; Rugel, G.; Aeschbach, W.; Sanford, W.

    2016-01-01

    Multiple age tracers were measured to estimate groundwater residence times in the regional aquifer system underlying southwestern Oman. This area, known as the Najd, is one of the most arid areas in the world and is planned to be the main agricultural center of the Sultanate of Oman in the near future. The three isotopic age tracers "4He, "1"4C and "3"6Cl were measured in waters collected from wells along a line that extended roughly from the Dhofar Mountains near the Arabian Sea northward 400 km into the Empty Quarter of the Arabian Peninsula. The wells sampled were mostly open to the Umm Er Radhuma confined aquifer, although, some were completed in the mostly unconfined Rus aquifer. The combined results from the three tracers indicate the age of the confined groundwater is  100 ka in the central section north of the mountains, and up to and > one Ma in the Empty Quarter. The "1"4C data were used to help calibrate the "4He and "3"6Cl data. Mixing models suggest that long open boreholes north of the mountains compromise "1"4C-only interpretations there, in contrast to "4He and "3"6Cl calculations that are less sensitive to borehole mixing. Thus, only the latter two tracers from these more distant wells were considered reliable. In addition to the age tracers, δ"2H and δ"1"8O data suggest that seasonal monsoon and infrequent tropical cyclones are both substantial contributors to the recharge. The study highlights the advantages of using multiple chemical and isotopic data when estimating groundwater travel times and recharge rates, and differentiating recharge mechanisms. - Highlights: • Multiple age tracers are required for the interpretation of the groundwater system. • Different tracers are applicable along different sections of the flowpath. • Groundwater residence times >1 Ma have been determined for the northern Najd area.

  5. Physical hydrogeology and environmental isotopes to constrain the age, origins, and stability of a low-salinity groundwater lens formed by periodic river recharge: Murray Basin, Australia

    Science.gov (United States)

    Cartwright, Ian; Weaver, Tamie R.; Simmons, Craig T.; Fifield, L. Keith; Lawrence, Charles R.; Chisari, Robert; Varley, Simon

    2010-01-01

    SummaryA low-salinity (total dissolved solids, TDS, Australia. Hydraulic heads, surface water elevations, δ 18O values, major ion geochemistry, 14C activities, and 3H concentrations show that the lens is recharged from the Murray River largely through the riverbank with limited recharge through the floodplain. Recharge of the lens occurs mainly at high river levels and the low-salinity groundwater forms baseflow to some river reaches during times of low river levels. Within the lens, flow through the shallow Channel Sands and deeper Parilla Sands aquifers is sub-horizontal. While the Blanchetown Clay locally separates the Channel Sands and the Parilla Sands, the occurrence of recently recharged low-salinity groundwater below the Blanchetown Clay suggests that there is considerable leakage through this unit, implying that it is not an efficient aquitard. The lateral margin of the lens with the regional groundwater (TDS >25,000 mg/L) is marked by a hectometer to kilometer scale transition in TDS concentrations that is not stratigraphically controlled. Rather this boundary represents a mixing zone with the regional groundwater, the position of which is controlled by the rate of recharge from the river. The lens is part of an active and dynamic hydrogeological system that responds over years to decades to changes in river levels. The lens has shrunk during the drought of the late 1990s to the mid 2000s, and it will continue to shrink unless regular high flows in the Murray River are re-established. Over longer timescales, the rise of the regional water table due to land clearing will increase the hydraulic gradient between the regional groundwater and the groundwater in the lens, which will also cause it to degrade. Replacement of low-salinity groundwater in the lens with saline groundwater will ultimately increase the salinity of the Murray River reducing its utility for water supply and impacting riverine ecosystems.

  6. Natural recharge to sustainable yield from the barind aquifer: a tool in preparing effective management plan of groundwater resources.

    Science.gov (United States)

    Monirul Islam, Md; Kanungoe, P

    2005-01-01

    This paper presents the results of water balance study and aquifer simulation modeling for preliminary estimation of the recharge rate and sustainable yield for the semi arid Barind Tract region of Bangladesh. The outcomes of the study are likely to be useful for planning purposes. It is found from detailed water balance study for the area that natural recharge rates in the Barind Tract vary widely year to year. It may have resulted from the method used for the calculation. If the considered time interval had been smaller than the monthly rainfall, the results could have been different. Aquifer Simulation Modeling (ASM) for the Barind aquifer is used to estimate long-term sustainable yield of the groundwater considering limiting drawdown from the standpoint of economic pumping cost. In managing a groundwater basin efficiently and effectively, evaluation of the maximum annual groundwater yield of the basin that can be withdrawn and used without producing any undesirable effect is one of the most important issues. In investigating such recharge rate, introduction of certain terms such as sustainable yield and safe yield has been accompanied. Development of this area involves proper utilization of this vast land, which is possible only through ensured irrigation for agriculture. The Government of Bangladesh has a plan to develop irrigation facilities by optimum utilization of available ground and surface water. It is believed that the groundwater table is lowering rapidly and the whole region is in an acute state of deforestation. Indiscriminate groundwater development may accelerate deforestation trend. In this context estimation of actual natural recharge rate to the aquifer and determination of sustainable yield will assist in proper management and planning of environmentally viable abstraction schemes. It is revealed from the study that the sustainable yield of ground water (204 mm/y) is somewhat higher than the long-term annual average recharge (152.7 mm) to the

  7. Geochemistry and the Understanding of Groundwater Systems

    Science.gov (United States)

    Glynn, P. D.; Plummer, L. N.; Weissmann, G. S.; Stute, M.

    2009-12-01

    Geochemical techniques and concepts have made major contributions to the understanding of groundwater systems. Advances continue to be made through (1) development of measurement and characterization techniques, (2) improvements in computer technology, networks and numerical modeling, (3) investigation of coupled geologic, hydrologic, geochemical and biologic processes, and (4) scaling of individual observations, processes or subsystem models into larger coherent model frameworks. Many applications benefit from progress in these areas, such as: (1) understanding paleoenvironments, in particular paleoclimate, through the use of groundwater archives, (2) assessing the sustainability (recharge and depletion) of groundwater resources, and (3) their vulnerability to contamination, (4) evaluating the capacity and consequences of subsurface waste isolation (e.g. geologic carbon sequestration, nuclear and chemical waste disposal), (5) assessing the potential for mitigation/transformation of anthropogenic contaminants in groundwater systems, and (6) understanding the effect of groundwater lag times in ecosystem-scale responses to natural events, land-use changes, human impacts, and remediation efforts. Obtaining “representative” groundwater samples is difficult and progress in obtaining “representative” samples, or interpreting them, requires new techniques in characterizing groundwater system heterogeneity. Better characterization and simulation of groundwater system heterogeneity (both physical and geochemical) is critical to interpreting the meaning of groundwater “ages”; to understanding and predicting groundwater flow, solute transport, and geochemical evolution; and to quantifying groundwater recharge and discharge processes. Research advances will also come from greater use and progress (1) in the application of environmental tracers to ground water dating and in the analysis of new geochemical tracers (e.g. compound specific isotopic analyses, noble gas

  8. Impacts of Irrigation Practices on Groundwater Recharge in Mississippi Delta Using coupled SWAT-MODFLOW Model

    Science.gov (United States)

    Gao, F.; Feng, G.; Han, M.; Jenkins, J.; Ouyang, Y.

    2017-12-01

    The Lower Mississippi River alluvial plain (refers to as MS Delta), located in the northwest state of Mississippi, is one of the most productive agricultural region in the U.S. The primary crops grown in this region are soybean, corn, cotton, and rice. Approximately 80% water from the alluvial aquifer in MS Delta are withdrawn for irrigation, which makes it the most used aquifer in the State. As a result, groundwater level has declined > 6 m since 1970, which threaten the sustainability of irrigated agriculture in this region. The objectives of this study were to: 1) couple the SWAT and MODFLOW then calibrate and validate the incorporated model outputs for stream flow, groundwater level and evapotranspiration (ET) in MS Delta; 2) simulate the groundwater recharge as affected by a) conventional irrigation scheme, b) no irrigation scheme, c) ET based and soil moisture based full irrigation schedules using all groundwater, and d) ET and soil moisture based full irrigation schedule using different percentages of surface and ground water. Results indicated that the coupled model performed well during the calibration and validation for daily stream flow at three USGS gauge stations. (R2=0.7; Nash-Sutcliffe efficiency (NSE) varied from 0.6 to 0.7; Root Mean Square Error (RMSE) ranged from 20 to 27 m3/s). The values of determination coefficient R2 for groundwater level were 0.95 for calibration and 0.88 for validation, their NSE values were 0.99 and 0.93, respectively. The values of RMSE for groundwater level during the calibration and validation period were 0.51 and 0.59 m. The values of R2, NSE and RMSE between SWAT-MODFLOW simulated actual evapotranspiration (ET) and remote sensing evapotranspiration (ET) were 0.52, 0.51 and 28.1 mm. The simulated total average monthly groundwater recharge had lower values of 19 mm/month in the crop season than 30 mm/month in the crop off-growing season. The SWAT-MODFLOW can be a useful tool for not only simulating the recharge in MS

  9. Geohydrology of Big Bear Valley, California: phase 1--geologic framework, recharge, and preliminary assessment of the source and age of groundwater

    Science.gov (United States)

    Flint, Lorraine E.; Brandt, Justin; Christensen, Allen H.; Flint, Alan L.; Hevesi, Joseph A.; Jachens, Robert; Kulongoski, Justin T.; Martin, Peter; Sneed, Michelle

    2012-01-01

    The Big Bear Valley, located in the San Bernardino Mountains of southern California, has increased in population in recent years. Most of the water supply for the area is pumped from the alluvial deposits that form the Big Bear Valley groundwater basin. This study was conducted to better understand the thickness and structure of the groundwater basin in order to estimate the quantity and distribution of natural recharge to Big Bear Valley. A gravity survey was used to estimate the thickness of the alluvial deposits that form the Big Bear Valley groundwater basin. This determined that the alluvial deposits reach a maximum thickness of 1,500 to 2,000 feet beneath the center of Big Bear Lake and the area between Big Bear and Baldwin Lakes, and decrease to less than 500 feet thick beneath the eastern end of Big Bear Lake. Interferometric Synthetic Aperture Radar (InSAR) was used to measure pumping-induced land subsidence and to locate structures, such as faults, that could affect groundwater movement. The measurements indicated small amounts of land deformation (uplift and subsidence) in the area between Big Bear Lake and Baldwin Lake, the area near the city of Big Bear Lake, and the area near Sugarloaf, California. Both the gravity and InSAR measurements indicated the possible presence of subsurface faults in subbasins between Big Bear and Baldwin Lakes, but additional data are required for confirmation. The distribution and quantity of groundwater recharge in the area were evaluated by using a regional water-balance model (Basin Characterization Model, or BCM) and a daily rainfall-runoff model (INFILv3). The BCM calculated spatially distributed potential recharge in the study area of approximately 12,700 acre-feet per year (acre-ft/yr) of potential in-place recharge and 30,800 acre-ft/yr of potential runoff. Using the assumption that only 10 percent of the runoff becomes recharge, this approach indicated there is approximately 15,800 acre-ft/yr of total recharge in

  10. Monitoring and modeling infiltration-recharge dynamics of managed aquifer recharge with desalinated seawater

    Science.gov (United States)

    Ganot, Yonatan; Holtzman, Ran; Weisbrod, Noam; Nitzan, Ido; Katz, Yoram; Kurtzman, Daniel

    2017-09-01

    We study the relation between surface infiltration and groundwater recharge during managed aquifer recharge (MAR) with desalinated seawater in an infiltration pond, at the Menashe site that overlies the northern part of the Israeli Coastal Aquifer. We monitor infiltration dynamics at multiple scales (up to the scale of the entire pond) by measuring the ponding depth, sediment water content and groundwater levels, using pressure sensors, single-ring infiltrometers, soil sensors, and observation wells. During a month (January 2015) of continuous intensive MAR (2.45 × 106 m3 discharged to a 10.7 ha area), groundwater level has risen by 17 m attaining full connection with the pond, while average infiltration rates declined by almost 2 orders of magnitude (from ˜ 11 to ˜ 0.4 m d-1). This reduction can be explained solely by the lithology of the unsaturated zone that includes relatively low-permeability sediments. Clogging processes at the pond-surface - abundant in many MAR operations - are negated by the high-quality desalinated seawater (turbidity ˜ 0.2 NTU, total dissolved solids ˜ 120 mg L-1) or negligible compared to the low-permeability layers. Recharge during infiltration was estimated reasonably well by simple analytical models, whereas a numerical model was used for estimating groundwater recharge after the end of infiltration. It was found that a calibrated numerical model with a one-dimensional representative sediment profile is able to capture MAR dynamics, including temporal reduction of infiltration rates, drainage and groundwater recharge. Measured infiltration rates of an independent MAR event (January 2016) fitted well to those calculated by the calibrated numerical model, showing the model validity. The successful quantification methodologies of the temporal groundwater recharge are useful for MAR practitioners and can serve as an input for groundwater flow models.

  11. Quantifying Modern Recharge to the Nubian Sandstone Aquifer System: Inferences from GRACE and Land Surface Models

    Science.gov (United States)

    Mohamed, A.; Sultan, M.; Ahmed, M.; Yan, E.

    2014-12-01

    The Nubian Sandstone Aquifer System (NSAS) is shared by Egypt, Libya, Chad and Sudanand is one of the largest (area: ~ 2 × 106 km2) groundwater systems in the world. Despite its importance to the population of these countries, major hydrological parameters such as modern recharge and extraction rates remain poorly investigated given: (1) the large extent of the NSAS, (2) the absence of comprehensive monitoring networks, (3) the general inaccessibility of many of the NSAS regions, (4) difficulties in collecting background information, largely included in unpublished governmental reports, and (5) limited local funding to support the construction of monitoring networks and/or collection of field and background datasets. Data from monthly Gravity Recovery and Climate Experiment (GRACE) gravity solutions were processed (Gaussian smoothed: 100 km; rescaled) and used to quantify the modern recharge to the NSAS during the period from January 2003 to December 2012. To isolate the groundwater component in GRACE data, the soil moisture and river channel storages were removed using the outputs from the most recent Community Land Model version 4.5 (CLM4.5). GRACE-derived recharge calculations were performed over the southern NSAS outcrops (area: 835 × 103 km2) in Sudan and Chad that receive average annual precipitation of 65 km3 (77.5 mm). GRACE-derived recharge rates were estimated at 2.79 ± 0.98 km3/yr (3.34 ± 1.17 mm/yr). If we take into account the total annual extraction rates (~ 0.4 km3; CEDARE, 2002) from Chad and Sudan the average annual recharge rate for the NSAS could reach up to ~ 3.20 ± 1.18 km3/yr (3.84 ± 1.42 mm/yr). Our recharge rates estimates are similar to those calculated using (1) groundwater flow modelling in the Central Sudan Rift Basins (4-8 mm/yr; Abdalla, 2008), (2) WaterGAP global scale groundwater recharge model (plans are underway for the deployment of a GRACE follow-On and GRACE-II missions, we suggest that within the next few years, GRACE

  12. Estimates of ground-water recharge rates for two small basins in central Nevada

    International Nuclear Information System (INIS)

    Lichty, R.W.; McKinley, P.W.

    1995-01-01

    Estimates of ground-water recharge rates developed from hydrologic modeling studies are presented for 3-Springs and East Stewart basins, two small basins (analog sites) located in central Nevada. The analog-site studies were conducted to aid in the estimation of recharge to the paleohydrologic regime associated with ground water in the vicinity of Yucca Mountain under wetter climatic conditions. The two analog sites are located to the north and at higher elevations than Yucca Mountain, and the prevailing (current) climatic conditions at these sites is thought to be representative of the possible range of paleoclimatic conditions in the general area of Yucca Mountain during the Quaternary. Two independent modeling approaches were conducted at each of the analog sites using observed hydrologic data on precipitation, temperature, solar radiation, stream discharge, and chloride-ion water chemistry for a 6-year study period (October 1986 through September 1992). Both models quantify the hydrologic water-balance equation and yield estimates of ground-water recharge, given appropriate input data. Results of the modeling approaches support the conclusion that reasonable estimates of average-annual recharge to ground water range from about 1 to 3 centimeters per year for 3-Springs basin (the drier site), and from about 30 to 32 centimeters per year for East Stewart basin (the wetter site). The most reliable results are those derived from a reduced form of the chloride-ion model because they reflect integrated, basinwide processes in terms of only three measured variables: precipitation amount, precipitation chemistry, and streamflow chemistry

  13. Experimental and numerical investigations of soil water balance at the hinterland of the Badain Jaran Desert for groundwater recharge estimation

    Science.gov (United States)

    Hou, Lizhu; Wang, Xu-Sheng; Hu, Bill X.; Shang, Jie; Wan, Li

    2016-09-01

    Quantification of groundwater recharge from precipitation in the huge sand dunes is an issue in accounting for regional water balance in the Badain Jaran Desert (BJD) where about 100 lakes exist between dunes. In this study, field observations were conducted on a sand dune near a large saline lake in the BJD to investigate soil water movement through a thick vadose zone for groundwater estimation. The hydraulic properties of the soils at the site were determined using in situ experiments and laboratory measurements. A HYDRUS-1D model was built up for simulating the coupling processes of vertical water-vapor movement and heat transport in the desert soil. The model was well calibrated and validated using the site measurements of the soil water and temperature at various depths. Then, the model was applied to simulate the vertical flow across a 3-m-depth soil during a 53-year period under variable climate conditions. The simulated flow rate at the depth is an approximate estimation of groundwater recharge from the precipitation in the desert. It was found that the annual groundwater recharge would be 11-30 mm during 1983-2012, while the annual precipitation varied from 68 to 172 mm in the same period. The recharge rates are significantly higher than those estimated from the previous studies using chemical information. The modeling results highlight the role of the local precipitation as an essential source of groundwater in the BJD.

  14. The aquifer recharge: an overview of the legislative and planning aspect.

    Science.gov (United States)

    De Giglio, O; Caggiano, G; Apollonio, F; Marzella, A; Brigida, S; Ranieri, E; Lucentini, L; Uricchio, V F; Montagna, M T

    2018-01-01

    In most regions of the world, safeguarding groundwater resources is a serious issue, particularly in coastal areas where groundwater is the main water source for drinking, irrigation and industry. Water availability depends on climate, topography and geology. The aim of this paper is to evaluate aquifer recharge as a possible strategy to relieve water resource scarcity. Natural aquifer recharge is defined as the downward flow of water reaching the water table, increasing the groundwater reservoir. Hydro-meteorological factors (rainfall, evapotranspiration and runoff) may alter natural recharge processes. Artificial aquifer recharge is a process by which surface water is introduced with artificial systems underground to fill an aquifer. As a consequence of global warming that has increased the frequency and severity of natural disasters like the drought, the impacts of climate change and seasonality, the artificial recharge has been considered as a viable option. Different direct and indirect techniques can be used, and the choice depends on the hydrologic characteristics of a specific area. In Italy, Legislative Decree no. 152/06 plans artificial aquifer recharge as an additional measure in water management, and Decree no. 100/2016 establishes quantitative and qualitative conditions for recharge. Many projects examine aquifer recharge, such us WADIS-MAR in the southern Mediterranean region, WARBO in Italy and municipal wastewater treatment project in Apulia, a southern Italian region. However, aside from groundwater recharge, the community must foster a spirit of cooperation to manage groundwater as a sustainable resource.

  15. Estimation of groundwater recharge via deuterium labelling in the semi-arid Cuvelai-Etosha Basin, Namibia.

    Science.gov (United States)

    Beyer, Matthias; Gaj, Marcel; Hamutoko, Josefina Tulimeveva; Koeniger, Paul; Wanke, Heike; Himmelsbach, Thomas

    2015-01-01

    The stable water isotope deuterium ((2)H) was applied as an artificial tracer ((2)H2O) in order to estimate groundwater recharge through the unsaturated zone and describe soil water movement in a semi-arid region of northern central Namibia. A particular focus of this study was to assess the spatiotemporal persistence of the tracer when applied in the field on a small scale under extreme climatic conditions and to propose a method to obtain estimates of recharge in data-scarce regions. At two natural sites that differ in vegetation cover, soil and geology, 500 ml of a 70% (2)H2O solution was irrigated onto water saturated plots. The displacement of the (2)H peak was analyzed 1 and 10 days after an artificial rain event of 20 mm as well as after the rainy season. Results show that it is possible to apply the peak displacement method for the estimation of groundwater recharge rates in semi-arid environments via deuterium labelling. Potential recharge for the rainy season 2013/2014 was calculated as 45 mm a(-1) at 5.6 m depth and 40 mm a(-1) at 0.9 m depth at the two studied sites, respectively. Under saturated conditions, the artificial rain events moved 2.1 and 0.5 m downwards, respectively. The tracer at the deep sand site (site 1) was found after the rainy season at 5.6 m depth, corresponding to a displacement of 3.2 m. This equals in an average travel velocity of 2.8 cm d(-1) during the rainy season at the first site. At the second location, the tracer peak was discovered at 0.9 m depth; displacement was found to be only 0.4 m equalling an average movement of 0.2 cm d(-1) through the unsaturated zone due to an underlying calcrete formation. Tracer recovery after one rainy season was found to be as low as 3.6% at site 1 and 1.9% at site 2. With an in situ measuring technique, a three-dimensional distribution of (2)H after the rainy season could be measured and visualized. This study comprises the first application of the peak displacement method using a

  16. Drought-related vulnerability and risk assessment of groundwater in Belgium: estimation of the groundwater recharge and crop yield vulnerability with the B-CGMS

    Science.gov (United States)

    Jacquemin, Ingrid; Verbeiren, Boud; Vanderhaegen, Sven; Canters, Frank; Vermeiren, Karolien; Engelen, Guy; Huysmans, Marijke; Batelaan, Okke; Tychon, Bernard

    2016-04-01

    Due to common belief that regions under temperate climate are not affected by (meteorological and groundwater) drought, these events and their impacts remain poorly studied: in the GroWaDRISK, we propose to take stock of this question. We aim at providing a better understanding of the influencing factors (land use and land cover changes, water demand and climate) and the drought-related impacts on the environment, water supply and agriculture. The study area is located in the North-East of Belgium, corresponding approximatively to the Dijle and Demer catchments. To establish an overview of the groundwater situation, we assess the system input: the recharge. To achieve this goal, two models, B-CGMS and WetSpass are used to evaluate the recharge, respectively, over agricultural land and over the remaining areas, as a function of climate and for various land uses and land covers. B-CGMS, which is an adapted version for Belgium of the European Crop Growth Monitoring System, is used for assessing water recharge at a daily timestep and under different agricultural lands: arable land (winter wheat, maize...), orchards, horticulture and floriculture and for grassland. B-CGMS is designed to foresee crop yield and obviously it studies the impact of drought on crop yield and raises issues for the potential need of irrigation. For both yields and water requirements, the model proposes a potential mode, driven by temperature and solar radiation, and a water-limited mode for which water availability can limit crop growth. By this way, we can identify where and when water consumption and yield are not optimal, in addition to the Crop Water Stress Index. This index is calculated for a given crop, as the number of days affected by water stress during the growth sensitive period. Both recharge and crop yield are assessed for the current situation (1980 - 2012), taking into account the changing land use/land cover, in terms of areas and localization of the agricultural land and where

  17. Evaluating impacts of recharging partially treated wastewater on groundwater aquifer in semi-arid region by integration of monitoring program and GIS technique.

    Science.gov (United States)

    Alslaibi, Tamer M; Kishawi, Yasser; Abunada, Ziyad

    2017-05-01

    The current study investigates the impact of recharging of partially treated wastewater through an infiltration basin on the groundwater aquifer quality parameters. A monitoring program supported by a geographic information analysis (GIS) tool was used to conduct this study. Groundwater samples from the entire surrounding boreholes located downstream the infiltration basin, in addition to samples from the recharged wastewater coming from the Beit Lahia wastewater treatment (BLWWTP), were monitored and analysed between 2011 and 2014. The analysis was then compared with the available historical data since 2008. Results revealed a groundwater replenishment with the groundwater level increased by 1.0-2.0 m during the study period. It also showed a slight improvement in the groundwater quality parameters, mainly a decrease in TDS, Cl - and NO 3 - levels by 5.5, 17.1 and 20%, respectively, resulting from the relatively better quality of the recharged wastewater. Nevertheless, the level of boron and ammonium in the groundwater wells showed a significant increase over time by 96 and 100%, respectively. Moreover, the infiltration rate was slowed down in time due to the relatively high level of total suspended solid (TSS) in the infiltrated wastewater.

  18. Effects of Projected Future Climate Change on Groundwater Recharge and Storage for Two Coastal Aquifers in Guanacaste Province, Costa Rica

    Science.gov (United States)

    Kolb, C.

    2017-12-01

    Climate change is expected to pose a significant threat to water resources in the future. Guanacaste Province, located in northwestern Costa Rica, has a unique climate that is influenced by the Pacific Ocean and Caribbean Sea, as well as the Central Cordillera mountain range. Although the region experiences a marked rainy season between May and November, the hot, dry summers often stress water resources. Climate change projections suggest increased temperatures and reduced precipitation for the region, which will further stress water supplies. This study focuses on the effects of climate change on groundwater resources for two coastal aquifers, Potrero and Brasilito. The UZF model package coupled with the finite difference groundwater flow model MODFLOW were used to evaluate the effect of climate change on groundwater recharge and storage. A potential evapotranspiration model was used to estimate groundwater infiltration rates used in the MODFLOW model. Climate change projections for temperature, precipitation, and sea level rise were used to develop climate scenarios, which were compared to historical data. Preliminary results indicate that climate change could reduce future recharge, especially during the dry season. Additionally, the coastal aquifers are at increased risk of reduced storage and increased salinization due to the reductions in groundwater recharge and sea level rise. Climate change could also affect groundwater quality in the region, disrupting the ecosystem and impairing a primary source of drinking water.

  19. Managed aquifer recharge by a check dam to improve the quality of fluoride-rich groundwater: a case study from southern India.

    Science.gov (United States)

    Gowrisankar, G; Jagadeshan, G; Elango, L

    2017-04-01

    In many regions around the globe, including India, degradation in the quality of groundwater is of great concern. The objective of this investigation is to determine the effect of recharge from a check dam on quality of groundwater in a region of Krishnagiri District of Tamil Nadu State, India. For this study, water samples from 15 wells were periodically obtained and analysed for major ions and fluoride concentrations. The amount of major ions present in groundwater was compared with the drinking water guideline values of the Bureau of Indian Standards. With respect to the sodium and fluoride concentrations, 38% of groundwater samples collected was not suitable for direct use as drinking water. Suitability of water for agricultural use was determined considering the electrical conductivity, sodium adsorption ratio, sodium percentage, permeability index, Wilcox and United States Salinity Laboratory diagrams. The influence of freshwater recharge from the dam is evident as the groundwater in wells nearer to the check dam was suitable for both irrigation and domestic purposes. However, the groundwater away from the dam had a high ionic composition. This study demonstrated that in other fluoride-affected areas, the concentration can be reduced by dilution with the construction of check dams as a measure of managed aquifer recharge.

  20. Optimization of an artificial-recharge-pumping system for water supply in the Maghaway Valley, Cebu, Philippines

    Science.gov (United States)

    Kawo, Nafyad Serre; Zhou, Yangxiao; Magalso, Ronnell; Salvacion, Lasaro

    2018-05-01

    A coupled simulation-optimization approach to optimize an artificial-recharge-pumping system for the water supply in the Maghaway Valley, Cebu, Philippines, is presented. The objective is to maximize the total pumping rate through a system of artificial recharge and pumping while meeting constraints such as groundwater-level drawdown and bounds on pumping rates at each well. The simulation models were coupled with groundwater management optimization to maximize production rates. Under steady-state natural conditions, the significant inflow to the aquifer comes from river leakage, whereas the natural discharge is mainly the subsurface outflow to the downstream area. Results from the steady artificial-recharge-pumping simulation model show that artificial recharge is about 20,587 m3/day and accounts for 77% of total inflow. Under transient artificial-recharge-pumping conditions, artificial recharge varies between 14,000 and 20,000 m3/day depending on the wet and dry seasons, respectively. The steady-state optimisation results show that the total optimal abstraction rate is 37,545 m3/day and artificial recharge is increased to 29,313 m3/day. The transient optimization results show that the average total optimal pumping rate is 36,969 m3/day for the current weir height. The transient optimization results for an increase in weir height by 1 and 2 m show that the average total optimal pumping rates are increased to 38,768 and 40,463 m3/day, respectively. It is concluded that the increase in the height of the weir can significantly increase the artificial recharge rate and production rate in Maghaway Valley.

  1. Estimated rates of groundwater recharge to the Chicot, Evangeline and Jasper aquifers by using environmental tracers in Montgomery and adjacent counties, Texas, 2008 and 2011

    Science.gov (United States)

    Oden, Timothy D.; Truini, Margot

    2013-01-01

    Montgomery County is in the northern part of the Houston, Texas, metropolitan area, the fourth most populous metropolitan area in the United States. As populations have increased since the 1980s, groundwater has become an important resource for public-water supply and industry in the rapidly growing area of Montgomery County. Groundwater availability from the Gulf Coast aquifer system is a primary concern for water managers and community planners in Montgomery County and requires a better understanding of the rate of recharge to the system. The Gulf Coast aquifer system in Montgomery County consists of the Chicot, Evangeline, and Jasper aquifers, the Burkeville confining unit, and underlying Catahoula confining system. The individual sand and clay sequences of the aquifers composing the Gulf Coast aquifer system are not laterally or vertically continuous on a regional scale; however, on a local scale, individual sand and clay lenses can extend over several miles. The U.S. Geological Survey, in cooperation with the Lone Star Groundwater Conservation District, collected groundwater-quality samples from selected wells within or near Montgomery County in 2008 and analyzed these samples for concentrations of chlorofluorocarbons (CFCs), sulfur hexafluoride (SF6), tritium (3H), helium-3/tritium (3He/3H), helium-4 (4He), and dissolved gases (DG) that include argon, carbon dioxide, methane, nitrogen and oxygen. Groundwater ages, or apparent age, representing residence times since time of recharge, were determined by using the assumption of a piston-flow transport model. Most of the environmental tracer data indicated the groundwater was recharged prior to the 1950s, limiting the usefulness of CFCs, SF6, and 3H concentrations as tracers. In many cases, no tracer was usable at a well for the purpose of estimating an apparent age. Wells not usable for estimating an apparent age were resampled in 2011 and analyzed for concentrations of major ions and carbon-14 (14C). At six of

  2. Groundwater Recharge Assessment in a Remote Region of Colombia Through Citizen Science

    Science.gov (United States)

    Gomez, A. M.; Wise, E.; Riveros-Iregui, D.

    2017-12-01

    Understanding water dynamic and storage is essential for decision making in hydrology issues. In remote groundwater-dependent regions affected by population displacement and land over exploitation, especially in developing economies, limited data hinders the production of information necessary to formulate and implement effective water management plans. The community science research approach, which seeks to solve scientific questions with the participation of the community at various levels, represents an opportunity in these regions. We present results of a citizen science project developed to improve the conceptualization of groundwater flow path and to estimate the monthly direct recharge to the shallow aquifer in a remote rural region, the Man River watershed, located in one of the last foothills between the Western and Central Andes cordillera in Colombia. This project was conducted by: i) implementing a water level monitoring network aided by the community to collect weekly data from 2007 to 2010; ii) comparing the precipitation data and water table time series to identify the response of the shallow aquifer to the wet season; iii) conceptualizing specific groundwater-surface interactions through water table spatial analysis; and iv) estimating direct groundwater recharge using the Water Table Fluctuation method. Water quality test results were shared with the local community. Results show that groundwater interacts with the main tributaries to the Man River. Two scenarios were identified related to water table temporal behavior: (1) the water table rises during the transition from the dry to the wet season (between March and April), and (2) it increases one month after this transition. In general, groundwater levels descend in November, which is the end of the wet season. The work with the community provided useful insights for interpreting the collected data and allowed for information exchange concerning the groundwater quality and methods for improving

  3. Monitoring and modeling infiltration–recharge dynamics of managed aquifer recharge with desalinated seawater

    Directory of Open Access Journals (Sweden)

    Y. Ganot

    2017-09-01

    Full Text Available We study the relation between surface infiltration and groundwater recharge during managed aquifer recharge (MAR with desalinated seawater in an infiltration pond, at the Menashe site that overlies the northern part of the Israeli Coastal Aquifer. We monitor infiltration dynamics at multiple scales (up to the scale of the entire pond by measuring the ponding depth, sediment water content and groundwater levels, using pressure sensors, single-ring infiltrometers, soil sensors, and observation wells. During a month (January 2015 of continuous intensive MAR (2.45  ×  106 m3 discharged to a 10.7 ha area, groundwater level has risen by 17 m attaining full connection with the pond, while average infiltration rates declined by almost 2 orders of magnitude (from  ∼  11 to  ∼  0.4 m d−1. This reduction can be explained solely by the lithology of the unsaturated zone that includes relatively low-permeability sediments. Clogging processes at the pond-surface – abundant in many MAR operations – are negated by the high-quality desalinated seawater (turbidity  ∼  0.2 NTU, total dissolved solids  ∼  120 mg L−1 or negligible compared to the low-permeability layers. Recharge during infiltration was estimated reasonably well by simple analytical models, whereas a numerical model was used for estimating groundwater recharge after the end of infiltration. It was found that a calibrated numerical model with a one-dimensional representative sediment profile is able to capture MAR dynamics, including temporal reduction of infiltration rates, drainage and groundwater recharge. Measured infiltration rates of an independent MAR event (January 2016 fitted well to those calculated by the calibrated numerical model, showing the model validity. The successful quantification methodologies of the temporal groundwater recharge are useful for MAR practitioners and can serve as an input for groundwater flow models.

  4. A preliminary analysis of the groundwater recharge to the Karoo formations, mid-Zambesi basin, Zimbabwe

    DEFF Research Database (Denmark)

    Larsen, Flemming; Owen, R.; Dahlin, T.

    2002-01-01

    A multi-disciplinary study is being carried out on recharge to the Karoo sandstone aquifer in the western part of Zimbabwe, where recharge is controlled by the presence of a thick, confining basalt layer. The aquifer is geographically extensive, and has been identified throughout the southern part......, before it dips below an impervious basalt cover. However, resistivity profiling shows that the basalt at the basin margin is weathered and fractured, and probably permeable, while the basalt deeper into the basin is fresh, solid and impermeable. Field and laboratory analysis of 22 groundwater samples......–130 mm/yr, with an average value of 25 mm/yr. Preliminary results of recharge estimate using 36Cl data suggests lower direct infiltration rates, but further studies are needed. The combination of hydro-chemical, isotopic and geophysical investigations show that the recharge area extends well beyond...

  5. Evaluation of the Benefit of Flood Reduction by Artificial Groundwater Recharge Lake Operation in a Coastal Area

    Science.gov (United States)

    Chen, Ching-Nuo; Tsai, Chih-Heng

    2017-04-01

    Inundation disasters often occur in the southwestern coastal plains of Taiwan. The coastal plains suffers mostly from land-subsidence, surface water is difficult to be drained during the typhoon period, leading to more severe flood disasters. Global climate warming has become more significant, which in turn has resulted in the increase in amplitude and frequency of climate change related disasters. In addition, climate change also induces a rise in sea water level year by year. The rise in sea water level does not only weakens the function of existing drainage system but also increases tidal levels and storm tide levels, which increases the probability and amount of inundation disasters. The serious land subsidence area at Linbian river basin was selected as the study area. An artificial groundwater recharge lake has been set up in Linbian river basin by Pingtung government. The development area of this lake is 58 hectare and the storage volume is 2.1 million cubic meters (210 × 104m3). The surface water from Linbian basin during a wet season is led into the artificial groundwater recharge lake by water diversion project, and then employ special hydro-geological conditions of the area for groundwater recharge, increase groundwater supply and decrease land subsidence rate, and incidentally some of the flood diversion, detention, reduce flooding. In this study, a Real-time Interactive Inundation Model is applied to simulate different flooding storage volume and gate operations to estimate the benefits of flood mitigation. According to the simulation results, the hydrograph shape, peak-flow reduction and time lag to peak of the flood reduction hydrograph into the lake are apparently different for each case of different gate operation at the same storage volume. Therefore, the effect of flood control and disaster mitigation is different. The flood control and disaster mitigation benefits are evaluated by different operation modes, which provide decision makers to

  6. Current and future groundwater recharge in West Africa as estimated from a range of coupled climate model outputs

    Science.gov (United States)

    Verhoef, Anne; Cook, Peter; Black, Emily; Macdonald, David; Sorensen, James

    2017-04-01

    This research addresses the terrestrial water balance for West Africa. Emphasis is on the prediction of groundwater recharge and how this may change in the future, which has relevance to the management of surface and groundwater resources. The study was conducted as part of the BRAVE research project, "Building understanding of climate variability into planning of groundwater supplies from low storage aquifers in Africa - Second Phase", funded under the NERC/DFID/ESRC Programme, Unlocking the Potential of Groundwater for the Poor (UPGro). We used model output data of water balance components (precipitation, surface and subsurface run-off, evapotranspiration and soil moisture content) from ERA-Interim/ERA-LAND reanalysis, CMIP5, and high resolution model runs with HadGEM3 (UPSCALE; Mizielinski et al., 2014), for current and future time-periods. Water balance components varied widely between the different models; variation was particularly large for sub-surface runoff (defined as drainage from the bottom-most soil layer of each model). In-situ data for groundwater recharge obtained from the peer-reviewed literature were compared with the model outputs. Separate off-line model sensitivity studies with key land surface models were performed to gain understanding of the reasons behind the model differences. These analyses were centered on vegetation, and soil hydraulic parameters. The modelled current and future recharge time series that had the greatest degree of confidence were used to examine the spatiotemporal variability in groundwater storage. Finally, the implications for water supply planning were assessed. Mizielinski, M.S. et al., 2014. High-resolution global climate modelling: the UPSCALE project, a large-simulation campaign. Geoscientific Model Development, 7(4), pp.1629-1640.

  7. Linking Groundwater Use and Stress to Specific Crops Using the Groundwater Footprint in the Central Valley and High Plains Aquifer Systems, U.S.

    Science.gov (United States)

    Wada, Y.; Esnault, L.; Gleeson, T.; Heinke, J.; Gerten, D.; Flanary, E.; Bierkens, M. F.; Van Beek, L. P.

    2014-12-01

    A number of aquifers worldwide are being depleted, mainly by agricultural activities, yet groundwater stress has not been explicitly linked to specific agricultural crops. Using the newly-developed concept of the groundwater footprint (the area required to sustain groundwater use and groundwater-dependent ecosystem services), we develop a methodology to derive crop-specific groundwater footprints. We illustrate this method by calculating high resolution groundwater footprint estimates of crops in two heavily used aquifer systems: the Central Valley and High Plains, U.S. In both aquifer systems, hay and haylage, corn and cotton have the largest groundwater footprints, which highlights that most of the groundwater stress is induced by crops meant for cattle feed. Our results are coherent with other studies in the High Plains but suggest lower groundwater stress in the Central Valley, likely due to artificial recharge from surface water diversions which were not taken into account in previous estimates. Uncertainties of recharge and irrigation application efficiency contribute the most to the total relative uncertainty of the groundwater footprint to aquifer area ratios. Our results and methodology will be useful for hydrologists, water resource managers, and policy makers concerned with which crops are causing the well-documented groundwater stress in semiarid to arid agricultural regions around the world.

  8. Groundwater recharge dynamics in unsaturated fractured chalk: a case study

    Science.gov (United States)

    Cherubini, Claudia; Pastore, Nicola; Giasi, Concetta I.; Allegretti, Nicolaetta M.

    2016-04-01

    The heterogeneity of the unsaturated zone controls its hydraulic response to rainfall and the extent to which pollutants are delayed or attenuated before reaching groundwater. It plays therefore a very important role in the recharge of aquifers and the transfer of pollutants because of the presence of temporary storage zones and preferential flows. A better knowledge of the physical processes in the unsaturated zone would allow an improved assessment of the natural recharge in a heterogeneous aquifer and of its vulnerability to surface-applied pollution. The case study regards the role of the thick unsaturated zone of the Cretaceous chalk aquifer in Picardy (North of France) that controls the hydraulic response to rainfall. In the North Paris Basin, much of the recharge must pass through a regional chalk bed that is composed of a porous matrix with embedded fractures. Different types of conceptual models have been formulated to explain infiltration and recharge processes in the unsaturated fractured rock. The present study analyses the episodic recharge in fractured Chalk aquifer using the kinematic diffusion theory to predict water table fluctuation in response to rainfall. From an analysis of the data, there is the evidence of 1) a seasonal behavior characterized by a constant increase in the water level during the winter/spring period and a recession period, 2) a series of episodic behaviors during the summer/autumn. Kinematic diffusion models are useful for predict preferential fluxes and dynamic conditions. The presented approach conceptualizes the unsaturated flow as a combination of 1) diffusive flow refers to the idealized portion of the pore space of the medium within the flow rate is driven essentially by local gradient of potential; 2) preferential flow by which water moves across macroscopic distances through conduits of macropore length.

  9. Assessing recharge using remotely sensed data in the Guarani Aquifer System outcrop zone

    Science.gov (United States)

    Lucas, M. C.; Oliveira, P. T. S.; Melo, D. D.; Wendland, E.

    2014-12-01

    Groundwater recharge is an essential hydrology component for sustainable water withdrawal from an aquifer. The Guarani Aquifer System (GAS) is the largest (~1.2 million km2) transboundary groundwater reservoir in South America, supplying freshwater to four countries: Brazil, Argentina, Paraguay and Uruguay. However, recharge in the GAS outcrop zones is one of the least known hydrological variables, in part because studies from hydrological data are scarce or nonexistent. We assess recharge using the water-budget as the difference of precipitation (P) and evapotranspiration (ET). Data is derived from remotely sensed estimates of P (TRMM 3B42 V7) and ET (MOD16) in the Onça Creek watershed over the 2004­-12 period. This is an upland-flat watershed (slope steepness < 1%) dominated by sand soils and representative of the GAS outcrop zones. We compared the remote sensing approach against Water Table Fluctuation (WTF) method and another water-budget using ground-based measurements. Uncertainty propagation analysis were also performed. On monthly basis, TRMM P exhibited a great agreement with ground-based P data (R2 = 0.86 and RMSE = 41 mm). Historical (2004-12) mean(±sd) satellite-based recharge (Rsat) was 537(±224) mm y-1, while ground-based recharge using water-budget (Rgr) and WTF (Rwtf) method was 469 mm y-1 and 311(±150) mm y-1, respectively. We found that ~440 mm y-1 is a reasonable historical mean (between Rsat, Rgr and Rwtf) recharge for the study area over 2004-2012 period. The latter mean recharge estimate is about 29% of the mean historical P (1,514 mm y-1). Our results provide the first insight about an intercomparison of water budget from remote sensing and measured data to estimate recharge in the GAS outcrop zone. These results should be useful for future studies on assessing recharge in the GAS outcrop zones. Since accurate and precise recharge estimation still is a gap, our recharge satellite-based is considered acceptable for the Onça Creek

  10. Regional groundwater-flow model of the Redwall-Muav, Coconino, and alluvial basin aquifer systems of northern and central Arizona

    Science.gov (United States)

    Pool, D.R.; Blasch, Kyle W.; Callegary, James B.; Leake, Stanley A.; Graser, Leslie F.

    2011-01-01

    A numerical flow model (MODFLOW) of the groundwater flow system in the primary aquifers in northern Arizona was developed to simulate interactions between the aquifers, perennial streams, and springs for predevelopment and transient conditions during 1910 through 2005. Simulated aquifers include the Redwall-Muav, Coconino, and basin-fill aquifers. Perennial stream reaches and springs that derive base flow from the aquifers were simulated, including the Colorado River, Little Colorado River, Salt River, Verde River, and perennial reaches of tributary streams. Simulated major springs include Blue Spring, Del Rio Springs, Havasu Springs, Verde River headwater springs, several springs that discharge adjacent to major Verde River tributaries, and many springs that discharge to the Colorado River. Estimates of aquifer hydraulic properties and groundwater budgets were developed from published reports and groundwater-flow models. Spatial extents of aquifers and confining units were developed from geologic data, geophysical models, a groundwater-flow model for the Prescott Active Management Area, drill logs, geologic logs, and geophysical logs. Spatial and temporal distributions of natural recharge were developed by using a water-balance model that estimates recharge from direct infiltration. Additional natural recharge from ephemeral channel infiltration was simulated in alluvial basins. Recharge at wastewater treatment facilities and incidental recharge at agricultural fields and golf courses were also simulated. Estimates of predevelopment rates of groundwater discharge to streams, springs, and evapotranspiration by phreatophytes were derived from previous reports and on the basis of streamflow records at gages. Annual estimates of groundwater withdrawals for agriculture, municipal, industrial, and domestic uses were developed from several sources, including reported withdrawals for nonexempt wells, estimated crop requirements for agricultural wells, and estimated per

  11. High Recharge Areas in the Choushui River Alluvial Fan (Taiwan Assessed from Recharge Potential Analysis and Average Storage Variation Indexes

    Directory of Open Access Journals (Sweden)

    Jui-Pin Tsai

    2015-03-01

    Full Text Available High recharge areas significantly influence the groundwater quality and quantity in regional groundwater systems. Many studies have applied recharge potential analysis (RPA to estimate groundwater recharge potential (GRP and have delineated high recharge areas based on the estimated GRP. However, most of these studies define the RPA parameters with supposition, and this represents a major source of uncertainty for applying RPA. To objectively define the RPA parameter values without supposition, this study proposes a systematic method based on the theory of parameter identification. A surrogate variable, namely the average storage variation (ASV index, is developed to calibrate the RPA parameters, because of the lack of direct GRP observations. The study results show that the correlations between the ASV indexes and computed GRP values improved from 0.67 before calibration to 0.85 after calibration, thus indicating that the calibrated RPA parameters represent the recharge characteristics of the study area well; these data also highlight how defining the RPA parameters with ASV indexes can help to improve the accuracy. The calibrated RPA parameters were used to estimate the GRP distribution of the study area, and the GRP values were graded into five levels. High and excellent level areas are defined as high recharge areas, which composed 7.92% of the study area. Overall, this study demonstrates that the developed approach can objectively define the RPA parameters and high recharge areas of the Choushui River alluvial fan, and the results should serve as valuable references for the Taiwanese government in their efforts to conserve the groundwater quality and quantity of the study area.

  12. A water-budget approach to estimating potential groundwater recharge from two domestic sewage disposal fields in eastern Bernalillo County, New Mexico, 2011-12

    Science.gov (United States)

    Crilley, Dianna M.; Collison, Jake W.

    2015-08-04

    Eastern Bernalillo County, New Mexico, is a historically rural area that in recent years has experienced an increase in population and in the construction of new housing units, most of which are not connected to a centralized wastewater treatment system. Increasing water use has raised concerns about the effect of development on the available groundwater resources in the area. During 2011–12, the U.S. Geological Survey, in cooperation with Bernalillo County Public Works Natural Resource Services, used a water-budget approach to quantify the amount of potential groundwater recharge occurring from the domestic sewage (effluent) dosed to the sewage disposal field at two locations—sites A and B—in eastern Bernalillo County, N. Mex. The amount of effluent that is potentially available for groundwater recharge was determined as the mean daily volume of effluent dosed to the disposal field in excess of the mean daily volume of effluent loss from evapotranspiration from the disposal field.

  13. Study on the Variation of Groundwater Level under Time-varying Recharge

    Science.gov (United States)

    Wu, Ming-Chang; Hsieh, Ping-Cheng

    2017-04-01

    The slopes of the suburbs come to important areas by focusing on the work of soil and water conservation in recent years. The water table inside the aquifer is affected by rainfall, geology and topography, which will result in the change of groundwater discharge and water level. Currently, the way to obtain water table information is to set up the observation wells; however, owing to that the cost of equipment and the wells excavated is too expensive, we develop a mathematical model instead, which might help us to simulate the groundwater level variation. In this study, we will discuss the groundwater level change in a sloping unconfined aquifer with impermeable bottom under time-varying rainfall events. Referring to Child (1971), we employ the Boussinesq equation as the governing equation, and apply the General Integral Transforms Method (GITM) to analyzing the groundwater level after linearizing the Boussinesq equation. After comparing the solution with Verhoest & Troch (2000) and Bansal & Das (2010), we get satisfactory results. To sum up, we have presented an alternative approach to solve the linearized Boussinesq equation for the response of groundwater level in a sloping unconfined aquifer. The present analytical results combine the effect of bottom slope and the time-varying recharge pattern on the water table fluctuations. Owing to the limitation and difficulty of measuring the groundwater level directly, we develop such a mathematical model that we can predict or simulate the variation of groundwater level affected by any rainfall events in advance.

  14. Performance evaluation of a dual-flow recharge filter for improving groundwater quality.

    Science.gov (United States)

    Samuel, Manoj P; Senthilvel, S; Mathew, Abraham C

    2014-07-01

    A dual-flow multimedia stormwater filter integrated with a groundwater recharge system was developed and tested for hydraulic efficiency and pollutant removal efficiency. The influent stormwater first flows horizontally through the circular layers of planted grass and biofibers. Subsequently, the flow direction changes to a vertical direction so that water moves through layers of pebbles and sand and finally gets recharged to the deep aquifers. The media in the sequence of vegetative medium:biofiber to pebble:sand were filled in nine proportions and tested for the best performing combination. Three grass species, viz., Typha (Typha angustifolia), Vetiver (Chrysopogon zizanioides), and St. Augustine grass (Stenotaphrum secundatum), were tested as the best performing vegetative medium. The adsorption behavior of Coconut (Cocos nucifera) fiber, which was filled in the middle layer, was determined by a series of column and batch studies.The dual-flow filter showed an increasing trend in hydraulic efficiency with an increase in flowrate. The chemical removal efficiency of the recharge dual-flow filter was found to be very high in case of K+ (81.6%) and Na+ (77.55%). The pH normalizing efficiency and electrical conductivity reduction efficiency were also recorded as high. The average removal percentage of Ca2+ was moderate, while that of Mg2+ was very low. The filter proportions of 1:1 to 1:2 (plant:fiber to pebble:sand) showed a superior performance compared to all other proportions. Based on the estimated annual costs and returns, all the financial viability criteria (internal rate of return, net present value, and benefit-cost ratio) were found to be favorable and affordable to farmers in terms of investing in the developed filtration system.

  15. Estimate of regional groundwater recharge rate in the Central Haouz Plain, Morocco, using the chloride mass balance method and a geographical information system

    Science.gov (United States)

    Ait El Mekki, Ouassil; Laftouhi, Nour-Eddine; Hanich, Lahoucine

    2017-07-01

    Located in the extreme northwest of Africa, the Kingdom of Morocco is increasingly affected by drought. Much of the country is characterised by an arid to semi-arid climate and the demand for water is considerably higher than the supply, particularly on the Haouz Plain in the centre of the country. The expansion of agriculture and tourism, in addition to industrial development and mining, have exacerbated the stress on water supplies resulting in drought. It is therefore necessary to adopt careful management practices to preserve the sustainability of the water resources in this region. The aquifer recharge rate in the piedmont region that links the High Atlas and the Central Haouz Plain was estimated using the chloride mass balance hydrochemical method, which is based on the relationship between the chloride concentrations in groundwater and rainwater. The addition of a geographical information system made it possible to estimate the recharge rate over the whole 400 km2 of the study area. The results are presented in the form of a map showing the spatialized recharge rate, which ranges from 13 to 100 mm/year and the recharge percentage of the total rainfall varies from 3 to 25 % for the hydrological year 2011-2012. This approach will enable the validation of empirical models covering areas >6200 km2, such as the Haouz nappe.

  16. Spatial variability of the response to climate change in regional groundwater systems -- examples from simulations in the Deschutes Basin, Oregon

    Science.gov (United States)

    Waibel, Michael S.; Gannett, Marshall W.; Chang, Heejun; Hulbe, Christina L.

    2013-01-01

    We examine the spatial variability of the response of aquifer systems to climate change in and adjacent to the Cascade Range volcanic arc in the Deschutes Basin, Oregon using downscaled global climate model projections to drive surface hydrologic process and groundwater flow models. Projected warming over the 21st century is anticipated to shift the phase of precipitation toward more rain and less snow in mountainous areas in the Pacific Northwest, resulting in smaller winter snowpack and in a shift in the timing of runoff to earlier in the year. This will be accompanied by spatially variable changes in the timing of groundwater recharge. Analysis of historic climate and hydrologic data and modeling studies show that groundwater plays a key role in determining the response of stream systems to climate change. The spatial variability in the response of groundwater systems to climate change, particularly with regard to flow-system scale, however, has generally not been addressed in the literature. Here we simulate the hydrologic response to projected future climate to show that the response of groundwater systems can vary depending on the location and spatial scale of the flow systems and their aquifer characteristics. Mean annual recharge averaged over the basin does not change significantly between the 1980s and 2080s climate periods given the ensemble of global climate models and emission scenarios evaluated. There are, however, changes in the seasonality of groundwater recharge within the basin. Simulation results show that short-flow-path groundwater systems, such as those providing baseflow to many headwater streams, will likely have substantial changes in the timing of discharge in response changes in seasonality of recharge. Regional-scale aquifer systems with flow paths on the order of many tens of kilometers, in contrast, are much less affected by changes in seasonality of recharge. Flow systems at all spatial scales, however, are likely to reflect

  17. Application of Modflow in Groundwater Management and Evaluation of Artificial Recharge Project of Ab-barik Aquifer (Bam

    Directory of Open Access Journals (Sweden)

    Homayoun Katibeh

    2005-08-01

    Full Text Available This study is an attempt in groundwater modeling of Ab-barik aquifer (Bam, Iran, in order to asses the artificial recharge project and the future situation of the aquifer. Studies show that the discharge of the aquifer has exceeded the recharge, especially during the 1980-1990. The water table in March 1985 has dropped about 10m as compared with March 1973. Studies indicate that the drawdown of the free surface will continue in the future so that in March 2004, the drawdown will be about 18m as compared with the March 1973. Also it was found that despite the artificial recharge of the aquifer (started in 1996, the drawdown has been continuing. Modeling has showed that artificial recharge project has caused 12.6 mm3 recharge into the aquifer annually, during 1996-1999.

  18. Integrating a Linear Signal Model with Groundwater and Rainfall time-series on the Characteristic Identification of Groundwater Systems

    Science.gov (United States)

    Chen, Yu-Wen; Wang, Yetmen; Chang, Liang-Cheng

    2017-04-01

    Groundwater resources play a vital role on regional supply. To avoid irreversible environmental impact such as land subsidence, the characteristic identification of groundwater system is crucial before sustainable management of groundwater resource. This study proposes a signal process approach to identify the character of groundwater systems based on long-time hydrologic observations include groundwater level and rainfall. The study process contains two steps. First, a linear signal model (LSM) is constructed and calibrated to simulate the variation of underground hydrology based on the time series of groundwater levels and rainfall. The mass balance equation of the proposed LSM contains three major terms contain net rate of horizontal exchange, rate of rainfall recharge and rate of pumpage and four parameters are required to calibrate. Because reliable records of pumpage is rare, the time-variant groundwater amplitudes of daily frequency (P ) calculated by STFT are assumed as linear indicators of puamage instead of pumpage records. Time series obtained from 39 observation wells and 50 rainfall stations in and around the study area, Pintung Plain, are paired for model construction. Second, the well-calibrated parameters of the linear signal model can be used to interpret the characteristic of groundwater system. For example, the rainfall recharge coefficient (γ) means the transform ratio between rainfall intention and groundwater level raise. The area around the observation well with higher γ means that the saturated zone here is easily affected by rainfall events and the material of unsaturated zone might be gravel or coarse sand with high infiltration ratio. Considering the spatial distribution of γ, the values of γ decrease from the upstream to the downstream of major rivers and also are correlated to the spatial distribution of grain size of surface soil. Via the time-series of groundwater levels and rainfall, the well-calibrated parameters of LSM have

  19. Web-based global inventory of managed aquifer recharge applications

    NARCIS (Netherlands)

    Stefan, Catalin; Ansems, Nienke

    2017-01-01

    Managed aquifer recharge (MAR) is being successfully implemented worldwide for various purposes: to increase groundwater storage, improve water quality, restore groundwater levels, prevent salt water intrusion, manage water distribution systems, and enhance ecological benefits. To better understand

  20. Revised conceptualization of the North China Basin groundwater flow system: Groundwater age, heat and flow simulations

    Science.gov (United States)

    Cao, Guoliang; Han, Dongmei; Currell, Matthew J.; Zheng, Chunmiao

    2016-09-01

    Groundwater flow in deep sedimentary basins results from complex evolution processes on geological timescales. Groundwater flow systems conceptualized according to topography and/or groundwater table configuration generally assume a near-equilibrium state with the modern landscape. However, the time to reach such a steady state, and more generally the timescales of groundwater flow system evolution are key considerations for large sedimentary basins. This is true in the North China Basin (NCB), which has been studied for many years due to its importance as a groundwater supply. Despite many years of study, there remain contradictions between the generally accepted conceptual model of regional flow, and environmental tracer data. We seek to reconcile these contractions by conducting simulations of groundwater flow, age and heat transport in a three dimensional model, using an alternative conceptual model, based on geological, thermal, isotope and historical data. We infer flow patterns under modern hydraulic conditions using this new model and present the theoretical maximum groundwater ages under such a flow regime. The model results show that in contrast to previously accepted conceptualizations, most groundwater is discharged in the vicinity of the break-in-slope of topography at the boundary between the piedmont and central plain. Groundwater discharge to the ocean is in contrast small, and in general there are low rates of active flow in the eastern parts of the basin below the central and coastal plain. This conceptualization is more compatible with geochemical and geothermal data than the previous model. Simulated maximum groundwater ages of ∼1 Myrs below the central and coastal plain indicate that residual groundwater may be retained in the deep parts of the basin since being recharged during the last glacial period or earlier. The groundwater flow system has therefore probably not reached a new equilibrium state with modern-day hydraulic conditions. The

  1. Evaluation of geohydrologic framework, recharge estimates and ground-water flow of the Joshua Tree area, San Bernardino County, California

    Science.gov (United States)

    Nishikawa, Tracy; Izbicki, John A.; Hevesi, Joseph A.; Stamos, Christina L.; Martin, Peter

    2005-01-01

    Ground water historically has been the sole source of water supply for the community of Joshua Tree in the Joshua Tree ground-water subbasin of the Morongo ground-water basin in the southern Mojave Desert. The Joshua Basin Water District (JBWD) supplies water to the community from the underlying Joshua Tree ground-water subbasin. The JBWD is concerned with the long-term sustainability of the underlying aquifer. To help meet future demands, the JBWD plans to construct production wells in the adjacent Copper Mountain ground-water subbasin. As growth continues in the desert, there may be a need to import water to supplement the available ground-water resources. In order to manage the ground-water resources and to identify future mitigating measures, a thorough understanding of the ground-water system is needed. The purpose of this study was threefold: (1) improve the understanding of the geohydrologic framework of the Joshua Tree and Copper Mountain ground-water subbasins, (2) determine the distribution and quantity of recharge using field and numerical techniques, and (3) develop a ground-water flow model that can be used to help manage the water resources of the region. The geohydrologic framework was refined by collecting and interpreting water-level and water-quality data, geologic and electric logs, and gravity data. The water-bearing deposits in the Joshua Tree and Copper Mountain ground-water subbasins are Quarternary alluvial deposits and Tertiary sedimentary and volcanic deposits. The Quarternary alluvial deposits were divided into two aquifers (referred to as the 'upper' and the 'middle' alluvial aquifers), which are about 600 feet (ft) thick, and the Tertiary sedimentary and volcanic deposits were assigned to a single aquifer (referred to as the 'lower' aquifer), which is as thick as 1,500 ft. The ground-water quality of the Joshua Tree and Copper Mountain ground-water subbasins was defined by collecting 53 ground-water samples from 15 wells (10 in the

  2. Hydrogeochemical Investigation of Recharge Pathways to Intermediate and Regional Groundwater in Canon de Valle and Technical Area 16, Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Brady, Brendan W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-11-14

    In aquifers consisting of fractured or porous igneous rocks, as well as conglomerate and sandstone products of volcanic formations, silicate minerals actively dissolve and precipitate (Eby, 2004; Eriksson, 1985; Drever, 1982). Dissolution of hydrated volcanic glass is also known to influence the character of groundwater to which it is exposed (White et al., 1980). Hydrochemical evolution, within saturated zones of volcanic formations, is modeled here as a means to resolve the sources feeding a perched groundwater zone. By observation of solute mass balances in groundwater, together with rock chemistry, this study characterizes the chemical weathering processes active along recharge pathways in a mountain front system. Inverse mass balance modeling, which accounts for mass fluxes between solid phases and solution, is used to contrive sets of quantitative reactions that explain chemical variability of water between sampling points. Model results are used, together with chloride mass balance estimation, to evaluate subsurface mixing scenarios generated by further modeling. Final model simulations estimate contributions of mountain block and local recharge to various contaminated zones.

  3. Long-term increase in diffuse groundwater recharge following expansion of rainfed cultivation in the Sahel, West Africa

    Science.gov (United States)

    Ibrahim, Maïmouna; Favreau, Guillaume; Scanlon, Bridget R.; Seidel, Jean Luc; Le Coz, Mathieu; Demarty, Jérôme; Cappelaere, Bernard

    2014-09-01

    Rapid population growth in sub-Saharan West Africa and related cropland expansion were shown in some places to have increased focused recharge through ponds, raising the water table. To estimate changes in diffuse recharge, the water content and matric potential were monitored during 2009 and 2010, and modeling was performed using the Hydrus-1D code for two field sites in southwest Niger: (1) fallow land and (2) rainfed millet cropland. Monitoring results of the upper 10 m showed increased water content and matric potential to greater depth under rainfed cropland (>2.5 m) than under fallow land (≤1.0 m). Model simulations indicate that conversion from fallow land to rainfed cropland (1) increases vadose-zone water storage and (2) should increase drainage flux (˜25 mm year-1) at 10-m depth after a 30-60 year lag. Therefore, observed regional increases in groundwater storage may increasingly result from diffuse recharge, which could compensate, at least in part, groundwater withdrawal due to observed expansion in irrigated surfaces; and hence, contribute to mitigate food crises in the Sahel.

  4. Recharge sources and geochemical evolution of groundwater in the Quaternary aquifer at Atfih area, the northeastern Nile Valley, Egypt

    Science.gov (United States)

    El-Sayed, Salah Abdelwahab; Morsy, Samah M.; Zakaria, Khalid M.

    2018-06-01

    This study addresses the topic of recharge sources and evolution of groundwater in the Atfih area situated in the northeastern part of the Nile Valley, Egypt. Inventory of water wells and collection of groundwater and surface water samples have been achieved. Water samples are analyzed for major ions according to the American Society for Testing and Materials and for the environmental isotopes analysis (oxygen-18 and deuterium) by using a Triple Liquid Isotopic Water Analyzer (Los Gatos). The groundwater is available from the Quaternary aquifer formed mainly of graded sand and gravel interbedded with clay lenses. The hydrogeologic, hydrogeochemical and isotopic investigations indicate the hydrodynamic nature of the aquifer, where different flow paths, recharge sources and evolution mechanisms are distinguished. The directions of groundwater flow are from E, W and S directions suggesting the contribution from Nile River, the Eocene aquifer and the Nile basin, respectively. The groundwater altitudes range from 13 m (MSL) to 44 m (MSL). The hydraulic gradient varies between 0.025 and 0.0015. The groundwater is alkaline (pH > 7) and has salinity ranging from fresh to brackish water (TDS between 528 mg/l and 6070 mg/l). The observed wide range in the ionic composition and water types reflects the effect of different environmental and geological conditions through which the water has flowed. The isotopic compositions of groundwater samples vary between -14.13‰ and +23.56 for δD and between - 2.91‰ and +3.10 for δ18O. The isotopic data indicates that the Quaternary aquifer receive recharge from different sources including the Recent Nile water, surplus irrigation water, old Nile water before the construction of Aswan High Dam, surface runoff of local rains and Eocene aquifer. Evaporation, water rock interaction and mixing between different types of waters are the main processes in the groundwater evolution. Major suggestions are presented to develop the aquifer

  5. Using Isotope Methods to Assess Groundwater Recharge in Some Hydraulic Catchments in a Semiarid Region in Central Tunisia

    Energy Technology Data Exchange (ETDEWEB)

    Zouari, K.; Trabelsi, R.; Kacem, A. [Laboratory of Radio-Analysis and Environment, ENIS, Sfax (Tunisia)

    2013-07-15

    Water resource issues constitute a major concern in arid and semiarid areas in Tunisia. To meet rising demand for different human activities considerable importance is being given to improving the natural groundwater recharge by the installation of hydraulic catchments. In central Tunisia, numerous retention sites and dams have been built since 1990, for example, the el Ogla dam in the Nadhour-Saouaf basin. In order to determine the implication of these hill reservoirs on the hydrodynamic functioning and water quality of the aquifer system, hydrochemical (major elements) and isotopic methods have been employed. The interpretation of these results showed that the shallow aquifer is recharged mainly by surface water and water dam infiltration from the el Ogla and Sahel catchments. A tentative isotopic mass balance based on stable isotope contents leads to the quantification of the artificial recharge rate, which ranges between 42% and 86% of precipitation in the humid period. (author)

  6. Linking soil moisture balance and source-responsive models to estimate diffuse and preferential components of groundwater recharge

    Science.gov (United States)

    Cuthbert, M.O.; Mackay, R.; Nimmo, J.R.

    2012-01-01

    Results are presented of a detailed study into the vadose zone and shallow water table hydrodynamics of a field site in Shropshire, UK. A conceptual model is developed and tested using a range of numerical models, including a modified soil moisture balance model (SMBM) for estimating groundwater recharge in the presence of both diffuse and preferential flow components. Tensiometry reveals that the loamy sand topsoil wets up via macropore flow and subsequent redistribution of moisture into the soil matrix. Recharge does not occur until near-positive pressures are achieved at the top of the sandy glaciofluvial outwash material that underlies the topsoil, about 1 m above the water table. Once this occurs, very rapid water table rises follow. This threshold behaviour is attributed to the vertical discontinuity in the macropore system due to seasonal ploughing of the topsoil, and a lower permeability plough/iron pan restricting matrix flow between the topsoil and the lower outwash deposits. Although the wetting process in the topsoil is complex, a SMBM is shown to be effective in predicting the initiation of preferential flow from the base of the topsoil into the lower outwash horizon. The rapidity of the response at the water table and a water table rise during the summer period while flow gradients in the unsaturated profile were upward suggest that preferential flow is also occurring within the outwash deposits below the topsoil. A variation of the source-responsive model proposed by Nimmo (2010) is shown to reproduce the observed water table dynamics well in the lower outwash horizon when linked to a SMBM that quantifies the potential recharge from the topsoil. The results reveal new insights into preferential flow processes in cultivated soils and provide a useful and practical approach to accounting for preferential flow in studies of groundwater recharge estimation.

  7. Global depletion of groundwater resources

    NARCIS (Netherlands)

    Wada, Y.; Beek, L.P.H. van; van Kempen, C.M.; Reckman, J.W.T.M.; Vasak, S.; Bierkens, M.F.P.

    2010-01-01

    In regions with frequent water stress and large aquifer systems groundwater is often used as an additional water source. If groundwater abstraction exceeds the natural groundwater recharge for extensive areas and long times, overexploitation or persistent groundwater depletion occurs. Here we

  8. Death Valley regional groundwater flow system, Nevada and California-Hydrogeologic framework and transient groundwater flow model

    Science.gov (United States)

    Belcher, Wayne R.; Sweetkind, Donald S.

    2010-01-01

    A numerical three-dimensional (3D) transient groundwater flow model of the Death Valley region was developed by the U.S. Geological Survey for the U.S. Department of Energy programs at the Nevada Test Site and at Yucca Mountain, Nevada. Decades of study of aspects of the groundwater flow system and previous less extensive groundwater flow models were incorporated and reevaluated together with new data to provide greater detail for the complex, digital model. A 3D digital hydrogeologic framework model (HFM) was developed from digital elevation models, geologic maps, borehole information, geologic and hydrogeologic cross sections, and other 3D models to represent the geometry of the hydrogeologic units (HGUs). Structural features, such as faults and fractures, that affect groundwater flow also were added. The HFM represents Precambrian and Paleozoic crystalline and sedimentary rocks, Mesozoic sedimentary rocks, Mesozoic to Cenozoic intrusive rocks, Cenozoic volcanic tuffs and lavas, and late Cenozoic sedimentary deposits of the Death Valley regional groundwater flow system (DVRFS) region in 27 HGUs. Information from a series of investigations was compiled to conceptualize and quantify hydrologic components of the groundwater flow system within the DVRFS model domain and to provide hydraulic-property and head-observation data used in the calibration of the transient-flow model. These studies reevaluated natural groundwater discharge occurring through evapotranspiration (ET) and spring flow; the history of groundwater pumping from 1913 through 1998; groundwater recharge simulated as net infiltration; model boundary inflows and outflows based on regional hydraulic gradients and water budgets of surrounding areas; hydraulic conductivity and its relation to depth; and water levels appropriate for regional simulation of prepumped and pumped conditions within the DVRFS model domain. Simulation results appropriate for the regional extent and scale of the model were provided

  9. Monitoring and modeling infiltration–recharge dynamics of managed aquifer recharge with desalinated seawater

    OpenAIRE

    Ganot, Y.; Ganot, Y.; Holtzman, R.; Weisbrod, N.; Nitzan, I.; Katz, Y.; Kurtzman, D.

    2017-01-01

    We study the relation between surface infiltration and groundwater recharge during managed aquifer recharge (MAR) with desalinated seawater in an infiltration pond, at the Menashe site that overlies the northern part of the Israeli Coastal Aquifer. We monitor infiltration dynamics at multiple scales (up to the scale of the entire pond) by measuring the ponding depth, sediment water content and groundwater levels, using pressure sensors, single-ring infiltrometers, soil senso...

  10. Does localized recharge occur at a discharge area within the ground-water flow system of Yucca Mountain, Nevada?

    International Nuclear Information System (INIS)

    Czarnecki, J.B.; Kroitoru, L.; Ronen, D.; Magaritz, M.

    1992-01-01

    Studies done in 1984, at a central site on Franklin Lake playa (also known as Alkali Flat, a major discharge area of the ground-water flow system that includes Yucca Mountain, Nevada, the potential site of a high-level nuclear-waste repository) yield limited hydraulic-head and hydrochemical data from a 3-piezometer nest which indicated a slightly downward hydraulic gradient (-0.02) and decreasing concentration of dissolved solids with increasing depth. Hydraulic-head measurements in June, 1989 made at the piezometer nest showed a substantially larger downward gradient (-0.10) and a 0. 83-meter higher water level in the shallowest piezometer (3.29 meters deep), indicating the possibility of localized recharge. during the period of September-November, 1989, a multilevel sampler was used to obtain detailed hydrochemical profiles of the uppermost 1. 5 m of the saturated zone

  11. Optimal estimation of spatially variable recharge and transmissivity fields under steady-state groundwater flow. Part 1. Theory

    Science.gov (United States)

    Graham, Wendy D.; Tankersley, Claude D.

    1994-05-01

    Stochastic methods are used to analyze two-dimensional steady groundwater flow subject to spatially variable recharge and transmissivity. Approximate partial differential equations are developed for the covariances and cross-covariances between the random head, transmissivity and recharge fields. Closed-form solutions of these equations are obtained using Fourier transform techniques. The resulting covariances and cross-covariances can be incorporated into a Bayesian conditioning procedure which provides optimal estimates of the recharge, transmissivity and head fields given available measurements of any or all of these random fields. Results show that head measurements contain valuable information for estimating the random recharge field. However, when recharge is treated as a spatially variable random field, the value of head measurements for estimating the transmissivity field can be reduced considerably. In a companion paper, the method is applied to a case study of the Upper Floridan Aquifer in NE Florida.

  12. Use of multiple age tracers to estimate groundwater residence times and long-term recharge rates in arid southern Oman

    Science.gov (United States)

    Müller, Th.; Osenbrück, K.; Strauch, G.; Pavetich, S.; Al-Mashaikhi, K.-S.; Herb, C.; Merchel, S.; Rugel, G.; Aeschbach, W.; Sanford, Ward E.

    2016-01-01

    Multiple age tracers were measured to estimate groundwater residence times in the regional aquifer system underlying southwestern Oman. This area, known as the Najd, is one of the most arid areas in the world and is planned to be the main agricultural center of the Sultanate of Oman in the near future. The three isotopic age tracers 4He, 14C and 36Cl were measured in waters collected from wells along a line that extended roughly from the Dhofar Mountains near the Arabian Sea northward 400 km into the Empty Quarter of the Arabian Peninsula. The wells sampled were mostly open to the Umm Er Radhuma confined aquifer, although, some were completed in the mostly unconfined Rus aquifer. The combined results from the three tracers indicate the age of the confined groundwater is  100 ka in the central section north of the mountains, and up to and > one Ma in the Empty Quarter. The 14C data were used to help calibrate the 4He and 36Cl data. Mixing models suggest that long open boreholes north of the mountains compromise 14C-only interpretations there, in contrast to 4He and 36Cl calculations that are less sensitive to borehole mixing. Thus, only the latter two tracers from these more distant wells were considered reliable. In addition to the age tracers, δ2H and δ18O data suggest that seasonal monsoon and infrequent tropical cyclones are both substantial contributors to the recharge. The study highlights the advantages of using multiple chemical and isotopic data when estimating groundwater travel times and recharge rates, and differentiating recharge mechanisms.

  13. Design of Infiltration Well in Wetlands Area that Suitable for Giving Maximum Groundwater Recharge

    Directory of Open Access Journals (Sweden)

    Irfan Prasetia

    2016-02-01

    Full Text Available Growth in residential, industrial, and office  area,are significantly occurred in all city in Indonesia. Unfortunately, this is also caused more land that being covered by pavement and concrete in the cities. Realized or not it will disturb the availability of the groundwater and also lead to flooding in the rainy season. One of the effective solutions to solve this problem is by making sufficient numbers of infiltration well in the city, especially in the residential area. This research was conducted to analyze the ideal design of the infiltration well in the residential area. The design was made according to the equation by Sunjoto, which also refers to Indonesia standard (SNI No: 03- 2453-2002. The results show that the ideal dimension for the infiltration well is to use the radius of the well (R of 1.25 m. With the R of 1.25 will give a significant recharge to the groundwater as much as ≈ 2.400 liter. It is expected that this research encourage a development in the urban drainage systems which will consider the environment and the groundwater reservation for the balance of our ecosystem.

  14. Hydrochemistry and Isotope Hydrology for Groundwater Sustainability of the Coastal Multilayered Aquifer System (Zhanjiang, China

    Directory of Open Access Journals (Sweden)

    Pengpeng Zhou

    2017-01-01

    Full Text Available Groundwater sustainability has become a critical issue for Zhanjiang (China because of serious groundwater level drawdown induced by overexploitation of its coastal multilayered aquifer system. It is necessary to understand the origins, material sources, hydrochemical processes, and dynamics of the coastal groundwater in Zhanjiang to support its sustainable management. To this end, an integrated analysis of hydrochemical and isotopic data of 95 groundwater samples was conducted. Hydrochemical analysis shows that coastal groundwater is fresh; however, relatively high levels of Cl−, Mg2+, and total dissolved solid (TDS imply slight seawater mixing with coastal unconfined groundwater. Stable isotopes (δ18O and δ2H values reveal the recharge sources of groundwater in the multilayered aquifer system. The unconfined groundwater originates from local modern precipitation; the confined groundwater in mainland originates from modern precipitation in northwestern mountain area, and the confined groundwater in Donghai and Leizhou is sourced from rainfall recharge during an older period with a colder climate. Ionic relations demonstrate that silicate weathering, carbonate dissolutions, and cation exchange are the primary processes controlling the groundwater chemical composition. Declining trends of groundwater level and increasing trends of TDS of the confined groundwater in islands reveal the landward extending tendency of the freshwater-seawater mixing zone.

  15. Vegetation induced diel signal and its meaning in recharge and discharge regions

    Science.gov (United States)

    Gribovszki, Zoltán; Tóth, Tibor; Csáfordi, Péter; Szabó, András; Móricz, Norbert; Kalicz, Péter

    2017-04-01

    Afforestation, promoted by the European Union is planned in Hungary in the next decades. One of the most important region for afforestation is the Hungarian Great Plain where the precipitation is far below potential ET so forests can not survive without significant water uptake from shallow groundwater. Diel fluctuations of hydrological variables (e.g., soil moisture, shallow groundwater level, streamflow rate) are rarely investigated in the hydrologic literature although these short-term fluctuations may incorporate useful information (like groundwater uptake) about hydro-ecological systems in shallow groundwater areas. Vegetation induced diel fluctuations are rarely compared under varying hydrologic conditions (such as recharge and discharge zones). In this study, the data of soil moisture and shallow groundwater monitoring under different surface covers (forest and neighboring agricultural plots) in discharge and recharge regions were analyzed to gain a better understanding of the vegetation hydrological impact or water uptake in changing climate. The pilot areas of the study are located in Hungarian Great Plain and in Western Hungary. The water table under the forest displayed a typical night-time recovery in the discharge region, indicating a significant groundwater supply. Certainly, the root system of the forest was able to tap the groundwater in depths measuring a few metres, while the shallower roots of the herbaceous vegetation generally did not reach the groundwater reservoir at these depths. In the recharge zone the water table under the forest showed step-like diel pattern that refer to a lack of additional groundwater supply from below. The low groundwater evapotranspiration of the forest in the recharge zone was due to the lack of the groundwater supply in the recharge area. Similar patterns can be detected in the soil moisture of recharge and discharge zones as well. Our results suggest that local estimations of groundwater evapotranspiration from

  16. Monitoring and modeling infiltration-recharge dynamics of managed aquifer recharge with desalinated seawater

    OpenAIRE

    Ganot, Yonatan; Holtzman, Ran; Weisbrod, Noam; Nitzan, Ido; Katz, Yoram; Kurtzman, Daniel

    2016-01-01

    We study the relation between surface infiltration and groundwater recharge during managed aquifer recharge (MAR) with desalinated seawater in an infiltration pond, at the Menashe site that overlies the northern part of the Israeli Coastal Aquifer. We monitor infiltration dynamics at multiple scales (up to the scale of the entire pond) by measuring the ponding depth, sediment water content and groundwater levels, using pressure sensors, single-ring infiltrometers, soil sensors and observation...

  17. Characterization of recharge processes in shallow and deeper aquifers using isotopic signatures and geochemical behavior of groundwater in an arsenic-enriched part of the Ganga Plain

    International Nuclear Information System (INIS)

    Saha, Dipankar; Sinha, U.K.; Dwivedi, S.N.

    2011-01-01

    Research highlights: → Sub-regional scale aquifers delineated in arsenic-enriched belt in the Ganga Plain. Isotopic fingerprint of the groundwater, from arsenic-enriched and arsenic-safe aquifers established for the first time in the Ganga Plain. → Recharge processes and the water provenances of vertically separated Quaternary aquifers have been established. → Mean residence time of groundwater in the deeper aquifers has been worked out using C-14 isotope. → Water from the deeper aquifer has been correlated with the paleoclimatic model of the Middle Ganga Plain (Mid-Ganga Basin) for 6-2 ka. - Abstract: Arsenic concentrations in groundwater extracted from shallow aquifers in some areas of the Ganga Plain in the states of Bihar and Uttar Pradesh, exceed 50 μg L -1 and locally reach levels in the 400 μg L -1 range. The study covered 535 km 2 of active flood plain of the River Ganga, in Bihar where a two-tier aquifer system has been delineated in a multi-cyclic sequence of Quaternary sand, clay, sandy clay and silty clay all ≤∼250 m below ground surface. The research used isotopic signatures (δ 18 O, δ 2 Η, 3 H, 14 C) and major chemical constituents (HCO 3 - ,SO 4 2- ,NO 3 - ,Cl - ,Ca 2+ ,Mg 2+ ,Na + ,K + ,As total ) of groundwater to understand the recharge processes and groundwater circulation in the aquifers. Values of δ 18 O and δ 2 Η combined with 3 H data indicate that the recharge to the As-enriched top 40 m of the deposits is modern ( -1 ) is hydrologically isolated from the upper aquifer and is characterized by lower 14 C concentration and lower (more negative) δ 18 O values. Groundwater in the lower aquifer is ∼3 ka old, occurs under semi-confined to confined conditions, with hydrostatic head at 1.10 m above the head of the upper aquifer during the pre-monsoon. The recharge areas of the lower aquifer lies in Pleistocene deposits in basin margin areas with the exposed Vindhyan System, at about 55 km south of the area.

  18. Potential Groundwater Recharge from the Infiltration of Surface Runoff in Cold and Dry Creeks, Phase 2

    International Nuclear Information System (INIS)

    Waichler, Scott R.

    2005-01-01

    Runoff from Cold and Dry Creeks may provide an important source of groundwater recharge on the Hanford Site. This report presents estimates of total volume and distribution of such recharge from extreme precipitation events. Estimates were derived using a simple approach that combined the Soil Conservation Service curve number runoff method and an exponential-decay channel infiltration model. Fifteen-minute streamflow data from four gaging stations, and hourly precipitation data from one climate station, were used to compute curve numbers and calibrate the infiltration model. All data were from several storms occurring during January 1995. Design storm precipitation depths ranging from 1.6 to 2.7 inches were applied with computed curve numbers to produce total runoff/recharge of 7,700 to 15,900 ac-ft, or approximately 10 times the average annual rate from this recharge source as determined in a previous study. Approximately two-thirds of the simulated recharge occurred in the lower stream reaches contained in the broad alluvial valley that parallels State Highway 240 near the Hanford 200 Area

  19. Potential Groundwater Recharge from the Infiltration of Surface Runoff in Cold and Dry Creeks, Phase 2

    Energy Technology Data Exchange (ETDEWEB)

    Waichler, Scott R.

    2005-12-13

    Runoff from Cold and Dry Creeks may provide an important source of groundwater recharge on the Hanford Site. This report presents estimates of total volume and distribution of such recharge from extreme precipitation events. Estimates were derived using a simple approach that combined the Soil Conservation Service curve number runoff method and an exponential-decay channel infiltration model. Fifteen-minute streamflow data from four gaging stations, and hourly precipitation data from one climate station, were used to compute curve numbers and calibrate the infiltration model. All data were from several storms occurring during January 1995. Design storm precipitation depths ranging from 1.6 to 2.7 inches were applied with computed curve numbers to produce total runoff/recharge of 7,700 to 15,900 ac-ft, or approximately 10 times the average annual rate from this recharge source as determined in a previous study. Approximately two-thirds of the simulated recharge occurred in the lower stream reaches contained in the broad alluvial valley that parallels State Highway 240 near the Hanford 200 Area.

  20. Downstream of downtown: urban wastewater as groundwater recharge

    Science.gov (United States)

    Foster, S. S. D.; Chilton, P. J.

    Wastewater infiltration is often a major component of overall recharge to aquifers around urban areas, especially in more arid climates. Despite this, such recharge still represents only an incidental (or even accidental) byproduct of various current practices of sewage effluent handling and wastewater reuse. This topic is reviewed through reference to certain areas of detailed field research, with pragmatic approaches being identified to reduce the groundwater pollution hazard of these practices whilst attempting to retain their groundwater resource benefit. Since urban sewage effluent is probably the only `natural resource' whose global availability is steadily increasing, the socioeconomic importance of this topic for rapidly developing urban centres in the more arid parts of Asia, Africa, Latin America and the Middle East will be apparent. L'infiltration des eaux usées est souvent la composante essentielle de toute la recharge des aquifères des zones urbaines, particulièrement sous les climats les plus arides. Malgré cela, une telle recharge ne constitue encore qu'un sous-produit incident, ou même accidentel, de pratiques courantes variées du traitement de rejets d'égouts et de réutilisation d'eaux usées. Ce sujet est passé en revue en se référant à certaines régions étudiées en détail, par des approches pragmatiques reconnues pour permettre de réduire les risques de pollution des nappes dues à ces pratiques tout en permettant d'en tirer profit pour leur ressource en eau souterraine. Puisque les effluents d'égouts urbains sont probablement la seule « ressource naturelle » dont la disponibilité globale va croissant constamment, l'importance socio-économique de ce sujet est évidente pour les centres urbains à développement rapide de l'Asie, de l'Afrique, de l'Amérique latine et du Moyen-Orient. La infiltración de aguas residuales es a menudo un componente principal de la recarga total en acuíferos ubicados en torno a zonas urbanas

  1. Estimation of potential rainfall recharge in the pothwar area

    International Nuclear Information System (INIS)

    Afzal, M.; Yaseen, M.

    2015-01-01

    Groundwater recharge is complex phenomenon to understand and describe because it cannot be seen with open eyes. We have to depend some theoretical assumptions to understand this complicated hidden natural underground water movement process. There are many factors affecting and controlling the water movement in soil profile. Groundwater use in district chakwal is of a fundamental importance to meet the rapidly expanding drinking and agricultural water requirements. The man factors contributing to groundwater recharge in chakwal are rainfall, evapotranspiration and geology. due to the semi arid climatic conditions of the area, this resource is almost the only key to economic development. There are a number of dug wells in the area where water is getting stored during rainy season. source and processes of recharge in humid areas are different compared with semi-arid areas. Due to the main resource of available water in the area, the potential groundwater recharge estimation could be good exercise to visulize the amount of rainwater entering the ground. For groundwater recharge estimation there are a number of simple and advanced techniques available. In the present study simple methods were used to estimate potential recharge due to available limited resources. Rainfall runoff, gravimetric and water table fluctuation methods were used to quantify rainfall recharge during the monsoon season. The average potential recharge estimated was 60% of the rainfall of 148 mm. Rainfall runoff and gravimetric methods were found to be comparable for short period potential recharge estimation while water table fluctuation method gives actual recharge and require longer period data. Potential recharge values were higher for area having grassland type vegetation and low for area covering shrubs and tick vegetation. (author)

  2. The artificial recharge as a tool for the water resources management: case of the aquifer recharge system of Geneva (Switzerland); La recarga artificial de acuifero como ayuda a la gestion de los recursos hidricos; el ejemplo del sistema de Ginebra (Suiza)

    Energy Technology Data Exchange (ETDEWEB)

    Cobos, G. de los

    2009-07-01

    The drinking water supply for the Geneva area comes partly (80%) from the lake Geneva and partly (20%) from a large transboundary aquifer called Genevois aquifer. During the 70's, over pumping lowered the groundwater level by more than 7m. Artificial recharge has been carried out from the Arve river into the Genevois aquifer in order to maintain the groundwater level and enable water resources management. Located near the Arve river, this artificial recharge plant started its activity in 1980. For the last almost 30 years the artificial recharge system of Geneva has brought over 230 hm{sup 3} of treated water into the Genevois aquifer. The impacts of the recharge on the Genevois aquifer and on the aquifer management are described in this paper. (Author) 20 refs.

  3. Characterization of the shallow groundwater system in an alpine watershed: Handcart Gulch, Colorado, USA

    Science.gov (United States)

    Kahn, Katherine G.; Ge, Shemin; Caine, Jonathan S.; Manning, A.

    2008-01-01

    Water-table elevation measurements and aquifer parameter estimates are rare in alpine settings because few wells exist in these environments. Alpine groundwater systems may be a primary source of recharge to regional groundwater flow systems. Handcart Gulch is an alpine watershed in Colorado, USA comprised of highly fractured Proterozoic metamorphic and igneous rocks with wells completed to various depths. Primary study objectives include determining hydrologic properties of shallow bedrock and surficial materials, developing a watershed water budget, and testing the consistency of measured hydrologic properties and water budget by constructing a simple model incorporating groundwater and surface water for water year 2005. Water enters the study area as precipitation and exits as discharge in the trunk stream or potential recharge for the deeper aquifer. Surficial infiltration rates ranged from 0.1-6.2??0-5 m/s. Discharge was estimated at 1.28??10-3 km3. Numerical modeling analysis of single-well aquifer tests predicted lower specific storage in crystalline bedrock than in ferricrete and colluvial material (6.7??10-5-2.10??0-3 l/m). Hydraulic conductivity in crystalline bedrock was significantly lower than in colluvial and alluvial material (4.3??10-9 -2.0??10-4 m/s). Water budget results suggest that during normal precipitation and temperatures water is available to recharge the deeper groundwater flow system. ?? Springer-Verlag 2007.

  4. PEMETAAN DATA RECHARGE AIR TANAH DI KABUPATEN SLEMAN BERDASARKAN DATA CURAH HUJAN

    Directory of Open Access Journals (Sweden)

    Bambang Yuwono

    2017-01-01

    The method used in this research is the Water Balance (keseimbangan airmethod. This method is based on any incoming rain water will be equal to the output evapotranspiration and runoff hereinafter this method is applied in the application. Factors affecting groundwater recharge the water balance method is precipitation, evapotranspiration and run off. Information og groundwater recharge is also displayed on the map using Google Map function are related to the database system to produce informative mapsCalculation of groundwater recharge is applied to the daily rainfall data input into the application which then included in the water balance equation method so it can be easy to determine the value of groundwater recharge. Groundwater recharge information can be displayed in the form of mapping, making them easier to understand visually.Based on testing, the highest recharge results of this research on the Kemput station is 1119,5 mm/year with rainfall of 2750 mm/year. Seyegan and Bronggang station is 1026,25 mm/year with rainfall of 2625 mm/year. Angin-angin and Prumpung station is 933 mm/year with rainfall of 2500 mm/year. Beran and Gemawang station is 839.5 mm/year with rainfall of 2375 mm/year. Plataran station is 808.42 mm/year with rainfall of 2333 mm/year. Godean station is 699.5 mm/year with rainfall of 2187 mm/year and the lowest at Tirto Tanjungand Santan stastion 560 mm / year with rainfall of 2000 mm / year.

  5. Trajectory analysis of land use and land cover maps to improve spatial-temporal patterns, and impact assessment on groundwater recharge

    Science.gov (United States)

    Zomlot, Z.; Verbeiren, B.; Huysmans, M.; Batelaan, O.

    2017-11-01

    Land use/land cover (LULC) change is a consequence of human-induced global environmental change. It is also considered one of the major factors affecting groundwater recharge. Uncertainties and inconsistencies in LULC maps are one of the difficulties that LULC timeseries analysis face and which have a significant effect on hydrological impact analysis. Therefore, an accuracy assessment approach of LULC timeseries is needed for a more reliable hydrological analysis and prediction. The objective of this paper is to assess the impact of land use uncertainty and to improve the accuracy of a timeseries of CORINE (coordination of information on the environment) land cover maps by using a new approach of identifying spatial-temporal LULC change trajectories as a pre-processing tool. This ensures consistency of model input when dealing with land-use dynamics and as such improves the accuracy of land use maps and consequently groundwater recharge estimation. As a case study the impact of consistent land use changes from 1990 until 2013 on groundwater recharge for the Flanders-Brussels region is assessed. The change trajectory analysis successfully assigned a rational trajectory to 99% of all pixels. The methodology is shown to be powerful in correcting interpretation inconsistencies and overestimation errors in CORINE land cover maps. The overall kappa (cell-by-cell map comparison) improved from 0.6 to 0.8 and from 0.2 to 0.7 for forest and pasture land use classes respectively. The study shows that the inconsistencies in the land use maps introduce uncertainty in groundwater recharge estimation in a range of 10-30%. The analysis showed that during the period of 1990-2013 the LULC changes were mainly driven by urban expansion. The results show that the resolution at which the spatial analysis is performed is important; the recharge differences using original and corrected CORINE land cover maps increase considerably with increasing spatial resolution. This study indicates

  6. Residence Times in Central Valley Aquifers Recharged by Dammed Rivers

    Science.gov (United States)

    Loustale, M.; Paukert Vankeuren, A. N.; Visser, A.

    2017-12-01

    Groundwater is a vital resource for California, providing between 30-60% of the state's water supply. Recent emphasis on groundwater sustainability has induced a push to characterize recharge rates and residence times for high priority aquifers, including most aquifers in California's Central Valley. Flows in almost all rivers from the western Sierra to the Central Valley are controlled by dams, altering natural flow patterns and recharge to local aquifers. In eastern Sacramento, unconfined and confined shallow aquifers (depth recharged by a losing reach of the Lower American River, despite the presence of levees with slurry cut-off walls.1 Flow in the Lower American River is controlled through the operation of the Folsom and Nimbus Dams, with a minimum flow of 500 cfs. Water table elevation in wells in close proximity to the river are compared to river stage to determine the effect of river stage on groundwater recharge rates. Additionally, Tritium-3Helium dates and stable isotopes (∂18O and ∂2H) have been measured in monitoring wells 200- 2400 ft lateral distance from the river, and depths of 25 -225 feet BGS. Variation in groundwater age in the vertical and horizontal directions are used to determine groundwater flow path and velocity. These data are then used to calculate residence time of groundwater in the unconfined and confined aquifer systems for the Central Valley in eastern Sacramento. Applying groundwater age tracers can benefit future compliance metrics of the California Sustainable Groundwater Resources Act (SGMA), by quantifying river seepage rates and impacts of groundwater management on surface water resources. 1Moran et al., UCRL-TR-203258, 2004.

  7. Implications of deep drainage through saline clay for groundwater recharge and sustainable cropping in a semi-arid catchment, Australia

    Science.gov (United States)

    Timms, W. A.; Young, R. R.; Huth, N.

    2012-04-01

    The magnitude and timing of deep drainage and salt leaching through clay soils is a critical issue for dryland agriculture in semi-arid regions (2000 mm yr-1) such as parts of Australia's Murray-Darling Basin (MDB). In this rare study, hydrogeological measurements and estimations of the historic water balance of crops grown on overlying Grey Vertosols were combined to estimate the contribution of deep drainage below crop roots to recharge and salinization of shallow groundwater. Soil sampling at two sites on the alluvial flood plain of the Lower Namoi catchment revealed significant peaks in chloride concentrations at 0.8-1.2 m depth under perennial vegetation and at 2.0-2.5 m depth under continuous cropping indicating deep drainage and salt leaching since conversion to cropping. Total salt loads of 91-229 t ha-1 NaCl equivalent were measured for perennial vegetation and cropping, with salinity to ≥ 10 m depth that was not detected by shallow soil surveys. Groundwater salinity varied spatially from 910 to 2430 mS m-1 at 21 to 37 m depth (N = 5), whereas deeper groundwater was less saline (290 mS m-1) with use restricted to livestock and rural domestic supplies in this area. The Agricultural Production Systems Simulator (APSIM) software package predicted deep drainage of 3.3-9.5 mm yr-1 (0.7-2.1% rainfall) based on site records of grain yields, rainfall, salt leaching and soil properties. Predicted deep drainage was highly episodic, dependent on rainfall and antecedent soil water content, and over a 39 yr period was restricted mainly to the record wet winter of 1998. During the study period, groundwater levels were unresponsive to major rainfall events (70 and 190 mm total), and most piezometers at about 18 m depth remained dry. In this area, at this time, recharge appears to be negligible due to low rainfall and large potential evapotranspiration, transient hydrological conditions after changes in land use and a thick clay dominated vadose zone. This is in

  8. Groundwater recharge ages in the eastern nile delta based on environmental tritium

    International Nuclear Information System (INIS)

    Hamza, M.S.; Aly, A.I.M.; Swailem, F.M.; Nada, A.

    1986-01-01

    The results of the tritium composition of groundwater from eastern Nile delta is presented and compared with the tritium content of the nile according to a given model. A contour map of isoline of tritium in the area was drawn. The decrease of tritium content values in the direction from southwest to northeast was attributed to salt water intrusion. The clustered tritium isoline could be due to local geophysical structures or mixing with other water of older recharge (paleowater).2 fig.,1 tab

  9. Application of the rainfall infiltration breakthrough (RIB) model for groundwater recharge estimation in west coastal South Africa

    CSIR Research Space (South Africa)

    Sun, X

    2013-04-01

    Full Text Available level fluctuations (WLF) on a monthly basis was proposed in the rainfall infiltration breakthrough (RIB) model for the purpose of groundwater recharge estimation. In this paper, the physical meaning of parameters in the CRD and previous RIB models...

  10. Natural Recharge to the Unconfined Aquifer System on the Hanford Site from the Greater Cold Creek Watershed: Progress Report 2004

    Energy Technology Data Exchange (ETDEWEB)

    Waichler, Scott R.; Wigmosta, Mark S.; Coleman, Andre M.

    2004-09-14

    Movement of contaminants in groundwater at the Hanford Site is heavily dependent on recharge to the unconfined aquifer. As the effects of past artificial discharges dissipate, the water table is expected to return to more natural conditions, and natural recharge will become the driving force when evaluating future groundwater flow conditions and related contaminant transport. Previous work on the relationship of natural recharge to groundwater movement at the Hanford Site has focused on direct recharge from infiltrating rainfall and snowmelt within the area represented by the Sitewide Groundwater Model (SGM) domain. However, part of the groundwater recharge at Hanford is provided by flow from Greater Cold Creek watershed (GCC), a large drainage area on the western boundary of the Hanford Site that includes Cold Creek Valley, Dry Creek Valley, and the Hanford side of Rattlesnake Mountain. This study was undertaken to estimate the recharge from GCC, which is believed to enter the unconfined aquifer as both infiltrating streamflow and shallow subsurface flow. To estimate recharge, the Distributed Hydrology-Soil-Vegetation Model (DHSVM) was used to simulate a detailed water balance of GCC from 1956 to 2001 at a spatial resolution of 200~m and a temporal resolution of one hour. For estimating natural recharge to Hanford from watersheds along its western and southwestern boundaries, the most important aspects that need to be considered are 1)~distribution and relative magnitude of precipitation and evapotranspiration over the watershed, 2)~streamflow generation at upper elevations and infiltration at lower elevations during rare runoff events, and 3)~permeability of the basalt bedrock surface underlying the soil mantle.

  11. Groundwater recharge assessment at local and episodic scale in a soil mantled perched karst aquifer in southern Italy

    Science.gov (United States)

    Allocca, V.; De Vita, P.; Manna, F.; Nimmo, John R.

    2015-01-01

    Groundwater recharge assessment of karst aquifers, at various spatial and temporal scales, is a major scientific topic of current importance, since these aquifers play an essential role for both socio-economic development and fluvial ecosystems.

  12. Groundwater recharge and flow on Montserrat, West Indies: Insights from groundwater dating

    Directory of Open Access Journals (Sweden)

    Brioch Hemmings

    2015-09-01

    New hydrological insights: δ2H and δ18O analysis indicates uniform recharge elevations for groundwaters on Montserrat. CFC-11 and CFC-12 analysis reveals age differences between isotopically similar, high elevation springs and low elevation aquifer waters. Low CFC concentrations within a confined low elevation aquifer suggest water ages of ∼45 years. High CFC concentrations in the northern and western springs are explained by rapid infiltration of cool (high CFC concentration rainfall into saturated compartments, with flow through the vadose zone to the phreatic zone dominated by compartment flow. Lower CFC concentrations in a number of aligned warmer springs suggest a contribution from older, warmer waters from depth. Temperatures and CFC concentrations indicate older component supply rates of up to 8 L/s to the highest yielding spring on Centre Hills, with contributions of up to 75% in the warmest spring waters.

  13. Hydrogeochemical characterization of Bacolod City groundwater system

    International Nuclear Information System (INIS)

    Sucgang, Raymond J.; Almoneda, Rosalina; Fernandez, Lourdes; Castaneda, Soledad S.; Gemora, Jenelyn Y.; Desengano, Daisy; Lim, Fatima

    2007-01-01

    Groundwater is constantly being recycled and replenished by rainfall. However, because of the uneven distribution of rain and the heavy use of water in certain areas, some regions are experiencing undue water shortage. Changes in land use, population growth, and economic development in the Bacolod City region, can result in an increase in water demand and the generation of additional pollution sources. To delineate the ground water recharge area for Bacolod City and at the same time, assess the vulnerability of the aquifer to pollution, water samples were collected in an attempt to relate chemical variations in ground water to the underlying differences in geology, availability and mechanism of recharge, and to define the natural versus anthropogenic influences in the groundwater system. Measurements of field data such as pH, conductivity, temperature and alkalinity were made. Several geochemical processes are recognized in the chemistry of the Bacolod aquifer system. The most important processes are: water-bedrock interaction, dissolution of connate halites , and seawater intrusion. Simple mass balance modeling shows that the feasible source of active recharge aside from direct precipitation, is infiltration from the Loygoy river. Rivers and tributaries transport water originated as precipitation falling at higher elevations. The ground water in Bacolod City is predominantly of the Ca-Mg-HCO 3 type. Recharge becomes sodium dominated along its path, indicating a slow but active mechanism. The ground water near the coasts is brackish due to sea water infiltration. The possible presence of connate halites lying in the deep aquifers is also indicated. The information generated, when used in conjunction with isotopic techniques, will be important in the choice of sites for pumping stations and in the knowledge of the extent of potential pollution of ground water from streams/reservoirs. (author)

  14. In-situ arsenic removal during groundwater recharge through unsaturated alluvium

    Science.gov (United States)

    O'Leary, David; Izbicki, John; T.J. Kim,; Clark Ajawani,; Suarez, Donald; Barnes, Thomas; Thomas Kulp,; Burgess, Matthew K.; Tseng, Iwen

    2015-01-01

    OBJECTIVES The purpose of this study was to determine the feasibility and sustainability of in-situ removal of arsenic from water infiltrated through unsaturated alluvium. BACKGROUND Arsenic is naturally present in aquifers throughout the southwestern United States and elsewhere. In January 2006, the U.S. Environmental Protection Agency (EPA) lowered the Maximum Contaminant Level (MCL) for arsenic from 50 to 10 micrograms per liter (g/L). This raised concerns about naturally-occurring arsenic in groundwater. Although commercially available systems using sorbent iron or aluminum oxide resins are available to treat high-arsenic water, these systems are expensive to build and operate, and may generate hazardous waste. Iron and aluminum oxides occur naturally on the surfaces of mineral grains that compose alluvial aquifers. In areas where alluvial deposits are unsaturated, these oxides may sorb arsenic in the same manner as commercial resins, potentially providing an effective low-cost alternative to commercially engineered treatment systems. APPROACH The Antelope Valley within the Mojave Desert of southern California contains a shallow water-table aquifer with arsenic concentrations of 5 g/L, and a deeper aquifer with arsenic concentrations of 30 g/L. Water was pumped from the deep aquifer into a pond and infiltrated through an 80 m-thick unsaturated zone as part of field-scale and laboratory experiments to treat high-arsenic groundwater and recharge the shallow water table aquifer at the site. The field-scale recharge experiment included the following steps: 1) construction of a recharge pond 2) test drilling for sample collection and instrument installation adjacent to the pond 3) monitoring downward migration of water infiltrated from the pond 4) monitoring changes in selected trace-element concentrations as water infiltrated through the unsaturated zone Data from instruments within the borehole adjacent to the pond were supplemented with borehole and

  15. Death Valley regional ground-water flow system, Nevada and California -- hydrogeologic framework and transient ground-water flow model

    Science.gov (United States)

    Belcher, Wayne R.

    2004-01-01

    A numerical three-dimensional (3D) transient ground-water flow model of the Death Valley region was developed by the U.S. Geological Survey for the U.S. Department of Energy programs at the Nevada Test Site and at Yucca Mountain, Nevada. Decades of study of aspects of the ground-water flow system and previous less extensive ground-water flow models were incorporated and reevaluated together with new data to provide greater detail for the complex, digital model. A 3D digital hydrogeologic framework model (HFM) was developed from digital elevation models, geologic maps, borehole information, geologic and hydrogeologic cross sections, and other 3D models to represent the geometry of the hydrogeologic units (HGUs). Structural features, such as faults and fractures, that affect ground-water flow also were added. The HFM represents Precambrian and Paleozoic crystalline and sedimentary rocks, Mesozoic sedimentary rocks, Mesozoic to Cenozoic intrusive rocks, Cenozoic volcanic tuffs and lavas, and late Cenozoic sedimentary deposits of the Death Valley Regional Ground-Water Flow System (DVRFS) region in 27 HGUs. Information from a series of investigations was compiled to conceptualize and quantify hydrologic components of the ground-water flow system within the DVRFS model domain and to provide hydraulic-property and head-observation data used in the calibration of the transient-flow model. These studies reevaluated natural ground-water discharge occurring through evapotranspiration and spring flow; the history of ground-water pumping from 1913 through 1998; ground-water recharge simulated as net infiltration; model boundary inflows and outflows based on regional hydraulic gradients and water budgets of surrounding areas; hydraulic conductivity and its relation to depth; and water levels appropriate for regional simulation of prepumped and pumped conditions within the DVRFS model domain. Simulation results appropriate for the regional extent and scale of the model were

  16. Natural recharge of groundwater captured in the hilly area of Kinshasa: Hydrochemical and isotopic approaches

    International Nuclear Information System (INIS)

    Mabiala, M.P.; Nlandu, W.J.; Ndembo, L.J.

    2005-01-01

    The stable isotopic content of daily precipitation sampled at Mount Amba (CGEA) shows large variations principally due to climatic conditions during rain events and to the type of air masses, which generaed the precipitation. The isotopic values of groundwater suggest, throughout the study zone, a rapid and easy recharge of the aquifers by direct infiltration precipitation. In some places, isotopic enrichment content could be attributed to evaporation processes during precipation. Groundwater is generally of chloride and sodium type. They are chemically good for drinking water, but localised high concentrations in nitrates indicate a risk of pollution of the aquifer.

  17. Groundwater recharge studies using isotope-chemical techniques in wadi gharandal, sinai peninsula(E G))

    International Nuclear Information System (INIS)

    Awad, M.A.A.; Salem, W.M.; Ezzeldin

    1999-01-01

    Wadi Gharandal lies on southwestern part of sinai peninsula with its outlets into the Gulf of suez. Eight groundwater samples were collected from quaternary aquifer in wadi gharandal to identify the sources of replenishment and evaluation of its water quality. The variation in chemical composition of water samples is due to water-rock interaction and the effect of sea spray. The distribution of chemical species in the examined groundwater samples is controlled by geography and climate conditions prevailing in the area of study. The salinity increase towards the gulf of suez. The isotopic data indicate that precipitation and floods are considered to be the main sources of recharge in this area. The investigated groundwater samples are found to be suitable for irrigation purposes based on sodium adsorption ratio (SAR) and unsuitable for domestic usages due to high salinity and hardness values

  18. Determining flow, recharge, and vadose zone drainage in an unconfined aquifer from groundwater strontium isotope measurements, Pasco Basin, WA

    International Nuclear Information System (INIS)

    2004-01-01

    Strontium isotope compositions (87Sr/86Sr) measured in groundwater samples from 273 wells in the Pasco Basin unconfined aquifer below the Hanford Site show large and systematic variations that provide constraints on groundwater recharge, weathering rates of the aquifer host rocks, communication between unconfined and deeper confined aquifers, and vadose zone-groundwater interaction. The impact of millions of cubic meters of wastewater discharged to the vadose zone (103-105 times higher than ambient drainage) shows up strikingly on maps of groundwater 87Sr/86Sr. Extensive access through the many groundwater monitoring wells at the site allows for an unprecedented opportunity to evaluate the strontium geochemistry of a major aquifer, hosted primarily in unconsolidated sediments, and relate it to both long term properties and recent disturbances. Groundwater 87Sr/86Sr increases systematically from 0.707 to 0.712 from west to east across the Hanford Site, in the general direction of groundwater flow, as a result of addition of Sr from the weathering of aquifer sediments and from diffuse drainage through the vadose zone. The lower 87Sr/86Sr groundwater reflects recharge waters that have acquired Sr from Columbia River Basalts. Based on a steady-state model of Sr reactive transport and drainage, there is an average natural drainage flux of 0-1.4 mm/yr near the western margin of the Hanford Site, and ambient drainage may be up to 30 mm/yr in the center of the site assuming an average bulk rock weathering rate of 10-7.5 g/g/yr

  19. Assessing the efficiency of a coastal Managed Aquifer Recharge (MAR) system in Cyprus.

    Science.gov (United States)

    Tzoraki, Ourania; Dokou, Zoi; Christodoulou, George; Gaganis, Petros; Karatzas, George

    2018-06-01

    Managed Aquifer Recharge (MAR) is becoming an attractive water management option, with more than 223 sites operating in European countries. The quality of the produced water, available for drinking or irrigation processes is strongly depended on the aquifer's hydrogeochemical characteristics and on the MAR system design and operation. The objective of this project is the assessment of the operation efficiency of a MAR system in Cyprus. The coupling of alternative methodologies is used such as water quality monitoring, micro-scale sediment sorption experiments, simulation of groundwater flow and phosphate and copper transport in the subsurface using the FEFLOW model and evaluation of the observed change in the chemical composition of water due to mixing using the geochemical model PHREEQC. The above methodology is tested in the Ezousa MAR project in Cyprus, where treated effluent from the Paphos Waste Water Treatment Plant, is recharged into the aquifer through five sets of artificial ponds along the riverbed. Additionally, groundwater is pumped for irrigation purposes from wells located nearby. A slight attenuation of nutrients is observed, whereas copper in groundwater is overcoming the EPA standards. The FEFLOW simulations reveal no effective mixing in some intermediate infiltration ponds, which is validated by the inverse modeling simulation of the PHREEQC model. Based on the results, better control of the infiltration capacity of some of the ponds and increased travel times are some suggestions that could improve the efficiency of the system. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Recharge sources and hydrogeochemical evolution of groundwater in semiarid and karstic environments: A field study in the Granada Basin (Southern Spain)

    International Nuclear Information System (INIS)

    Kohfahl, Claus; Sprenger, Christoph; Herrera, Jose Benavente; Meyer, Hanno; Chacon, Franzisca Fernandez; Pekdeger, Asaf

    2008-01-01

    The objective of this study is to refine the understanding of recharge processes in watersheds representative for karstic semiarid areas by means of stable isotope analysis and hydrogeochemistry. The study focuses on the Granada aquifer system which is located in an intramontane basin bounded by high mountain ranges providing elevation differences of almost 2900 m. These altitude gradients lead to important temperature and precipitation gradients and provide excellent conditions for the application of stable isotopes of water whose composition depends mainly on temperature. Samples of rain, snow, surface water and groundwater were collected at 154 locations for stable isotope studies (δ 18 O, D) and, in the case of ground- and surface waters, also for major and minor ion analysis. Thirty-seven springs were sampled between 2 and 5 times from October 2004 to March 2005 along an altitudinal gradient from 552 masl in the Granada basin to 2156 masl in Sierra Nevada. Nine groundwater samples were taken from the discharge of operating wells in the Granada basin which are all located between 540 and 728 masl. The two main rivers were monitored every 2-3 weeks at three different altitudes. Rainfall being scarce during the sampling period, precipitation could only be sampled during four rainfall events. Calculated recharge altitudes of springs showed that source areas of mainly snowmelt recharge are generally located between 1600 and 2000 masl. The isotope compositions of spring water indicate water sources from the western Mediterranean as well as from the Atlantic without indicating a seasonal trend. The isotope pattern of the Quaternary aquifer reflects the spatial separation of different sources of recharge which occur mainly by bankfiltration of the main rivers. Isotopic signatures in the southeastern part of the aquifer indicate a considerable recharge contribution by subsurface flow discharged from the adjacent carbonate aquifer. No evaporation effects due to

  1. Recharge sources and hydrogeochemical evolution of groundwater in semiarid and karstic environments: A field study in the Granada Basin (Southern Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Kohfahl, Claus [Freie Universitaet Berlin, Institute of Geological Sciences, Malteserstr. 74-100, D-12249 Berlin (Germany)], E-mail: kohfahl@zedat.fu-berlin.de; Sprenger, Christoph [Freie Universitaet Berlin, Institute of Geological Sciences, Malteserstr. 74-100, D-12249 Berlin (Germany); Herrera, Jose Benavente [Instituto del Agua de la Universidad de Granada, Ramon y Cajal, 4, 18071 Granada (Spain); Meyer, Hanno [Isotope Laboratory of the Alfred Wegener Institute for Polar and Marine Research, Research Unit Potsdam, Telegrafenberg A 43, 14473 Potsdam (Germany); Chacon, Franzisca Fernandez [Dpto. Hidrogeologia y Aguas Subterraneas, Instituto Geologico y Minero de Espana, Oficina de Proyectos, Urb. Alcazar del Genil 4, Edificio Zulema bajo, 18006 Granada (Spain); Pekdeger, Asaf [Freie Universitaet Berlin, Institute of Geological Sciences, Malteserstr. 74-100, D-12249 Berlin (Germany)

    2008-04-15

    The objective of this study is to refine the understanding of recharge processes in watersheds representative for karstic semiarid areas by means of stable isotope analysis and hydrogeochemistry. The study focuses on the Granada aquifer system which is located in an intramontane basin bounded by high mountain ranges providing elevation differences of almost 2900 m. These altitude gradients lead to important temperature and precipitation gradients and provide excellent conditions for the application of stable isotopes of water whose composition depends mainly on temperature. Samples of rain, snow, surface water and groundwater were collected at 154 locations for stable isotope studies ({delta}{sup 18}O, D) and, in the case of ground- and surface waters, also for major and minor ion analysis. Thirty-seven springs were sampled between 2 and 5 times from October 2004 to March 2005 along an altitudinal gradient from 552 masl in the Granada basin to 2156 masl in Sierra Nevada. Nine groundwater samples were taken from the discharge of operating wells in the Granada basin which are all located between 540 and 728 masl. The two main rivers were monitored every 2-3 weeks at three different altitudes. Rainfall being scarce during the sampling period, precipitation could only be sampled during four rainfall events. Calculated recharge altitudes of springs showed that source areas of mainly snowmelt recharge are generally located between 1600 and 2000 masl. The isotope compositions of spring water indicate water sources from the western Mediterranean as well as from the Atlantic without indicating a seasonal trend. The isotope pattern of the Quaternary aquifer reflects the spatial separation of different sources of recharge which occur mainly by bankfiltration of the main rivers. Isotopic signatures in the southeastern part of the aquifer indicate a considerable recharge contribution by subsurface flow discharged from the adjacent carbonate aquifer. No evaporation effects due

  2. Isotopic Investigation to Reveal Origin and Recharge of Groundwater in Liwa Area, Western Abu Dhabi, United Arab Emirates (UAE)

    International Nuclear Information System (INIS)

    AlKatheeri, E. S.; Murad, A. A.; Howari, F. M.

    2007-01-01

    Liwa area is located in the Western Region of the Abu Dhabi Emirate in UAE. Environmental isotopes namely 2 H , 1 8O and 3 H were used to study the Quaternary aquifer in the aforementioned area. The analyses indicate that groundwater samples obtained from the study area have significant variation of isotopic content. The range of δ2 H is from -17 to 16.5, while the δ1 8O is ranging from +1.07 to +6.05. This large variation in both oxygen and hydrogen contents may be related to different origin of groundwater. δ2 H - δ1 8O relationship points to potential evaporation of recharged water prior to infiltration as observed from the slope of 4 and y-intercept of about 9. The reported results demonstrate that investigated aquifer is recharged from high elevation source which is Northern Oman Mountains, as seen from the distribution of the samples relative to the LMWL. Groundwater samples have been classified based on their depth to shallow-medium aquifer and deep aquifer. Samples from deeper aquifer have depleted values of isotopes and this indicates that deep groundwater is ancient and originated from rains of different climatic regime.

  3. Determination of timescales of nitrate contamination by groundwater age models in a complex aquifer system

    Science.gov (United States)

    Koh, E. H.; Lee, E.; Kaown, D.; Lee, K. K.; Green, C. T.

    2017-12-01

    Timing and magnitudes of nitrate contamination are determined by various factors like contaminant loading, recharge characteristics and geologic system. Information of an elapsed time since recharged water traveling to a certain outlet location, which is defined as groundwater age, can provide indirect interpretation related to the hydrologic characteristics of the aquifer system. There are three major methods (apparent ages, lumped parameter model, and numerical model) to date groundwater ages, which differently characterize groundwater mixing resulted by various groundwater flow pathways in a heterogeneous aquifer system. Therefore, in this study, we compared the three age models in a complex aquifer system by using observed age tracer data and reconstructed history of nitrate contamination by long-term source loading. The 3H-3He and CFC-12 apparent ages, which did not consider the groundwater mixing, estimated the most delayed response time and a highest period of the nitrate loading had not reached yet. However, the lumped parameter model could generate more recent loading response than the apparent ages and the peak loading period influenced the water quality. The numerical model could delineate various groundwater mixing components and its different impacts on nitrate dynamics in the complex aquifer system. The different age estimation methods lead to variations in the estimated contaminant loading history, in which the discrepancy in the age estimation was dominantly observed in the complex aquifer system.

  4. Golan Heights Groundwater Systems: Separation By REE+Y And Stable Isotopes

    Science.gov (United States)

    Siebert, C.; Geyer, S.; Knoeller, K.; Roediger, T.; Weise, S.; Dulski, P.; Moeller, P.; Guttman, J.

    2008-12-01

    In a semi-arid to arid country like Israel, all freshwater resources are under (over-) utilization. Particularly, the Golan Heights rank as one of the most important extraction areas of groundwater of good quality and quantity. Additionally the mountain range feed to a high degree the most important freshwater reservoir of Israel, the Sea of Galilee. Hence, knowing the sources and characters of the Golan Heights groundwater systems is an instantaneous demand regarding sustainable management and protection. Within the "German-Israeli-Jordanian-Palestinian Joint Research Program for the Sustainable Utilisation of Aquifer Systems", hundreds of water samples were taken from all over the Jordan-Dead Sea rift-system to understand groundwater flow-systems and salinisation. For that purpose, each sample was analysed for major and minor ions, rare earth elements including yttrium (REY) and stable isotopes of water (d18O, d2H). The REY distribution in groundwater is established during infiltration by the first water-rock interaction and consequently reflects the leachable components of sediments and rocks of the recharge area. In well- developed flow-systems, REY are adsorbed onto pore surfaces are in equilibrium with the percolating groundwater, even if the lithology changes (e.g. inter-aquifer flow). Thus, groundwater sampled from wells and springs still show the REY distribution pattern established in the recharge area. Since high temperatures do not occur in Golan Heights, d2H and d18O are less controlled by water-rock interaction than by climatic and geomorphological factors at the time of replenishment. Applying the REY signature as a grouping criterion of groundwaters, d18O vs. d2H plots yield a new dimension in interpreting isotope data. The combined use of hydrochemical and isotopic methods enabled us to contain the areas of replenishment and the flow-paths of all investigated groundwater in the Golan Heights. Despite location, salinity or temperature of spring or

  5. Isotope characteristics of groundwater in Beishan area

    International Nuclear Information System (INIS)

    Guo Yonghai; Liu Shufen; Lu Chuanhe

    2004-01-01

    Using the isotope techniques, the authors studied the origin, evolution and circulation of the groundwater in the potential site of China's high-level waste repository. The results indicate that both deep groundwater and shallow groundwater are mainly recharged by modern and local precipitation, and the deep groundwater in the site area is of meteoric origin. The shallow groundwater is mainly recharged by modern and local precipitation, and the deep groundwater originates from regional precipitation at higher elevation, or might be derived from the precipitation during the geological period of lower temperature. It is also known from the study that the deep underground is a system of very low-permeability where the groundwater flow rates are very low. (author)

  6. Hydrogeologic controls and geochemical indicators of groundwater movement in the Niles Cone and southern East Bay Plain groundwater subbasins, Alameda County, California

    Science.gov (United States)

    Teague, Nicholas F.; Izbicki, John A.; Borchers, Jim; Kulongoski, Justin T.; Jurgens, Bryant C.

    2018-02-01

    Beginning in the 1970s, Alameda County Water District began infiltrating imported water through ponds in repurposed gravel quarries at the Quarry Lakes Regional Park, in the Niles Cone groundwater subbasin, to recharge groundwater and to minimize intrusion of saline, San Francisco Bay water into freshwater aquifers. Hydraulic connection between distinct aquifers underlying Quarry Lakes allows water to recharge the upper aquifer system to depths of 400 feet below land surface, and the Deep aquifer to depths of more than 650 feet. Previous studies of the Niles Cone and southern East Bay Plain groundwater subbasins suggested that these two subbasins may be hydraulically connected. Characterization of storage capacities and hydraulic properties of the complex aquifers and the structural and stratigraphic controls on groundwater movement aids in optimal storage and recovery of recharged water and provides information on the ability of aquifers shared by different water management agencies to fulfill competing storage and extraction demands. The movement of recharge water through the Niles Cone groundwater subbasin from Quarry Lakes and the possible hydraulic connection between the Niles Cone and the southern East Bay Plain groundwater subbasins were investigated using interferometric synthetic aperture radar (InSAR), water-chemistry, and isotopic data, including tritium/helium-3, helium-4, and carbon-14 age-dating techniques.InSAR data collected during refilling of the Quarry Lakes recharge ponds show corresponding ground-surface displacement. Maximum uplift was about 0.8 inches, reasonable for elastic expansion of sedimentary materials experiencing an increase in hydraulic head that resulted from pond refilling. Sodium concentrations increase while calcium and magnesium concentrations in groundwater decrease along groundwater flowpaths from the Niles Cone groundwater subbasin through the Deep aquifer to the northwest toward the southern East Bay Plain groundwater

  7. Documentation of input datasets for the soil-water balance groundwater recharge model of the Upper Colorado River Basin

    Science.gov (United States)

    Tillman, Fred D.

    2015-01-01

    The Colorado River and its tributaries supply water to more than 35 million people in the United States and 3 million people in Mexico, irrigating more than 4.5 million acres of farmland, and generating about 12 billion kilowatt hours of hydroelectric power annually. The Upper Colorado River Basin, encompassing more than 110,000 square miles (mi2), contains the headwaters of the Colorado River (also known as the River) and is an important source of snowmelt runoff to the River. Groundwater discharge also is an important source of water in the River and its tributaries, with estimates ranging from 21 to 58 percent of streamflow in the upper basin. Planning for the sustainable management of the Colorado River in future climates requires an understanding of the Upper Colorado River Basin groundwater system. This report documents input datasets for a Soil-Water Balance groundwater recharge model that was developed for the Upper Colorado River Basin.

  8. Spatial and temporal variability of groundwater recharge in Geba basin, Northern Ethiopia

    Science.gov (United States)

    Yenehun, Alemu; Walraevens, Kristine; Batelaan, Okke

    2017-10-01

    WetSpa, a physically based, spatially distributed watershed model, has been used to study the spatial and temporal variation of recharge in the Geba basin, Northern Ethiopia. The model covers an area of about 4, 249 km2 and integrates elevation, soil and land-use data, hydrometeorological and river discharge data. The Geba basin has a highly variable topography ranging from 1000 to 3280 m with an average slope of 12.9%. The area is characterized by a distinct wet and long dry season with a mean annual precipitation of 681 mm and temperatures ranging between 6.5 °C and 32 °C. The model was simulated on daily basis for nearly four years (January 1, 2000 to December 18, 2003). It resulted in a good agreement between measured and simulated streamflow hydrographs with Nash-Sutcliffe efficiency of almost 70% and 85% for, respectively, the calibration and validation. The water balance terms show very strong spatial and temporal variability, about 3.8% of the total precipitation is intercepted by the plant canopy; 87.5% infiltrates into the soil (of which 13% percolates, 2.7% flows laterally off and 84.2% evapotranspired from the root zone), and 7.2% is surface runoff. The mean annual recharge varies from about 45 mm (2003) to 208 mm (2001), with average of 98.6 mm/yr. On monthly basis, August has the maximum (73 mm) and December the lowest (0.1 mm) recharge. The mean annual groundwater recharge spatially varies from 0 to 371 mm; mainly controlled by the distribution of rainfall amount, followed by soil and land-use, and to a certain extent, slope. About 21% of Geba has a recharge larger than 120 mm and 1% less than 5 mm.

  9. Recharge mechanism in karstic systems investigation through the correlation of chemical and isotopic composition of rain and spring-water (case study: Figeh and Barada springs)

    International Nuclear Information System (INIS)

    Al-Charideh, A.

    2012-03-01

    Karst aquifers represents an important groundwater resources not only in Syria, but in the world-wide. The hydrological approaches for studying the karst system were developed in the last tow decade. One of the main approaches is the use of natural isotopes and hydrochemical traces for description the recharge and discharge and estimate the recharge rate of karst aquifer system. The main filed site tests are the Figeh and Barada karst aquifer, located in the carbonate rocks of the Anti-Lebanon Mountains. Environmental isotopes and chemical major ions (δ 18 Ο, δ 2 H and 3 H), in precipitation and groundwater were integrated for studying the isotope and hydrochemical characterization and the description of temporal variations of groundwater discharge from the karst springs of Figeh and Barada which are considered as the main large springs due to there huge discharge in the Anti-Lebanon Mountains. The δ 18 O values are -8.9 and -7.7. for Figeh and Barada respectively. The regression line for both precipitation and groundwater discharge from Figeh and Barada is described by the equation: δD = 7.9δ 18 O + 19.7 wish shows no evaporation during precipitation and suggest that the groundwater are mainly from direct infiltration of precipitation. The altitude gradients in the precipitation were estimated to be -0.23./100 m for δ 18 O. The main recharge areas were estimated to be 2000±50 and 1350±50 m.a.s.l for Figeh and Barada springs.The chloride mass balance (CMB) method was used to quantify recharge rates of groundwater in the Mountain karst aquifer of Figeh spring. The recharge rate varies from 192 to 825 mm year-1, which corresponds to 43 and 67% of the total annual rainfall. Recharge rates estimated by CMB were compared with values obtained from other methods and were found to be in good agreement. The tritium concentrations in groundwater are low and very close to the rainfall value 4.5 Tu for meteoric stations. Adopting a model with exponential time

  10. Simulation of ground-water flow and land subsidence in the Antelope Valley ground-water basin, California

    Science.gov (United States)

    Leighton, David A.; Phillips, Steven P.

    2003-01-01

    Antelope Valley, California, is a topographically closed basin in the western part of the Mojave Desert, about 50 miles northeast of Los Angeles. The Antelope Valley ground-water basin is about 940 square miles and is separated from the northern part of Antelope Valley by faults and low-lying hills. Prior to 1972, ground water provided more than 90 percent of the total water supply in the valley; since 1972, it has provided between 50 and 90 percent. Most ground-water pumping in the valley occurs in the Antelope Valley ground-water basin, which includes the rapidly growing cities of Lancaster and Palmdale. Ground-water-level declines of more than 200 feet in some parts of the ground-water basin have resulted in an increase in pumping lifts, reduced well efficiency, and land subsidence of more than 6 feet in some areas. Future urban growth and limits on the supply of imported water may continue to increase reliance on ground water. To better understand the ground-water flow system and to develop a tool to aid in effectively managing the water resources, a numerical model of ground-water flow and land subsidence in the Antelope Valley ground-water basin was developed using old and new geohydrologic information. The ground-water flow system consists of three aquifers: the upper, middle, and lower aquifers. The aquifers, which were identified on the basis of the hydrologic properties, age, and depth of the unconsolidated deposits, consist of gravel, sand, silt, and clay alluvial deposits and clay and silty clay lacustrine deposits. Prior to ground-water development in the valley, recharge was primarily the infiltration of runoff from the surrounding mountains. Ground water flowed from the recharge areas to discharge areas around the playas where it discharged either from the aquifer system as evapotranspiration or from springs. Partial barriers to horizontal ground-water flow, such as faults, have been identified in the ground-water basin. Water-level declines owing to

  11. Stable isotopes (2H, 18O and 13C) in groundwaters from the northwestern portion of the Guarani Aquifer System (Brazil)

    Science.gov (United States)

    Gastmans, Didier; Chang, Hung Kiang; Hutcheon, Ian

    2010-09-01

    The groundwater flow pattern of the western part of the Guarani Aquifer System (GAS), Brazil, is characterized by three regional recharge areas in the north, and a potentiometric divide in the south, which trends north-south approximately. Groundwater flow is radial from these regional recharge areas toward the center of Paraná Sedimentary Basin and toward the western outcrop areas at the border of the Pantanal Matogrossense, because of the potentiometric divide. The isotopic composition of GAS groundwater leads to understanding the paleoclimatic conditions in the regional recharge areas. The δ18O and δ2H isotopic ratios of GAS groundwaters vary, respectively, from -9.1 to -4.8‰ V-SMOW and -58.4 to -21.7‰ V-SMOW. In the recharge zones, enriched δ18O values are observed, while in the confined zone lighter δ18O values are observed. These suggest that climatic conditions were 10°C cooler than the present during the recharge of these waters. The δ13C ratios in groundwater of GAS, in the study area, vary from -19.5 to -6.5‰ VPDB, increasing along the regional flow lines toward the confined zone. This variation is related to dissolution of carbonate cement in the sandstones.

  12. Groundwater movement, recharge, and perchlorate occurrence in a faulted alluvial aquifer in California (USA)

    Science.gov (United States)

    Izbicki, John A.; Teague, Nicholas F.; Hatzinger, Paul B.; Böhlke, John Karl; Sturchio, Neil C.

    2015-01-01

    Perchlorate from military, industrial, and legacy agricultural sources is present within an alluvial aquifer in the Rialto-Colton groundwater subbasin, 80 km east of Los Angeles, California (USA). The area is extensively faulted, with water-level differences exceeding 60 m across parts of the Rialto-Colton Fault separating the Rialto-Colton and Chino groundwater subbasins. Coupled well-bore flow and depth-dependent water-quality data show decreases in well yield and changes in water chemistry and isotopic composition, reflecting changing aquifer properties and groundwater recharge sources with depth. Perchlorate movement through some wells under unpumped conditions from shallower to deeper layers underlying mapped plumes was as high as 13 kg/year. Water-level maps suggest potential groundwater movement across the Rialto-Colton Fault through an overlying perched aquifer. Upward flow through a well in the Chino subbasin near the Rialto-Colton Fault suggests potential groundwater movement across the fault through permeable layers within partly consolidated deposits at depth. Although potentially important locally, movement of groundwater from the Rialto-Colton subbasin has not resulted in widespread occurrence of perchlorate within the Chino subbasin. Nitrate and perchlorate concentrations at the water table, associated with legacy agricultural fertilizer use, may be underestimated by data from long-screened wells that mix water from different depths within the aquifer.

  13. Impacts of changes in groundwater recharge on the isotopic composition and geochemistry of seasonally ice-covered lakes: insights for sustainable management

    Directory of Open Access Journals (Sweden)

    M. Arnoux

    2017-11-01

    Full Text Available Lakes are under increasing pressure due to widespread anthropogenic impacts related to rapid development and population growth. Accordingly, many lakes are currently undergoing a systematic decline in water quality. Recent studies have highlighted that global warming and the subsequent changes in water use may further exacerbate eutrophication in lakes. Lake evolution depends strongly on hydrologic balance, and therefore on groundwater connectivity. Groundwater also influences the sensitivity of lacustrine ecosystems to climate and environmental changes, and governs their resilience. Improved characterization of groundwater exchange with lakes is needed today for lake preservation, lake restoration, and sustainable management of lake water quality into the future. In this context, the aim of the present paper is to determine if the future evolution of the climate, the population, and the recharge could modify the geochemistry of lakes (mainly isotopic signature and quality via phosphorous load and if the isotopic monitoring of lakes could be an efficient tool to highlight the variability of the water budget and quality. Small groundwater-connected lakes were chosen to simulate changes in water balance and water quality expected under future climate change scenarios, namely representative concentration pathways (RCPs 4.5 and 8.5. Contemporary baseline conditions, including isotope mass balance and geochemical characteristics, were determined through an intensive field-based research program prior to the simulations. Results highlight that future lake geochemistry and isotopic composition trends will depend on four main parameters: location (and therefore climate conditions, lake catchment size (which impacts the intensity of the flux change, lake volume (which impacts the range of variation, and lake G index (i.e., the percentage of groundwater that makes up total lake inflows, the latter being the dominant control on water balance conditions, as

  14. Impacts of changes in groundwater recharge on the isotopic composition and geochemistry of seasonally ice-covered lakes: insights for sustainable management

    Science.gov (United States)

    Arnoux, Marie; Barbecot, Florent; Gibert-Brunet, Elisabeth; Gibson, John; Noret, Aurélie

    2017-11-01

    Lakes are under increasing pressure due to widespread anthropogenic impacts related to rapid development and population growth. Accordingly, many lakes are currently undergoing a systematic decline in water quality. Recent studies have highlighted that global warming and the subsequent changes in water use may further exacerbate eutrophication in lakes. Lake evolution depends strongly on hydrologic balance, and therefore on groundwater connectivity. Groundwater also influences the sensitivity of lacustrine ecosystems to climate and environmental changes, and governs their resilience. Improved characterization of groundwater exchange with lakes is needed today for lake preservation, lake restoration, and sustainable management of lake water quality into the future. In this context, the aim of the present paper is to determine if the future evolution of the climate, the population, and the recharge could modify the geochemistry of lakes (mainly isotopic signature and quality via phosphorous load) and if the isotopic monitoring of lakes could be an efficient tool to highlight the variability of the water budget and quality. Small groundwater-connected lakes were chosen to simulate changes in water balance and water quality expected under future climate change scenarios, namely representative concentration pathways (RCPs) 4.5 and 8.5. Contemporary baseline conditions, including isotope mass balance and geochemical characteristics, were determined through an intensive field-based research program prior to the simulations. Results highlight that future lake geochemistry and isotopic composition trends will depend on four main parameters: location (and therefore climate conditions), lake catchment size (which impacts the intensity of the flux change), lake volume (which impacts the range of variation), and lake G index (i.e., the percentage of groundwater that makes up total lake inflows), the latter being the dominant control on water balance conditions, as revealed by

  15. Dynamics of dissolved organic carbon (DOC) through stormwater basins designed for groundwater recharge in urban area: Assessment of retention efficiency.

    Science.gov (United States)

    Mermillod-Blondin, Florian; Simon, Laurent; Maazouzi, Chafik; Foulquier, Arnaud; Delolme, Cécile; Marmonier, Pierre

    2015-09-15

    Managed aquifer recharge (MAR) has been developed in many countries to limit the risk of urban flooding and compensate for reduced groundwater recharge in urban areas. The environmental performances of MAR systems like infiltration basins depend on the efficiency of soil and vadose zone to retain stormwater-derived contaminants. However, these performances need to be finely evaluated for stormwater-derived dissolved organic matter (DOM) that can affect groundwater quality. Therefore, this study examined the performance of MAR systems to process DOM during its transfer from infiltration basins to an urban aquifer. DOM characteristics (fluorescent spectroscopic properties, biodegradable and refractory fractions of dissolved organic carbon -DOC-, consumption by micro-organisms during incubation in slow filtration sediment columns) were measured in stormwater during its transfer through three infiltration basins during a stormwater event. DOC concentrations sharply decreased from surface to the aquifer for the three MAR sites. This pattern was largely due to the retention of biodegradable DOC which was more than 75% for the three MAR sites, whereas the retention of refractory DOC was more variable and globally less important (from 18% to 61% depending on MAR site). Slow filtration column experiments also showed that DOC retention during stormwater infiltration through soil and vadose zone was mainly due to aerobic microbial consumption of the biodegradable fraction of DOC. In parallel, measurements of DOM characteristics from groundwaters influenced or not by MAR demonstrated that stormwater infiltration increased DOC quantity without affecting its quality (% of biodegradable DOC and relative aromatic carbon content -estimated by SUVA254-). The present study demonstrated that processes occurring in soil and vadose zone of MAR sites were enough efficient to limit DOC fluxes to the aquifer. Nevertheless, the enrichments of DOC concentrations measured in groundwater below

  16. Implications of deep drainage through saline clay for groundwater recharge and sustainable cropping in a semi-arid catchment, Australia

    Directory of Open Access Journals (Sweden)

    W. A. Timms

    2012-04-01

    Full Text Available The magnitude and timing of deep drainage and salt leaching through clay soils is a critical issue for dryland agriculture in semi-arid regions (<500 mm yr−1 rainfall, potential evapotranspiration >2000 mm yr−1 such as parts of Australia's Murray-Darling Basin (MDB. In this rare study, hydrogeological measurements and estimations of the historic water balance of crops grown on overlying Grey Vertosols were combined to estimate the contribution of deep drainage below crop roots to recharge and salinization of shallow groundwater. Soil sampling at two sites on the alluvial flood plain of the Lower Namoi catchment revealed significant peaks in chloride concentrations at 0.8–1.2 m depth under perennial vegetation and at 2.0–2.5 m depth under continuous cropping indicating deep drainage and salt leaching since conversion to cropping. Total salt loads of 91–229 t ha−1 NaCl equivalent were measured for perennial vegetation and cropping, with salinity to ≥ 10 m depth that was not detected by shallow soil surveys. Groundwater salinity varied spatially from 910 to 2430 mS m−1 at 21 to 37 m depth (N = 5, whereas deeper groundwater was less saline (290 mS m−1 with use restricted to livestock and rural domestic supplies in this area. The Agricultural Production Systems Simulator (APSIM software package predicted deep drainage of 3.3–9.5 mm yr−1 (0.7–2.1% rainfall based on site records of grain yields, rainfall, salt leaching and soil properties. Predicted deep drainage was highly episodic, dependent on rainfall and antecedent soil water content, and over a 39 yr period was restricted mainly to the record wet winter of 1998. During the study period, groundwater levels were unresponsive to major rainfall events (70 and 190 mm total, and most piezometers at about 18 m depth remained dry. In this area, at this time, recharge appears to be negligible due to low

  17. H-O isotopic and chemical characteristics of a precipitation-lake water-groundwater system in a desert area

    Science.gov (United States)

    Jin, Ke; Rao, Wenbo; Tan, Hongbing; Song, Yinxian; Yong, Bin; Zheng, Fangwen; Chen, Tangqing; Han, Liangfeng

    2018-04-01

    The recharge mechanism of groundwater in the Badain Jaran Desert, North China has been a focus of research and still disputable in the past two decades. In this study, the chemical and hydrogen (H) and oxygen (O) isotopic characteristics of shallow groundwater, lake water and local precipitation in the Badain Jaran Desert and neighboring areas were investigated to reveal the relationships between various water bodies and the recharge source of shallow groundwater. Isotopic and hydrogeochemical results show that (1) shallow groundwater was associated with local precipitation in the Ayouqi and Yabulai regions, (2) lake water was mainly recharged by groundwater in the desert hinterland, (3) shallow groundwater of the desert hinterland, Yabulai Mountain and Gurinai Grassland had a common recharge source. Shallow groundwater of the desert hinterland had a mean recharge elevation of 1869 m a.s.l. on the basis of the isotope-altitude relationship and thus originated chiefly from lateral infiltration of precipitation in the Yabulai Mountain. It is further concluded that shallow groundwater flowed towards the Gurinai Grassland according to the groundwater table contour map. Along the flow pathway, the H-O isotopic variations were primarily caused by the evaporation effect but chemical variations of shallow groundwater were affected by multiple factors, e.g., evaporation effect, dilution effect of occasional heavy-precipitation and dissolution of aquifer evaporites. Our findings provide new insight into the groundwater cycle and benefit the management of the limited water resources in the arid desert area.

  18. Ground-Water Budgets for the Wood River Valley Aquifer System, South-Central Idaho, 1995-2004

    Science.gov (United States)

    Bartolino, James R.

    2009-01-01

    The Wood River Valley contains most of the population of Blaine County and the cities of Sun Valley, Ketchum, Haley, and Bellevue. This mountain valley is underlain by the alluvial Wood River Valley aquifer system which consists of a single unconfined aquifer that underlies the entire valley, an underlying confined aquifer that is present only in the southernmost valley, and the confining unit that separates them. The entire population of the area depends on ground water for domestic supply, either from domestic or municipal-supply wells, and rapid population growth since the 1970s has caused concern about the long-term sustainability of the ground-water resource. To help address these concerns this report describes a ground-water budget developed for the Wood River Valley aquifer system for three selected time periods: average conditions for the 10-year period 1995-2004, and the single years of 1995 and 2001. The 10-year period 1995-2004 represents a range of conditions in the recent past for which measured data exist. Water years 1995 and 2001 represent the wettest and driest years, respectively, within the 10-year period based on precipitation at the Ketchum Ranger Station. Recharge or inflow to the Wood River Valley aquifer system occurs through seven main sources (from largest to smallest): infiltration from tributary canyons, streamflow loss from the Big Wood River, areal recharge from precipitation and applied irrigation water, seepage from canals and recharge pits, leakage from municipal pipes, percolation from septic systems, and subsurface inflow beneath the Big Wood River in the northern end of the valley. Total estimated mean annual inflow or recharge to the aquifer system for 1995-2004 is 270,000 acre-ft/yr (370 ft3/s). Total recharge for the wet year 1995 and the dry year 2001 is estimated to be 270,000 acre-ft/yr (370 ft3/s) and 220,000 acre-ft/yr (300 ft3/s), respectively. Discharge or outflow from the Wood River Valley aquifer system occurs through

  19. Hydrochemistry of the Mahomet Bedrock Valley Aquifer, East-Central Illinois: indicators of recharge and ground-water flow

    Science.gov (United States)

    Panno, S.V.; Hackley, Keith C.; Cartwright, K.; Liu, Chao-Li

    1994-01-01

    A conceptual model of the ground-water flow and recharge to the Mahomet Bedrock Valley Aquifer (MVA), east-central Illinois, was developed using major ion chemistry and isotope geochemistry. The MVA is a 'basal' fill in the east-west trending buried bedrock valley composed of clean, permeable sand and gravel to thicknesses of up to 61 m. It is covered by a thick sequence of glacial till containing thinner bodies of interbedded sand and gravel. Ground water from the MVA was found to be characterized by clearly defined geochemical regions with three distinct ground-water types. A fourth ground-water type was found at the confluence of the MVA and the Mackinaw Bedrock Valley Aquifer (MAK) to the west. Ground water in the Onarga Valley, a northeastern tributary of the MVA, is of two types, a mixed cation-SO42- type and a mixed cation-HCO3- type. The ground water is enriched in Na+, Ca2+, Mg2+, and SO42- which appears to be the result of an upward hydraulic gradient and interaction of deeper ground water with oxidized pyritic coals and shale. We suggest that recharge to the Onarga Valley and overlying aquifers is 100% from bedrock (leakage) and lateral flow from the MVA to the south. The central MVA (south of the Onarga Valley) is composed of relatively dilute ground water of a mixed cation-HCO3- type, with low total dissolved solids, and very low concentrations of Cl- and SO42-. Stratigraphic relationships of overlying aquifers and ground-water chemistry of these and the MVA suggest recharge to this region of the MVA (predominantly in Champaign County) is relatively rapid and primarily from the surface. Midway along the westerly flow path of the MVA (western MVA), ground water is a mixed cation-HCO3- type with relatively high Cl-, where Cl- increases abruptly by one to ??? two orders of magnitude. Data suggest that the increase in Cl- is the result of leakage of saline ground water from bedrock into the MVA. Mass-balance calculations indicate that approximately 9.5% of

  20. Using GRACE Amplitude Data in Conjunction with the Spatial Distribution of Groundwater Recharge to Estimate the Components of the Terrestrial Water Storage Anomaly across the Contiguous United States

    Science.gov (United States)

    Sanford, W. E.; Reitz, M.; Zell, W.

    2017-12-01

    The GRACE satellite project by NASA has been mapping the terrestrial water storage anomaly (TWSA) across the globe since 2002. To date most of the studies using this data have focused on estimating long-term storage declines in groundwater aquifers or the cryosphere. In this study we are focusing on using the amplitude of the seasonal storage signal to estimate the sources and values of the different water components that are contributing to the TWSA signal across the contiguous United States (CONUS). Across the CONUS the TWSA seasonal amplitude observed by GRACE varies by a factor of ten or more (from 1 to 10+ cm of liquid water equivalent). For a seasonal sinusoidal recharge rate, the change in storage in either the soil (unsaturated zone beneath the root zone) or groundwater (by water-table fluctuation) is limited to the amplitude of the recharge rate divided by π or 2π, respectively. We compiled the GRACE signal for the 18 major HUC watersheds across the CONUS and compared them to estimates of seasonal recharge-rate amplitudes based on a recent map of recharge rates generated by the USGS. The ratios of the recharge to GRACE amplitudes suggest that all but two of the HUCs must have other substantial sources of storage change in addition to soil or groundwater. The most likely additional sources are (1) winter snowpack, (2) seasonal irrigation withdrawals, and/or (3) surface water (rivers or reservoirs). Estimates of the seasonal amplitudes of these three signals across the CONUS suggest they can explain the remaining GRACE seasonal signal that cannot be explained by soil or groundwater fluctuations. Each of these signals has its own unique spatial distribution, with snowpack limited to the northern states, surface water limited to large rivers or reservoirs, and irrigation as a dominant signal limited to arid to semi-arid agricultural regions. Use of the GRACE seasonal signal shows promise in constraining the hydraulic diffusivities of surficial aquifer

  1. Investigation of Groundwater Flow Variations near a Recharge Pond with Repeat Deliberate Tracer Experiments

    Directory of Open Access Journals (Sweden)

    Jordan F Clark

    2014-06-01

    Full Text Available Determining hydraulic connections and travel times between recharge facilities and production wells has become increasingly important for permitting and operating managed aquifer recharge (MAR sites, a water supply strategy that transfers surface water into aquifers for storage and later extraction. This knowledge is critical for examining water quality changes and assessing the potential for future contamination. Deliberate tracer experiments are the best method for determining travel times and identifying preferential flow paths between recharge sites over the time scales of weeks to a few years. This paper compares the results of two deliberate tracer experiments at Kraemer Basin, Orange County, CA, USA. Results from the first experiment, which was conducted in October 1998, showed that a region of highly transmissive sedimentary material extends down gradient from the basin for more than 3 km [1]. Mean groundwater velocities were determined to be approximately 2 km/year in this region based on the arrival time of the tracer center of mass. A second experiment was initiated in January 2008 to determine if travel times from this basin to monitoring and production wells changed during the past decade in response to new recharge conditions. Results indicate that flow near Kraemer Basin was stable, and travel times to most wells determined during both experiments agree within the experimental uncertainty.

  2. The effects of artificial recharge on groundwater levels and water quality in the west hydrogeologic unit of the Warren subbasin, San Bernardino County, California

    Science.gov (United States)

    Stamos, Christina L.; Martin, Peter; Everett, Rhett; Izbicki, John A.

    2013-01-01

    Between the late 1940s and 1994, groundwater levels in the Warren subbasin, California, declined by as much as 300 feet because pumping exceeded sparse natural recharge. In response, the local water district, Hi-Desert Water District, implemented an artificial-recharge program in early 1995 using imported water from the California State Water Project. Subsequently, the water table rose by as much as 250 feet; however, a study done by the U.S. Geological Survey found that the rising water table entrained high-nitrate septic effluent, which caused nitrate (as nitrogen) concentrations in some wells to increase to more than the U.S. Environmental Protection Agency maximum contaminant level of 10 milligrams per liter.. A new artificial-recharge site (site 3) was constructed in 2006 and this study, which started in 2004, was done to address concerns about the possible migration of nitrates in the unsaturated zone. The objectives of this study were to: (1) characterize the hydraulic, chemical, and microbiological properties of the unsaturated zone; (2) monitor changes in water levels and water quality in response to the artificial-recharge program at site 3; (3) determine if nitrates from septic effluent infiltrated through the unsaturated zone to the water table; (4) determine the potential for nitrates within the unsaturated zone to mobilize and contaminate the groundwater as the water table rises in response to artificial recharge; and (5) determine the presence and amount of dissolved organic carbon because of its potential to react with disinfection byproducts during the treatment of water for public use. Two monitoring sites were installed and instrumented with heat-dissipation probes, advanced tensiometers, suction-cup lysimeters, and wells so that the arrival and effects of recharging water from the State Water Project through the 250 to 425 foot-thick unsaturated zone and groundwater system could be closely observed. Monitoring site YVUZ-1 was located between two

  3. Contribution to the study of the recharge of Morondava hydrogeological basin

    International Nuclear Information System (INIS)

    RAHOBISOA, J.J.

    2006-01-01

    Stables isotopes and radioisotopes, combinated with hydrogeological data and hydrochemical data have been applied in the investigation of the groundwater recharge of the Morondava plain. This area is located in the south western of Madagascar, in the catchment of Morondava river. The dominant hydrochemical type of the groundwaters in the study area is of calcium-bicarbonate, with sodium chloride type in the coastal and central areas. They may originate from dissolution of limestone; or from hydrolysis of Anorthite; or from sea sprays. The phreatic aquifer receives both direct and lateral recharge by rainfall. The average recharge rate is estimated to 165,7 to 182,7 mm/a corresponding to a recharge of 250 614.10 3 to 276 318.10 3 m 3 /a. As for the deeper aquifer, the groundwater recharge area is mainly located in Tsiandava plateau according to the isotopic recharge altitude calculations. As for the phreatic aquifer, tritium values have provided a mean residence time of 56 years. As for the deeper aquifers, the 14 C groundwater age ranges between 1400 and 1985 years [fr

  4. Isotope studies on mechanisms of groundwater recharge to an alluvial aquifer in Gatton, Queensland, Australia

    International Nuclear Information System (INIS)

    Dharmasiri, J.K.; Morawska, L.

    1997-01-01

    Gatton is an important agricultural area for Queensland where about 40% of its vegetables needs are produced using groundwater as the main source. An alluvial Aquifer is located about 30m beneath the layers of alluvial sediments ranging from black soils of volcanic origin on top, layers of alluvial sands, clays and beds of sand and gravel. The leakage of creek flows has been considered to be the main source of recharge to this aquifer. A number of weirs have been built across the Lockyer and Laidley creeks to allow surface water to infiltrate through the beds when the creeks flow. Water levels in bores in a section located in the middle of the alluvial plain (Crowley Vale) have been declining for the last 20 years with little or no success in recharging from the creeks. Acute water shortages have been experienced in the Gatton area during the droughts of 1980-81, 1986-87 and 1994-97. Naturally occurring stable isotopes, 2 H, 18 0 and 13 C as well as radioisotopes 3 H and 14 C have been used to delineate sources of recharge and active recharge areas. Tritium tracing of soil moisture in the unsaturated soil was also used to determine direct infiltration rates

  5. Groundwater recharge and discharge scenarios for a nuclear waste repository in bedded salt

    International Nuclear Information System (INIS)

    Carpenter, D.W.; Steinborn, T.L.; Thorson, L.D.

    1979-01-01

    Twelve potential scenarios have been identified whereby groundwater may enter or exit a nuclear waste repository in bedded salt. The 12 scenarios may be grouped into 4 categories or failure modes: dissolution, fracturing, voids, and penetration. Dissolution modes include breccia pipe and breccia blanket formation, and dissolution around boreholes. Fracture modes include flow through preexisting or new fractures and the effects of facies changes. Voids include interstitial voids (pores) and fluid inclusions. Penetration modes include shaft and borehole sealing failures, undetected boreholes, and new mines or wells constructed after repository decommissioning. The potential importance of thermal effects on groundwater flow patterns and on the recharge-discharge process is discussed. The appropriate levels of modeling effort, and the interaction between the adequacy of the geohydrologic data base and the warranted degree of model complexity are also discussed

  6. The recharge area concept: A strategy for siting nuclear waste repositories

    International Nuclear Information System (INIS)

    Sheng, G.; Toth, J.

    2000-01-01

    The Recharge Area Concept is the proposition that in Canadian-Shield type natural environments recharge areas of regional groundwater flow systems are superior for high-level nuclear waste repositories to other types of groundwater flow regimes, especially to areas of groundwater discharge. This conclusion is reached from an analysis of basinal groundwater flow models. The calculations were made for a two-dimensional flank of a fully saturated topographic basin, 20 km long and 4 km deep, in which groundwater is driven by gravity. Variants of hydraulic-conductivity distributions were considered: 1) homogeneous; 2) stratified; and 3) stratified-faulted. The faults attitudes were changed by steps from vertical to horizontal for different variants. The model is assumed conceptually to represent the crystalline-rock environment of the Canadian Shield. The hydrogeologic performances of hypothetical repositories placed 500 m deep in the recharge and discharge areas were characterized by thirteen parameters. The principal advantages of recharge- over discharge-area locations are: 1) longer travel paths and return-flow times from repository to surface; 2) robustness of predicted values of performance parameters; 3) field-verifiability of favourable hydrogeologic conditions (amounting to an implicit validation of the calculated minimum values of return-flow times); 4) site acceptance based on quantifiable and observable flow-controlling parameters; and 5) simple logistics and favourable economics of site selection and screening. As a by-product of modeling, it is demonstrated that the presence of old water is not an indication of stagnancy. (author)

  7. A Regional Groundwater Observatory to Enhance Analysis and Management of Water Resources

    Science.gov (United States)

    Yoder, A. M.; Maples, S.; Hatch, N. R.; Fogg, G. E.

    2017-12-01

    Timely, effective management of groundwater often does not happen because timely information on the state of the groundwater system is seldom available. A groundwater observatory for monitoring real-time groundwater level fluctuations is being developed in the American-Cosumnes groundwater system of Sacramento County, California. The observatory records the consequences of complex interplay between pumpage, recharge, drought, and floods in the context of a heterogeneous stratigraphic framework that has been extensively characterized with more than 1,100 well logs. Preliminary results show increases in recharge caused by removal of flood control levees to allow more frequent floodplain inundation as well as consequences of the 2012-16 drought followed by the wet winter of 2016-17. Comparison of recharge rates pre- and post-levee breach restoration show significant increases in recharge, despite the presence of fine-grained floodplain soils. Estimated total recharge corresponded closely with the frequency and magnitude of flood events in any given water year. The lowest value calculated for estimated recharge was from 2012-2013, 490 +/- 220 ac-ft (0.65 +/- 0.29 ac-ft per acre). The highest estimated recharge value calculated was for the 2015-2016 water year and was 3180 +/- 1430 ac-ft (2.83 +/- 1.27 ac-ft per acre). These preliminary numbers will be updated with more comprehensive estimates based on a full analysis of the 2016-17 data. The increase in data transfer efficiency afforded by the observatory can be widely used by the many parties reliant on Central Valley groundwater and can serve as a model for real-time data collection in support of California's Sustainable Groundwater Management Act, passed in 2014.

  8. Ecohydrologic process modeling of mountain block groundwater recharge.

    Science.gov (United States)

    Magruder, Ian A; Woessner, William W; Running, Steve W

    2009-01-01

    Regional mountain block recharge (MBR) is a key component of alluvial basin aquifer systems typical of the western United States. Yet neither water scientists nor resource managers have a commonly available and reasonably invoked quantitative method to constrain MBR rates. Recent advances in landscape-scale ecohydrologic process modeling offer the possibility that meteorological data and land surface physical and vegetative conditions can be used to generate estimates of MBR. A water balance was generated for a temperate 24,600-ha mountain watershed, elevation 1565 to 3207 m, using the ecosystem process model Biome-BGC (BioGeochemical Cycles) (Running and Hunt 1993). Input data included remotely sensed landscape information and climate data generated with the Mountain Climate Simulator (MT-CLIM) (Running et al. 1987). Estimated mean annual MBR flux into the crystalline bedrock terrain is 99,000 m(3) /d, or approximately 19% of annual precipitation for the 2003 water year. Controls on MBR predictions include evapotranspiration (radiation limited in wet years and moisture limited in dry years), soil properties, vegetative ecotones (significant at lower elevations), and snowmelt (dominant recharge process). The ecohydrologic model is also used to investigate how climatic and vegetative controls influence recharge dynamics within three elevation zones. The ecohydrologic model proves useful for investigating controls on recharge to mountain blocks as a function of climate and vegetation. Future efforts will need to investigate the uncertainty in the modeled water balance by incorporating an advanced understanding of mountain recharge processes, an ability to simulate those processes at varying scales, and independent approaches to calibrating MBR estimates. Copyright © 2009 The Author(s). Journal compilation © 2009 National Ground Water Association.

  9. Combining hydrologic and groundwater modelling to characterize a regional aquifer system within a rift setting (Gidabo River Basin, Main Ethiopian Rift)

    Science.gov (United States)

    Birk, Steffen; Mechal, Abraham; Wagner, Thomas; Dietzel, Martin; Leis, Albrecht; Winkler, Gerfried; Mogessie, Aberra

    2016-04-01

    The development of groundwater resources within the Ethiopian Rift is complicated by the strong physiographic contrasts between the rift floor and the highland and by the manifold hydrogeological setting composed of volcanic rocks of different type and age that are intersected by numerous faults. Hydrogeochemical and isotope data from various regions within the Ethiopian Rift suggest that the aquifers within the semi-arid rift floor receive a significant contribution of groundwater flow from the humid highland. For example, the major ion composition of groundwater samples from Gidabo River Basin (3302 km²) in the southern part of the Main Ethiopian Rift reveals a mixing trend from the highland toward the rift floor; moreover, the stable isotopes of water, deuterium and O-18, of the rift-floor samples indicate a component recharged in the highland. This work aims to assess if the hydrological and hydrogeological data available for Gidabo River Basin is consistent with these findings and to characterize the regional aquifer system within the rift setting. For this purpose, a two-step approach is employed: First, the semi-distributed hydrological model SWAT is used to obtain an estimate of the spatial and temporal distribution of groundwater recharge within the watershed; second, the numerical groundwater flow model MODFLOW is employed to infer aquifer properties and groundwater flow components. The hydrological model was calibrated and validated using discharge data from three stream gauging stations within the watershed (Mechal et al., Journal of Hydrology: Regional Studies, 2015, doi:10.1016/j.ejrh.2015.09.001). The resulting recharge distribution exhibits a strong decrease from the highland, where the mean annual recharge amounts to several hundred millimetres, to the rift floor, where annual recharge largely is around 100 mm and below. Using this recharge distribution as input, a two-dimensional steady-state groundwater flow model was calibrated to hydraulic

  10. Recharge and Groundwater Flow Within an Intracratonic Basin, Midwestern United States.

    Science.gov (United States)

    Panno, Samuel V; Askari, Zohreh; Kelly, Walton R; Parris, Thomas M; Hackley, Keith C

    2018-01-01

    The conservative nature of chloride (Cl - ) in groundwater and the abundance of geochemical data from various sources (both published and unpublished) provided a means of developing, for the first time, a representation of the hydrogeology of the Illinois Basin on a basin-wide scale. The creation of Cl - isocons superimposed on plan view maps of selected formations and on cross sections across the Illinois Basin yielded a conceptual model on a basin-wide scale of recharge into, groundwater flow within and through the Illinois Basin. The maps and cross sections reveal the infiltration and movement of freshwater into the basin and dilution of brines within various geologic strata occurring at basin margins and along geologic structures. Cross-formational movement of brines is also seen in the northern part of the basin. The maps and cross sections also show barriers to groundwater movement created by aquitards resulting in areas of apparent isolation/stagnation of concentrated brines within the basin. The distribution of Cl - within the Illinois Basin suggests that the current chemical composition of groundwater and distribution of brines within the basin is dependent on five parameters: (1) presence of bedrock exposures along basin margins; (2) permeability of geologic strata and their distribution relative to one another; (3) presence or absence of major geologic structures; (4) intersection of major waterways with geologic structures, basin margins, and permeable bedrock exposures; and (5) isolation of brines within the basin due to aquitards, inhomogeneous permeability, and, in the case of the deepest part of the basin, brine density effects. © 2017, National Ground Water Association.

  11. Quantifying Modern Recharge and Depletion Rates of the Nubian Aquifer in Egypt

    Science.gov (United States)

    Ahmed, Mohamed; Abdelmohsen, Karem

    2018-02-01

    Egypt is currently seeking additional freshwater resources to support national reclamation projects based mainly on the Nubian aquifer groundwater resources. In this study, temporal (April 2002 to June 2016) Gravity Recovery and Climate Experiment (GRACE)-derived terrestrial water storage (TWSGRACE) along with other relevant datasets was used to monitor and quantify modern recharge and depletion rates of the Nubian aquifer in Egypt (NAE) and investigate the interaction of the NAE with artificial lakes. Results indicate: (1) the NAE is receiving a total recharge of 20.27 ± 1.95 km3 during 4/2002-2/2006 and 4/2008-6/2016 periods, (2) recharge events occur only under excessive precipitation conditions over the Nubian recharge domains and/or under a significant rise in Lake Nasser levels, (3) the NAE is witnessing a groundwater depletion of - 13.45 ± 0.82 km3/year during 3/2006-3/2008 period, (4) the observed groundwater depletion is largely related to exceptional drought conditions and/or normal baseflow recession, and (5) a conjunctive surface water and groundwater management plan needs to be adapted to develop sustainable water resources management in the NAE. Findings demonstrate the use of global monthly TWSGRACE solutions as a practical, informative, and cost-effective approach for monitoring aquifer systems across the globe.

  12. Interactions between deep bedrock aquifers and surface water in function of recharge and topography: a numerical study

    Science.gov (United States)

    Goderniaux, P.; Davy, P.; Le Borgne, T.; Bresciani, E.; Jimenez-Martinez, J.

    2011-12-01

    In crystalline rock regions, such as Brittany (France), important reserves of groundwater into deep fractured aquifers are increasingly used and provide high quality water compared to shallow aquifers which can be subject to agricultural contamination. However, recharge processes of these deep aquifers and interactions with surface water are not yet fully understood. In some areas, intensive pumping is carried out without guarantee of the resource quantity and quality. Understanding these processes is crucial for sustainable management of the resource. In this study, we study how deep groundwater fluxes, pathways, ages, and river-aquifer interactions vary according to recharge. We assume that water flowing from the ground surface is distributed between shallow more permeable layers and deep layers. This repartition mostly depends on recharge rates. With high recharge, groundwater levels are high and subsurface streamlines are relatively short between recharge areas and existing draining rivers, which constitutes a very dense network. Therefore, most of the groundwater fluxes occur through the more permeable shallow layers. With low recharge, groundwater levels are lower, and river and shallow permeable levels are partly disconnected from each other. This induces a general increase of the groundwater streamlines length from the recharge areas to more sporadic discharge areas, and more fluxes occur through the deep layers. Recharge conditions and river-aquifer interactions have changed over the last thousands of years, due to change in precipitation, temperatures, existence of permafrost, etc. They have strongly influenced deep groundwater fluxes and can explain current groundwater age and flux distribution. To study these interactions, a regional-scale finite difference flow model was implemented. The model covers an area of 1400 km 2 , a depth of 1 km, and the topography is characteristic of Brittany. As rivers are mainly fed by groundwater drainage, seepages faces

  13. Surface and subsurface continuous gravimetric monitoring of groundwater recharge processes through the karst vadose zone at Rochefort Cave (Belgium)

    Science.gov (United States)

    Watlet, A.; Van Camp, M. J.; Francis, O.; Poulain, A.; Hallet, V.; Triantafyllou, A.; Delforge, D.; Quinif, Y.; Van Ruymbeke, M.; Kaufmann, O.

    2017-12-01

    Ground-based gravimetry is a non-invasive and integrated tool to characterize hydrological processes in complex environments such as karsts or volcanoes. A problem in ground-based gravity measurements however concerns the lack of sensitivity in the first meters below the topographical surface, added to limited infiltration below the gravimeter building (umbrella effect). Such limitations disappear when measuring underground. Coupling surface and subsurface gravity measurements therefore allow isolating hydrological signals occurring in the zone between the two gravimeters. We present a coupled surface/subsurface continuous gravimetric monitoring of 2 years at the Rochefort Cave Laboratory (Belgium). The gravity record includes surface measurements of a GWR superconducting gravimeter and subsurface measurements of a Micro-g LaCoste gPhone gravimeter, installed in a cave 35 m below the surface station. The recharge of karstic aquifers is extremely complex to model, mostly because karst hydrological systems are composed of strongly heterogeneous flows. Most of the problem comes from the inadequacy of conventional measuring tools to correctly sample such heterogeneous media, and particularly the existence of a duality of flow types infiltrating the vadose zone: from rapid flows via open conduits to slow seepage through porous matrix. Using the surface/subsurface gravity difference, we were able to identify a significant seasonal groundwater recharge within the karst vadose zone. Seasonal or perennial perched reservoirs have already been proven to exist in several karst areas due to the heterogeneity of the porosity and permeability gradient in karstified carbonated rocks. Our gravimetric experiment allows assessing more precisely the recharge processes of such reservoirs. The gravity variations were also compared with surface and in-cave hydrogeological monitoring (i.e. soil moisture, in-cave percolating water discharges, water levels of the saturated zone). Combined

  14. Identifying three-dimensional nested groundwater flow systems in a Tóthian basin

    Science.gov (United States)

    Wang, Xu-Sheng; Wan, Li; Jiang, Xiao-Wei; Li, Hailong; Zhou, Yangxiao; Wang, Junzhi; Ji, Xiaohui

    2017-10-01

    Nested groundwater flow systems have been revealed in Tóth's theory as the structural property of basin-scale groundwater circulation but were only well known with two-dimensional (2D) profile models. The method of searching special streamlines across stagnation points for partitioning flow systems, which has been successfully applied in the 2D models, has never been implemented for three-dimensional (3D) Tóthian basins because of the difficulty in solving the dual stream functions. Alternatively, a new method is developed to investigate 3D nested groundwater flow systems without determination of stagnation points. Connective indices are defined to quantify the connection between individual recharge and discharge zones along streamlines. Groundwater circulation cells (GWCCs) are identified according to the distribution of the connective indices and then grouped into local, intermediate and regional flow systems. This method requires existing solution of the flow velocity vector and is implemented via particle tracking technique. It is applied in a hypothetical 3D Tóthian basin with an analytical solution of the flow field and in a real-world basin with a numerical modeling approach. Different spatial patterns of flow systems compared to 2D profile models are found. The outcrops boundaries of GWCCs on water table may significantly deviate from and are not parallel to the nearby water table divides. Topological network is proposed to represent the linked recharge-discharge zones through closed and open GWCCs. Sensitivity analysis indicates that the development of GWCCs depends on the basin geometry, hydraulic parameters and water table shape.

  15. Linking soil moisture balance and source-responsive models to estimate diffuse and preferential components of groundwater recharge

    Directory of Open Access Journals (Sweden)

    M. O. Cuthbert

    2013-03-01

    Full Text Available Results are presented of a detailed study into the vadose zone and shallow water table hydrodynamics of a field site in Shropshire, UK. A conceptual model is presented and tested using a range of numerical models, including a modified soil moisture balance model (SMBM for estimating groundwater recharge in the presence of both diffuse and preferential flow components. Tensiometry reveals that the loamy sand topsoil wets up via preferential flow and subsequent redistribution of moisture into the soil matrix. Recharge does not occur until near-positive pressures are achieved at the top of the sandy glaciofluvial outwash material that underlies the topsoil, about 1 m above the water table. Once this occurs, very rapid water table rises follow. This threshold behaviour is attributed to the vertical discontinuity in preferential flow pathways due to seasonal ploughing of the topsoil and to a lower permeability plough/iron pan restricting matrix flow between the topsoil and the lower outwash deposits. Although the wetting process in the topsoil is complex, a SMBM is shown to be effective in predicting the initiation of preferential flow from the base of the topsoil into the lower outwash horizon. The rapidity of the response at the water table and a water table rise during the summer period while flow gradients in the unsaturated profile were upward suggest that preferential flow is also occurring within the outwash deposits below the topsoil. A variation of the source-responsive model proposed by Nimmo (2010 is shown to reproduce the observed water table dynamics well in the lower outwash horizon when linked to a SMBM that quantifies the potential recharge from the topsoil. The results reveal new insights into preferential flow processes in cultivated soils and provide a useful and practical approach to accounting for preferential flow in studies of groundwater recharge estimation.

  16. Land subsidence due to groundwater pumping and recharge: considering the particle-deposition effect in ground-source heat-pump engineering

    Science.gov (United States)

    Cui, Xianze; Liu, Quansheng; Zhang, Chengyuan; Huang, Yisheng; Fan, Yong; Wang, Hongxing

    2018-01-01

    With the rapid development and use of ground-source heat-pump (GSHP) systems in China, it has become imperative to research the effects of associated long-term pumping and recharge processes on ground deformation. During groundwater GSHP operation, small particles can be transported and deposited, or they can become detached in the grain skeleton and undergo recombination, possibly causing a change in the ground structure and characteristics. This paper presents a mathematical ground-deformation model that considers particle transportation and deposition in porous media based on the geological characteristics of a dual-structure stratum in Wuhan, eastern China. Thermal effects were taken into consideration because the GSHP technology used involves a device that uses heat from a shallow layer of the ground. The results reveal that particle deposition during the long-term pumping and recharge process has had an impact on ground deformation that has significantly increased over time. In addition, there is a strong correlation between the deformation change (%) and the amount of particle deposition. The position of the maximum deformation change is also the location where most of the particles are deposited, with the deformation change being as high as 43.3%. The analyses also show that flow of groundwater can have an effect on the ground deformation process, but the effect is very weak.

  17. Land subsidence due to groundwater pumping and recharge: considering the particle-deposition effect in ground-source heat-pump engineering

    Science.gov (United States)

    Cui, Xianze; Liu, Quansheng; Zhang, Chengyuan; Huang, Yisheng; Fan, Yong; Wang, Hongxing

    2018-05-01

    With the rapid development and use of ground-source heat-pump (GSHP) systems in China, it has become imperative to research the effects of associated long-term pumping and recharge processes on ground deformation. During groundwater GSHP operation, small particles can be transported and deposited, or they can become detached in the grain skeleton and undergo recombination, possibly causing a change in the ground structure and characteristics. This paper presents a mathematical ground-deformation model that considers particle transportation and deposition in porous media based on the geological characteristics of a dual-structure stratum in Wuhan, eastern China. Thermal effects were taken into consideration because the GSHP technology used involves a device that uses heat from a shallow layer of the ground. The results reveal that particle deposition during the long-term pumping and recharge process has had an impact on ground deformation that has significantly increased over time. In addition, there is a strong correlation between the deformation change (%) and the amount of particle deposition. The position of the maximum deformation change is also the location where most of the particles are deposited, with the deformation change being as high as 43.3%. The analyses also show that flow of groundwater can have an effect on the ground deformation process, but the effect is very weak.

  18. Groundwater problems studies in the Thar desert, India, using isotope techniques

    International Nuclear Information System (INIS)

    Navada, S.V.

    1999-01-01

    In groundwater management, particularly in arid regions like western Rajasthan, it is important to know the presence of modern recharge and to estimate the recharge rate to avoid over-exploitation of the groundwater resource. Isotopes can help to identify modern recharge and to estimate recharge rate to the aquifer. If modern recharge is absent, groundwater dating using radiocarbon could help to identify old groundwater or paleowaters. A number of isotope studies carried out in arid zones (particularly in the Sahara) have shown that the deep groundwater is generally very old. From these studies it was concluded that episodic large scale recharge corresponding to humid phases or pluvials occurred in these arid areas. The paper reviews our experiences on the application of isotope techniques in understanding groundwater recharge process in and western Rajasthan

  19. Application, difficulties and perspectives of artificial recharge of groundwater in Spain; Aplicacion, dificultades y perspectivas de la recarga artificial de acuiferos en Espana

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Paricio, A.

    2001-07-01

    Artificial recharge of groundwater is an extremely useful techniques for the management of water resources. This is why artificial recharge is viewed as an essential component of water supply systems in some countries. Because spreading scientific-technical knowledge is a key to combat misconceptions, this paper describes the results obtained in an European project, where the author participated as representative of the Technical University of Catalonia. the variety of topics addressed by this project and the status of artificial recharge in other regions contrast notoriously with the current situation in Spain, as explained in the paper. Nowadays, there are symptoms of improvement, but it is still necessary a conceptual change. This requires more imaginative plants that take advantage of treated waste-water and storm water, as well as their integration with alternative measures, such as desalination, reuse, optimization of water distribution and irrigation networks and the management of water demand. (Author) 25 refs.

  20. Response of deep groundwater to land use change in desert basins of the Trans-Pecos region, Texas, USA: Effects on infiltration, recharge, and nitrogen fluxes

    Science.gov (United States)

    Robertson, Wendy Marie; Böhlke, John Karl; Sharp, John M.

    2017-01-01

    Quantifying the effects of anthropogenic processes on groundwater in arid regions can be complicated by thick unsaturated zones with long transit times. Human activities can alter water and nutrient fluxes, but their impact on groundwater is not always clear. This study of basins in the Trans-Pecos region of Texas links anthropogenic land use and vegetation change with alterations to unsaturated zone fluxes and regional increases in basin groundwater NO3−concentrations. Median increases in groundwater NO3− (by 0.7–0.9 mg-N/l over periods ranging from 10 to 50+ years) occurred despite low precipitation (220–360 mm/year), high potential evapotranspiration (~1570 mm/year), and thick unsaturated zones (10–150+ m). Recent model simulations indicate net infiltration and groundwater recharge can occur beneath Trans-Pecos basin floors, and may have increased due to irrigation and vegetation change. These processes were investigated further with chemical and isotopic data from groundwater and unsaturated zone cores. Some unsaturated zone solute profiles indicate flushing of natural salt accumulations has occurred. Results are consistent with human-influenced flushing of naturally accumulated unsaturated zone nitrogen as an important source of NO3− to the groundwater. Regional mass balance calculations indicate the mass of natural unsaturated zone NO3− (122–910 kg-N/ha) was sufficient to cause the observed groundwater NO3− increases, especially if augmented locally with the addition of fertilizer N. Groundwater NO3− trends can be explained by small volumes of high NO3− modern recharge mixed with larger volumes of older groundwater in wells. This study illustrates the importance of combining long-term monitoring and targeted process studies to improve understanding of human impacts on recharge and nutrient cycling in arid regions, which are vulnerable to the effects of climate change and increasing human reliance on dryland ecosystems.

  1. Using isotopes for design and monitoring of artificial recharge systems

    Science.gov (United States)

    Contributors: Hendriksson, N.; Kulongoski, J.T.; Massmann, G.; Newman, B.

    2013-01-01

    Over the past years, the IAEA has provided support to a number of Member States engaged in the implementation of hydrological projects dealing with the design and monitoring of artificial recharge ( A R ) systems, primarily situated in arid and semiarid regions. AR is defined as any engineered system designed to introduce water to, and store water in, underlying aquifers. Aquifer storage and recovery (ASR) is a specific type of AR used with the purpose of increasing groundwater resources. Different water management strategies have been tested under various geographical, hydrological and climatic regimes. However, the success of such schemes cannot easily be predicted, since many variables need to be taken into account in the early stages of every AR project.

  2. Isotope Hydrology Investigation of Zonguldak And Province Groundwater

    International Nuclear Information System (INIS)

    Erduran, B.; Toerk, K.; Oektue, G.

    2002-01-01

    The most important coal area of Turkey is situated in Zonguldak and province. The coal series occurred during Westfalien (Carboniferous) are lower-bounded by Visean aged karstic limestones and upper-bounded by Aptian-Barremian aged karstic limestones. The isotope hydrology, which consists one of the studies dealed with karst hydrogeology, was held to determine the groundwater relations between the karstic limestones adjacent to the coal layers located in the Zonguldak coal mine areas. Environmental isotope samples were collected in the basin during 1994 - 1995 period, from the surface and groundwater. Deuterium ( 2 H), Oxygen 18 ( 18 O) and Tritium ( 3 H) analysis were carried out on the samples. Recharge elevation, water origin and transit time of the groundwater system were determined with the evaluation of the analysis results. Waters encountered in the area are of marine origined rainfall, recharging at an elevation of 400-500 meters and consisting of shallow and deep circulation systems. Groundwater that intruding the coal mine galleries, have a short flow period and are recharged from recent precipitations

  3. Annotated bibliography on artificial recharge of ground water, 1955-67

    Science.gov (United States)

    Signor, Donald C.; Growitz, Douglas J.; Kam, William

    1970-01-01

    Artificial ground-water recharge has become more important as water use by agriculture, industry, and municipalities increases. Water management agencies are increasingly interested in potential use of recharge for pollution abatement, waste-water disposal, and re-use and reclamation of locally available supplies. Research projects and theoretical analyses of operational recharge systems show increased scientific emphasis on the practice. Overall ground-water basin management systems generally now contain considerations of artificial recharge, whether by direct or indirect methods. Artificial ground-water recharge is a means of conserving surface runoff for future use in places where it would otherwise be lost, of protecting ground-water basins from salt-water encroachment along coastal areas, and of storing and distributing imported water. The biblio-graphy emphasizes technology; however, annotations of articles on waste-water reclamation, ground-water management and ground-water basin management are included. Subjects closely related to artificial recharge, including colloidal flow through porous media, field or laboratory instrumentation, and waste disposal by deep well injection are included where they specifically relate to potential recharge problems. Where almost the same material has been published in several journals, all references are included on the assumption that some publications may be more readily available to interested persons than others. Other publications, especially those of foreign literature, provided abstracts that were used freely as time limitations precluded obtaining and annotating all materials. Abstracts taken from published sources are noted. These are: "Abstracts of North American Geology," U.S. Department of the Interior, Geological Survey; "Abstracts of Recent Published Material on Foil and Water Conservation," ARS-41 series, Agricultural F.esearch Service, U.S. Department of Agriculture; "Water and1 Water

  4. Isotopes and Sustainability of the Shallow Groundwater System in Spring and Snake Valleys, Eastern White Pine County, Nevada

    Science.gov (United States)

    Acheampong, S. Y.

    2007-12-01

    A critical component to managing water resources is understanding the source of ground water that is extracted from a well. Detail information on the source of recharge and the age of groundwater is thus vital for the proper assessment, development, management, and monitoring of the groundwater resources in an area. Great differences in the isotopic composition of groundwater in a basin and the basin precipitation imply that the groundwater in the basin originates from a source outside the basin or is recharged under different climatic conditions. The stable isotopes of oxygen and hydrogen in precipitation were compared with the isotopic composition of water from wells, springs, and creeks to evaluate the source of the shallow groundwater recharge in Spring and Snake Valleys, Nevada, as part of an evaluation of the water resources in the area. Delta deuterium and delta oxygen-18 composition of springs, wells, creeks, and precipitation in Spring and Snake Valleys show that groundwater recharge occurs primarily from winter precipitation in the surrounding mountains. The carbon-14 content of the groundwater ranged from 30 to 95 percent modern carbon (pmc). Twenty two of the thirty samples had carbon-14 values of greater than 50 pmc. The relatively high carbon-14 values suggest that groundwater in the area is recharged by modern precipitation and the waters have rapid travel times. Total dissolved solids content of the samples outside the playa areas are generally low, and suggests that the water has a relatively short travel time between the recharge areas and sample sites. The presence of tritium in some of the springs and wells also indicate that groundwater mixes with post 1952 precipitation. Hydrogen bomb tests which began in 1952 in the northern hemisphere added large amounts of tritium to the atmosphere and reached a peak in 1963. The stable isotopic composition, the high carbon-14 activities, and the presence of tritium, show that the shallow groundwater in

  5. Assessment of groundwater quality using geographical information system (GIS), at north-east Cairo, Egypt.

    Science.gov (United States)

    El-Shahat, M F; Sadek, M A; Mostafa, W M; Hagagg, K H

    2016-04-01

    The present investigation has been conducted to delineate the hydrogeochemical and environmental factors that control the water quality of the groundwater resources in the north-east of Cairo. A complementary approach based on hydrogeochemistry and a geographical information system (GIS) based protectability index has been employed for conducting this work. The results from the chemical analysis revealed that the groundwater of the Quaternary aquifer is less saline than that of the Miocene aquifer and the main factors that control the groundwater salinity in the studied area are primarily related to the genesis of the original recharging water modified after by leaching, dissolution, cation exchange, and fertilizer leachate. The computed groundwater quality index (WQI) falls into two categories: fair for almost all the Miocene groundwater samples, while the Quaternary groundwater samples are all have a good quality. The retarded flow and non-replenishment of the Miocene aquifer compared to the renewable active recharge of the Quaternary aquifer can explain this variation of WQI. The index and overlay approach exemplified by the DUPIT index has been used to investigate the protectability of the study aquifers against diffuse pollutants. Three categories (highly protectable less vulnerable, moderately protectable moderately vulnerable and less protectable highly vulnerable) have been determined and areally mapped.

  6. Groundwater recharge through wells in open loop geothermal system: problems and solutions - part 1

    Directory of Open Access Journals (Sweden)

    Giovanni Pietro Beretta

    2017-07-01

    Full Text Available In the two parts of this article, the problems related to the management of water wells as part of a low-enthalpy geothermal power plant by means of heat pumps (open loop system are described. In many cases, in absence of discharge in surface water and/or to ensure the conservation of the resource from a quantitative point of view, a doublet system constituted by a pumping and a recharge well is provided. The clogging phenomenon often occurs in this kind of plant, affecting wells with different functions and different thermal potential related to water withdrawal and reinjection into the ground. This phenomenon is due to the presence of air bubbles, suspended solids, bacterial growth and to the chemical-physical reactions that are described in the text. Besides acknowledging the activities for recharge wells management to avoid the fracturing of the drain and the cementation, is also suggested the procedure of in situ tests that are used to properly determine the optimal well discharge, which determines the efficiency and effectiveness of the geothermal system and its economic performance.It is finally shown a regional regulation on the water quality used in an open loop.

  7. Assessment of virus removal by managed aquifer recharge at three full-scale operations.

    Science.gov (United States)

    Betancourt, Walter Q; Kitajima, Masaaki; Wing, Alexandre D; Regnery, Julia; Drewes, Jörg E; Pepper, Ian L; Gerba, Charles P

    2014-01-01

    Managed aquifer recharge (MAR) systems such as riverbank filtration and soil-aquifer treatment all involve the use of natural subsurface systems to improve the quality of recharged water (i.e. surface water, stormwater, reclaimed water) before reuse. During MAR, water is either infiltrated via basins, subsurface injected or abstracted from wells adjacent to rivers. The goal of this study was to assess the removal of selected enteric viruses and a potential surrogate for virus removal at three full-scale MAR systems located in different regions of the United States (Arizona, Colorado, and California). Samples of source water (i.e., river water receiving treated wastewater and reclaimed water) before recharge and recovered groundwater at all three sites were tested for adenoviruses, enteroviruses, Aichi viruses and pepper mild mottle virus (PMMoV) by quantitative polymerase chain reaction (qPCR). Samples of groundwater positive for any virus were also tested for the presence of infectious virus by cell culture. PMMoV was the most commonly detected virus in the groundwater samples. Infectious enteric viruses (reovirus) were only detected in one groundwater sample with a subsurface residence time of 5 days. The results suggested that in groundwater with a residence time of greater than 14 days all of the viruses are removed below detection indicating a 1 to greater than 5 log removal depending upon the type of virus. Given its behavior, PMMoV may be suitable to serve as a conservative tracer of enteric virus removal in managed aquifer treatment systems.

  8. The Guarani Aquifer System: estimation of recharge along the Uruguay-Brazil border

    Science.gov (United States)

    Gómez, Andrea A.; Rodríguez, Leticia B.; Vives, Luis S.

    2010-11-01

    The cities of Rivera and Santana do Livramento are located on the outcropping area of the sandstone Guarani Aquifer on the Brazil-Uruguay border, where the aquifer is being increasingly exploited. Therefore, recharge estimates are needed to address sustainability. First, a conceptual model of the area was developed. A multilayer, heterogeneous and anisotropic groundwater-flow model was built to validate the conceptual model and to estimate recharge. A field campaign was conducted to collect water samples and monitor water levels used for model calibration. Field data revealed that there exists vertical gradients between confining basalts and underlying sandstones, suggesting basalts could indirectly recharge sandstone in fractured areas. Simulated downward flow between them was a small amount within the global water budget. Calibrated recharge rates over basalts and over outcropping sandstones were 1.3 and 8.1% of mean annual precipitation, respectively. A big portion of sandstone recharge would be drained by streams. The application of a water balance yielded a recharge of 8.5% of average annual precipitation. The numerical model and the water balance yielded similar recharge values consistent with determinations from previous authors in the area and other regions of the aquifer, providing an upper bound for recharge in this transboundary aquifer.

  9. Environmental isotope study of groundwater systems in the Republic of Djibouti

    International Nuclear Information System (INIS)

    Fontes, J.Ch.; Saliege, J.F.; Zuppi, G.M.; Pouchan, P.

    1980-01-01

    Environmental isotopes and hydrogeochemistry are being used to shed new light on the occurrence of present-day recharge and on the origin of groundwater systems in the Republic of Djibouti. Furthermore, an attempt is also being made to evaluate palaeohydrological conditions during the past 6000 years. From stable isotope data which lie along a correlation line at a slope of 8 in the diagram delta 2 H-delta 18 O, it can be concluded that recharge occurs by rapid seepage in fractured rocks without evaporation. Some waters from hot springs show an oxygen shift, indicating the occurrence of an exchange process with rocks at high temperatures. The following conclusions can be reached from tritium and 14 C content of waters. Groundwaters can be divided into two groups: one deriving from recent recharge (last five or six years) corresponding to water with rather fast circulations in fractured media; and a second group, pre-bomb recharged corresponding to water with low flow rates in porous media. Only one sample (Yoboki) seems to derive from about 10-year-old recharge. In the case of Abhe hot spring, a 14 C age of about 1200 years may be evaluated. The calcite concretions of the Abhe Lake Basin are believed to have formed as a result of the mixing of lake water (sodium-carbonate type) with groundwater (sodium-chloride, calcium-sulphate type). From the 13 C and 14 C content it appears that the dissolved carbon of present-day lake water is in, or close to, equilibrium with the atmosphere. Consequently, it is assumed that such was also the case during the whole Holocene. The 18 O content of palaeolake water, evaluated from the calcite isotopic composition with the palaeo-temperature equation, was originally more negative than the present one. This is interpreted as due to the fact that the Holocene lake was fed by large floods and that significant seepage occurred through the lake bottom with a consequent reduction of the evaporation effects. (author)

  10. Groundwater flow pattern in the Ruataniwha Plains as derived from the isotope and chemistry signature of the water

    International Nuclear Information System (INIS)

    Morgenstern, U.; van der Raaij, R.; Baalousha, H.

    2012-01-01

    The Ruataniwha Basin is situated in the upper Tukituki catchment, approximately 70 km south west of Napier City. The boundaries of the Ruataniwha Basin are the foothills of the Ruahine Range in the west, Turiri Range and Raukawa Range in the east and rolling hills in the north. The Ruataniwha Plains groundwater system is a multi-layered aquifer system that has a complex hydrogeological setting, as the plains evolved in response to sea-level changes, tectonic activity, and geomorphic processes. Aquifers in the basin occur in gravel, sandstone, pumice and limestone strata within a basin structure. In this study, groundwater samples have been collected for hydrochemistry, dissolved gases, and age tracer analysis. Tracer results were interpreted in terms of groundwater recharge source and rate, groundwater age, changes in groundwater source, and the homogeneity of the aquifers. This helps with conceptual understanding of Ruataniwha Basin groundwater flow patterns, and provides data for calibration of a numerical surface-groundwater flow model. Most water samples across the Ruataniwha Basin contain old water, with a mean residence time (MRT) > 25 years. The old age of most of the waters indicates that these groundwaters are not directly linked to surface water. In the south eastern part of the basin, all groundwater samples are old (>100 years), indicating slow movement of groundwater and slow recharge, consistent with the geology of the area. In the south eastern part of the basin the geologic units have low permeability. The age depth relationship is biased by upwelling groundwater and reflects the closed nature of the basin. The average vertical flow velocity indicates a recharge rate of 0.19 m/y. Four wells in the vicinity of the lower Waipawa River show excellent age-depth relationships, indicating absence of disturbance by groundwater upwelling. The recharge rate there of 0.42 m/y is substantially higher than in the other parts of the basin, indicating river

  11. Recent and ancient recharge deciphered by multi-dating tracer technique

    Science.gov (United States)

    Dogramaci, Shawan; Cook, Peter; Mccallum, Jimes; Purtchert, Roland

    2017-04-01

    Determining groundwater residence time from environmental tracer concentrations obtained from open bores or long screened intervals is fraught with difficulty because the sampled water represents variety of ages. Information on the distribution of groundwater age is commonly obtained by measuring more than one tracer. We examined the use of the multi-tracer technique representing different time frames (39Ar, 85Kr, 14C, 3H, CFC 11- CFC-12 CFC-113, SF6 and Cl,) to decipher the groundwater ages sampled from long screened bores in a regional aquifer in the Pilbara region of northwest Australia. We then applied a technique that assumes limited details of the form of the age distribution. Tracer concentrations suggest that groundwater samples are a mixture of young and old water - the former is inferred to represent localised recharge from an adjacent creek, and the latter to be diffuse recharge. Using our method, we were able to identify distinct age components in the groundwater. The results suggest the presence of four distinct age groups; zero and 20 years, 50 to 100 years, 100 to 600 years and approximately 1000 years old. These relatively high recharge events were consistent with local recharge sources (50-100 years) and confirmed by palaeo-climate record obtained from lake sediments. We found that although the ages of these components were well constrained, the relative proportions of each component was highly sensitive to errors of environmental tracer data. Our results show that the method we implemented can identify distinct age groups in groundwater samples without prior knowledge of the age distribution. The presence of distinct recharge times gives insight into groundwater flow conditions over long periods of time.

  12. Groundwater discharge to the Mississippi River and groundwater balances for the Interstate 94 Corridor surficial aquifer, Clearwater to Elk River, Minnesota, 2012–14

    Science.gov (United States)

    Smith, Erik A.; Lorenz, David L.; Kessler, Erich W.; Berg, Andrew M.; Sanocki, Chris A.

    2017-12-13

    The Interstate 94 Corridor has been identified as 1 of 16 Minnesota groundwater areas of concern because of its limited available groundwater resources. The U.S. Geological Survey, in cooperation with the Minnesota Department of Natural Resources, completed six seasonal and annual groundwater balances for parts of the Interstate 94 Corridor surficial aquifer to better understand its long-term (next several decades) sustainability. A high-precision Mississippi River groundwater discharge measurement of 5.23 cubic feet per second per mile was completed at low-flow conditions to better inform these groundwater balances. The recharge calculation methods RISE program and Soil-Water-Balance model were used to inform the groundwater balances. For the RISE-derived recharge estimates, the range was from 3.30 to 11.91 inches per year; for the SWB-derived recharge estimates, the range was from 5.23 to 17.06 inches per year.Calculated groundwater discharges ranged from 1.45 to 5.06 cubic feet per second per mile, a ratio of 27.7 to 96.4 percent of the measured groundwater discharge. Ratios of groundwater pumping to total recharge ranged from 8.6 to 97.2 percent, with the longer-term groundwater balances ranging from 12.9 to 19 percent. Overall, this study focused on the surficial aquifer system and its interactions with the Mississippi River. During the study period (October 1, 2012, through November 30, 2014), six synoptic measurements, along with continuous groundwater hydrographs, rainfall records, and a compilation of the pertinent irrigation data, establishes the framework for future groundwater modeling efforts.

  13. Oxygen, hydrogen, and helium isotopes for investigating groundwater systems of the Cape Verde Islands, West Africa

    Science.gov (United States)

    Heilweil, V.M.; Solomon, K.D.; Gingerich, S.B.; Verstraeten, Ingrid M.

    2009-01-01

    Stable isotopes (??18O, ??2H), tritium (3H), and helium isotopes (3He, 4He) were used for evaluating groundwater recharge sources, flow paths, and residence times of three watersheds in the Cape Verde Islands (West Africa). Stable isotopes indicate the predominance of high-elevation precipitation that undergoes little evaporation prior to groundwater recharge. In contrast to other active oceanic hotspots, environmental tracers show that deep geothermal circulation does not strongly affect groundwater. Low tritium concentrations at seven groundwater sites indicate groundwater residence times of more than 50 years. Higher tritium values at other sites suggest some recent recharge. High 4He and 3He/4He ratios precluded 3H/3He dating at six sites. These high 3He/4He ratios (R/Ra values of up to 8.3) are consistent with reported mantle derived helium of oceanic island basalts in Cape Verde and provided end-member constraints for improved dating at seven other locations. Tritium and 3H/3He dating shows that S??o Nicolau Island's Ribeira Faj?? Basin has groundwater residence times of more than 50 years, whereas Fogo Island's Mosteiros Basin and Santo Ant??o Island's Ribeira Paul Basin contain a mixture of young and old groundwater. Young ages at selected sites within these two basins indicate local recharge and potential groundwater susceptibility to surface contamination and/or salt-water intrusion. ?? Springer-Verlag 2009.

  14. Effects of changes in pumping on regional groundwater-flow paths, 2005 and 2010, and areas contributing recharge to discharging wells, 1990–2010, in the vicinity of North Penn Area 7 Superfund site, Montgomery County, Pennsylvania

    Science.gov (United States)

    Senior, Lisa A.; Goode, Daniel J.

    2017-06-06

    A previously developed regional groundwater flow model was used to simulate the effects of changes in pumping rates on groundwater-flow paths and extent of recharge discharging to wells for a contaminated fractured bedrock aquifer in southeastern Pennsylvania. Groundwater in the vicinity of the North Penn Area 7 Superfund site, Montgomery County, Pennsylvania, was found to be contaminated with organic compounds, such as trichloroethylene (TCE), in 1979. At the time contamination was discovered, groundwater from the underlying fractured bedrock (shale) aquifer was the main source of supply for public drinking water and industrial use. As part of technical support to the U.S. Environmental Protection Agency (EPA) during the Remedial Investigation of the North Penn Area 7 Superfund site from 2000 to 2005, the U.S. Geological Survey (USGS) developed a model of regional groundwater flow to describe changes in groundwater flow and contaminant directions as a result of changes in pumping. Subsequently, large decreases in TCE concentrations (as much as 400 micrograms per liter) were measured in groundwater samples collected by the EPA from selected wells in 2010 compared to 2005‒06 concentrations.To provide insight on the fate of potentially contaminated groundwater during the period of generally decreasing pumping rates from 1990 to 2010, steady-state simulations were run using the previously developed groundwater-flow model for two conditions prior to extensive remediation, 1990 and 2000, two conditions subsequent to some remediation 2005 and 2010, and a No Pumping case, representing pre-development or cessation of pumping conditions. The model was used to (1) quantify the amount of recharge, including potentially contaminated recharge from sources near the land surface, that discharged to wells or streams and (2) delineate the areas contributing recharge that discharged to wells or streams for the five conditions.In all simulations, groundwater divides differed from

  15. Investigation of the Present Recharge Rate and Recharge Origins in the Disi Sandstone Aquifer in Southern Jordan

    International Nuclear Information System (INIS)

    Kilani, S.F.

    2003-01-01

    This study presents a thorough investigation of recharge origins of the strategic Disi sandstone aquifer in southern Jordan. This aquifer is of substantial potential and huge extension most of which lies in Saudi Arabia. Disi groundwater infiltrated in the ground thousands of years ago and is not currently being replenished, therefore crucial management for this resource is very important. This aquifer is foreseen to provide 100 MCM/a of high quality drinking water to the Capital Amman in addition to the current use of about 60 MCM/a for agricultural activities in the area and to meet the water demand in the port of Aqaba. Origins and amount of recharge to groundwater is one critical aspect in resource management. A study to estimate recharge rate was conducted in the Quaternary sediments and sandstone's of Al Quwayra in southern Jordan where the average rainfall is less than 70 mm per year. Environmental chloride, deuterium and nitrate in the sand profiles in the vadose zone were the study tools. The study showed that recharge if present is a result of severe infrequent storm events and that the aquifer does not receive significant direct recharge from rain. The pollutant profiles in the unsaturated zone might give chronology of the recharge history

  16. Estimation of Net Groundwater Recharge Using Natural Drawdown Events in Subtropical Isolated Wetland Ecosystems

    Science.gov (United States)

    Perkins, D. B.; Min, J.; Jawitz, J. W.

    2008-12-01

    Restoration of ditched and drained wetlands in the Lake Okeechobee basin, Florida, USA is currently under study for possible amelioration of anthropogenic phosphorus enrichment of the lake. To date most research in this area has focused on the biogeochemical role of these wetlands. Here we focus on the dynamic hydrology of these systems and the resulting control on biogeochemical cycling. Four depressional wetlands in the basin were monitored for approximately three years to understand the interaction between wetland surface water and adjacent upland groundwater system. A coupled hydrologic-biogeochemical model was created to evaluate restoration scenarios. Determining wetland-scale hydraulic conductivity was an important aspect of the hydrologic model. Based on natural drawdown events observed at wetland-upland well pairs, hydraulic conductivities of top sandy soil layers surrounding the isolated wetlands were calculated using the Dupuit equation under a constrained water budget framework. The drawdown-based hydraulic conductivity estimates of 1.1 to 18.7 m/d (geometric mean of 4.8 m/d) were about three times greater than slug test- based values (1.5 ± 1.1 m/d), which is consistent with scale-dependent expectations. Model-based net groundwater recharge rate at each depressional wetland was predicted based on the estimated hydraulic conductivities, which corresponded to 50 to 72% of rainfall in the same period. These variances appeared to be due to the relative difference of ditch bottom elevation controlling the surface runoff as well as the spatial heterogeneity of the sandy aquifer. Results from this study have implications for nutrient loads to Lake Okeechobee via groundwater as well as water quality monitoring and management strategies aimed to reduce solute export (especially P) from the upstream catchment area to Lake Okeechobee.

  17. Groundwater flow and water budget in the surficial and Floridan aquifer systems in east-central Florida

    Science.gov (United States)

    Sepulveda, Nicasio; Tiedeman, Claire; O'Reilly, Andrew M.; Davis, Jeffrey B.; Burger, Patrick

    2012-01-01

    A numerical transient model of the surficial and Floridan aquifer systems in east-central Florida was developed to (1) increase the understanding of water exchanges between the surficial and the Floridan aquifer systems, (2) assess the recharge rates to the surficial aquifer system from infiltration through the unsaturated zone and (3) obtain a simulation tool that could be used by water-resource managers to assess the impact of changes in groundwater withdrawals on spring flows and on the potentiometric surfaces of the hydrogeologic units composing the Floridan aquifer system. The hydrogeology of east-central Florida was evaluated and used to develop and calibrate the groundwater flow model, which simulates the regional fresh groundwater flow system. The U.S. Geological Survey three-dimensional groundwater flow model, MODFLOW-2005, was used to simulate transient groundwater flow in the surficial, intermediate, and Floridan aquifer systems from 1995 to 2006. The East-Central Florida Transient model encompasses an actively simulated area of about 9,000 square miles. Although the model includes surficial processes-rainfall, irrigation, evapotranspiration (ET), runoff, infiltration, lake water levels, and stream water levels and flows-its primary purpose is to characterize and refine the understanding of groundwater flow in the Floridan aquifer system. Model-independent estimates of the partitioning of rainfall into ET, streamflow, and aquifer recharge are provided from a water-budget analysis of the surficial aquifer system. The interaction of the groundwater flow system with the surface environment was simulated using the Green-Ampt infiltration method and the MODFLOW-2005 Unsaturated-Zone Flow, Lake, and Streamflow-Routing Packages. The model is intended to simulate the part of the groundwater system that contains freshwater. The bottom and lateral boundaries of the model were established at the estimated depths where the chloride concentration is 5,000 milligrams

  18. Subsurface thermal regime to delineate the paleo-groundwater flow system in an arid area, Al Kufra, Libya

    Directory of Open Access Journals (Sweden)

    Zenhom El-Said Salem

    2016-12-01

    Full Text Available The purpose of this study was to understand the groundwater flow system in Al Kufra basin, Libya, as a case study of arid areas using subsurface temperature. The temperature-depth profiles and water levels were measured in eight boreholes in the area. Well 6 is considered a recharge type profile with low geothermal gradient (0.0068 °C/m and an estimated paleo-temperature around 19.5 °C. The other profiles are of discharge type with higher geothermal gradient (0.0133 to 0.0166 °C/m. The constructed horizontal 2D distribution maps of the hydraulic heads and the subsurface temperature measurements reveal that the main recharge area is located to the south with low temperature while the main discharge area is located to the north with higher temperature. Vertical 2D distribution maps show that location of well 4 has low hydraulic heads and higher temperature indicating that the fault defined in the area may have affected the groundwater flow system. The estimated groundwater flux ranges from 0.001 to 0.1 mm/day for the recharge area and from −0.3 to −0.7 mm/day in average in the discharge area.

  19. Risk mapping of NO/sub 3/-N contamination on groundwater under intensive rice-based cropping systems in the Philippines

    International Nuclear Information System (INIS)

    Pascual, C.M.; Baga, M.C.S.; Valencia, D.P.

    2005-01-01

    The groundwater resources in a 265 ha watershed of highly diversified and intensive rice-based environment was endangered to NO/sub 3/-N contamination with spatial degree of influence and temporal vulnerability risks as affected by intensive cropping systems with application of high N-fertilizer and judicious use of groundwater for irrigation. Such nitrate contamination levels are above the World Health Organization's maximum contamination level of 10 ppm for drinking water. Tree-joining, complete cluster analysis of monthly groundwater depths on observation wells revealed three distinct groups of wells differentiated by groundwater depths. Planting of nitrate catch crops such as legumes to reduce groundwater contamination and vigorous information dissemination on ill-effects of high NO/sub 3/-N, as well as groundwater recharging were considered to reduce contamination. However, the groundwater extraction for irrigation is still sustainable due to natural recharging of rainfall and hydraulic connections from surface water along rivers and creeks. The combined-use of GIS and GPS proved useful for spatial and temporal risk mapping assessment on groundwater NO/sub 3/-N vulnerability among other geo-referenced attributes of groundwater and other environmental considerations at the study site. Such systems analysis tools can be used by planners, researchers, extension workers, students and farmers for other sustainable development and environmental risk mapping, assessment, extrapolation analysis and strategic planning of sustainable development of the environment. (author)

  20. Simulation of the regional groundwater-flow system of the Menominee Indian Reservation, Wisconsin

    Science.gov (United States)

    Juckem, Paul F.; Dunning, Charles P.

    2015-01-01

    A regional, two-dimensional, steady-state groundwater-flow model was developed to simulate the groundwater-flow system and groundwater/surface-water interactions within the Menominee Indian Reservation. The model was developed by the U.S. Geological Survey (USGS), in cooperation with the Menominee Indian Tribe of Wisconsin, to contribute to the fundamental understanding of the region’s hydrogeology. The objectives of the regional model were to improve understanding of the groundwater-flow system, including groundwater/surface-water interactions, and to develop a tool suitable for evaluating the effects of potential regional water-management programs. The computer code GFLOW was used because of the ease with which the model can simulate groundwater/surface-water interactions, provide a framework for simulating regional groundwater-flow systems, and be refined in a stepwise fashion to incorporate new data and simulate groundwater-flow patterns at multiple scales. Simulations made with the regional model reproduce groundwater levels and stream base flows representative of recent conditions (1970–2013) and illustrate groundwater-flow patterns with maps of (1) the simulated water table and groundwater-flow directions, (2) probabilistic areas contributing recharge to high-capacity pumped wells, and (3) estimation of the extent of infiltrated wastewater from treatment lagoons.

  1. Chemical Evolution of Groundwater Near a Sinkhole Lake, Northern Florida: 1. Flow Patterns, Age of Groundwater, and Influence of Lake Water Leakage

    Science.gov (United States)

    Katz, Brian G.; Lee, Terrie M.; Plummer, L. Niel; Busenberg, Eurybiades

    1995-06-01

    Leakage from sinkhole lakes significantly influences recharge to the Upper Floridan aquifer in poorly confined sediments in northern Florida. Environmental isotopes (oxygen 18, deuterium, and tritium), chlorofluorocarbons (CFCs: CFC-11, CCl3F; CFC-12, CCl2F2; and CFC-113, C2Cl3F3), and solute tracers were used to investigate groundwater flow patterns near Lake Barco, a seepage lake in a mantled karst setting in northern Florida. Stable isotope data indicated that the groundwater downgradient from the lake contained 11-67% lake water leakage, with a limit of detection of lake water in groundwater of 4.3%. The mixing fractions of lake water leakage, which passed through organic-rich sediments in the lake bottom, were directly proportional to the observed methane concentrations and increased with depth in the groundwater flow system. In aerobic groundwater upgradient from Lake Barco, CFC-modeled recharge dates ranged from 1987 near the water table to the mid 1970s for water collected at a depth of 30 m below the water table. CFC-modeled recharge dates (based on CFC-12) for anaerobic groundwater downgradient from the lake ranged from the late 1950s to the mid 1970s and were consistent with tritium data. CFC-modeled recharge dates based on CFC-11 indicated preferential microbial degradation in anoxic waters. Vertical hydraulic conductivities, calculated using CFC-12 modeled recharge dates and Darcy's law, were 0.17, 0.033, and 0.019 m/d for the surficial aquifer, intermediate confining unit, and lake sediments, respectively. These conductivities agreed closely with those used in the calibration of a three-dimensional groundwater flow model for transient and steady state flow conditions.

  2. Geostatistical estimates of future recharge for the Death Valley region

    International Nuclear Information System (INIS)

    Hevesi, J.A.; Flint, A.L.

    1998-01-01

    Spatially distributed estimates of regional ground water recharge rates under both current and potential future climates are needed to evaluate a potential geologic repository for high-level nuclear waste at Yucca Mountain, Nevada, which is located within the Death Valley ground-water region (DVGWR). Determining the spatial distribution of recharge is important for regional saturated-zone ground-water flow models. In the southern Nevada region, the Maxey-Eakin method has been used for estimating recharge based on average annual precipitation. Although this method does not directly account for a variety of location-specific factors which control recharge (such as bedrock permeability, soil cover, and net radiation), precipitation is the primary factor that controls in the region. Estimates of recharge obtained by using the Maxey-Eakin method are comparable to estimates of recharge obtained by using chloride balance studies. The authors consider the Maxey-Eakin approach as a relatively simple method of obtaining preliminary estimates of recharge on a regional scale

  3. In-situ remediation of brine impacted soils and groundwater using hydraulic fracturing, desalinization and recharge wells

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, C. [Wiebe Environmental Services Inc., Calgary, AB (Canada); Ratiu, I. [GeoGrid Environmental Inc., Calgary, AB (Canada)

    2006-07-01

    This conference presentation focused on the in-stu remediation of brine impacted soils and groundwater using hydraulic fracturing, desalinization and recharge wells. A former oil battery was established in the 1940s, decommissioned in the late 1960s with a reclamation certificate issued in 1972. The land owner reported poor vegetative growth in the former battery area. The purpose of the study was to investigate the cause of poor growth and delineate contaminants of concern and to remediate impacted soil and groundwater associated with the former battery site. The investigation involved agrological, geophysical and hydrogeological investigation into the extent of anthropogenic impacts as well as the development of remediation options and plans to deal with issues of concern. The presentation provided the results of the investigation, options identified, and discussed limitation on salt remediation and treatment of saline soils. Other topics included hydraulic fracturing, injection wells that were installed to re-circulate treated groundwater though the salt plume, desalinization processes, and next steps. figs.

  4. Groundwater System of Sundarbans (Basanti), West Bengal, India

    DEFF Research Database (Denmark)

    Kopmann, Moritz; Binning, Philip John; Bregnhøj, Henrik

    2018-01-01

    In Basanti, a rural block in the Sundarbans, West Bengal, the water availability is vital for its inhabitants. Groundwater levels are decreasing, and a proper understanding of key factors influencing the water resource is required. In the following, a social review of Basanti is given followed...... by a geologic and hydrostratigraphic analysis. The main hydrologic flows, a water balance, and the trend of salinity in the groundwater are presented. Finally, available long- and short-term drawdown data of South 24 Parganas and Basanti to determine groundwater level and annual recharge trends. The assessment...

  5. A conceptual model of the hydrogeologic framework, geochemistry, and groundwater-flow system of the Edwards-Trinity and related aquifers in the Pecos County region, Texas

    Science.gov (United States)

    Bumgarner, Johnathan R.; Stanton, Gregory P.; Teeple, Andrew; Thomas, Jonathan V.; Houston, Natalie A.; Payne, Jason; Musgrove, MaryLynn

    2012-01-01

    A conceptual model of the hydrogeologic framework, geochemistry, and groundwater-flow system of the Edwards-Trinity and related aquifers, which include the Pecos Valley, Igneous, Dockum, Rustler, and Capitan Reef aquifers, was developed as the second phase of a groundwater availability study in the Pecos County region in west Texas. The first phase of the study was to collect and compile groundwater, surface-water, water-quality, geophysical, and geologic data in the area. The third phase of the study involves a numerical groundwater-flow model of the Edwards-Trinity aquifer in order to simulate groundwater conditions based on various groundwater-withdrawal scenarios. Resource managers plan to use the results of the study to establish management strategies for the groundwater system. The hydrogeologic framework is composed of the hydrostratigraphy, structural features, and hydraulic properties of the groundwater system. Well and geophysical logs were interpreted to define the top and base surfaces of the Edwards-Trinity aquifer units. Elevations of the top and base of the Edwards-Trinity aquifer generally decrease from the southwestern part of the study area to the northeast. The thicknesses of the Edwards-Trinity aquifer units were calculated using the interpolated top and base surfaces of the hydrostratigraphic units. Some of the thinnest sections of the aquifer were in the eastern part of the study area and some of the thickest sections were in the Pecos, Monument Draw, and Belding-Coyanosa trough areas. Normal-fault zones, which formed as growth and collapse features as sediments were deposited along the margins of more resistant rocks and as overlying sediments collapsed into the voids created by the dissolution of Permian-age evaporite deposits, were delineated based on the interpretation of hydrostratigraphic cross sections. The lowest aquifer transmissivity values were measured in the eastern part of the study area; the highest transmissivity values were

  6. Ground Water Recharge Estimation Using Water Table Fluctuation Method And By GIS Applications

    Science.gov (United States)

    Vajja, V.; Bekkam, V.; Nune, R.; M. v. S, R.

    2007-05-01

    Quite often it has become a debating point that how much recharge is occurring to the groundwater table through rainfall on one hand and through recharge structures such as percolation ponds and checkdams on the other. In the present investigations Musi basin of Andhra Pradesh, India is selected for study during the period 2005-06. Pre-monsoon and Post-monsoon groundwater levels are collected through out the Musi basin at 89 locations covering an area11, 291.69 km2. Geology of the study area and rainfall data during the study period has been collected. The contour maps of rainfall and the change in groundwater level between Pre-monsoon and Post- monsoon have been prepared. First the change in groundwater storage is estimated for each successive strips of areas enclosed between two contours of groundwater level fluctuations. In this calculation Specific yield (Sy) values are adopted based on the local Geology. Areas between the contours are estimated through Arc GIS software package. All such storages are added to compute the total storage for the entire basin. In order to find out the percent of rainfall converted into groundwater storage as well as to find out the ground water recharge due to storageponds, a contour map of rainfall for the study area is prepared and areas between successive contours have been calculated. Based on the Geology map, Infiltration values are adopted for each successive strip of the contour area. Then the amount of water infiltrated into the ground is calculated by adjusting the infiltration values for each strip, so that the total infiltrated water for the entire basin is matched with change in Ground water storage, which is 1314.37 MCM for the upper Musi basin while it is 2827.29 MCM for entire Musi basin. With this procedure on an average 29.68 and 30.66 percent of Rainfall is converted into Groundwater recharge for Upper Musi and for entire Musi basin respectively. In the total recharge, the contribution of rainfall directly to

  7. Managed Aquifer Recharge in Italy: present and prospects.

    Science.gov (United States)

    Rossetto, Rudy

    2015-04-01

    On October the 3rd 2014, a one-day Workshop on Managed Aquifer Recharge (MAR) experiences in Italy took place at the GEOFLUID fair in Piacenza. It was organized within the framework of the EIP AG 128 - MAR Solutions - Managed Aquifer Recharge Strategies and Actions and the EU FPVII MARSOL. The event aimed at showcasing present experiences on MAR in Italy while at the same time starting a network among all the Institutions involved. In this contribution, we discuss the state of MAR application in Italy and summarize the outcomes of that event. In Italy aquifer recharge is traditionally applied unintentionally, by increasing riverbank filtration or because of excess irrigation. A certain interest for artificial recharge of aquifers arose at the end of the '70s and the beginning of the '80s and tests have been carried out in Tuscany, Veneto and Friuli Venezia Giulia. During the last years some projects on aquifer recharge were co-financed by the European Commission mainly through the LIFE program. Nearly all of them use the terminology of artificial recharge instead of MAR. They are: - TRUST (Tool for regional - scale assessment of groundwater storage improvement in adaptation to climate change, LIFE07 ENV/IT/000475; Marsala 2014); - AQUOR (Implementation of a water saving and artificial recharging participated strategy for the quantitative groundwater layer rebalance of the upper Vicenza's plain - LIFE 2010 ENV/IT/380; Mezzalira et al. 2014); - WARBO (Water re-born - artificial recharge: innovative technologies for the sustainable management of water resources, LIFE10 ENV/IT/000394; 2014). While the TRUST project dealt in general with aquifer recharge, AQUOR and WARBO focused essentially on small scale demonstration plants. Within the EU FPVII-ENV-2013 MARSOL project (Demonstrating Managed Aquifer Recharge as a Solution to Water Scarcity and Drought; 2014), a dedicated monitoring and decision support system is under development to manage recharge at a large scale

  8. Geostatistical analysis of tritium, groundwater age and other noble gas derived parameters in California.

    Science.gov (United States)

    Visser, A; Moran, J E; Hillegonds, Darren; Singleton, M J; Kulongoski, Justin T; Belitz, Kenneth; Esser, B K

    2016-03-15

    Key characteristics of California groundwater systems related to aquifer vulnerability, sustainability, recharge locations and mechanisms, and anthropogenic impact on recharge are revealed in a spatial geostatistical analysis of a unique data set of tritium, noble gases and other isotopic analyses unprecedented in size at nearly 4000 samples. The correlation length of key groundwater residence time parameters varies between tens of kilometers ((3)H; age) to the order of a hundred kilometers ((4)Heter; (14)C; (3)Hetrit). The correlation length of parameters related to climate, topography and atmospheric processes is on the order of several hundred kilometers (recharge temperature; δ(18)O). Young groundwater ages that highlight regional recharge areas are located in the eastern San Joaquin Valley, in the southern Santa Clara Valley Basin, in the upper LA basin and along unlined canals carrying Colorado River water, showing that much of the recent recharge in central and southern California is dominated by river recharge and managed aquifer recharge. Modern groundwater is found in wells with the top open intervals below 60 m depth in the southeastern San Joaquin Valley, Santa Clara Valley and Los Angeles basin, as the result of intensive pumping and/or managed aquifer recharge operations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Determining the impacts of experimental forest plantation on groundwater recharge in the Nebraska Sand Hills (USA) using chloride and sulfate

    Science.gov (United States)

    Adane, Z. A.; Gates, J. B.

    2015-02-01

    Although impacts of land-use changes on groundwater recharge have been widely demonstrated across diverse environmental settings, most previous research has focused on the role of agriculture. This study investigates recharge impacts of tree plantations in a century-old experimental forest surrounded by mixed-grass prairie in the Northern High Plains (Nebraska National Forest), USA. Recharge was estimated using solute mass balance methods from unsaturated zone cores beneath 10 experimental plots with different vegetation and planting densities. Pine and cedar plantation plots had uniformly lower moisture contents and higher solute concentrations than grasslands. Cumulative solute concentrations were greatest beneath the plots with the highest planting densities (chloride concentrations 225-240 % and sulfate concentrations 175-230 % of the grassland plot). Estimated recharge rates beneath the dense plantations (4-10 mm yr-1) represent reductions of 86-94 % relative to the surrounding native grassland. Relationships between sulfate, chloride, and moisture content in the area's relatively homogenous sandy soils confirm that the unsaturated zone solute signals reflect partitioning between drainage and evapotranspiration in this setting. This study is among the first to explore afforestation impacts on recharge beneath sandy soils and sulfate as a tracer of deep drainage.

  10. Proposed artificial recharge studies in northern Qatar

    Science.gov (United States)

    Kimrey, J.O.

    1985-01-01

    The aquifer system in northern Qatar comprises a water-table aquifer in the Rus Formation which is separated by an aquitard from a partially confined aquifer in the top of the overlying Umm er Radhuma Formation. These two aquifers are composed of limestone and dolomite of Eocene and Paleocene age and contain a fragile lens of freshwater which is heavily exploited as a source of water for agricultural irrigation. Net withdrawals are greatly in excess of total recharge, and quality of ground water is declining. Use of desalinated seawater for artificial recharge has been proposed for the area. Artificial recharge, on a large scale, could stabilize the decline in ground-water quality while allowing increased withdrawals for irrigation. The proposal appears technically feasible. Recharge should be by injection to the Umm er Radhuma aquifer whose average transmissivity is about 2,000 meters squared per day (as compared to an average of about 200 meters squared per day for the Rus aquifer). Implementation of artificial recharge should be preceded by a hydrogeologic appraisal. These studies should include test drilling, conventional aquifer tests, and recharge-recovery tests at four sites in northern Qatar. (USGS)

  11. Simulation of the Groundwater-Flow System in Pierce, Polk, and St. Croix Counties, Wisconsin

    Science.gov (United States)

    Juckem, Paul F.

    2009-01-01

    Groundwater is the sole source of residential water supply in Pierce, Polk, and St. Croix Counties, Wisconsin. A regional three-dimensional groundwater-flow model and three associated demonstration inset models were developed to simulate the groundwater-flow systems in the three-county area. The models were developed by the U.S. Geological Survey in cooperation with the three county governments. The objectives of the regional model of Pierce, Polk, and St. Croix Counties were to improve understanding of the groundwaterflow system and to develop a tool suitable for evaluating the effects of potential water-management programs. The regional groundwater-flow model described in this report simulates the major hydrogeologic features of the modeled area, including bedrock and surficial aquifers, groundwater/surface-water interactions, and groundwater withdrawals from high-capacity wells. Results from the regional model indicate that about 82 percent of groundwater in the three counties is from recharge within the counties; 15 percent is from surface-water sources, consisting primarily of recirculated groundwater seepage in areas with abrupt surface-water-level changes, such as near waterfalls, dams, and the downgradient side of reservoirs and lakes; and 4 percent is from inflow across the county boundaries. Groundwater flow out of the counties is to streams (85 percent), outflow across county boundaries (14 percent), and pumping wells (1 percent). These results demonstrate that the primary source of groundwater withdrawn by pumping wells is water that recharges within the counties and would otherwise discharge to local streams and lakes. Under current conditions, the St. Croix and Mississippi Rivers are groundwater discharge locations (gaining reaches) and appear to function as 'fully penetrating' hydraulic boundaries such that groundwater does not cross between Wisconsin and Minnesota beneath them. Being hydraulic boundaries, however, they can change in response to

  12. Policy Preferences about Managed Aquifer Recharge for Securing Sustainable Water Supply to Chennai City, India

    Directory of Open Access Journals (Sweden)

    Norbert Brunner

    2014-12-01

    Full Text Available The objective of this study is to bring out the policy changes with respect to managed aquifer recharge (focusing on infiltration ponds, which in the view of relevant stakeholders may ease the problem of groundwater depletion in the context of Chennai City; Tamil Nadu; India. Groundwater is needed for the drinking water security of Chennai and overexploitation has resulted in depletion and seawater intrusion. Current policies at the municipal; state and national level all support recharge of groundwater and rainwater harvesting to counter groundwater depletion. However, despite such favorable policies, the legal framework and the administrative praxis do not support systematic approaches towards managed aquifer recharge in the periphery of Chennai. The present study confirms this, considering the mandates of governmental key-actors and a survey of the preferences and motives of stakeholder representatives. There are about 25 stakeholder groups with interests in groundwater issues, but they lack a common vision. For example, conflicting interest of stakeholders may hinder implementation of certain types of managed aquifer recharge methods. To overcome this problem, most stakeholders support the idea to establish an authority in the state for licensing groundwater extraction and overseeing managed aquifer recharge.

  13. Investigation of geochemical indicators to evaluate the connection between inland and coastal groundwater systems near Kaloko-Honokōhau National Historical Park, Hawai‘i

    International Nuclear Information System (INIS)

    Tillman, Fred D; Oki, Delwyn S.; Johnson, Adam G.; Barber, Larry B.; Beisner, Kimberly R.

    2014-01-01

    Highlights: • The connection between inland and coastal aquifers near Kona, Hawai‘i is uncertain. • If connected, increased inland groundwater pumping may threaten coastal ecosystems. • Connection of inland and coastal aquifers was investigated using geochemical data. • Stable isotope results provide strong evidence of a connection between the systems. • Other geochemical data suggest a connection but are not conclusive. - Abstract: Kaloko-Honokōhau National Historical Park (KAHO) is a coastal sanctuary on the western side of the Island of Hawai‘i that was established in 1978 to preserve, interpret, and perpetuate traditional Native Hawaiian culture and activities. KAHO contains a variety of culturally and ecologically significant water resources and water-related habitat for species that have been declared as threatened or endangered by the U.S. Fish and Wildlife Service, or are candidate threatened or endangered species. These habitats are dependent on coastal unconfined groundwater in a freshwater-lens system. The coastal unconfined-groundwater system is recharged by local infiltration of rainfall but also may receive recharge from an inland groundwater system containing groundwater impounded to high altitudes. The area inland of and near KAHO is being rapidly urbanized and increased groundwater withdrawals from the inland impounded-groundwater system may affect habitat and water quality in KAHO, depending on the extent of connection between the coastal unconfined groundwater and inland impounded-groundwater. An investigation of the geochemistry of surface-water and groundwater samples in and near KAHO was performed to evaluate the presence or absence of a connection between the inland impounded- and coastal unconfined-groundwater systems in the area. Analyses of major ions, selected trace elements, rare-earth elements, and strontium-isotope ratio results from ocean, fishpond, anchialine pool, and groundwater samples were consistent with a linear

  14. Responses of the sustainable yield of groundwater to annual rainfall and pumping patterns in the Baotou Plain, North China

    Science.gov (United States)

    Liao, Z.; LONG, Y., Sr.; Wei, Y.; Guo, Z.

    2017-12-01

    Serious water deficits and deteriorating environmental quality are threatening the sustainable socio-economic development and the protection of the ecology and the environment in North China, especially in Baotou City. There is a common misconception that groundwater extraction can be sustainable if the pumping rate does not exceed the total natural recharge in a groundwater basin. The truth is that the natural recharge is mainly affected by the rainfall and that groundwater withdrawal determines the sustainable yield of the aquifer flow system. The concept of the sustainable yield is defined as the allowance pumping patterns and rates that avoid adverse impacts on the groundwater system. The sustainable yield introduced in this paper is a useful baseline for groundwater management under all rainfall conditions and given pumping scenarios. A dynamic alternative to the groundwater sustainable yield for a given pumping pattern and rate should consider the responses of the recharge, discharge, and evapotranspiration to the groundwater level fluctuation and to different natural rainfall conditions. In this study, methods for determining the sustainable yield through time series data of groundwater recharge, discharge, extraction, and precipitation in an aquifer are introduced. A numerical simulation tool was used to assess and quantify the dynamic changes in groundwater recharge and discharge under excessive pumping patterns and rates and to estimate the sustainable yield of groundwater flow based on natural rainfall conditions and specific groundwater development scenarios during the period of 2007 to 2014. The results of this study indicate that the multi-year sustainable yield only accounts for about one-half of the average annual recharge. The future sustainable yield for the current pumping scenarios affected by rainfall conditions are evaluated quantitatively to obtain long-term groundwater development strategies. The simulation results show that sufficient

  15. On-Farm, Almond Orchard Flooding as a Viable Aquifer Recharge Alternative

    Science.gov (United States)

    Ulrich, C.; Nico, P. S.; Wu, Y.; Newman, G. A.; Conrad, M. E.; Dahlke, H. E.

    2017-12-01

    In 2014, California legislators passed the Sustainable Groundwater Management Act (SGMA), which requires groundwater sustainability agencies (areas) to identify/prioritize water basins, develop current and projected water use/needs, develop a groundwater management plan, develop fees, etc. One of the challenges for implementing SGMA is the lack of data that can support alternative groundwater recharge methods such as on-farm flooding. Prior to anthropogenic river control, river floodplains captured excess water during overbank flow in the rainy season in the CA central valley. Today levees and canals strategically route rainy season high flows to the delta/ocean when irrigation water is not needed. Utilizing farmland once again as infiltration basins for groundwater banking and aquifer recharge could be a viable answer to California's depleted central valley aquifers. Prior to 2017, U.C. Davis had partnered with the Almond Board of California (ABC) and local growers to study the efficacy of agricultural flooding and the effects on annual almond crops (. LBNL joined this team to help understand the conveyance of recharge water, using electrical resistivity tomography (ERT), into the subsurface (i.e. localized fast paths, depth of infiltration, etc.) during flooding events. The fate of the recharge water is what is significant to understanding the viability of on-farm flooding as an aquifer recharge option. In this study two orchards (in Delhi and Modesto, CA), each approximately 2 acres, were flooded during the almond tree dormant period (January), to recharge 2 acre/ft of water into the local aquifers. ERT was used to characterize (soil structure) and monitor water infiltration over a single flooding event to investigate the fate of applied water. Data were collected every hour prior to flooding (baseline), during, and after all flood water had infiltrated (about 5 days total). Our time-lapse ERT results show a heterogeneous soil structure that leads to non

  16. Karst Aquifer Recharge: A Case History of over Simplification from the Uley South Basin, South Australia

    Directory of Open Access Journals (Sweden)

    Nara Somaratne

    2015-02-01

    Full Text Available The article “Karst aquifer recharge: Comments on ‘Characteristics of Point Recharge in Karst Aquifers’, by Adrian D. Werner, 2014, Water 6, doi:10.3390/w6123727” provides misrepresentation in some parts of Somaratne [1]. The description of Uley South Quaternary Limestone (QL as unconsolidated or poorly consolidated aeolianite sediments with the presence of well-mixed groundwater in Uley South [2] appears unsubstantiated. Examination of 98 lithological descriptions with corresponding drillers’ logs show only two wells containing bands of unconsolidated sediments. In Uley South basin, about 70% of salinity profiles obtained by electrical conductivity (EC logging from monitoring wells show stratification. The central and north central areas of the basin receive leakage from the Tertiary Sand (TS aquifer thereby influencing QL groundwater characteristics, such as chemistry, age and isotope composition. The presence of conduit pathways is evident in salinity profiles taken away from TS water affected areas. Pumping tests derived aquifer parameters show strong heterogeneity, a typical characteristic of karst aquifers. Uley South QL aquifer recharge is derived from three sources; diffuse recharge, point recharge from sinkholes and continuous leakage of TS water. This limits application of recharge estimation methods, such as the conventional chloride mass balance (CMB as the basic premise of the CMB is violated. The conventional CMB is not suitable for accounting chloride mass balance in groundwater systems displaying extreme range of chloride concentrations and complex mixing [3]. Over simplification of karst aquifer systems to suit application of the conventional CMB or 1-D unsaturated modelling as described in Werner [2], is not suitable use of these recharge estimation methods.

  17. Characterizing the Sensitivity of Groundwater Storage to Climate variation in the Indus Basin

    Science.gov (United States)

    Huang, L.; Sabo, J. L.

    2017-12-01

    Indus Basin represents an extensive groundwater aquifer facing the challenge of effective management of limited water resources. Groundwater storage is one of the most important variables of water balance, yet its sensitivity to climate change has rarely been explored. To better estimate present and future groundwater storage and its sensitivity to climate change in the Indus Basin, we analyzed groundwater recharge/discharge and their historical evolution in this basin. Several methods are applied to specify the aquifer system including: water level change and storativity estimates, gravity estimates (GRACE), flow model (MODFLOW), water budget analysis and extrapolation. In addition, all of the socioeconomic and engineering aspects are represented in the hydrological system through the change of temporal and spatial distributions of recharge and discharge (e.g., land use, crop structure, water allocation, etc.). Our results demonstrate that the direct impacts of climate change will result in unevenly distributed but increasing groundwater storage in the short term through groundwater recharge. In contrast, long term groundwater storage will decrease as a result of combined indirect and direct impacts of climate change (e.g. recharge/discharge and human activities). The sensitivity of groundwater storage to climate variation is characterized by topography, aquifer specifics and land use. Furthermore, by comparing possible outcomes of different human interventions scenarios, our study reveals human activities play an important role in affecting the sensitivity of groundwater storage to climate variation. Over all, this study presents the feasibility and value of using integrated hydrological methods to support sustainable water resource management under climate change.

  18. Model Refinement and Simulation of Groundwater Flow in Clinton, Eaton, and Ingham Counties, Michigan

    Science.gov (United States)

    Luukkonen, Carol L.

    2010-01-01

    A groundwater-flow model that was constructed in 1996 of the Saginaw aquifer was refined to better represent the regional hydrologic system in the Tri-County region, which consists of Clinton, Eaton, and Ingham Counties, Michigan. With increasing demand for groundwater, the need to manage withdrawals from the Saginaw aquifer has become more important, and the 1996 model could not adequately address issues of water quality and quantity. An updated model was needed to better address potential effects of drought, locally high water demands, reduction of recharge by impervious surfaces, and issues affecting water quality, such as contaminant sources, on water resources and the selection of pumping rates and locations. The refinement of the groundwater-flow model allows simulations to address these issues of water quantity and quality and provides communities with a tool that will enable them to better plan for expansion and protection of their groundwater-supply systems. Model refinement included representation of the system under steady-state and transient conditions, adjustments to the estimated regional groundwater-recharge rates to account for both temporal and spatial differences, adjustments to the representation and hydraulic characteristics of the glacial deposits and Saginaw Formation, and updates to groundwater-withdrawal rates to reflect changes from the early 1900s to 2005. Simulations included steady-state conditions (in which stresses remained constant and changes in storage were not included) and transient conditions (in which stresses changed in annual and monthly time scales and changes in storage within the system were included). These simulations included investigation of the potential effects of reduced recharge due to impervious areas or to low-rainfall/drought conditions, delineation of contributing areas with recent pumping rates, and optimization of pumping subject to various quantity and quality constraints. Simulation results indicate

  19. Generalized hydrogeologic framework and groundwater budget for a groundwater availability study for the glacial aquifer system of the United States

    Science.gov (United States)

    Reeves, Howard W.; Bayless, E. Randall; Dudley, Robert W.; Feinstein, Daniel T.; Fienen, Michael N.; Hoard, Christopher J.; Hodgkins, Glenn A.; Qi, Sharon L.; Roth, Jason L.; Trost, Jared J.

    2017-12-14

    The glacial aquifer system groundwater availability study seeks to quantify (1) the status of groundwater resources in the glacial aquifer system, (2) how these resources have changed over time, and (3) likely system response to future changes in anthropogenic and environmental conditions. The glacial aquifer system extends from Maine to Alaska, although the focus of this report is the part of the system in the conterminous United States east of the Rocky Mountains. The glacial sand and gravel principal aquifer is the largest source of public and self-supplied industrial supply for any principal aquifer and also is an important source for irrigation supply. Despite its importance for water supply, water levels in the glacial aquifer system are generally stable varying with climate and only locally from pumping. The hydrogeologic framework developed for this study includes the information from waterwell records and classification of material types from surficial geologic maps into likely aquifers dominated by sand and gravel deposits. Generalized groundwater budgets across the study area highlight the variation in recharge and discharge primarily driven by climate.

  20. Recharge Estimation Using Water, Chloride and Isotope Mass Balances

    Science.gov (United States)

    Dogramaci, S.; Firmani, G.; Hedley, P.; Skrzypek, G.; Grierson, P. F.

    2014-12-01

    Discharge of surplus mine water into ephemeral streams may elevate groundwater levels and alter the exchange rate between streams and underlying aquifers but it is unclear whether volumes and recharge processes are within the range of natural variability. Here, we present a case study of an ephemeral creek in the semi-arid subtropical Hamersley Basin that has received continuous mine discharge for more than five years. We used a numerical model coupled with repeated measurements of water levels, chloride concentrations and the hydrogen and oxygen stable isotope composition (δ2H and δ18O) to estimate longitudinal evapotranspiration and recharge rates along a 27 km length of Weeli Wolli Creek. We found that chloride increased from 74 to 120 mg/L across this length, while δ18O increased from -8.24‰ to -7.00‰. Groundwater is directly connected to the creek for the first 13 km and recharge rates are negligible. Below this point, the creek flows over a highly permeable aquifer and water loss by recharge increases to a maximum rate of 4.4 mm/d, which accounts for ~ 65% of the total water discharged to the creek. Evapotranspiration losses account for the remaining ~35%. The calculated recharge from continuous flow due to surplus water discharge is similar to that measured for rainfall-driven flood events along the creek. Groundwater under the disconnected section of the creek is characterised by a much lower Cl concentration and more depleted δ18O value than mining discharge water but is similar to flood water generated by large episodic rainfall events. Our results suggest that the impact of recharge from continuous flow on the creek has not extended beyond 27 km from the discharge point. Our approach using a combination of hydrochemical and isotope methods coupled with classical surface flow hydraulic modelling allowed evaluation of components of water budget otherwise not possible in a highly dynamic system that is mainly driven by infrequent but large episodic

  1. Groundwater vulnerability mapping in Guadalajara aquifers system (Western Mexico)

    Science.gov (United States)

    Rizo-Decelis, L. David; Marín, Ana I.; Andreo, Bartolomé

    2016-04-01

    Groundwater vulnerability mapping is a practical tool to implement strategies for land-use planning and sustainable socioeconomic development coherent with groundwater protection. The objective of vulnerability mapping is to identify the most vulnerable zones of catchment areas and to provide criteria for protecting the groundwater used for drinking water supply. The delineation of protection zones in fractured aquifers is a challenging task due to the heterogeneity and anisotropy of hydraulic conductivities, which makes difficult prediction of groundwater flow organization and flow velocities. Different methods of intrinsic groundwater vulnerability mapping were applied in the Atemajac-Toluquilla groundwater body, an aquifers system that covers around 1300 km2. The aquifer supplies the 30% of urban water resources of the metropolitan area of Guadalajara (Mexico), where over 4.6 million people reside. Study area is located in a complex neotectonic active volcanic region in the Santiago River Basin (Western Mexico), which influences the aquifer system underneath the city. Previous works have defined the flow dynamics and identified the origin of recharge. In addition, the mixture of fresh groundwater with hydrothermal and polluted waters have been estimated. Two main aquifers compose the multilayer system. The upper aquifer is unconfined and consists of sediments and pyroclastic materials. Recharge of this aquifer comes from rainwater and ascending vertical fluids from the lower aquifer. The lower aquifer consists of fractured basalts of Pliocene age. Formerly, the main water source has been the upper unit, which is a porous and unconsolidated unit, which acts as a semi-isotropic aquifer. Intense groundwater usage has resulted in lowering the water table in the upper aquifer. Therefore, the current groundwater extraction is carried out from the deeper aquifer and underlying bedrock units, where fracture flow predominates. Pollution indicators have been reported in

  2. Uncertainty in recharge estimation: impact on groundwater vulnerability assessments for the Pearl Harbor Basin, O'ahu, Hawai'i, U.S.A.

    Science.gov (United States)

    Giambelluca, Thomas W.; Loague, Keith; Green, Richard E.; Nullet, Michael A.

    1996-06-01

    In this paper, uncertainty in recharge estimates is investigated relative to its impact on assessments of groundwater contamination vulnerability using a relatively simple pesticide mobility index, attenuation factor (AF). We employ a combination of first-order uncertainty analysis (FOUA) and sensitivity analysis to investigate recharge uncertainties for agricultural land on the island of O'ahu, Hawai'i, that is currently, or has been in the past, under sugarcane or pineapple cultivation. Uncertainty in recharge due to recharge component uncertainties is 49% of the mean for sugarcane and 58% of the mean for pineapple. The components contributing the largest amounts of uncertainty to the recharge estimate are irrigation in the case of sugarcane and precipitation in the case of pineapple. For a suite of pesticides formerly or currently used in the region, the contribution to AF uncertainty of recharge uncertainty was compared with the contributions of other AF components: retardation factor (RF), a measure of the effects of sorption; soil-water content at field capacity (ΘFC); and pesticide half-life (t1/2). Depending upon the pesticide, the contribution of recharge to uncertainty ranks second or third among the four AF components tested. The natural temporal variability of recharge is another source of uncertainty in AF, because the index is calculated using the time-averaged recharge rate. Relative to the mean, recharge variability is 10%, 44%, and 176% for the annual, monthly, and daily time scales, respectively, under sugarcane, and 31%, 112%, and 344%, respectively, under pineapple. In general, uncertainty in AF associated with temporal variability in recharge at all time scales exceeds AF. For chemicals such as atrazine or diuron under sugarcane, and atrazine or bromacil under pineapple, the range of AF uncertainty due to temporal variability in recharge encompasses significantly higher levels of leaching potential at some locations than that indicated by the

  3. Use of environmental isotope tracer and GIS techniques to estimate basin recharge

    Science.gov (United States)

    Odunmbaku, Abdulganiu A. A.

    The extensive use of ground water only began with the advances in pumping technology at the early portion of 20th Century. Groundwater provides the majority of fresh water supply for municipal, agricultural and industrial uses, primarily because of little to no treatment it requires. Estimating the volume of groundwater available in a basin is a daunting task, and no accurate measurements can be made. Usually water budgets and simulation models are primarily used to estimate the volume of water in a basin. Precipitation, land surface cover and subsurface geology are factors that affect recharge; these factors affect percolation which invariably affects groundwater recharge. Depending on precipitation, soil chemistry, groundwater chemical composition, gradient and depth, the age and rate of recharge can be estimated. This present research proposes to estimate the recharge in Mimbres, Tularosa and Diablo Basin using the chloride environmental isotope; chloride mass-balance approach and GIS. It also proposes to determine the effect of elevation on recharge rate. Mimbres and Tularosa Basin are located in southern New Mexico State, and extend southward into Mexico. Diablo Basin is located in Texas in extends southward. This research utilizes the chloride mass balance approach to estimate the recharge rate through collection of groundwater data from wells, and precipitation. The data were analysed statistically to eliminate duplication, outliers, and incomplete data. Cluster analysis, piper diagram and statistical significance were performed on the parameters of the groundwater; the infiltration rate was determined using chloride mass balance technique. The data was then analysed spatially using ArcGIS10. Regions of active recharge were identified in Mimbres and Diablo Basin, but this could not be clearly identified in Tularosa Basin. CMB recharge for Tularosa Basin yields 0.04037mm/yr (0.0016in/yr), Diablo Basin was 0.047mm/yr (0.0016 in/yr), and 0.2153mm/yr (0.00848in

  4. Benefits and Economic Costs of Managed Aquifer Recharge in California

    Directory of Open Access Journals (Sweden)

    Debra Perrone

    2016-07-01

    Full Text Available doi: http://dx.doi.org/10.15447/sfews.2016v14iss2art4Groundwater management is important and challenging, and nowhere is this more evident than in California. Managed aquifer recharge (MAR projects can play an important role in ensuring California manages its groundwater sustainably. Although the benefits and economic costs of surface water storage have been researched extensively, the benefits and economic costs of MAR have been little researched. Historical groundwater data are sparse or proprietary within the state, often impairing groundwater analyses. General obligation bonds from ballot propositions offer a strategic means of mining information about MAR projects, because the information is available publicly. We used bond-funding applications to identify anticipated MAR project benefits and proposed economic costs. We then compared these costs with actual project costs collected from a survey, and identified factors that promote or limit MAR. Our analysis indicates that the median proposed economic cost for MAR projects in California is $410 per acre-foot per year ($0.33 per cubic meter per year. Increasing Water Supply, Conjunctive Use, and Flood Protection are the most common benefits reported. Additionally, the survey indicates that (1 there are many reported reasons for differences between proposed and actual costs ($US 2015 and (2 there is one primary reason for differences between proposed recharge volumes and actual recharge volumes (AFY: availability of source water for recharge. Although there are differences between proposed and actual costs per recharge volume ($US 2015/AFY, the ranges for proposed costs per recharge volume and actual costs per recharge volume for the projects surveyed generally agree. The two most important contributions to the success of a MAR project are financial support and good communication with stakeholders.

  5. Groundwater Pumping and Streamflow in the Yuba Basin, Sacramento Valley, California

    Science.gov (United States)

    Moss, D. R.; Fogg, G. E.; Wallender, W. W.

    2011-12-01

    Water transfers during drought in California's Sacramento Valley can lead to increased groundwater pumping, and as yet unknown effects on stream baseflow. Two existing groundwater models of the greater Sacramento Valley together with localized, monitoring of groundwater level fluctuations adjacent to the Bear, Feather, and Yuba Rivers, indicate cause and effect relations between the pumping and streamflow. The models are the Central Valley Hydrologic Model (CVHM) developed by the U.S. Geological Survey and C2VSIM developed by Department of Water Resources. Using two models which have similar complexity and data but differing approaches to the agricultural water boundary condition illuminates both the water budget and its uncertainty. Water budget and flux data for localized areas can be obtained from the models allowing for parameters such as precipitation, irrigation recharge, and streamflow to be compared to pumping on different temporal scales. Continuous groundwater level measurements at nested, near-stream piezometers show seasonal variations in streamflow and groundwater levels as well as the timing and magnitude of recharge and pumping. Preliminary results indicate that during years with relatively wet conditions 65 - 70% of the surface recharge for the groundwater system comes from irrigation and precipitation and 30 - 35% comes from streamflow losses. The models further indicate that during years with relatively dry conditions, 55 - 60% of the surface recharge for the groundwater system comes from irrigation and precipitation while 40 - 45% comes from streamflow losses. The models irrigation water demand, surface-water and groundwater supply, and deep percolation are integrated producing values for irrigation pumping. Groundwater extractions during the growing season, approximately between April and October, increase by almost 200%. The effects of increased pumping seasonally are not readily evident in stream stage measurements. However, during dry time

  6. Groundwater age determination using 85Kr and multiple age tracers (SF6, CFCs, and 3H to elucidate regional groundwater flow systems

    Directory of Open Access Journals (Sweden)

    Makoto Kagabu

    2017-08-01

    New hydrological insights for the region: The groundwater ages could not be estimated using CFCs or SF6, particularly in the urban areas because of artificial additions to the concentration over almost the entire study area. However, even in these regional circumstances, apparent ages of approximately 16, 36, and not less than 55 years were obtained for three locations on the A–A’ line (recharge area, discharge area, and stagnant zone of groundwater, respectively from 85Kr measurements. This trend was also supported by lumped parameter model analysis using a time series of 3H observations. In contrast, along the B–B’ line, the groundwater age of not less than 55 years at three locations, including the recharge to discharge area, where CFCs and SF6 were not detected, implies old groundwater: this is also the area in which denitrification occurs. In the C area, very young groundwater was obtained from shallow water and older groundwater was detected at greater depths, as supported by the long-term fluctuations of the NO3−–N concentration in the groundwater. The results of this study can be effectively used as a “time axis” for sustainable groundwater use and protection of groundwater quality in the study area, where groundwater accounts for almost 100% of the drinking water resources.

  7. Groundwater geochemistry of nile delta-desert interface 1.isotope hydrology

    International Nuclear Information System (INIS)

    Hussein, M.F.; Nada, A.A.; Awad, M.A.

    1995-01-01

    Sustenance and environmental protection of groundwater supply is of major concern in the integral environmental development in the arid to sub-arid regions in the Nile basin. Isotope data ( 18O , 2H and 3H ) of groundwater in the west of the Nile delta indicates the contribution of palaeo groundwater component (in the range 0.1 - 0.8 with means of 0.39 and 0.52 for tahrir and khatatbah, respectively) along with sub recent recharge from the delta aquifer and recent recharge from irrigation conveyance canals in desert. Isotope mixing model (developed as Two-input table using excel TM spreads heat on apple Macintosh TM) is proposed to explain the apparent discrepancies in groundwater isotopic composition of khatatbah and tahrir areas assuming the contribution of two isotopically different palaeo-oples with two isotopically similar maind delta groundwater poles. About 0.30% 1 8 O depletion per 10 Km downstream is detected and low northward groundwater recharge is suggested along 75 Km of the western strip of rosetta Nile. Higher sub-recent recharge from the main delta aquifer is believed to take place in khatatbah than tahrir whereas the last is believed to be replenished at present from the irrigation/ drainage network and irrigated fields with higher pollution risk for groundwater system in tahrir aquifer is exposed to northern marine intrusion. Lowering of the piezo metric level is to be expected in the newly exploited desertic areas under over pumping. 9 figs

  8. Regional differences in climate change impacts on groundwater and stream discharge in Denmark

    DEFF Research Database (Denmark)

    Van Roosmalen, Lieke Petronella G; Christensen, Britt S.B.; Sonnenborg, Torben O.

    2007-01-01

    of the hydrological response to the simulated climate change is highly dependant on the geological setting of the model area. In the Jylland area, characterized by sandy top soils and large interconnected aquifers, groundwater recharge increases significantly, resulting in higher groundwater levels and increasing......Regional impact studies of the effects of future climate change are necessary because projected changes in meteorological variables vary regionally and different hydrological systems can react in various ways to the same changes. In this study the effects of climate change on groundwater recharge...... simulates changes in groundwater head, recharge, and discharge. Precipitation, temperature, and reference evapotranspiration increase for both the A2 and B2 scenarios. This results in a significant increase in mean annual net precipitation, but with decreased values in the summer months. The magnitude...

  9. Effects of recharge and discharge on delta2H and delta18O composition and chloride concentration of high arsenic/fluoride groundwater from the Datong Basin, northern China.

    Science.gov (United States)

    Xie, Xianjun; Wang, Yanxin; Su, Chunli; Duan, Mengyu

    2013-02-01

    To better understand the effects of recharge and discharge on the hydrogeochemistry of high levels of arsenic (As) and fluoride (F) in groundwater, environmental isotopic composition (delta2H and delta18O) and chloride (Cl) concentrations were analyzed in 29 groundwater samples collected from the Datong Basin. High arsenic groundwater samples (As > 50 micog/L) were found to be enriched in lighter isotopic composition that ranged from -92 to -78 per thousand for deuterium (delta2H) and from -12.5 to -9.9 per thousand for oxygen-18 (delta18O). High F-containing groundwater (F > 1 mg/L) was relatively enriched in heavier isotopic composition and varied from -90 to -57 per thousand and from -12.2 to -6.7 per thousand for delta2H and delta18O, respectively. High chloride concentrations and delta18O values were primarily measured in groundwater samples from the northern and southwestern portions of the study area, indicating the effect of evaporation on groundwater. The observation of relatively homogenized and low delta18O values and chloride concentrations in groundwater samples from central part of the Datong Basin might be a result of fast recharge by irrigation returns, which suggests that irrigation using arsenic-contaminated groundwater affected the occurrence of high arsenic-containing groundwater in the basin.

  10. Response of the groundwater system in the Guanzhong Basin (central China) to climate change and human activities

    Science.gov (United States)

    Wang, Wenke; Zhang, Zaiyong; Duan, Lei; Wang, Zhoufeng; Zhao, Yaqian; Zhang, Qian; Dai, Meiling; Liu, Huizhong; Zheng, Xiaoyan; Sun, Yibo

    2018-03-01

    The Guanzhong Basin in central China features a booming economy and has suffered severe drought, resulting in serious groundwater depletion in the last 30 years. As a major water resource, groundwater plays a significant role in water supply. The combined impact of climate change and intensive human activities has caused a substantial decline in groundwater recharge and groundwater levels, as well as degradation of groundwater quality and associated changes in the ecosystems. Based on observational data, an integrated approach was used to assess the impact of climate change and human activities on the groundwater system and the base flow of the river basin. Methods included: river runoff records and a multivariate statistical analysis of data including historical groundwater levels and climate; hydro-chemical investigation and trend analysis of the historical hydro-chemical data; wavelet analysis of climate data; and the base flow index. The analyses indicate a clear warming trend and a decreasing trend in rainfall since the 1960s, in addition to increased human activities since the 1970s. The reduction of groundwater recharge in the past 30 years has led to a continuous depletion of groundwater levels, complex changes of the hydro-chemical environment, localized salinization, and a strong decline of the base flow to the river. It is expected that the results will contribute to a more comprehensive management plan for groundwater and the related eco-environment in the face of growing pressures from intensive human activities superimposed on climate change in this region.

  11. Construction and calibration of a groundwater-flow model to assess groundwater availability in the uppermost principal aquifer systems of the Williston Basin, United States and Canada

    Science.gov (United States)

    Davis, Kyle W.; Long, Andrew J.

    2018-05-31

    The U.S. Geological Survey developed a groundwater-flow model for the uppermost principal aquifer systems in the Williston Basin in parts of Montana, North Dakota, and South Dakota in the United States and parts of Manitoba and Saskatchewan in Canada as part of a detailed assessment of the groundwater availability in the area. The assessment was done because of the potential for increased demands and stresses on groundwater associated with large-scale energy development in the area. As part of this assessment, a three-dimensional groundwater-flow model was developed as a tool that can be used to simulate how the groundwater-flow system responds to changes in hydrologic stresses at a regional scale.The three-dimensional groundwater-flow model was developed using the U.S. Geological Survey’s numerical finite-difference groundwater model with the Newton-Rhapson solver, MODFLOW–NWT, to represent the glacial, lower Tertiary, and Upper Cretaceous aquifer systems for steady-state (mean) hydrological conditions for 1981‒2005 and for transient (temporally varying) conditions using a combination of a steady-state period for pre-1960 and transient periods for 1961‒2005. The numerical model framework was constructed based on existing and interpreted hydrogeologic and geospatial data and consisted of eight layers. Two layers were used to represent the glacial aquifer system in the model; layer 1 represented the upper one-half and layer 2 represented the lower one-half of the glacial aquifer system. Three layers were used to represent the lower Tertiary aquifer system in the model; layer 3 represented the upper Fort Union aquifer, layer 4 represented the middle Fort Union hydrogeologic unit, and layer 5 represented the lower Fort Union aquifer. Three layers were used to represent the Upper Cretaceous aquifer system in the model; layer 6 represented the upper Hell Creek hydrogeologic unit, layer 7 represented the lower Hell Creek aquifer, and layer 8 represented the Fox

  12. Quantifying and modelling the contribution of streams that recharge the Querença-Silves aquifer in the south of Portugal

    Directory of Open Access Journals (Sweden)

    N. Salvador

    2012-11-01

    Full Text Available The water balance of the mesocenozoic aquifers of the Algarve, in the south of Portugal has traditionally been estimated considering only direct ("autogenic" recharge from rainfall occurring in the area of the aquifers. Little importance has been attributed to so-called allogenic recharge, originating from streambed infiltration from runoff generated outside the aquifers, particularly in the Palaeozoic rocks to the north where runoff is high. The Querença-Silves (QS aquifer is the most important aquifer of the region both for irrigation and public water supply. Several important and sensitive surface/groundwater ecotones and associated groundwater dependent ecosystems exist at the springs of the natural discharge areas of the aquifer system. A numerical flow model has been in constant development over the last few years and currently is able to reproduce the aquifer's responses to estimated direct recharge and abstraction for the years 2001–2010. However, recharge calculations for the model do not take into account allogenic recharge infiltration along influent reaches of streams. The quantification of allogenic recharge may further improve the assessment of water availability and exploitation risks. In this paper an attempt is made to quantify the average annual contribution of allogenic recharge to the QS aquifer, based on monitoring data of the principal water courses that cross the aquifer system. Significant uncertainties related to surface runoff generated within the aquifer area, as well as areal recharge were identified and the consequences for the optimization of spatial distribution of transmissivity in the groundwater flow model are also addressed.

  13. Groundwater depletion and sustainability of irrigation in the US High Plains and Central Valley

    Science.gov (United States)

    Scanlon, Bridget R.; Faunt, Claudia C.; Longuevergne, Laurent; Reedy, Robert C.; Alley, William M.; McGuire, Virginia L.; McMahon, Peter B.

    2012-01-01

    Aquifer overexploitation could significantly impact crop production in the United States because 60% of irrigation relies on groundwater. Groundwater depletion in the irrigated High Plains and California Central Valley accounts for ∼50% of groundwater depletion in the United States since 1900. A newly developed High Plains recharge map shows that high recharge in the northern High Plains results in sustainable pumpage, whereas lower recharge in the central and southern High Plains has resulted in focused depletion of 330 km3 of fossil groundwater, mostly recharged during the past 13,000 y. Depletion is highly localized with about a third of depletion occurring in 4% of the High Plains land area. Extrapolation of the current depletion rate suggests that 35% of the southern High Plains will be unable to support irrigation within the next 30 y. Reducing irrigation withdrawals could extend the lifespan of the aquifer but would not result in sustainable management of this fossil groundwater. The Central Valley is a more dynamic, engineered system, with north/south diversions of surface water since the 1950s contributing to ∼7× higher recharge. However, these diversions are regulated because of impacts on endangered species. A newly developed Central Valley Hydrologic Model shows that groundwater depletion since the 1960s, totaling 80 km3, occurs mostly in the south (Tulare Basin) and primarily during droughts. Increasing water storage through artificial recharge of excess surface water in aquifers by up to 3 km3 shows promise for coping with droughts and improving sustainability of groundwater resources in the Central Valley. PMID:22645352

  14. Removal of organic micropollutants in an artificial recharge system

    Science.gov (United States)

    Valhondo, C.; Nödler, K.; Köck-Schulmeyer, M.; Hernandez, M.; Licha, T.; Ayora, C.; Carrera, J.

    2012-04-01

    Emerging contaminants including pharmaceutically active compounds (PhACs), personal care products (PCPs) and pesticides are increasingly being identified in the environment. Emerging pollutants and their transformation products show low concentration in the environment (ng/L), but the effects of the mixtures and lifelong exposure to humans are currently unknown. Many of these contaminants are removed under aerobic conditions in water treatment plants. However, several pharmaceuticals and metabolites present in wastewater are not eliminated by conventional treatment processes. Several lab studies, however, show that the behaviour of many of these micropollutants is affected by the dominant redox conditions. However, data from field experiments are limited and sometimes contradictory. Artificial recharge is a widespread technology to increase the groundwater resources. In this study we propose a design to enhance the natural remediation potential of the aquifer with the installation of a reactive layer at the bottom of the infiltration pond. This layer is a mixture of compost, aquifer material, clay and iron oxide. This layer is intended to provide an extra amount of DOC to the recharge water and to promote biodegradation by means of the development of different redox zones along the travel path through the unsaturated zone and within the aquifer. Moreover, compost, clay and iron oxide of the layer are assumed to increase sorption surfaces for neutral, cationic and anionic compounds, respectively. The infiltration system is sited in Sant Vicenç dels Horts (Barcelona, Spain). It consists of a decantation pond, receiving raw water from the Llobregat River (highly affected from treatment plant effluents), and an infiltration pond (5600 m2). The infiltration rate is around 1 m3/m2/day. The system is equipped with a network of piezometers, suction cups and tensiometers. Infiltration periods have been performed before and after the installation of the reactive layer

  15. A multi-tracer approach to delineate groundwater dynamics in the Rio Actopan Basin, Veracruz State, Mexico

    Science.gov (United States)

    Pérez Quezadas, Juan; Heilweil, Victor M.; Cortés Silva, Alejandra; Araguas, Luis; Salas Ortega, María del Rocío

    2016-12-01

    Geochemistry and environmental tracers were used to understand groundwater resources, recharge processes, and potential sources of contamination in the Rio Actopan Basin, Veracruz State, Mexico. Total dissolved solids are lower in wells and springs located in the basin uplands compared with those closer to the coast, likely associated with rock/water interaction. Geochemical results also indicate some saltwater intrusion near the coast and increased nitrate near urban centers. Stable isotopes show that precipitation is the source of recharge to the groundwater system. Interestingly, some high-elevation springs are more isotopically enriched than average annual precipitation at higher elevations, indicating preferential recharge during the drier but cooler winter months when evapotranspiration is reduced. In contrast, groundwater below 1,200 m elevation is more isotopically depleted than average precipitation, indicating recharge occurring at much higher elevation than the sampling site. Relatively cool recharge temperatures, derived from noble gas measurements at four sites (11-20 °C), also suggest higher elevation recharge. Environmental tracers indicate that groundwater residence time in the basin ranges from 12,000 years to modern. While this large range shows varying groundwater flowpaths and travel times, ages using different tracer methods (14C, 3H/3He, CFCs) were generally consistent. Comparing multiple tracers such as CFC-12 with CFC-113 indicates piston-flow to some discharge points, yet binary mixing of young and older groundwater at other points. In summary, groundwater within the Rio Actopan Basin watershed is relatively young (Holocene) and the majority of recharge occurs in the basin uplands and moves towards the coast.

  16. Improving AVSWAT Stream Flow Simulation by Incorporating Groundwater Recharge Prediction in the Upstream Lesti Watershed, East Java, Indonesia

    Directory of Open Access Journals (Sweden)

    Christina Rahayuningtyas

    2014-01-01

    Full Text Available The upstream Lesti watershed is one of the major watersheds of East Java in Indonesia, covering about 38093 hectares. Although there are enough water resources to meet current demands in the basin, many challenges including high spatial and temporal variability in precipitation from year to year exist. It is essential to understand how the climatic condition affects Lesti River stream flow in each sub basin. This study investigated the applicability of using the Soil and Water Assessment Tool (SWAT with the incorporation of groundwater recharge prediction in stream flow simulation in the upstream Lesti watershed. Four observation wells in the upstream Lesti watershed were used to evaluate the seasonal and annual variations in the water level and estimate the groundwater recharge in the deep aquifer. The results show that annual water level rise was within the 2800 - 5700 mm range in 2007, 3900 - 4700 mm in 2008, 3200 - 5100 mm in 2009, and 2800 - 4600 mm in 2010. Based on the specific yield and the measured water level rise, the area-weighted groundwater predictions at the watershed outlet are 736, 820.9, 786.7, 306.4 mm in 2007, 2008, 2009, and 2010, respectively. The consistency test reveals that the R-square statistical value is greater than 0.7, and the DV (% ranged from 32 - 55.3% in 2007 - 2010. Overall, the SWAT model performs better in the wet season flow simulation than the dry season. It is suggested that the SWAT model needs to be improved for stream flow simulation in tropical regions.

  17. Feasibility and potential effects of the proposed Amargosa Creek Recharge Project, Palmdale, California

    Science.gov (United States)

    Christensen, Allen H.; Siade, Adam J.; Martin, Peter; Langenheim, V.E.; Catchings, Rufus D.; Burgess, Matthew K.

    2015-09-17

    Historically, the city of Palmdale and vicinity have relied on groundwater as the primary source of water, owing, in large part, to the scarcity of surface water in the region. Despite recent importing of surface water, groundwater withdrawal for municipal, industrial, and agricultural use has resulted in groundwater-level declines near the city of Palmdale in excess of 200 feet since the early 1900s. To meet the growing water demand in the area, the city of Palmdale has proposed the Amargosa Creek Recharge Project (ACRP), which has a footprint of about 150 acres along the Amargosa Creek 2 miles west of Palmdale, California. The objective of this study was to evaluate the long-term feasibility of recharging the Antelope Valley aquifer system by using infiltration of imported surface water from the California State Water Project in percolation basins at the ACRP.

  18. Groundwater and surface water interaction in a basin surrounded by steep mountains, central Japan

    Science.gov (United States)

    Ikeda, Koichi; Tsujimura, Maki; Kaeriyama, Toshiaki; Nakano, Takanori

    2015-04-01

    Mountainous headwaters and lower stream alluvial plains are important as water recharge and discharge areas from the view point of groundwater flow system. Especially, groundwater and surface water interaction is one of the most important processes to understand the total groundwater flow system from the mountain to the alluvial plain. We performed tracer approach and hydrometric investigations in a basin with an area 948 square km surrounded by steep mountains with an altitude from 250m to 2060m, collected 258 groundwater samples and 112 surface water samples along four streams flowing in the basin. Also, Stable isotopes ratios of oxygen-18 (18O) and deuterium (D) and strontium (Sr) were determined on all water samples. The 18O and D show distinctive values for each sub-basin affected by different average recharge altitudes among four sub-basins. Also, Sr isotope ratio shows the same trend as 18O and D affected by different geological covers in the recharge areas among four sub-basins. The 18O, D and Sr isotope values of groundwater along some rivers in the middle stream region of the basin show close values as the rivers, and suggesting that direct recharge from the river to the shallow groundwater is predominant in that region. Also, a decreasing trend of discharge rate of the stream along the flow supports this idea of the groundwater and surface water interaction in the basin.

  19. Geochemical Triggers of Arsenic Mobilization during Managed Aquifer Recharge.

    Science.gov (United States)

    Fakhreddine, Sarah; Dittmar, Jessica; Phipps, Don; Dadakis, Jason; Fendorf, Scott

    2015-07-07

    Mobilization of arsenic and other trace metal contaminants during managed aquifer recharge (MAR) poses a challenge to maintaining local groundwater quality and to ensuring the viability of aquifer storage and recovery techniques. Arsenic release from sediments into solution has occurred during purified recycled water recharge of shallow aquifers within Orange County, CA. Accordingly, we examine the geochemical processes controlling As desorption and mobilization from shallow, aerated sediments underlying MAR infiltration basins. Further, we conducted a series of batch and column experiments to evaluate recharge water chemistries that minimize the propensity of As desorption from the aquifer sediments. Within the shallow Orange County Groundwater Basin sediments, the divalent cations Ca(2+) and Mg(2+) are critical for limiting arsenic desorption; they promote As (as arsenate) adsorption to the phyllosilicate clay minerals of the aquifer. While native groundwater contains adequate concentrations of dissolved Ca(2+) and Mg(2+), these cations are not present at sufficient concentrations during recharge of highly purified recycled water. Subsequently, the absence of dissolved Ca(2+) and Mg(2+) displaces As from the sediments into solution. Increasing the dosages of common water treatment amendments including quicklime (Ca(OH)2) and dolomitic lime (CaO·MgO) provides recharge water with higher concentrations of Ca(2+) and Mg(2+) ions and subsequently decreases the release of As during infiltration.

  20. Groundwater model of the Great Basin carbonate and alluvial aquifer system version 3.0: Incorporating revisions in southwestern Utah and east central Nevada

    Science.gov (United States)

    Brooks, Lynette E.

    2017-12-01

    The groundwater model described in this report is a new version of previously published steady-state numerical groundwater flow models of the Great Basin carbonate and alluvial aquifer system, and was developed in conjunction with U.S. Geological Survey studies in Parowan, Pine, and Wah Wah Valleys, Utah. This version of the model is GBCAAS v. 3.0 and supersedes previous versions. The objectives of the model for Parowan Valley were to simulate revised conceptual estimates of recharge and discharge, to estimate simulated aquifer storage properties and the amount of reduction in storage as a result of historical groundwater withdrawals, and to assess reduction in groundwater withdrawals necessary to mitigate groundwater-level declines in the basin. The objectives of the model for the area near Pine and Wah Wah Valleys were to recalibrate the model using new observations of groundwater levels and evapotranspiration of groundwater; to provide new estimates of simulated recharge, hydraulic conductivity, and interbasin flow; and to simulate the effects of proposed groundwater withdrawals on the regional flow system. Meeting these objectives required the addition of 15 transient calibration stress periods and 14 projection stress periods, aquifer storage properties, historical withdrawals in Parowan Valley, and observations of water-level changes in Parowan Valley. Recharge in Parowan Valley and withdrawal from wells in Parowan Valley and two nearby wells in Cedar City Valley vary for each calibration stress period representing conditions from March 1940 to November 2013. Stresses, including recharge, are the same in each stress period as in the steady-state stress period for all areas outside of Parowan Valley. The model was calibrated to transient conditions only in Parowan Valley. Simulated storage properties outside of Parowan Valley were set the same as the Parowan Valley properties and are not considered calibrated. Model observations in GBCAAS v. 3.0 are

  1. Prediction of Groundwater Quality Trends Resulting from Anthropogenic Changes in Southeast Florida.

    Science.gov (United States)

    Yi, Quanghee; Stewart, Mark

    2018-01-01

    The effects of surface water flow system changes caused by constructing water-conservation areas and canals in southeast Florida on groundwater quality under the Atlantic Coastal Ridge was investigated with numerical modeling. Water quality data were used to delineate a zone of groundwater with low total dissolved solids (TDS) within the Biscayne aquifer under the ridge. The delineated zone has the following characteristics. Its location generally coincides with an area where the Biscayne aquifer has high transmissivities, corresponds to a high recharge area of the ridge, and underlies a part of the groundwater mound formed under the ridge prior to completion of the canals. This low TDS groundwater appears to be the result of pre-development conditions rather than seepage from the canals constructed after the 1950s. Numerical simulation results indicate that the time for low TDS groundwater under the ridge to reach equilibrium with high TDS surface water in the water-conservation areas and Everglades National Park are approximately 70 and 60 years, respectively. The high TDS groundwater would be restricted to the water-conservation areas and the park due to its slow eastward movement caused by small hydraulic gradients in Rocky Glades and its mixing with the low TDS groundwater under the high-recharge area of the ridge. The flow or physical boundary conditions such as high recharge rates or low hydraulic conductivity layers may affect how the spatial distribution of groundwater quality in an aquifer will change when a groundwater flow system reaches equilibrium with an associated surface water flow system. © 2017, National Ground Water Association.

  2. Assessing the impact of managed aquifer recharge on seasonal low flows in a semi-arid alluvial river

    Science.gov (United States)

    Ronayne, M. J.; Roudebush, J. A.; Stednick, J. D.

    2016-12-01

    Managed aquifer recharge (MAR) is one strategy that can be used to augment seasonal low flows in alluvial rivers. Successful implementation requires an understanding of spatio-temporal groundwater-surface water exchange. In this study we conducted numerical groundwater modeling to analyze the performance of an existing MAR system in the South Platte River Valley in northeastern Colorado (USA). The engineered system involves a spatial reallocation of water during the winter months; alluvial groundwater is extracted near the river and pumped to upgradient recharge ponds, with the intent of producing a delayed hydraulic response that increases the riparian zone water table (and therefore streamflow) during summer months. Higher flows during the summer are required to improve riverine habitat for threatened species in the Platte River. Modeling scenarios were constrained by surface (streamflow gaging) and subsurface (well data) measurements throughout the study area. We compare two scenarios to analyze the impact of MAR: a natural base case scenario and an active management scenario that includes groundwater pumping and managed recharge. Steady-periodic solutions are used to evaluate the long-term stabilized behavior of the stream-aquifer system with and without pumping/recharge. Streamflow routing is included in the model, which permits quantification of the timing and location of streamflow accretion (increased streamflow associated with MAR). An analysis framework utilizing capture concepts is developed to interpret seasonal changes in head-dependent flows to/from the aquifer, including groundwater-surface water exchange that impacts streamflow. Results demonstrate that accretion occurs during the target low-flow period but is not limited to those months, highlighting an inefficiency that is a function of the aquifer geometry and hydraulic properties. The results of this study offer guidance for other flow augmentation projects that rely on water storage in shallow

  3. Groundwater vulnerability map for South Africa

    African Journals Online (AJOL)

    Chiedza Musekiwa

    decision-making for groundwater management and protection. ... (1) Depth to water table; (2) Recharge (net); (3) Aquifer media; (4) Soil media; ... Methodology .... Petty, R 1987, 'DRASTIC: A standardized system for evaluating ground water.

  4. Addressing the Sustainability of Groundwater Extraction in California Using Hydrochronology

    Science.gov (United States)

    Moran, J. E.; Visser, A.; Singleton, M. J.; Esser, B. K.

    2017-12-01

    In urban and agricultural settings in California, intense pressure on water supplies has led to extensive managed aquifer recharge and extensive overdraft in these areas, respectively. The California Sustainable Groundwater Management Act (SGMA) includes criteria for pumping that maintains groundwater levels and basin storage, and avoids stream depletion and degradation of water quality. Most sustainability plans will likely use water level monitoring and water budget balancing based on integrated flow models as evidence of compliance. However, hydrochronology data are applicable to several of the criteria, and provide an independent method of addressing questions related to basin turnover time, recharge rate, surface water-groundwater interaction, and the age distribution at pumping wells. We have applied hydrochronology (mainly tritium-helium groundwater age dating and extrinsic tracers) in urban areas to delineate flowpaths of artificially recharged water, to identify stagnant zones bypassed by the engineered flow system, and to predict vulnerability of drinking water sources to contamination. In agricultural areas, we have applied multi-tracer hydrochronology to delineate groundwater stratigraphy, to identify paleowater, and to project future nitrate concentrations in long-screened wells. This presentation will describe examples in which groundwater dating and other tracer methods can be applied to directly address the SGMA criteria for sustainable groundwater pumping.

  5. Groundwater reorganization in the Floridan aquifer following Holocene sea-level rise

    OpenAIRE

    Morrissey, SK; Clark, JF; Bennett, M; Richardson, E; Stute, M

    2010-01-01

    Sea-level fluctuations, particularly those associated with glacial-interglacial cycles, can have profound impacts on the flow and circulation of coastal groundwater: the water found at present in many coastal aquifers may have been recharged during the last glacial period, when sea level was over 100 m lower than present, and thus is not in equilibrium with present recharge conditions. Here we show that the geochemistry of the groundwater found in the Floridan Aquifer System in south Florida ...

  6. Effects of climate change on groundwater: observed and forecasted trends on Italian systems

    Science.gov (United States)

    Doveri, Marco; Menichini, Matia; Provenzale, Antonello; Scozzari, Andrea

    2017-04-01

    Groundwater represents the main source of water supply at global level. In Italy, as well as in most European countries, water needs are mainly covered by groundwater exploitation. The reliance on this resource is continuously growing, given the key role that groundwater plays for mitigating the climate change/variability and for addressing the significant increase in the global water demand. Despite this, and unlike surface waters, groundwater bodies have not been widely studied, and there is a general paucity of quantitative information, especially in relation to climate change. Although groundwater systems are more resilient to climate change than surface waters, they are affected both directly and indirectly. The estimation of the entity of these effects is mandatory for a reliable management of this crucial resource. The analysis of hydro-meteorological data over a few decades highlights that also the Italian territory is experiencing a change of the climate regime. Besides the increase of mean annual temperature, observed in particular since the early 1980s, longer and more frequent drought periods have been registered, as well as an increase of extreme events characterized by heavy rainfall. It is also noticeable a decrease in total rainfall, that is much more evident in the period from January to June. In addition to the reduced yearly inputs from precipitation, such trends determine also a lower snow accumulation and earlier snow melt in mountain areas, a general increase of evapotranspiration rates and an increased runoff fraction of the effective rainfall amount. As flood hydrographs of several major Italian rivers (e.g., Po, Brenta and Arno rivers) confirm, evident effects concern surface water resources. The main observed phenomena consist in the decline of mean annual discharge, the increase of extreme events with high discharge concentrated in short periods, and longer and earlier periods of low base flow. Impacts on groundwater recharge are not well

  7. Comparison of a Conceptual Groundwater Model and Physically Based Groundwater Mode

    Science.gov (United States)

    Yang, J.; Zammit, C.; Griffiths, J.; Moore, C.; Woods, R. A.

    2017-12-01

    Groundwater is a vital resource for human activities including agricultural practice and urban water demand. Hydrologic modelling is an important way to study groundwater recharge, movement and discharge, and its response to both human activity and climate change. To understand the groundwater hydrologic processes nationally in New Zealand, we have developed a conceptually based groundwater flow model, which is fully integrated into a national surface-water model (TopNet), and able to simulate groundwater recharge, movement, and interaction with surface water. To demonstrate the capability of this groundwater model (TopNet-GW), we applied the model to an irrigated area with water shortage and pollution problems in the upper Ruamahanga catchment in Great Wellington Region, New Zealand, and compared its performance with a physically-based groundwater model (MODFLOW). The comparison includes river flow at flow gauging sites, and interaction between groundwater and river. Results showed that the TopNet-GW produced similar flow and groundwater interaction patterns as the MODFLOW model, but took less computation time. This shows the conceptually-based groundwater model has the potential to simulate national groundwater process, and could be used as a surrogate for the more physically based model.

  8. Applying a System Dynamics Approach for Modeling Groundwater Dynamics to Depletion under Different Economical and Climate Change Scenarios

    Directory of Open Access Journals (Sweden)

    Hamid Balali

    2015-09-01

    Full Text Available In the recent decades, due to many different factors, including climate change effects towards be warming and lower precipitation, as well as some structural policies such as more intensive harvesting of groundwater and low price of irrigation water, the level of groundwater has decreased in most plains of Iran. The objective of this study is to model groundwater dynamics to depletion under different economic policies and climate change by using a system dynamics approach. For this purpose a dynamic hydro-economic model which simultaneously simulates the farmer’s economic behavior, groundwater aquifer dynamics, studied area climatology factors and government economical policies related to groundwater, is developed using STELLA 10.0.6. The vulnerability of groundwater balance is forecasted under three scenarios of climate including the Dry, Nor and Wet and also, different scenarios of irrigation water and energy pricing policies. Results show that implementation of some economic policies on irrigation water and energy pricing can significantly affect on groundwater exploitation and its volume balance. By increasing of irrigation water price along with energy price, exploitation of groundwater will improve, in so far as in scenarios S15 and S16, studied area’s aquifer groundwater balance is positive at the end of planning horizon, even in Dry condition of precipitation. Also, results indicate that climate change can affect groundwater recharge. It can generally be expected that increases in precipitation would produce greater aquifer recharge rates.

  9. Water Conservation and Artificial Recharge of Aquifers in India

    Energy Technology Data Exchange (ETDEWEB)

    Chandha, D. K.

    2014-10-01

    India has proud traditions and wisdom which have evolved over thousands of years for developing technologies for water conservation and groundwater recharge using surplus monsoon precipitation runoff. This is imperative as the average rainfall/precipitation period is about 27 days/year and with uneven distribution across the country. Groundwater development is now the mainstay for sustaining agricultural production and rural water supplies. As such, groundwater development is increasing at an exponential rate and the estimated draft is now 231 000 hm{sup 3} with the result that almost 15% of the groundwater development areas are showing a continuous decline of water levels. There is an anomalous situation whereby water levels are declining in 831 blocks (assessment units) out of a total of 5 723 blocks across the country, and availability of excessive 864 000 hm{sup 3} runoff in different river basins brings floods and creates water logging in some parts of the country. This non-utilizable water can be planned for creating small surface water storage and to create additional sub-surface storage through groundwater recharge. At present, total water available is estimated at 660 000 hm{sup 3} and the minimum estimated water demand will be 843 000 hm{sup 3} in 2025 and 973 000 hm{sup 3} in 2050. Therefore, if India wants sustainable food supplies and to meet domestic/industrial water requirements, there is no other option than to implement projects for water conservation/groundwater recharge. Although a number of forward looking steps have been planned by the government and other institutions, many lacunae have been observed which need to be addressed for the successful implementation of water conservation and recharge programmes. This paper discusses various practices from the pre-historic to the present day, with case studies showing technological intervention. (Author)

  10. Seasonal Variation of Infiltration Rates in a Managed Aquifer Recharge System: A Belgian Example

    Science.gov (United States)

    Samanta, S.; Sheng, Z.; Munster, C. L.; Houtte, E. V.

    2017-12-01

    Managed Aquifer Recharge (MAR) is a powerful tool in addressing water resources management issues. The Torreele water reuse facility is using MAR to address the problem of water sustainability in a coastal aquifer of Belgium. The Torreele MAR facility uses infiltration ponds to maintain the groundwater level and to prevent saltwater intrusion into the aquifer. The source of recharge is treated wastewater from the Torreele wastewater treatment plant (TWWTP) located 1.2 km inland. The TWWTP uses a state-of-the-art filtration mechanism with a combination of ultrafiltration (UF) and Reverse Osmosis (RO) techniques to assure that recharge water is of very high quality. Data collected at the Torreele MAR facility indicates reduced infiltration rates during the winter season when pond water temperatures vary from 1 to 10ºC. The proposed hypothesis for these lower infiltration rates may be a reduction in hydraulic conductivity due to changes in water viscosity. This study involves the determination of relationship between water temperature, infiltration rates, and hydraulic conductivity at the Torreele MAR facility. The results of this study will lead to an effective administration of the facility and provide an extensive understanding of the system.

  11. Groundwater availability of the Mississippi embayment

    Science.gov (United States)

    Clark, Brian R.; Hart, Rheannon M.; Gurdak, Jason J.

    2011-01-01

    River Valley alluvial aquifer in Arkansas, Louisiana, Mississippi, and Missouri, and to a lesser extent in Illinois, Kentucky, and Tennessee. Predevelopment groundwater flow is represented in the MERAS model as a steady-state stress period, assumed to be prior to 1870. The simulated groundwater-flow budget indicates the largest predevelopment inflow to the system is net recharge to the alluvial aquifer. This inflow is balanced by outflow to gaining streams. Overall, water enters as net recharge to the alluvial aquifer or through outcrop areas of the various hydrogeologic units. Away from the outcrop areas, groundwater flow in the deeper formations is primarily upward into overlying units, ultimately discharging to streams through the alluvial aquifer. Total net recharge and discharge (sum of inflows or outflows) for the model ranged from about 0.66 million acre-feet per year during predevelopment to 20.16 million acre-feet per year by the end of the simulation (final simulated irrigation period in summer of 2006). This change in the model budget reflects increases in withdrawals compared to predevelopment conditions. Cumulative storage within aquifers simulated in the MERAS model indicates overall depletion of 140 million acre-feet (equivalent to 2.8 feet of water covering the entire study area). Postdevelopment inflow to the system is still through net recharge to the alluvial aquifer and the outcrop areas of the several hydrogeologic units, however, the flow between each unit is no longer upward to the alluvial aquifer. Groundwater flow during the summer of 2006 was primarily downward to offset demand from pumping. Early in the model simulation (1870-1920s), the primary components of the water budget were simulated as outflow from stream leakage and inflow from net recharge. As pumpage increased through time, water that would otherwise flow to streams reversed, and net stream leakage became an inflow to the system. The largest reversals began in the mid-1980s, but

  12. Simulated groundwater flow paths, travel time, and advective transport of nitrogen in the Kirkwood-Cohansey aquifer system, Barnegat Bay–Little Egg Harbor Watershed, New Jersey

    Science.gov (United States)

    Voronin, Lois M.; Cauller, Stephen J.

    2017-07-31

    Elevated concentrations of nitrogen in groundwater that discharges to surface-water bodies can degrade surface-water quality and habitats in the New Jersey Coastal Plain. An analysis of groundwater flow in the Kirkwood-Cohansey aquifer system and deeper confined aquifers that underlie the Barnegat Bay–Little Egg Harbor (BB-LEH) watershed and estuary was conducted by using groundwater-flow simulation, in conjunction with a particle-tracking routine, to provide estimates of groundwater flow paths and travel times to streams and the BB-LEH estuary.Water-quality data from the Ambient Groundwater Quality Monitoring Network, a long-term monitoring network of wells distributed throughout New Jersey, were used to estimate the initial nitrogen concentration in recharge for five different land-use classes—agricultural cropland or pasture, agricultural orchard or vineyard, urban non-residential, urban residential, and undeveloped. Land use at the point of recharge within the watershed was determined using a geographic information system (GIS). Flow path starting locations were plotted on land-use maps for 1930, 1973, 1986, 1997, and 2002. Information on the land use at the time and location of recharge, time of travel to the discharge location, and the point of discharge were determined for each simulated flow path. Particle-tracking analysis provided the link from the point of recharge, along the particle flow path, to the point of discharge, and the particle travel time. The travel time of each simulated particle established the recharge year. Land use during the year of recharge was used to define the nitrogen concentration associated with each flow path. The recharge-weighted average nitrogen concentration for all flow paths that discharge to the Toms River upstream from streamflow-gaging station 01408500 or to the BB-LEH estuary was calculated.Groundwater input into the Barnegat Bay–Little Egg Harbor estuary from two main sources— indirect discharge from base

  13. Groundwater geochemistry of nile delta-desert interface 1.isotope hydrology

    Energy Technology Data Exchange (ETDEWEB)

    Hussein, M F [Cairo University, Dept., of Soil and water, Giza, Gamma Street, (Egypt); Nada, A A; Awad, M A [Atomic Energy Authority, Nuclear Chemistry Dept., P.o. Box 13759, Cairo, (Egypt)

    1995-10-01

    Sustenance and environmental protection of groundwater supply is of major concern in the integral environmental development in the arid to sub-arid regions in the Nile basin. Isotope data ({sup 18O}, {sup 2H} and {sup 3H}) of groundwater in the west of the Nile delta indicates the contribution of palaeo groundwater component (in the range 0.1 - 0.8 with means of 0.39 and 0.52 for tahrir and khatatbah, respectively) along with sub recent recharge from the delta aquifer and recent recharge from irrigation conveyance canals in desert. Isotope mixing model (developed as Two-input table using excel{sup TM} spreads heat on apple Macintosh{sup TM)} is proposed to explain the apparent discrepancies in groundwater isotopic composition of khatatbah and tahrir areas assuming the contribution of two isotopically different palaeo-oples with two isotopically similar maind delta groundwater poles. About 0.30% {sup 1}8{sup O} depletion per 10 Km downstream is detected and low northward groundwater recharge is suggested along 75 Km of the western strip of rosetta Nile. Higher sub-recent recharge from the main delta aquifer is believed to take place in khatatbah than tahrir whereas the last is believed to be replenished at present from the irrigation/ drainage network and irrigated fields with higher pollution risk for groundwater system in tahrir aquifer is exposed to northern marine intrusion. Lowering of the piezo metric level is to be expected in the newly exploited desertic areas under over pumping. 9 figs.

  14. Determining Changes in Groundwater Quality during Managed Aquifer Recharge

    Science.gov (United States)

    Gambhir, T.; Houlihan, M.; Fakhreddine, S.; Dadakis, J.; Fendorf, S. E.

    2016-12-01

    Managed aquifer recharge (MAR) is becoming an increasingly prevalent technology for improving the sustainability of freshwater supply. However, recharge water can alter the geochemical conditions of the aquifer, mobilizing contaminants native to the aquifer sediments. Geochemical alterations on deep (>300 m) injection of highly treated recycled wastewater for MAR has received limited attention. We aim to determine how residual disinfectants used in water treatment processes, specifically the strong oxidants chloramine and hydrogen peroxide, affect metal mobilization within deep injection wells of the Orange County Water District. Furthermore, as the treated recharge water has very low ionic strength (44.6 mg L-1 total dissolved solids), we tested how differing concentrations of magnesium chloride and calcium chloride affected metal mobilization within deep aquifers. Continuous flow experiments were conducted on columns dry packed with sediments from a deep injection MAR site in Orange County, CA. The effluent was analyzed for shifts in water quality, including aqueous concentrations of arsenic, uranium, and chromium. Interaction between the sediment and oxic recharge solution causes naturally-occurring arsenopyrite to repartition onto iron oxides. The stability of arsenic on the newly precipitated iron oxides is dependent on pH changes during recharge.

  15. Reconnaissance Estimates of Recharge Based on an Elevation-dependent Chloride Mass-balance Approach

    Energy Technology Data Exchange (ETDEWEB)

    Charles E. Russell; Tim Minor

    2002-08-31

    Significant uncertainty is associated with efforts to quantity recharge in arid regions such as southern Nevada. However, accurate estimates of groundwater recharge are necessary to understanding the long-term sustainability of groundwater resources and predictions of groundwater flow rates and directions. Currently, the most widely accepted method for estimating recharge in southern Nevada is the Maxey and Eakin method. This method has been applied to most basins within Nevada and has been independently verified as a reconnaissance-level estimate of recharge through several studies. Recharge estimates derived from the Maxey and Eakin and other recharge methodologies ultimately based upon measures or estimates of groundwater discharge (outflow methods) should be augmented by a tracer-based aquifer-response method. The objective of this study was to improve an existing aquifer-response method that was based on the chloride mass-balance approach. Improvements were designed to incorporate spatial variability within recharge areas (rather than recharge as a lumped parameter), develop a more defendable lower limit of recharge, and differentiate local recharge from recharge emanating as interbasin flux. Seventeen springs, located in the Sheep Range, Spring Mountains, and on the Nevada Test Site were sampled during the course of this study and their discharge was measured. The chloride and bromide concentrations of the springs were determined. Discharge and chloride concentrations from these springs were compared to estimates provided by previously published reports. A literature search yielded previously published estimates of chloride flux to the land surface. {sup 36}Cl/Cl ratios and discharge rates of the three largest springs in the Amargosa Springs discharge area were compiled from various sources. This information was utilized to determine an effective chloride concentration for recharging precipitation and its associated uncertainty via Monte Carlo simulations

  16. Evaluating the performance of water purification in a vegetated groundwater recharge basin maintained by short-term pulsed infiltration events.

    Science.gov (United States)

    Mindl, Birgit; Hofer, Julia; Kellermann, Claudia; Stichler, Willibald; Teichmann, Günter; Psenner, Roland; Danielopol, Dan L; Neudorfer, Wolfgang; Griebler, Christian

    2015-01-01

    Infiltration of surface water constitutes an important pillar in artificial groundwater recharge. However, insufficient transformation of organic carbon and nutrients, as well as clogging of sediments often cause major problems. The attenuation efficiency of dissolved organic carbon (DOC), nutrients and pathogens versus the risk of bioclogging for intermittent recharge were studied in an infiltration basin covered with different kinds of macrovegetation. The quality and concentration of organic carbon, major nutrients, as well as bacterial biomass, activity and diversity in the surface water, the porewater, and the sediment matrix were monitored over one recharge period. Additionally, the numbers of viral particles and Escherichia coli were assessed. Our study showed a fast establishment of high microbial activity. DOC and nutrients have sustainably been reduced within 1.2 m of sediment passage. Numbers of E. coli, which were high in the topmost centimetres of sediment porewater, dropped below the detection limit. Reed cover was found to be advantageous over bushes and trees, since it supported higher microbial activities along with a good infiltration and purification performance. Short-term infiltration periods of several days followed by a break of similar time were found suitable for providing high recharge rates, and good water purification without the risk of bioclogging.

  17. Groundwater reorganization in the Floridan aquifer following Holocene sea-level rise

    Science.gov (United States)

    Morrissey, Sheila K.; Clark, Jordan F.; Bennett, Michael; Richardson, Emily; Stute, Martin

    2010-10-01

    Sea-level fluctuations, particularly those associated with glacial-interglacial cycles, can have profound impacts on the flow and circulation of coastal groundwater: the water found at present in many coastal aquifers may have been recharged during the last glacial period, when sea level was over 100m lower than present, and thus is not in equilibrium with present recharge conditions. Here we show that the geochemistry of the groundwater found in the Floridan Aquifer System in south Florida is best explained by a reorganization of groundwater flow following the sea-level rise at the end of the Last Glacial Maximum approximately 18,000 years ago. We find that the geochemistry of the fresh water found in the upper aquifers at present is consistent with recharge from meteoric water during the last glacial period. The lower aquifer, however, consists of post-sea-level-rise salt water that is most similar to that of the Straits of Florida, though with some dilution from the residual fresh water from the last glacial period circulation. We therefore suggest that during the last glacial period, the entire Floridan Aquifer System was recharged with meteoric waters. After sea level rose, the increased hydraulic head reduced the velocity of the groundwater flow. This velocity reduction trapped the fresh water in the upper aquifers and initiated saltwater circulation in the lower aquifer.

  18. Budgets and chemical characterization of groundwater for the Diamond Valley flow system, central Nevada, 2011–12

    Science.gov (United States)

    Berger, David L.; Mayers, C. Justin; Garcia, C. Amanda; Buto, Susan G.; Huntington, Jena M.

    2016-07-29

    The Diamond Valley flow system consists of six hydraulically connected hydrographic areas in central Nevada. The general down-gradient order of the areas are southern and northern Monitor Valleys, Antelope Valley, Kobeh Valley, Stevens Basin, and Diamond Valley. Groundwater flow in the Diamond Valley flow system terminates at a large playa in the northern part of Diamond Valley. Concerns relating to continued water-resources development of the flow system resulted in a phased hydrologic investigation that began in 2005 by the U.S. Geological Survey in cooperation with Eureka County. This report presents the culmination of the phased investigation to increase understanding of the groundwater resources of the basin-fill aquifers in the Diamond Valley flow system through evaluations of groundwater chemistry and budgets. Groundwater chemistry was characterized using major ions and stable isotopes from groundwater and precipitation samples. Groundwater budgets accounted for all inflows, outflows, and changes in storage, and were developed for pre-development (pre-1950) and recent (average annual 2011–12) conditions. Major budget components include groundwater discharge by evapotranspiration and groundwater withdrawals; groundwater recharge by precipitation, and interbasin flow; and storage change.

  19. Assessment of Managed Aquifer Recharge through Modeling—A Review

    Directory of Open Access Journals (Sweden)

    Jana Ringleb

    2016-12-01

    Full Text Available Managed aquifer recharge (MAR is the purposeful recharge of an aquifer for later recovery or environmental benefits and represents a valuable method for sustainable water resources management. Models can be helpful tools for the assessment of MAR systems. This review encompasses a survey and an analysis of case studies which apply flow and transport models to evaluate MAR. The observed modeling objectives include the planning or optimization of MAR schemes as well as the identification and quantification of geochemical processes during injection, storage and recovery. The water recovery efficiency and the impact of the injected water on the ambient groundwater are further objectives investigated in the reviewed studies. These objectives are mainly solved by using groundwater flow models. Unsaturated flow models, solute transport models, reactive geochemical models as well as water balance models are also frequently applied and often coupled. As each planning step to setup a new MAR facility requires cost and time investment, modeling is used to minimize hazard risks and assess possible constraints of the system such as low recovery efficiency, clogging and geochemical processes.

  20. Hydrogeology and sustainable future groundwater abstraction from the Agua Verde aquifer in the Atacama Desert, northern Chile

    Science.gov (United States)

    Urrutia, Javier; Jódar, Jorge; Medina, Agustín; Herrera, Christian; Chong, Guillermo; Urqueta, Harry; Luque, José A.

    2018-03-01

    The hyper-arid conditions prevailing in Agua Verde aquifer in northern Chile make this system the most important water source for nearby towns and mining industries. Due to the growing demand for water in this region, recharge is investigated along with the impact of intense pumping activity in this aquifer. A conceptual model of the hydrogeological system is developed and implemented into a two-dimensional groundwater-flow numerical model. To assess the impact of climate change and groundwater extraction, several scenarios are simulated considering variations in both aquifer recharge and withdrawals. The estimated average groundwater lateral recharge from Precordillera (pre-mountain range) is about 4,482 m3/day. The scenarios that consider an increase of water withdrawal show a non-sustainable groundwater consumption leading to an over-exploitation of the resource, because the outflows surpasses inflows, causing storage depletion. The greater the depletion, the larger the impact of recharge reduction caused by the considered future climate change. This result indicates that the combined effects of such factors may have a severe impact on groundwater availability as found in other groundwater-dependent regions located in arid environments. Furthermore, the scenarios that consider a reduction of the extraction flow rate show that it may be possible to partially alleviate the damage already caused to the aquifer by the continuous extractions since 1974, and it can partially counteract climate change impacts on future groundwater availability caused by a decrease in precipitation (and so in recharge), if the desalination plant in Taltal increases its capacity.

  1. The tritium content of precipitation and groundwater at Yola, Nigeria ...

    African Journals Online (AJOL)

    Tritium is a radioactive isotope of hydrogen which occurs in precipitation. In groundwater studies tritium measurements give information on the time of recharge to the system; the tritium content of precipitation being used to estimate the input of tritium to the groundwater system. At Yola, the tritium ontents in precipitation and ...

  2. Groundwater recharge in irrigated semi-arid areas: quantitative hydrological modelling and sensitivity analysis

    Science.gov (United States)

    Jiménez-Martínez, Joaquín; Candela, Lucila; Molinero, Jorge; Tamoh, Karim

    2010-12-01

    For semi-arid regions, methods of assessing aquifer recharge usually consider the potential evapotranspiration. Actual evapotranspiration rates can be below potential rates for long periods of time, even in irrigated systems. Accurate estimations of aquifer recharge in semi-arid areas under irrigated agriculture are essential for sustainable water-resources management. A method to estimate aquifer recharge from irrigated farmland has been tested. The water-balance-modelling approach was based on VisualBALAN v. 2.0, a computer code that simulates water balance in the soil, vadose zone and aquifer. The study was carried out in the Campo de Cartagena (SE Spain) in the period 1999-2008 for three different groups of crops: annual row crops (lettuce and melon), perennial vegetables (artichoke) and fruit trees (citrus). Computed mean-annual-recharge values (from irrigation+precipitation) during the study period were 397 mm for annual row crops, 201 mm for perennial vegetables and 194 mm for fruit trees: 31.4, 20.7 and 20.5% of the total applied water, respectively. The effects of rainfall events on the final recharge were clearly observed, due to the continuously high water content in soil which facilitated the infiltration process. A sensitivity analysis to assess the reliability and uncertainty of recharge estimations was carried out.

  3. Groundwater Recharge, Evapotranspiration and Surface Runoff ...

    African Journals Online (AJOL)

    Bheema

    Using WetSpass Modeling Method in Illala Catchment, Northern Ethiopia ... Recharge is estimated by chloride ion mass balance method, empirical method, ..... environmental conditions of the catchment by applying some soil and water ... meteorological data in Ethiopia: Journal of engineers and architects, Addis Ababa,.

  4. Characterization of a managed aquifer recharge system using multiple tracers.

    Science.gov (United States)

    Moeck, Christian; Radny, Dirk; Popp, Andrea; Brennwald, Matthias; Stoll, Sebastian; Auckenthaler, Adrian; Berg, Michael; Schirmer, Mario

    2017-12-31

    Knowledge about the residence times of artificially infiltrated water into an aquifer and the resulting flow paths is essential to developing groundwater-management schemes. To obtain this knowledge, a variety of tracers can be used to study residence times and gain information about subsurface processes. Although a variety of tracers exists, their interpretation can differ considerably due to subsurface heterogeneity, underlying assumptions, and sampling and analysis limitations. The current study systematically assesses information gained from seven different tracers during a pumping experiment at a site where drinking water is extracted from an aquifer close to contaminated areas and where groundwater is artificially recharged by infiltrating surface water. We demonstrate that the groundwater residence times estimated using dye and heat tracers are comparable when the thermal retardation for the heat tracer is considered. Furthermore, major ions, acesulfame, and stable isotopes (δ 2 H and δ 18 O) show that mixing of infiltrated water and groundwater coming from the regional flow path occurred and a vertical stratification of the flow system exist. Based on the concentration patterns of dissolved gases (He, Ar, Kr, N 2 , and O 2 ) and chlorinated solvents (e.g., tetrachloroethene), three temporal phases are observed in the ratio between infiltrated water and regional groundwater during the pumping experiment. Variability in this ratio is significantly related to changes in the pumping and infiltration rates. During constant pumping rates, more infiltrated water was extracted, which led to a higher dilution of the regional groundwater. An infiltration interruption caused however, the ratio to change and more regional groundwater is extracted, which led to an increase in all concentrations. The obtained results are discussed for each tracer considered and its strengths and limitations are illustrated. Overall, it is demonstrated that aquifer heterogeneity and

  5. Climate variability and vadose zone controls on damping of transient recharge

    Science.gov (United States)

    Corona, Claudia R.; Gurdak, Jason J.; Dickinson, Jesse; Ferré, T.P.A.; Maurer, Edwin P.

    2017-01-01

    Increasing demand on groundwater resources motivates understanding of the controls on recharge dynamics so model predictions under current and future climate may improve. Here we address questions about the nonlinear behavior of flux variability in the vadose zone that may explain previously reported teleconnections between global-scale climate variability and fluctuations in groundwater levels. We use hundreds of HYDRUS-1D simulations in a sensitivity analysis approach to evaluate the damping depth of transient recharge over a range of periodic boundary conditions and vadose zone geometries and hydraulic parameters that are representative of aquifer systems of the conterminous United States (U.S). Although the models were parameterized based on U.S. aquifers, findings from this study are applicable elsewhere that have mean recharge rates between 3.65 and 730 mm yr–1. We find that mean infiltration flux, period of time varying infiltration, and hydraulic conductivity are statistically significant predictors of damping depth. The resulting framework explains why some periodic infiltration fluxes associated with climate variability dampen with depth in the vadose zone, resulting in steady-state recharge, while other periodic surface fluxes do not dampen with depth, resulting in transient recharge. We find that transient recharge in response to the climate variability patterns could be detected at the depths of water levels in most U.S. aquifers. Our findings indicate that the damping behavior of transient infiltration fluxes is linear across soil layers for a range of texture combinations. The implications are that relatively simple, homogeneous models of the vadose zone may provide reasonable estimates of the damping depth of climate-varying transient recharge in some complex, layered vadose zone profiles.

  6. Effects of Land-Use Change and Managed Aquifer Recharge on Geochemical Reactions with Implications for Groundwater Quantity and Quality in Atoll Island Aquifers, Roi-Namur, Republic of the Marshall Islands

    Science.gov (United States)

    Hejazian, M.; Swarzenski, P. W.; Gurdak, J. J.; Odigie, K. O.; Storlazzi, C. D.

    2015-12-01

    This study compares the hydrogeochemistry of two contrasting atoll groundwater systems in Roi-Namur, Republic of the Marshall Islands. Roi-Namur houses a U.S. Department of Defense military installation and presents an ideal study location where a human impacted aquifer is co-located next to a natural aquifer as part of two artificially conjoined atoll islands. The hydrogeology and geochemistry of carbonate atoll aquifers has been well studied, particularly because of its small, well-defined hydrologic system that allows for relatively precise modeling. However, it is unknown how changes in land-use/land cover and managed aquifer recharge (MAR) alters natural geochemical processes in atoll aquifers. A better understanding of this has implications on groundwater quantity and quality, carbonate dissolution, and best aquifer management practices in the context of rising sea level and saltwater intrusion. Roi has been heavily modified to house military and civilian operations; here, lack of vegetation and managed recharge has increased the volume of potable groundwater and affected the geochemical processes in the freshwater lens and saltwater transition zone. Namur is heavily vegetated and the hydrogeology is indicative of a natural atoll island. A suite of monitoring wells were sampled across both island settings for major ions, nutrients, trace elements, DOC/DIC, δ13C and δ18O/2H isotopes. By modeling geochemical reactions using a conservative mixing approach, we measure deviations from expected reactions and compare the two contrasting settings using derived geochemical profiles through a wide salinity spectrum. Results indicate that groundwater on Namur is more heavily depleted in δ13C and has greater dissolved inorganic carbon, suggesting higher microbial oxidation and greater dissolution within the carbonate aquifer. This suggests MAR and reduction of vegetation makes the groundwater supply on atoll islands more resilient to sea level rise.

  7. A study on groundwater infiltration in the Horonobe area, northern Hokkaido, Japan

    International Nuclear Information System (INIS)

    Yokota, Hideharu; Yamamoto, Yoichi; Maekawa, Keisuke; Hara, Minoru

    2011-01-01

    In the Horonobe area of northern Hokkaido, the Japan Atomic Energy Agency has been carrying out various hydrological observations to estimate the recharge rate. Subsurface earth temperature and soil moisture content have been observed at HGW-1 site (GL-0.7m to GL-2.3m, since 2005) and Hokushin Meteorological Station (GL-0.1m to GL-1.1m, since 2008). The results have revealed groundwater infiltration and recharge occurring throughout year, the shallow groundwater-infiltration velocity depending on the depth and the position of the Zero Flux Plane. For the estimation of boundary conditions in groundwater flow simulation, in this study, the shallow groundwater-flow system has been examined qualitatively on the basis of the variation of the subsurface earth temperature and the soil moisture content. In the future, it is necessary to quantitatively assess the shallow groundwater infiltration and recharge rate, the intermediate runoff, and the evapotranspiration based on the observed data of the weighing lysimeter, and the other measurement stations in the area. (author)

  8. Groundwater flow systems in the great Aletsch glacier region (Valais, Switzerland)

    Science.gov (United States)

    Alpiger, Andrea; Loew, Simon

    2014-05-01

    Groundwater flow systems in Alpine areas are often complex and challenging to investigate due to special topographic and climatic conditions governing groundwater recharge and bedrock flow. Studies seeking to characterize high-alpine groundwater systems remain rare, but are of high interest, e.g. for water supply, hydropower systems, traffic tunnels or rock slope deformation and landslide hazards. The goal of this study is to better understand the current and past groundwater flow systems of the UNESCO World Heritage mountain ridge separating the great Aletsch glacier and the Rhone valley, considering climatic and glacier fluctuations during the Lateglacial and Holocene periods. This ridge is crossed by a hydropower bypass drift (Riederhornstollen) and is composed of fractured crystalline rocks overlain by various types of landslides and glacial deposits. Surface hydrology observations (fracture properties, groundwater seepage, spring lines and physico-chemical parameters) and hydropower drift inflow measurements contributed to the characterization of bedrock hydraulic conductivities and preferential groundwater pathways. Basic conceptual hydrogeological models were tested with observed drift inflows and the occurrence of springs using free-surface, variably saturated, vertical 2D groundwater flow models (using the code SEEP/W from GeoStudio 2007). Already simple two-layer models, representing profile sections orthogonal to the mountain ridge, provided useful results. Simulations show that differences in the occurrence of springs on each side of the mountain ridge are likely caused by the occurrence of glacial till (generating perched groundwater), the deep-seated sagging landslide mass, faults and asymmetric ridge topography, which together force the main groundwater flow direction to be oriented towards the Rhone valley, even from beyond the mountain ridge. Surprisingly, the most important springs (those with high discharge rates) are located at high elevations

  9. Ion exchange and trace element surface complexation reactions associated with applied recharge of low-TDS water in the San Joaquin Valley, California

    International Nuclear Information System (INIS)

    McNab, Walt W.; Singleton, Michael J.; Moran, Jean E.; Esser, Bradley K.

    2009-01-01

    Stable isotope data, a dissolved gas tracer study, groundwater age dating, and geochemical modeling were used to identify and characterize the effects of introducing low-TDS recharge water in a shallow aerobic aquifer affected by a managed aquifer recharge project in California's San Joaquin Valley. The data all consistently point to a substantial degree of mixing of recharge water from surface ponds with ambient groundwater in a number of nearby wells screened at depths above 60 m below ground surface. Groundwater age data indicate that the wells near the recharge ponds sample recently recharged water, as delineated by stable O and C isotope data as well as total dissolved solids, in addition to much older groundwater in various mixing proportions. Where the recharge water signature is present, the specific geochemical interactions between the recharge water and the aquifer material appear to include ion exchange reactions (comparative enrichment of affected groundwater with Na and K at the expense of Ca and Mg) and the desorption of oxyanion-forming trace elements (As, V, and Mo), possibly in response to the elevated pH of the recharge water

  10. Catchment-scale groundwater recharge and vegetation water use efficiency

    Science.gov (United States)

    Troch, P. A. A.; Dwivedi, R.; Liu, T.; Meira, A.; Roy, T.; Valdés-Pineda, R.; Durcik, M.; Arciniega, S.; Brena-Naranjo, J. A.

    2017-12-01

    Precipitation undergoes a two-step partitioning when it falls on the land surface. At the land surface and in the shallow subsurface, rainfall or snowmelt can either runoff as infiltration/saturation excess or quick subsurface flow. The rest will be stored temporarily in the root zone. From the root zone, water can leave the catchment as evapotranspiration or percolate further and recharge deep storage (e.g. fractured bedrock aquifer). Quantifying the average amount of water that recharges deep storage and sustains low flows is extremely challenging, as we lack reliable methods to quantify this flux at the catchment scale. It was recently shown, however, that for semi-arid catchments in Mexico, an index of vegetation water use efficiency, i.e. the Horton index (HI), could predict deep storage dynamics. Here we test this finding using 247 MOPEX catchments across the conterminous US, including energy-limited catchments. Our results show that the observed HI is indeed a reliable predictor of deep storage dynamics in space and time. We further investigate whether the HI can also predict average recharge rates across the conterminous US. We find that the HI can reliably predict the average recharge rate, estimated from the 50th percentile flow of the flow duration curve. Our results compare favorably with estimates of average recharge rates from the US Geological Survey. Previous research has shown that HI can be reliably estimated based on aridity index, mean slope and mean elevation of a catchment (Voepel et al., 2011). We recalibrated Voepel's model and used it to predict the HI for our 247 catchments. We then used these predicted values of the HI to estimate average recharge rates for our catchments, and compared them with those estimated from observed HI. We find that the accuracies of our predictions based on observed and predicted HI are similar. This provides an estimation method of catchment-scale average recharge rates based on easily derived catchment

  11. Evaluating Renewable Groundwater Stress with GRACE data in Greece

    Science.gov (United States)

    Lakshmi, V.; Gemitzi, A.

    2016-12-01

    Groundwater is a resilient water source and its importance as a fundamental resource is even greater in times of drought where groundwater stress conditions are greatest for areas like Mediterranean and adverse climate change effects are expected. The present study evaluates Renewable Groundwater Stress (RGS) as the ratio of groundwater use to groundwater availability, quantifying use as the trend in GRACE-derived subsurface anomalies (ΔGWtrend) and renewable groundwater availability as mean annual recharge. Estimates for mean annual recharge were used from groundwater studies conducted for the various regions in Greece, mainly in the form of numerical models. Our results highlighted two RGS regimes in Greece out of the four characteristic stress regimes, i.e. Overstressed, Variable Stress, Human-Dominated Stress and Unstressed, defined as a function of the sign of use and the sign of groundwater availability (positive or negative). Variable Stress areas are found in central Greece (Thessaly region), where intense agricultural activities take place, with negative ΔGWtrend values combined with positive mean annual recharge rates. RGS values range from -0.05 - 0, indicating however a low impact area. Within this region, adverse effects of groundwater overexploitation are already evident, based on the negative GRACE anomalies, recharge however still remains positive, amending the adverse over pumping impacts. The rest of Greek aquifers fall within the unstressed category, with RGS values from 0.02 - 0.05, indicating that the rate of use is less than the natural recharge rate. The highest Unstressed RGS values are observed in Crete Island and in Northeastern Greece. However, the case of Crete is highly uncertain, as precipitation and recharge in this area demonstrate exceptionally high variability and the coarse resolution of GRACE results does not allow for reliable estimates.

  12. Managing Groundwater Recharge and Pumping for Late Summer Streamflow Increases: Quantifying Uncertainty Using Null Space Monte Carlo

    Science.gov (United States)

    Tolley, D. G., III; Foglia, L.; Harter, T.

    2017-12-01

    Late summer and early fall streamflow decreases caused by climate change and agricultural pumping contribute to increased water temperatures and result in large disconnected sections during dry years in many semi-arid regions with Mediterranean climate. This negatively impacts aquatic habitat of fish species such as coho and fall-run Chinook salmon. In collaboration with local stakeholders, the Scott Valley Integrated Hydrologic Model (SVIHMv3) was developed to assess future water management scenarios with the goal of improving aquatic species habitat while maintaining agricultural production in the valley. The Null Space Monte Carlo (NSMC) method available in PEST was used to quantify the range of predicted streamflow changes for three conjunctive use scenarios: 1) managed aquifer recharge (MAR), 2) in lieu recharge (ILR, substituting surface-water irrigation for irrigation with groundwater while flows are available), and 3) MAR + ILR. Random parameter sets were generated using the calibrated covariance matrix of the model, which were then recalibrated if the sum of squared residuals was greater than 10% of the original sum of squared weighted residuals. These calibration-constrained stochastic parameter sets were then used to obtain a distribution of streamflow changes resulting from implementing the conjunctive use scenarios. Preliminary results show that while the range of streamflow increases using managed aquifer recharge is much narrower (i.e., greater degree of certainty) than in lieu recharge, there are potentially much greater benefits to streamflow by implementing in lieu recharge (although also greater costs). Combining the two scenarios provides the greatest benefit for increasing late summer and early fall streamflow, as most of the MAR streamflow increases are during the spring and early summer which ILR is able to take advantage of. Incorporation of uncertainty into model predictions is critical for establishing and maintaining stakeholder trust

  13. Decision Support System for Aquifer Recharge (AR) and Aquifer Storage and Recovery (ASR) Planning, Design, and Evaluation - Principles and Technical Basis

    Science.gov (United States)

    Aquifer recharge (AR) is a technical method being utilized to enhance groundwater resources through man-made replenishment means, such as infiltration basins and injections wells. Aquifer storage and recovery (ASR) furthers the AR techniques by withdrawal of stored groundwater at...

  14. Preferential flow and mixing process in the chemical recharge in subsurface catchments: observations and modeling

    Science.gov (United States)

    Gascuel-Odoux, C.; Rouxel, M.; Molenat, J.; Ruiz, L.; Aquilina, L.; Faucheux, M.; Labasque, T.; Sebilo, M.

    2012-04-01

    Shallow groundwater that develops on hillslopes is the main compartment in headwater catchments for flow and solute transport to rivers. Although spatial and temporal variations in its chemical composition are reported in the literature, there is no coherent description of the way these variations are organized, nor is there an accepted conceptual model for the recharge mechanisms and flows in the groundwater involved. We instrumented an intensive farming and subsurface dominant catchment located in Oceanic Western Europe (Kerbernez, Brittany, France), a headwater catchment included in the Observatory for Research on Environment AgrHyS (Agro-Hydro-System) and a part of the French Network of catchments for environmental research (SOERE RBV focused on the Critical Zone). These systems are strongly constrained by anthropogenic pressures (agriculture) and are characterized by a clear non-equilibrium status. A network of 42 nested piezometers was installed along a 200 m hillslope allowing water sampling along two transects in the permanent water table as well as in what we call the "fluctuating zone", characterized by seasonal alternance of saturated and unsaturated conditions. Water composition was monitored at high frequency (weekly) over a 3-year period for major anion composition and over a one year period for detailed 15N, CFC, SF6 and other dissolved gases. The results demonstrated that (i) the anionic composition in water table fluctuation zone varied significantly compared to deeper portions of the aquifer on the hillslope, confirming that this layer constitutes a main compartment for the mixing of new recharge water and old groundwater, (ii) seasonally, the variations of 15N and CFC are much higher during the recharge period than during the recession period, confirming the preferential flow during early recharge events, iii) variations of nitrate 15N and O18 composition was suggesting any significant denitrification process in the fluctuating zone, confirming

  15. Modeling Recharge - can it be Done?

    Science.gov (United States)

    Verburg, K.; Bond, W. J.; Smith, C. J.; Dunin, F. X.

    2001-12-01

    In sub-humid areas where rainfall is relatively low and sporadic, recharge (defined as water movement beyond the active root zone) is the small difference between the much larger numbers rainfall and evapotranspiration. It is very difficult to measure and often modeling is resorted to instead. But is modeling this small number any less difficult than measurement? In Australia there is considerable debate over the magnitude of recharge under different agricultural systems because of its contribution to rising saline groundwater levels following the clearing of native vegetation in the last 100 years. Hence the adequacy of measured and modeled estimates of recharge is under close scrutiny. Results will be presented for the water balance of an intensively monitored 8 year sequence of crops and pastures. Measurements included meteorological inputs, evapotranspiration measured with a pair of weighing lysimeters, and soil water content was measured with TDR and neutron moisture meter. Recharge was estimated from the percolate removed from the lysimeters as well as, when conditions were suitable, from soil water measurements and combined soil water and evapotranspiration measurements. This data was simulated using a comprehensive soil-plant-atmosphere model (APSIM). Comparison with field measurements shows that the recharge can be simulated with an accuracy similar to that with which it can be measured. However, is either sufficiently accurate for the applications for which they are required?

  16. Managed aquifer recharge experiences with shallow wells: first analysis of the experimental activities in the high Vicenza plain (Northern Italy

    Directory of Open Access Journals (Sweden)

    Lorenzo Altissimo

    2014-09-01

    Full Text Available In recent decades, groundwater resources of the high Vicenza plain were subjected to an increasing extraction rate and, at the same time, to a lower quantity of groundwater recharge. The result is a decreasing flow from the plain springs and a high reduction in piezometric levels of the middle and lower Venetian aquifers. In order to restore the balance of groundwater resources in the Vicenza area, the Vicenza Province has promoted experimental activities aimed to increase the recharge of the aquifer in the high Vicenza plain and in the River Agno valley, using infiltration wells, forested infiltration areas, infiltration trenches, subsurface fields and infiltration canals. All recharge plants are fed by irrigation water, managed by agricultural consortia only during periods of water surplus. Construction works were preceded by specific geological and hydrogeological investigations to verify the suitability for recharge, with the purpose of optimizing the available economic resources. For the protection of the aquifer system, a chemical background of infiltration water was assessed with periodical chemical-physical and microbiological surveys. After the activation date, a monthly monitoring program started to verify the quality of both surface and groundwater, collecting samples in monitoring wells downstream the infiltration structures. The input flow rate entering the various systems, monitored by automatic instruments either in the superficial structure and in groundwater, have provided interesting information about the volumes and the quality of water. These scientific experiences appear to be very helpful in case of future applications for other sites, especially during critical hydrologic period.

  17. A generalized regression model of arsenic variations in the shallow groundwater of Bangladesh

    Science.gov (United States)

    Taylor, Richard G.; Chandler, Richard E.

    2015-01-01

    Abstract Localized studies of arsenic (As) in Bangladesh have reached disparate conclusions regarding the impact of irrigation‐induced recharge on As concentrations in shallow (≤50 m below ground level) groundwater. We construct generalized regression models (GRMs) to describe observed spatial variations in As concentrations in shallow groundwater both (i) nationally, and (ii) regionally within Holocene deposits where As concentrations in groundwater are generally high (>10 μg L−1). At these scales, the GRMs reveal statistically significant inverse associations between observed As concentrations and two covariates: (1) hydraulic conductivity of the shallow aquifer and (2) net increase in mean recharge between predeveloped and developed groundwater‐fed irrigation periods. Further, the GRMs show that the spatial variation of groundwater As concentrations is well explained by not only surface geology but also statistical interactions (i.e., combined effects) between surface geology and mean groundwater recharge, thickness of surficial silt and clay, and well depth. Net increases in recharge result from intensive groundwater abstraction for irrigation, which induces additional recharge where it is enabled by a permeable surface geology. Collectively, these statistical associations indicate that irrigation‐induced recharge serves to flush mobile As from shallow groundwater. PMID:27524841

  18. Cation exchange and CaCO 3 dissolution during artificial recharge of effluent to a calcareous sandstone aquifer

    Science.gov (United States)

    Goren, Orly; Gavrieli, Ittai; Burg, Avihu; Lazar, Boaz

    2011-03-01

    SummaryThis research describes a field study and laboratory simulations of the geochemical evolution of groundwater following a recharge of effluent into aquifers. The study was conducted in the soil aquifer treatment (SAT) system of the Shafdan sewage reclamation plant, Israel. The SAT system recharges secondary effluent into the calcareous sandstone sediments of the Israeli Coastal Aquifer as a tertiary treatment. The reclaimed effluent is recovered ca. 500 m off the recharge basin and is used for unlimited irrigation. The laboratory simulations in which effluent was pumped through experimental columns packed with pristine Shafdan sediment showed that the chemical composition of the outflowing water was controlled mainly by cation exchange and CaCO 3 dissolution. Na +, K + and Mg 2+ were adsorbed and Ca 2+ was desorbed during the initial stage of recharge. The equilibrium distribution of the adsorbed cations was: Ca 2+ ˜ 60%, Mg 2+ ˜ 20%, and Na + and K + ˜ 10% each. The Ca 2+ in the Shafdan production wells and in the experimental columns outflow (˜5 meq L -1) was always higher than the Ca 2+ in the recharged effluent (˜3.5 meq L -1), indicating continuous CaCO 3 dissolution. This study demonstrates that besides mixing, a suite of geochemical processes should be considered when assessing groundwater quality following artificial recharge of aquifers.

  19. Environmental isotope studies on groundwater problems in the Thar Desert, India

    International Nuclear Information System (INIS)

    Nair, A.R.; Navada, S.V.; Rao, S.M.

    1997-01-01

    One of the groundwater problems encountered in arid areas like the Thar Desert in Rajasthan is to know whether the shallow groundwater is being actively recharged. Environmental isotopes particularly tritium are very useful in providing evidence of recent recharge. In the Barmer area, the shallow groundwaters have tritium levels generally in the range 3-6 TU showing modern recharge. Most of the recharge possibly occurs by direct infiltration of precipitation. Indirect recharge through wadis (river channels) could sometimes be an important mechanism of groundwater recharge. Environmental isotope study in Jalore area showed that the shallow groundwaters near the Sukri river course had δ 2 H and δ 18 O are depleted compared to present day precipitation but not as depleted as the present day Himalayan rivers. Carbon-24 values of some of these groundwaters are in the range of 54-58 pMC showing that they possibly represent old river with headwater connection outside the desert. In the Thar, the deep groundwaters which sometimes form the bulk of water supply are generally paleowaters as sown by environmental δ 2 H, δ 18 O, 3 H and 14 C. For example in the Barmer area, deep groundwaters (depth > 150m) have depleted δ 2 H and δ 18 O compared to the shallow groundwaters and present day precipitation. They have negligible 3 H and 14 C model ages ranging from 4000 to 9500 BP. Hence the isotope data of the deep groundwaters indicate they are paleowaters recharged during humid periods in the Holocene. Over-exploitation of deep groundwaters could lead to mixing of shallow and deep groundwaters or influx of waters from adjoining aquifers. In the Bikaner area similar δ 2 H and δ 18 O of the shallow and deep wells and young waters encountered in some of the deep wells indicated mixing between the two aquifers due to heavy exploitation of groundwaters in the area. In a limestone belt of Jodhpur-Nagaur district heavy exploitation of groundwaters is taking place in the southern

  20. Investigating geochemical aspects of managed aquifer recharge by column experiments with alternating desalinated water and groundwater.

    Science.gov (United States)

    Ronen-Eliraz, Gefen; Russak, Amos; Nitzan, Ido; Guttman, Joseph; Kurtzman, Daniel

    2017-01-01

    Managed aquifer recharge (MAR) events are occasionally carried out with surplus desalinated seawater that has been post-treated with CaCO 3 in infiltration ponds overlying the northern part of the Israeli Coastal Aquifer. This water's chemical characteristics differ from those of any other water recharged to the aquifer and of the natural groundwater. As the MAR events are short (hours to weeks), the sediment under the infiltration ponds will intermittently host desalinated and natural groundwater. As part of comprehensive research on the influence of those events, column experiments were designed to simulate the alternation of the two water types: post-treated desalinated seawater (PTDES) and natural groundwater (GW). Each experiment included three stages: (i) saturation with GW; (ii) inflow of PTDES; (iii) inflow of GW. Three runs were conducted, each with different sediments extracted from the field and representing a different layer below the infiltration pond: (i) sand (<1% CaCO 3 ), (ii) sand containing 7% CaCO 3 , and (iii) crushed calcareous sandstone (35% CaCO 3 ). The results from all columns showed enrichment of K + and Mg 2+ (up to 0.4meq/L for 20 pore volumes) when PTDES replaced GW, whereas an opposite trend of Ca 2+ depletion (up to 0.5meq/L) was observed only in the columns that contained a high percentage of CaCO 3 . When GW replaced PTDES, depletion of Mg 2+ and K + was noted. The results indicated that adsorption/desorption of cations are the main processes causing the observed enrichment/depletion. It was concluded that the high concentration of Ca 2+ (relative to the total concentration of cations) and the low concentration of Mg 2+ in the PTDES relative to natural GW are the factors controlling the main sediment-water interaction. The enrichment of PTDES with Mg 2+ may be viewed as an additional post-treatment. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Impact of sub-horizontal discontinuities and vertical heterogeneities on recharge processes in a weathered crystalline aquifer in southern India

    Science.gov (United States)

    Nicolas, Madeleine; Selles, Adrien; Bour, Olivier; Maréchal, Jean-Christophe; Crenner, Marion; Wajiduddin, Mohammed; Ahmed, Shakeel

    2017-04-01

    In the face of increasing demands for irrigated agriculture, many states in India are facing water scarcity issues, leading to severe groundwater depletion. Because perennial water resources in southern India consist mainly of crystalline aquifers, understanding how recharge takes place and the role of preferential flow zones in such heterogeneous media is of prime importance for successful and sustainable aquifer management. Here we investigate how vertical heterogeneities and highly transmissive sub-horizontal discontinuities may control groundwater flows and recharge dynamics. Recharge processes in the vadose zone were examined by analysing the propagation of an infiltration front and mass transfers resulting from the implementation of a managed aquifer recharge (MAR) structure. Said structure was set up in the Experimental Hydrogeological Park in Telangana (Southern India), a well-equipped and continuously monitored site, which is periodically supplied with surface water deviated from the nearby Musi river, downstream of Hyderabad. An initial volume balance equation was applied to quantify the overall inputs from the MAR structure into the groundwater system, which was confirmed using a chloride mass balance approach. To understand how this incoming mass is then distributed within the aquifer, we monitored the evolution of water volumes in the tank, and the resulting lateral propagation front observed in the surrounding borehole network. Borehole logs of temperature and conductivity were regularly performed to identify preferential flow paths. As a result we observed that mass transfers take place in the way of preferential lateral flow through the most transmissive zones of the profile. These include the interface between the lower portion of the upper weathered horizon (the saprolite) and the upper part of the underlying fissured granite, as well as the first flowing fractures. This leads to a rapid lateral transfer of recharge, which allows quick

  2. Areas contributing recharge to production wells and effects of climate change on the groundwater system in the Chipuxet River and Chickasheen Brook Basins, Rhode Island

    Science.gov (United States)

    Friesz, Paul J.; Stone, Janet R.

    2015-01-01

    The Chipuxet River and Chickasheen Brook Basins in southern Rhode Island are an important water resource for public and domestic supply, irrigation, recreation, and aquatic habitat. The U.S. Geological Survey, in cooperation with the Rhode Island Department of Health, began a study in 2012 as part of an effort to protect the source of water to six large-capacity production wells that supply drinking water and to increase understanding of how climate change might affect the water resources in the basins. Soil-water-balance and groundwater-flow models were developed to delineate the areas contributing recharge to the wells and to quantify the hydrologic response to climate change. Surficial deposits of glacial origin ranging from a few feet to more than 200 feet thick overlie bedrock in the 24.4-square mile study area. These deposits comprise a complex and productive aquifer system.

  3. Groundwater use in Pakistan: opportunities and limitations

    International Nuclear Information System (INIS)

    Bhutta, M.N.

    2005-01-01

    Groundwater potential in the Indus Basin is mainly due to recharge from irrigation system, rivers and rainfall. Its quality and quantity varies spatially and temporally. However, the potential is linked with the surface water supplies. Irrigated agriculture is the major user of groundwater. Annual recharge to groundwater in the basin is estimated as 68 MAF. But 50 percent of the area has marginal to hazardous groundwater quality. Existing annual groundwater pumpage is estimated as 45 MAF (55 BCM). More than 13 MAF mainly of groundwater is lost as non-beneficial ET losses. Groundwater contributes 35 percent of total agricultural water requirements in the country. Annual cropping intensities have increased from 70% to 150% due to groundwater use. Increase in crop yield due to groundwater use has been observed 150-200. percent. Total investment on private tube wells has been made more than Rs.25.0 billion. In the areas where farmers are depending more on groundwater. mining of groundwater has been observed. Population pressure, inadequate supply of canal water and development of cheap local tub well technology have encouraged farmers to invest in the groundwater development. Deterioration of groundwater has also been observed due to excessive exploitation. The available information about the private tube wells is insufficient for different areas. Although during the past decade the growth of tube wells was tremendous but was not reflected accordingly in the statistics. Monitoring of groundwater quality is not done systematically and adequately. It is very difficult to manage a resource for which adequate information is not available. The present scenario of groundwater use is not sustainable and therefore certain measures are needed to be taken. It is recommended to. have a systematic monitoring of groundwater. For the sustainable use of groundwater, it is recommended to manage the demand of water i.e. grow more crops with less water. To achieve high productivity of

  4. Isotope study of groundwater in Beishan area, Gansu province

    International Nuclear Information System (INIS)

    Guo Yonghai; Liu Shufen; Yang Tianxiao

    2004-01-01

    Using the isotope techniques, the groundwater origin, evolution and circulation in the potential site of China's high-level waste repository are studied. The results indicate that both shallow groundwaters are and deep groundwaters in the site area are of meteoric origin. The shallow groundwaters are mainly recharged by modern and local precipitation, and the deep groundwaters are originated from regional history period with lower temperature. Through the study we can also understand that the deep underground is a very low-permeability system where the groundwater flow-rates are very low. (author)

  5. Use of nuclear techniques in the study of artificial recharge of groundwater: case of groundwater table in Kairouan plane in Tunisia

    International Nuclear Information System (INIS)

    Benhamouda, M.F.

    1997-01-01

    The groundwater table studied here is located in the plain of Kairouan and it is one of the main underground resources in the Centre of Tunisia. This region is characterized by a semi arid climate with high intensity of rain that causes flooding of Kairouan City. This study has two objectives namely: 1- To develop a technical process of this recharge. The experiment was realized at two sites. In each site were installed 3 neutron probe access tubes to the depth of the level of the ground water table.Successive measurements were taken in each tube in function of depth and time to follow up the hydrodynamics of the recharge of the water table. Neutron and gamma probes were used and compared with respect to measured water content.Each access tube for a fixed time give a water content profile which shows the dynamics of actual recharge and the previous recharge. this technique can help the developer to make decision concerning the recharge parameters and, particularly, the flow rate and the opportunity time to get the best recharge water efficiency. 2- To analyse the concentration of stable and radioactive isotopes in the water of the plain of kairouan. Samples were taken from the shallow and deep water table. The obtained results are helpful to specify the origin of the water. Geochemical analysis were also done to clear the spatial variability of the quality of water. To reach the fore mentioned objectives, a survey of wells using those resources was made. Samples were taken from all surveilled wells in this investigation. water samples were taken from the deep and shallow aquifers and to determine salt concentration as well as stable and radioactive element (O18, H2, C13, C14, H3). The results obtained from chemical analysis showed no clear spatial variability of water quality between the two aquifers. However the isotopic study gave two types of results: First: A significant difference between ages of the water coming from the shallow and the deep ground water

  6. Estimating natural recharge in San Gorgonio Pass watersheds, California, 1913–2012

    Science.gov (United States)

    Hevesi, Joseph A.; Christensen, Allen H.

    2015-12-21

    A daily precipitation-runoff model was developed to estimate spatially and temporally distributed recharge for groundwater basins in the San Gorgonio Pass area, southern California. The recharge estimates are needed to define transient boundary conditions for a groundwater-flow model being developed to evaluate the effects of pumping and climate on the long-term availability of groundwater. The area defined for estimating recharge is referred to as the San Gorgonio Pass watershed model (SGPWM) and includes three watersheds: San Timoteo Creek, Potrero Creek, and San Gorgonio River. The SGPWM was developed by using the U.S. Geological Survey INFILtration version 3.0 (INFILv3) model code used in previous studies of recharge in the southern California region, including the San Gorgonio Pass area. The SGPWM uses a 150-meter gridded discretization of the area of interest in order to account for spatial variability in climate and watershed characteristics. The high degree of spatial variability in climate and watershed characteristics in the San Gorgonio Pass area is caused, in part, by the high relief and rugged topography of the area.

  7. A high resolution global scale groundwater model

    Science.gov (United States)

    de Graaf, Inge; Sutanudjaja, Edwin; van Beek, Rens; Bierkens, Marc

    2014-05-01

    As the world's largest accessible source of freshwater, groundwater plays a vital role in satisfying the basic needs of human society. It serves as a primary source of drinking water and supplies water for agricultural and industrial activities. During times of drought, groundwater storage provides a large natural buffer against water shortage and sustains flows to rivers and wetlands, supporting ecosystem habitats and biodiversity. Yet, the current generation of global scale hydrological models (GHMs) do not include a groundwater flow component, although it is a crucial part of the hydrological cycle. Thus, a realistic physical representation of the groundwater system that allows for the simulation of groundwater head dynamics and lateral flows is essential for GHMs that increasingly run at finer resolution. In this study we present a global groundwater model with a resolution of 5 arc-minutes (approximately 10 km at the equator) using MODFLOW (McDonald and Harbaugh, 1988). With this global groundwater model we eventually intend to simulate the changes in the groundwater system over time that result from variations in recharge and abstraction. Aquifer schematization and properties of this groundwater model were developed from available global lithological maps and datasets (Dürr et al., 2005; Gleeson et al., 2010; Hartmann and Moosdorf, 2013), combined with our estimate of aquifer thickness for sedimentary basins. We forced the groundwater model with the output from the global hydrological model PCR-GLOBWB (van Beek et al., 2011), specifically the net groundwater recharge and average surface water levels derived from routed channel discharge. For the parameterization, we relied entirely on available global datasets and did not calibrate the model so that it can equally be expanded to data poor environments. Based on our sensitivity analysis, in which we run the model with various hydrogeological parameter settings, we observed that most variance in groundwater

  8. Methodology for estimating aquifer recharge direct mfisurado system by the method of ripple of free (WTF) surface Mina Arenal departamento de Rivera

    International Nuclear Information System (INIS)

    Iardino, G.; González, G.; Montaño, J.

    2010-01-01

    The study area is framed in the so-called Crystal Island Rivera region of economic importance to Uruguay considering the gold occurrences . The company Uruguay Mineral Exploration Inc. (UME ) develops prospective exploration projects in the region since 1997 The discovery of a deposit of gold ore results in the opening of the Arenal mine near the town of Minas de Corrales, Department Rivera .Income groundwater to the quarry would affect the progress of the mineral extractive work to control this situation and monitors the evolution of a monitoring program is established with the potentiometric measurement levels and hydrological variables meteorelógicas.The data obtained allowed to estimate the direct recharge of the aquifer system in the area comprising the operational work of the Arenal mine, by applying the method of free surface fluctuation (WTF ) .The WTF method provides an estimate of groundwater recharge by analyzing water level fluctuations in observation wells

  9. Are isolated wetlands groundwater recharge hotspots?

    Science.gov (United States)

    Webb, A.; Wicks, C. M.; Brantley, S. T.; Golladay, S. W.

    2017-12-01

    Geographically isolated wetlands (GIWs) are a common landscape feature in the mantled karst terrain of the Dougherty Plain physiographic district in Southwestern Georgia. These wetlands support a high diversity of obligate/facultative wetland flora and fauna, including several endangered species. While the ecological value of these wetlands is well documented, the hydrologic effects of GIWs on larger watershed processes, such as water storage and aquifer recharge, are less clear. Our project seeks to understand the spatial and temporal variation in recharge across GIWs on this mantled karst landscape. In particular, our first step is to understand the role of isolated wetlands (presumed sinkholes) in delivering water into the underlying aquifer. Our hypothesis is that many GIWs are actually water-filled sinkholes and are locations of focused recharge feeding either the underlying upper Floridan aquifer or the nearby creeks. If we are correct, then these sinkholes should exhibit "drains", i.e., conduits into the limestone bedrock. Thus, the purposes of our initial study are to image the soil-limestone contact (the buried epikarstic surface) and determine if possible subsurface drains exist. Our field work was conducted at the Joseph W Jones Ecological Research Center. During the dry season, we conducted ground penetrating radar (GPR) surveys as grids and lines across a large wetland and across a field with no surface expression of a wetland or sinkhole. We used GPR (200 MHz antenna) with 1-m spacing between antenna and a ping rate of 1 ping per 40 centimeters. Our results show that the epikarstic surface exhibits a drain underneath the wetland (sinkhole) and that no similar feature was seen under the field, even though the survey grid and spacing were similar. As our project progresses, we will survey additional wetlands occurring across varying soil types to determine the spatial distribution between surface wetlands and subsurface drains.

  10. Dissolved Organic Carbon 14C in Southern Nevada Groundwater and Implications for Groundwater Travel Times

    Energy Technology Data Exchange (ETDEWEB)

    Hershey, Ronald L. [Nevada University, Reno, NV (United States). Desert Research Institute; Fereday, Wyall [Nevada University, Reno, NV (United States). Desert Research Institute; Thomas, James M [Nevada University, Reno, NV (United States). Desert Research Institute

    2016-08-01

    Dissolved inorganic carbon (DIC) carbon-14 (14C) ages must be corrected for complex chemical and physical reactions and processes that change the amount of 14C in groundwater as it flows from recharge to downgradient areas. Because of these reactions, DIC 14C can produce unrealistically old ages and long groundwater travel times that may, or may not, agree with travel times estimated by other methods. Dissolved organic carbon (DOC) 14C ages are often younger than DIC 14C ages because there are few chemical reactions or physical processes that change the amount of DOC 14C in groundwater. However, there are several issues that create uncertainty in DOC 14C groundwater ages including limited knowledge of the initial (A0) DOC 14C in groundwater recharge and potential changes in DOC composition as water moves through an aquifer. This study examines these issues by quantifying A0 DOC 14C in recharge areas of southern Nevada groundwater flow systems and by evaluating changes in DOC composition as water flows from recharge areas to downgradient areas. The effect of these processes on DOC 14C groundwater ages is evaluated and DOC and DIC 14C ages are then compared along several southern Nevada groundwater flow paths. Twenty-seven groundwater samples were collected from springs and wells in southern Nevada in upgradient, midgradient, and downgradient locations. DOC 14C for upgradient samples ranged from 96 to 120 percent modern carbon (pmc) with an average of 106 pmc, verifying modern DOC 14C ages in recharge areas, which decreases uncertainty in DOC 14C A0 values, groundwater ages, and travel times. The HPLC spectra of groundwater along a flow path in the Spring Mountains show the same general pattern indicating that the DOC compound composition does not change along this flow path

  11. A high-resolution global-scale groundwater model

    Science.gov (United States)

    de Graaf, I. E. M.; Sutanudjaja, E. H.; van Beek, L. P. H.; Bierkens, M. F. P.

    2015-02-01

    Groundwater is the world's largest accessible source of fresh water. It plays a vital role in satisfying basic needs for drinking water, agriculture and industrial activities. During times of drought groundwater sustains baseflow to rivers and wetlands, thereby supporting ecosystems. Most global-scale hydrological models (GHMs) do not include a groundwater flow component, mainly due to lack of geohydrological data at the global scale. For the simulation of lateral flow and groundwater head dynamics, a realistic physical representation of the groundwater system is needed, especially for GHMs that run at finer resolutions. In this study we present a global-scale groundwater model (run at 6' resolution) using MODFLOW to construct an equilibrium water table at its natural state as the result of long-term climatic forcing. The used aquifer schematization and properties are based on available global data sets of lithology and transmissivities combined with the estimated thickness of an upper, unconfined aquifer. This model is forced with outputs from the land-surface PCRaster Global Water Balance (PCR-GLOBWB) model, specifically net recharge and surface water levels. A sensitivity analysis, in which the model was run with various parameter settings, showed that variation in saturated conductivity has the largest impact on the groundwater levels simulated. Validation with observed groundwater heads showed that groundwater heads are reasonably well simulated for many regions of the world, especially for sediment basins (R2 = 0.95). The simulated regional-scale groundwater patterns and flow paths demonstrate the relevance of lateral groundwater flow in GHMs. Inter-basin groundwater flows can be a significant part of a basin's water budget and help to sustain river baseflows, especially during droughts. Also, water availability of larger aquifer systems can be positively affected by additional recharge from inter-basin groundwater flows.

  12. Quantitative evaluation of flow systems, groundwater recharge and transmissivities using environmental tracers

    Energy Technology Data Exchange (ETDEWEB)

    Adar, E M [Ben-Gurion Univ. of Negev, Sede Boker Campus (Israel). Water Resources Center

    1996-10-01

    This chapter provides an overview of the basic concepts and formulations on the compartmental (mixing-cell) approach for interpretation of isotope and natural tracer data to arrive at quantitative estimates related to groundwater systems. The theoretical basis of the models and the specific solution algorithms used are described. The application of this approach to field cases are described as illustrative examples. Results of sensitivity analyses of the model to different parameters are provided. (author). 81 refs, 13 figs, 8 tabs.

  13. Quantitative evaluation of flow systems, groundwater recharge and transmissivities using environmental tracers

    International Nuclear Information System (INIS)

    Adar, E.M.

    1996-01-01

    This chapter provides an overview of the basic concepts and formulations on the compartmental (mixing-cell) approach for interpretation of isotope and natural tracer data to arrive at quantitative estimates related to groundwater systems. The theoretical basis of the models and the specific solution algorithms used are described. The application of this approach to field cases are described as illustrative examples. Results of sensitivity analyses of the model to different parameters are provided. (author). 81 refs, 13 figs, 8 tabs

  14. Preliminary estimates of spatially distributed net infiltration and recharge for the Death Valley region, Nevada-California

    International Nuclear Information System (INIS)

    Hevesi, J.A.; Flint, A.L.; Flint, L.E.

    2002-01-01

    A three-dimensional ground-water flow model has been developed to evaluate the Death Valley regional flow system, which includes ground water beneath the Nevada Test Site. Estimates of spatially distributed net infiltration and recharge are needed to define upper boundary conditions. This study presents a preliminary application of a conceptual and numerical model of net infiltration. The model was developed in studies at Yucca Mountain, Nevada, which is located in the approximate center of the Death Valley ground-water flow system. The conceptual model describes the effects of precipitation, runoff, evapotranspiration, and redistribution of water in the shallow unsaturated zone on predicted rates of net infiltration; precipitation and soil depth are the two most significant variables. The conceptual model was tested using a preliminary numerical model based on energy- and water-balance calculations. Daily precipitation for 1980 through 1995, averaging 202 millimeters per year over the 39,556 square kilometers area of the ground-water flow model, was input to the numerical model to simulate net infiltration ranging from zero for a soil thickness greater than 6 meters to over 350 millimeters per year for thin soils at high elevations in the Spring Mountains overlying permeable bedrock. Estimated average net infiltration over the entire ground-water flow model domain is 7.8 millimeters per year. To evaluate the application of the net-infiltration model developed on a local scale at Yucca Mountain, to net-infiltration estimates representing the magnitude and distribution of recharge on a regional scale, the net-infiltration results were compared with recharge estimates obtained using empirical methods. Comparison of model results with previous estimates of basinwide recharge suggests that the net-infiltration estimates obtained using this model may overestimate recharge because of uncertainty in modeled precipitation, bedrock permeability, and soil properties for

  15. Integrating urban recharge uncertainty into standard groundwater modeling practice: A case study on water main break predictions for the Barton Springs segment of the Edwards Aquifer, Austin, Texas

    Science.gov (United States)

    Sinner, K.; Teasley, R. L.

    2016-12-01

    Groundwater models serve as integral tools for understanding flow processes and informing stakeholders and policy makers in management decisions. Historically, these models tended towards a deterministic nature, relying on historical data to predict and inform future decisions based on model outputs. This research works towards developing a stochastic method of modeling recharge inputs from pipe main break predictions in an existing groundwater model, which subsequently generates desired outputs incorporating future uncertainty rather than deterministic data. The case study for this research is the Barton Springs segment of the Edwards Aquifer near Austin, Texas. Researchers and water resource professionals have modeled the Edwards Aquifer for decades due to its high water quality, fragile ecosystem, and stakeholder interest. The original case study and model that this research is built upon was developed as a co-design problem with regional stakeholders and the model outcomes are generated specifically for communication with policy makers and managers. Recently, research in the Barton Springs segment demonstrated a significant contribution of urban, or anthropogenic, recharge to the aquifer, particularly during dry period, using deterministic data sets. Due to social and ecological importance of urban water loss to recharge, this study develops an evaluation method to help predicted pipe breaks and their related recharge contribution within the Barton Springs segment of the Edwards Aquifer. To benefit groundwater management decision processes, the performance measures captured in the model results, such as springflow, head levels, storage, and others, were determined by previous work in elicitation of problem framing to determine stakeholder interests and concerns. The results of the previous deterministic model and the stochastic model are compared to determine gains to stakeholder knowledge through the additional modeling

  16. Water circulation within a high-Arctic glaciated valley (Petunia Bay, Central Spitsbergen): Recharge of a glacial river

    Science.gov (United States)

    Marciniak, Marek; Dragon, Krzysztof; Chudziak, Łukasz

    2014-05-01

    This article presents an investigation of the runoff of a glacial river located in the high Arctic region of Spitsbergen. The Ebba River runoff was measured during three melting seasons of 2007, 2008 and 2009. The most important component of the river recharge is the flow of melting water from glaciers (76-82% of total river runoff). However, the other components (surface water and groundwater) also made a significant contribution to the river recharge. The contribution of groundwater flow in total river runoff was estimated by measurements performed in four groups of piezometers located in different parts of the valley. The hydrogeological parameters that characterize shallow aquifer (thickness of the active layer, hydraulic conductivity, groundwater level fluctuations) were recognized by direct field measurements. The groundwater recharging river was the most variable recharge component, and ranged from 1% of the total runoff at the beginning of the melting season to even 27% at the end of summer.

  17. Simulations of Groundwater Flow and Particle Tracking Analysis in the Area Contributing Recharge to a Public-Supply Well near Tampa, Florida, 2002-05

    Science.gov (United States)

    Crandall, Christy A.; Kauffman, Leon J.; Katz, Brian G.; Metz, Patricia A.; McBride, W. Scott; Berndt, Marian P.

    2009-01-01

    groundwater from the surficial aquifer system and lowest (less than the detection level of 0.06 milligram per liter) in the deeper Upper Floridan aquifer. Denitrification occurred near the interface of the surficial aquifer system and the underlying intermediate confining unit, within the intermediate confining unit, and within the Upper Floridan aquifer because of reducing conditions in this part of the flow system. However, simulations indicate that the rapid movement of water from the surficial aquifer system to the selected public-supply well through karst features (sinkholes) and conduit layers that bypass the denitrifying zones (short-circuits), coupled with high pumping rates, allow nitrate to reach the selected public-supply well in concentrations that resemble those of the overlying surficial aquifer system. Water from the surficial aquifer system with elevated concentrations of nitrate and low concentrations of some volatile organic compounds and pesticides is expected to continue moving into the selected public-supply well, because calculated flux-weighted concentrations indicate the proportion of young affected water contributing to the well is likely to remain relatively stable over time. The calculated nitrate concentration in the selected public-supply well indicates a lag of 1 to 10 years between peak concentrations of nonpoint source contaminants in recharge and appearance in the well.

  18. Hydrology and numerical simulation of groundwater flow and streamflow depletion by well withdrawals in the Malad-Lower Bear River Area, Box Elder County, Utah

    Science.gov (United States)

    Stolp, Bernard J.; Brooks, Lynette E.; Solder, John

    2017-03-28

    The Malad-Lower Bear River study area in Box Elder County, Utah, consists of a valley bounded by mountain ranges and is mostly agricultural or undeveloped. The Bear and Malad Rivers enter the study area with a combined average flow of about 1,100,000 acre-feet per year (acre-ft/yr), and this surface water dominates the hydrology. Groundwater occurs in consolidated rock and basin fill. Groundwater recharge occurs from precipitation in the mountains and moves through consolidated rock to the basin fill. Recharge occurs in the valley from irrigation. Groundwater discharge occurs to rivers, springs and diffuse seepage areas, evapotranspiration, field drains, and wells. Groundwater, including springs, is a source for municipal and domestic water supply. Although withdrawal from wells is a small component of the groundwater budget, there is concern that additional groundwater development will reduce the amount of flow in the Malad River. Historical records of surface-water diversions, land use, and groundwater levels indicate relatively stable hydrologic conditions from the 1960s to the 2010s, and that current groundwater development has had little effect on the groundwater system. Average annual recharge to and discharge from the groundwater flow system are estimated to be 164,000 and 228,000 acre-ft/yr, respectively. The imbalance between recharge and discharge represents uncertainties resulting from system complexities, and the possibility of groundwater inflow from surrounding basins.This study reassesses the hydrologic system, refines the groundwater budget, and creates a numerical groundwater flow model that is used to analyze the effects of groundwater withdrawals on surface water. The model uses the detailed catalog of locations and amounts of groundwater recharge and discharge defined during this study. Calibrating the model to adequately simulate recharge, discharge, and groundwater levels results in simulated aquifer properties that can be used to understand

  19. Towards sustainable groundwater management in Karst aquifers in semi-arid environments: Central West Bank, Palestine

    Science.gov (United States)

    Jebreen, H.; Banning, A.; Wohnlich, S.

    2017-12-01

    The Central West Bank (CWB) is characterized by karstified carbonate aquifers in the semiarid climate zone, where groundwater resources are frequently threatened by overexploitation and pollution. Despite often limited system knowledge, quantitative and qualitative factors such as groundwater recharge rate, aquifer parameters, flow and transport dynamics, anthropogenic impacts, and groundwater vulnerability need to be assessed. Therefore, sustainable groundwater use in the CWB is of critical importance. In the present study, we explore the scale of the groundwater problems in CWB as well as the possibility of sustainable management through different scenarios: 1) Managed aquifer recharge using a water balance model, stable isotopes (2H & 18O) and chloride mass balance, 2) Geochemical evolution and renewability of groundwater, and 3) Anthropogenic impacts. A total of 20 spring water samples were collected and analyzed for pH, electrical conductivity, total dissolved solids (TDS), hardness, major-ion chemistry (Cl-, HCO3-, SO42-, Na+, K+, Ca2+ and Mg2+), trace elements (Li, Be, Al, Ba, Tl, Pb, Bi, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Rb, Sr, Mo, Ag and Cd), microbiological data (total and fecal coliforms bacteria), and stable isotopes (2H & 18O). The results show a spatialized recharge rate, which ranges from 111-211 mm/year, representing 17-33 % of the long-term mean annual rainfall. The mean annual actual evapotranspiration was about 19-37 % of precipitation. The chemical composition of groundwater of the study area is strongly influenced by rock-water interaction, dissolution and deposition of carbonate and silicate minerals. Stable isotopes show that precipitation is the source of recharge to the groundwater system. All analyzed spring waters are suitable for irrigation but not for drinking purposes. This studýs results can serve as a basis for decision makers, and will lead to an increased understanding of the sustainable management of the Central West Bank

  20. Water Supply Source Evaluation in Unmanaged Aquifer Recharge Zones: The Mezquital Valley (Mexico Case Study

    Directory of Open Access Journals (Sweden)

    Antonio Hernández-Espriú

    2016-12-01

    Full Text Available The Mezquital Valley (MV hosts the largest unmanaged aquifer recharge scheme in the world. The metropolitan area of Mexico City discharges ~60 m3/s of raw wastewater into the valley, a substantial share of which infiltrates into the regional aquifer. In this work, we aim to develop a comprehensive approach, adapted from oil and gas reservoir modeling frameworks, to assess water supply sources located downgradient from unmanaged aquifer recharge zones. The methodology is demonstrated through its application to the Mezquital Valley region. Geological, geoelectrical, petrophysical and hydraulic information is combined into a 3D subsurface model and used to evaluate downgradient supply sources. Although hydrogeochemical variables are yet to be assessed, outcomes suggest that the newly-found groundwater sources may provide a long-term solution for water supply. Piezometric analyses based on 25-year records suggest that the MV is close to steady-state conditions. Thus, unmanaged recharge seems to have been regulating the groundwater balance for the last decades. The transition from unmanaged to managed recharge is expected to provide benefits to the MV inhabitants. It will also be likely to generate new uncertainties in relation to aquifer dynamics and downgradient systems.

  1. Reconstructing the groundwater flow in the Baltic Basin during the Last glaciation

    Science.gov (United States)

    Saks, T.; Sennikovs, J.; Timuhins, A.; Kalvāns, A.

    2012-04-01

    In last decades it has been discussed that most large ice sheets tend to reside on warm beds even in harsh clima tic conditions and subglacial melting occurs due to geothermal heat flow and deformation heat of the ice flow. However the subglacial groundwater recharge and flow conditions have been addressed in only few studies. The aim of this study is to establish the groundwater flow pattern in the Baltic Basin below the Scandinavian ice sheet during the Late Weichselian glaciation. The calculation results are compared to the known distribution of the groundwater body of the glacial origin found in Cambrian - Vendian (Cm-V) aquifer in the Northern Estonia which is believed to have originated as a result of subglacial meltwater infiltration during the reoccurring glaciations. Steady state regional groundwater flow model of the Baltic Basin was used to simulate the groundwater flow beneath the ice sheet with its geometry adjusted to reflect the subglacial topography. Ice thickness modelling data (Argus&Peltier, 2010) was used for the setup of the boundary conditions: the meltwater pressure at the ice bed was assumed equal to the overlying ice mass. The modelling results suggest two main recharge areas of the Cm-V aquifer system, and reversed groundwater flow that persisted for at least 14 thousand years. Model results show that the groundwater flow velocities in the Cm-V aquifer in the recharge area in N-Estonia beneath the ice sheet exceeded the present velocities by a factor of 10 on average. The calculated meltwater volume recharged into the Cm-V aquifer system during the Late Weichselian corresponds roughly to the estimated, however, considering the fact, that the study area has been glaciated at least 4 times this is an overestimation. The modeling results attest the hypothesis of light dO18 groundwater glacial origin in the Cm-V aquifer system, however the volumes, timing and processes involved in the meltwater intrusion are yet to be explored. This study was

  2. Mapping groundwater renewability using age data in the Baiyang alluvial fan, NW China

    Science.gov (United States)

    Huang, Tianming; Pang, Zhonghe; Li, Jie; Xiang, Yong; Zhao, Zhijiang

    2017-05-01

    Groundwater age has been used to map renewability of water resources within four groups: strong, partial, and rare renewability, and non-renewable. The Baiyang alluvial fan in NW China is a representative area for examining groundwater recharge from river infiltration and for mapping groundwater renewability, and it has been investigated using multiple isotopes and water chemistry. Systematic sampling included 52 samples for 2H and 18O analysis and 32 samples for 3H, 13C and 14C analysis. The δ13C compositions remain nearly constant throughout the basin (median -12.7‰) and indicate that carbonate dissolution does not alter 14C age. The initial 14C activity of 80 pmC, obtained by plotting 3H and 14C activity, was used to correct groundwater 14C age. The results show that areas closer to the river consist of younger groundwater ages; this suggests that river infiltration is the main recharge source to the shallow groundwater system. However, at distances far away from the river, groundwater ages become older, i.e., from modern water (less than 60 year) to pre-modern water (from 60 to 1,000 years) and paleowater (more than 1,000 yeas). The four classifications of groundwater renewability have been associated with different age ranges. The area of shallow groundwater with strong renewability accounts for 74% of the total study area. Because recharge condition (river infiltration) controls overall renewability, a groundwater renewability map is of significant importance to the management of groundwater exploitation of this area as well as other arid groundwater basins.

  3. Sources of high-chloride water and managed aquifer recharge in an alluvial aquifer in California, USA

    Science.gov (United States)

    O'Leary, David R.; Izbicki, John A.; Metzger, Loren F.

    2015-11-01

    As a result of pumping in excess of recharge, water levels in alluvial aquifers within the Eastern San Joaquin Groundwater Subbasin, 130 km east of San Francisco (California, USA), declined below sea level in the early 1950s and have remained so to the present. Chloride concentrations in some wells increased during that time and exceeded the US Environmental Protection Agency's secondary maximum contaminant level of 250 mg/L, resulting in removal of some wells from service. Sources of high-chloride water include irrigation return in 16 % of sampled wells and water from delta sediments and deeper groundwater in 50 % of sampled wells. Chloride concentrations resulting from irrigation return commonly did not exceed 100 mg/L, although nitrate concentrations were as high as 25 mg/L as nitrogen. Chloride concentrations ranged from less than 100-2,050 mg/L in wells affected by water from delta sediments and deeper groundwater. Sequential electromagnetic logs show movement of high-chloride water from delta sediments to pumping wells through permeable interconnected aquifer layers. δD and δ18O data show most groundwater originated as recharge along the front of the Sierra Nevada, but tritium and carbon-14 data suggest recharge rates in this area are low and have decreased over recent geologic time. Managed aquifer recharge at two sites show differences in water-level responses to recharge and in the physical movement of recharged water with depth related to subsurface geology. Well-bore flow logs also show rapid movement of water from recharge sites through permeable interconnected aquifer layers to pumping wells.

  4. Sources of high-chloride water and managed aquifer recharge in an alluvial aquifer in California, USA

    Science.gov (United States)

    O'Leary, David; Izbicki, John A.; Metzger, Loren F.

    2015-01-01

    As a result of pumping in excess of recharge, water levels in alluvial aquifers within the Eastern San Joaquin Groundwater Subbasin, 130 km east of San Francisco (California, USA), declined below sea level in the early 1950s and have remained so to the present. Chloride concentrations in some wells increased during that time and exceeded the US Environmental Protection Agency’s secondary maximum contaminant level of 250 mg/L, resulting in removal of some wells from service. Sources of high-chloride water include irrigation return in 16 % of sampled wells and water from delta sediments and deeper groundwater in 50 % of sampled wells. Chloride concentrations resulting from irrigation return commonly did not exceed 100 mg/L, although nitrate concentrations were as high as 25 mg/L as nitrogen. Chloride concentrations ranged from less than 100–2,050 mg/L in wells affected by water from delta sediments and deeper groundwater. Sequential electromagnetic logs show movement of high-chloride water from delta sediments to pumping wells through permeable interconnected aquifer layers. δD and δ18O data show most groundwater originated as recharge along the front of the Sierra Nevada, but tritium and carbon-14 data suggest recharge rates in this area are low and have decreased over recent geologic time. Managed aquifer recharge at two sites show differences in water-level responses to recharge and in the physical movement of recharged water with depth related to subsurface geology. Well-bore flow logs also show rapid movement of water from recharge sites through permeable interconnected aquifer layers to pumping wells.

  5. A geochemical and hydrological investigation of groundwater recharge in the Roswell basin of New Mexico: summary of results and updated listing of tritium determinations

    International Nuclear Information System (INIS)

    Gross, G.W.; Hoy, R.N.

    1980-04-01

    Different approaches were used to study recharge and flow patterns in the Roswell, New Mexico, artesian basin. Isotope determination for tritium, deuterium, and oxygen-18 were made as a function of time and space. Observation well levels, springflow, and precipitation were analyzed by stochastic/numerical approaches. Also, a hydrogeologic survey was made of representative springs in the recharge zone on the basin western flank. An updated listing of tritium activity in precipitation, springs, surface runoff, and subsurface water from over 120 sampling sites in the basin covers 117 pages of the report. Substantial deep leakage contributions from the basin western flank must be included to account for the basin groundwater budget

  6. Study the mechanisms of recharge of the phreatic aquifers, south east egypt, using environmental isotopes and hydro geochemistry

    International Nuclear Information System (INIS)

    Hassan, T.M.; Awad, M.A.; Hamza, M.S.

    1994-01-01

    The recharge rate is the most critical factor to groundwater resources management especially in semi-arid and arid areas. This paper presents a study on the feasibility of a groundwater development plan for south east egypt area. Environmental stable isotopes (oxygen-18 and deuterium), and hydro geochemistry techniques were used to investigate the recharge sources of groundwater. The examined groundwater wells tap the quaternary, basement and Nubian sandstone aquifers. The isotopic compositions of these groundwater samples indicate that there is a mixing among three different sources of recharge, local precipitation, palaeo water and sea water intrusion along the coastal plain, from the hydrochemical point of view, the predominant water types reflect meteoric, as well as marine waters genesis. The changes in salinity depend upon the dissolution of terrestrial salts, distance from the catchment area and seepage from deep aquifers. 7 figs., 2 tabs

  7. The Ozark Plateaus Regional Aquifer Study—Documentation of a groundwater-flow model constructed to assess water availability in the Ozark Plateaus

    Science.gov (United States)

    Clark, Brian R.; Richards, Joseph M.; Knierim, Katherine J.

    2018-03-30

    Recent short-term drought conditions have emphasized the need to better understand the delicate balance between abundance, sustainability, and scarcity of groundwater in the Ozark Plateaus aquifer system. In 2014, the U.S. Geological Survey began construction of a groundwater-flow model as a tool for the assessment of groundwater availability in the Ozark Plateaus aquifer system. The model was developed to benefit concurrent and future investigations involving groundwater-pumping scenarios, optimization, particle transport, and groundwater-monitoring network analysis.The groundwater model simulates 116 years (1900–2015) of hydrologic conditions and the response of the groundwater system to changes in stress including changes in recharge and groundwater pumping for water supply. Semiseasonal stress periods were simulated from the later part of 1991 to 2015 and represent higher demand and lower recharge in the spring and summer months and lower demand and higher recharge in the fall and winter months. Groundwater pumping increases throughout the simulation period with a maximum rate of about 600 million gallons per day (Mgal/d).The process of matching historical hydrologic data for the Ozark Plateaus aquifer system model was accomplished by a combination of manual changes to parameter values and automated calibration methods. Observation data used in the development and evaluation of the model included 19,045 hydraulic-head observations from 6,683 wells within the model area. Observation data also included stream leakage estimates summed to calculate a net gain or net loss value for approximately 81 named streams.The majority (mean of over 95 percent) of the recharge component is discharged through streams simulated in the model. The total simulated discharge to streams fluctuates seasonally between 7,500 and 17,500 Mgal/d with a mean outflow of 11,500 Mgal/d. Much of the remaining balance between modeled recharge inflows and stream outflows is made up by water

  8. Fluoride in weathered rock aquifers of southern India: Managed Aquifer Recharge for mitigation.

    Science.gov (United States)

    Brindha, K; Jagadeshan, G; Kalpana, L; Elango, L

    2016-05-01

    Climatic condition, geology, and geochemical processes in an area play a major role on groundwater quality. Impact of these on the fluoride content of groundwater was studied in three regions-part of Nalgonda district in Telangana, Pambar River basin, and Vaniyar River basin in Tamil Nadu, southern India, which experience semi-arid climate and are predominantly made of Precambrian rocks. High concentration of fluoride in groundwater above 4 mg/l was recorded. Human exposure dose for fluoride through groundwater was higher in Nalgonda than the other areas. With evaporation and rainfall being one of the major contributors for high fluoride apart from the weathering of fluoride rich minerals from rocks, the effect of increase in groundwater level on fluoride concentration was studied. This study reveals that groundwater in shallow environment of all three regions shows dilution effect due to rainfall recharge. Suitable managed aquifer recharge (MAR) methods can be adopted to dilute the fluoride rich groundwater in such regions which is explained with two case studies. However, in deep groundwater, increase in fluoride concentration with increase in groundwater level due to leaching of fluoride rich salts from the unsaturated zone was observed. Occurrence of fluoride above 1.5 mg/l was more in areas with deeper groundwater environment. Hence, practicing MAR in these regions will increase the fluoride content in groundwater and so physical or chemical treatment has to be adopted. This study brought out the fact that MAR cannot be practiced in all regions for dilution of ions in groundwater and that it is essential to analyze the fluctuation in groundwater level and the fluoride content before suggesting it as a suitable solution. Also, this study emphasizes that long-term monitoring of these factors is an important criterion for choosing the recharge areas.

  9. Boundary delineation for regional groundwater flow through geographic information system (Contract research)

    International Nuclear Information System (INIS)

    Yamakawa, Tadashi; Munakata, Masahiro; Kimura, Hideo; Hyodo, Hiroshi

    2007-03-01

    Radionuclide migration toward the human environment is to be assessed as the part of long-term safety assessments of geologic disposal of radioactive waste. Geologic processes, which include volcanic activity, hydrothermal activity, seismicity and deformation, bring about hydrogeologic changes in the regional groundwater flow system around a repository site. Groundwater flow systems in Japan have been studied in several sites such as Tono mine, Kamaishi mine and Horonobe area, but methodology of studies in these sites does not have fully developed. This study was conducted to develop methodologies of boundary delineation for regional groundwater flow systems. Geographic Information System, GIS, was applied using available topographic, hydrologic and geologic data for an area of interest. Miyakoji in the Abukuma Mountains was selected as the area, for the reason of its simple geologic setting formed by granitic rocks and topographically gentle hills of drainage basin. Data used in this study cover topographic sheets, digital elevation model, satellite imagery, geologic maps, topographic classification maps, soil distribution maps and landuse maps. Through the GIS techniques using these data, thematic maps on topographic features, surface conditions, land coverage, geology and geologic structure and weathered crust were developed, and these thematic maps were further applied to extract four factors affecting the regional groundwater flows: topographic condition, precipitation recharge, fracture characteristics and potential flows. The present study revealed that, taking the potential groundwater flows and characteristics of fractured zones in the area into consideration, the groundwater flow system in Miyakoji drainage basin should be bounded by the Otakine Mountain and the northern part of Tokoha Drainage Basin. The delineated area is larger than understood before. (author)

  10. Radon as a groundwater tracer in Forsmark and Laxemar

    International Nuclear Information System (INIS)

    Grolander, Sara

    2009-10-01

    Radon concentrations were measured in different water types in Forsmark and Laxemar during the site investigation and within this study. From these measurements it can be concluded that large differences between surface water, near surface groundwater and deep groundwater can be found in both Laxemar and Forsmark. The differences in radon concentrations between different water types are used in this study to detect interactions between surface water, near surface water and deep groundwater. From the radon measurements it can also be concluded that radon concentration in deep groundwater varies largely with depth. These variations with depth are probably caused by groundwater flow in conductive fracture zones in the bedrock. The focus of this study has been the radon concentration of near surface groundwater and the interaction between near surface groundwater and deep groundwater. Radon measurements have been done using the RAD-7 radon detector within this study. It could be concluded that RAD-7 is a good technique for radon measurements and also easy to use in field. The radon concentrations measured in near surface groundwater in Laxemar within this study were low and homogenous. The variation in radon concentration has been analyses and compared to other parameters. Since the hypothesis of this study has been that there are differences in radon concentrations between recharging and discharging groundwater, the most important parameter to consider is the recharge/discharge field classification of the wells. No correlation between the recharge/discharge classifications of wells and the radon concentrations were found. The lack of correlation between groundwater flow patterns and radon concentration means that it is not possible to detect flow patterns in near surface groundwater using radon as a tracer in the Laxemar area. The lack of correlation can be caused by the fact that there are just a few wells located in areas classified as recharge area. It can also be

  11. Spatial and temporal constraints on regional-scale groundwater flow in the Pampa del Tamarugal Basin, Atacama Desert, Chile

    Science.gov (United States)

    Jayne, Richard S.; Pollyea, Ryan M.; Dodd, Justin P.; Olson, Elizabeth J.; Swanson, Susan K.

    2016-12-01

    Aquifers within the Pampa del Tamarugal Basin (Atacama Desert, northern Chile) are the sole source of water for the coastal city of Iquique and the economically important mining industry. Despite this, the regional groundwater system remains poorly understood. Although it is widely accepted that aquifer recharge originates as precipitation in the Altiplano and Andean Cordillera to the east, there remains debate on whether recharge is driven primarily by near-surface groundwater flow in response to periodic flood events or by basal groundwater flux through deep-seated basin fractures. In addressing this debate, the present study quantifies spatial and temporal variability in regional-scale groundwater flow paths at 20.5°S latitude by combining a two-dimensional model of groundwater and heat flow with field observations and δ18O isotope values in surface water and groundwater. Results suggest that both previously proposed aquifer recharge mechanisms are likely influencing aquifers within the Pampa del Tamarugal Basin; however, each mechanism is operating on different spatial and temporal scales. Storm-driven flood events in the Altiplano readily transmit groundwater to the eastern Pampa del Tamarugal Basin through near-surface groundwater flow on short time scales, e.g., 100-101 years, but these effects are likely isolated to aquifers in the eastern third of the basin. In addition, this study illustrates a physical mechanism for groundwater originating in the eastern highlands to recharge aquifers and salars in the western Pampa del Tamarugal Basin over timescales of 104-105 years.

  12. Review: Recharge rates and chemistry beneath playas of the High Plains aquifer, USA

    Science.gov (United States)

    Gurdak, Jason J.; Roe, Cassia D.

    2010-12-01

    Playas are ephemeral, closed-basin wetlands that are hypothesized as an important source of recharge to the High Plains aquifer in central USA. The ephemeral nature of playas, low regional recharge rates, and a strong reliance on groundwater from the High Plains aquifer has prompted many questions regarding the contribution and quality of recharge from playas to the High Plains aquifer. As a result, there has been considerable scientific debate about the potential for water to infiltrate the relatively impermeable playa floors, travel through the unsaturated zone sediments that are tens of meters thick, and subsequently recharge the High Plains aquifer. This critical review examines previously published studies on the processes that control recharge rates and chemistry beneath playas. Reported recharge rates beneath playas range from less than 1.0 to more than 500 mm/yr and are generally 1-2 orders of magnitude higher than recharge rates beneath interplaya settings. Most studies support the conceptual model that playas are important zones of recharge to the High Plains aquifer and are not strictly evaporative pans. The major findings of this review provide science-based implications for management of playas and groundwater resources of the High Plains aquifer and directions for future research.

  13. Use of regional climate models data for groundwater recharge modelling in Baltic artesian basin

    Science.gov (United States)

    Timuhins, A.; Klints, I.; Sennikovs, J.; Virbulis, J.

    2012-04-01

    Baltic artesian basin (BAB) covers about 480000 square kilometres. BAB includes territory of Latvia, Lithuania, Estonia, parts of Poland, Russia, Belarus and Baltic Sea. The closed hydrogeological mathematical model for the BAB is developed in University of Latvia and reference calculations made in steady state mode. No-flow boundary condition is applied on the bottom and side boundaries of BAB. Hydraulic head is fixed on the seabed and largest lakes, and along the main river lines. Main water supply wells also are presented in the model as a pointwise water extraction. Precipitation is the main source of the groundwater recharge in the BAB region. Infiltration parameterization is responsible for this water source in BAB model. During the early stage of calibration of BAB hydrogeological model an automatic calibration for the hydraulic conductivities of permeable layers and single infiltration rate was attempted. Performing BAB model calibration it was noted that the differences of calculated and observed hydraulic heads (used for calculating the calibration penalty function) can be reduced by introducing a spatially distributed infiltration model. The aim of the present study is improving of the infiltration model, as well as preserving a short computation time (several minutes) for the piezometric head. Direct solution of improvement of the infiltration would be a usage of the advanced hydrological models. However, an accurate hydrological model requires a lot of computational power. It should couple meteorological and hydrological parameters and requires additional calibration. The regional climate model (KNMI-RACMO2 25 km resolution) results from ENSEMBLES project are used for the spatially distributed infiltration field calculation. The infiltration field is constructed as weighted difference of 30 year averaged precipitation and evaporation fields. The weight value is calibrated and a considerable decrease of the value of penalty function of the groundwater

  14. A geochemical and isotopic approach to recharge evaluation in semi-arid zones. Past and present

    International Nuclear Information System (INIS)

    Edmunds, W.M.; Walton, N.R.G.

    1980-01-01

    The magnitude of any recharge to aquifers in semi-arid and arid zones is the principal uncertainty in estimating a water balance. Recent studies in Cyprus and Libyan Arab Jamahiriya are currently being used to demonstrate the application of geochemical and isotopic techniques, to the determination of both current and palaeo-recharge. In Cyprus, solute profiles of the unsaturated zone have been interpreted to provide estimates of the direct recharge component using a steady-state, mass-balance approach; results from the chloride profiles compare well with recharge estimates using tritium. In addition, it is found that some solute peaks, notably for specific electrical conductance, give a reasonably accurate record of the rainfall history during the period 1950-1975. The solute profile method is relatively unsophisticated and could be more widely applied to recharge estimation in other semi-arid areas of the world. In Libya, a clear distinction can be made using the combined isotopic, hydrological and geochemical results between regional groundwaters recharged to the upper, unconfined aquifer of the Sirte Basin before 13,000 years BP and younger waters recharged locally during the period 5000-7800 years BP. A well-defined fresh-water channel, superimposed upon the regional water quality pattern, can be traced within the aquifer for some 130 km and represents direct evidence of recharge during the Holocene. Some shallow groundwaters of similar composition to the fresh-water channel are also considered to represent recent, if intermittent, recharge which took place during historical times. It is concluded that geochemical and isotopic studies of both the unsaturated zone and of shallow groundwaters in semi-arid regions, can be used to determine not only the present-day direct recharge component, but also a recharge chronology of immediate historic times, which may be important in the estimation of long-term water resources. (author)

  15. Steady-state groundwater recharge in trapezoidal-shaped aquifers: A semi-analytical approach based on variational calculus

    Science.gov (United States)

    Mahdavi, Ali; Seyyedian, Hamid

    2014-05-01

    This study presents a semi-analytical solution for steady groundwater flow in trapezoidal-shaped aquifers in response to an areal diffusive recharge. The aquifer is homogeneous, anisotropic and interacts with four surrounding streams of constant-head. Flow field in this laterally bounded aquifer-system is efficiently constructed by means of variational calculus. This is accomplished by minimizing a properly defined penalty function for the associated boundary value problem. Simple yet demonstrative scenarios are defined to investigate anisotropy effects on the water table variation. Qualitative examination of the resulting equipotential contour maps and velocity vector field illustrates the validity of the method, especially in the vicinity of boundary lines. Extension to the case of triangular-shaped aquifer with or without an impervious boundary line is also demonstrated through a hypothetical example problem. The present solution benefits from an extremely simple mathematical expression and exhibits strictly close agreement with the numerical results obtained from Modflow. Overall, the solution may be used to conduct sensitivity analysis on various hydrogeological parameters that affect water table variation in aquifers defined in trapezoidal or triangular-shaped domains.

  16. Assessment of groundwater response to droughts in a complex runoff-dominated watershed by using an integrated hydrologic model

    Science.gov (United States)

    Woolfenden, L. R.; Hevesi, J. A.; Nishikawa, T.

    2014-12-01

    Groundwater is an important component of the water supply, especially during droughts, within the Santa Rosa Plain watershed (SRPW), California, USA. The SRPW is 680 km2 and includes a network of natural and engineered stream channels. Streamflow is strongly seasonal, with high winter flows, predominantly intermittent summer flows, and comparatively rapid response time to larger storms. Groundwater flow is influenced primarily by complex geology, spatial and temporal variation in recharge, and pumping for urban, agricultural, and rural demands. Results from an integrated hydrologic model (GSFLOW) for the SRPW were analyzed to assess the effect of droughts on groundwater resources during water years 1976-2010. Model results indicate that, in general, below-average precipitation during historical drought periods reduced groundwater recharge (focused within stream channels and diffuse outside of channels on alluvial plains), groundwater evapotranspiration (ET), and groundwater discharge to streams (baseflow). In addition, recharge during wet periods was not sufficient to replenish groundwater-storage losses caused by drought and groundwater pumping, resulting in an overall 150 gigaliter loss in groundwater storage for water years 1976-2010. During drought periods, lower groundwater levels from reduced recharge broadly increased the number and length of losing-stream reaches, and seepage losses in streams became a higher percentage of recharge relative to the diffuse recharge outside of stream channels (for example, seepage losses in streams were 36% of recharge in 2006 and 57% at the end of the 2007-09 drought). Reductions in groundwater storage during drought periods resulted in decreased groundwater ET (loss of riparian habitat) and baseflow, especially during the warmer and dryer months (May through September) when groundwater is the dominant component of streamflow.

  17. Screening of sustainable groundwater sources for integration into a regional drought-prone water supply system

    Directory of Open Access Journals (Sweden)

    H. Lucas

    2009-07-01

    Full Text Available This paper reports on the qualitative and quantitative screening of groundwater sources for integration into the public water supply system of the Algarve, Portugal. The results are employed in a decision support system currently under development for an integrated water resources management scheme in the region. Such a scheme is crucial for several reasons, including the extreme seasonal and annual variations in rainfall, the effect of climate change on more frequent and long-lasting droughts, the continuously increasing water demand and the high risk of a single-source water supply policy. The latter was revealed during the severe drought of 2004 and 2005, when surface reservoirs were depleted and the regional water demand could not be met, despite the drilling of emergency wells.

    For screening and selection, quantitative criteria are based on aquifer properties and well yields, whereas qualitative criteria are defined by water quality indices. These reflect the well's degree of violation of drinking water standards for different sets of variables, including toxicity parameters, nitrate and chloride, iron and manganese and microbiological parameters. Results indicate the current availability of at least 1100 l s−1 of high quality groundwater (55% of the regional demand, requiring only disinfection (900 l s−1 or basic treatment, prior to human consumption. These groundwater withdrawals are sustainable when compared to mean annual recharge, considering that at least 40% is preserved for ecological demands. A more accurate and comprehensive analysis of sustainability is performed with the help of steady-state and transient groundwater flow simulations, which account for aquifer geometry, boundary conditions, recharge and discharge rates, pumping activity and seasonality. They permit an advanced analysis of present and future scenarios and show that increasing water demands and decreasing rainfall will make

  18. Groundwater flow system under a rapidly urbanizing coastal city as determined by hydrogeochemistry

    Science.gov (United States)

    Kagabu, Makoto; Shimada, Jun; Delinom, Robert; Tsujimura, Maki; Taniguchi, Makoto

    2011-01-01

    In the Jakarta area (Indonesia), excessive groundwater pumping due to the rapidly increasing population has caused groundwater-related problems such as brackish water contamination in coastal areas and land subsidence. In this study, we adopted multiple hydrogeochemical techniques to demonstrate the groundwater flow system in the Jakarta area. Although almost all groundwater existing in the Jakarta basin is recharged at similar elevations, the water quality and residence time demonstrates a clear difference between the shallow and deep aquifers. Due to the rapid decrease in the groundwater potential in urban areas, we found that the seawater intrusion and the shallow and deep groundwaters are mixing, a conclusion confirmed by major ions, Br -:Cl - ratios, and chlorofluorocarbon (CFC)-12 analysis. Spring water and groundwater samples collected from the southern mountainside area show younger age characteristics with high concentrations of 14C and Ca-HCO 3 type water chemistry. We estimated the residence times of these groundwaters within 45 years under piston flow conditions by tritium analysis. Also, these groundwater ages can be limited to 20-30 years with piston flow evaluated by CFCs. Moreover, due to the magnitude of the CFC-12 concentration, we can use a pseudo age indicator in this field study, because we found a positive correlation between the major type of water chemistry and the CFC-12 concentration.

  19. Groundwater-flow model of the northern High Plains aquifer in Colorado, Kansas, Nebraska, South Dakota, and Wyoming

    Science.gov (United States)

    Peterson, Steven M.; Flynn, Amanda T.; Traylor, Jonathan P.

    2016-12-13

    estimation suite of software with Tikhonov regularization. Calibration targets for the groundwater model included 343,067 groundwater levels measured in wells and 10,820 estimated monthly stream base flows at streamgages. A total of 1,312 parameters were adjusted during calibration to improve the match between calibration targets and simulated equivalents. Comparison of calibration targets to simulated equivalents indicated that, at the regional scale, the model correctly reproduced groundwater levels and stream base flows for 1940–2009. This comparison indicates that the model can be used to examine the likely response of the aquifer system to potential future stresses.Mean calibrated recharge for 1940–49 and 2000–2009 was smaller than that estimated with the soil-water-balance model. This indicated that although the general spatial patterns of recharge estimated with the soil-water-balance model were approximately correct at the regional scale of the Northern High Plains aquifer, the soil-water-balance model had overestimated recharge, and adjustments were needed to decrease recharge to improve the match of the groundwater model to calibration targets. The largest components of the simulated groundwater budgets were recharge from precipitation, recharge from canal seepage, outflows to evapotranspiration, and outflows to stream base flow. Simulated outflows to irrigation wells increased from 7 percent of total outflows in 1940–49 to 38 percent of 1970–79 total outflows and 49 percent of 2000–2009 total outflows.

  20. Hanford statewide groundwater flow and transport model calibration report

    International Nuclear Information System (INIS)

    Law, A.; Panday, S.; Denslow, C.; Fecht, K.; Knepp, A.

    1996-04-01

    This report presents the results of the development and calibration of a three-dimensional, finite element model (VAM3DCG) for the unconfined groundwater flow system at the Hanford Site. This flow system is the largest radioactively contaminated groundwater system in the United States. Eleven groundwater plumes have been identified containing organics, inorganics, and radionuclides. Because groundwater from the unconfined groundwater system flows into the Columbia River, the development of a groundwater flow model is essential to the long-term management of these plumes. Cost effective decision making requires the capability to predict the effectiveness of various remediation approaches. Some of the alternatives available to remediate groundwater include: pumping contaminated water from the ground for treatment with reinjection or to other disposal facilities; containment of plumes by means of impermeable walls, physical barriers, and hydraulic control measures; and, in some cases, management of groundwater via planned recharge and withdrawals. Implementation of these methods requires a knowledge of the groundwater flow system and how it responds to remedial actions

  1. Single event time series analysis in a binary karst catchment evaluated using a groundwater model (Lurbach system, Austria).

    Science.gov (United States)

    Mayaud, C; Wagner, T; Benischke, R; Birk, S

    2014-04-16

    The Lurbach karst system (Styria, Austria) is drained by two major springs and replenished by both autogenic recharge from the karst massif itself and a sinking stream that originates in low permeable schists (allogenic recharge). Detailed data from two events recorded during a tracer experiment in 2008 demonstrate that an overflow from one of the sub-catchments to the other is activated if the discharge of the main spring exceeds a certain threshold. Time series analysis (autocorrelation and cross-correlation) was applied to examine to what extent the various available methods support the identification of the transient inter-catchment flow observed in this binary karst system. As inter-catchment flow is found to be intermittent, the evaluation was focused on single events. In order to support the interpretation of the results from the time series analysis a simplified groundwater flow model was built using MODFLOW. The groundwater model is based on the current conceptual understanding of the karst system and represents a synthetic karst aquifer for which the same methods were applied. Using the wetting capability package of MODFLOW, the model simulated an overflow similar to what has been observed during the tracer experiment. Various intensities of allogenic recharge were employed to generate synthetic discharge data for the time series analysis. In addition, geometric and hydraulic properties of the karst system were varied in several model scenarios. This approach helps to identify effects of allogenic recharge and aquifer properties in the results from the time series analysis. Comparing the results from the time series analysis of the observed data with those of the synthetic data a good agreement was found. For instance, the cross-correlograms show similar patterns with respect to time lags and maximum cross-correlation coefficients if appropriate hydraulic parameters are assigned to the groundwater model. The comparable behaviors of the real and the

  2. The Impact of Climate Change on Groundwater Resources and Groundwater Quality in the Patcham Catchment, England.

    Science.gov (United States)

    Phillips, R. J.; Smith, M.; Pope, D. J.; Gumm, L.

    2012-04-01

    The CLIMAWAT project is an EU-Regional Development Fund Interreg IV funded research programme to study the impacts of climate change on groundwater resources and groundwater quality from the Chalk aquifer of SE England. The use of partially treated wastewater for artificial recharge will also be extensively studied in both the field and laboratory. The Chalk is a major aquifer and regionally supplies 70% of potable water supplies. The long term sustainable use of this resource is of paramount importance and the outcomes of this project will better inform and enhance long term management strategies for this. Project partners include water companies, regulatory bodies and industry consultancies. The four main objectives of the CLIMAWAT project are: i) better improve the prediction of the impact of climate change on this groundwater resource; ii) better understand and quantify how recharge mechanisms will vary due to the uncertainty associated with climate change; iii) better understand the storage mechanisms and fate of contaminants (e.g. nitrates and pesticides) in this aquifer and iv) investigate the impact of using partially treated wastewater for artificial recharge. An extensive field monitoring and data collection programme is underway in the Patcham Catchment (SE of England). Simultaneous monitoring of climatic, unsaturated zone potentiometric, groundwater level and chemistry data will allow for a better understanding of how changes in recharge patterns will effect groundwater quality and quantity. Isoptopic analysis of sampled groundwaters has allowed for interpretations and a better understanding of the storage and movement of water through this aquifer. The laboratory experimental programme is also underway and the results from this will compliment the field based studies to further enhance the understanding of contaminant behaviour in the both unsaturated and saturated zones. Core experiments are being used to investigate how nutrient and other

  3. Hydrochemical and Isotopic Investigation of Groundwater in the Hammamet-Nabeul Aquifer System, North-Eastern Tunisia

    Energy Technology Data Exchange (ETDEWEB)

    Ben Moussa, A.; Zouari, K. [Laboratory of Radio-Analysis and Environment, ENIS, Sfax (Tunisia); Kurttas, T. [Isotope Hydrology Section, International Atomic Energy Agency, Vienna (Austria)

    2013-07-15

    The combination of major element geochemistry, stable ({delta}{sup 18}O, {delta}{sup 2}H) and radioactive ({sup 3}H, {sup 14}C) isotopes has provided a comprehensive understanding of the natural and anthropogenic processes that control groundwater mineralization as well as the sources of different groundwater bodies within the Hammamet-Nabeul unconfined aquifer (Cap Bon peninsula, northeastern Tunisia). The geochemical examination shows the dominance of Na-Cl and Ca-SO{sub 4} water types resulting from the dissolution of halite and gypsum, the dedolomitization and the cation exchange process. Additionally, the return flow process in relation with the long term flood irrigation practice contributes to the mineralization by producing high amounts of nitrate. The stable isotope signatures reveal the existence of two groundwater groups. The non-evaporated groundwaters with relatively depleted contents, reflecting recharge at higher altitudes; and evaporated groundwaters with enriched contents highlighting the influence of return flow of irrigation waters. Tritium contents in these two groups provide evidence of the presence of pre- 1950 and post-1960 recharge periods. Carbon-14 activities in shallow wells, in spite of their contamination by organic {sup 14}C, confirm the recent origin of the groundwaters in the study area. (author)

  4. Integrated assessment of the impact of climate and land use changes on groundwater quantity and quality in the Mancha Oriental system (Spain)

    Science.gov (United States)

    Pulido-Velazquez, M.; Peña-Haro, S.; García-Prats, A.; Mocholi-Almudever, A. F.; Henriquez-Dole, L.; Macian-Sorribes, H.; Lopez-Nicolas, A.

    2015-04-01

    Climate and land use change (global change) impacts on groundwater systems cannot be studied in isolation. Land use and land cover (LULC) changes have a great impact on the water cycle and contaminant production and transport. Groundwater flow and storage are changing in response not only to climatic changes but also to human impacts on land uses and demands, which will alter the hydrologic cycle and subsequently impact the quantity and quality of regional water systems. Predicting groundwater recharge and discharge conditions under future climate and land use changes is essential for integrated water management and adaptation. In the Mancha Oriental system (MOS), one of the largest groundwater bodies in Spain, the transformation from dry to irrigated lands during the last decades has led to a significant drop of the groundwater table, with the consequent effect on stream-aquifer interaction in the connected Jucar River. Understanding the spatial and temporal distribution of water quantity and water quality is essential for a proper management of the system. On the one hand, streamflow depletion is compromising the dependent ecosystems and the supply to the downstream demands, provoking a complex management issue. On the other hand, the intense use of fertilizer in agriculture is leading to locally high groundwater nitrate concentrations. In this paper we analyze the potential impacts of climate and land use change in the system by using an integrated modeling framework that consists in sequentially coupling a watershed agriculturally based hydrological model (Soil and Water Assessment Tool, SWAT) with a groundwater flow model developed in MODFLOW, and with a nitrate mass-transport model in MT3DMS. SWAT model outputs (mainly groundwater recharge and pumping, considering new irrigation needs under changing evapotranspiration (ET) and precipitation) are used as MODFLOW inputs to simulate changes in groundwater flow and storage and impacts on stream

  5. River-groundwater connectivity in a karst system, Wellington, New South Wales, Australia

    Science.gov (United States)

    Keshavarzi, Mohammadreza; Baker, Andy; Kelly, Bryce F. J.; Andersen, Martin S.

    2017-03-01

    The characterization of river-aquifer connectivity in karst environments is difficult due to the presence of conduits and caves. This work demonstrates how geophysical imaging combined with hydrogeological data can improve the conceptualization of surface-water and groundwater interactions in karst terrains. The objective of this study is to understand the association between the Bell River and karst-alluvial aquifer at Wellington, Australia. River and groundwater levels were continuously monitored, and electrical resistivity imaging and water quality surveys conducted. Two-dimensional resistivity imaging mapped the transition between the alluvium and karst. This is important for highlighting the proximity of the saturated alluvial sediments to the water-filled caves and conduits. In the unsaturated zone the resistivity imaging differentiated between air- and sediment-filled karst features, and in the saturated zone it mapped the location of possible water- and sediment-filled caves. Groundwater levels are dynamic and respond quickly to changes in the river stage, implying that there is a strong hydraulic connection, and that the river is losing and recharging the adjacent aquifer. Groundwater extractions (1,370 ML, megalitres, annually) from the alluvial aquifer can cause the groundwater level to fall by as much as 1.5 m in a year. However, when the Bell River flows after significant rainfall in the upper catchment, river-leakage rapidly recharges the alluvial and karst aquifers. This work demonstrates that in complex hydrogeological settings, the combined use of geophysical imaging, hydrograph analysis and geochemical measurements provide insights on the local karst hydrology and groundwater processes, which will enable better water-resource and karst management.

  6. Hydrochemical and isotopic characteristics of groundwater in the northeastern Tennger Desert, northern China

    Science.gov (United States)

    Wang, Liheng; Dong, Yanhui; Xu, Zhifang; Qiao, Xiaojuan

    2017-12-01

    Groundwater is typically the only water source in arid regions, and its circulation processes should be better understood for rational resource exploitation. Stable isotopes and major ions were investigated in the northeastern Tengger Desert, northern China, to gain insights into groundwater recharge and evolution. In the northern mountains, Quaternary unconsolidated sediments, exposed only in valleys between hills, form the main aquifer, which is mainly made of aeolian sand and gravel. Most of the mountain groundwater samples plot along the local meteoric water line (LMWL), with a more depleted signature compared to summer precipitation, suggesting that mountain groundwater was recharged by local precipitation during winter. Most of the groundwater was fresh, with total dissolved solids less than 1 g/L; dominant ions are Na+, SO4 2- and Cl-, and all mineral saturation indices are less than zero. Evaporation, dissolution and cation exchange are the major hydrogeochemical processes. In the southern plains, however, the main aquifers are sandstone. The linear regression line of δD and δ 18O of groundwater parallels the LMWL but the intercept is lower, indicating that groundwater in the plains has been recharged by ancient precipitation rather than modern. Both calcite and dolomite phases in the plains groundwater are close to saturation, while gypsum and halite can still be dissolved into the groundwater. Different recharge mechanisms occur in the northern mountains and the southern plains, and the hydraulic connection between them is weak. Because of the limited recharge, groundwater exploitation should be limited as much as possible.

  7. Environmental isotopes, chemical composition and groundwater recharge in ataqa-north galala region, Egypt

    International Nuclear Information System (INIS)

    Shohaib, R.EL-SH.; Nada, A.; Safie El-Din, A.

    1991-01-01

    Groundwater samples collected from a number of localities in ataqa-north galala region were subjected to various chemical and isotopic analyses. The seasonal fluctuations in hydrochemical composition reveal that the marin Mg Cl 2 type is dominant in the aquifer through-out the year. The Ca Cl 2 water type of marine origin appears in January in wells W 3 and W 7 which lie close to sukhna fault. Recharge to the aquifer is reflected by fluctuation in the water level and fluctuations of the hydrochemical composition of the water. The results of the isotopic content of the water samples indicate that the connate marine water has been subjected to dilution and mixing by the meteoric water invasion since the pliestocene pluvial period (paleowater) and recent meteoric water precipitation. The bulk of the stored water ( about 80%) is paleowater and the recent water (20%) are percolate ones derived from the rain-fall at high latitudes.4 fig. 1 tab

  8. Evaluation of remotely sensed data for estimating recharge to an outcrop zone of the Guarani Aquifer System (South America)

    Science.gov (United States)

    Lucas, Murilo; Oliveira, Paulo T. S.; Melo, Davi C. D.; Wendland, Edson

    2015-08-01

    The Guarani Aquifer System (GAS) is the largest transboundary groundwater reservoir in South America, yet recharge in the GAS outcrop zones is one of the least known hydrological variables. The objective of this study was to assess the suitability of using remote sensing data in the water-budget equation for estimating recharge inter-annual patterns in a representative GAS outcropping area. Data were obtained from remotely sensed estimates of precipitation ( P) and evapotranspiration (ET) using TRMM 3B42 V7 and MOD16, respectively, in the Onça Creek watershed in Brazil over the 2004-2012 period. This is an upland flat watershed (slope steepness <1 %) dominated by sandy soils and representative of the GAS outcrop zones. The remote sensing approach was compared to the water-table fluctuation (WTF) method and another water-budget equation using ground-based measurements. On a monthly basis, the TRMM P estimate showed significant agreement with the ground-based P data ( r = 0.93 and RMSE = 41 mm). Mean(±SD) satellite-based recharge ( R sat) was 537(±224) mm year-1. Mean ground-based recharge using the water-budget ( R gr) and the WTF ( R wtf) methods were 469 mm year-1 and 311(±75) mm year-1, respectively. Results show that 440 mm year-1 is a mean (between R sat, R gr and R wtf) recharge for the study area over the 2004-2012 period. The latter mean recharge estimate is about 29 % of the mean historical P (1,514 mm year-1). These results are useful for future studies on assessing recharge in the GAS outcrop zones where data are scarce or nonexistent.

  9. Radon as a groundwater tracer in Forsmark and Laxemar

    Energy Technology Data Exchange (ETDEWEB)

    Grolander, Sara

    2009-10-15

    Radon concentrations were measured in different water types in Forsmark and Laxemar during the site investigation and within this study. From these measurements it can be concluded that large differences between surface water, near surface groundwater and deep groundwater can be found in both Laxemar and Forsmark. The differences in radon concentrations between different water types are used in this study to detect interactions between surface water, near surface water and deep groundwater. From the radon measurements it can also be concluded that radon concentration in deep groundwater varies largely with depth. These variations with depth are probably caused by groundwater flow in conductive fracture zones in the bedrock. The focus of this study has been the radon concentration of near surface groundwater and the interaction between near surface groundwater and deep groundwater. Radon measurements have been done using the RAD-7 radon detector within this study. It could be concluded that RAD-7 is a good technique for radon measurements and also easy to use in field. The radon concentrations measured in near surface groundwater in Laxemar within this study were low and homogenous. The variation in radon concentration has been analyses and compared to other parameters. Since the hypothesis of this study has been that there are differences in radon concentrations between recharging and discharging groundwater, the most important parameter to consider is the recharge/discharge field classification of the wells. No correlation between the recharge/discharge classifications of wells and the radon concentrations were found. The lack of correlation between groundwater flow patterns and radon concentration means that it is not possible to detect flow patterns in near surface groundwater using radon as a tracer in the Laxemar area. The lack of correlation can be caused by the fact that there are just a few wells located in areas classified as recharge area. It can also be

  10. Numerical simulation of the groundwater-flow system of the Kitsap Peninsula, west-central Washington

    Science.gov (United States)

    Frans, Lonna M.; Olsen, Theresa D.

    2016-05-05

    ,905 acre-ft/yr (7 percent of total simulated inflow). Simulated outflow from the model primarily was through discharge to streams, lakes, springs, seeps, and Puget Sound (594,595 acre-ft/yr; 95 percent of total simulated outflow excluding changes in storage) and through withdrawals from wells (30,761 acre-ft/yr; 5 percent of total simulated outflow excluding changes in storage).Six scenarios were formulated with input from project stakeholders and were simulated using the calibrated model to provide representative examples of how the model could be used to evaluate the effects on water levels and stream baseflows of potential changes in groundwater withdrawals, in consumptive use, and in recharge. These included simulations of a steady-state system, no-pumping and return flows, 15-percent increase in current withdrawals in all wells, 80-percent decrease in outdoor water to simulate effects of conservation efforts, 15-percent decrease in recharge from precipitation to simulate a drought, and particle tracking to determine flow paths.Changes in water-level altitudes and baseflow amounts vary depending on the stress applied to the system in these various scenarios. Reducing recharge by 15 percent between 2005 and 2012 had the largest effect, with water-level altitudes declining throughout the model domain and baseflow amounts decreasing by as much as 18 percent compared to baseline conditions. Changes in pumping volumes had a smaller effect on the model. Removing all pumping and resulting return flows caused increased water-level altitudes in many areas and increased baseflow amounts of between 1 and 3 percent.

  11. Occurrence and distribution of organophosphorus flame retardants and plasticizers in anthropogenically affected groundwater.

    Science.gov (United States)

    Regnery, J; Püttmann, W; Merz, C; Berthold, G

    2011-02-01

    Occurrence and distribution of chlorinated and non-chlorinated organophosphates in 72 groundwater samples from Germany under different recharge/infiltration conditions were investigated. Tris(2-chloro-1-methylethyl) phosphate (TCPP) and tris(2-chloroethyl) phosphate (TCEP) were the most frequently detected organophosphates in groundwater samples. Highest individual organophosphate concentrations (>0.1 µg L(-1)) were determined in groundwater polluted by infiltrating leachate and groundwater recharged via riverbank filtration of organophosphate-loaded recipients. In samples from springs and deep groundwater monitoring wells that are not affected by surface waters, organophosphate concentrations were mostly below the limit of detection. The occurrence (3-9 ng L(-1)) of TCPP and TCEP in samples from aquifers with groundwater ages between 20 and 45 years indicates the persistence of both compounds within the aquifer. At urban sites organophosphate-loaded precipitation, surface runoff, and leakage of wastewater influenced groundwater quality. For rural sites, where groundwater recharge is only influenced by precipitation, organophosphates were very rarely detectable in groundwater.

  12. Estimating spatially and temporally varying recharge and runoff from precipitation and urban irrigation in the Los Angeles Basin, California

    Science.gov (United States)

    Hevesi, Joseph A.; Johnson, Tyler D.

    2016-10-17

    A daily precipitation-runoff model, referred to as the Los Angeles Basin watershed model (LABWM), was used to estimate recharge and runoff for a 5,047 square kilometer study area that included the greater Los Angeles area and all surface-water drainages potentially contributing recharge to a 1,450 square kilometer groundwater-study area underlying the greater Los Angeles area, referred to as the Los Angeles groundwater-study area. The recharge estimates for the Los Angeles groundwater-study area included spatially distributed recharge in response to the infiltration of precipitation, runoff, and urban irrigation, as well as mountain-front recharge from surface-water drainages bordering the groundwater-study area. The recharge and runoff estimates incorporated a new method for estimating urban irrigation, consisting of residential and commercial landscape watering, based on land use and the percentage of pervious land area.The LABWM used a 201.17-meter gridded discretization of the study area to represent spatially distributed climate and watershed characteristics affecting the surface and shallow sub-surface hydrology for the Los Angeles groundwater study area. Climate data from a local network of 201 monitoring sites and published maps of 30-year-average monthly precipitation and maximum and minimum air temperature were used to develop the climate inputs for the LABWM. Published maps of land use, land cover, soils, vegetation, and surficial geology were used to represent the physical characteristics of the LABWM area. The LABWM was calibrated to available streamflow records at six streamflow-gaging stations.Model results for a 100-year target-simulation period, from water years 1915 through 2014, were used to quantify and evaluate the spatial and temporal variability of water-budget components, including evapotranspiration (ET), recharge, and runoff. The largest outflow of water from the LABWM was ET; the 100-year average ET rate of 362 millimeters per year (mm

  13. Comparing potential recharge estimates from three Land Surface Models across the Western US

    Science.gov (United States)

    NIRAULA, REWATI; MEIXNER, THOMAS; AJAMI, HOORI; RODELL, MATTHEW; GOCHIS, DAVID; CASTRO, CHRISTOPHER L.

    2018-01-01

    Groundwater is a major source of water in the western US. However, there are limited recharge estimates available in this region due to the complexity of recharge processes and the challenge of direct observations. Land surface Models (LSMs) could be a valuable tool for estimating current recharge and projecting changes due to future climate change. In this study, simulations of three LSMs (Noah, Mosaic and VIC) obtained from the North American Land Data Assimilation System (NLDAS-2) are used to estimate potential recharge in the western US. Modeled recharge was compared with published recharge estimates for several aquifers in the region. Annual recharge to precipitation ratios across the study basins varied from 0.01–15% for Mosaic, 3.2–42% for Noah, and 6.7–31.8% for VIC simulations. Mosaic consistently underestimates recharge across all basins. Noah captures recharge reasonably well in wetter basins, but overestimates it in drier basins. VIC slightly overestimates recharge in drier basins and slightly underestimates it for wetter basins. While the average annual recharge values vary among the models, the models were consistent in identifying high and low recharge areas in the region. Models agree in seasonality of recharge occurring dominantly during the spring across the region. Overall, our results highlight that LSMs have the potential to capture the spatial and temporal patterns as well as seasonality of recharge at large scales. Therefore, LSMs (specifically VIC and Noah) can be used as a tool for estimating future recharge rates in data limited regions. PMID:29618845

  14. Improving large-scale groundwater models by considering fossil gradients

    Science.gov (United States)

    Schulz, Stephan; Walther, Marc; Michelsen, Nils; Rausch, Randolf; Dirks, Heiko; Al-Saud, Mohammed; Merz, Ralf; Kolditz, Olaf; Schüth, Christoph

    2017-05-01

    Due to limited availability of surface water, many arid to semi-arid countries rely on their groundwater resources. Despite the quasi-absence of present day replenishment, some of these groundwater bodies contain large amounts of water, which was recharged during pluvial periods of the Late Pleistocene to Early Holocene. These mostly fossil, non-renewable resources require different management schemes compared to those which are usually applied in renewable systems. Fossil groundwater is a finite resource and its withdrawal implies mining of aquifer storage reserves. Although they receive almost no recharge, some of them show notable hydraulic gradients and a flow towards their discharge areas, even without pumping. As a result, these systems have more discharge than recharge and hence are not in steady state, which makes their modelling, in particular the calibration, very challenging. In this study, we introduce a new calibration approach, composed of four steps: (i) estimating the fossil discharge component, (ii) determining the origin of fossil discharge, (iii) fitting the hydraulic conductivity with a pseudo steady-state model, and (iv) fitting the storage capacity with a transient model by reconstructing head drawdown induced by pumping activities. Finally, we test the relevance of our approach and evaluated the effect of considering or ignoring fossil gradients on aquifer parameterization for the Upper Mega Aquifer (UMA) on the Arabian Peninsula.

  15. Hydrogeological Conditions of a Crystalline Aquifer: Simulation of Optimal Abstraction Rates under Scenarios of Reduced Recharge

    Science.gov (United States)

    Fynn, Obed Fiifi; Chegbeleh, Larry Pax; Nude, Prosper M.; Asiedu, Daniel K.

    2013-01-01

    A steady state numerical groundwater flow model has been calibrated to characterize the spatial distribution of a key hydraulic parameter in a crystalline aquifer in southwestern Ghana. This was to provide an initial basis for characterizing the hydrogeology of the terrain with a view to assisting in the large scale development of groundwater resources for various uses. The results suggest that the structural entities that control groundwater occurrence in the area are quite heterogeneous in their nature and orientation, ascribing hydraulic conductivity values in the range of 4.5 m/d to over 70 m/d to the simulated aquifer. Aquifer heterogeneities, coupled possibly with topographical trends, have led to the development of five prominent groundwater flowpaths in the area. Estimated groundwater recharge at calibration ranges between 0.25% and 9.13% of the total annual rainfall and appears to hold significant promise for large-scale groundwater development to support irrigation schemes. However, the model suggests that with reduced recharge by up to 30% of the current rates, the system can only sustain increased groundwater abstraction by up to 150% of the current abstraction rates. Prudent management of the resource will require a much more detailed hydrogeological study that identifies all the aquifers in the basin for the assessment of sustainable basin yield. PMID:24453882

  16. Simulation of groundwater flow and interaction of groundwater and surface water on the Lac du Flambeau Reservation, Wisconsin

    Science.gov (United States)

    Juckem, Paul F.; Fienen, Michael N.; Hunt, Randall J.

    2014-01-01

    The Lac du Flambeau Band of Lake Superior Chippewa and Indian Health Service are interested in improving the understanding of groundwater flow and groundwater/surface-water interaction on the Lac du Flambeau Reservation (Reservation) in southwest Vilas County and southeast Iron County, Wisconsin, with particular interest in an understanding of the potential for contamination of groundwater supply wells and the fate of wastewater that is infiltrated from treatment lagoons on the Reservation. This report describes the construction, calibration, and application of a regional groundwater flow model used to simulate the shallow groundwater flow system of the Reservation and water-quality results for groundwater and surface-water samples collected near a system of waste-water-treatment lagoons. Groundwater flows through a permeable glacial aquifer that ranges in thickness from 60 to more than 200 feet (ft). Seepage and drainage lakes are common in the area and influence groundwater flow patterns on the Reservation. A two-dimensional, steady-state analytic element groundwater flow model was constructed using the program GFLOW. The model was calibrated by matching target water levels and stream base flows through the use of the parameter-estimation program, PEST. Simulated results illustrate that groundwater flow within most of the Reservation is toward the Bear River and the chain of lakes that feed the Bear River. Results of analyses of groundwater and surface-water samples collected downgradient from the wastewater infiltration lagoons show elevated levels of ammonia and dissolved phosphorus. In addition, wastewater indicator chemicals detected in three downgradient wells and a small downgradient stream indicate that infiltrated wastewater is moving southwest of the lagoons toward Moss Lake. Potential effects of extended wet and dry periods (within historical ranges) were evaluated by adjusting precipitation and groundwater recharge in the model and comparing the

  17. Spatial and temporal changes in sulphate-reducing groundwater bacterial community structure in response to Managed Aquifer Recharge.

    Science.gov (United States)

    Reed, D A; Toze, S; Chang, B

    2008-01-01

    The population dynamics of bacterial able to be cultured under sulphate reducing condition was studied in conjunction with changes in aquifer geochemistry using multivariate statistics for two contrasting Managed Aquifer Recharge (MAR) techniques at two different geographical locations (Perth, Western Australia and Adelaide, South Australia). Principal component analysis (PCA) was used to investigate spatial and temporal changes in the overall chemical signature of the aquifers using an array of chemical analytes which demonstrated a migrating geochemical plume. Denaturing Gradient Gel Electrophoresis (DGGE) using DNA from sulphate-reducing bacteria cultures was used to detect spatial and temporal changes in population dynamics. Bacterial and geochemical evidence suggested that groundwater at greatest distance from the nutrient source was least affected by treated effluent recharge. The results suggested that bacterial populations that were able to be cultured in sulphate reducing media responded to the migrating chemical gradient and to the changes in aquifer geochemistry. Most noticeably, sulphate-reducing bacterial populations associated with the infiltration galleries were stable in community structure over time. Additionally, the biodiversity of these culturable bacteria was restored when aquifer geochemistry returned to ambient conditions during the recovery phase at the Adelaide Aquifer Storage and Recovery site. Copyright CSIRO 2008.

  18. Enhancement of wadi recharge using dams coupled with aquifer storage and recovery wells

    KAUST Repository

    Missimer, Thomas M. M.

    2014-06-25

    Wadi channel recharge to the underlying alluvial aquifer is naturally limited by the flashy nature of flood events, evapotranspiration losses of water from the vadose zone, and aquifer heterogeneity, particularly low vertical hydraulic conductivity. Anthropogenic lowering of the water table in many wadi aquifers has also reduced the potential recharge by increasing the thickness of the vadose zone, causing interflow water loss from surface emergence and evaporation. A method to enhance recharge is to slow the flow within wadi channels by placement of dam structures, thereby ponding water and increasing the vertical head gradient to create a more rapid rate of infiltration and percolation. Effectiveness of wadi dams to enhance aquifer recharge reduces over time due to mud deposition within the reservoir caused by storm events. Up to 80 % of the water in old wadi reservoirs is lost to free-surface evaporation before infiltration and recharge can occur. One method to maintain or increase the rate of recharge is to convey clean water by gravity flow from the reservoir down-gradient to artificially recharge the aquifer using existing wells. This type of system is a low-cost and low-energy recharge method which could greatly enhance groundwater storage in wadi aquifers. Modeling results show that existing wells could store up to 1,000 m3/day under gravity-feed conditions and up to 3,900 m3/day with the shut-in of the well to produce a pressurized system. © 2014 Springer-Verlag Berlin Heidelberg.

  19. Groundwater budgets for Detrital, Hualapai, and Sacramento Valleys, Mohave County, Arizona, 2007-08

    Science.gov (United States)

    Garner, Bradley D.; Truini, Margot

    2011-01-01

    The United States Geological Survey, in cooperation with the Arizona Department of Water Resources, initiated an investigation of the hydrogeology and water resources of Detrital, Hualapai, and Sacramento Valleys in northwestern Arizona in 2005, and this report is part of that investigation. Water budgets were developed for Detrital, Hualapai, and Sacramento Valleys to provide a generalized understanding of the groundwater systems in this rural area that has shown some evidence of human-induced water-level declines. The valleys are within the Basin and Range physiographic province and consist of thick sequences of permeable alluvial sediment deposited into basins bounded by relatively less permeable igneous and metamorphic rocks. Long-term natural recharge rates (1940-2008) for the alluvial aquifers were estimated to be 1,400 acre-feet per year (acre-ft/yr) for Detrital Valley, 5,700 acre-ft/yr for Hualapai Valley, and 6,000 acre-ft/yr for Sacramento Valley. Natural discharge rates were assumed to be equal to natural recharge rates, on the basis of the assumption that all groundwater withdrawals to date have obtained water from groundwater storage. Groundwater withdrawals (2007-08) for the alluvial aquifers were less than 300 acre-ft/yr for Detrital Valley, about 9,800 acre-ft/yr for Hualapai Valley, and about 4,500 acre-ft/yr for Sacramento Valley. Incidental recharge from leaking water-supply pipes, septic systems, and wastewater-treatment plants accounted for about 35 percent of total recharge (2007-08) across the study area. Natural recharge and discharge values in this study were 24-50 percent higher than values in most previously published studies. Water budgets present a spatially and temporally "lumped" view of water resources and incorporate many sources of uncertainty in this study area where only limited data presently are available.

  20. Tracer test modeling for characterizing heterogeneity and local scale residence time distribution in an artificial recharge site.

    Science.gov (United States)

    Valhondo, Cristina; Martinez-Landa, Lurdes; Carrera, Jesús; Hidalgo, Juan J.; Ayora, Carlos

    2017-04-01

    Artificial recharge of aquifers (AR) is a standard technique to replenish and enhance groundwater resources, that have widely been used due to the increasing demand of quality water. AR through infiltration basins consists on infiltrate surface water, that might be affected in more or less degree by treatment plant effluents, runoff and others undesirables water sources, into an aquifer. The water quality enhances during the passage through the soil and organic matter, nutrients, organic contaminants, and bacteria are reduced mainly due to biodegradation and adsorption. Therefore, one of the goals of AR is to ensure a good quality status of the aquifer even if lesser quality water is used for recharge. Understand the behavior and transport of the potential contaminants is essential for an appropriate management of the artificial recharge system. The knowledge of the flux distribution around the recharge system and the relationship between the recharge system and the aquifer (area affected by the recharge, mixing ratios of recharged and native groundwater, travel times) is essential to achieve this goal. Evaluate the flux distribution is not always simple because the complexity and heterogeneity of natural systems. Indeed, it is not so much regulate by hydraulic conductivity of the different geological units as by their continuity and inter-connectivity particularly in the vertical direction. In summary for an appropriate management of an artificial recharge system it is needed to acknowledge the heterogeneity of the media. Aiming at characterizing the residence time distribution (RTDs) of a pilot artificial recharge system and the extent to which heterogeneity affects RTDs, we performed and evaluated a pulse injection tracer test. The artificial recharge system was simulated as a multilayer model which was used to evaluate the measured breakthrough curves at six monitoring points. Flow and transport parameters were calibrated under two hypotheses. The first