Fisher, A. T.; Coburn, C.; Kiparsky, M.; Lockwood, B. S.; Bannister, M.; Camara, K.; Lozano, S.
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
Ajami, H.; Hogan, J.; Maddock, T.; Meixner, T.
Water managers are increasingly concerned about the potential impact of climate variability and change on groundwater resources. Climate impacts on groundwater resources are primarily determined by altering the amount of recharge and evapotranspiration (ET). Typically, groundwater models employ temporally static recharge or ET rates with limited spatial variability across the basin. As a result most groundwater models cannot be used to assess the impacts of climate on groundwater resources. A primary challenge addressing this shortcoming is the need for spatially and temporally explicit recharge and ET model inputs. Geographic Information Systems (GIS) and spatially explicit data can be applied to develop these improved model inputs by quantifying and distributing recharge and ET across the model domain. Two ArcGIS desktop applications were developed for ArcGIS 9.2 to enhance recharge and ET estimation- Arc- Recharge and RIPGIS-NET. Arc-Recharge an ArcGIS 9.2 custom application is developed to quantify and distribute recharge along MODFLOW cells. Using spatially explicit precipitation data and Digital Elevation Model (DEM), Arc-Recharge routes water through the landscape and distributes the recharge to the appropriate groundwater model cells. RIPGIS-NET is an ArcGIS custom application that was developed to provide parameters for the RIP-ET package. RIP-ET is an improved MODFLOW ET module that simulates ET using a set of eco-physiologically based ET curves. RIPGIS-NET improves alluvial recharge estimation by providing spatially explicit information about the riparian/wetland ET. Application of Arc-Recharge and RIPGIS-NET in groundwater modeling enhances recharge and ET estimation by incorporating temporally and spatially explicit data. Using such tools, assessment of climate variability on groundwater resources will be enhanced.
Szilagyi, Jozsef; Jozsa, Janos
Monthly evapotranspiration (ET) rates (2000 to 2009) across Nebraska at about 1-km resolution were obtained by linear transformations of the MODIS (MODerate resolution Imaging Spectroradiometer) daytime surface temperature values with the help of the Priestley-Taylor equation and the complementary relationship of evaporation. For positive values of the mean annual precipitation and ET differences, the mean annual net recharge was found by an additional multiplication of the power-function-transformed groundwater vulnerability DRASTIC-code values. Statewide mean annual net recharge became about 29 mm (i.e., 5% of mean annual precipitation) with the largest recharge rates (in excess of 100 mm/year) found in the eastern Sand Hills and eastern Nebraska. Areas with the largest negative net recharge rates caused by declining groundwater levels due to large-scale irrigation are found in the south-western region of the state. Error bounds of the estimated values are within 10% to 15% of the corresponding precipitation rates and the estimated net recharge rates are sensitive to errors in the precipitation and ET values. This study largely confirms earlier base-flow analysis-based statewide groundwater recharge estimates when considerations are made for differences in the recharge definitions. The current approach not only provides better spatial resolution than available earlier studies for the region but also quantifies negative net recharge rates that become especially important in numerical modeling of shallow groundwater systems. © 2012, The Author(s). Groundwater © 2012, National Ground Water Association.
Szilagyi, Jozsef; Zlotnik, Vitaly A; Jozsa, Janos
One-km resolution MODIS-based mean annual evapotranspiration (ET) estimates in combination with PRISM precipitation rates were correlated with depth to groundwater (d) values in the wide alluvial valley of the Platte River in Nebraska for obtaining a net recharge (Rn) vs. d relationship. MODIS cells with irrigation were excluded, yielding a mixture of predominantly range, pasture, grass, and riparian forest covers on sandy soils with a shallow groundwater table. The transition depth (dt ) between negative and positive values of the net groundwater recharge was found to be at about 2 (±1) m. Within 1 (±1) m of the surface and at a depth larger than about 7 to 8 (±1) m, the mean annual net recharge became independent of d at a level of about -4 (±12)% and 13 (±10)%, respectively, of the mean annual precipitation rate. The obtained Rn(d) relationship is based on a calibration-free ET estimation method and may help in obtaining the net recharge in shallow groundwater areas of negligible surface runoff where sufficient groundwater-depth data exist. © 2012, The Author(s). Groundwater © 2012, National Ground Water Association.
Bugan, Richard DH
Full Text Available Groundwater recharge is the basis for accurate estimation of groundwater resources, for determining the modes of water allocation and groundwater resource susceptibility to climate change. Accurate estimations of groundwater recharge with models...
The existing knowledge base regarding the presence and significance of chemicals foreign to the subsurface environment is large and growing -the papers in this volume serving as recent testament. But complex questions with few answers surround the unknowns regarding the potential for environmental or human health effects from trace levels of xenobiotics in groundwater, especially groundwater augmented with treated wastewater. Public acceptance for direct or indirect groundwater recharge using treated municipal wastewater ( especially sewage) spans the spectrum from unquestioned embrace to outright rejection. In this article, I detour around the issues most commonly discussed for groundwater recharge and instead focus on some of the less-recognized issues- those that emanate from the mysteries created at the many literal and virtual interfaces involved with the subsurface world. My major objective is to catalyze discussion that advances our understanding of the barriers to public acceptance of wastewater reuse -with its ultimate culmination in direct reuse for drinking. I pose what could be a key question as to whether much of the public's frustration or ambivalence in its decision making process for accepting or rejecting water reuse (for various purposes including personal use) emanates from fundamental inaccuracies, misrepresentation, or oversimplification of what water 'is' and how it functions in the environment -just what exactly is the 'water cyc
Doble, Rebecca C.; Pickett, Trevor; Crosbie, Russell S.; Morgan, Leanne K.; Turnadge, Chris; Davies, Phil J.
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.
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.
Estimation of natural groundwater recharge is a pre-requisite for efficient groundwater resource management especially in regions with large demands for groundwater supplies, where such resources are the key to economic development. Groundwater recharge, by whatever method, is normally subjected to large ...
Baseflow recession analyses of Yewa and Ona rivers were carried out with a view to determining and comparing groundwater recharge in parts of the sedimentary and Basement Complex terrains of Southwestern Nigeria. Daily discharges of the rivers for ten years (1988 – 1997) were analysed. Groundwater recharge in ...
Then Bima Sandstone aquifer is the main water resource in the semi-arid Yola area of Northeastern, Nigeria. The rapid increase in water demand in this area has prompted the need to estimate available groundwater recharge for sustainable utilization. Groundwater recharge estimation methods and results are compared: ...
Apr 2, 2005 ... to change in the value of specific yield than hydraulic conductivity. Keywords: finite difference model, groundwater recharge, surface drain, water table. List of symbols a. = area of cross-section of flow at any z ..... avg. wt = Q(t)/(2L*drl). (23). Figure 2. Flow chart of the groundwater recharge model for surface.
Han, Dongmei; Currell, Matthew J.; Cao, Guoliang; Hall, Benjamin
The impacts of anthropogenic modifications to the landscape on groundwater recharge rates, locations, and mechanisms are reviewed. The two major categories of change examined are conversion of land for agriculture and urbanization, both of which have significant effects on groundwater recharge. Techniques for identifying and quantifying the changes in recharge due to these impacts are discussed. Land-clearing for agriculture and surface water transfer for irrigation have resulted in order of magnitude increases in recharge rates in many semi-arid regions worldwide, causing ongoing land and water salinization and water-logging problems. While increased recharge by irrigation return flow may alleviate shallow groundwater depletion in some settings, this is complicated by the effect of unsaturated zone thickening, which reduces the fraction of potential recharge becoming actual recharge, and may result in new water quality risks such as nitrate contamination. Expansion of urban and peri-urban land and their associated surface and sub-surface infrastructure results in complex water balance changes that re-distribute groundwater recharge locations, modify recharge mechanism(s) and result in variable impacts on recharge rates (e.g., overall net decrease, increase or minimal change) and quality. While changes to groundwater recharge resulting from conversion of land for agriculture are relatively well understood, less is documented about the changes resulting from urbanization, due to a paucity of data from field-based studies. Two case studies from Beijing, China and Melbourne Australia are examined, which highlight these impacts and demonstrate some potential methodological techniques for this topic.
Tubau, Isabel; Vázquez-Suñé, Enric; Carrera, Jesús; Valhondo, Cristina; Criollo, Rotman
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.
Saul'yev V K 1964 Integration of the equation of the parabolic type by the method of nets (Oxford; Pergamon. Press). Srivastava V K 1976 Study of induced groundwater recharge, Ph.D. Thesis, Indian Institute of Technology,. New Delhi. Thomas Jr H A, Burden R P 1965 Indus river basin studies (mimeo) Division of ...
Boonstra, J.; Bhutta, M.N.
Quantifying the rate of natural groundwater recharge is a prerequisite for drainage design in waterlogged areas. The present study was aimed at determining the seasonal net recharge in the Schedule I-B area of the Fourth Drainage Project, Faisalabad, Pakistan. A numerical groundwater model was
Döll, P.; Fiedler, K.
Long-term average groundwater recharge, which is equivalent to renewable groundwater resources, is the major limiting factor for the sustainable use of groundwater. Compared to surface water resources, groundwater resources are more protected from pollution, and their use is less restricted by seasonal and inter-annual flow variations. To support water management in a globalized world, it is necessary to estimate groundwater recharge at the global scale. Here, we present a best estimate of global-scale long-term average diffuse groundwater recharge (i.e. renewable groundwater resources) that has been calculated by the most recent version of the WaterGAP Global Hydrology Model WGHM (spatial resolution of 0.5° by 0.5°, daily time steps). The estimate was obtained using two state-of-the-art global data sets of gridded observed precipitation that we corrected for measurement errors, which also allowed to quantify the uncertainty due to these equally uncertain data sets. The standard WGHM groundwater recharge algorithm was modified for semi-arid and arid regions, based on independent estimates of diffuse groundwater recharge, which lead to an unbiased estimation of groundwater recharge in these regions. WGHM was tuned against observed long-term average river discharge at 1235 gauging stations by adjusting, individually for each basin, the partitioning of precipitation into evapotranspiration and total runoff. We estimate that global groundwater recharge was 12 666 km3/yr for the climate normal 1961-1990, i.e. 32% of total renewable water resources. In semi-arid and arid regions, mountainous regions, permafrost regions and in the Asian Monsoon region, groundwater recharge accounts for a lower fraction of total runoff, which makes these regions particularly vulnerable to seasonal and inter-annual precipitation variability and water pollution. Average per-capita renewable groundwater resources of countries vary between 8 m3/(capita yr) for Egypt to more than 1 million m3
Döll, P.; Fiedler, K.
Long-term average groundwater recharge, which is equivalent to renewable groundwater resources, is the major limiting factor for the sustainable use of groundwater. Compared to surface water resources, groundwater resources are more protected from pollution, and their use is less restricted by seasonal and inter-annual flow variations. To support water management in a globalized world, it is necessary to estimate groundwater recharge at the global scale. Here, we present a best estimate of global-scale long-term average diffuse groundwater recharge (i.e. renewable groundwater resources) that has been calculated by the most recent version of the WaterGAP Global Hydrology Model WGHM (spatial resolution of 0.5° by 0.5°, daily time steps). The estimate was obtained using two state-of-the art global data sets of gridded observed precipitation that we corrected for measurement errors, which also allowed to quantify the uncertainty due to these equally uncertain data sets. The standard WGHM groundwater recharge algorithm was modified for semi-arid and arid regions, based on independent estimates of diffuse groundwater recharge, which lead to an unbiased estimation of groundwater recharge in these regions. WGHM was tuned against observed long-term average river discharge at 1235 gauging stations by adjusting, individually for each basin, the partitioning of precipitation into evapotranspiration and total runoff. We estimate that global groundwater recharge was 12 666 km3/yr for the climate normal 1961-1990, i.e. 32% of total renewable water resources. In semi-arid and arid regions, mountainous regions, permafrost regions and in the Asian Monsoon region, groundwater recharge accounts for a lower fraction of total runoff, which makes these regions particularly vulnerable to seasonal and inter-annual precipitation variability and water pollution. Average per-capita renewable groundwater resources of countries vary between 8 m3/(capita yr) for Egypt to more than 1 million m3
Full Text Available Long-term average groundwater recharge, which is equivalent to renewable groundwater resources, is the major limiting factor for the sustainable use of groundwater. Compared to surface water resources, groundwater resources are more protected from pollution, and their use is less restricted by seasonal and inter-annual flow variations. To support water management in a globalized world, it is necessary to estimate groundwater recharge at the global scale. Here, we present a best estimate of global-scale long-term average diffuse groundwater recharge (i.e. renewable groundwater resources that has been calculated by the most recent version of the WaterGAP Global Hydrology Model WGHM (spatial resolution of 0.5° by 0.5°, daily time steps. The estimate was obtained using two state-of-the-art global data sets of gridded observed precipitation that we corrected for measurement errors, which also allowed to quantify the uncertainty due to these equally uncertain data sets. The standard WGHM groundwater recharge algorithm was modified for semi-arid and arid regions, based on independent estimates of diffuse groundwater recharge, which lead to an unbiased estimation of groundwater recharge in these regions. WGHM was tuned against observed long-term average river discharge at 1235 gauging stations by adjusting, individually for each basin, the partitioning of precipitation into evapotranspiration and total runoff. We estimate that global groundwater recharge was 12 666 km3/yr for the climate normal 1961–1990, i.e. 32% of total renewable water resources. In semi-arid and arid regions, mountainous regions, permafrost regions and in the Asian Monsoon region, groundwater recharge accounts for a lower fraction of total runoff, which makes these regions particularly vulnerable to seasonal and inter-annual precipitation variability and water pollution. Average per-capita renewable groundwater resources of countries vary between 8 m3
Healy, R.W.; Cook, P.G.
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.
Abdullahi, Musa Garba; Kamarudin, Mohd Khairul Amri; Toriman, Mohd Ekhwan; Gasim, Muhammad Barzani; Endut, Azizah; Garba, Iliyasu
Estimation of groundwater recharge is essential for efficient groundwater resources management, for domestic uses and irrigation purposes in the study area. The present research entails the assessment of natural groundwater recharge in Terengganu Malaysia. Estimation of recharge by whatever method is usually subjected to a large uncertaintyand errors. However, this research attempt to derive an empirical relationship to determine the groundwater recharge from rainfall based on seasonal ground...
Mathias, Simon A.; Sorensen, James P.R.; Butler, Adrian P.
Estimating groundwater recharge rates is important for water resource management studies. Modeling approaches to forecast groundwater recharge typically require observed historic data to assist calibration. It is generally not possible to observe groundwater recharge rates directly. Therefore, in the past, much effort has been invested to record soil moisture content (SMC) data, which can be used in a water balance calculation to estimate groundwater recharge. In this context, SMC data is mea...
Groundwater Recharge, Evapotranspiration and Surface Runoff Estimation Using WetSpass Modeling Method in Illala Catchment, Northern Ethiopia. ... Abstract. Hydrometeorological information is important in planning and management of natural resources. The northern Ethiopia in general and Illala sub-basin in particular ...
this unit at different parts of the catchment. Hence, in the ... decrease currently due to different soil and water conservation practices conducted especially in .... water body. Actual evapotranspiration is one components of water balance to determine groundwater recharge of Illala catchment using the WetSpass model.
storage studies and their application to the determination of infiltration. Trans Am. Geopys. Union 19:435-445. Larsen F, Owen R, Dahlin T, and Mangeya, P., 2002. A preliminary analysis of the groundwater recharge to the Karoo Formations, ...
Tan, Xiu-Cui; Wu, Jing-Wei; Cai, Shu-Ying; Yang, Jin-Zhong
Groundwater recharge is an important component of the groundwater system. On the North China Plain (NCP), groundwater is the main water supply. Because of large-scale overexploitation, the water table has declined, which has produced severe adverse effects on the environment and ecosystem. In this article, tracer experiment and watershed model were used to calculate and analyze NCP groundwater recharge. In the tracer experiment, average recharge was 108 mm/year and recharge coefficient 0.16. With its improved irrigation, vegetation coverage and evapotranspiration modules, the INFIL3.0 model was used for calculation of groundwater recharge. Regional modeling results showed an average recharge of 102 mm/year and recharge coefficient 0.14, for 2001-2009. These values are very similar to those from the field tracer experiment. Influences in the two methods were analyzed. The results can provide an important reference for NCP groundwater recharge. © 2013, National Ground Water Association.
McKenna, Owen P.; Sala, Osvaldo E.
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.
The purpose of the study is to inform valuation of groundwater recharge from stormwater retention in areas projected for new development and redevelopment. This study examined a simplified methodology for estimating recharge volume.
De Silva, RP
The spatial variability of recharge is an important consideration in estimating recharge especially as all methods of estimating it are 'point' estimates and in most places recharge varies in space. This paper along with the accompanying paper attempts to find a suitable answer to the question of taking this variability into account in estimating groundwater recharge. This paper attempts to determine if recharge is actually varying in space and that this is 'true' variability and that it is n...
Santos, Isaac R; Zhang, Chenming; Maher, Damien T; Atkins, Marnie L; Holland, Rodney; Morgenstern, Uwe; Li, Ling
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 recharge. The highest recharge 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.
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.
U.S. Geological Survey, Department of the Interior — Recharge in the Death Valley regional ground-water flow system (DVRFS) was estimated from net infiltration simulated by Hevesi and others (2003) using a...
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 ...
Snowmelt in the mountainous areas of the Table Mountain Group (TMG) in South Africa is believed to be one of sources of groundwater recharge in some winter seasons. This paper provides a scientific assessment of snow impact on groundwater recharge in Table Mountain Group Aquifer Systems for the first time.
Mathias, Simon A.; Sorensen, James P. R.; Butler, Adrian P.
Estimating groundwater recharge rates is important for water resource management studies. Modeling approaches to forecast groundwater recharge typically require observed historic data to assist calibration. It is generally not possible to observe groundwater recharge rates directly. Therefore, in the past, much effort has been invested to record soil moisture content (SMC) data, which can be used in a water balance calculation to estimate groundwater recharge. In this context, SMC data is measured at different depths and then typically integrated with respect to depth to obtain a single set of aggregated SMC values, which are used as an estimate of the total water stored within a given soil profile. This article seeks to investigate the value of such aggregated SMC data for conditioning groundwater recharge models in this respect. A simple modeling approach is adopted, which utilizes an emulation of Richards' equation in conjunction with a soil texture pedotransfer function. The only unknown parameters are soil texture. Monte Carlo simulation is performed for four different SMC monitoring sites. The model is used to estimate both aggregated SMC and groundwater recharge. The impact of conditioning the model to the aggregated SMC data is then explored in terms of its ability to reduce the uncertainty associated with recharge estimation. Whilst uncertainty in soil texture can lead to significant uncertainty in groundwater recharge estimation, it is found that aggregated SMC is virtually insensitive to soil texture.
Smerdon, Brian D.; Drewes, Jörg E.
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).
Chen, Wei-Ping; Lü, Si-Dan; Wang, Mei-E; Jiao, Wen-Tao
Reclaimed water recharge to groundwater is an effective way to relieve water resource crisis. However, reclaimed water contains some pollutants such as nitrate, heavy metals, and new type contaminants, and thus, there exists definite environmental risk in the reclaimed water recharge to groundwater. To promote the development of reclaimed water recharge to groundwater and the safe use of reclaimed water in China, this paper analyzed the relevant literatures and practical experiences around the world, and summarized the effects of different reclaimed water recharge modes on the groundwater quality. Surface recharge makes the salt and nitrate contents in groundwater increased but the risk of heavy metals pollution be smaller, whereas well recharge can induce the arsenic release from sedimentary aquifers, which needs to be paid more attention to. New type contaminants are the hotspots in current researches, and their real risks are unknown. Pathogens have less pollution risks on groundwater, but some virus with strong activity can have the risks. Some suggestions were put forward to reduce the risks associated with the reclaimed water recharge to groundwater in China.
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 ...
Ayvaz, M Tamer; Elçi, Alper
The quantification of groundwater recharge is an important but challenging task in groundwater flow modeling because recharge varies spatially and temporally. The goal of this study is to present an innovative methodology to estimate groundwater recharge rates and zone structures for regional groundwater flow models. Here, the unknown recharge field is partitioned into a number of zones using Voronoi Tessellation (VT). The identified zone structure with the recharge rates is associated through a simulation-optimization model that couples MODFLOW-2000 and the hybrid PSOLVER optimization algorithm. Applicability of this procedure is tested on a previously developed groundwater flow model of the Tahtalı Watershed. Successive zone structure solutions are obtained in an additive manner and penalty functions are used in the procedure to obtain realistic and plausible solutions. One of these functions constrains the optimization by forcing the sum of recharge rates for the grid cells that coincide with the Tahtalı Watershed area to be equal to the areal recharge rate determined in the previous modeling by a separate precipitation-runoff model. As a result, a six-zone structure is selected as the best zone structure that represents the areal recharge distribution. Comparison to results of a previous model for the same study area reveals that the proposed procedure significantly improves model performance with respect to calibration statistics. The proposed identification procedure can be thought of as an effective way to determine the recharge zone structure for groundwater flow models, in particular for situations where tangible information about groundwater recharge distribution does not exist. © 2013, National Ground Water Association.
He, H. Y.; Shi, X. F.; Zhu, W.; Wang, C. Q.; Ma, H. W.; Zhang, W. J.
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.
O. V. Barron; R. S. Crosbie; Pollock, D.; W. R. Dawes; Charles, S. P.; Pickett, T.; M. Donn
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 modeling 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 t...
O. V. Barron; R. S. Crosbie; W. R. Dawes; Charles, S. P.; Pickett, T.; Donn, M. J.
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 ...
Knowling, Matthew J; Werner, Adrian D
The estimation of recharge through groundwater model calibration is hampered by the nonuniqueness of recharge and aquifer parameter values. It has been shown recently that the estimability of spatially distributed recharge through calibration of steady-state models for practical situations (i.e., real-world, field-scale aquifer settings) is limited by the need for excessive amounts of hydraulic-parameter and groundwater-level data. However, the extent to which temporal recharge variability can be informed through transient model calibration, which involves larger water-level datasets, but requires the additional consideration of storage parameters, is presently unknown for practical situations. In this study, time-varying recharge estimates, inferred through calibration of a field-scale highly parameterized groundwater model, are systematically investigated subject to changes in (1) the degree to which hydraulic parameters including hydraulic conductivity (K) and specific yield (S y ) are constrained, (2) the number of water-level calibration targets, and (3) the temporal resolution (up to monthly time steps) at which recharge is estimated. The analysis involves the use of a synthetic reality (a reference model) based on a groundwater model of Uley South Basin, South Australia. Identifiability statistics are used to evaluate the ability of recharge and hydraulic parameters to be estimated uniquely. Results show that reasonable estimates of monthly recharge (recharge root-mean-squared error) require a considerable amount of transient water-level data, and that the spatial distribution of K is known. Joint estimation of recharge, S y and K, however, precludes reasonable inference of recharge and hydraulic parameter values. We conclude that the estimation of temporal recharge variability through calibration may be impractical for real-world settings. © 2017, National Ground Water Association.
Dvory, N. Z.; Livshitz, Y.; Adar, E.; Kuznetsov, M.; Yakirevich, A.
Accurate estimation of groundwater recharge is important to evaluate aquifer's water balance. Spatial and temporal distribution of the recharge depends on variability of hydraulic properties of rock. This variability is larger for sedimentary fractured environments where fast and slow flow paths exist. Therefore, quantifying groundwater fluxes through various rock sections within the vadose zone and into the aquifer is of critical importance for determining aquifers storage deviation. The research objective was to investigate how the lithology changes influence flow in the unsaturated zone and the spatial and temporal variation of groundwater recharge. To assess these variations for the Western Mountain Aquifer (Yarkon-Taninim) of Israel, we considered a range of parameters values for both fractures/karst and porous media, namely; permeability, block size, spacing between fractures, karst volumetric volume, etc. A conceptual model was built for nine monitoring wells sites in the study area. A one-dimensional, dual permeability mathematical model of water flow in a variably saturated, fractured/karst-porous media was applied to simulate water flow in each location. Model parameters were determined by solving the inverse problem using data of groundwater level observations. The results of simulation show that the highest groundwater replenishment occurs in locations where fast flow paths conditions are expected, while the lowest recharges took place in locations containing low permeability layers. The spatial differences in recharge are larger during years with high precipitation which can reach a few hundred percent. Additionally, fast and slow flow paths conditions also influence annual cumulative groundwater recharge dynamic. In areas where fast flow paths exist, most of the groundwater recharge occurs during the rainy season (60-80% of the total recharge for the tested years), while in locations with slow flow path conditions the recharge rate stays relatively
Mohan, Chinchu; Western, Andrew W.; Wei, Yongping; Saft, Margarita
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. The aims of this study were to identify the most influential factors on groundwater recharge, and to develop an empirical model to estimate diffuse rainfall recharge at a glo...
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.
Soheili, Mahmoud; (Tom) Rientjes, T. H. M.; (Christiaan) van der Tol, C.
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
N. Somaratne; K. R. J. Smettem
Application of the conventional chloride mass balance (CMB) method to point recharge dominant groundwater basins can substantially under-estimate long-term average annual recharge by not accounting for the effects of localized surface water inputs. This is because the conventional CMB method ignores the duality of infiltration and recharge found in karstic systems, where point recharge can be a contributing factor. When point recharge is present in groundwater basins,...
Geronia, M. C. M.
For rapidly urbanizing areas, groundwater utilization has been subject to contentions concerning its allocation and supply. The Philippines, an industrializing and developing country, primarily taps surface water for supply but has been extracting groundwater in increasing amounts in recent years. Despite abundant rainfall, the recharge and rainfall proportion for the Philippines just ranges from 7 to 10 percent, causing low recharge rates. Iloilo, a developing metropolis in central Philippines, has started to run into groundwater supply shortages. The city has already been tapping 93% of its supply from deep aquifers for years but low and unpredictable recharge and lack of groundwater studies increase uncertainties to the city's water situation. This study analyzed the relationship among the city's volcanic and clastic multi-aquifer systems and groundwater recharge during the wet season. Constant-rate pumping tests were performed and time-drawdown data were collected on wells at different depths scattered across the city. Hydrographs were computed and analyzed for the basin to determine rainfall-recharge relationship for the aquifer system and were compared to available historical data. Results showed shallow aquifers with depths less than 20 meters, as expected, were still subject to recharge especially during wet season. However, urbanization and increased abstraction from unregulated wells further worsened by an El Niño-induced 6-month drought had started to dry up the shallow perched aquifers, resulting to a net decrease in available supply. Aquifer recharge at depths between 50 to 70 meters has decreased substantially, potentially threatening the city's water supply for the long term. Nonetheless, characterizing and quantifying the relationship of the Iloilo aquifer system and recharge have given a much better picture of the situation that will benefit the city in water resource planning and allocation in light of future hydrological and climate risks.
Full Text Available A Visual Basic spreadsheet macro was written to automate the estimation of groundwater recharge from stream or spring hydrographs using the adapted Meyboom’s method. The program fits exponential regression model available in widely accessible platform (i.e. MS Excel to baseflow recessions that precede and follow groundwater recharge, and uses regression equations to calculate recharge volume that occur between these recessions. An example of field data from Croatia (Bulaž spring is given to illustrate its application.
Hartmann, Andreas; Gleeson, Tom; Wada, Yoshihide; Wagener, Thorsten
Our environment is heterogeneous. In hydrological sciences, the heterogeneity of subsurface properties, such as hydraulic conductivities or porosities, exerts an important control on water balance. This notably includes groundwater recharge, which is an important variable for efficient and sustainable groundwater resources management. Current large-scale hydrological models do not adequately consider this subsurface heterogeneity. Here we show that regions with strong subsurface heterogeneity have enhanced present and future recharge rates due to a different sensitivity of recharge to climate variability compared with regions with homogeneous subsurface properties. Our study domain comprises the carbonate rock regions of Europe, Northern Africa, and the Middle East, which cover 25 of the total land area. We compare the simulations of two large-scale hydrological models, one of them accounting for subsurface heterogeneity. Carbonate rock regions strongly exhibit karstification, which is known to produce particularly strong subsurface heterogeneity. Aquifers from these regions contribute up to half of the drinking water supply for some European countries. Our results suggest that water management for these regions cannot rely on most of the presently available projections of groundwater recharge because spatially variable storages and spatial concentration of recharge result in actual recharge rates that are up to four times larger for present conditions and changes up to five times larger for potential future conditions than previously estimated. These differences in recharge rates for strongly heterogeneous regions suggest a need for groundwater management strategies that are adapted to the fast transit of water from the surface to the aquifers.
Stuart O. Reese,; Risser, Dennis W.
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
Full Text Available In this study, the stable isotope values of oxygen and hydrogen were used to identify the seasonal contribution ratios of precipitation to groundwater recharge in the Hualien River basin of eastern Taiwan. The differences and correlations of isotopes in various water bodies were examined to evaluate the groundwater recharge sources for the Hualian River basin and the interrelations between groundwater and surface water. Proportions of recharge sources were calculated based on the results of the mass balance analysis of the isotope composition of hydrogen and oxygen in the basin. Mountain river water accounted for 83% and plain rainfall accounted for 17% of the groundwater recharge in the Huanlian River basin. Using the mean d-values, a comparison of d-values of precipitation and groundwater indicates the groundwater consists of 75.5% wet seasonal sources and 24.5% dry seasonal sources, representing a distinct seasonal variation of groundwater recharge in the study area. Comparisons between hydrogen and oxygen isotopes in rainwater showed that differences in the amount of rainfall resulted in depleted oxygen and hydrogen isotopes for precipitation in wet seasons as compared to dry seasons. The river water contained more depleted hydrogen and oxygen isotopes than was the case for precipitation, implying that the river water mainly came from the upstream catchment. In addition, the hydrogen and oxygen isotopes in the groundwater slightly deviated from the hydrogen and oxygen isotopic meteoric water line in Huanlian. Therefore, the groundwater in this basin might be a mixture of river water and precipitation, resulting in the effect of the river water recharge being greater than that of rainfall infiltration.
Home; Journals; Journal of Earth System Science; Volume 123; Issue 3. GIS and SBF for estimating groundwater recharge of a ... The temporal and spatial distributions of precipitation are extremely uneven; so, careful management of water resources in Taiwan is crucial. The long-term overexploitation of groundwater ...
R. B. Bradford
Full Text Available Models of varying complexity are available to provide estimates of recharge in headwater Chalk catchments. Some measure of how estimates vary between different models can help guide the choice of model for a particular application. This paper compares recharge estimates derived from four models employing input data at varying spatial resolutions for a Chalk headwater catchment (River Pang, UK over a four-year period (1992-1995 that includes a range of climatic conditions. One model was validated against river flow data to provide a measure of their relative performance. Each model gave similar total recharge for the crucial winter recharge period when evaporation is low. However, the simple models produced relatively lower estimates of the summer and early autumn recharge due to the way in which processes governing recharge especially evaporation and infiltration are represented. The relative uniformity of land use, soil types and rainfall across headwater, drift-free Chalk catchments suggests that complex, distributed models offer limited benefits for recharge estimates at the catchment scale compared to simple models. Nonetheless, distributed models would be justified for studies where the pattern and amount of recharge need to be known in greater detail and to provide more reliable estimates of recharge during years with low rainfall. Keywords: Chalk, modelling, groundwater recharge
Yu, Hwa-Lung; Chu, Hone-Jay
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.
Moeck, Christian; Von Freyberg, Jana; Schrimer, Maria
An important question in recharge impact studies is how model choice, structure and calibration period affect recharge predictions. It is still unclear if a certain model type or structure is less affected by running the model on time periods with different hydrological conditions compared to the calibration period. This aspect, however, is crucial to ensure reliable predictions of groundwater recharge. In this study, we quantify and compare the effect of groundwater recharge model choice, model parametrization and calibration period in a systematic way. This analysis was possible thanks to a unique data set from a large-scale lysimeter in a pre-alpine catchment where daily long-term recharge rates are available. More specifically, the following issues are addressed: We systematically evaluate how the choice of hydrological models influences predictions of recharge. We assess how different parameterizations of models due to parameter non-identifiability affect predictions of recharge by applying a Monte Carlo approach. We systematically assess how the choice of calibration periods influences predictions of recharge within a differential split sample test focusing on the model performance under extreme climatic and hydrological conditions. Results indicate that all applied models (simple lumped to complex physically based models) were able to simulate the observed recharge rates for five different calibration periods. However, there was a marked impact of the calibration period when the complete 20 years validation period was simulated. Both, seasonal and annual differences between simulated and observed daily recharge rates occurred when the hydrological conditions were different to the calibration period. These differences were, however, less distinct for the physically based models, whereas the simpler models over- or underestimate the observed recharge depending on the considered season. It is, however, possible to reduce the differences for the simple models by
Scanlon, B.R.; Keese, K.E.; Flint, A.L.; Flint, L.E.; Gaye, C.B.; Edmunds, W.M.; Simmers, I.
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 (40-374000 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 Nin??o Southern Oscillation (ENSO) results in up to three times higher recharge in regions within the SW US during periods of frequent El Nin??os (1977-1998) relative to periods dominated by La Nin??as (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 the SW US. The
Scanlon, Bridget R.; Keese, Kelley E.; Flint, Alan L.; Flint, Lorraine E.; Gaye, Cheikh B.; Edmunds, W. Michael; Simmers, Ian
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 the SW US. The impact of LU
Hassane Maina, Fadji; Ackerer, Philippe; Bildstein, Olivier
By groundwater model calibration, we consider here fitting the measured piezometric heads by estimating the hydrodynamic parameters (storage term and hydraulic conductivity) and the recharge. It is traditionally recommended to avoid simultaneous calibration of groundwater recharge and flow parameters because of correlation between recharge and the flow parameters. From a physical point of view, little recharge associated with low hydraulic conductivity can provide very similar piezometric changes than higher recharge and higher hydraulic conductivity. If this correlation is true under steady state conditions, we assume that this correlation is much weaker under transient conditions because recharge varies in time and the parameters do not. Moreover, the recharge is negligible during summer time for many climatic conditions due to reduced precipitation, increased evaporation and transpiration by vegetation cover. We analyze our hypothesis through global sensitivity analysis (GSA) in conjunction with the polynomial chaos expansion (PCE) methodology. We perform GSA by calculating the Sobol indices, which provide a variance-based 'measure' of the effects of uncertain parameters (storage and hydraulic conductivity) and recharge on the piezometric heads computed by the flow model. The choice of PCE has the following two benefits: (i) it provides the global sensitivity indices in a straightforward manner, and (ii) PCE can serve as a surrogate model for the calibration of parameters. The coefficients of the PCE are computed by probabilistic collocation. We perform the GSA on simplified real conditions coming from an already built groundwater model dedicated to a subdomain of the Upper-Rhine aquifer (geometry, boundary conditions, climatic data). GSA shows that the simultaneous calibration of recharge and flow parameters is possible if the calibration is performed over at least one year. It provides also the valuable information of the sensitivity versus time, depending on
Reichard, Eric G.; Bredehoeft, John D.
This study describes and demonstrates two alternate methods for evaluating the relative costs and benefits of artificial groundwater recharge using percolation ponds. The first analysis considers the benefits to be the reduction of pumping lifts and land subsidence; the second considers benefits as the alternative costs of a comparable surface delivery system. Example computations are carried out for an existing artificial recharge program in Santa Clara Valley in California. A computer groundwater model is used to estimate both the average long term and the drought period effects of artificial recharge in the study area. Results indicate that the costs of artificial recharge are considerably smaller than the alternative costs of an equivalent surface system. Refs.
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.
Dabral, S.; Bhatt, B.; Joshi, J. P.; Sharma, N.
Groundwater quality in Gujarat state is highly variable and due to multiplicity of factors viz. influenced by direct sea water encroachment, inherent sediment salinity, water logging, overexploitation leading to overall deterioration in ground water quality, coupled with domestic and industrial pollution etc. The groundwater scenario in the state is not very encouraging due to imbalance between recharge and groundwater exploitation. Further, the demand for water has increased manifold owing to agricultural, industrial and domestic requirement and this has led to water scarcity in many parts of the state, which is likely to become more severe in coming future due to both natural and manmade factors. Therefore, sustainable development of groundwater resource requires precise quantitative assessment based on reasonably valid scientific principles. Hence, delineation of groundwater potential zones (GWPZ), has acquired great significance. The present study focuses on the integrated Geospatial and Multi-Criteria Decision Making (MCDM) techniques to determine the most important contributing factors that affect the groundwater resources and also to delineate the potential zones for groundwater recharge. The multiple thematic layers of influencing parameters viz. geology, geomorphology, soil, slope, drainage density and land use, weightages were assigned to the each factor according to their relative importance as per subject experts opinion owing to the natural setup of the region. The Analytical Hierarchy Process (AHP) was applied to these factors and potential recharge zones were identified. The study area for the assessment of groundwater recharge potential zones is Mahi-Narmada inter-stream region of Gujarat state. The study shows that around 28 % region has the excellent suitability of the ground water recharge.
The results of a 6 year recharge study in the Great Bend Prairie of central Kansas are statistically analyzed to regionalize the limited number of site-specific but year-round measurements. Emphasis is placed on easily measured parameters and field-measured data. The results of the statistical analysis reveal that a typical recharge event in central Kansas lasts 5-7 days, out of which 3 or 4 days are precipitation days with total precipitation of ??? 83 mm. The maximum soil-profile water storage and the maximum groundwater level resulting from the recharge event exhibit the lowest coefficients of variation, whereas the amount of recharge exhibits the highest coefficient of variation. The yearly recharge in the Great Bend Prairie ranged from 0 to 177 mm with a mean of 56 mm. Most of the recharge events occur during the months of April, May, and June, which coincide with the months of highest precipitation in the region. A multiple regression analysis revealed that the most influential variables affecting recharge are, in order of decreasing importance, total annual precipitation average maximum soil-profile water storage during the spring months, average shallowest depth to water table during the same period, and spring rainfall rate. Classification methods, whereby relatively homogeneous hydrologic-unit areas based on the four recharge-affecting variables are identified, were combined with a Geographic Information Systems (ARC/INFO) overlay analysis to derive an area-wide map of differing recharge regions. This recharge zonation is in excellent agreement with the field-site recharge values. The resulting area-weighted average annual recharge for the region is 36 mm. ?? 1992.
O. V. Barron
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.
Full Text Available The mean annual recharge of Al-Khazir Gomal Basin was estimated as a basis for decision makers regarding the renewability and sustainability of groundwater. For this purpose, two approaches were used: hydrograph analysis and water table fluctuation (WTF. The long-term mean daily stream-flow records of Al-Khazir River (1969–1981 were used to estimate groundwater discharge by base-flow hydrograph separation and displacement recession curve methods. Four base-flow separation methods were used; one is the graphical separation method, and three are automated separation methods included in the web-based Hydrograph Analysis Tool. The annual recharge estimated by WTF was 111.6 mm/y, and the average annual recharge estimated by the four base-flow separation methods was 125.8 mm/y. Estimating recharge by the water table fluctuation method does not incorporate spatial variability contained in the whole watershed, because the specific yield did not represent the entire basin. However, the hydrograph analysis method can give a comprehensive estimation of the net integrated recharge for the entire watershed, which includes different recharge mechanisms. The displacement recession curve method deviates a lot (>30 mm/y from the other methods, which indicates that this method may not be suitable to apply in such large watersheds.
Leterme, B; Mallants, D; Jacques, D
...; 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...
Tillman, Fred D; Gangopadhyay, Subhrendu; Pruitt, Tom
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...
Hartmann, Andreas; Gleeson, Tom; Wagener, Thorsten
Our environment is heterogeneous. In hydrological sciences, the heterogeneity of subsurface properties, such as hydraulic conductivities or porosities, exerts an important control on water balance. This notably includes groundwater recharge, which is an important variable for efficient and sustainable groundwater resources management. Current large-scale hydrological models do not adequately consider this subsurface heterogeneity. Here we show that regions with strong subsurface heterogeneity have enhanced present and future recharge rates due to a different sensitivity of recharge to climate variability compared with regions with homogeneous subsurface properties. Our study domain comprises the carbonate rock regions of Europe, Northern Africa, and the Middle East, which cover ∼25% of the total land area. We compare the simulations of two large-scale hydrological models, one of them accounting for subsurface heterogeneity. Carbonate rock regions strongly exhibit “karstification,” which is known to produce particularly strong subsurface heterogeneity. Aquifers from these regions contribute up to half of the drinking water supply for some European countries. Our results suggest that water management for these regions cannot rely on most of the presently available projections of groundwater recharge because spatially variable storages and spatial concentration of recharge result in actual recharge rates that are up to four times larger for present conditions and changes up to five times larger for potential future conditions than previously estimated. These differences in recharge rates for strongly heterogeneous regions suggest a need for groundwater management strategies that are adapted to the fast transit of water from the surface to the aquifers. PMID:28242703
de Vries, J.J.; Simmers, I.
Since the mid-1980s, a relative explosion of groundwater-recharge studies has been reported in the literature. It is therefore relevant to assess what is now known and to offer further guidance to practitioners involved in water-resource development. The paper summarizes current understanding of
Robert R. Ziemer
The depletion of soil moisture within the surface 7 m by a mixed conifer forest in the Sierra Nevada was measured by the neutron method every 2 weeks during 5 consecutive summers. Soil moisture recharge was measured periodically during the intervening winters. Groundwater fluctuations within the surface 17 m were continuously recorded during the same period.
Apr 13, 2012 ... 4School of the Environment, Flinders University, GPO Box 2100, Adelaide SA 5001, Australia. ABSTRACT. Land use ... images from 1984, 1992, 2002, and 2008, and to predict the impact of these land use changes on groundwater recharge. For .... Depending on climate, vegetation is a strong determining ...
Land use change is a major factor influencing catchment hydrology and groundwater resources. In South ... To reduce water loss due to evapotranspiration, non-native hill slope vegetation upstream of the Berg River Dam was cut down. It was hypothesised that recharge has been increased due to this change in vegetation.
... for the estimation of groundwater recharge through surface drains for both free flow as well as detained flow conditions. The Dupuit-Forchheimmer equation is solved using the Crank-Nicolson central finite difference scheme, to obtain the mound height matrix. The Gaussian elimination method was used to solve the matrix ...
Department of Forest Sciences, Research Institute for Agriculture & Life Sciences, College of Agriculture and. Life Sciences, Seoul National University, San 56-1, Sillim-dong, Gwanak-gu, Seoul, 151-921, Korea. ∗ e-mail: email@example.com. Groundwater recharge and base flow using different investigated methods are ...
Prada, Susana; Cruz, J. Virgílio; Figueira, Celso
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
Wang, Lei; O Dochartaigh, Brighid; MacDonald, David
This report reviews the available literature on groundwater recharge and groundwater resource assessment in Africa. The purpose of this review is to identify estimates of groundwater recharge that have been undertaken either in Africa, or outside Africa but in similar environments and climates to those found in Africa. The first part of the report highlights the importance of groundwater recharge modelling to the study of climate change impacts on groundwater resources in Africa. Section 2...
Johnson, Adam G.
per day, which is 50 percent of mean annual rainfall, and is 42 percent greater than the recharge estimate of Camp, Dresser & McKee Inc. (1982). For the northern aquifer sectors defined in Mink (1991), which encompass most of the northern half of the island, mean annual baseline recharge computed in this study is 238.0 million gallons per day, which is 51 percent of mean annual rainfall, and is about 6 percent lower than the recharge estimate of Mink (1991). For the drought simulation performed in this study, recharge for the entire island is 259.3 million gallons per day, which is 34 percent lower than recharge computed for baseline conditions. For all aquifer sectors defined by Mink (1991), total recharge during drought conditions is 32 percent lower than mean baseline recharge. For the future land-cover water-budget simulation, which represents potential land-cover changes owing to the military relocation and population growth, estimated recharge for the entire island is nearly equal to the baseline recharge estimate that was based on 2004 land cover. Using the water-budget model, estimated recharge in the northern half of the island is most sensitive to crop coefficients and net precipitation rates—two of the water-budget parameters used in the estimation of total evapotranspiration. Estimated recharge in the southern half of the island is most sensitive to crop coefficients, net precipitation rate, and runoff-to-rainfall ratios. During March 2010 to May 2011, bulk-deposition samples from five rainfall stations on Guam were collected and analyzed for chloride. Additionally, samples from five groundwater sites were collected and analyzed for chloride. Results were used to estimate groundwater recharge using the chloride mass-balance method. Recharge estimates using this method at three bulk-deposition stations on the northern limestone plateau range from about 25 to 48 percent of rainfall. These recharge estimates are similar to the estimate of Ayers (1981) who
Thomas, Abraham; Tellam, John
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
Vaughn, J.M.; Landry, E.F.
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.
Smerdon, Brian D.
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.
While most groundwater recharge estimation methods give reasonable long-term annual average estimates very few if any methods offer guidance on monthly recharge. In crystalline basement aquifers (CBAs) the problem is compounded by the high seasonal, intra-annual and inter-annual variability. The chloride mass balance (CMB), the daily catchment water balance (WB) and the water table fluctuation (WTF) groundwater recharge estimation methods have been used to estimate groundwater recharge in a s...
Stonestrom, David A.; Prudic, David E.; Walvoord, Michelle Ann; Abraham, Jared D.; Stewart-Deaker, Amy E.; Glancy, Patrick A.; Constantz, Jim; Laczniak, Randell J.; Andraski, Brian J.
The Amargosa River is an approximately 300-kilometer long regional drainage connecting the northern highlands on the Nevada Test Site in Nye County, Nev., to the floor of Death Valley in Inyo County, Calif. Streamflow analysis indicates that the Amargosa Desert portion of the river is dry more than 98 percent of the time. Infiltration losses during ephemeral flows of the Amargosa River and Fortymile Wash provide the main sources of ground-water recharge on the desert-basin floor. The primary use of ground water is for irrigated agriculture. The current study examined ground-water recharge from ephemeral flows in the Amargosa River by using streamflow data and environmental tracers. The USGS streamflow-gaging station at Beatty, Nev., provided high-frequency data on base flow and storm runoff entering the basin during water years 1998?2001. Discharge into the basin during the four-year period totaled 3.03 million cubic meters, three quarters of which was base flow. Streambed temperature anomalies indicated the distribution of ephemeral flows and infiltration losses within the basin. Major storms that produced regional flow during the four-year period occurred in February 1998, during a strong El Ni?o that more than doubled annual precipitation, and in July 1999. The study also quantified recharge beneath undisturbed native vegetation and irrigation return flow beneath irrigated fields. Vertical profiles of water potential and environmental tracers in the unsaturated zone provided estimates of recharge beneath the river channel (0.04?0.09 meter per year) and irrigated fields (0.1?0.5 meter per year). Chloride mass-balance estimates indicate that 12?15 percent of channel infiltration becomes ground-water recharge, together with 9?22 percent of infiltrated irrigation. Profiles of potential and chloride beneath the dominant desert-shrub vegetation suggest that ground-water recharge has been negligible throughout most of the basin since at least the early Holocene
Li, Zhen; Li, Miao; Liu, Xiang; Ma, Yeping; Wu, Miaomiao
Groundwater recharge using reclaimed water is considered a promising method to alleviate groundwater depletion, especially in arid areas. Traditional water treatment systems are inefficient to remove all the types of contaminants that would pose risks to groundwater, so it is crucial to establish a priority list of organic compounds (OCs) that deserve the preferential treatment. In this study, a comprehensive ranking system was developed to determine the list and then applied to China. 151 OCs, for which occurrence data in the wastewater treatment plants were available, were selected as candidate OCs. Based on their occurrence, exposure potential and ecological effects, two different rankings of OCs were established respectively for groundwater recharge by surface infiltration and direct aquifer injection. Thirty-four OCs were regarded as having no risks while the remaining 117 OCs were divided into three groups: high, moderate and low priority OCs. Regardless of the recharge way, nonylphenol, erythromycin and ibuprofen were the highest priority OCs; their removal should be prioritized. Also the database should be updated as detecting technology is developed. Copyright © 2014 Elsevier B.V. All rights reserved.
Brian F. Thomas
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.
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)
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.
Anuraga, T.S.K.; Ruiz, L.; Mohan Kumar, M.S.; Sekhar, M.; Leijnse, A.
Groundwater recharge is a key factor in water balance studies, especially in semi-arid areas. In India, the Groundwater Evaluation Committee recommends the use of the ¿water table rise method¿ to evaluate recharge. However, this method does not account for spatial variation of recharge, which can be
Selle, B.; Shakked, N.; Rink, K.; Kolditz, O.
The long-term average groundwater recharge typically varies greatly in space due to differences in climate, soil, landuse, topography and groundwater levels. Long-term average recharge is a key input to steady- state groundwater models. This type of models is frequently used to determine the long-term safe yield to aquifer systems and to predict the fate of human-derived contaminants in capture zones of groundwater production wells. An accurate quantification of the spatial distribution of recharge is therefore important but difficult to achieve as it cannot be directly measured at regional scales. Several methods have been applied to indirectly estimate the spatial distribution of long-term average groundwater recharge including spatially distributed hydrological modelling and the regionalisation of catchment scale recharge estimated from long-term average baseflows. In the context of a groundwater model, it is difficult to evaluate the reliability of these recharge maps if groundwater levels are the only data set available for model calibration. Concentrations of environmental tracers measured at groundwater wells can be used to interpret the apparent groundwater age, which in turn is significantly influenced by the magnitude and spatial distribution of recharge contributing groundwater to the well. Thus, the apparent groundwater age at wells may be useful to assess the reliability of maps on long term average groundwater recharge. To test this hypothesis, a steady-state groundwater model was set up for a 180 km2 area in SW Germany, which is extensively used for groundwater production from a confined limestone aquifer. We tested three maps of long-term average recharge that were all computed using different methods. For each recharge map, the steady-state groundwater model was calibrated against water levels and mean groundwater ages were calculated for groundwater production wells from particle tracking methods. These computed groundwater ages were subsequently
Full Text Available An analysis of the stable isotopes and the major ions in the surface water and groundwater in the Leizhou Peninsula was performed to identify the sources and recharge mechanisms of the groundwater. In this study, 70 water samples were collected from rivers, a lake, and pumping wells. The surface water was considered to have a lower salinity than the groundwater in the region of study. The regression equations for δD and δ18O for the surface water and the groundwater are similar to those for precipitation, indicating meteoric origins. The δD and δ18O levels in the groundwater ranged from −60‰; to −25‰; and −8.6‰; to −2.5‰, respectively, and were lower than the stable isotope levels from the winter and spring precipitation. The groundwater in the southern area was classified as the Ca2+-Mg2+-HCO3--type, whereas the groundwater in the northern area included three types (Na+-Cl−-type, Ca2+-Mg2+-HCO3--type, and Ca2+-Mg2+-Cl−-type, indicating rapid and frequent water-rock exchange in the region. A reasonable conclusion is that the groundwater chemistry is dominated by rock weathering and rainwater of local origin, which are influenced by seawater carried by the Asian monsoon.
Tillman, Fred; Gangopadhyay, Subhrendu; Pruitt, Tom
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.
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.
Nolan, Bernard T.; Baehr, Arthur L.; Kauffman, Leon J.
Point estimates of groundwater recharge at 48 sediment-coring locations vary substantially (−18.5–1840 cm yr−1) in a 930-km2 area of southern New Jersey. Darcian estimates of steady, long-term recharge made at depth in the unsaturated zone were estimated using pedotransfer functions of soil texture and interpolated (mapped) with nonparametric methods to assess aquifer vulnerability in the area. The probability of exceeding the median recharge (29.1 cm yr−1) is low in the southwestern and northeastern portions of the study area and high in the eastern and southeastern portions. Estimated recharge is inversely related to measured percentage clay and positively related to the percentage of well-drained soils near wells. Spatial patterns of recharge estimates, exceedance probabilities, and clay content indicate that sediment texture controls recharge in the study area. Relations with land elevation and a topographic wetness index were statistically insignificant. Nitrate concentration and atrazine (6-chloro-N 2-ethyl-N 4-isopropyl-1,3,5-triazine-2,4-diamine) percentage detection in samples of shallow groundwater (typically 29.1 cm yr−1) in agricultural and urban areas. Differences between high and low recharge sites in these areas are highly significant for NO3 concentration, but not for atrazine concentration.
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.
Acharya, Gayatri; Barbier, Edward B.
This study applies a production function approach to value the groundwater recharge function of the Hadejia-Nguru wetlands in northern Nigeria. The groundwater recharge function supports dry season agricultural production which is dependent on groundwater abstraction for irrigation. Using survey data this paper first carries out an economic valuation of agricultural production, per hectare of irrigated land. We then value the recharge function as an environmental input into the dry season agr...
Z. Zomlot; B. Verbeiren; M. Huysmans; Batelaan, O.
Study focus: Groundwater is of strategic importance. The accurate estimation of groundwater recharge and assessing the fundamental controlling factors are therefore of utmost importance to protect groundwater systems. We used the spatially-distributed water-balance model WetSpass to estimate long-term average recharge in Flanders. We validated recharge rates with base flow estimates of 67 daily stream flow records using the hydrograph analyses. To this end we performed principal component ana...
B. Leterme; D. Mallants; Jacques, D.
The impact of climate change on groundwater recharge is simulated using climatic analogue stations, i.e. stations presently under climatic conditions corresponding to a given 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 estimating groundwater recharge for the next millennia. Groundwater recharge was simulated using the Richard...
Oliveira, P. T. S.; Leite, M.; Mattos, T.; Wendland, E.; Nearing, M. A.
Since 2014, several cities of southeastern Brazil have grappled with their worst drought in nearly 80 years. To improve water availability in this region, the Brazilian government has studied the possibility of increasing groundwater use, mainly in the Guarani Aquifer System (GAS), the largest (~1.2 million km2) transnational boundary groundwater reservoir in South America. Approximately one half of the outcrop areas of the GAS are located in the Cerrado biome, the main agricultural expansion region in Brazil. Large areas of Cerrado vegetation have been converted into farmland in recent years; however, little attention has been paid to the consequences of this land cover and land use change on groundwater recharge. In this study we assessed groundwater recharge in different physiognomies of the Cerrado located in an outcrop area of the GAS. Water table fluctuations were measured from October 2011 through August 2013, by 64 monitoring wells distributed on five physiognomies of the undisturbed Cerrado. We used 20 (2.2±0.3 m), 20 (4.3±1.4 m), 14 (4.7±1.9 m), 9 (6.2±0.7 m), and 1 (42 m) monitoring wells (and average depth of wells) for "campo limpo" (cerrado grassland), "campo sujo" (shrub cerrado), "campo cerrado" (shrub cerrado), "cerrado sensu stricto" (wooded cerrado), and "cerrado sensu stricto denso" (cerrado woodland), respectively. Recharge was computed for each well using the Water Table Fluctuation method. The measured precipitation for hydrological years 2011-12 and 2012-13 were 1247 mm and 1194 mm, respectively. We found values of average annual recharge of 363 mm, 354 mm, 324 mm, and 315 mm for "campo limpo", "campo sujo","campo cerrado", and "cerrado sensu stricto", respectively. We did not find changes in the water table level in the one well located in the "cerrado sensu stricto denso". The water table in this well was 35 m deep; therefore, the amount of water that eventually reached the saturated zone was not enough to cause a rapid change in the
Full Text Available Estimating groundwater recharge is an important part of the water resources evaluation. In spite of the numerous existing methods it continues to be not easy value to quantify. This is due to its dependence on many meteorological, hydrogeological, soil type and cover conditions and the impossibility for direct measurement. Employment of hydrological models in fact directly calculates the influence of the above cited natural factors. The Community Land Model (CLM3 being loaded with all land featuring data in global scale, including an adequate soil filtration process simulation by the Richards equation, together with the possibility for input of NCEP/NCAR Reanalyses database, featuring the meteorological effect, gives an opportunity to avoid to great extent the difficulties in groundwater (GW recharge estimation. The paper presents the results from an experiment concerning GW recharge monthly estimation during 2013, worked out for the Kamchia river watershed in Bulgaria. The computed monthly and annual values are presented on GIS maps and are compared with existing assessments made by other methods. It is proved the good approach and the applicability of the method.
Zlotnik, Vitaly A; Kacimov, Anvar; Al-Maktoumi, Ali
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.
McBurnett, Lauren R; Holt, Nathan T; Alum, Absar; Abbaszadegan, Morteza
This study elucidates the potential risk posed by Legionella during aquifer recharge practices. Experiments were conducted using pilot-scale column simulating infiltration of bacterial surrogate and pathogen, E. coli and Legionella pneumophila, under central Arizona recharge basin conditions. A column was packed with a loamy sand media collected from a recharge basin and was fitted with six sampling ports at soil depths of 15, 30, 60, 92, 122cm and acclimated for a month with tertiary treated wastewater. Transport of Legionella appeared to be delayed compared to E. coli. The breakthrough of E. coli and Legionella at 122cm depth occurred at 3 and 24h, respectively. Slow transport of Legionella is consistent with its pleomorphic nature and variation in size and shape under low nutrient conditions. Legionella persisted for a longer time in the column, but at lower concentrations. Given the novel results of this study, the transport of Legionella into groundwater aquifers can occur through engineering recharge basin conditions creating a potential public health risk. Copyright © 2017. Published by Elsevier B.V.
Larsen, Flemming; Owen, R.; Dahlin, T.
of the mid-Zambezi basin (Fig. 1). The potential for groundwater abstraction seems to be huge. The key issues in this part of the study are the extent of the recharge area and the recharge rates. The direct recharge area has previously been considered to be the area of outcrop of Karoo Forest sandstone...... support this extension of the recharge area to include a large area below the fractured basalt. CO2 gas pressures, calculated with the code PHREEQC using field measurements of pH and alkalinity, show that below the fractured basalt the groundwater is an open system in contact with atmospheric CO2. The 14C...... and nitrate concentrations in this groundwater also indicate that recent infiltration takes place. The chloride contents of the rainfall and the groundwater in the recharge area have been measured to calculate direct recharge from rainfall. These data indicate that the direct recharge is in the range of 10...
Zhang, Zhiqiang; Li, Min; Si, Bingcheng; Feng, Hao
Unlike recharge in shallow rooted ecosystems, estimating the groundwater recharge beneath deep rooted plants that absorb water from deep soil remains difficult. The purpose of this research is to develop an approach to estimate the groundwater recharge beneath deep-rooted vegetation by combining water mass balance and chloride mass balance (CMB) and to quantify how the conversion of shallow-rooted cropland to deep-rooted apple orchards changes groundwater recharge. The proposed groundwater recharge rate under deep-rooted vegetation in this study is the difference between the groundwater recharge rate in a cropland (obtained using CMB) and the mean annual soil water storage deficit beneath an adjacent deep-rooted vegetation. The results show that the conversion from cropland (shallow-rooted) to apple orchard (deep-rooted) decreased soil water storage by 776, 1106, and 1117mm, corresponding to 19, 20, and 26-year-old apple orchards, respectively. Groundwater recharge beneath cropland, on average, was 58mmyr -1 , which amounts to 10% of the average annual precipitation. Groundwater recharge beneath the apple orchards were variable, but all being <3% of the average annual precipitation. The conversion of cropland to apple orchards lead to a substantial decrease in groundwater recharge, potentially threatening the sustainability of the land use change. Copyright © 2017 Elsevier B.V. All rights reserved.
Keywords: remote sensing, GIS, water balance, groundwater, net groundwater use, recharge, water management, Rechna Doab, Pakistan.
Over-exploitation of groundwater resources threatens the future of irrigated agriculture, especially in the arid and semi-arid regions of the world. In
Aryanto, Daniel Eko; Hardiman, Gagoek
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.
Zhang, Wenjing; Huan, Ying; Yu, Xipeng; Liu, Dan; Zhou, Jingjing
Taking an artificial groundwater recharge site in Shanghai, China as an example, this study employed a combination of laboratory experiment and numerical modeling to investigate the transport and transformation of major solutes, as well as the mechanism of associated water-rock interactions in groundwater during artificial groundwater recharge. The results revealed that: (1) Major ions in groundwater were mainly affected by mixing, ion exchanging (Ca(2+), Mg(2+), Na(+), K(+)), as well as dissolution of Calcite, Dolomite. Dissolution of carbonate minerals was not entirely dependent on the pattern of groundwater recharge, the reactivity of the source water itself as indicated by the sub-saturation with respect to the carbonate minerals is the primary factor. (2) Elemental dissolution of As, Cr and Fe occurred in aquifer was due to the transformation of subsurface environment from anaerobic to aerobic systems. Different to bank filtration recharge or pond recharge, the concentration of Fe near the recharge point was mainly controlled by oxidation dissolution of Siderite, which was followed by a release of As, Cr into groundwater. (3) Field modeling results revealed that the hydro chemical type of groundwater gradually changed from the initial Cl-HCO3-Na type to the Cl-HCO3-Na-Ca type during the recharge process, and its impact radius would reach roughly 800 m in one year. It indicated that the recharge pressure (approx. 0.45 Mpa) would enlarge the impact radius under deep well recharge conditions. According to different recharge modes, longer groundwater resident time will associate with minerals' fully reactions. Although the concentrations of major ions were changing during the artificial recharge process, it did not pose a negative impact on the environmental quality of groundwater. The result of trace elements indicated that controlling the environment factors (especially Eh, DO, flow rate) during the recharge was effective to reduce the potential threats to
Darko, Philip K.
The Sacramento soil moisture-accounting model has been used to simulate the discharges of a major catchment (Pra river basin) in southern Ghana. Through the simulation it was possible to assess the temporal variability of evapotranspiratio, base flow proportions and groundwater in storage, as well as the average groundwater recharge to the weathered aquifers. Groundwater recharge was estimated by considering the measured discharge of groundwater across the boundary of the basin over periods o...
Tsai, Jui-Pin; Chang, Liang-Cheng; Chang, Ping-Yu; Lin, Yuan-Chien; Chen, You-Cheng; Wu, Meng-Ting; Yu, Hwa-Lung
The delineation of groundwater recharge zones is crucial for the conservation of groundwater quality and quantity. To objectively estimate groundwater recharge zones, many field surveys are required that are costly in both time and money. To facilitate the assessment of recharge zones with high efficiency and low expense, this study proposes a 'fast-filter' approach based on empirical orthogonal function analysis and applies it in a synthetic case study and to Taiwan's Yilan Plain. In the synthetic case study, we demonstrate that the proposed method can effectively identify the recharge area by considering the head variations driven by rainfall recharge. For the case of Yilan Plain application, the field investigations (i.e., collected wellbore logs and electrical resistivity tomography [ERT] surveys) and a groundwater simulation model support the recharge zones estimated by the proposed method. The study results show that within the estimated recharge zone, all of the collected wellbore logs consist of coarse grains, and thick and continuous high resistivity zones were shown in the ERT profile images. Moreover, the groundwater model indicates that the recharge within the estimated recharge zone is 57.6% of the total recharge despite that the area of the estimated zone is only 26.8% of the study area. Therefore, the proposed method is shown to delineate recharge zones at low cost.
Groundwater recharge estimation in crystalline basement aquifers in semi-arid tropical areas is best estimated at monthly time scales as this best captures the dynamics of recharge processes in these areas. Whilst it is standard practice to use at least two methods to estimate the recharge it may be
Schmidt, Calla M; Fisher, Andrew T; Racz, Andrew J; Lockwood, Brian S; Huertos, Marc Los
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.
Balke, Klaus-Dieter; Zhu, Yan
Worldwide, several regions suffer from water scarcity and contamination. The infiltration and subsurface storage of rain and river water can reduce water stress. Artificial groundwater recharge, possibly combined with bank filtration, plant purification and/or the use of subsurface dams and artificial aquifers, is especially advantageous in areas where layers of gravel and sand exist below the earth's surface. Artificial infiltration of surface water into the uppermost aquifer has qualitative and quantitative advantages. The contamination of infiltrated river water will be reduced by natural attenuation. Clay minerals, iron hydroxide and humic matter as well as microorganisms located in the subsurface have high decontamination capacities. By this, a final water treatment, if necessary, becomes much easier and cheaper. The quantitative effect concerns the seasonally changing river discharge that influences the possibility of water extraction for drinking water purposes. Such changes can be equalised by seasonally adapted infiltration/extraction of water in/out of the aquifer according to the river discharge and the water need. This method enables a continuous water supply over the whole year. Generally, artificially recharged groundwater is better protected against pollution than surface water, and the delimitation of water protection zones makes it even more save.
Yang, Xiaolin; Chen, Yuanquan; Pacenka, Steven; Gao, Wangsheng; Zhang, Min; Sui, Peng; Steenhuis, Tammo S
Water tables are dropping by approximately one meter annually throughout the North China Plain mainly due to water withdrawals for irrigating winter wheat year after year. In order to examine whether the drawdown can be reduced we calculate the net water use for an 11 year field experiment from 2003 to 2013 where six irrigated crops (winter wheat, summer maize, cotton, peanuts, sweet potato, ryegrass) were grown in different crop rotations in the North China Plain. As part of this experiment moisture contents were measured each at 20 cm intervals in the top 1.8 m. Recharge and net water use were calculated based on these moisture measurement. Results showed that winter wheat and ryegrass had the least recharge with an average of 27 mm/year and 39 mm/year, respectively; cotton had the most recharge with an average of 211 mm/year) followed by peanuts with 118 mm/year, sweet potato with 76 mm/year, and summer maize with 44 mm/year. Recharge depended on the amount of irrigation water pumped from the aquifer and was therefore a poor indicator of future groundwater decline. Instead net water use (recharge minus irrigation) was found to be a good indicator for the decline of the water table. The smallest amount of net (ground water) used was cotton with an average of 14 mm/year, followed by peanut with 32 mm/year, summer maize with 71 mm/year, sweet potato with 74 mm/year. Winter wheat and ryegrass had the greatest net water use with the average of 198 mm/year and 111 mm/year, respectively. Our calculations showed that any single crop would use less water than the prevalent winter wheat summer maize rotation. This growing one crop instead of two will reduce the decline of groundwater and in some rain rich years increase the ground water level, but will result in less income for the farmers.
Oden, Timothy D.; Delin, Geoffrey N.
Simply stated, groundwater recharge is the addition of water to the groundwater system. Most of the water that is potentially available for recharging the groundwater system in Montgomery and adjacent counties in southeast Texas moves relatively rapidly from land surface to surface-water bodies and sustains streamflow, lake levels, and wetlands. Recharge in southeast Texas is generally balanced by evapotranspiration, discharge to surface waters, and the downward movement of water into deeper parts of the groundwater system; however, this balance can be altered locally by groundwater withdrawals, impervious surfaces, land use, precipitation variability, or climate, resulting in increased or decreased rates of recharge. Recharge rates were compared to the 1971–2000 normal annual precipitation measured Cooperative Weather Station 411956, Conroe, Tex.
Gemitzi, Alexandra; Ajami, Hoori; Richnow, Hans-Hermann
Groundwater recharge is one of main components of the water budget that is difficult to quantify due to complexity of recharge processes and limited observations. In the present work a simple regression equation for monthly groundwater recharge estimation is developed by relating simulated recharge from a calibrated Soil and Water Assessment tool (SWAT) model to effective precipitation. Monthly groundwater recharge and actual evapotranspiration (AET) were computed by applying a calibrated (SWAT) model for a ten year period (2005-2015) in Vosvozis river basin in NE Greece. SWAT actual evapotranspiration (AET) results were compared to remotely sensed AET values from the MODerate Resolution Imaging Spectroradiometer (MODIS), indicating the integrity of the modeling process. Water isotopes of 2H and 18O, originally presented herein, were used to infer recharge resources in the basin and provided additional evidence of the applicability of the developed formula. Results showed that the developed recharge estimation method can be effectively applied using MODIS evapotranspiration data, without having to adhere to numerical modeling which is many times constrained by the lack of available data especially in poorly gauged basins. Future trends of groundwater recharge up to 2100 using an ensemble of five downscaled climate change projections indicated that annual recharge will increase up to the middle of the present century and gradually decrease thereafter. However, the predicted magnitude is highly variable depending on the Global Climate Model (GCM) used. While winter recharge will likely increase in the future, summer recharge is expected to decrease as a result of temperature rise in the future.
Dahlke, H. E.; Kocis, T. N.; Brown, A.
Groundwater banking, the intentional recharge of groundwater from surface water for storage and recovery, is an important conjunctive use strategy for water management in California (CA). A largely unexplored approach to groundwater banking, agricultural groundwater banking (ag-GB), utilizes flood flows and agricultural lands (alfalfa/pasture) for recharging groundwater. Understanding soil suitability for ag-GB, crop health and flooding tolerance, leaching of soil nitrate and salts, the availability of surface water for recharge, and the economic costs and benefits of ag-GB is fundamental to assessing the feasibility of local-scale implementation of ag-GB. The study presented here considers both the availability of excess streamflow (e.g., the magnitude, frequency, timing, and duration of winter flood flow) for ag-GB and the risks and benefits associated with using alfalfa fields as spreading grounds for ag-GB. The availability of surface water for winter (Nov to Apr) ag-GB were estimated based on daily streamflow records for 93 stream gauges within the Central Valley, CA. Analysis focused on high-magnitude (>90thpercentile) flows because most lower flows are likely legally allocated in CA. Results based >50 years of data indicate that an average winter/spring (Nov. - Apr.) in the Sacramento River Basin could provide 7 million acre-feet (AF) (8.6 km3) of water for ag-GB from flows above the 90th percentile. These flows originate from few storm events (5-7 events) and occur on average for 25-30 days between November and April. Wintertime on-farm recharge experiments were conducted on a 9-yr old, 15-acre alfalfa field in the Scott Valley, CA, where 135 AF and 107 AF of water were recharged during the winters of 2015 and 2016, respectively. Biomass data collected indicates that pulsed application of 6-10 ft of water on dormant alfalfa results in minimal yield loss (0.5 ton/acre reduction), short-duration saturated conditions in the root-zone, and high recharge
Jackson, Christopher; Bianchi, Marco
Estimation of groundwater recharge has underpinned a wide variety of groundwater resource and quality assessments within the UK at a range of scales. For example, there are many studies that have quantified time‑varying recharge rates in order to model the transport of diffuse and point-source pollutants from the land surface, through groundwater systems to receptors such as rivers and abstraction boreholes (e.g. Stuart et al., 2006; Wilby et al., 2006; Jackson et al., 2007; Cuthbert et al., ...
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.
Singh, Amanpreet; Panda, S N; Kumar, K S; Sharma, Chandra Shekhar
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.
Dripps, W.R.; Bradbury, K.R.
Recharge varies spatially and temporally as it depends on a wide variety of factors (e.g. vegetation, precipitation, climate, topography, geology, and soil type), making it one of the most difficult, complex, and uncertain hydrologic parameters to quantify. Despite its inherent variability, groundwater modellers, planners, and policy makers often ignore recharge variability and assume a single average recharge value for an entire watershed. Relatively few attempts have been made to quantify or incorporate spatial and temporal recharge variability into water resource planning or groundwater modelling efforts. In this study, a simple, daily soil-water balance model was developed and used to estimate the spatial and temporal distribution of groundwater recharge of the Trout Lake basin of northern Wisconsin for 1996-2000 as a means to quantify recharge variability. For the 5 years of study, annual recharge varied spatially by as much as 18 cm across the basin; vegetation was the predominant control on this variability. Recharge also varied temporally with a threefold annual difference over the 5-year period. Intra-annually, recharge was limited to a few isolated events each year and exhibited a distinct seasonal pattern. The results suggest that ignoring recharge variability may not only be inappropriate, but also, depending on the application, may invalidate model results and predictions for regional and local water budget calculations, water resource management, nutrient cycling, and contaminant transport studies. Recharge is spatially and temporally variable, and should be modelled as such. Copyright ?? 2009 John Wiley & Sons, Ltd.
Patel, Tanya; Hindshaw, Ruth; Singer, Michael
Water is a vital resource in any agricultural watershed, yet in the arid western United States farming practices threaten the quality and availability of groundwater. This is a pressing concern in the San Luis Valley, southern Colorado, where agriculture comprises 30% of the local economy, and employs over half the valley population. Although 54 % of the water used for irrigation is surface water, farmers do not usually apply this water directly to their fields. Instead, the water is often diverted into pits which recharge the aquifer, and the water is subsequently pumped during the following irrigation season. The Rio Grande Water Conservation District recognises that recharge to the unconfined aquifer has been outpaced by commercial irrigation for at least four decades, resulting in a decline in groundwater levels. Recycled irrigation water, and leakage from unlined canals now represent the greatest recharge contribution to the unconfined aquifer in this region. This makes the shallow groundwater particularly susceptible to agricultural contamination. The purpose of this study is to assess groundwater contamination in the unconfined and upper confined aquifers of the San Luis Valley, which are the most susceptible to contamination due to their close proximity to the surface. Although concentrations of potentially harmful contaminants from agricultural runoff are regularly monitored, the large spatial and temporal fluctuations in values make it difficult to determine long-term trends. We have analysed δ18O, δ2H and major-ion chemistry of 57 groundwater, stream and precipitation samples, collected in June 2014, and interpreted them alongside regional stream flow data and groundwater levels. This will allow us to study the seasonality and locality of groundwater recharge to provide greater insight into the watershed's potential for pollution. A groundwater vulnerability assessment was performed using the model DRASTIC (Depth to water, Recharge, Aquifer media, Soil
Westenbroek, S.M.; Kelson, V.A.; Dripps, W.R.; Hunt, R.J.; Bradbury, K.R.
A Soil-Water-Balance (SWB) computer code has been developed to calculate spatial and temporal variations in groundwater recharge. The SWB model calculates recharge by use of commonly available geographic information system (GIS) data layers in combination with tabular climatological data. The code is based on a modified Thornthwaite-Mather soil-water-balance approach, with components of the soil-water balance calculated at a daily timestep. Recharge calculations are made on a rectangular grid of computational elements that may be easily imported into a regional groundwater-flow model. Recharge estimates calculated by the code may be output as daily, monthly, or annual values.
Melki, Achraf; Abdollahi, Khodayar; Fatahi, Rouhallah; Abida, Habib
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.
Li, Zhi; Chen, Xi; Liu, Wenzhao; Si, Bingcheng
Studying the groundwater recharge mechanism in regions with thick unsaturated zone can greatly improve our understanding of hydrological processes since these regions have complex groundwater processes. This study attempted to discuss the groundwater recharge in a region covered by loess over 130m deep in China's Loess Plateau. The water stable isotope, tritium and chloride in precipitation, groundwater and soil water were determined and used as inputs of mass balance methods. The tracer technique is found to be applicable and effective this region with thick unsaturated zone. The groundwater originates from rapid precipitation infiltration through some fast flow paths. The total recharge is likely to be 107±55mmyr -1 accounting for 19±10% of average annual precipitation, while the recharge from preferential flow accounts for 87±4% of the total recharge. The identified recharge mechanism has important implication to groundwater management and recharge modeling for regions covered by thick loess. Copyright © 2017 Elsevier B.V. All rights reserved.
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.
Tompson, Andrew F. B.; Carle, Steven F.; Rosenberg, Nina D.; Maxwell, Reed M.
The increased use of reclaimed water for artificial groundwater recharge purposes has led to concerns about future groundwater quality, particularly as it relates to the introduction of new organic and inorganic contaminants into the subsurface. Here we review the development and initial application of a detailed numerical model of groundwater flow and migration in a region encompassing a large groundwater recharge operation in Orange County, California. The model is based upon a novel representation of geologic heterogeneity, which has long been known to influence local flow and transport behavior in the subsurface. The model and complementary series of isotopic analyses provide an improved scientific basis to understand flow paths, migration rates, and residence times of recharged groundwater, as well as to identify the source composition of water produced in wells near the recharge operation. From a management perspective these issues need to be confronted in order to respond to proposed regulatory constraints that would govern the operation of recharge facilities and nearby production wells. While model calibration is greatly aided by isotopic source and residence time analyses, the model also provides unique insights on the interpretation of isotopic data themselves. Isotopic estimates of groundwater age help discriminate between several equally acceptable simulations calibrated to head data only. However, the results also suggest that groundwater reaching a well spans a wide-ranging distribution of age, demonstrating the importance of geologic heterogeneity in affecting flow paths, mixing, and residence times in the vicinity of recharge basins and wells.
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
Wilson, Scott; Wöhling, Thomas; Davidson, Peter
The braided Wairau River is the main source of recharge to the Wairau gravel aquifer in Marlborough, New Zealand. Flow measurements indicate a 6 to 15 m3/s loss as the river traverses the Wairau alluvial fan, a distance of 15 km. The hydrological processes regulating this flow loss are not well understood. Theoretically, the relationship between a river and groundwater can be considered as being hydraulically connected (gaining or losing), disconnected, or transitional (Brunner et al. 2011). A disconnected river is distinguished from a hydraulically connected river by a partially saturated zone between the river bed and the aquifer. The aim of this study is to improve our conceptual understanding of how flow losses occur, and to test a new hypothesis that much of the river is hydraulic disconnected from the aquifer. It is practically difficult to make direct observations of the saturation status beneath a river bed. However, indirect observations can be employed to characterize the nature of the river-aquifer exchange, and we have used a variety of data sources (stratigraphy, piezometric surfaces including LiDAR, temperature and radon tracers). Several lines of evidence from these data sources indicate that the dominant recharge reach of the river is hydraulically disconnected, or at least transitional in nature. This simplifies the prediction of transient flow losses, which only requires knowledge of near-surface Kz and wetted river area values. The hydraulic mechanism for a disconnected river condition is the anisotropy of the sandy gravel sequence. The braided river depositional process has formed a finely layered sequence of silt, sand and gravel lenses. This stratification, combined with clast and particle imbrication, has formed a highly anisotropic hydrogeology. Results from aquifer tests analyzed for leakage have typical Kx values of 500 m/d and Kz values of around 0.5 m/d. The large Kx/Kz ratio enables the aquifer to potentially discharge more rapidly in a
Vijai Singhal; Rohit Goyal
Accurate estimation of groundwater recharge is extremely important for propermanagement of groundwater systems. Attempts have been made by various researchers torelate impact of various parameters on groundwater recharge. In the present study, amethodology based on spatial distribution of parameters has been developed forunderstanding affect of rainfall and vegetation density on groundwater recharge.Normalized Difference Vegetation Index (NDVI) has been used as an indicative parameterfor vege...
Mair, Alan; Hagedorn, Benjamin; Tillery, Suzanne; El-Kadi, Aly I.; Westenbroek, Stephen M.; Ha, Kyoochul; Koh, Gi-Won
Estimates of groundwater recharge spatial and temporal variability are essential inputs to groundwater flow models that are used to test groundwater availability under different management and climate conditions. In this study, a soil water balance analysis was conducted to estimate groundwater recharge on the island of Jeju, Korea, for baseline, drought, and climate-land use change scenarios. The Soil Water Balance (SWB) computer code was used to compute groundwater recharge and other water balance components at a daily time step using a 100 m grid cell size for an 18-year baseline scenario (1992–2009). A 10-year drought scenario was selected from historical precipitation trends (1961–2009), while the climate-land use change scenario was developed using late 21st century climate projections and a change in urban land use. Mean annual recharge under the baseline, drought, and climate-land use scenarios was estimated at 884, 591, and 788 mm, respectively. Under the baseline scenario, mean annual recharge was within the range of previous estimates (825–959 mm) and only slightly lower than the mean of 902 mm. As a fraction of mean annual rainfall, mean annual recharge was computed as only 42% and less than previous estimates of 44–48%. The maximum historical reported annual pumping rate of 241 × 106 m3 equates to 15% of baseline recharge, which is within the range of 14–16% computed from earlier studies. The model does not include a mechanism to account for additional sources of groundwater recharge, such as fog drip, irrigation, and artificial recharge, and may also overestimate evapotranspiration losses. Consequently, the results presented in this study represent a conservative estimate of total recharge.
Visser, A.; Segal, D.; Urióstegui, S. H.; Singleton, M. J.; Moran, J. E.; Esser, B. K.
Martis Valley's groundwater basin is experiencing increasing water demand and changes in the amount and timing of snowmelt due to climate change. Groundwater is the exclusive water supply for the town of Truckee and its surrounding ski resorts and golf courses. The objective of this study was to examine seasonal variability in the aquifer recharge by analyzing supply wells for: 1) tritium and helium isotopes to determine groundwater sources and age, 2) dissolved noble gases to determine recharge temperatures and excess air concentrations and 3) stable isotopes to determine groundwater sources. Recharge temperatures were found to be similar to mean annual air temperatures at lower elevations, suggesting that most recharge is occurring at lower elevations after equilibrating in the vadose zone. Low levels of excess air found in groundwater confirm that most recharge is occurring in the valley alluvium rather than the mountain block. The mean integrated groundwater flow depth was estimated for each well from the temperature difference between recharge and discharge and the geothermal gradient. Groundwater samples contained large amounts of excess terrigenic helium, from both mantle and radiogenic sources. Terrigenic helium and tritium concentrations were used to reconstruct the mixing between the younger and older groundwater sources. Mantle helium originating from the Polaris Fault was used to trace groundwater flow directions. Higher seasonal variability was found in wells with younger groundwater and shallower flow depths, suggesting that changes in the timing and amount of recharge under warmer climate conditions will rather quickly impact at least a portion of the aquifer system in Martis Valley. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
U.S. Geological Survey, Department of the Interior — This 1-kilometer resolution raster (grid) dataset is an index of mean annual natural ground-water recharge. The dataset was created by multiplying a grid of...
Zhang, L; Dawes, W. R; Hatton, T. J; Reece, P. H; Beale, G. T. H; Packer, I
A distributed parameter ecohydrological model (TOPOG_IRM) was applied to a 1.6 km 2 pastoral catchment in southeast Australia for estimating soil moisture and groundwater recharge, for a period of 1992–1994...
Lu, Xiaohui; Jin, Menggui; van Genuchten, Martinus Th; Wang, Bingguo
Accurate estimates of groundwater recharge are essential for effective management of groundwater, especially when supplies are limited such as in many arid and semiarid areas. In the Hebei Plain, China, water shortage is increasingly restricting socioeconomic development, especially for agriculture, which heavily relies on groundwater. Human activities have greatly changed groundwater recharge there during the past several decades. To obtain better estimates of recharge in the plain, five representative sites were selected to investigate the effects of irrigation and water table depth on groundwater recharge. At each site, a one-dimensional unsaturated flow model (Hydrus-1D) was calibrated using field data of climate, soil moisture, and groundwater levels. A sensitivity analysis of evapotranspirative fluxes and various soil hydraulic parameters confirmed that fine-textured surface soils generally generate less recharge. Model calculations showed that recharge on average is about 175 mm/year in the piedmont plain to the west, and 133 mm/year in both the central alluvial and lacustrine plains and the coastal plain to the east. Temporal and spatial variations in the recharge processes were significant in response to rainfall and irrigation. Peak time-lags between infiltration (rainfall plus irrigation) and recharge were 18 to 35 days in the piedmont plain and 3 to 5 days in the central alluvial and lacustrine plains, but only 1 or 2 days in the coastal plain. This implies that different time-lags corresponding to different water table depths must be considered when estimating or modeling groundwater recharge. Copyright © 2010 The Author(s). Journal compilation © 2010 National Ground Water Association.
Stonestrom, David A.; Harrill, James R.
Ground-water recharge in the arid and semiarid southwestern United States results from the complex interplay of climate, geology, and vegetation across widely ranging spatial and temporal scales. Present-day recharge tends to be narrowly focused in time and space. Widespread water-table declines accompanied agricultural development during the twentieth century, demonstrating that sustainable ground-water supplies are not guaranteed when part of the extracted resource represents paleorecharge. Climatic controls on ground-water recharge range from seasonal cycles of summer monsoonal and winter frontal storms to multimillennial cycles of glacial and interglacial periods. Precipitation patterns reflect global-scale interactions among the oceans, atmosphere, and continents. Large-scale climatic influences associated with El Ni?o and Pacific Decadal Oscillations strongly but irregularly control weather in the study area, so that year-to-year variations in precipitation and ground-water recharge are large and difficult to predict. Proxy data indicate geologically recent periods of multidecadal droughts unlike any in the modern instrumental record. Anthropogenically induced climate change likely will reduce ground-water recharge through diminished snowpack at higher elevations, and perhaps through increased drought. Future changes in El Ni?o and monsoonal patterns, both crucial to precipitation in the study area, are highly uncertain in current models. Land-use modifications influence ground-water recharge directly through vegetation, irrigation, and impermeable area, and indirectly through climate change. High ranges bounding the study area?the San Bernadino Mountains and Sierra Nevada to the west, and the Wasatch and southern Colorado Rocky Mountains to the east?provide external geologic controls on ground-water recharge. Internal geologic controls stem from tectonic processes that led to numerous, variably connected alluvial-filled basins, exposure of extensive
In irrigated semi-arid and arid regions, accurate knowledge of groundwater recharge is important for the sustainable management of scarce water resources. The Campo de Cartagena area of southeast Spain is a semi-arid region where irrigation return flow accounts for a substantial portion of recharge....
While most groundwater recharge estimation methods give reasonable long-term annual average estimates very few if any methods offer guidance on monthly recharge. In crystalline basement aquifers (CBAs) the problem is compounded by the high seasonal, intra-annual and inter-annual variability. The
Oluseyi O. Adeleke
Full Text Available Estimation and forecast of groundwater recharge and capacities of aquifers are essential issues in water resource investigation. In the current research, groundwater recharge and the recharge coefficient were determined through a case study using empirical methods applicable to the tropical zones. The related climatological data between January 1983 and December 2014 were collected in Ogun-Oshun River Basin Development Authority (OORBDA, Ogun State, Nigeria. The results showed that groundwater recharge was 194.7 mm per year, evapotranspiration was 1296.2 mm per year, and the recharge coefficient was 20.2% for the study area. The result showed that about 11% of rainfall infiltrated the aquifer, 73% was loss to evapotranspiration, and 36% ended up as run-off. Correlation between climatic parameters and groundwater recharge showed the highest correlation between recharge and rainfall. Temperature, humidity, solar radiation and evapotranspiraton were at the 0.01 significance level, and the results of linear regressions proved that precipitation has a significant effect (with R2 = 0.983 on estimated recharge.
Tillman, Fred D; Gangopadhyay, Subhrendu; Pruitt, Tom
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.
Tillman, Fred; Gangopadhyay, Subhrendu; Pruitt, Tom
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.
B. Leterme; D. Mallants; Jacques, D.
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. Gro...
Graf Renata; Przybyłek Jan
In the paper we present the results of shallow groundwater recharge estimation using the WetSpass GISbased distributed water balance model. By taking into account WetSpass, which stands for Water an Energy Transfer between Soil, Plants and Atmosphere under quasi-Steady State, for average conditions during the period 1961–2000, we assessed the spatial conditions of the groundwater infiltration recharge process of shallow circulation systems in the Poznan Plateau area (the Great Pol...
Hong Wang; Jianen Gao; Xinghua Li; Hongjie Wang; Yuanxing Zhang
Measures of soil and water conservation (SWC) could affect the hydrological process. The impacts of typical measures on groundwater recharge, levels and flow were analyzed based on simulated rainfall experiments and a groundwater model. The three-dimensional finite-difference groundwater flow model (MODFLOW) was calibrated and verified for bare slope, grassland and straw mulching scenarios based on the experiments. The results of the verification in groundwater balance, levels, runoff and fl...
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.
Herrera, Christian; Gamboa, Carolina; Custodio, Emilio; Jordan, Teresa; Godfrey, Linda; Jódar, Jorge; Luque, José A; Vargas, Jimmy; Sáez, Alberto
The Cordillera de la Costa is located along the coastline of northern Chile, in the hyperarid Atacama Desert area. Chemical and isotopic analyses of several small coastal springs and groundwater reservoirs between 22.5 °S and 25.5 °S allow understanding groundwater origin, renewal time and the probable timing of recharge. The aquifers are mostly in old volcanic rocks and alluvial deposits. All spring waters are brackish, of the sodium chloride type due to intensive concentration of precipitation due aridity and for deep groundwater to additional water-rock interaction in slowly renewed groundwater and mixing with deep seated brines. The heavy δ 18 O and δ 2 H values in spring water are explained by recharge by the arrival of moist air masses from the Pacific Ocean and the originally lighter values in the deep wells can be associated to past recharge by air masses coming from the Atlantic Ocean. Current recharge is assumed almost nil but it was significant in past wetter-than-present periods, increasing groundwater reserves, which are not yet exhausted. To explain the observed chloride content and radiocarbon ( 14 C) activity, a well-mixed (exponential) flow model has been considered for aquifer recharge. The average residence time of groundwater feeding the springs has been estimated between 1 and 2kyr, up to 5kyr and between 7 and 13kyr for deep well water, assuming that current recharge is much less than during the previous wetter period. The recharge period feeding the coastal springs could have been produced 1 to 5kyr BP, when the area was already inhabited, and recharge in the Michilla mine was produced during the 10 to 14.5kyr BP CAPE (Central Andean Pluvial Event) pluvial events of the central Andes. The approximate coincidence of turnover time with the past wet periods, as revealed by paleoclimate data, points to significant recharge during them. Copyright © 2017 Elsevier B.V. All rights reserved.
Ganesan, G.; Lakshmanan, E.; Gunalan, J.
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.
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.
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.
Noam Zach Dvory
Full Text Available Sustainable groundwater production from karst aquifers is primarily dictated by its recharge rate. Therefore, it is essential to accurately quantify annual groundwater recharge in order to limit overexploitation and to evaluate artificial methods for groundwater enrichment. Infiltration during erratic flood events in karst basins may substantially contribute to aquifer recharge. However, the complicated nature of karst systems, which are characterized in part by multiple springs, sinkholes, and losing/gaining streams, impede accurate quantification of the actual contribution of flood waters to groundwater recharge. In this study, we aim to quantify the proportion of groundwater recharge accrued during runoff events in a karst aquifer. The role of karst conduits on flash flood infiltration was examined during four flood and controlled runoff events in the Soreq creek near Jerusalem, Israel. We distinguished between direct infiltration, percolation through karst conduits, and diffuse infiltration—the latter of which is most affected by evapotranspiration. A water balance was calculated for the 2014/15 hydrological year using the Hydrologic Engineering Center-Hydrologic Modelling System (HEC-HMS. Simulations show that 6.8 to 19.2% of the annual recharge volume was added to the aquifer from infiltration of runoff losses along the creek through the karst system.
Sethi, Ranu Rani; Kumar, A; Sharma, S P
A study was carried out to select the best method to estimate groundwater recharge in a hard rock terrain. Various standard empirical methods, soil-moisture balance method, water table fluctuation (WTF) method and commonly adopted norms set by Groundwater Estimation Committee (GEC), Govt of India were used to estimate recharge for the Munijhara watershed in the Nayagarh block of Orissa (India). The empirical formulae gave recharge rates ranging from 13 cm to 32 cm/year with average of 22.4 cm and standard deviation of 5.34, independent of other influencing factors like soil, topography and geology. The soil-moisture balance study indicated that recharge is more dependent on the continuous heavy rainfall total annual volume of rainfall. Recharge was limited at up to 10 mm per day, possibly due to presence of hard rock below the soil surface. The rise in water table depth was 3.45 m to 5.35 m with a mean rise of 4.5 m during the year 2006-2007. Annual groundwater recharge based on the WTF approach varied from 10.3 to 16.85 cm with a mean of 13.5 cm, standard deviation of 1.57 cm and coefficient of variation 11.57%. This recharge accounted for 8 to 14% of rainfall received. With a water budget approach based on GEC norms, recharge was calculated as 17 cm per year. The study showed that the magnitudes of annual groundwater recharge as estimated by the WST method and GEC norms are in conformity with other recent findings in India under the same climate conditions. Based on the results recharge structures could be planned in suitable locations to reduce fallow areas under the watershed.
Taylor, R. G.
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.
Eeman, S.; Zee, van der S.E.A.T.M.; Leijnse, A.; Louw, de P.G.B.; Maas, C.
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
Ginige, Maneesha P; Kaksonen, Anna H; Morris, Christina; Shackelton, Mark; Patterson, Bradley M
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.
Tillman, F D; Pool, D R; Leake, S A
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.
Samuel, Manoj P; Senthilvel, S; Mathew, Abraham C
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.
Ground water is a major component of Florida's water resources, accounting for 90 percent of all public-supply and self-supplied domestic water withdrawals, and 58 percent of self-supplied commercial-industrial and agricultural withdrawals of freshwater (Marella, 1992). Ground-water is also an important source of water for streams, lakes, and wetlands in Florida. Because of their importance, a good understanding of these resources is essential for their sound development, use, and protection. One area in which our understanding is lacking is in characterizing the rate at which ground water in aquifers is recharged, and how recharge rates vary geographically. Ground-water recharge (recharge) is the replenishment of ground water by downward infiltration of water from rainfall, streams, and other sources (American Society of Civil Engineers, 1987, p. 222). The recharge rates in many areas of Florida are unknown, of insufficient accuracy, or mapped at scales that are too coarse to be useful. Improved maps of recharge rates will result in improved capabilities for managing Florida's ground-water resources. In 1989, the U.S. Geological Survey, in cooperation with the Florida Department of Environmental Regulation, began a study to delineate high-rate recharge areas in several regions of Florida (Vecchioli and others, 1990). This study resulted in recharge maps that delineated areas of high (greater than 10 inches per year) and low (0 to 10 inches per year) recharge in three counties--Okaloosa, Pasco, and Volusia Counties--at a scale of 1:100,000. This report describes the results of a similar recharge mapping study for Escambia and Santa Rosa Counties (fig. 1), in which areas of high- and low-rates of recharge to the sand-and-gravel aquifer and Upper Floridan aquifer are delineated. The study was conducted in 1992 and 1993 by the U.S. Geological Survey in cooperation with the Florida Department of Environmental Protection.
Hevesi, Joseph A.; Flint, Alan L.; Flint, Lorraine E.
This report presents the development and application of the distributed-parameter watershed model, INFILv3, for estimating the temporal and spatial distribution of net infiltration and potential recharge in the Death Valley region, Nevada and California. The estimates of net infiltration quantify the downward drainage of water across the lower boundary of the root zone and are used to indicate potential recharge under variable climate conditions and drainage basin characteristics. Spatial variability in recharge in the Death Valley region likely is high owing to large differences in precipitation, potential evapotranspiration, bedrock permeability, soil thickness, vegetation characteristics, and contributions to recharge along active stream channels. The quantity and spatial distribution of recharge representing the effects of variable climatic conditions and drainage basin characteristics on recharge are needed to reduce uncertainty in modeling ground-water flow. The U.S. Geological Survey, in cooperation with the Department of Energy, developed a regional saturated-zone ground-water flow model of the Death Valley regional ground-water flow system to help evaluate the current hydrogeologic system and the potential effects of natural or human-induced changes. Although previous estimates of recharge have been made for most areas of the Death Valley region, including the area defined by the boundary of the Death Valley regional ground-water flow system, the uncertainty of these estimates is high, and the spatial and temporal variability of the recharge in these basins has not been quantified. To estimate the magnitude and distribution of potential recharge in response to variable climate and spatially varying drainage basin characteristics, the INFILv3 model uses a daily water-balance model of the root zone with a primarily deterministic representation of the processes controlling net infiltration and potential recharge. The daily water balance includes precipitation
Zhang, Xue; Zhao, Xuan
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.
Booth, E.; Zipper, S. C.; Loheide, S. P.; Kucharik, C. J.
Ecosystem service mapping is a rapidly growing field within ecology and sustainability science. Groundwater recharge is commonly treated as an ecosystem service and it can be estimated using readily available climate and soil parameters. However, groundwater recharge is only the entry-point to a complex groundwater flow system that includes both deep aquifers that municipalities tap into for water supply and shallow aquifers with water tables that can reach the ground surface. From an ecosystem service mapping perspective, groundwater recharge is almost universally treated as a beneficial service by increasing groundwater supply for municipal pumping, baseflow maintenance, and groundwater-dependent ecosystems. However, groundwater recharge can also lead to detrimental impacts such as groundwater flooding that can lead to crop losses (oxygen stress in vegetation) and property damage. While other ecosystem services that are commonly mapped provide benefits in situ (e.g. carbon sequestration), groundwater recharge belongs to a category where effects can be manifested much farther away in both space and time and can be both beneficial and detrimental to several final ecosystem services. This is the case in the Yahara River watershed, an urbanizing agricultural watershed in south-central Wisconsin. We document how groundwater recharge is treated as beneficial towards increasing municipal water supply through increasing use of infiltration practices, which are now legally required by local ordinances. We also show how an increasing precipitation trend has led to the view of groundwater recharge as detrimental towards crop production in fields where groundwater flooding and oxygen stress is evident. However, even in the same field, groundwater recharge can benefit and enhance crop production during drought conditions by decreasing water stress. These complicated and conflicting views of groundwater recharge lead to the recommendation of treating groundwater recharge as
Beigi, E.; Tsai, F. T.
Increases of concentrations of CO2 and other greenhouse gases have a significant effect on global climate, precipitation and hydrology, which in turn influences recharge to aquifers. Groundwater recharge study is imperative to the sole source aquifer, for example the Southern Hills aquifer system in southeastern Louisiana and southwestern Mississippi, which provides more than 50 percent of the drinking water consumed in the area overlying the aquifer and has no substitute drinking water source(s). To trace the climate impact and its consequent groundwater availability, this study developed a GIS-based integrated framework to connect climate models to a high-resolution hydrologic model to quantify long-term groundwater recharge. We employed the Hydrologic Evaluation of Landfill Performance (HELP3) model as our hydrologic model to estimate spatial-temporal distribution of potential recharge for a regional scale. HELP3 model was especially suitable for our recharge study due to Louisiana humid climate and the use of a regional-scale water budget approach. Detailed surficial soil property and land cover were obtained from the NRCS and the USGS to derive maps of curve number for the HELP3 model. Wireline well logs and drillers logs were analyzed to determine stratigraphic lithology and the first major sand encountered beneath the soil layer. For a regional scale, we used global circulation model (GCM) downscaled daily precipitation and temperature obtained from USGS CASCaDE Project Climate Data as the forcing input to the HELP3 model. The emission scenarios considered in this study were A2, B1 and A1FI from Parallel Climate Model 1 (PCM) and from the NOAA Geophysical Fluid Dynamics Lab's GFDL CM2.1 model. We used the computed runoff from USGS WaterWatch along with the HELP3 model to calculate the recharge index (RI) and delineate the recharge index map for individual hydrologic units in terms of Hydrologic Unit Codes (HUCs). The recharge index was defined as the
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 degrees 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
Passarello, M C; Pierce, S A; Sharp, J M
Quantifying groundwater availability depends upon sound methods and the use of integrated models. To determine availability or sustainable yield, the influence of scientific uncertainty from key sources, such as anthropogenic recharge, must be considered. This study evaluates uncertainty in recharge interpretations on the modeled available water balance for an urban case in Texas, USA. Analyses are completed using the Groundwater Decision Support System, which is a research code-base for an integrated modeling. The case study develops spatially and temporally resolved recharge interpretations based on NEXRAD precipitation and detailed land use data. Results demonstrate the implications of scientific uncertainty as it influences recommendations for policy and urban water management decisions that are based on modeled outputs. Geospatial methods account for spatial and temporal components and can be replicated for other systems. These methods are also useful for resolving uncertainty in relation to the influence of urbanization on recharge through land use change.
Starn, J Jeffrey; Bagtzoglou, Amvrossios C; Robbins, Gary A
A Monte Carlo-based approach to assess uncertainty in recharge areas shows that incorporation of atmospheric tracer observations (in this case, tritium concentration) and prior information on model parameters leads to more precise predictions of recharge areas. Variance-covariance matrices, from model calibration and calculation of sensitivities, were used to generate parameter sets that account for parameter correlation and uncertainty. Constraining parameter sets to those that met acceptance criteria, which included a standard error criterion, did not appear to bias model results. Although the addition of atmospheric tracer observations and prior information produced similar changes in the extent of predicted recharge areas, prior information had the effect of increasing probabilities within the recharge area to a greater extent than atmospheric tracer observations. Uncertainty in the recharge area propagates into predictions that directly affect water quality, such as land cover in the recharge area associated with a well and the residence time associated with the well. Assessments of well vulnerability that depend on these factors should include an assessment of model parameter uncertainty. A formal simulation of parameter uncertainty can be used to delineate probabilistic recharge areas, and the results can be expressed in ways that can be useful to water-resource managers. Although no one model is the correct model, the results of multiple models can be evaluated in terms of the decision being made and the probability of a given outcome from each model. Copyright © 2010 The Author(s). Journal compilation © 2010 National Ground Water Association.
Access to surface water is limited in Australia and many regions rely on groundwater for all their water needs. Most of aquifers are already fully allocated and there is an increasing demand for more extraction. During drought, drop in rainfall can result in less recharge into groundwater system. Decrease in rainfall can cause direct and indirect impacts on groundwater. Drop in rainfall can result in less recharge into groundwater system. Moreover decreased rainfall can cause limited accessib...
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
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.
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.
Full Text Available Water resource shortage has been a serious problem since the 1980s in the North China Plain (NCP, resulting in plenty of environmental problems. Estimating the groundwater recharge rate accurately is vital for managing groundwater effectively. This study applied several methods, including chloride mass-balance, tracers (bromide and tritium and numerical modeling (Hydrus-1D, to estimate groundwater recharge at three representative sites of the NCP: Zhengding (ZD, Luancheng (LC and Hengshui (HS. The chloride concentration of the soil profile in the ZD site showed that the mean recharge was 3.84 mm/year with the residence time of 105 years for soil water transferring through the vadose area of 45.0 m in depth in the preferential flow model mainly. Considering the influence of preferential flow on the soil water movement in the field scale, the traditional methods (e.g., peak method of bromide and tritium tracers based on piston flow described in the literature could be unsuitable to estimate groundwater recharge in the LC and HS sites, especially in areas with low recharge rates. Therefore, multi-region and mass balance methods were applied in this study. The results of this investigation showed that the mean values of recharge were 124.3 and 18.0 mm/year in the LC and HS sites, respectively, in 2010. Owing to complexity and uncertainty on the surface resulting from the measuring of evapotranspiration, the upper boundary of 1.4 m (under the ground where most of the plant roots did not reach was chosen for the numerical modeling of Hydrus-1D, and the result showed that the mean recharge was 225 mm/year from 2003 to 2007, consistent with the result of tracers in the previous literature. The result also showed that the positive relation of groundwater recharge and the sum of irrigation and rainfall was presented in the spatial and temporal scale. Additionally, human activities promoted the recharge rate, and recharge rates increased with greater
Cey, Bradley D; Hudson, G Bryant; Moran, Jean E; Scanlon, Bridget R
Dissolved noble gas concentrations in groundwater can provide valuable information on recharge temperatures and enable 3H-3He age-dating with the use of physically based interpretive models. This study presents a large (905 samples) data set of dissolved noble gas concentrations from drinking water supply wells throughout California, representing a range of physiographic, climatic, and water management conditions. Three common interpretive models (unfractionated air, UA; partial re-equilibration, PR; and closed system equilibrium, CE) produce systematically different recharge temperatures or ages; however, the ability of the different models to fit measured data within measurement uncertainty indicates that goodness-of-fit is not a robust indicator for model appropriateness. Therefore caution is necessary when interpreting model results. Samples from multiple locations contained significantly higher Ne and excess air concentrations than reported in the literature, with maximum excess air tending toward 0.05 cm3 STP g(-1) (deltaNe approximately 400%). Artificial recharge is the most plausible cause of the high excess air concentrations. The ability of artificial recharge to dissolve greater amounts of atmospheric gases has important implications for oxidation-reduction dependent chemical reactions. Measured gas concentration ratios suggest that diffusive degassing may have occurred. Understanding the physical processes controlling gas dissolution during groundwater recharge is critical for optimal management of artificial recharge and for predicting changes in water quality that can occur following artificial recharge.
Kowalczyk, Andrzej; Witkowski, Andrzej J.
A Triassic carbonate unit has been intensively drained by zinc and lead ore mines and numerous borehole fields since the nineteenth century. Its groundwater recharge has increased due to: pumping of water from boreholes, mining activity, and urbanization. An approach to determine the amounts of the recharge at a variety of spatial scales is presented in the paper. Different methods were used to identify and quantify recharge components on a regional and local scale: mathematical modelling was performed for four aquifers included in an aquifer system, an analytical estimation based on the assumption that an average recharge is equal to the average discharge of the hydrogeological system—for six man-made drainage centres, and the method of water level fluctuation (WLF) was applied in one observation borehole. Results of modelling have been supplemented by observation of environmental tracers (δ18O, δ2H, 3H), noble gases temperatures, and 4Heexc in groundwater. The regional aquifer’s current recharge according to estimations performed by means of modelling varies from 39 to 101 mm/year on average. Depending on the aquifer site the average precipitation ranges from 779 to 864 mm/year. In the confined part of the aquifer average recharge ranges from 26 to 61 mm/year. Within outcrops average recharge varies from 96 to 370 mm/year. Current recharge estimated by the analytical method for man-made drainage centres varies from 158 up to 440 mm/year. High values are caused by different recharge sources like precipitation, induced leakage from shallow aquifers, and water losses from streams, water mains and sewer systems. Pumping of water, mining and municipal activities constitute additional factors accounting for the intensified recharge.
Pavlovskii, I.; Noorduijn, S. L.; Abrakhimova, P.; Bentley, L. R.; Cey, E. E.; Hayashi, M.
In the water-deficient setting of the Northern Great Plains (or Prairie Pothole Region, PPR), groundwater recharge constitutes only a small fraction of the water budget, meaning that recharge estimates have a high degree of uncertainty. Additionally, recharge primarily occurs as focussed recharge when small topographical depressions are inundated by surface runoff, typically during spring melt while underlying soils are still frozen. This results in a high spatial and temporal variability of recharge rates, which further complicates their evaluation. As part of a major research project called Groundwater Recharge in the Prairies (GRIP), we have developed a soil water balance model to estimate recharge rates at a scale of a single depression and its catchment (recharge mapping on a regional scale in the Edmonton-Calgary corridor in Alberta, located in the north-western fringe of the PPR. The entire area (49500 km2) was divided into elements based on the proximity to one of 24 Alberta Agriculture weather stations. For each element, the model was run for a series of generic scenarios consisting of representative land use and depression catchment parameters. The latter were constructed using a high-resolution digital elevation model (DEM). The recharge value for each element was then computed using a weighted average of the generic scenario outputs. The new method has a number of benefits. Use of generic scenarios instead of real depressions dramatically reduces computational cost. Extraction of relevant parameters from DEM accounts for depressions which are only flooded sporadically and thus may be absent from the inventories of wet areas based on satellite images. If extra data on topographical parameters become available, the recharge may be recalculated without repeating the entire workflow.
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
Eeman, S.; van der Zee, S. E. A. T. M.; Leijnse, A.; de Louw, P. G. B.; Maas, C.
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 characteristics using
Eeman, S.; van der Zee, S. E. A. T. M.; Leijnse, A.; de Louw, P. G. B.; Maas, C.
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 normalized lens volume and the main lens and recharge characteristics, enabling an analytical approximation of the variation of lens thickness. Increase of the recharge amplitude causes increase, and increase of recharge frequency causes 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 center 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 characteristics using basic
He, Jianhua; Ma, Jinzhu; Zhao, Wei; Sun, Shuang
Groundwater recharge and evolution in the Shule River basin, Northwest China, was investigated by a combination of hydrogeochemical tracers, stable isotopes, and radiocarbon methods. Results showed the general chemistry of the groundwater is of SO4 2- type. Water-rock reactions of halite, Glauber's salt, gypsum and celestite, and reverse ionic exchange dictated the groundwater chemistry evolution, increasing concentrations of Cl-, Na+, SO4 2-, Ca2+, Mg2+ and Sr2+ in the groundwater. The δ18O and δ2H values of groundwater ranged from -10.8 to -7.7 and -74.4 to -53.1 ‰, respectively. Modern groundwater was identified in the proluvial fan and the shallow aquifer of the fine soil plain, likely as a result of direct infiltration of rivers and irrigation returns. Deep groundwater was depleted in heavy isotopes with 14C ages ranging from 3,000 to 26,000 years, suggesting palaeowater that was recharged during the late Pleistocene and middle Holocene epochs under a cold climate. These results have important implications for groundwater management in the Shule River basin, since large amounts of groundwater are effectively being mined and a water-use strategy is urgently needed.
Gates, John B.; Steele, Gregory V.; Nasta, Paolo; Szilagyi, Jozsef
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.
Subramani, T; Babu, Savithri; Elango, L
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%.
Cartwright, Ian; Cendón, Dioni; Currell, Matthew; Meredith, Karina
Documenting the location and magnitude of groundwater recharge is critical for understanding groundwater flow systems. Radioactive tracers, notably 14C, 3H, 36Cl, and the noble gases, together with other tracers whose concentrations vary over time, such as the chlorofluorocarbons or sulfur hexafluoride, are commonly used to estimate recharge rates. This review discusses some of the advantages and problems of using these tracers to estimate recharge rates. The suite of tracers allows recharge to be estimated over timescales ranging from a few years to several hundred thousand years, which allows both the long-term and modern behaviour of groundwater systems to be documented. All tracers record mean residence times and mean recharge rates rather than a specific age and date of recharge. The timescale over which recharge rates are averaged increases with the mean residence time. This is an advantage in providing representative recharge rates but presents a problem in comparing recharge rates derived from these tracers with those from other techniques, such as water table fluctuations or lysimeters. In addition to issues relating to the sampling and interpretation of specific tracers, macroscopic dispersion and mixing in groundwater flow systems limit how precisely groundwater residence times and recharge rates may be estimated. Additionally, many recharge studies have utilised existing infrastructure that may not be ideal for this purpose (e.g., wells with long screens that sample groundwater several kilometres from the recharge area). Ideal recharge studies would collect sufficient information to optimise the use of specific tracers and minimise the problems of mixing and dispersion.
Meredith, K. T.; Han, L. F.; Cendón, D. I.; Crawford, J.; Hankin, S.; Peterson, M.; Hollins, S. E.
The Canning Basin is the largest sedimentary basin in Western Australia and is located in one of the most cyclone prone regions of Australia. Despite its importance as a future resource, limited groundwater data is available for the Basin. The main aims of this paper are to provide a detailed understanding of the source of groundwater recharge, the chemical evolution of dissolved inorganic carbon (DIC) and provide groundwater age estimations using radiocarbon (14CDIC). To do this we combine hydrochemical and isotopic techniques to investigate the type of precipitation that recharge the aquifer and identify the carbon processes influencing 14CDIC, δ13CDIC, and [DIC]. This enables us to select an appropriate model for calculating radiocarbon ages in groundwater. The aquifer was found to be recharged by precipitation originating from tropical cyclones imparting lower average δ2H and δ18O values in groundwater (-56.9‰ and -7.87‰, respectively). Water recharges the soil zone rapidly after these events and the groundwater undergoes silicate mineral weathering and clay mineral transformation processes. It was also found that partial carbonate dissolution processes occur within the saturated zone under closed system conditions. Additionally, the processes could be lumped into a pseudo-first-order process and the age could be estimated using the 14C statistical approach. In the single-sample-based 14C models, 14C0 is the initial 14CDIC value used in the decay equation that considers only 14C decay rate. A major advantage of using the statistical approach is that both 14C decay and geochemical processes that cause the decrease in 14CDIC are accounted for in the calculation. The 14CDIC values of groundwater were found to increase from 89 pmc in the south east to around 16 pmc along the groundwater flow path towards the coast indicating ages ranging from modern to 5.3 ka. A test of the sensitivity of this method showed that a ∼15% error could be found for the oldest
Moran, J. E.; Peters, E.; Visser, A.; Esser, B. K.; Singleton, M. J.
A warming climate will bring drastic changes to hydrologic systems in the headwater basins of the major rivers in California. Runoff in these rivers fills the reservoirs that sustain cities and agriculture through the dry months, while cool, late season groundwater discharge to streams is critical for sustaining subalpine ecosystems. Despite the important role they play in the larger hydrologic system, groundwater flow paths in headwater basins are typically not well characterized, with recharge and discharge locations largely unidentified, and subsurface residence times unknown. We examined several groundwater residence time tracers, stable isotopes and noble gas recharge temperatures in samples from wells and springs on Mount Shasta at the headwaters of the Sacramento River. 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. This study was carried out during drought years, when the influence of runoff and recent recharge were minimal. 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 and 2900 m (6600 and 9500 ft), which coincides with areas of thin soils and barren land cover. The large springs in Mt Shasta City discharge at an elevation more than 1500 m lower. High elevation springs (>2000 m) yield very young water (water with a residence time of 6 years or more, based on tritium concentrations in sampled water. Residence time indicators with shorter half-lives (35-Sulfur and 22-Sodium) were not detected, suggesting that very recent recharge was a negligibly small component at the time of sampling. Combined with recharge elevation estimates, ages indicate horizontal flow velocities between 0.5 and 1 km per year. Differences
A. P. VERMA
Full Text Available An analytical expression for the moisture content distribution,
in a problem of one dimensional vertical groundwater recharge, has
been obtained by using the Laplace transform method. The average diffusivity coefficient over the whole range of moisture content is regarded as constant, and a linear variation of permeability with moisture content is assumed.
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
Magruder, Ian A; Woessner, William W; Running, Steve W
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.
Schmidt, C. M.; Russo, T. A.; Fisher, A. T.; Racz, A. J.; Wheat, C. G.; Los Huertos, M.; Lockwood, B. S.
Groundwater is likely to become increasingly important for irrigated agriculture due to anticipated changes to the hydrologic cycle associated with climate change. Protecting the quantity and quality of subsurface water supplies will require flexible management strategies that can enhance groundwater recharge. We present results from a study of managed aquifer recharge (MAR) in central coastal California, and propose the use of distributed, small-scale (1-5 ha) MAR systems to improve the quantity and quality of recharge in agricultural basins. Our field site is located in a basin where the primary use of groundwater is irrigation for agriculture, and groundwater resources are increasingly threatened by seawater intrusion and nutrient contamination from fertilizer application. The MAR system we are monitoring is supplied by stormwater and irrigation runoff of variable quality, which is diverted from a wetland during periods of high flow. This MAR system delivers approximately 1x106 m3 of recharge annually to the underlying aquifer, a portion of which is recovered and distributed to growers during the dry season. Our sampling and measurements (at high spatial and temporal resolution) show that a significant percentage of the nitrogen load added during MAR operation is eliminated from recharge during shallow infiltration (~30% to 60%, ~40 kg NO3-N/d). Isotopic analyses of the residual nitrate indicate that a significant fraction of the nitrate load reduction is attributable to denitrification. When normalized to infiltration pond area, this system achieves a mean load reduction of 7 kg NO3-N/d/ha, which compares favorably with the nitrogen load reduction efficiency achieved by treatment wetlands receiving agricultural runoff. Much of the reduction in nitrogen load occurs during periods of rapid infiltration (0.2 to 2.0 m/day), as demonstrated with point measurements of infiltration rate collocated with fluid samples. These results suggest that developing a network of
Keesari, Tirumalesh; Sharma, Diana A; Rishi, Madhuri S; Pant, Diksha; Mohokar, Hemant V; Jaryal, Ajay Kumar; Sinha, U K
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.
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.
Zhang, Yang-Qing; Wang, Jian-Hua; Chen, Jin-Jian; Li, Ming-Guang
Groundwater drawdown and strata settlements induced by dewatering in confined aquifers can be relieved by artificial recharge. In this study, numerical simulations of a field multi-well pumping-recharge test in a deep confined aquifer are conducted to analyze the responses of groundwater and strata to pumping and recharge. A three-dimensional numerical model is developed in a finite-difference software, which considers the fluid-mechanical interaction using the Biot consolidation theory. The predicted groundwater drawdown and ground settlements are compared to the measured data to confirm the validation of the numerical analysis of the pumping and recharge. Both numerical results and measured data indicate that the effect of recharge on controlling the groundwater drawdown and strata settlements correlates with the injection rate and well arrangements. Since the groundwater drawdown induced by pumping can be controlled by artificial recharge, soil compression can be relieved by reducing the changes of effective stress of the soils. Consequently, strata settlement induced by pumping can be relieved by artificial recharge and ground settlements can be eliminated if an appropriate injection rate and well arrangement are being determined. Moreover, the changes of the pore pressure and seepage force induced by pumping and recharge will also result in significant horizontal deformations in the strata near the recharge wells.
Masbruch, Melissa D.; Rumsey, Christine; Gangopadhyay, Subhrendu; Susong, David D.; Pruitt, Tom
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.
Jayawickreme, Dushmantha Helapriya
Global energy, water, and bio-geochemical cycles are strongly linked to land-use and land-cover characteristics. Land-use and land-cover is also a component of the environment extensively impacted and continuously altered by human activity. Population growth, food, energy and other needs coupled with human ingenuity has greatly altered and will continue to change the terrestrial biosphere across the globe. With additional concerns for significant and widespread land-use/land-cover transformations due to global climate change, a need to better understand the effects of these transformations on environmental systems from local, regional, to global scale has emerged in the recent decades. In this dissertation I have investigated the impacts of land-use and land-cover (i.e. vegetation) on groundwater recharge, which is a critical component of the hydrologic cycle. The dependence of people and many sensitive ecosystems around the world on groundwater alone warranted a closer look at how changing land-use/cover and climate are affecting the quantity and quality of groundwater. By evaluating streamflow, climate, land-cover, and other attributes in Michigan's watersheds we showed that intense agriculture reduced summer time streamflow, hence groundwater recharge in such watersheds. By quantifying baseflow discharges relative to precipitation in July-September peak growing season over multiple years we found that recharge in primarily agricultural (>70 agricultural uses by land area) watersheds was only one third of the recharge in watersheds that are mix use (land-cover; specifically vegetation, vegetation differences, and vegetation dynamics affect recharge we adopted geophysical techniques, a step beyond the traditional uses of geophysical methods as well as an unorthodox approach to terrestrial ecosystem investigations. It was hypothesized that there would be observable differences in the way vegetation interacts with the shallow subsurface and such interactions could
Kim, T.; Lee, K.
Groundwater is widely used as natural resources for the drink, spa, etc., and a supplement to the official and/or natural water supply. In these cases, the establishment of water balance model can provide a safe and effective usage of resources. To establish the appropriate water balance model and the design of water usage, recharge rate must be estimated with an allowed accuracy. For these purposes, many methods were suggested to estimate recharge rate. One of most popular methods in recent years is measuring groundwater age with environmental tracer(Solomon et. al., 1993; Leduc et. al., 1997; Bromley et. al., 1997; Williams, 1997; Ayalon et. al. 1998). Using the distributed environmental tracer, the vertical profile of groundwater age can be composed, and recharge rate can be estimated with the composed profile. Water budget analysis can be the other one of available method(Bradbury and Rushton, 1998; Finch, 1998; Bekesi and McConchie, 1999). However, to explain the expansion of contaminant with temporal variation of unsaturated flow, sequential estimation of recharge must be needed. Unfortunately, it is a very hard work to find out some studies on sequential approaches to estimate the recharge rate to groundwater. Even predictive deconvolution technique was rarely. In general, minimum phase condition, preposition of classical predictive deconvolution, can hardly be satisfied in nature. On the contrary, the input signal in natural system can be considered as a random signal. To avoid the strong restriction of minimum phase condition, Wiggins(1978) proposed minimum entropy deconvolution(MED) with varimax norm. However, solution process with varimax norm is non-linear. For the linearization of MED problem, Carbrelli suggested another criterion, D norm(1984). In this study, MED with D norm was applied to the estimation of the sequence of relative recharge rate, and the applicability of MED to evaluation of recharge sequence was investigated. To check out the
Neumann, R. B.; Ashfaque, K. N.; Badruzzaman, A. M.; Ali, M.; Shoemaker, J. K.; Harvey, C. F.
Researchers have puzzled over the origin of dissolved arsenic in the aquifers of the Ganges Delta since widespread arsenic poisoning from groundwater was publicized two decades ago. Previous work has concluded that biological oxidation of organic carbon drives geochemical transformations that mobilize arsenic from sediments; however, the source of the organic carbon that fuels these processes remains controversial. A combined hydrologic and biogeochemical analysis of a typical site in Bangladesh, where constructed ponds and groundwater-irrigated rice fields are the main sources of recharge, shows that only recharge through pond sediments provides the biologically degradable organic carbon that can drive arsenic mobilization. Numerical groundwater simulations as well as chemical and isotopic indicators suggest that contaminated groundwater originates from excavated ponds and that water originating from rice fields is low in arsenic. In fact, rice fields act as an arsenic sink. Irrigation moves arsenic-rich groundwater from the aquifers and deposits it on the rice fields. Most of the deposited arsenic does not return to the aquifers; it is sorbed by the field’s surface soil and bunds, and is swept away in the monsoon floods. The findings indicate that patterns of arsenic contamination in the shallow aquifer are due to recharge-source variation and complex three-dimensional flow.
Xie, Y.; Cook, P. G.; Simmons, C. T.; Partington, D.; Crosbie, R.; Batelaan, O.
Coupled soil-vegetation-atmosphere models have become increasingly popular for estimating groundwater recharge, because of the integration of carbon, energy and water balances. The carbon and energy balances act to constrain the water balance and as a result should reduce the uncertainty of groundwater recharge estimates. However, the addition of carbon and energy balances also introduces a large number of plant physiological parameters which complicates the estimation of groundwater recharge. Moreover, this method often relies on existing pedotransfer functions to derive soil water retention curve parameters and saturated hydraulic conductivity from soil attribute data. The choice of a pedotransfer function is usually subjective and several pedotransfer functions may be fit for the purpose. These different pedotransfer functions (and thus the uncertainty of soil water retention curve parameters and saturated hydraulic conductivity) are likely to increase the prediction uncertainty of recharge estimates. In this study, we aim to assess the potential uncertainty of groundwater recharge when using a coupled soil-vegetation-atmosphere modelling method. The widely used WAter Vegetation Energy and Solute (WAVES) modelling code was used to perform simulations of different water balances in order to estimate groundwater recharge in the Campaspe catchment in southeast Australia. We carefully determined the ranges of the vegetation parameters based upon a literature review. We also assessed a number of existing pedotransfer functions and selected the four most appropriate. Then the Monte Carlo analysis approach was employed to examine potential uncertainties introduced by different types of errors. Preliminary results suggest that for a mean rainfall of about 500 mm/y and annual pasture vegetation, the estimated recharge may range from 10 to 150 mm/y due to the uncertainty in vegetation parameters. This upper bound of the recharge range may double to 300 mm/y if different
Naff, R.L.; Gutjahr, A.L.
A model is proposed that relates water level fluctuations in a Dupuit aquifer to effective precipitation at the top of the unsaturated zone. Effective precipitation, defined herein as that portion of precipitation which becomes recharge, is related to precipitation measured in a nearby gage by a two-parameter function. A second-order stationary assumption is used to connect the spectra of effective precipitation and water level fluctuations.-from Authors
Akbariyeh, S.; Wang, T.; Bartelt-Hunt, S.; Li, Y.
Climate variability and change will impose profound influences on groundwater systems. Accurate estimation of groundwater recharge is extremely important for predicting the flow and contaminant transport in the subsurface, which, however, remains as one of the most challenging tasks in the field of hydrology. Using an inverse modeling technique and HYDRUS 1D software, we predicted the spatial distribution of groundwater recharge across the Upper Platte basin in Nebraska, USA, based on 5-year projected future climate and soil moisture data (2057-2060). The climate data was obtained from Weather Research and Forecasting (WRF) model under RCP 8.5 scenario, which was downscaled from global CCSM4 model to a resolution of 24 by 24 km2. Precipitation, potential evapotranspiration, and soil moisture data were extracted from 76 grids located within the Upper Platte basin to perform the inverse modeling. Hargreaves equation was used to calculate the potential evapotranspiration according to latitude, maximum and minimum temperature, and leaf area index (LAI) data at each node. Van-Genuchten parameters were optimized using the inverse algorithm to minimize the error between input and modeled soil moisture data. The groundwater recharge was calculated as the amount of water that passed the lower boundary of the best fitted model. The year of 2057 was used as a spin-up period to minimize the impact of initial conditions. The model was calibrated for years 2058 to 2059 and validation was performed for 2060. This work demonstrates an efficient approach to estimating groundwater recharge based on climate modeling results, which will aid groundwater resources management under future climate scenarios.
Beigi, Ehsan; Tsai, Frank T.-C.
A geographic information system (GIS)-based water-budget framework has been developed to study the climate-change impact on regional groundwater recharge, and it was applied to the Southern Hills aquifer system of southwestern Mississippi and southeastern Louisiana, USA. The framework links historical climate variables and future emission scenarios of climate models to a hydrologic model, HELP3, to quantify spatiotemporal potential recharge variations from 1950 to 2099. The framework includes parallel programming to divide a large amount of HELP3 simulations among multiple cores of a supercomputer, to expedite computation. The results show that a wide range of projected potential recharge for the Southern Hills aquifer system resulted from the divergent projections of precipitation, temperature and solar radiation using three scenarios (B1, A2 and A1FI) of the National Center for Atmospheric Research's Parallel Climate Model 1 (PCM) and the National Oceanic and Atmospheric Administration Geophysical Fluid Dynamics Lab's (GFDL) model. The PCM model projects recharge change ranging from -33.7 to +19.1 % for the 21st century. The GFDL model projects less recharge than the PCM, with recharge change ranging from -58.1 to +7.1 %. Potential recharge is likely to increase in 2010-2039, but likely to decrease in 2070-2099. Projected recharge is more sensitive to the changes in the projected precipitation than the projected solar radiation and temperature. Uncertainty analysis confirms that the uncertainty in projected precipitation yields more changes in the potential recharge than in the projected temperature for the study area.
Nolan, B. T.; Baehr, A. L.
The spatial variability of ground-water recharge estimates in the Glassboro area, NJ, was evaluated using geostatistical methods as a preliminarily assessment of aquifer vulnerability. Recharge was estimated using Darcy's law, based on parameters obtained from pedotransfer functions applied to measured soil texture values. The recharge estimates correspond to sediments overlying the Kirkwood-Cohansey aquifer, which comprises highly permeable unconsolidated sands and gravels. Knowing which areas receive greater recharge would indicate areas of greater vulnerability, depending on overlying land use. Recharge varied from -7.3 to 722 in/yr in the study area and the median was 12.1 in/yr. Experimental variograms of untransformed recharge data were erratic and related kriged maps were dominated by extreme values (250-722 in/yr) in the data set. An indicator transform stabilized the variograms. Indicator kriging (IK) reduced the influence of extreme values in the data set and yielded maps showing the probability of exceeding threshold values of recharge in the study area. The probability of exceeding the median recharge rate of 12.1 in/yr was 0.9 in the southern portion of the study area and might represent an area of focused recharge. As a check of model fit, probabilities predicted with IK were compared with the original recharge estimates and found to be strongly related. IK predictions corresponding to quintiles of recharge were used to estimate cumulative distribution functions (cdfs) for specific locations in the study area. The cdfs indicate the probability of exceeding any recharge rate at a particular location, and are shaped differently depending on location in the study area. The IK technique estimates cdfs with a single sampling realization (i.e., without a mean and variance at a given location). Additional variables were analyzed with regression to add a deterministic aspect to the analysis and to improve predictions. These variables included land slope
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.
Spannenberg, Jescica; Atangana, Abdon; Vermeulen, P. D.
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.
Kupfersberger, Hans; Stadler, Hermann
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
Vijay, Ritesh; Sohony, R A
The groundwater in India is facing a critical situation due to over exploitation, reduction in recharge potential by change in land use and land cover and improper planning and management. A groundwater development plan needs a large volume of multidisciplinary data from various sources. A geographic information system (GIS) based hydrogeomorphic approach can provide the appropriate platform for spatial analysis of diverse data sets for decision making in groundwater recharge. The paper presents development of GIS based model to provide more accuracy in identification and suitability analysis for finding out zones and locating suitable sites with suggested structures for artificial recharge. Satellite images were used to prepare the geomorphological and land use maps. For site selection, the items such as slope, surface infiltration, and order of drainage were generated and integrated in GIS using Weighted Index Overlay Analysis and Boolean logics. Similarly for identification of suitable structures, complex matrix was programmed based on local climatic, topographic, hydrogeologic and landuse conditions as per artificial recharge manual of Central Ground Water Board, India. The GIS based algorithm is implemented in a user-friendly way using arc macro language on Arc/Info platform.
Robertson, C. A.; Paukert Vankeuren, A. N.; Wagner, A. J.; Blackburn, C.; Druecker, D.
Characterizing recharge will be critical for sustainable groundwater use, particularly following California's historic five-year drought . Groundwater is of great importance to Sacramento, which is a high priority basin as determined by the Sustainable Groundwater Management Act of 2014. The California State University, Sacramento (CSUS) campus has 18 monitoring wells, making it an ideal laboratory for examination of recharge sources and water quality in confined and unconfined aquifers in the Central Valley aquifer system. Historically, CSUS aquifers appear to have been recharged by water from the Western Sierra Nevada. The campus is bounded by the Lower American River, and some of its wells are in hydraulic connection with the river1. Lower than average river stage during the drought may have affected recharge to the aquifers from the river. Additionally, low impact development (LID) stormwater-management ponds have recently been installed on campus in an effort to increase infiltration and to help mitigate contamination of the aquifers and American River from campus runoff. The recently installed LID ponds on campus may have increased infiltration of local precipitation into the unconfined aquifer. Data collected from the monitoring wells allow for the examination of differences between the confined and unconfined aquifer systems in the Central Valley. To identify recharge sources, stable isotope and major ion analyses for samples collected from both campus aquifers are compared to samples from local precipitation and rivers in the Western Sierra Nevada feeding the American River. These results are used to assess current water quality and compared to historic datasets collected by the USGS to reveal changes that have occurred as a result of the recent drought. These data are the first in a dataset developed by CSUS Geology students for long-term monitoring of local groundwater quality. 1Moran et al., 2004. LLNL, UCR-203258.
Ma, Yeping; Li, Miao; Wu, Miaomiao; Li, Zhen; Liu, Xiang
To develop a better understanding of the pollution conditions of antibiotics during the groundwater recharge process, a nation-wide survey was conducted across China for the first time. Overall, 15 recharge sites employing reclaimed water located in different humid, semi-humid and semi-arid regions were selected for analysis of the presence of the 20 most commonly used antibiotics, including tetracyclines (TCs), fluoroquinolones (FQNs), sulfonamides (SAs) and macrolides. All types of antibiotics were detected at concentrations of 212-4035 ng/L in reclaimed water and 19-1270 ng/L in groundwater. FQNs were the predominant antibiotics in reclaimed water samples (38%), followed by SAs (34%). In the SAs group, sulfamethoxazole (SMZ) and sulfamonomethoxine together with trimethoprim accounted for 78% of the total, while ofloxacin (OFL) and norfloxacin accounted for 90% of the FQNs, and doxycycline and oxytetracycline accounted for 82% of the TCs. The concentrations in groundwater were generally 1-2 orders of magnitude lower than in reclaimed water. The three most common antibiotics were OFL, erythromycin (ERY) and SMZ. Similar occurrences of different group antibiotics might be evidence of the influence of groundwater recharge by reclaimed water. FQNs were predominant in northern China, while SAs were predominant in the south. Ecotoxicological risk assessment showed that SMZ, ERY and OFL had the top three hazard quotient values, indicating they should receive preferential treatment before recharging. Overall, these results provide a theoretical basis for development of a recharge standard in China. Copyright © 2015 Elsevier B.V. All rights reserved.
Werner, Micha; Westerhoff, Rogier; Moore, Catherine
Quantitative estimates of recharge due to precipitation excess are an important input to determining sustainable abstraction of groundwater resources, as well providing one of the boundary conditions required for numerical groundwater modelling. Simple water balance models are widely applied for calculating recharge. In these models, precipitation is partitioned between different processes and stores; including surface runoff and infiltration, storage in the unsaturated zone, evaporation, capillary processes, and recharge to groundwater. Clearly the estimation of recharge amounts will depend on the estimation of precipitation volumes, which may vary, depending on the source of precipitation data used. However, the partitioning between the different processes is in many cases governed by (variable) intensity thresholds. This means that the estimates of recharge will not only be sensitive to input parameters such as soil type, texture, land use, potential evaporation; but mainly to the precipitation volume and intensity distribution. In this paper we explore the sensitivity of recharge estimates due to difference in precipitation volumes and intensity distribution in the rainfall forcing over the Canterbury region in New Zealand. We compare recharge rates and volumes using a simple water balance model that is forced using rainfall and evaporation data from; the NIWA Virtual Climate Station Network (VCSN) data (which is considered as the reference dataset); the ERA-Interim/WATCH dataset at 0.25 degrees and 0.5 degrees resolution; the TRMM-3B42 dataset; the CHIRPS dataset; and the recently releases MSWEP dataset. Recharge rates are calculated at a daily time step over the 14 year period from the 2000 to 2013 for the full Canterbury region, as well as at eight selected points distributed over the region. Lysimeter data with observed estimates of recharge are available at four of these points, as well as recharge estimates from the NGRM model, an independent model
Solomon, D. K.; Schiff, S. L.; Poreda, R. J.; Clarke, W. B.
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.
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
Dawes, W.; Ali, R.; Varma, S.; Emelyanova, I.; Hodgson, G.; McFarlane, D.
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 clayey surface soils restricts possible
Wallner, Markus; Houben, Georg; Lohe, Christoph; Quinger, Martin; Himmelsbach, Thomas
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.
Wallner, Markus; Houben, Georg; Lohe, Christoph; Quinger, Martin; Himmelsbach, Thomas
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.
Cooper, Clay A [DRI; Hershey, Ronald L [DRI; Healey, John M [DRI; Lyles, Brad F [DRI
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.
Krest, J.M.; Harvey, J.W.
Radium activity in pore water of wetland sediments often differs from the amount expected from local production, decay, and exchange with solid phases. This disequilibrium results from vertical transport of radium with groundwater that flows between the underlying aquifer and surface water. In situations where groundwater recharge or discharge is significant, the rate of vertical water flow through wetland sediment can be determined from the radium disequilibrium by a combined model of transport, production, decay, and exchange with solid phases. We have developed and tested this technique at three sites in the freshwater portion of the Everglades by quantifying vertical advective velocities in areas with persistent groundwater recharge or discharge and estimating a coefficient of dispersion at a site that is subject to reversals between recharge and discharge. Groundwater velocities (v) were determined to be between 0 and -0.5 cm d-1 for a recharge site and 1.5 ?? 0.4 cm d-1 for a discharge site near Levee 39 in the Everglades. Strong gradients in 223Ra and 224Ra usually occurred at the base of the peat layer, which avoided the problems of other tracers (e.g., chloride) for which greatest sensitivity occurs near the peat surface - a zone readily disturbed by processes unrelated to groundwater flow. This technique should be easily applicable to any wetland system with different production rates of these isotopes in distinct sedimentary layers or surface water. The approach is most straightforward in systems where constant pore-water ionic strength can be assumed, simplifying the modeling of radium exchange.
After four years of drought, groundwater levels in the Salinas Valley are at historically low levels which threaten to adversely affect farming in the Salinas Valley. Given the prospect of a strong El Niño this coming winter, it seems prudent to plan to capture as much of the rainfall as possible to...
Apr 13, 2012 ... Land use change is a major factor influencing catchment hydrology and groundwater resources. In South Africa, the man- agement of scarce water resources is a big concern. The study area, the upper Berg catchment, Western Cape, South Africa, contains strategic water resources. The catchment has ...
Huang, Tianming; Pang, Zhonghe; Liu, Jilai; Ma, Jinzhu; Gates, John
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.
Huang, Tianming; Pang, Zhonghe; Liu, Jilai; Ma, Jinzhu; Gates, John
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.
McMahon, P.B.; Plummer, L.N.; Böhlke, J.K.; Shapiro, S.D.; Hinkle, S.R.
An overview is presented of existing groundwater-age data and their implications for assessing rates and timescales of recharge in selected unconfined aquifer systems of the United States. Apparent age distributions in aquifers determined from chlorofluorocarbon, sulfur hexafluoride, tritium/helium-3, and radiocarbon measurements from 565 wells in 45 networks were used to calculate groundwater recharge rates. Timescales of recharge were defined by 1,873 distributed tritium measurements and 102 radiocarbon measurements from 27 well networks. Recharge rates ranged from useful insights into spatial and temporal variability in recharge at a national scale and factors controlling that variability. Local age-based recharge estimates provide empirical data and process information that are needed for testing and improving more spatially complete model-based methods.
Grygoruk, Mateusz; Kotowski, Wiktor
Groundwater recharge plays the crucial role in development and stability of fens. It was hypothesized that the mid- and late-Holocene acceleration of fens' development in Europe could have been induced by changes in land cover: decreasing areas of forests resulting from the expanding agriculture have enhanced groundwater recharge by decreasing evapotranspiration and interception and promoting infiltration. However, regardless human-related changes of the landscape, recorded climatic fluctuations could also be considered as drivers of changing groundwater recharge that affects fen stability and development. Nowadays, when up to 90% of European wetlands is considered degraded, assessing vulnerability of groundwater recharge to changing landscape and climate is of the crucial importance for setting fen restoration and management strategies. Main goal of our study was to assess the magnitude of changes in groundwater recharge estimation resulting from modelled changes of the landscape and climatic features in >300 fens located in Poland, Germany, The Netherlands, Sweden, UK and Norway. In our approach we (1) delineated the most probable extents of catchments of particular fens analysed, (2) assumed hypothetical and the most probable changes of land cover within these catchments, (3) assumed the most probable ranges of climatic changes in each of the catchments including historical reconstructions (Holocene) and future projections (A1B scenario, CSIRO:MK3 and UKMO:HADCM3 GCM-RCM ensembles), (4) developed, tested and calibrated automatic, GIS-based groundwater recharge calculation algorithm to be applied in the study, (5) calculated groundwater recharge in multiple probable combinations of landscape and climatic conditions and (6) performed statistical analysis in order to reveal whether the climate or landscape changes were the dominant factors that could have probably influenced groundwater recharge in catchments of fens analysed. We revealed that in the case of 80% of
Allocca, V.; De Vita, P.; Manna, F.; Nimmo, John R.
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.
Ali Rahmani, S E; Chibane, Brahim; Boucefiène, Abdelkader
.... In this research we are going to quantify the rate of groundwater recharge using new hybrid model tack in interest the annual rainfall and the average annual temperature and the geological characteristics of the area...
Narula, Kapil K; Gosain, A K
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
Tjahyo Nugroho Adji
that results in groundwater recharge characteristic. The volcanic slope unit (above 600 m as! has the lowest water table fluctuation indicates the resistant comportment to the annual rainfall. Ihis unit is characterized by the relatively high magnitude of recharge of approximately 4270 mm/year.
Dawes, W; Ali, R; Varma, S; Emelyanova, I; Hodgson, G; McFarlane, D
.... 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...
Neumann, Rebecca B; St Vincent, Allison P; Roberts, Linda C; Badruzzaman, A Borhan M; Ali, M Ashraf; Harvey, Charles F
Irrigation of rice fields in Bangladesh with arsenic-contaminated groundwater transfers tens of cubic kilometers of water and thousands of tons of arsenic from aquifers to rice fields each year. Here we combine observations of infiltration patterns with measurements of porewater chemical composition from our field site in Munshiganj Bangladesh to characterize the mobility of arsenic in soils beneath rice fields. We find that very little arsenic delivered by irrigation returns to the aquifer, and that recharging water mobilizes little, if any, arsenic from rice field subsoils. Arsenic from irrigation water is deposited on surface soils and sequestered along flow paths that pass through bunds, the raised soil boundaries around fields. Additionally, timing of flow into bunds limits the transport of biologically available organic carbon from rice fields into the subsurface where it could stimulate reduction processes that mobilize arsenic from soils and sediments. Together, these results explain why groundwater irrigated rice fields act as net sinks of arsenic from groundwater.
Full Text Available In the paper we present the results of shallow groundwater recharge estimation using the WetSpass GISbased distributed water balance model. By taking into account WetSpass, which stands for Water an Energy Transfer between Soil, Plants and Atmosphere under quasi-Steady State, for average conditions during the period 1961-2000, we assessed the spatial conditions of the groundwater infiltration recharge process of shallow circulation systems in the Poznan Plateau area (the Great Poland Lowland in western Poland, which is classified as a region with observed water deficits. For three temporal variants, i.e. year, winter and summer half-years, we determined using the geological infiltration method by about 5-10% on average, marginally by 20%.
Ng, Gene-Hua Crystal; McLaughlin, Dennis; Entekhabi, Dara; Scanlon, Bridget R
..., climate change is likely to affect groundwater resources through changes in precipitation. Precipitation predictions provided by general circulation models (GCMs) vary significantly. Although these models generally agree that global average precipitation will increase with a warmer climate, there is much less agreement about regional changes [IP...
Afrifa, George Yamoah; Sakyi, Patrick Asamoah; Chegbeleh, Larry Pax
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.
Gurdak, Jason J.; Qi, Sharon L.
Recently recharged water (defined here as interactions of natural and anthropogenic controlling factors that influence nitrate occurrence in recently recharged groundwater is critical to support best management and policy decisions that are often made at the aquifer to subaquifer scale. New logistic regression models were developed using data from the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) program and National Water Information System for 17 principal aquifers of the U.S. to identify important source, transport, and attenuation factors that control nonpoint source nitrate concentrations greater than relative background levels in recently recharged groundwater and were used to predict the probability of detecting elevated nitrate in areas beyond the sampling network. Results indicate that dissolved oxygen, crops and irrigated cropland, fertilizer application, seasonally high water table, and soil properties that affect infiltration and denitrification are among the most important factors in predicting elevated nitrate concentrations. Important differences in controlling factors and spatial predictions were identified in the principal aquifer and national-scale models and support the conclusion that similar spatial scales are needed between informed groundwater management and model development.
Full Text Available The impact of climate change and Baltic Sea level rise on groundwater resources in a shallow, unconfined, low-lying coastal aquifer in Hanko, southern Finland, was assessed using the UZF1 model package coupled with the three-dimensional groundwater flow model MODFLOW to simulate flow from the unsaturated zone through the aquifer. The snow and PET models were used to calculate the surface water availability for infiltration from the precipitation data used in UZF1. Infiltration rate, flow in the unsaturated zone and groundwater recharge were then simulated using UZF1. The simulation data from climate and sea level rise scenarios were compared with present data. The results indicated changes in recharge pattern during 2071–2100, with recharge occurring earlier in winter and early spring. The seasonal impacts of climate change on groundwater recharge were more significant, with surface overflow resulting in flooding during winter and early spring and drought during summer. Rising sea level would cause some parts of the aquifer to be under sea level, compromising groundwater quality due to intrusion of sea water. This, together with increased groundwater recharge, would raise groundwater levels and consequently contribute more surface leakage and potential flooding in the low-lying aquifer.
Yan, Zhang; Fadong, Li; Jing, Li; Qiang, Liu; Guangshuai, Zhao
Quantitative estimation of groundwater recharge is crucial for limited water resources management. A combination of isotopic and chemical indicators has been used to evaluate the relationship between surface water, groundwater, and rainfall around the riparian of the Yellow River in the North China Plain (NCP). The ion molar ratio of sodium to chloride in surface- and groundwater is 0.6 and 0.9, respectively, indicating cation exchange of Ca(2+) and/or Mg(2+) for Na(+) in groundwater. The δD and δ(18)O values in rainfall varied from -64.4 to -33.4‰ and from -8.39 to -4.49‰. The groundwater samples have δD values in the range of -68.7 to -58.0‰ and δ(18)O from -9.29 to -6.85‰. The δ(18)O and δD in surface water varied from -8.51 to -7.23‰ and from -64.42 to -53.73‰. The average values of both δD and δ(18)O from surface water are 3.92‰ and 0.57‰, respectively, higher compared to groundwater. Isotopic composition indicated that the groundwater in the riparian area of the Yellow River was influenced by heavy rainfall events and seepage of surface water. The mass balance was applied for the first time to estimate the amount of recharge, which is probably 6% and 94% of the rainfall and surface water, respectively.
Djuma, Hakan; Bruggeman, Adriana; Camera, Corrado; Eliades, Marinos
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
Full Text Available (CMB) approach, and a value of 5% using a GIS-based groundwater recharge algorithm, and a value of 13% in the vicinity of Riverlands (DWAF, 2006). Another study in the area reported recharge values of 26% of rainfall (380 mm/a) using a water balance... method at Atlantis (20 km south of Riverlands) (Vandoolaeghe and Bertram, 1982). Bredenkamp (1982) modelled the conditions at Atlantis and came up with a recharge rate of 21% of total rainfall (350 mm/a). The recharge rate was reconsidered as 0...
Mensah, Felix Oteng; Alo, Clement; Yidana, Sandow Mark
This study tests the representativeness of groundwater recharge estimates through the chloride mass balance (CMB) method in a tropical environment. The representativeness of recharge estimates using this methodology is tested using evaporation estimates from isotope data, the general spatial distribution of the potential field, and the topographical variations in the area. This study suggests that annual groundwater recharge rates in the area ranges between 0.9% and 21% of annual precipitation. These estimates are consistent with evaporation rates computed from stable isotope data of groundwater and surface water in the Voltaian Basin. Moreover, estimates of groundwater recharge through numerical model calibration in other parts of the terrain appear to be consistent with the current data in this study. A spatial distribution of groundwater recharge in the area based on the estimated data takes a pattern akin to the spatial pattern of distribution of the hydraulic head, the local topography, and geology of the terrain. This suggests that the estimates at least qualitatively predicts the local recharge and discharge locations in the terrain.
Smith, Erik A.; Westenbroek, Stephen M.
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).
Oteng Mensah, Felix; Alo, Clement
This study tests the representativeness of groundwater recharge estimates through the chloride mass balance (CMB) method in a tropical environment. The representativeness of recharge estimates using this methodology is tested using evaporation estimates from isotope data, the general spatial distribution of the potential field, and the topographical variations in the area. This study suggests that annual groundwater recharge rates in the area ranges between 0.9% and 21% of annual precipitation. These estimates are consistent with evaporation rates computed from stable isotope data of groundwater and surface water in the Voltaian Basin. Moreover, estimates of groundwater recharge through numerical model calibration in other parts of the terrain appear to be consistent with the current data in this study. A spatial distribution of groundwater recharge in the area based on the estimated data takes a pattern akin to the spatial pattern of distribution of the hydraulic head, the local topography, and geology of the terrain. This suggests that the estimates at least qualitatively predicts the local recharge and discharge locations in the terrain. PMID:24772021
Rigby, J.; Haugh, C. J.; Barlow, J.
The Lower Mississippi River Basin is one of the major agricultural production regions in the United States producing over two-thirds of the rice, nearly half of sugarcane produced in the U.S., as well as significant amounts of soybeans, corn, and cotton. While the region experiences over 50 inches of precipitation annually, reaching yield potential for crops requires irrigation. Approximately 75% of crop acres in the alluvial valley are irrigated, and the expectation is that all acreage will eventually be irrigated. Currently over 90% of water for crop irrigation is derived from the shallow alluvial aquifer outpacing net recharge by several million acre-feet per year. This has resulted in severe groundwater declines in Arkansas and an increasingly threatening situation in northwestern Mississippi. In Mississippi, direct injection has received increasing attention as a means of artificial recharge, though water quality remains a concern both for the integrity of the aquifer and efficiency of injection. This project considers the use of pumping wells near major rivers known to be in connection with the aquifer to induce additional infiltration of surface water by steepening local gradients. The pumped water would be transferred by pipeline to areas within the regional cone of depression where it is then injected to enhance groundwater recharge. Groundwater flow modeling with zone budget analysis is used to evaluate the potential for net supply gains from induced infiltration at potential sites along major rivers in the region. The groundwater model will further evaluate the impact of the transfer and direct injection on regional water tables.
Inoue, Keisuke; Nakazato, Hiroomi; Kubota, Tomijiro; Takeuchi, Mutsuo; Sugimoto, Yoshihiro; Kim, Hee Joon; Furue, Koji
An artificial groundwater recharge experiment was conducted in a pyroclastic plateau in Kagoshima Prefecture in Japan, and time-lapse electrical resistivity data were collected to monitor the recharge process. In the experiment, time-efficient in-line resistivity surveys were performed along four intersecting lines, because a large amount of water was released from two recharge areas and a relatively fast migration of water into the vadose zone was expected. The migration of recharged water may be estimated from changes in electrical resistivity because resistivity in the vadose zone is largely controlled by water saturation variations there. The geological setting at the experiment site was interpreted from the resistivity distribution inverted from the in-line survey data, which were obtained before the recharge experiment. The resistivity distribution showed an approximately layered structure, which could be correlated with four borehole logs in the area. Three-dimensional (3D) distributions of the resistivity change ratio were derived through constrained nonlinear ratio inversion. Three-dimensional inversion of the in-line resistivity data was more suitable than two-dimensional inversion to describe the 3D phenomena associated with groundwater recharge. During the recharge experiment, the zones of decreased resistivity shifted with time, indicating non-uniform penetration of water from the recharge areas into the ground and a horizontal flow of the recharged water, especially in the secondary Shirasu layer, which comprises lacustrine or marine sediments of pyroclastic origin. These interpretations agree with the variation in water content observed in a borehole.
The aim of this research was to delineate characteristic hydrogeological lake types in the Young Glacial Area (YGA). The YGA is in the central and east part of the Kashubian Lake District (KLD) in Northern Poland, an area covered by deposits of Quaternary glaciation. All the bigger lakes were investigated in the area of about 1500 km(2) (39 lakes). The role of lakes in groundwater recharge and discharge was determined from total dissolved solids (TDS) in lake waters and also from groundwater flow simulation. The general trend was that gaining lakes, as determined by flow modeling, had higher values of TDS than losing lakes. In addition to typical gaining lakes (with TDS > 250 mg/l), there were losing lakes perched on glacial till deposits with very low TDS (groundwater). Flow-through lakes with TDS of 170-200 mg/l were also delineated. © 2015, National Ground Water Association.
Importance of groundwater as a natural, renewable resource is well documented. The rate of replenishment of water table (or rate of groundwater recharge) is a key issue central to sustainable development of this valuable resource. Although many workers have used a soil water balance to estimate groundwater recharge, not many workers have investigated the effect of using different time steps (i.e. a day, 7 days etc.) in the water balance on the estimates of recharge. This study looks at the ef...
Kuroda, Keisuke; Hayashi, Takeshi; Do, An Thuan; Canh, Vu Duc; Nga, Tran Thi Viet; Funabiki, Ayako; Takizawa, Satoshi
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.
A. Shahul Hameed
New hydrological insights for the region: Based on the spatio-temporal variation in δ18O values of river and groundwater and fluctuation in ground water levels, following important inferences are made: (1 estimated river water contribution to post-monsoon groundwater recharge is ∼16% in the lowland coastal area of the Chaliyar river basin and 29% in midland region; (2 northeast winter monsoon rains contribute to the groundwater of Chaliyar river basin only in an insignificant manner, and with a delayed response; (3 unlike river water samples which exhibit both seasonal and spatial variation of more than 3‰, the groundwater samples vary only marginally (∼1‰ between the seasons and across the physiographic zones; (4 groundwater samples exhibit inverse altitude gradient in δ18O values in the highland zone, in all the three seasons. This may be due to flow of the isotopically depleted groundwater down the gradient and evaporation of residual water in the upper reaches of the basin.
Jordan F Clark
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 . 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.
Ke, Tingting; Shu, Longcang; Chen, Xunhong
The estimation of the groundwater recharge in a karstic system becomes an important challenge due to the great hydrodynamic variability in both time and space. This paper proposes a two reservoir conceptual model to simulate inflow into both the conduit system and the fissure network system based on the analysis of the spring hydrograph. The structure of the model and the governing equations are proposed on the basis of the physical considerations, with the assumption that flow at the outlet of the reservoirs obeys a linear threshold function. The model is applied on the Houzhai karstic underground river basin where it successfully reflects the temporal recharge distribution. The simulated accumulation recharge is 34.29 mm, which is reasonable in relation to the actual rainfall of 92.8 mm. The variations of water volume in two reservoirs represent the storage and transform characteristics of the karst aquifer system. However, this model is particularly well suited to simulate the recharge event after intensive rainfall.
Robertson, Wendy Marie; Böhlke, John Karl; Sharp, John M.
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.
Owuor, Steven; Butterbach-Bahl, Klaus; Guzha, Alphonce; Rufino, Mariana; Pelster, David; Díaz-Pinés, Eugenio; Breuer, Lutz; Merbold, Lutz
Conclusive evidence and understanding of the effects of land use and land cover (LULC) on both groundwater recharge and surface runoff is critical for effective management of water resources in semi-arid region as those heavily depend on groundwater resources. However, there is limited quantitative evidence on how changes to LULC in semi-arid tropical and subtropical regions affect the subsurface components of the hydrologic cycle, particularly groundwater recharge. In this study, we reviewed a total of 27 studies (2 modelling and 25 experimental), which reported on pre- and post-land use change groundwater recharge or surface runoff magnitude, and thus allowed to quantify the response of groundwater recharge rates and runoff to LULC. Restoration of bare land induces a decrease in groundwater recharge from 42 % of precipitation to between 6 and 12 % depending on the final LULC. If forests are cleared for rangelands, groundwater recharge increases by 7.8 ± 12.6 %, while conversion to cropland or grassland results in increases of 3.4 ± 2.5 and 4.4 ± 3.3 %, respectively. Rehabilitation of bare land to cropland results in surface runoff reductions of between 5.2 and 7.3 %. The conversion of forest vegetation to managed LULC shows an increase in surface runoff from 1 to 14.1 % depending on the final LULC. Surface runoff is reduced from 2.5 to 1.1 % when grassland is converted to forest vegetation. While there is general consistency in the results from the selected case studies, we conclude that there are few experimental studies that have been conducted in tropical and subtropical semi-arid regions, despite that many people rely heavily on groundwater for their livelihoods. Therefore, there is an urgent need to increase the body of quantitative evidence given the pressure of growing human population and climate change on water resources in the region.
Machiwal, Deepesh; Singh, P. K.; Yadav, K. K.
The present study determined aquifer parameters in hard-rock aquifer system of Ahar River catchment, Udaipur, India by conducting 19 pumping tests in large-diameter wells. Spreadsheet programs were developed for analyzing pumping test data, and their accuracy was evaluated by root mean square error (RMSE) and correlation coefficient ( R). Histograms and Shapiro-Wilk test indicated non-normality ( p value groundwater levels at 50 sites for years 2006-2008, and hence, logarithmic transformations were done. Furthermore, recharge was estimated using GIS-based water table fluctuation method. The groundwater levels were found to be influenced by the topography, presence of structural hills, density of pumping wells, and seasonal recharge. The results of the pumping tests revealed that the transmissivity ( T) ranges from 68-2239 m2/day, and the specific yield ( S y) varies from 0.211 to 0.51 × 10-5. The T and S y values were found reasonable for the hard-rock formations in the area, and the spreadsheet programs were found reliable (RMSE 0.017-0.339 m; R > 0.95). Distribution of the aquifer parameters and recharge indicated that the northern portion with high ground elevations (575-700 m MSL), and high S y (0.08-0.25) and T (>600 m2/day) values may act as recharge zone. The T and S y values revealed significant spatial variability, which suggests strong heterogeneity of the hard-rock aquifer system. Overall, the findings of this study are useful to formulate appropriate strategies for managing water resources in the area. Also, the developed spreadsheet programs may be used to analyze the pumping test data of large-diameter wells in other hard-rock regions of the world.
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
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.
Yenehun, Alemu; Walraevens, Kristine; Batelaan, Okke
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.
Montaldo, N.; Mancini, M.; Albertson, J. D.; Katul, G.
The structure and function of the vegetation regulates the exchange of mass, energy and momentum across the biosphere-atmosphere interface. Root systems affect soil properties, and vegetation density dominates the functioning of hydrological processes through modification of interception, infiltration, evapotranspiration, surface runoff, and groundwater recharge. Influencing the partitioning of incoming solar energy into sensible and latent heat fluxes, the changes in vegetation densities will result in long-term changes in both local and global climates (e.g., precipitation and temperature), and in turn will affect the vegetation growth as a feedback. In semi-arid regions, this may result in persistent drought and desertification, with substantial impacts on the human populations of these regions through reduction in agricultural productivity and reduction in quantity and quality of water supply. In these regions the water becomes a controlling factor, and the groundwater becomes an important water resource. We investigate the role of vegetation dynamics in the soil-vegetation-atmosphere system, and, in particular, on the groundwater recharge in a water-limited ecosystem. The questions addressed are: 1) how does groundwater recharge under grass differ from that under a tree canopy? 2) how does the recharge difference depend on the time scale over which precipitation variability or change occurs? 3) and, to what extent does “temporal change in leaf area” (i.e. denser vegetation in wetter periods) control the answers to the above questions? To reach the objectives, a coupled land surface model (LSM) and vegetation dynamics model is employed. The simple dynamic vegetation model simulates the plant growth, and provides the Leaf Area Index (LAI) evolution through time, which is then used by the LSM in the computation of the energy partitioning between soil and vegetation as well in the parameterization of turbulent transport and evapotranspiration. This updates the
Popp, Andrea; Kipfer, Rolf
Managed aquifer recharge (MAR) has become a common water management tool and serves various purposes such as improving the quality of groundwater (GW). At the study site, the Hardwald in Muttenz (Switzerland), MAR has been implemented in the mid-1950s to overcome increasing water demands. GW is artificially recharged with water from the river Rhine through a system of channels and ponds. The area is surrounded by potential contamination sites such as chemical industry, former landfills, a highway and a freight depot. Furthermore, the area shows a complex hydrogeologic setting with several fault zones and two main aquifers, the Quaternary Rhine gravel aquifer overlying a karstified Upper Muschelkalk limestone aquifer. Water from the deeper limestone aquifer is suspected to contain contaminants originating from the landfills. The fractures might serve as a hydraulic connection between the upper and lower aquifer. Further, groundwater pumping might enhance the mixing of recently infiltrated water with older water from the lower aquifer. Hence, the proximity to potential contamination sites and the complex geologic setting both pose risks for GW pollution and challenge the drinking water production in this area. To guarantee a safe drinking water supply, it is crucial to know the mixing patterns of young and old GW abstracted from the pumping wells. With this study we aim to determine the spatial variability of GW residence time distributions to differentiate between recently infiltrated river water and older groundwater. To reach our objectives, we use a combination of the following tracers to cover a wide range of possible GW ages: (1) radiogenic 222Rn (young water := age tracers. All parameters were analysed at 20 observation and pumping wells distributed throughout the study area. First results indicate that GW abstracted in the vicinity to the area with the highest recharge rates exhibits young water only. Wells further away from these high recharge areas contain
Full Text Available The groundwater flow system is typical dissipative structure system, and its evolution can be described with system information entropies. The information entropies of groundwater in Shijiazhuang City had been calculated between 1960 and 2005, and the results show that the entropies have a decreasing trend throughout the research period, and they can be divided into our stages based on the groundwater flow system entropy variation as follows: entropy steady period (1960–1965, entropy decreasing period (1965–1980, entropy increasing period (1980–1995 and secondary entropy decreasing period (1995–2005; understanding the major and significant driving the pattern changing forces of groundwater levels is essential to groundwater management,. A new method of grey correlation analysis has been presented, and the results show that, the grey correlation grade between groundwater flow system information entropies and precipitation series is γ01 = 0.749, the grey correlation grade between groundwater flow system information entropies and groundwater withdrawal series is γ02 = 0.814, as the groundwater withdrawal is the main driving force of groundwater flow system entropy variation; based on the numerical simulation results, information entropy increased with artificial recharge, and a smaller recharge water volume would enhance the information entropy drastically, but then doubled water would not increase the information correspondingly, which could be useful to assess the health state of groundwater flow systems.
Liliana Andrea Peñuela Arévalo
Full Text Available The aim of this paper is the delimitation of groundwater recharge and discharge zones in the centresouth portion of the Mesa Central. This was achieved using groundwater flow systems theory, which has proved to be a valuable tool since it considers a systemic perspective of the environment, integrating several natural elements. There are various physical, chemical and biological processes generated in the subsoil within which groundwater is incorporated. This involvement is caused by the natural gravitational movement of groundwater which is manifested on the surface by contrasting evidences in the recharge and discharge zones. Therefore, the objective of this paper includes the demonstration of the usefulness of the analysis of those indicators to locate priority areas and also provides an approximation of groundwater functioning. The definition of recharge and discharge zones included the analysis of maps describing soil type, vegetation, topographic elevation, groundwater flowpath direction, springs, and presence of natural water bodies. Such analysis was carried out through the overlaying tool of ArcMap™ software. The results suggest that the highlands of Fría, San Miguelito and Santa Bárbara as recharge zones. Natural discharge zones were originally present in the plain of the Aguascalientes tectonic depression, and some flat and topographic low zones in the vicinity of Altos de Jalisco, Santa María del Río and Ojuelos.
Coelho, Victor Hugo R.; Montenegro, Suzana; Almeida, Cristiano N.; Silva, Bernardo B.; Oliveira, Leidjane M.; Gusmão, Ana Cláudia V.; Freitas, Emerson S.; Montenegro, Abelardo A. A.
Data limitations on groundwater (GW) recharge over large areas are still a challenge for efficient water resource management, especially in semi-arid regions. Thus, this study seeks to integrate hydrological cycle variables from satellite imagery to estimate the spatial distribution of GW recharge in the Ipanema river basin (IRB), which is located in the State of Pernambuco in Northeast Brazil. Remote sensing data, including monthly maps (2011-2012) of rainfall, runoff and evapotranspiration, are used as input for the water balance method within Geographic Information Systems (GIS). Rainfall data are derived from the TRMM Multi-satellite Precipitation Analysis (TMPA) Version 7 (3B43V7) product and present the same monthly average temporal distributions from 15 rain gauges that are distributed over the study area (r = 0.93 and MAE = 12.7 mm), with annual average estimates of 894.3 (2011) and 300.7 mm (2012). The runoff from the Natural Resources Conservation Service (NRCS) method, which is based on regional soil information and Thematic Mapper (TM) sensor image, represents 29% of the TMPA rainfall that was observed across two years of study. Actual evapotranspiration data, which were provided by the SEBAL application of MODIS images, present annual averages of 1213 (2011) and 1067 (2012) mm. The water balance results reveal a large inter-annual difference in the IRB GW recharge, which is characterized by different rainfall regimes, with averages of 30.4 (2011) and 4.7 (2012) mm year-1. These recharges were mainly observed between January and July in regions with alluvial sediments and highly permeable soils. The GW recharge approach with remote sensing is compared to the WTF (Water Table Fluctuation) method, which is used in an area of alluvium in the IRB. The estimates from these two methods exhibit reliable annual agreement, with average values of 154.6 (WTF) and 124.6 (water balance) mm in 2011. These values correspond to 14.89 and 13.53% of the rainfall that was
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)
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
Rusteberg, Bernd; Azizur Rahman, M.; Abusaada, Muath; Rabi, Ayman; Rahman Tamimi, A.; Sauter, Martin
The water resources in Gaza Strip are currently facing extreme over-exploitation which has led to a sharp decline of the groundwater level in this Mediterranean coastal aquifer overtime. Salinity of the groundwater is very high as a result of subsequent seawater intrusion of the aquifer. The contamination of the Gaza Strip groundwater by seawater has wide-ranging effects on the regional economy as well as agricultural productivity. In order to guarantee the sustainability of regional development, which requires the access to clean water, groundwater artificial recharge (AR) is being considered as a potential solution to this current water resources problem. The objective of the present study is to analyze several strategies for the implementation and management of AR in Gaza Strip and their potential impacts on agriculture, environment, and the socio-economy. Based on the water policy on wastewater reclamation and reuse (Yr. 2005 - 2025), six AR management strategies were developed in close cooperation with the local stakeholder community. These scenarios take into consideration the development of the new North Gaza Wastewater Treatment Plant and were also judged with respect to a base-line scenario, otherwise known as the "Do Nothing Approach." Multi-Criteria Decision Analysis (MCDA) on ranking of the AR management scenarios was used. Twenty-one criteria ranging over a wide spectrum and four categories (Environmental, Public Health, Social, and Economical) were defined to ensure sound evaluation of each of the six AR management scenarios. A detailed geo-database was prepared to analyze all the related spatial, non-spatial, and temporal data. Socio-economic studies, field surveys, mathematical modeling, and GIS analysis were used for the criteria quantification. In the MCDA, Analytical Hierarchy Method (AHP) combined with weighted Linear Combination (WLC) and Composite Programming (CP) was employed. The six AR management strategies were thus compared to the "Do
Ahmadi, Mohammad Mehdi; Mahdavirad, Hadi; Bakhtiari, Bahram
Geographic information systems (GIS) and remote sensing techniques are used as a decision support system to identify potential soil aquifer treatment (SAT) sites for groundwater recharge of Kerman aquifer, which is located in the southeast of Iran. These sites are identified using a single-objective multi-criteria analysis. To ensure technical feasibility, environmental sustainability, social acceptability and economical viability a number of criteria are considered for the site selection. The criteria selected for the different variables and acceptable ranges are based on standards published in national and international guidelines and technical documents. Multi-criteria evaluation was performed combining all produced thematic maps by means of the weighted index overlay method in order to select sites meeting all the criteria. The resulting map of this analysis shows potential sites are located in the north, southwest and southeast of the study area. Considering field observations, a potential site, which is located in the southwest of the study area, is proposed as the most suitable site for SAT. The result indicates that the study area has sufficient required suitable space for groundwater recharge with treated wastewater.
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)
Izbicki, John A.; Johnson, Russell U.; Kulongoski, Justin T.; Predmore, Steven; Stonestrom, David A.; Constantz, Jim; Ferré, Ty P. A.; Leake, Stanley A.
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
Chen, Guoli; Liu, Xiang; Tartakevosky, Daniel; Li, Miao
Three fluoroquinolone antibiotics agents (FQs) in groundwater and reclaimed water have been investigated in Changzhou and Beijing, China. The occurrence of ofloxacin (OFL), enrofloxacin (ENR) and norfloxacin (NOR) is in nanograms per liter and has 100% frequency. The concentration order of FQs in reclaimed water is NOR>OFL>ENR, whilst the order in groundwater is NOR>ENR>OFL. And then the single and mixture adsorption-desorption have been studied and showed that (i) silty clay loam has higher sorption capacity than loamy sand, (ii) competitive adsorption exists when the three selected FQs coexist, (iii) ENR has a significantly priority sorption to NOR, whilst OFL has a least sorption among the mixture, (iv) there is no significant difference between the desorption results of mixture and the indivdual compound in relatively low concentration, (v) the formed chemical bonds and the irreversible combination of adsorption point are the significant influential factors for explaining desorption hysteresis of the selected FQs. Based on the above study, transport model and risk quotient have been performed, and the calculated risk quotient reveals that: (i) the selected FQs risk order in reclaimed water is OFL>ENR>NOR, (ii) in groundwater, OFL and ENR pose a higher risk than NOR no matter whether considering the long time groundwater recharge. This study will help policy makers to decide which FQs need to be covered in the priority substance lists defined in legislative frameworks. Copyright © 2016. Published by Elsevier Inc.
Moeck, Christian; Radny, Dirk; Auckenthaler, Adrian; Berg, Michael; Hollender, Juliane; Schirmer, Mario
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.
Wang, Jiale; Jin, Menggui; Lu, Guoping; Zhang, Dele; Kang, Fengxin; Jia, Baojie
Discharge-area groundwater in Jinan, a typical karst region in northern China, was investigated by studying both the hydrological and chemical processes evolving from the recharge in mountainous terrains to the karst-spring outflows in the metropolitan area. Large-scale exploitation of karst groundwater has led to a disturbing trend in the ever-decreasing spring outflow rates and groundwater level. There is insufficient information about the Jinan karst aquifers, which provide the main water sources to meet human demand and to sustain spring outflow. The coupling of hydrological and chemical processes quantifies the flow system through aqueous chemistry characterization of the water sources. This approach is used to study the groundwater flow discharges in different locations and geological settings. The potentiometric data indicated limited vertical connectivity between distinct hydrogeological units and alteration of the recharge regime by the faults and by artificial exploitation. Shallow groundwater primarily belongs to the local flow system, with high nitrate concentration and enriched stable isotopic contents. Thermal groundwater has high concentrations of chloride and total dissolved solids, derived from a regional flow system with the highest recharge altitudes and long residence time. Non-thermal karst water may be attributed to the intermediate flow system, with uniform HCO3-Ca(Mg) facies and low nitrate concentration. This work highlighted discharge as a fingerprint of groundwater flow conditions and provides a better insight into the hydrogeological system.
Hou, Lizhu; Wang, Xu-Sheng; Hu, Bill X.; Shang, Jie; Wan, Li
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.
Drexler, Judith Z.; Knifong, Donna L.; JayLee Tuil,; Flint, Lorraine E.; Flint, Alan L.
Currently, little is known about the impact of climate change on groundwater recharge in the Sierra Nevada and southern Cascade Range of California or other mountainous regions of the world. The purpose of this study was to determine whether small alpine peat lands called fens can be used as whole-ecosystem gauges of groundwater recharge through time. Fens are sustained by groundwater discharge and are highly sensitive to changes in groundwater flow due to hydrologic disturbance including climate change. Seven fens in the Sierra Nevada and southern Cascade Range were studied over a 50-80 year period using historic aerial photography. In each aerial photograph, fen areas were identified as open lawn and partially treed areas that exhibited (1) dark brownish-green coloring or various shades of gray and black in black and white imagery and (2) mottling of colors and clustering of vegetation, which signified a distinct moss canopy with overlying clumped sedge vegetation. In addition to the aerial photography study, a climate analysis for the study sites was carried out using both measured data (U.S. Department of Agriculture Natural Resources Conservation Service SNOwpack TELemetry system) and modeled data (a downscaled version of the Parameter-elevation Regressions on Independent Slopes Model) for the period from 1951 to 2010. Over the study period, the five fens in the Sierra Nevada were found to be decreasing between 10% and 16% in delineated area. The climate analysis revealed significant increases through time in annual mean minimum temperature (Tmin) between 1951-1980 and 1981-2010. In addition, April 1 snow water equivalent and snowpack longevity also decreased between 1951-1980 and 1981-2010. For the fens in the Cascade Range, there were no discernible changes in delineated area. At these sites, increases in Tmin occurred only within the past 20-25 years and decreases in snowpack longevity were more subtle. A conceptual model is presented, which illustrates
Verbeiren, Boud; Weerasinghe, Imeshi; Vanderhaegen, Sven; Canters, Frank; Uljee, Inge; Engelen, Guy; Jacquemin, Ingrid; Tychon, Bernard; Vangelis, Harris; Tsakiris, George; Batelaan, Okke; Huysmans, Marijke
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
Gao, Yu-Tuan; Zhang, Xue; Zhao, Xuan; Zhao, Gang
To prevent groundwater contamination, pretreatments of reclaimed water are needed before the groundwater recharge. In this study, five treatments, including ultrafiltration (UF), ozonation, magnetic ion exchange (MIEX), UF coupled with ozonation and MIEX coupled with ozonation, were evaluated for their purification efficiencies of the reclaimed water and their influences on the following soil aquifer treatments. For organic matters in the secondary effluents, identified as dissolved organic carbon (DOC) and specific ultraviolet absorbance (SUVA), 20% DOC and 10% SUVA are removed by MIEX treatment with dose of 5 mL x L(-1), while only 10% DOC and no SUVA are removed by UF, but neither of these two pretreatments enhance the purification of soil aquifer treatments. Differently, SUVA of the secondary effluents are removed by 60%-79% by ozonation alone or coupled with UF/MIEX, increasing the biodegradability of the reclaimed water. These pretreatments significantly enhance the removal of organic matters by the following soil aquifer with DOC in the final effluents reducing to 1-2 mg x L(-1). For nitrogen, MIEX can remove 25% NO3(-) -N, and ozonation can remove 72% NH4(+) -N. The soil aquifer treatment could efficiently remove NH4(+) -N to below 0.5 mg x L(-1), while no obvious removal is detected for NO3(-) -N. In conclusion, more attentions should be paid to the organic matters and NO3(-) -N during the pretreatments of reclaimed water. Among all the pretreatments tested here, ozonation coupled with MIEX is capable of increasing the biodegradability of the reclaimed water and removing NO3(-) -N, which is a good choice for the pretreatment of groundwater recharge.
Ronen-Eliraz, Gefen; Russak, Amos; Nitzan, Ido; Guttman, Joseph; Kurtzman, Daniel
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.
Sahoo, Sasmita; Jha, Madan K.
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.
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
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
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.
Phillips, S.P.; Hamlin, S.N.; Yates, E.B.
The city of San Francisco is considering further development of local groundwater resources as a supplemental source of water for potable or nonpotable use. By the year 2010, further water demand is projected to exceed the delivery capacity of the existing supply system, which is fed by surface-water sources; thus supplies are susceptible to drought conditions and damage to conveyance lines by earthquakes. The primary purpose of this study is to describe local geohydrology and water quality and to estimate groundwater recharge in the area of the city of San Francisco. Seven groundwater basins were identified in San Francisco on the basis of geologic and geophysical data. Basins on the east side of the city are relatively thin and contain a greater percentage of fine-grained sediments than those on the west side. The relatively small capacity of the basins and greater potential for contamination from sewer sources may limit the potential for groundwater development on the east side. Basins on the west side of the city have a relatively large capacity and low density sewer network. Water-level data indicate that the southern part of the largest basin on the west side of the city (Westside basin) probably cannot accommodate additional groundwater development without adversely affecting water levels and water quality in Lake Merced; however, the remainder of the basin, which is largely undeveloped, could be developed further. A hydrologic routing model was developed for estimating groundwater recharge throughout San Francisco. The model takes into account climatic factors, land and water use, irrigation, leakage from underground pipes, rainfall runoff, evapotranspiration, and other factors associated with an urban environment. Results indicate that area recharge rates for water years 1987-88 for the 7 groundwater basins ranged from 0.32 to 0.78 feet per year. Recharge for the Westside basin was estimated at 0.51 feet per year. Average annual groundwater recharge
Sahu, Paulami; Michael, Holly A.; Voss, Clifford I.; Sikdar, Pradip K.
Water supply to the world's megacities is a problem of quantity and quality that will be a priority in the coming decades. Heavy pumping of groundwater beneath these urban centres, particularly in regions with low natural topographic gradients, such as deltas and floodplains, can fundamentally alter the hydrological system. These changes affect recharge area locations, which may shift closer to the city centre than before development, thereby increasing the potential for contamination. Hydrogeological simulation analysis allows evaluation of the impact on past, present and future pumping for the region of Kolkata, India, on recharge area locations in an aquifer that supplies water to over 13 million people. Relocated recharge areas are compared with known surface contamination sources, with a focus on sustainable management of this urban groundwater resource. The study highlights the impacts of pumping on water sources for long-term development of stressed city aquifers and for future water supply in deltaic and floodplain regions of the world.
Bjerklie, David M.; Viger, Roland; Trombley, Thomas J.
A regional watershed model was developed for watersheds contributing to Long Island Sound, including the Connecticut River basin. The study region covers approximately 40 900 km2, extending from a moderate coastal climate zone in the south to a mountainous northern New England climate zone dominated by snowmelt in the north. The input data indicate that precipitation and temperature have been increasing for the last 46 years (1961– 2006) across the region. Minimum temperature has increased more than maximum temperature over the same period (1961–2006). The model simulation indicates that there was an upward trend in groundwater recharge across most of the modeled region. However, trends in increasing precipitation and groundwater recharge are not significant at the 0.05 level if the drought of 1961–67 is removed from the time series. The trend in simulated snowfall is not significant across much of the region, although there is a significant downward trend in southeast Connecticut and in central Massachusetts. To simulate future trends, two input datasets, one assuming high carbon emissions and one assuming low carbon emissions, were developed from GCM forecasts. Under both of the carbon emission scenarios, simulations indicate that historical trends will continue, with increases in groundwater recharge over much of the region and substantial snowfall decreases across Massachusetts, Connecticut, southern Vermont, and southern New Hampshire. The increases in groundwater recharge and decreases in snowfall are most pronounced for the high emission scenario.
Pool, D. R.
Repeat microgravity surveys are being used in arid and semiarid regions to better define ground-water budgets and estimate specific yield. Repeated measurements at single stations or networks of stations are differenced to determine gravity change. Gravity change across a network of stations is integrated to estimate change in total mass and ground-water storage. Calculations are based on the assumption that there are no significant non-ground-water sources of mass change, such as movement of magma. Specific yield values can be estimated at observation-well sites where water-level and gravity changes are correlated. Ground-water budget components of inflow (recharge), outflow, and storage change are commonly uncertain. Rarely is any one component completely defined by measurement. Only outflow at discrete locations, such as wells and streams, can readily be measured. Inflow is difficult to measure because it is normally dispersed across large areas and occurs episodically. Storage change is normally calculated as a residual of outflow and inflow, and includes all of the uncertainties the other components. Ground-water budgets in heavily developed arid and semiarid basins are commonly dominated by storage change. Gravity methods can be used to estimate change, often leaving a single unknown, recharge, that can be estimated as a residual of measured or estimated outflow and storage change. Four types of gravity instruments are currently being used to measure changes in the distribution of mass on the Earth including: absolute meters, relative meters, super-conducting meters, and satellites. Modern absolute meters use lasers and precise clocks to measure the rate of fall of a mass in a vacuum. Relative meters use a very sensitive spring to measure differences in the force of gravity among sites. Super-conducting meters monitor the strength of a magnetic field necessary to levitate a mass against the changing gravity field. Variations in satellite orbits are also a
Wu, Linlin; Zhao, Xuan; Zhang, Meng
A novel process, enhanced direct injection-well recharge system (EnDir), can overcome the technical difficulties during the application of conventional surface spreading and has been developed to recharge groundwater with reclaimed water. In this study, removal and transformation of dissolved organic matter (DOM) in the system were investigated in laboratory-scale experiments. Results demonstrated that dissolved organic carbon and trihalomethane formation potential values could be reduced from 6.54 +/- 1.30 mg/L and 267.9 +/- 24.3 microg/L to 1.59 +/- 0.64 mg/L and 104.5 +/- 10.2 microg/L, respectively, as a result of DOM biodegradation in the aerobic short-term vadose soil treatment. Fluorescence spectra showed that aromatic protein-like substances and soluble microbial byproducts could be removed, to a great extent, in the soil system. Despite different removal efficiencies of DOM in different molecular weight fractions, the residual DOM was composed mainly of fulvic acid-like and humic acid-like substances, with molecular weights of 500 Da to 1 kDa.
Panno, Samuel V; Askari, Zohreh; Kelly, Walton R; Parris, Thomas M; Hackley, Keith C
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.
A. Vallet; Bertrand, C.; Fabbri, O.; Mudry, J.
Pore water pressure built-up by recharge of underground hydrosystems is one of the main triggering factors of deep-seated landslides. Groundwater recharge, which is the contribution of the precipitation to the recharge of the saturated zone, is a significant parameter. However, in landslide studies, methods and recharge area parameters used to determine the groundwater recharge amount are rarely detailed. Currently, no turnkey method has been proposed to simply and ac...
Cresswell, Richard; Wischusen, John; Jacobson, Gerry; Fifield, Keith
The sustainability of community water supplies drawn from shallow aquifers in the arid southwest of the Northern Territory has been evaluated using the radioactive isotope chlorine-36 (36Cl). These aquifers include fractured sandstones of the Ngalia Basin, fractured metamorphic rocks and Cainozoic sands and gravels. 36Cl/Cl ratios for these shallow, regional groundwaters exhibit a bimodal distribution with peaks at 205 (±7) and 170 (±7)×10-15. The higher ratio probably represents modern (Holocene) recharge, diluted with windblown salts from local playa lakes, and occurs mostly around the margin of the basin. The lower ratio corresponds to a 36Cl "age", or mean residence time, of 80-100 ka, implying that the last major recharge occurred during the last interglacial interval (Oxygen Isotope Stage 5). These values are mainly observed in the interior of the Ngalia Basin. Lower values of the 36Cl/Cl ratio measured near playa lakes are affected by addition of chloride from remobilised salts. Finite carbon-14 (14C) data for the groundwaters are at variance with the 36Cl results, but a depth profile suggests low recharge, allowing diffusion of recent atmospheric carbon to the water table. The 36Cl results have important implications for groundwater management in this region, with substantial recharge only occurring during favourable, wet, interglacial climatic regimes; most community water supplies are dependent on these "old" waters.
Losjoe, K.; Johansson, Barbro; Bringfelt, B.; Oleskog, I.; Bergstroem, S. [Swedish Meteorological and Hydrological Inst., Norrkoeping (Sweden)
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
King, Adam C.; Raiber, Matthias; Cox, Malcolm E.; Cendón, Dioni I.
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.
Ali Rahmani, S. E.; Chibane, Brahim; Boucefiène, Abdelkader
Deficiency of surface water resources in semi-arid area makes the groundwater the most preferred resource to assure population increased needs. In this research we are going to quantify the rate of groundwater recharge using new hybrid model tack in interest the annual rainfall and the average annual temperature and the geological characteristics of the area. This hybrid model was tested and calibrated using a chemical tracer method called Chloride mass balance method (CMB). This hybrid model is a combination between general hydrogeological model and a hydrological model. We have tested this model in an aquifer complex in the region of Djelfa (Algeria). Performance of this model was verified by five criteria [Nash, mean absolute error (MAE), Root mean square error (RMSE), the coefficient of determination and the arithmetic mean error (AME)]. These new approximations facilitate the groundwater management in semi-arid areas; this model is a perfection and amelioration of the model developed by Chibane et al. This model gives a very interesting result, with low uncertainty. A new recharge class diagram was established by our model to get rapidly and quickly the groundwater recharge value for any area in semi-arid region, using temperature and rainfall.
Kuss, A. M.; Gurdak, J. J.
Climate variability on interannual to multidecadal temporal scales has substantial implications for management and sustainability of water resources, yet are poorly understood throughout much of the United States. Climate forcings on these timescales partially control precipitation distribution, temperature fluctuations, drought occurrence and severity, streamflow, and recharge. Reliable predictions of future climate and subsequent adaptation of groundwater management strategies in vulnerable aquifers, such as the Central Valley aquifer located in central California of the United States, requires improved understanding of climate variability on interannual to multidecadal timescales and the associated responses in recharge rates. Groundwater withdrawals from the Central Valley aquifer are the second largest of all aquifers in the United States and are used to support one of the largest agricultural economies. However, the effects of the El Niño Southern Oscillation (ENSO) (2 to 6 year cycle), Pacific Decadal Oscillation (PDO) (10 to 25 year cycle), and Atlantic Multidecadal Oscillation (AMO) (50 to 80 year cycle) on recharge rates and groundwater levels in the Central Valley aquifer previously have not been quantified. In this study, singular spectrum analysis (SSA) was used to identify the principal components of groundwater level time series from selected wells in Central Valley aquifer that contribute to the greatest amount of variance in the record. In each of the time series analyzed, the PDO was the most significant contributor to groundwater level fluctuations. Wavelet analysis was also used to examine the nonstationary phase relation of multiple time series to identify significance and duration of each forcing. A consistent phase relation of multiple signals suggests possible coherence between climate forcings and groundwater levels, and also indicates the effect of the PDO on groundwater levels. These findings support the conclusion that interannual to
Siade, Adam; Nishikawa, Tracy; Martin, Peter
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.
Siade, Adam J.; Nishikawa, Tracy; Martin, Peter
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.
Zlotnik, V. A.; Noel, P.; Kacimov, A. R.; Al Maktoumi, A. K.
Many areas of the world (e.g. the Middle East and North Africa countries) are deficient in observation networks and hydrogeological data needed for Managed Aquifer Recharge (MAR) design. Therefore, diagnostic analytical approaches are appropriate for feasibility studies of MAR. It was found that the common assumption of aquifer thickness uniformity often does not hold, especially in mountainous watersheds. However, the only practical result available for non-uniform aquifers was developed for well hydraulics applications (point sinks or sources) by Hantush (1962), while the recharge zones may cover large areas on the scale of kilometers, such as temporarily filled impoundments (natural and engineered reservoirs in wadis, depressions, trenches, etc.) or perennial streams accepting massive treated wastewater discharge. To address these important, but overlooked MAR problems in sloping aquifers, a set of new closed-form analytical solutions for water table elevations were obtained. Interestingly, the 2D groundwater flow equation acquires the advection-dispersion equation form in these cases. The quadratures in closed-form solutions obtained by the Green's function method converge rapidly. These models account for both shapes and orientations of sources with respect to the direction of the aquifer base gradient. Qualitatively, solutions in sloping aquifers have an important trait: the mounding is limited in time and space, unlike in aquifers with a horizontal base. Aquifers with the greater slopes have the lesser potential of waterlogging from the rising water table and different storage characteristics (height and volume of locally stored water). Computational aspects of these solutions for MAR analyses are illustrated by example utilizing regional aquifer properties near Az Zarqa River, Jordan. (This study was supported by a grant from USAID-FABRI, project contract: AID-OAA-TO-11-00049, Subcontract: 1001624 -12S-19745).
U.S. Geological Survey, Department of the Interior — This tabular data set represents the mean annual natural groundwater recharge, in millimeters, compiled for every MRB_E2RF1catchment of selected Major River Basins...
Kolbe, T.; Abbott, B. W.; Marçais, J.; Thomas, Z.; Aquilina, L.; Labasque, T.; Pinay, G.; De Dreuzy, J. R.
Groundwater transit time and flow path are key factors controlling nitrogen retention and removal capacity at the catchment scale (Abbott et al., 2016), but the relative importance of hydrogeological and topographical factors in determining these parameters remains uncertain (Kolbe et al., 2016). To address this unknown, we used numerical modelling techniques calibrated with CFC groundwater age data to quantify transit time and flow path in an unconfined aquifer in Brittany, France. We assessed the relative importance of parameters (aquifer depth, porosity, arrangement of geological layers, and permeability profile), hydrology (recharge rate), and topography in determining characteristic flow distances (Leray et al., 2016). We found that groundwater flow was highly local (mean travel distance of 350 m) but also relatively old (mean CFC age of 40 years). Sensitivity analysis revealed that groundwater travel distances were not sensitive to geological parameters within the constraints of the CFC age data. However, circulation was sensitive to topography in lowland areas where the groundwater table was close to the land surface, and to recharge rate in upland areas where water input modulated the free surface of the aquifer. We quantified these differences with a local groundwater ratio (rGW-LOCAL) defined as the mean groundwater travel distance divided by the equivalent surface distance water would have traveled along the land surface. Lowland rGW-LOCAL was near 1, indicating primarily topographic controls. Upland rGW-LOCALwas 1.6, meaning the groundwater recharge area was substantially larger than the topographically-defined catchment. This ratio was applied to other catchments in Brittany to test its relevance in comparing controls on groundwater circulation within and among catchments. REFERENCES Abbott et al., 2016, Using multi-tracer inference to move beyond single-catchment ecohydrology. Earth-Science Reviews. Kolbe et al., 2016, Coupling 3D groundwater modeling
Hoffmann, John P.; Leake, Stanley A.
A local ground-water flow model is used to simulate four recharge scenarios along Rillito Creek in northern Tucson to evaluate mitigating effects on ground-water deficits and water-level declines in Tucson's Central Well Field. The local model, which derives boundary conditions from a basin-scale model, spans the 12-mile reach of Rillito Creek and extends 9 miles south into the Central Well Field. Recharge scenarios along Rillito Creek range from 5,000 to 60,000 acre-feet per year and are simulated to begin in 2005 and extend through 2225 to estimate long-term changes in ground-water level, ground-water storage, ground-water flux, and evapotranspiration. The base case for comparison of simulated water levels and flows, referred to as scenario A, uses a long-term recharge rate of 5,000 acre-feet per year to 2225. Scenario B, which increases the recharge along Rillito Creek by 9,500 acre-feet per year, has simulated water-level rises beneath Rillito Creek that range from about 53 feet to 86 feet. Water-level rises within the Central Well Field range from about 60 feet to 80 feet. More than half of these rises occur by 2050, and more than 95 percent occur by 2188. Scenario C, which increases the recharge along Rillito Creek by 16,700 acre-feet per year relative to scenario A, has simulated water-level rises beneath Rillito Creek that range from about 71 feet to 102 feet. Water-level rises within the Central Well Field range from about 80 feet to 95 feet. More than half of the rises occur by 2036, and more than 95 percent occur by 2100. Scenario D, which initially increases the recharge rate by about 55,000 acre-feet per year relative to scenario A, resulted in simulated water levels that rise to land surface along Rillito Creek. This rise in water level resulted in rejected recharge. As the water table continued to rise, the area of stream-channel surface intersected by the water table increased causing continual decline in the recharge rate until a long-term recharge
Cuthbert, M. O.; Mackay, R.; Tellam, J. H.; Thatcher, K. E.
SummaryAlthough there has been much previous research into various aspects of the flow mechanisms through glacial till, an integrated analysis of the flow system from the ground surface to the aquifer is lacking. This paper describes such an approach with reference to a detailed field study of the hydraulic processes controlling groundwater recharge through lodgement till in Shropshire, UK. A fieldsite was instrumented with tensiometers and piezometers at a range of depths through the profile, and the geology investigated in detail through field and laboratory testing. The median matrix hydraulic conductivity of the 6 m thick till is found to be around 2 × 10 -10 m/s on the basis of laboratory measurements. Using the barometric efficiency of the till derived from on-site pressure responses, the specific storage for the till is found to be in the range 2 × 10 -6-6 × 10 -6 m -1 and approximately 3 × 10 -6 m -1 for the underlying Permo-Triassic sandstone, the regional aquifer. The hydraulic data indicate that till water table responses to rainfall occur during the summer period even when large tensions are present higher in the profile. This is thought to be due to preferential flow through hydraulically active fractures in the till, which were observed in a test pit dug on-site. The field evidence indicates that the fractures are usually infilled with a variety of materials derived and transported from clasts within the till. The bulk hydraulic conductivity of the till seems to be greatly enhanced by these features and it is shown on the basis of hydraulic testing and numerical modelling that the bulk hydraulic conductivity of the till is orders of magnitude greater than that of the till matrix and reduces with depth below ground surface. The paper furthers understanding of the hydraulic processes contributing to recharge through till and makes the link between the detail of these processes and simplified models of recharge estimation, which may be needed for
Verhoef, Anne; Cook, Peter; Black, Emily; Macdonald, David; Sorensen, James
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.
Sarrazin, F.; Hartmann, A. J.; Pianosi, F.; Wagener, T.
Preferential flow (concentrated flow in areas of higher hydraulic conductivities) can occur in the soil and in the underlying bedrock due to root channels, heterogeneities in soil composition, physical and chemical weathering, and cracks and fissures in the bedrock originating from tectonic processes. It strongly influences groundwater recharge magnitude and dynamics. In particular, karst systems, which develop from the dissolution of carbonate rocks, include large fractures and conduits with high permeability. Karst aquifers are an important source of drinking water in many regions of the world but their resources are likely to be affected by changes in climate and land cover/land use. Therefore, understanding karst hydrology and estimating karst groundwater recharge at a large-scale is critical for preventing threats to water supply in a changing world. Hartmann et al. (2015, Geosci. Model Dev.) introduced a parsimonious karst recharge model, called VarKarst-R, which allows for large-scale simulations of groundwater recharge while accounting for the process of flow concentration in preferential pathways. The first objective of the present study is to introduce vegetation processes into the VarKarst-R model to better estimate evapotranspiration losses depending on land cover characteristics. We test the model at FLUXNET sites located in carbonate rock areas. Secondly, we establish a sensitivity analysis framework to understand the interactions between climate descriptors (e.g. mean precipitation, precipitation seasonality), vegetation parameters (e.g. canopy storage capacity, rooting depth) and soil parameters (e.g. soil storage, flow concentration coefficient). We apply this framework and the modified VarKarst-R model to assess the relative influence of changes in climate and land cover on aquifer recharge in Europe and in Mediterranean carbonate rock areas.
Ma, Weifang; Nie, Chao; Chen, Bin; Cheng, Xiang; Lun, Xiaoxiu; Zeng, Fangang
Endocrine disrupting chemical (EDC) pollution in river-based artificial groundwater recharge using reclaimed municipal wastewater poses a potential threat to groundwater-based drinking water supplies in Beijing, China. Lab-scale leaching column experiments simulating recharge were conducted to study the adsorption, biodegradation, and transport characteristics of three selected EDCs: 17β-estradiol (E2), 17α-ethinylestradiol (EE2) and bisphenol A (BPA). The three recharge columns were operated under the conditions of continual sterilization recharge (CSR), continual recharge (CR), and wetting and drying alternative recharge (WDAR). The results showed that the attenuation effect of the EDCs was in the order of WDAR>CR>CSR system and E2>EE2>BPA, which followed first-order kinetics. The EDC attenuation rate constants were 0.0783, 0.0505, and 0.0479 m(-1) for E2, EE2 and BPA in the CR system, respectively. The removal rates of E2, EE2, and BPA in the CR system were 98%, 96% and 92%, which mainly depended on biodegradation and were affected by water temperature. In the CR system, the concentrations of BPA, EE2, and E2 in soil were 4, 6 and 10 times higher than in the WDAR system, respectively. According to the DGGE fingerprints, the bacterial community in the bottom layer was more diverse than in the upper layer, which was related to the EDC concentrations in the water-soil system. The dominant group was found to be proteobacteria, including Betaproteobacteria and Alphaproteobacteria, suggesting that these microbes might play an important role in EDC degradation. Copyright © 2015. Published by Elsevier B.V.
Dripps, W. R.; Anderson, M. P.; Hunt, R. J.
It has long been recognized that infiltration influences the vertical subsurface temperature profile. Many researchers have used changes in the temperature profile to quantify the rate of groundwater flow in saturated systems, e.g. in wetlands and streambeds. Others have considered coupled heat and flow transport through the unsaturated zone, but we are aware of only two groups (Taniguchi and Sharma, 1993; Tabbagh et al., 1999) who have previously used temperature profiles through the unsaturated zone to estimate rates of areally extensive groundwater recharge. Both groups looked at seasonal changes in soil temperature to estimate annual recharge rates, but no attempt was made to analyze individual recharge events. We collected hourly soil temperature measurements through the unsaturated zone at depths of 0.05, 0.2, 0.5, 1, and 3 meters at a site in the Trout Lake basin of northern Wisconsin for the past two years. VS2DH (Healy and Ronan, 1996), a two-dimensional, numerical, coupled heat and water flow model for variably saturated media, was used to simulate the thermocouple data and estimate rates of recharge for individual recharge events. Field studies including Guelph permeameter tests, slug tests, grain size analyses, bulk density estimates, and lab measurements of soil moisture characteristic curves were used to estimate the necessary hydraulic and thermal parameters for the model. The field data were supplemented by values reported in the literature, and further refined during model calibration. Recharge rates computed using temperature data were compared with estimates based on water level fluctuations and estimates obtained using simple water balance modeling.
Timuhins, A.; Klints, I.; Sennikovs, J.; Virbulis, J.
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
Gette-Bouvarot, Morgane; Volatier, Laurence; Lassabatere, Laurent; Lemoine, Damien; Simon, Laurent; Delolme, Cécile; Mermillod-Blondin, Florian
Infiltration systems are increasingly used in urban areas for groundwater recharge. The reduction of sediment permeability by physical and/or biological processes is a major problem in management of infiltration systems often requiring expensive engineering operations for hydraulic performance maintenance. To reduce these costs and for the sake of sustainable development, we proposed to evaluate the ability of ecological engineering approaches to reduce the biological clogging of infiltration basins. A 36-day field-scale experiment using enclosures was performed to test the influences of abiotic (light reduction by shading) and biotic (introduction of the macrophyte Vallisneria spiralis (L.) or the gastropod Viviparus viviparus (Linnaeus, 1758)) treatments to limit benthic biofilm biomass and to maintain or even increase hydraulic performances. We coupled biological characterization of sediment (algal biomass, bacterial abundance, total organic carbon, total nitrogen, microbial enzymatic activity, photosynthetic activity, and photosystem II efficiency) with hydraulic conductivity measurements to assess the effects of treatments on sediment permeability. The grazer Viviparus viviparus significantly reduced benthic biofilm biomass and enhanced hydraulic conductivity. The other treatments did not produce significant changes in hydraulic conductivity although Vallisneria spiralis affected photosynthetic activity of biofilm. Finally, our results obtained with Viviparus viviparus are promising for the development of ecological engineering solutions to prevent biological fouling in infiltration systems.
Barba Ferrer, Carme; Folch, Albert; Gaju, Núria; Martínez-Alonso, Maira; Carrasquilla, Marc; Grau-Martínez, Alba; Sanchez-Vila, Xavier
Managed Artificial Recharge (MAR) represents a strategic tool for managing water resources, especially during scarce periods. On one hand, it can increase water stored in aquifers and extract it when weather conditions do not permit exclusive exploitation of surface resources. On the other, it allows improve water quality due the processes occurring into the soil whereas water crosses vadose zone. Barcelona (Catalonia, Spain) conurbation is suffering significant quantitative and qualitative groundwater disturbances. For this reason, Sant Vicenç MAR system, constituted by a sedimentation and an infiltration pond, was constructed in 2009 as the strategic water management infrastructure. Compared with other MAR facilities, this infiltration pond has a reactive bed formed by organic compost and local material. The objective is to promote different redox states allowing more and different degradation of chemical compounds than regular MAR systems. In previous studies in the site, physical and hydrochemical parameters demonstrated that there was indeed a degradation of different pollutants. However, to go a step further understanding the different biogeochemical processes and the related degradation processes occurring in the system, we studied the existing microbial communities. So, molecular techniques were applied in water and soil samples in two different scenarios; the first one, when the system was fully operating and the second when the system was not operating during some months. We have specifically compared microbial diversity and richness indexes and both cluster dendrograms obtained from DGGEs analysis made in each sampling campaign.
O'Leary, David; Izbicki, John; T.J. Kim,; Clark Ajawani,; Suarez, Donald; Barnes, Thomas; Thomas Kulp,; Burgess, Matthew K.; Tseng, Iwen
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
Hopkins, Candice B.
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.
Müller, Th.; Osenbrück, K.; Strauch, G.; Pavetich, S.; Al-Mashaikhi, K.-S.; Herb, C.; Merchel, S.; Rugel, G.; Aeschbach, W.; Sanford, Ward E.
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 recharge area in the Dhofar Mountains, > 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.
Hornero, Jorge; Manzano, Marisol; Ortega, Lucía; Custodio, Emilio
Groundwater recharge is one of the key variables for aquifer management and also one of the most difficult to be evaluated with acceptable accuracy. This is especially relevant in semiarid areas, where the processes involved in recharge are widely variable. Uncertainty should be estimated to know how reliable recharge estimations are. Groundwater recharge has been calculated in the Alcadozo Aquifer System, under steady state conditions, at regional (aquifer) and sub-regional (spring catchment) scales applying different methods. The regional distribution of long-term average recharge values has been estimated with the chloride mass balance method using data from four rain stations and 40 groundwater samples covering almost the whole aquifer surface. A remarkable spatial variability has been found. Average annual recharge rates ranges from 20 to 243mmyear(-1) across the aquifer, with an estimated coefficient of variation between 0.16 and 0.38. The average recharge/precipitation ratio decreases from 34% in the NW to 6% in the SE, following the topographic slope. At spring-catchment scale, recharge has been estimated by modelling the soil water balance with the code Visual Balan 2.0. The results, calibrated with discharge data of the two main springs Liétor and Ayna, are 35.5 and 50mmyear(-1) respectively, with estimated coefficients of variation of 0.49 and 0.36. A sensitivity analysis showed that soil parameters influence the most the uncertainty of recharge estimations. Recharge values estimated with both methods and at two temporal and spatial scales are consistent, considering the regional variability obtained with the chloride method and the respective confidence intervals. Evaluating the uncertainties of each method eased to compare their relative results and to check their agreement, which provided confidence to the values obtained. Thus, the use of independent methods together with their uncertainties is strongly recommended to constrain the magnitude and to
Chen, Ching-Nuo; Tsai, Chih-Heng
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
Tiwari, Ashwani Kumar; Lavy, Muriel; Amanzio, Gianpiero; De Maio, Marina; Singh, Prasoon Kumar; Mahato, Mukesh Kumar
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.
Tiwari, Ashwani Kumar; Lavy, Muriel; Amanzio, Gianpiero; De Maio, Marina; Singh, Prasoon Kumar; Mahato, Mukesh Kumar
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.
Cifuentes, Enrique; Suárez, Leticia; Espinosa, Martha; Juárez-Figueroa, Luis; Martínez-Palomo, Adolfo
The objective of this study was to assess the risk of infection with Giardia intestinalis in children living in an area with artificial groundwater recharge and potable water reuse in Mexico City. Eligible wells and surrounding homesteads were defined by using a geographic information system. Five wells were tested for G. intestinalis cysts per 400 liters of water. A total of 750 eligible households were visited during two cross-sectional surveys. Stool samples were provided by 986 children in the rainy season study and 928 children during the dry season survey for parasitologic tests. Their guardians provided information on water, sanitation, hygiene, and socioeconomic variables. The prevalence rates of G. intestinalis infection were 9.4% in the rainy season and 4.4% in the dry season. Higher rates of infection were observed in older individuals (9.5% and 10.6%) and girls had a lower risk of infection than boys (odds ratio [OR] =0.55, 95% confidence interval [CI] = 0.34, 0.88 in the rainy season and OR = 0.47, 95% CI = 0.25, 0.90 in the dry season). During the wet season survey, a health risk was detected among those storing water in unprotected receptacles (OR = 4.00, 4.69, and 5.34 for those using uncovered jars, cisterns or tanks, and buckets, respectively), and bathing outside the dwelling, i.e., using a tap (OR = 1.93, 95% CI = 1.10, 3.39). A health risk was also detected among children from households with unsafe food hygiene practices (OR =2.41, 95% CI =1.10, 5.30) and those with no hand-washing habits (OR = 2.27, 95% CI = 1.00, 5.20). Groundwater reserves are at risk of fecal pollution, as indicated by the presence of G. intestinalis cysts. However, the endemic pattern of intestinal infection reflects low standards of personal hygiene and unsafe drinking water storage and food-related practices at household level. Prevention activities must address health education and environmental protection policies.
Mindl, Birgit; Hofer, Julia; Kellermann, Claudia; Stichler, Willibald; Teichmann, Günter; Psenner, Roland; Danielopol, Dan L; Neudorfer, Wolfgang; Griebler, Christian
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.
Fryar, Alan; Mullican, William; Macko, Stephen
The unconfined High Plains (Ogallala) aquifer is the largest aquifer in the USA and the primary water supply for the semiarid southern High Plains of Texas and New Mexico. Analyses of water and soils northeast of Amarillo, Texas, together with data from other regional studies, indicate that processes during recharge control the composition of unconfined groundwater in the northern half of the southern High Plains. Solute and isotopic data are consistent with a sequence of episodic precipitation, concentration of solutes in upland soils by evapotranspiration, runoff, and infiltration beneath playas and ditches (modified locally by return flow of wastewater and irrigation tailwater). Plausible reactions during recharge include oxidation of organic matter, dissolution and exsolution of CO2, dissolution of CaCO3, silicate weathering, and cation exchange. Si and 14C data suggest leakage from perched aquifers to the High Plains aquifer. Plausible mass-balance models for the High Plains aquifer include scenarios of flow with leakage but not reactions, flow with reactions but not leakage, and flow with neither reactions nor leakage. Mechanisms of recharge and chemical evolution delineated in this study agree with those noted for other aquifers in the south-central and southwestern USA. Résumé. L'aquifère libre des Hautes Plaines (Ogallala) est le plus vaste aquifère des états-Unis et la ressource de base pour l'eau potable de la région semi-aride du sud des Hautes Plaines du Texas et du Nouveau-Mexique. Des analyses de l'eau et des sols prélevés au nord-est d'Amarillo (Texas), associées à des données provenant d'autres études dans cette région, indiquent que des processus intervenant au cours de l'infiltration contrôlent la composition de l'eau de la nappe libre dans la moitié septentrionale du sud des Hautes Plaines. Les données chimiques et isotopiques sont compatibles avec une séquence de précipitation épisodique, avec la reconcentration en solut
Herrmann, Frank; Baghdadi, Nicolas; Blaschek, Michael; Deidda, Roberto; Duttmann, Rainer; La Jeunesse, Isabelle; Sellami, Haykel; Vereecken, Harry; Wendland, Frank
We used observed climate data, an ensemble of four GCM-RCM combinations (global and regional climate models) and the water balance model mGROWA to estimate present and future groundwater recharge for the intensively-used Thau lagoon catchment in southern France. In addition to a highly resolved soil map, soil moisture distributions obtained from SAR-images (Synthetic Aperture Radar) were used to derive the spatial distribution of soil parameters covering the full simulation domain. Doing so helped us to assess the impact of different soil parameter sources on the modelled groundwater recharge levels. Groundwater recharge was simulated in monthly time steps using the ensemble approach and analysed in its spatial and temporal variability. The soil parameters originating from both sources led to very similar groundwater recharge rates, proving that soil parameters derived from SAR images may replace traditionally used soil maps in regions where soil maps are sparse or missing. Additionally, we showed that the variance in different GCM-RCMs influences the projected magnitude of future groundwater recharge change significantly more than the variance in the soil parameter distributions derived from the two different sources. For the period between 1950 and 2100, climate change impacts based on the climate model ensemble indicated that overall groundwater recharge will possibly show a low to moderate decrease in the Thau catchment. However, as no clear trend resulted from the ensemble simulations, reliable recommendations for adapting the regional groundwater management to changed available groundwater volumes could not be derived. Copyright © 2015 Elsevier B.V. All rights reserved.
M. O. Cuthbert
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.
Cuthbert, M.O.; Mackay, R.; Nimmo, J.R.
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.
Mermillod-Blondin, Florian; Simon, Laurent; Maazouzi, Chafik; Foulquier, Arnaud; Delolme, Cécile; Marmonier, Pierre
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
W. A. Timms
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
Maddock, Thomas, III.; Vionnet, Leticia Beatriz
"Capture" is the increase in recharge and the decrease in discharge that occurs when pumping is imposed on an aquifer system that was in a previous state of approximate dynamic equilibrium. Regional groundwater models are usually used to calculate capture in a two-step procedure. A steady-state solution provides an initial-head configuration, a set of flows through the boundaries for the modeled region, and the initial basis for the capture calculation. The transient solutions provide the total change in flows through the boundaries. A difference between the transient and steady-state solutions renders the capture calculation. When seasonality is a modeling issue, the use of a single initial hydraulic head and a single set of boundary flows leads to miscalculations of capture. Instead, an initial condition for each season should be used. This approach may be accomplished by determining steady oscillatory solutions, which vary through the seasons but repeat from year to year. A regional groundwater model previously developed for a portion of the San Pedro River basin, Arizona, USA, is modified to illustrate the effect that different initial conditions have on transient solutions and on capture calculations. Résumé Les "prélèvements" sont constitués par l'augmentation de la recharge et par la diminution de l'écoulement qui se produit lorsqu'un pompage est imposéà un système aquifère qui était auparavant dans un état proche de l'équilibre dynamique. Les modèles régionaux de nappe sont en général utilisés pour calculer les prélèvements dans une procédure à deux étapes. Une solution en régime permanent donne la configuration piézométrique initiale, un jeu de conditions aux limites pour la région modélisée et les données de base pour le calcul des prélèvements. Les solutions transitoires donnent les modifications globales des conditions aux limites. Lorsque des variations saisonnières sont produites en sortie du modèle, le recours à une
Beyer, Matthias; Gaj, Marcel; Hamutoko, Josefina Tulimeveva; Koeniger, Paul; Wanke, Heike; Himmelsbach, Thomas
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
Wang, Shiqin; Tang, Changyuan; Song, Xianfang; Wang, Qinxue; Zhang, Yinghua; Yuan, Ruiqiang
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. Copyright © 2014 Elsevier B.V. All rights reserved.
D'Agnese, F. A.; Faunt, C.C.; Turner, A.K.; ,
The recharge and discharge components of the Death Valley regional groundwater flow system were defined by techniques that integrated disparate data types to develop a spatially complex representation of near-surface hydrological processes. Image classification methods were applied to multispectral satellite data to produce a vegetation map. The vegetation map was combined with ancillary data in a GIS to delineate different types of wetlands, phreatophytes and wet playa areas. Existing evapotranspiration-rate estimates were used to calculate discharge volumes for these area. An empirical method of groundwater recharge estimation was modified to incorporate data describing soil-moisture conditions, and a recharge potential map was produced. These discharge and recharge maps were readily converted to data arrays for numerical modelling codes. Inverse parameter estimation techniques also used these data to evaluate the reliability and sensitivity of estimated values.The recharge and discharge components of the Death Valley regional groundwater flow system were defined by remote sensing and GIS techniques that integrated disparate data types to develop a spatially complex representation of near-surface hydrological processes. Image classification methods were applied to multispectral satellite data to produce a vegetation map. This map provided a basis for subsequent evapotranspiration and infiltration estimations. The vegetation map was combined with ancillary data in a GIS to delineate different types of wetlands, phreatophytes and wet playa areas. Existing evapotranspiration-rate estimates were then used to calculate discharge volumes for these areas. A previously used empirical method of groundwater recharge estimation was modified by GIS methods to incorporate data describing soil-moisture conditions, and a recharge potential map was produced. These discharge and recharge maps were readily converted to data arrays for numerical modelling codes. Inverse parameter
Wang, Shiqin [Faculty of Horticulture, Chiba University, Matsudo-City 271-8510 (Japan); Tang, Changyuan, E-mail: firstname.lastname@example.org [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)
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
Constantz, Jim; Thomas, Carole L.; Zellweger, Gary W.
, indicating that 95% of the loss within the study reach represented groundwater recharge.
Dripps, W.R.; Bradbury, K.R.
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.
Rotiroti, Marco; Bonomi, Tullia; Fumagalli, Letizia; Taviani, Sara; Stefania, Gennaro A.; Zanotti, Chiara; Patelli, Martina; Soler, Valentina; Sacchi, Elisa; Leoni, Barbara
The investigation of groundwater recharge and discharge areas is crucial to define groundwater flowpaths and assess groundwater vulnerability to pollution. To this purpose, stable isotopes of the water molecule and hydrochemistry were used to investigate an area located in the Po Plain (N Italy) that is highly impacted by human activities, in particular, by agriculture. The study area covers ˜1900 km2 of the Oglio River basin, between the outflow from Lake Iseo and the confluence into Mella River. This area hosts a sandy mono-layer aquifer in its northern part (higher plain), that passes southwards into a multi-layer aquifer (lower plain) with increasing silt and clay contents. The transition between higher and lower plain is marked by a series of springs, the so called "spring belt". The area is crossed by hundreds of irrigation channels, fed by Oglio River water in its upstream stretch. During 4 field surveys (November 2015, February, June and September 2016), groundwater, Oglio River and its main tributaries, Lake Iseo and springs were sampled. In each survey, up to 58 groundwater, 20 river water, 1 lake water and 7 spring water samples were collected. Rainwater was continuously collected between November 2015 and 2016 at 2 locations. All water samples were analysed for major ions, trace elements (Mn, Fe and As) and δ18O/δ2H in water. Hydrochemical data showed that the higher plain is characterized by an oxidized hydrofacies with higher concentrations of NO3 whereas the lower plain shows a reduced hydrofacies with higher concentrations of Mn, Fe, As and NH4. This is mostly related to the aquifer permeability and suggests conditions open to surface recharge in the former. Indeed, water isotopes revealed that the aquifer in the higher plain is recharged by surface water (irrigation channels and Oglio River in its upstream stretch) and local precipitation, and discharges into springs, the Oglio River and through well abstractions; Lake Iseo does not directly
Groundwater and surface water interactions within riparian corridors impact the distribution of phreatophytes that tap into groundwater stores. The changes in canopy area of phreatophytes over time is related to changes in depth to groundwater, distance from a stream or river, and hydrologic soil gr...
Clark, J. F.; Becker, T.; Johnson, T. A.
Recycling wastewater for potable and nonpotable use by artificially recharging aquifers is a decades-old but increasingly popular practice. Natural attenuation processes in the subsurface, known as soil aquifer treatment (SAT), purify recycled water during recharge and subsequent groundwater flow. Travel time criteria are often used to regulate managed aquifer recharge (MAR) operations. California state draft regulations currently gives preference to groundwater tracers to quantify underground residence time, with a target retention time of >6 months from infiltration to drinking water extraction for surface spreading projects using tertiary treated wastewater (less time may be possible if full advanced treated water is utilized). In the past sulfur hexafluoride, a very strong greenhouse gas, has been the principle deliberate tracer for this work. However, its emission has recently become regulated in California and new tracers are needed. Here, two prospective tracers are evaluated: boron-10 (B-10), the least abundant boron isotope, and heat (with recharging water naturally warmed at the sewage treatment plants and in surface-spreading basins). An additional deliberate tracer, bromide (Br), which is a well-studied conservative tracer, was released as a control. Tracer injection occurred at the San Gabriel Spreading Grounds research test basin in Los Angeles County, CA, USA. The basin was constructed and characterized by the US Geological Survey in the mid-1990s. Recycled wastewater was piped directly to this basin at a known rate (about 1.5 m3/day). Down gradient from the test basin are nine high quality monitoring wells in a line that extends from the center of the basin to 150 m down gradient. All of the wells were equipped with temperature loggers that recorded groundwater temperatures every hour with an accuracy of one thousandth of a degree. The pre-experiment expected arrival times ranged from less than one day to six months. Arrival of Br was always
Bachand, Philip A M; Roy, Sujoy B; Choperena, Joe; Cameron, Don; Horwath, William R
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.
Characterization of Recharge Mechanisms and Sources of Groundwater Salinization in Ras Jbel Coastal Aquifer (Northeast Tunisia Using Hydrogeochemical Tools, Environmental Isotopes, GIS, and Statistics
Jamila Hammami Abidi
Full Text Available Groundwater is among the most available water resources in Tunisia; it is a vital natural resource in arid and semiarid regions. Located in north-eastern Tunisia, the Metline-Ras Jbel-Raf Raf aquifer is a mio-plio-quaternary shallow coastal aquifer, where groundwater is the most important source of water supply. The major ion hydrochemistry and environmental isotope composition (δ18O, δ2H were investigated to identify the recharge sources and processes that affect the groundwater salinization. The combination of hydrogeochemical, isotopic, statistical, and GIS approaches demonstrates that the salinity and the groundwater composition are largely controlled by the water-rock interaction particularly the dissolution of evaporate minerals and the ion exchange process, the return flow of the irrigation water, agricultural fertilizers, and finally saltwater intrusion which started before 1980 and which is partially mitigated by the artificial recharge since 1993. As for the stable isotope signatures, results showed that groundwater samples lay on and around the local meteoric water line LMWL; hence, this arrangement signifies that the recharge of the Ras Jbel aquifer is ensured by recent recharge from Mediterranean air masses.
Sakakibara, Koichi; Tsujimura, Maki; Song, Xianfang; Zhang, Jie
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
Pino, Cristian; Herrera, Paulo; Therrien, René
In many arid regions around the world groundwater recharge occurs during flash floods. This transient spatially and temporally concentrated flood-recharge process takes place through the variably saturated zone between surface and usually the deep groundwater table. These flood events are characterized by rapid and extreme changes in surface flow depth and velocity and soil moisture conditions. Infiltration rates change over time controlled by the hydraulic gradients and the unsaturated hydraulic conductivity at the surface-subsurface interface. Today is a challenge to assess the spatial and temporal distribution of groundwater recharge from flash flood events under real field conditions at different scales in arid areas. We apply an integrated surface-subsurface variably saturated physically-based flow model at the watershed scale to assess the recharge process during and after a flash flood event registered in an arid fluvial valley in Northern Chile. We are able to reproduce reasonably well observed groundwater levels and surface flow discharges during and after the flood with a calibrated model. We also investigate the magnitude and spatio-temporal distribution of recharge and the response of the system to variations of different surface and subsurface parameters, initial soil moisture content and groundwater table depths and surface flow conditions. We demonstrate how an integrated physically based model allows the exploration of different spatial and temporal system states, and that the analysis of the results of the simulations help us to improve our understanding of the recharge processes in similar type of systems that are common to many arid areas around the world.
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.
Lin, Y.; Bajcsy, P.; Valocchi, A. J.; Kim, C.; Wang, J.
Natural systems are complex, thus extensive data are needed for their characterization. However, data acquisition is expensive; consequently we develop models using sparse, uncertain information. When all uncertainties in the system are considered, the number of alternative conceptual models is large. Traditionally, the development of a conceptual model has relied on subjective professional judgment. Good judgment is based on experience in coordinating and understanding auxiliary information which is correlated to the model but difficult to be quantified into the mathematical model. For example, groundwater recharge and discharge (R&D) processes are known to relate to multiple information sources such as soil type, river and lake location, irrigation patterns and land use. Although hydrologists have been trying to understand and model the interaction between each of these information sources and R&D processes, it is extremely difficult to quantify their correlations using a universal approach due to the complexity of the processes, the spatiotemporal distribution and uncertainty. There is currently no single method capable of estimating R&D rates and patterns for all practical applications. Chamberlin (1890) recommended use of "multiple working hypotheses" (alternative conceptual models) for rapid advancement in understanding of applied and theoretical problems. Therefore, cross analyzing R&D rates and patterns from various estimation methods and related field information will likely be superior to using only a single estimation method. We have developed the Pattern Recognition Utility (PRU), to help GIS users recognize spatial patterns from noisy 2D image. This GIS plug-in utility has been applied to help hydrogeologists establish alternative R&D conceptual models in a more efficient way than conventional methods. The PRU uses numerical methods and image processing algorithms to estimate and visualize shallow R&D patterns and rates. It can provide a fast initial
Jacquemin, Ingrid; Verbeiren, Boud; Vanderhaegen, Sven; Canters, Frank; Vermeiren, Karolien; Engelen, Guy; Huysmans, Marijke; Batelaan, Okke; Tychon, Bernard
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
Dong, Shaogang; Liu, Baiwei; Liu, Huamin; Wang, Shidong; Wang, Lixin
In the rubber dam's impact area, the groundwater total hardness (TH) has declined since 2000, ultimately dropping to 100–300 mg/L in 2012. pH levels have shown no obvious changes. NH4-N concentration in the groundwater remained stable from 2000 to 2006, but it increased from 2007 to 2012, with the largest increase up to 0.2 mg/L. NO3-N concentration in the groundwater generally declined in 2000–2006 and then increased from 2007; the largest increase was to 10 mg/L in 2012. Total dissolved solids (TDS) of the groundwater showed a general trend of decline from 2000 to 2009, but levels increased after 2010, especially along the south bank of the Luohe River where the largest increase recorded was approximately 100 mg/L. This study has shown that the increases in the concentrations of NH4-N and NO3-N were probably caused by changes in groundwater levels. Nitrates adsorbed by the silt clay of aeration zone appear to have entered the groundwater through physical and chemical reactions. TDS increased because of groundwater evaporation and some soluble ions entered the groundwater in the unsaturated zone. The distance of the contaminant to the surface of the aquifer became shorter due to the shallow depth of groundwater, resulting in the observed rise in pollutant concentrations more pronounced. PMID:25126593
Dong, Shaogang; Liu, Baiwei; Liu, Huamin; Wang, Shidong; Wang, Lixin
In the rubber dam's impact area, the groundwater total hardness (TH) has declined since 2000, ultimately dropping to 100-300 mg/L in 2012. pH levels have shown no obvious changes. NH4-N concentration in the groundwater remained stable from 2000 to 2006, but it increased from 2007 to 2012, with the largest increase up to 0.2 mg/L. NO3-N concentration in the groundwater generally declined in 2000-2006 and then increased from 2007; the largest increase was to 10 mg/L in 2012. Total dissolved solids (TDS) of the groundwater showed a general trend of decline from 2000 to 2009, but levels increased after 2010, especially along the south bank of the Luohe River where the largest increase recorded was approximately 100 mg/L. This study has shown that the increases in the concentrations of NH4-N and NO3-N were probably caused by changes in groundwater levels. Nitrates adsorbed by the silt clay of aeration zone appear to have entered the groundwater through physical and chemical reactions. TDS increased because of groundwater evaporation and some soluble ions entered the groundwater in the unsaturated zone. The distance of the contaminant to the surface of the aquifer became shorter due to the shallow depth of groundwater, resulting in the observed rise in pollutant concentrations more pronounced.
Gowrisankar, G; Jagadeshan, G; Elango, L
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.
Alslaibi, Tamer M; Kishawi, Yasser; Abunada, Ziyad
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 NO3(-) 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.
Saha, Dipankar; Dwivedi, S. N.; Roy, Goutam Kr; Reddy, D. V.
Ranchi urban area (257 km2) depends on aquifers for 30 % of its total drinking-water supply of 17 million m3 year-1. Local hydrostratigraphy is represented by a heterogeneous, weathered and fractured aquifer system, typical of the Precambrian suite of rocks in the Indian subcontinent. Intensive development of the fractured aquifers, up to 200 m below ground, has lowered the hydraulic head and resulted in dwindling yields from fractures during the summer. To understand the groundwater flow regime and aquifer recharge mechanism, the present study examines δ18O and δD variation in aquifer-specific samples along with water levels, yield of the fractures, EC and Cl-. Three types of groundwater have been identified based on isotopic composition and d-excess values, each representing different recharge source-water and pathways. The major source of recharge for the aquifers is infiltration from rainfall. Two large reservoirs and an excavated lake within the study area contribute to the recharge process but insignificantly. Isotopic compositions and the relatively low EC and low Cl- concentrations of high-yielding bore wells in some places indicate the presence of fast-conducting fracture zones receiving copious recharge from rainfall. Such fractures can be developed further through bore wells for drinking supply with due provision for artificial recharge.
trench system as an interim remedial action. The NBT was previ- ously deficient in its recharge functions, especially west of D Street, because of the...Phillips Supac 4 NP,* a 4-oz/yd 2 nonwoven polyester. Two observational piezometers were placed in each trench (Figure 2) and ten others were located
Sibanda, T.; Nonner, J.C.; Uhlenbrook, S.
The Nyamandhlovu aquifer is the main water resource in the semi-arid Umguza district in Matebeleland North Province in Zimbabwe. The rapid increase in water demand in the city of Bulawayo has prompted the need to quantify the available groundwater resources for sustainable utilization. Groundwater
Welch, L.A.; Allen, D.M.; van Meerveld, H.J.
An important, yet poorly understood, influence on the hydrologic behaviour of mountain headwater streams is deep groundwater (DG) flow, which circulates at depth through the bedrock system and discharges to surface water or shallow groundwater at stream valleys. In this study, two- and
Nizar Shamsuddin Mohd Khairul
Full Text Available Groundwater tables forecasting during implemented river bank infiltration (RBI method is important to identify adequate storage of groundwater aquifer for water supply purposes. This study illustrates the development and application of artificial neural networks (ANNs to predict groundwater tables in two vertical wells located in confined aquifer adjacent to the Langat River. ANN model was used in this study is based on the long period forecasting of daily groundwater tables. ANN models were carried out to predict groundwater tables for 1 day ahead at two different geological materials. The input to the ANN models consider of daily rainfall, river stage, water level, stream flow rate, temperature and groundwater level. Two different type of ANNs structure were used to predict the fluctuation of groundwater tables and compared the best forecasting values. The performance of different models structure of the ANN is used to identify the fluctuation of the groundwater table and provide acceptable predictions. Dynamics prediction and time series of the system can be implemented in two possible ways of modelling. The coefficient correlation (R, Mean Square Error (MSE, Root Mean Square Error (RMSE and coefficient determination (R2 were chosen as the selection criteria of the best model. The statistical values for DW1 are 0.8649, 0.0356, 0.01, and 0.748 respectively. While for DW2 the statistical values are 0.7392, 0.0781, 0.0139, and 0.546 respectively. Based on these results, it clearly shows that accurate predictions can be achieved with time series 1-day ahead of forecasting groundwater table and the interaction between river and aquifer can be examine. The findings of the study can be used to assist policy marker to manage groundwater resources by using RBI method.
Dietsch, Benjamin J.; Wehmeyer, Loren L.
The U.S. Geological Survey—in cooperation with the U.S. Army Corps of Engineers, Fort Worth District; City of Corpus Christi; Guadalupe–Blanco River Authority; San Antonio River Authority; and San Antonio Water System— configured, calibrated, and tested a watershed model for a study area consisting of about 7,726 square miles of the middle Nueces River watershed in south Texas. The purpose of the model is to contribute to the understanding of watershed processes and hydrologic conditions in the middle Nueces River watershed. The model simulates streamflow, evapotranspiration, and groundwater recharge by using a numerical representation of physical characteristics of the landscape and meteorological and streamflow data.
Fournier, Eric D; Keller, Arturo A; Geyer, Roland; Frew, James
This project investigates the energy-water usage efficiency of large scale civil infrastructure projects involving the artificial recharge of subsurface groundwater aquifers via the reuse of treated municipal wastewater. A modeling framework is introduced which explores the various ways in which spatially heterogeneous variables such as topography, landuse, and subsurface infiltration capacity combine to determine the physical layout of proposed reuse system components and their associated process energy-water demands. This framework is applied to the planning and evaluation of the energy-water usage efficiency of hypothetical reuse systems in five case study regions within the State of California. Findings from these case study analyses suggest that, in certain geographic contexts, the water requirements attributable to the process energy consumption of a reuse system can exceed the volume of water that it is able to recover by as much as an order of magnitude.
Meredith, Karina; Cendón, Dioni I; Pigois, Jon-Philippe; Hollins, Suzanne; Jacobsen, Geraldine
The Gnangara Mound and the underlying Perth Basin aquifers are the largest source of groundwater for the southwest of Australia, supplying between 35 and 50% of Perth's potable water (2009-2010). However, declining health of wetlands on the Mound coupled with the reduction in groundwater levels from increased irrigation demands and drier climatic conditions means this resource is experiencing increased pressures. The northern Gnangara is an area where the Yarragadee aquifer occurs at shallow depths (~50 m) and is in direct contact with the superficial aquifer, suggesting the possibility of direct recharge into a generally confined aquifer. Environmental isotopes ((14)C and (3)H) and hydrochemical modelling were used to assess the presence of a recharge 'window' as well as understand the groundwater residence time within different aquifers. Forty-nine groundwater samples were collected from depths ranging from 11 to 311 m below ground surface. The isotopic variation observed in the superficial aquifer was found to be controlled by the different lithologies present, i.e. quartz-rich Bassendean Sand and carbonate-rich sediments of the Ascot Formation. Rainfall recharge into the Bassendean Sand inherits its dissolved inorganic carbon from the soil CO(2). Organic matter throughout the soil profile is degraded by oxidation leading to anoxic/acidic groundwater, which if in contact with the Ascot Formation leads to enhanced dissolution of carbonates. Hydrochemical mass balance modelling showed that carbonate dissolution could contribute 1-2 mmol kg(-1) of carbon to groundwaters recharged through the Ascot Formation. The corrected groundwater residence times of the Yarragadee aquifer in the northern part of the study area ranged from 23 to 35 ka, while waters in the southeastern corner ranged from sub-modern to 2 ka. Groundwater ages increase with distance radiating from the recharge 'window'. This study delineates a recharge 'window' into the commonly presumed confined
Bradshaw, Jonathan L; Luthy, Richard G
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.
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
Barlow, Paul M.; Cunningham, William L.; Zhai, Tong; Gray, Mark
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.
GUPTA, GAUTAM; PATIL, S N; PADMANE, S T; ERRAM, VINIT C; MAHAJAN, S H
.... Groundwater is the major source of irrigation and domestic purposes. To assess the overall water resources development of Raver area for better environment in future, investigation was carried out with the help of geophysical indicators...
Humphries, Marc S.; Kindness, Andrew; Ellery, William N.; Hughes, Jeffrey C.; Bond, Jonathan K.; Barnes, Kirsten B.
SummaryKnowledge of wetland systems from sub-humid and semi-arid regions remains poor, particularly with regards to surface water-groundwater interactions. As a result of variable inflow and high evapotranspiration rates, such systems are often associated with the development of groundwater salinity. By focusing on the riparian species, Acacia xanthophloea, this study investigates the interaction between vegetation, groundwater, and occurrence of salinity on the Mkuze River floodplain, a seasonally dry, freshwater wetland. The relationship between groundwater chemistry and water table elevation suggests that these deep-rooted trees act as evapotranspirational pumps, selectively removing water and causing the subsurface concentration of solutes. Extensive root systems that reach the water table, coupled with high transpiration rates, result in local groundwater reaching electrical conductivities in excess of 20 mS/cm, approximately 15-20 times higher than those commonly found elsewhere on the floodplain. In this environment, these trees appear tolerant of salinities that would be toxic to most other plants. Plant tissue ion concentrations indicate that solute exclusion is the dominant means for avoidance of salt toxicity, with root turnover a possible regulatory mechanism. Data presented support our hypothesis that these trees exert feedback interactions on groundwater and sediment chemistry. Transpiration results not only in the development of saline groundwater, which is likely to influence vegetation distribution, but also initiates the precipitation of less soluble minerals, such as CaCO 3 and SiO 2, which have the potential to modify sediment pH, hydraulic conductivity, and landscape topography. Spatial variation in chemical processing is thus likely to play a role in creating and maintaining habitat diversity on the floodplain. Wetlands in semi-arid and sub-humid regions are often susceptible to shallow groundwater chemical transformations due to seasonal or
Karstic groundwater basins are characterized by both point and diffuse recharge. This paper describes the hydrologic characteristics of point recharge and their influence on recharge estimation for four groundwater basins. Point recharge is highly transient and may occur in relatively short-time periods, yet is capable of recharging a large volume of water, even from a single extreme rainfall event. Preferential groundwater flows are observed in karst aquifers with local fresher water pockets...
Garel, Emilie; Huneau, Frederic; Khoumeri, Beatrice; Travi, Yves
Bonifacio is a coastal city, highly touristic, located in the southest part of Corsica Island. One million people visit the city in July and August, whereas 3000 inhabitants live throughout the year. Bonifacio lies on a small limestone plateau with a potential aquifer poorly understood. Actually there is a strong need to characterize the hydrogeological behavior for the reason that the economic development of the region is highly dependent of the groundwater supply potential. The Miocene sedimentary basin of Bonifacio has an area of 25 km2 with a depth up to 250 m in the center. It is based and surrounded by a Hercynian granitic substratum. The basin is open to the Mediterranean Sea on its south and east sides. The formation is calcareous-sandstone and is divided in 3 sedimentary units. The upper unit is highly calcareous and sandstone with a pseudo-karstic morphology, the intermediary unit is more silty-sandstone than the last but less than the unit from below. To establish a conceptual model of the groundwater flows of the Bonifacio aquifer, a hydrochemical (major ions, δ18O, δ2H, 3H) and hydrodynamic investigation was carried out on 12 wells, 1 spring and 1 river since May 2011. Vertical recharge is dominant in the centre of the aquifer where unsaturated zone is thicker, while on the aquifer boundaries with the granitic area, lateral flow was significant. Environmental tracers approach had clearly showed the important role of the boundaries conditions for the groundwater flow behavior of the aquifer of Bonifacio and the necessity of an investigation larger than the aquifer itself due to its limited spatial extension.
Giovanni Pietro Beretta
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.
Stamos, Christina L.; Martin, Peter; Everett, Rhett; Izbicki, John A.
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
Gumuła-Kawęcka, Anna; Szymkiewicz, Adam; Angulo-Jaramillo, Rafael; Šimůnek, Jirka; Jaworska-Szulc, Beata; Pruszkowska-Caceres, Małgorzata; Gorczewska-Langner, Wioletta; Leterme, Bertrand; Jacques, Diederik
ABSTRACT Groundwater recharge is a complex process, which depends on several factors, including the hydraulic properties of soils in the vadose zone. On the other hand, the rate of recharge is one of the main input data in hydrogeological models for saturated groundwater flow. Thus, there is an increasing understanding of the need for more complete representation of vadose zone processes in groundwater modeling. One of the possible approaches is to use a 1D model of water flow in the unsaturated zone coupled with 3D groundwater model for the saturated zone. Such an approach was implemented in the Hydrus for Modflow package (Seo et al. 2007), which combines two well-known and thoroughly tested modeling tools: groundwater flow simulator MODFLOW (Harbaugh 2005) and one-dimensional vadose zone simulator HYDRUS 1D (Šimůnek et al. 2016), based on the Richards equation. The Hydrus for Modflow package has been recently enhanced by implementing the BEST model of soil hydraulic properties (Lassabatere et al. 2006), which is a combination of van Genuchten - type retention function with Brooks-Corey type hydraulic conductivity function. The parameters of these functions can be divided into texture-related and structure-related and can be obtained from relatively simple lab and field tests. The method appears a promising tool for obtaining input data for vadose zone flow models. The main objective of this work is to evaluate the sensitivity of the recharge rates to the values of various parameters of the BEST model. Simulations are performed for a range of soil textural classes and plant covers, using meteorological data typical for northern Poland. ACKNOWLEDGEMENTS This work has been supported by National Science Centre, Poland in the framework of the project 2015/17/B/ST10/03233 "Groundwater recharge on outwash plain". REFERENCES Harbaugh, A.W. (2005) MODFLOW-2005, the US Geological Survey modular ground-water model: the ground-water flow process. Reston, VA, USA. [2
Kelly, Brian P.; Pickett, Linda L.; Hansen, Cristi V.; Ziegler, Andrew C.
Arkansas River for the transient simulation is 7,916,564 cubic feet per day (91.6 cubic feet per second) and the RMS error divided by (/) the total range in streamflow (7,916,564/37,461,669 cubic feet per day) is 22 percent. The RMS error calculated for observed and simulated streamflow gains or losses for the Little Arkansas River for the transient simulation is 5,610,089 cubic feet per day(64.9 cubic feet per second) and the RMS error divided by the total range in streamflow (5,612,918/41,791,091 cubic feet per day) is 13 percent. The mean error between observed and simulated base flow gains or losses was 29,999 cubic feet per day (0.34 cubic feet per second) for the Arkansas River and -1,369,250 cubic feet per day (-15.8 cubic feet per second) for the Little Arkansas River. Cumulative streamflow gain and loss observations are similar to the cumulative simulated equivalents. Average percent mass balance difference for individual stress periods ranged from -0.46 to 0.51 percent. The cumulative mass balance for the transient calibration was 0.01 percent. Composite scaled sensitivities indicate the simulations are most sensitive to parameters with a large areal distribution. For the steady-state calibration, these parameters include recharge, hydraulic conductivity, and vertical conductance. For the transient simulation, these parameters include evapotranspiration, recharge, and hydraulic conductivity. The ability of the calibrated model to account for the additional groundwater recharged to the Equus Beds aquifer as part of the Aquifer Storage and Recovery project was assessed by using the U.S. Geological Survey subregional water budget program ZONEBUDGET and comparing those results to metered recharge for 2007 and 2008 and previous estimates of artificial recharge. The change in storage between simulations is the volume of water that estimates the recharge credit for the aquifer storage and recovery system. The estimated increase in storage of 1,607 acre-ft in the basin
Hoppe-Jones, Christiane; Dickenson, Eric R V; Drewes, Jörg E
It is widely recognized that efficient biological attenuation of bulk organic matter and trace organic chemicals (TOrC) can occur in managed aquifer recharge (MAR) systems receiving reclaimed water. The heterotrophic microbial activity in these subsurface systems is a function of the availability of biodegradable dissolved organic carbon (BDOC) present in reclaimed water. This study examined the influence of environmental factors, such as BDOC-rich (>1.6 mg/L) and BDOC-starving (groundwater recharge. Under conditions that were characterized by a lack of BDOC and a biocommunity that was not yet adapted to these conditions, attenuation of biodegradable TOrC was less than 15%. After a three-month adaptation period, biotransformation increased to more than 80% for the biodegradable TOrC. This suggests that adaptation likely initiates enzyme expressions that eventually results in TOrC transformations even under seemingly less favorable conditions (i.e., lack of biodegradable carbon). For both non-adapted (stressed) and adapted conditions in the presence of higher concentrations of BDOC and travel times of 7 days, the degree of biotransformation was variable across compounds but generally exceeded 25%. This suggests that BDOC above a minimum level (>1.6 mg/L) can provide favorable microbial conditions resulting in TOrC removal, even for non-adapted systems. However, it is noteworthy that adapted MAR systems that were fed with low BDOC levels performed similarly or better with respect to TOrC biotransformation than systems that received BDOC levels above 1.6 mg/L. These findings are important for field-scale applications. They suggest that MAR facilities that are microbiologically active and are fed with highly treated water with effluent concentrations of less than 1 mg/L (i.e., nanofiltration permeate) can still attenuate biodegradable TOrC. Copyright © 2012 Elsevier B.V. All rights reserved.
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.
Oden, Timothy D.; Truini, Margot
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
Wieczorek, Michael; LaMotte, Andrew E.
This data set represents the mean annual natural groundwater recharge, in millimeters, compiled for every catchment of NHDPlus for the conterminous United States. The source data set is Estimated Mean Annual Natural Ground-Water Recharge in the Conterminous United States (Wolock, 2003). The NHDPlus Version 1.1 is an integrated suite of application-ready geospatial datasets that incorporates many of the best features of the National Hydrography Dataset (NHD) and the National Elevation Dataset (NED). The NHDPlus includes a stream network (based on the 1:100,00-scale NHD), improved networking, naming, and value-added attributes (VAAs). NHDPlus also includes elevation-derived catchments (drainage areas) produced using a drainage enforcement technique first widely used in New England, and thus referred to as "the New England Method." This technique involves "burning in" the 1:100,000-scale NHD and when available building "walls" using the National Watershed Boundary Dataset (WBD). The resulting modified digital elevation model (HydroDEM) is used to produce hydrologic derivatives that agree with the NHD and WBD. Over the past two years, an interdisciplinary team from the U.S. Geological Survey (USGS), and the U.S. Environmental Protection Agency (USEPA), and contractors, found that this method produces the best quality NHD catchments using an automated process (USEPA, 2007). The NHDPlus dataset is organized by 18 Production Units that cover the conterminous United States. The NHDPlus version 1.1 data are grouped by the U.S. Geologic Survey's Major River Basins (MRBs, Crawford and others, 2006). MRB1, covering the New England and Mid-Atlantic River basins, containing NHDPlus Production Units 1 and 2. MRB2, covering the South Atlantic-Gulf and Tennessee River basins, contains NHDPlus Production Units 3 and 6. MRB3, covering the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy River basins, contains NHDPlus Production Units 4, 5, 7 and 9. MRB4, covering the
Richards, Laura A.; Magnone, Daniel; Boyce, Adrian J.; Casanueva-Marenco, Maria J.; van Dongen, Bart E.; Ballentine, Christopher J.; Polya, David A.
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.
Flint, Lorraine E.; Contributions by Brandt, Justin; Christensen, Allen H.; Flint, Alan L.; Hevesi, Joseph A.; Jachens, Robert; Kulongoski, Justin T.; Martin, Peter; Sneed, Michelle
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
Full Text Available Indonesian is huge areas that have the highest precipitation in the world, therefore water deficit of groundwater is often happened at anywhere. This study was related to determination of recharge area with approached by combining geological setting, stable isotopes and chemical content of groundwater. Case study was carried out at surrounding the Cicurug area, Sukabumi Prefecture, West Java Province. The area is the slopes of Salak Mountain that have elevation of 400 until 1,200 m mean sea level (msl. While, much groundwater supplies industry activities on elevation 450-500 m msl. Based on data and result analysis of the studies, the recharge areas was not around peak of mountain or near, but water infiltrated on elevation of 700-800 m msl for groundwater exploited by industries. Therefore, the accurate determination of recharge area becomes a key for the groundwater sustainability.
Hübner, U; Miehe, U; Jekel, M
Pilot scale experiments using an 8 g/h ozonation unit and a 1.4 m(2) slow sand filter have demonstrated that the combination of ozonation and artificial groundwater recharge is suitable for efficient reduction of bulk and trace organics. The biodegradation of dissolved organic carbon (DOC) in the slow sand filter was enhanced from 22% without pre-treatment to 34% by pre-ozonation. In addition, realistic surface water concentrations of most investigated trace organic compounds (TrOCs) including carbamazepine, sulfamethoxazole, phenazone and metoprolol were reduced below the limits of quantification. Only a few TrOCs, e.g. primidone and benzotriazole, were not efficiently removed in both treatment steps and could be detected regularly in the filter effluent. For these compounds, enhanced treatment, such as advanced oxidation processes, needs to be considered. Testing for genotoxicity and cytotoxicity did not reveal any systematic adverse effects for human health. The formation of the by-product bromate from bromide was below the limit of the German drinking water directive of 10 μg/L. No removal of bromate was observed in the aerobic slow sand filter. Additional experiments with sand columns showed that operating a preceding bank filtration step to reduce DOC can reduce oxidant demand by approximately 20%. Copyright © 2012 Elsevier Ltd. All rights reserved.
Huggenberger, P.; Butscher, C.; Epting, J.; Auckenthaler, A.
Karst groundwater resources represent valuable water resources, which may be affected by different types of pollution and changes of groundwater recharge by climate change. In many parts of Europe, it has been predicted that record-breaking heat waves, such as the one experienced in 2003 and 2015, will become more frequent. At the same time, even as summers become drier, the incidence of severe precipitation events could increase. What is the influence such changes to the quantitative and qualitative aspects of Karst groundwater systems? A factor to be considered in conjunction with groundwater quality is the vulnerability of the resource, which is defined as the sensitivity of a groundwater system to pollution. Intrinsic vulnerability refers to the sensitivity to pollution when considering only natural, geogenic conditions without the effects of human activities such as contaminant release. Intrinsic vulnerability depends on the recharge conditions, which are dependent on the surface and subsurface structure and on precipitation and evaporation patterns. The latter are highly time dependent. Therefore, our groundwater vulnerability concept also includes dynamic aspects of the system, the variations of spatial and temporal components. We present results of combined monitoring and modelling experiments of several types of Karst systems in the Tabular and the Folded Jura of NW Switzerland. The recharge, conduit flow, diffuse flow(RCD) rainfall-discharge model "RCD-seasonal" was used to simulate the discharge and substance concentration of several spring. This lumped parameter model include: the recharge system (soil and epikarst system), the conduit flow system, and the diffuse flow system. The numerically derived Dynamic Vulnerability Index (DVI) can indicate qualitative changes of spring water with sufficient accuracy to be used for drinking water management. In addition, the results obtained from the test sites indicate a decrease in short-lived contaminants in
This study developed relationships between the attenuation of emerging trace organic chemicals (TOrC) during managed aquifer recharge (MAR) as a function of retention time, system characteristics, and operating conditions using controlled laboratory-scale soil column experiments simulating MAR. The results revealed that MAR performance in terms of TOrC attenuation is primarily determined by key environmental parameters (i.e. redox, primary substrate). Soil columns with suboxic and anoxic conditions performed poorly (i.e. less than 30% attenuation of moderately degradable TOrC) in comparison to oxic conditions (on average between 70-100% attenuation for the same compounds) within a residence time of three days. Given this dependency on redox conditions, it was investigated if key parameter-dependent rate constants are more suitable for contaminant transport modeling to properly capture the dynamic TOrC attenuation under field-scale conditions. Laboratory-derived first-order removal kinetics were determined for 19 TOrC under three different redox conditions and rate constants were applied to MAR field data. Our findings suggest that simplified first-order rate constants will most likely not provide any meaningful results if the target compounds exhibit redox dependent biotransformation behavior or if the intention is to exactly capture the decline in concentration over time and distance at field-scale MAR. However, if the intention is to calculate the percent removal after an extended time period and subsurface travel distance, simplified first-order rate constants seem to be sufficient to provide a first estimate on TOrC attenuation during MAR.
Regnery, J; Wing, A D; Alidina, M; Drewes, J E
This study developed relationships between the attenuation of emerging trace organic chemicals (TOrC) during managed aquifer recharge (MAR) as a function of retention time, system characteristics, and operating conditions using controlled laboratory-scale soil column experiments simulating MAR. The results revealed that MAR performance in terms of TOrC attenuation is primarily determined by key environmental parameters (i.e., redox, primary substrate). Soil columns with suboxic and anoxic conditions performed poorly (i.e., less than 30% attenuation of moderately degradable TOrC) in comparison to oxic conditions (on average between 70-100% attenuation for the same compounds) within a residence time of three days. Given this dependency on redox conditions, it was investigated if key parameter-dependent rate constants are more suitable for contaminant transport modeling to properly capture the dynamic TOrC attenuation under field-scale conditions. Laboratory-derived first-order removal kinetics were determined for 19 TOrC under three different redox conditions and rate constants were applied to MAR field data. Our findings suggest that simplified first-order rate constants will most likely not provide any meaningful results if the target compounds exhibit redox dependent biotransformation behavior or if the intention is to exactly capture the decline in concentration over time and distance at field-scale MAR. However, if the intention is to calculate the percent removal after an extended time period and subsurface travel distance, simplified first-order rate constants seem to be sufficient to provide a first estimate on TOrC attenuation during MAR. Copyright © 2015 Elsevier B.V. All rights reserved.
Ma, Weifang; Sun, Jiaji; Li, Yangyao; Lun, Xiaoxiu; Shan, Dan; Nie, Chao; Liu, Miaomiao
This study investigated 17α-ethynylestradiol (EE2) biodegradation process and primary metabolic pathways associated with community structures of microorganism during groundwater recharge using reclaimed water. The attenuation rate is 1.58 times higher in wetting and drying alternative recharge (WDAR) than in continual recharge (CR). The primary biotransformation pathways of EE2 in WDAR system began with the oxidation of C-17 on ring D to form a ketone group, and D-ring was subsequently hydroxylated and cleaved. In the CR system, the metabolic pathway changed from the oxidation of C-17 on ring D to hydroxylation of C-4 on ring A, and ring A or B subsequently cleaved; this transition was related to DO, and the microbial community structure. Four hundred fifty four pyrosequencing of 16s rRNA genes indicated that the bacterial communities in the upper layer of the WDAR system were more diverse than those found in the bottom layer of the CR system; this result was reversed for archaea. Unweighted UniFrac and taxonomic analyses were conducted to relate the change in bacterial community structure to the metabolic pathway. Microorganism community diversity and structure were related to the concentrations of dissolved oxygen, EE2 and its intermediates in the system. Five known bacterial classes and one known archaeal class, five major bacterial genera and one major archaeal genus might be involved in EE2 degradation. The findings of this study provide an understanding of EE2 biodegradation in groundwater recharge areas under different recharging modes and can facilitate the prediction of the fate of EE2 in underground aquifers. Copyright © 2017. Published by Elsevier B.V.
Kasper, Joshua W.; Denver, Judish M.; McKenna, Thomas E.; Ullman, William J.
A numerical groundwater-flow model was used to characterize the source area and volume of Phillips Branch, a baseflow-dominated stream incising a highly permeable unconfined aquifer on the low relief Delmarva Peninsula, USA. Particle-tracking analyses indicate that the source area (5.51 km2) is ~20% smaller than the topographically defined watershed (6.85 km2), and recharge entering ~37% of the surface watershed does not discharge to Phillips Branch. Groundwater residence time within the source volume ranges from a few days to almost 100 years, with 95% of the volume "flushing" within 50 years. Artificial discharge from groundwater pumping alters the shape of the source area and reduces baseflow due to the interception of stream flow paths, but has limited impacts on the residence time of groundwater discharged as baseflow. In contrast, artificial recharge from land-based wastewater disposal substantially reduces the source area, lowers the range in residence time due to the elimination of older flow paths to the stream, and leads to increased discharge to adjacent surface-water bodies. This research suggests that, in this and similar hydrogeologic settings, the "watershed" approach to water-resource management may be limited, particularly where anthropogenic stresses alter the transport of soluble contaminants through highly permeable unconfined aquifers.
J. R. Raposo
Full Text Available Quantifying groundwater recharge in crystalline rocks presents great difficulties due to the high heterogeneity of the underground medium (mainly, due to heterogeneity in fracture network, which determines hydraulic parameters of the bedrock like hydraulic conductivity or effective porosity. Traditionally these rocks have been considered to have very low permeability, and their groundwater resources have usually been neglected; however, they can be of local importance when the bedrock presents a net of well-developed fractures. The current European Water Framework Directive requires an efficient management of all groundwater resources; this begins with a proper knowledge of the aquifer and accurate recharge estimation. In this study, an assessment of groundwater resources in the Spanish hydrologic district of Galicia-Costa, dominated by granitic and metasedimentary rocks, was carried out. A water-balance modeling approach was used for estimating recharge rates in nine pilot catchments representatives of both geologic materials. These results were cross-validated with an independent technique, i.e. the chloride mass balance (CMB. A relation among groundwater recharge and annual precipitation according to two different logistic curves was found for both granites and metasedimentary rocks, thus allowing the parameterization of recharge by means of only a few hydrogeological parameters. Total groundwater resources in Galicia-Costa were estimated to be 4427 hm3 yr−1. An analysis of spatial and temporal variability of recharge was also carried out.
Lizarraga, Joy S.; Ockerman, Darwin J.
The U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, Fort Worth District; the City of Corpus Christi; the Guadalupe-Blanco River Authority; the San Antonio River Authority; and the San Antonio Water System, configured, calibrated, and tested a watershed model for a study area consisting of about 5,490 mi2 of the Frio River watershed in south Texas. The purpose of the model is to contribute to the understanding of watershed processes and hydrologic conditions in the lower Frio River watershed. The model simulates streamflow, evapotranspiration (ET), and groundwater recharge by using a numerical representation of physical characteristics of the landscape, and meteorological and streamflow data. Additional time-series inputs to the model include wastewater-treatment-plant discharges, surface-water withdrawals, and estimated groundwater inflow from Leona Springs. Model simulations of streamflow, ET, and groundwater recharge were done for various periods of record depending upon available measured data for input and comparison, starting as early as 1961. Because of the large size of the study area, the lower Frio River watershed was divided into 12 subwatersheds; separate Hydrological Simulation Program-FORTRAN models were developed for each subwatershed. Simulation of the overall study area involved running simulations in downstream order. Output from the model was summarized by subwatershed, point locations, reservoir reaches, and the Carrizo-Wilcox aquifer outcrop. Four long-term U.S. Geological Survey streamflow-gaging stations and two short-term streamflow-gaging stations were used for streamflow model calibration and testing with data from 1991-2008. Calibration was based on data from 2000-08, and testing was based on data from 1991-99. Choke Canyon Reservoir stage data from 1992-2008 and monthly evaporation estimates from 1999-2008 also were used for model calibration. Additionally, 2006-08 ET data from a U.S. Geological Survey
Sinner, K.; Teasley, R. L.
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
Coes, A.L.; Spruill, T.B.; Thomasson, M.J.
Recharge rates determined at diverse study sites in a shallow, unconfined aquifer differed from one another depending on the analytical method used and on each method's applicability and limitations. Total recharge was quantified with saturated-zone methods using water-table fluctuations at seven sites in North Carolina, USA and using groundwater-age dating at three of the seven sites; at two of the sites, potential recharge was quantified with an unsaturated-zone method using Darcy's law; and at five of the sites, net recharge was quantified with a stream hydrograph-separation method using streamflow-recession curves. Historical mean net recharge was 25 to 69% of the historical total recharge rates. The large disparity is attributed to groundwater losses between recharge and discharge areas, primarily by evapotranspiration and seepage to underlying aquifers. The spatial distribution of historical mean annual total recharge did not vary between landscape units, as suggested in a previous study. Similarly, total recharge did not correlate significantly with mean annual rainfall, mean annual water table depth, or the surficial soil properties of percent clay and bulk density. Total recharge did correlate significantly with the surficial soil properties of percent sand and percent silt. ?? Springer-Verlag 2007.
Arnoux, Marie; Barbecot, Florent; Gibert-Brunet, Elisabeth; Gibson, John; Noret, Aurélie
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
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
Risser, Dennis W.
This report presents the results of a study by the U.S. Geological Survey, in cooperation with the Pennsylvania Geological Survey, to illustrate a water-budget method for mapping the spatial distribution of ground-water recharge for a 76-square-mile part of the Jordan Creek watershed, northwest of Allentown, in Lehigh County, Pennsylvania. Recharge was estimated by using the Hydrological Evaluation of Landfill Performance (HELP) water-budget model for 577 landscape units in Jordan Creek watershed, delineated on the basis of their soils, land use/land cover, and mean annual precipitation during 1951-2000. The water-budget model routes precipitation falling on each landscape unit to components of evapotranspiration, surface runoff, storage, and vertical percolation (recharge) for a five-layer soil column on a daily basis. The spatial distribution of mean annual recharge during 1951-2000 for each landscape unit was mapped by the use of a geographic information system. Recharge simulated by the water-budget model in Jordan Creek watershed during 1951-2000 averaged 12.3 inches per year and ranged by landscape unit from 0.11 to 17.05 inches per year. Mean annual recharge during 1951-2000 simulated by the water-budget model was most sensitive to changes to input values for precipitation and runoff-curve number. Mean annual recharge values for the crop, forest, pasture, and low-density urban land-use/land-cover classes were similar (11.2 to 12.2 inches per year) but were substantially less for high-density urban (6.8 inches per year), herbaceous wetlands (2.5 inches per year), and forested wetlands (1.3 inches per year). Recharge rates simulated for the crop, forest, pasture, and low-density urban land-cover classes were similar because those land-use/land-cover classes are represented in the model with parameter values that either did not significantly affect simulated recharge or tended to have offsetting effects on recharge. For example, for landscapes with forest land
Understanding the past to interpret the future: comparison of simulated groundwater recharge in the upper Colorado River basin (USA) using observed and general-circulation-model historical climate data
Tillman, Fred D.; Gangopadhyay, Subhrendu; Pruitt, Tom
In evaluating potential impacts of climate change on water resources, water managers seek to understand how future conditions may differ from the recent past. Studies of climate impacts on groundwater recharge often compare simulated recharge from future and historical time periods on an average monthly or overall average annual basis, or compare average recharge from future decades to that from a single recent decade. Baseline historical recharge estimates, which are compared with future conditions, are often from simulations using observed historical climate data. Comparison of average monthly results, average annual results, or even averaging over selected historical decades, may mask the true variability in historical results and lead to misinterpretation of future conditions. Comparison of future recharge results simulated using general circulation model (GCM) climate data to recharge results simulated using actual historical climate data may also result in an incomplete understanding of the likelihood of future changes. In this study, groundwater recharge is estimated in the upper Colorado River basin, USA, using a distributed-parameter soil-water balance groundwater recharge model for the period 1951-2010. Recharge simulations are performed using precipitation, maximum temperature, and minimum temperature data from observed climate data and from 97 CMIP5 (Coupled Model Intercomparison Project, phase 5) projections. Results indicate that average monthly and average annual simulated recharge are similar using observed and GCM climate data. However, 10-year moving-average recharge results show substantial differences between observed and simulated climate data, particularly during period 1970-2000, with much greater variability seen for results using observed climate data.
Bates, B. L.; McIntosh, J. C.
The Powder River Basin (PRB), located in northeastern Wyoming (USA), is a principle producer of coal bed methane world-wide. The basin contains an extensive natural gas well network, which combined with past studies, facilitates a unique opportunity to study the coupling of hydrology and microbial methane generation. Microbes generate methane via two metabolic pathways, acetate fermentation and carbon dioxide reduction, which can be distinguished using C and H isotopes of CO2, CH4, and H2O, and DNA studies. The relative importance of these pathways is primarily dependent on the bioavailability of organic matter, presence of nutrients, salinity, and microbial community structure. Previous studies by Flores et al. (2008) observed the dominance of acetoclastic methanogenesis in select areas near the basin margins where the coal zones were burned (clinker deposits). Methane generated via CO2 reduction is dominant at depth throughout the basin. We hypothesize that the spatial and depth distribution of CO2 versus acetate -utilizing methanogens in the PRB is related to groundwater recharge rates, residence times, proximity to clinker deposits, and nutrient supply. To test this hypothesis, we collected co-produced groundwaters and natural gas from 32 wells, along two transects across the basin that were parallel to regional hydrologic gradients. Four shallow groundwater samples were also collected from a surface coal mine. Oxygen and hydrogen isotopes, tritium, and carbon-14 were used to estimate apparent groundwater ages and recharge rates. Variations in ion concentrations (e.g. Cl, SO4, NO3, NO2, NH4, PO4, SO4, acetate) were coupled to age tracers to determine the effects of recharge rates and flowpaths on nutrient transport and cycling, which may in turn affect metabolic pathways for methane generation in organic-rich aquifers.
Zomlot, Z.; Verbeiren, B.; Huysmans, M.; Batelaan, O.
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
Uribe, Javier; Muñoz, José F.; Gironás, Jorge; Oyarzún, Ricardo; Aguirre, Evelyn; Aravena, Ramón
Closed basins are catchments whose drainage networks converge to lakes, salt flats or alluvial plains. Salt flats in the closed basins in arid northern Chile are extremely important ecological niches. The Salar del Huasco, one of these salt flats located in the high plateau (Altiplano), is a Ramsar site located in a national park and is composed of a wetland ecosystem rich in biodiversity. The proper management of the groundwater, which is essential for the wetland function, requires accurate estimates of recharge in the Salar del Huasco basin. This study quantifies the spatio-temporal distribution of the recharge, through combined use of isotopic characterization of the different components of the water cycle and a rainfall-runoff model. The use of both methodologies aids the understanding of hydrological behavior of the basin and enabled estimation of a long-term average recharge of 22 mm/yr (i.e., 15 % of the annual rainfall). Recharge has a high spatial variability, controlled by the geological and hydrometeorological characteristics of the basin, and a high interannual variability, with values ranging from 18 to 26 mm/yr. The isotopic approach allowed not only the definition of the conceptual model used in the hydrological model, but also eliminated the possibility of a hydrogeological connection between the aquifer of the Salar del Huasco basin and the aquifer that feeds the springs of the nearby town of Pica. This potential connection has been an issue of great interest to agriculture and tourism activities in the region.
Ait El Mekki, Ouassil; Laftouhi, Nour-Eddine; Hanich, Lahoucine
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.
Wang, Shiqin; Zheng, Wenbo; Currell, Matthew; Yang, Yonghui; Zhao, Huan; Lv, Mengyu
Identification of different nitrate sources in groundwater is challenging in areas with diverse land use and multiple potential inputs. An area with mixed land-uses, typical of the piedmont-plain recharge area of the North China Plain, was selected to investigate different nitrate sources and the impact of land use on nitrate distribution in groundwater. Multiple environmental tracers were examined, including major ions, stable isotopes of water (δ 2 H-H 2 O, δ 18 O-H 2 O) and nitrate (δ 15 N-NO 3 - and δ 18 O-NO 3 - ). Groundwater was sampled from four land-use types; natural vegetation (NV), farmland (FL), economic forestland (EF) and residential areas (RA). A mixing model using δ 18 O and Cl - concentrations showed that groundwater recharge predominantly comprises precipitation and lateral groundwater flow from areas of natural vegetation in the upper catchment, while irrigation return water and wastewater from septic tanks were major inputs in farmland and residential areas, respectively. Land use variation is the major contributing factor to different nitrate concentrations. In total, 80%, 49% and 86% of samples from RA, FL and EF, respectively exceeded the WHO standard (50mg/L NO 3 - ), compared to 6.9% of samples from NV. Isotopes of δ 15 N-NO 3 - and δ 18 O-NO 3 - verified that nitrate in groundwater of the NV (with δ 15 N ranging from 1.7‰ to 4.7‰) was sourced from soil and precipitation. Examination of δ 15 N-NO 3 - vs δ 18 O-NO 3 - values along with multivariate statistical analysis (principle component and cluster analysis) helped identify sources with overlapping isotopic values in other land-use areas (where δ 15 N values range from 2.5‰ to 10.2‰). Manure and septic waste were dominant sources for most groundwater with high NO 3 - and Cl - concentrations in both farmland and residential areas. The lack of de-nitrification and fact that the area is a recharge zone for the North China Plain highlight the importance of controlling
Alaoui, Abdallah; Eugster, Werner
A simple method for calibrating the dual-porosity MACRO model via in situ TDR measurements during a brief infiltration run (2.8 h) is proposed with the aim of estimating local groundwater recharge (GR). The recharge was modeled firstly by considering the entire 3 m of unsaturated soil, and secondly by considering only the topsoil to the zero-flux plane (0-0.70 m). The modeled recharge was compared against the GR obtained from field measurements. Measured GR was 313 mm during a 1-year period (15 October 1990-15 October 1991). The best simulation results were obtained when considering the entire unsaturated soil under equilibrium conditions excluding the macropore flow effect (330 mm), whereas under non-equilibrium conditions GR was overestimated (378 mm). Sensitivity analyses showed that the investigation of the topsoil is sufficient in estimating local GR in this case, since the water stored below this depth appears to be below the typical rooting depth of the vegetation and is not available for evapotranspiration. The modeled recharge under equilibrium conditions for the 0.7-m-topsoil layer was found to be 364 mm, which is in acceptable agreement with measurements. Une méthode simple pour la calibration du modèle à double porosité MACRO par des mesures TDR in situ durant un bref essai d'infiltration (2.8 h) a été proposée pour l'estimation locale de la recharge de la nappe (RN). La RN a été d'abord simulée en tenant compte de toute la zone non saturée (3 m) et ensuite, en considérant uniquement la couverture du sol entre zéro et le plan du flux nul (0.70 m). La RN simulée a été comparée à la RN observée. La RN mesurée durant une année (15 octobre 1990-15 octobre 1991) était de 313 mm. Les meilleures simulations ont été obtenues en tenant compte de toute la zone non saturée sous les conditions d'équilibre excluant le flux préférentiel (330 mm). Sous les conditions de non équilibre, la RN a été surestimée (378 mm). Les analyses de
Engott, John A.; Johnson, Adam G.; Bassiouni, Maoya; Izuka, Scot K.; Rotzoll, Kolja
Owing mainly to projected population growth, demand for freshwater on the Island of Oʻahu is expected to increase by about 26 percent between 2010 and 2030, according to the City and County of Honolulu. Estimates of groundwater recharge are needed to evaluate the availability of fresh groundwater. For this study, a water-budget model with a daily computation interval was developed and used to estimate the spatial distribution of recharge on Oʻahu 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 Oʻahu is about 660 million gallons per day, or about 36 percent of precipitation (rainfall and fog interception). Recharge for average climate conditions is about 34 percent of total water inflow, which consists of precipitation, irrigation, septic leachate, water-main leakage, and seepage from reservoirs and cesspools. Recharge is high along the crest of the Koʻolau Range, reaching as much as about 180 inches per year in the north-central part of the range. Recharge is much lower outside of the mountainous areas of the island, commonly less than 5 inches per year in unirrigated areas. The island-wide estimate of groundwater recharge for average climate conditions from this study is within 1 percent of the recharge estimate used in the 2008 State of Hawaiʻi Water Resource Protection Plan, which divides the Island of Oʻahu into 23 aquifer systems for groundwater management purposes. To facilitate direct comparisons with this study, these 23 aquifer systems were consolidated into 21 aquifer systems. Recharge estimates from this study are higher for 12 of the aquifer-system areas and lower for 9. Differences in mean rainfall distribution and the inclusion of irrigation in this study are the primary reasons for discrepancies in recharge estimates between this study and the 2008 Hawaiʻi Water Resources Protection Plan. For
Lizarraga, Joy S.; Ockerman, Darwin J.
The U.S. Geological Survey (USGS), in cooperation with the San Antonio River Authority, the Evergreen Underground Water Conservation District, and the Goliad County Groundwater Conservation District, configured, calibrated, and tested a watershed model for a study area consisting of about 2,150 square miles of the lower San Antonio River watershed in Bexar, Guadalupe, Wilson, Karnes, DeWitt, Goliad, Victoria, and Refugio Counties in south-central Texas. The model simulates streamflow, evapotranspiration (ET), and groundwater recharge using rainfall, potential ET, and upstream discharge data obtained from National Weather Service meteorological stations and USGS streamflow-gaging stations. Additional time-series inputs to the model include wastewater treatment-plant discharges, withdrawals for cropland irrigation, and estimated inflows from springs. Model simulations of streamflow, ET, and groundwater recharge were done for 2000-2007. Because of the complexity of the study area, the lower San Antonio River watershed was divided into four subwatersheds; separate HSPF models were developed for each subwatershed. Simulation of the overall study area involved running simulations of the three upstream models, then running the downstream model. The surficial geology was simplified as nine contiguous water-budget zones to meet model computational limitations and also to define zones for which ET, recharge, and other water-budget information would be output by the model. The model was calibrated and tested using streamflow data from 10 streamflow-gaging stations; additionally, simulated ET was compared with measured ET from a meteorological station west of the study area. The model calibration is considered very good; streamflow volumes were calibrated to within 10 percent of measured streamflow volumes. During 2000-2007, the estimated annual mean rainfall for the water-budget zones ranged from 33.7 to 38.5 inches per year; the estimated annual mean rainfall for the entire
Brady, Brendan W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
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.
Wei, Ya-ni; Fan, Wen; Cao, Yanbo
Land subsidence due to aquifer-system compaction accompanying groundwater extraction is a global hazard. Rising urban construction and groundwater demand necessitate increased awareness and better understanding of the geological problem. Motivated by the lack of laboratory-scale studies on this issue, an experimental investigation on the newly developed Tongchuan region, China, is presented. The study addresses the deformation behaviors of three soil samples, with the lithology of silty clay, silt, and fine sand, under the conditions of groundwater withdrawal and recharge using the GDS Consolidation Testing System. Results indicate that all three samples were characterized by elastic-plastic deformation under the conditions of withdrawing and recharging. The vertical deformation of the silty clay in the aquitard above the first confined aquifer was larger than those of the other two samples, and its deformation is a gradual and long process; thus, considerable attention should be paid to deformation in this aquitard due to the apparent creep effect and tiny rebound deformation. However, the settlement of the fine sand in the second confined aquifer cannot be ignored due to the great thickness of the aquifer. For the same soil, as the pore-water pressure declined, the unit rate of vertical deformation decreased gradually, whereas the creep effect of deformation in the later declining stage of pore-water pressure was more apparent than that in the former declining stage. These observations are highly important to the local government, which is developing measures to prevent and control subsidence.
Water quality and environmental isotopic analyses of ground-water samples collected from the Wasatch and Fort Union Formations in areas of coalbed methane development : implications to recharge and ground-water flow, eastern Powder River basin, Wyoming
Bartos, Timothy T.; Ogle, Kathy Muller
Chemical analyses of ground-water samples were evaluated as part of an investigation of lower Tertiary aquifers in the eastern Powder River Basin where coalbed methane is being developed. Ground-water samples were collected from two springs discharging from clinker, eight monitoring wells completed in the Wasatch aquifer, and 13 monitoring or coalbed methane production wells completed in coalbed aquifers. The ground-water samples were analyzed for major ions and environmental isotopes (tritium and stable isotopes of hydrogen and oxygen) to characterize the composition of waters in these aquifers, to relate these characteristics to geochemical processes, and to evaluate recharge and ground-water flow within and between these aquifers. This investigation was conducted in cooperation with the Wyoming State Engineer's Office and the Bureau of Land Management. Water quality in the different aquifers was characterized by major-ion composition. Samples collected from the two springs were classified as calcium-sulfate-type and calcium-bicarbonate-type waters. All ground-water samples from the coalbed aquifers were sodium-bicarbonate-type waters as were five of eight samples collected from the overlying Wasatch aquifer. Potential areal patterns in ionic composition were examined. Ground-water samples collected during this and another investigation suggest that dissolved-solids concentrations in the coalbed aquifers may be lower south of the Belle Fourche River (generally less than 600 milligrams per liter). As ground water in coalbed aquifers flows to the north and northwest away from an inferred source of recharge (clinker in the study area), dissolved-solids concentrations appear to increase. Variation in ionic composition in the vertical dimension was examined qualitatively and statistically within and between aquifers. A relationship between ionic composition and well depth was noted and corroborates similar observations by earlier investigators in the Powder River
João Paulo Lobo Ferreira
Full Text Available In the Algarve southern Portugal region, Managed Aquifer Recharge (MAR research activities have been developed to provide not only water surplus storage in aquifers during wet years, focusing in the Querença-Silves aquifer (FP6 ASEMWATERNet Coordination Action, but also groundwater quality rehabilitation in the Campina de Faro aquifer (FP6 Gabardine Project. Following MAR research potentialities in southern Portugal, this paper describes the objectives, conceptual demonstration, background and capabilities of one of the selected Circum-Mediterranean pilot sites (in Portugal that will be researched in the new FP7-ENV-2013-WATER-INNO-DEMO MARSOL project, which started Dec. 1st, 2013. In the Algarve pilot site, several case-study areas will be located in the Querença-Silves aquifer and in the Campina de Faro aquifer.
Artificial recharge of surface water to aquifer Tereza Čechová, Geotechnologie Abstract: The bachelor thesis is devoted to groundwater recharge. The source of groundwater is infiltration of atmospheric precipitation. The study deals with the use of controlled artificial recharge in the Czech Republic and the other countries in the Word.
[ABSTRACT] In this study, a simple water balance model linking with Green-Ampt model was improved on basis of measured results in a semiarid upland, Tanzania, and it was applied to local areas under different soil or rainfall conditions in a same basin. In spite of only three parameters with regard to the part under the ground in this model, the calculated value simulated well the measured value. In this model, the critical rainfall which groundwater recharge occurs was determined by the soil...
Storck, Florian R; Schmidt, Carsten K; Wülser, Richard; Brauch, Heinz-Jürgen
Drinking water is often produced from surface water by riverbank filtration (RBF) or artificial groundwater recharge (AGR). In this study, an AGR system was exemplarily investigated and results were compared with those of RBF systems, in which the effects of redox milieu, temperature and surface water discharge on the cleaning efficiency were evaluated. Besides bulk parameters such as DOC (dissolved organic carbon), organic trace pollutants including iodinated X-ray contrast media, personal care products, complexing agents, and pharmaceuticals were investigated. At all studied sites, levels of TOC (total organic carbon), DOC, AOX (adsorbable organic halides), SAC (spectral absorption coefficient at 254 nm), and turbidity were reduced significantly. DOC removal was stimulated at higher groundwater temperatures during AGR. Several substances were generally easily removable during both AGR and RBF, regardless of the site, season, discharge or redox regime. For some more refractory substances, however, removal efficiency turned out to be significantly influenced by redox conditions.
Meyer, Scott C; Lin, Yu-Feng; Roadcap, George S
We employed the ArcGIS plug-in package PRO-GRADE (Lin et al. 2009), developed for zonation of recharge/discharge (R/D) for modeling two-dimensional aquifer systems, to develop alternative R/D zonations for an existing three-dimensional groundwater flow model of a complex hydrogeologic setting. Our process began by intersecting PRO-GRADE output with the existing model's 4-zone R/D representation to develop a model having 12 R/D zones (R12) and then calibrating the resulting model using PEST. We then revised the R12 zonation using supplementary GIS data to develop a 51-zone R/D zonation (R51). From R51, we developed a series of daughter models having 40, 30, 28, and 18 R/D zones by removing zones from R51 if calibration resulted in little change in the zone's starting R/D rate and/or if the model was insensitive to the zone's R/D rate. For these models (R40N, R30N, R28N, and R18N), we used the ArcGIS Nibble tool to rapidly and consistently reassign model cells within eliminated zones of R51 to the zone of the nearest model cell in a retained zone having the same starting value. R12, R51, R40N, R30N, R28N, and R18N are all more accurate than the original model (R4), although improvements relative to stream discharge targets exceeded improvements relative to head targets. The models also executed with better numerical stability and less mass balance discrepancy than R4. These improvements demonstrate that R/D estimation in a complex shallow three-dimensional steady-state model can be improved with PRO-GRADE estimates of R/D when guided by calibration statistics and supplemental geographic data. © 2011, The Author(s). Ground Water © 2011, National Ground Water Association.
Boonstra, J.; Bhutta, M.N.; Rizvi, S.A.
To assess the drainable surplus of an irrigated area, a methodology based on a groundwater-balance approach was developed and applied in Schedule I-B of the Fourth Drainage Project near Faisalabad in Pakistan. To determine the seasonal net recharge in this area, a numerical groundwater model was run
Visser, A.; Broers, H.P.; Grift, B. van der; Bierkens, M.F.P.
Recent EU legislation is directed to reverse the upward trends in the concentrations of agricultural pollutants in groundwater. However, uncertainty of the groundwater travel time towards the screens of the groundwater quality monitoring networks complicates the demonstration of trend reversal. We
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
Senior, Lisa A.; Goode, Daniel J.
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
Heilweil, Victor M.; Susong, David D.; Gardner, Philip M.; Watt, Dennis E.
Sand Hollow, Utah, is the site of a surface-water reservoir completed in March 2002, which is being operated by the Washington County Water Conservancy District primarily as an aquifer storage and recovery project. The reservoir is an off-channel facility receiving water from the Virgin River, diverted near the town of Virgin, Utah. It is being operated conjunctively, providing both surface-water storage and artificial recharge to the underlying Navajo aquifer. The U.S. Geological Survey and the Bureau of Reclamation conducted a study to document baseline ground-water conditions at Sand Hollow prior to the operation of the reservoir and to evaluate changes in ground-water conditions caused by the reservoir.Pre-reservoir age dating using tritium/helium, chlorofluorocarbons, and carbon-14 shows that shallow ground water in the Navajo Sandstone in some areas of Sand Hollow entered the aquifer from 2 to 25 years before sample collection. Ground water in low-recharge areas and deeper within the aquifer may have entered the aquifer more than 8,000 years ago. Ground-water levels in the immediate vicinity of Sand Hollow Reservoir have risen by as much as 80 feet since initial filling began in March 2002. In 2005, ground water was moving laterally away from the reservoir in all directions, whereas the pre-reservoir direction of ground-water flow was predominantly toward the north.Tracers, or attributes, of artificial recharge include higher specific conductance, higher dissolved-solids concentrations, higher chloride-to-bromide ratios, more-depleted stable isotopes (2H and 18O), and higher total-dissolved gas pressures. These tracers have been detected at observation and production wells close to the reservoir. About 15,000 tons of naturally occurring salts that previously accumulated in the vadose zone beneath the reservoir are being flushed into the aquifer. Except for the shallowest parts of the aquifer, this is generally not affecting water quality, largely because of
Cui, Xianze; Liu, Quansheng; Zhang, Chengyuan; Huang, Yisheng; Fan, Yong; Wang, Hongxing
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.
Wieczorek, Michael; LaMotte, Andrew E.
This tabular data set represents the mean annual natural groundwater recharge, in millimeters, compiled for every MRB_E2RF1catchment of selected Major River Basins (MRBs, Crawford and others, 2006). The source data set is Estimated Mean Annual Natural Ground-Water Recharge in the Conterminous United States (Wolock, 2003). The MRB_E2RF1 catchments are based on a modified version of the U.S. Environmental Protection Agency's (USEPA) ERF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2011). Data were compiled for every MRB_E2RF1 catchment for the conterminous United States covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).
Taylor, Richard G.; Chandler, Richard E.
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
Xie, Xianjun; Wang, Yanxin; Su, Chunli; Duan, Mengyu
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.
Sahu, Paulami; Michael, Holly A; Voss, Clifford I; Sikdar, Pradip K
.... Heavy pumping of groundwater beneath these urban centres, particularly in regions with low natural topographic gradients, such as deltas and floodplains, can fundamentally alter the hydrological system...
Full Text Available Karstic groundwater basins are characterized by both point and diffuse recharge. This paper describes the hydrologic characteristics of point recharge and their influence on recharge estimation for four groundwater basins. Point recharge is highly transient and may occur in relatively short-time periods, yet is capable of recharging a large volume of water, even from a single extreme rainfall event. Preferential groundwater flows are observed in karst aquifers with local fresher water pockets of low salinity that develop around point recharge sources. Measurable fresh water plumes develop only when a large quantity of surface water enters the aquifer as a point recharge. In fresh water plumes, the difference in chloride concentrations in diffuse and point recharge zones decreases as the plumes become enriched through mixing. The relative contributions to total recharge from point sources using the measured gap between groundwater and rainwater chloride in the chloride vs. δ18O plot is not necessarily indicative of sinkholes not directly recharging the aquifer. In karst aquifers, recharge estimation methods based on groundwater age distribution; average annual rainfall and basin average chloride in the conventional chloride mass balance (CMB method are questionable due to theoretical limitations and key assumptions of these methods not being met. In point recharge dominant groundwater basins, application of: watertable fluctuation, numerical groundwater modelling, Darcy flow calculation or water budget methods are more suitable for recharge estimation as they are independent of the particular mode of recharge. The duality of the recharge mechanism in karst aquifers suggests that modification to the CMB method may be required to include both point and diffuse recharge components.
Aly, A I; Froehlich, K; Nada, A; Awad, M; Hamza, M; Salem, W M
Oxygen-18 ((18)0) and deuterium isotopes were used to estimate the evaporation from the Aswan High Dam Lake and to investigate the inter-relation between the lake water and adjacent groundwater.According to stable isotopic analysis of samples taken in 1988 and 1989, the lake can be divided into two sections. In the first section extending between Abu Simbel and a point between EI-Alaki and Krosko, a remarkable vertical gradient of (18)0 and deuterium isotopic composition was observed. The second northern sector extending to the High Dam is characterised by a lower vertical isotopic gradient. In this sector in general, higher values of (18)O and deuterium contents were found at the top and lower values at the bottom. Also a strong horizontal increase of the heavy isotope content was observed. Thus, in the northern section evaporation is of dominating influence on the isotopic composition of the lake water.With the help of an evaporation pan experiment it was possible to calibrate the evaporative isotope enrichment in the lake and to facilitate a preliminary estimate of evaporative losses of lake water. The evaporation from the lake was estimated to be about 19% of the input water flow rate.The groundwater around the lake was investigated and samples from production wells and piezometers were subjected to isotopic analysis. The results indicate that recent recharge to the groundwater aquifer is limited to wells near to the lake and up to a maximum distance of about 10 km. The contribution of recent Nile water to the groundwater in these wells was estimated to range between 23 and 70%. Beyond this distance, palaeowater was observed with highly depleted deuterium and (18)0 contents, which was also confirmed by 14c dating. The age of palaeo groundwater in this area can reach values of more than 26,000 years.Recommendations are given for efficient water management of the lake water.
Ehlers, L; Herrmann, F; Blaschek, M; Duttmann, R; Wendland, F
This study examines the impact of changing climatic conditions on groundwater recharge in the Riu Mannu catchment in southern Sardinia. Based on an ensemble of four downscaled and bias corrected combinations of Global and Regional Climate Models (GCM-RCMs), the deterministic distributed water balance model mGROWA was used to simulate long-term mean annual groundwater recharge in the catchment for four 30-year periods between 1981 and 2100. The four employed GCM-RCM combinations project an adverse climatic development for the study area: by the period 2071-2100, annual rainfall will decrease considerably, while grass reference evapotranspiration will rise. Accordingly, ensemble results for our base scenario showed a climate-induced decrease in the median of annual groundwater recharge in areas covered by Macchia from 42-48mm/a to 25-35mm/a between the periods 1981-2010 and 2071-2100, corresponding to a reduction of 17-43%. To take into account the influence of additional plant available water storage in weathered bedrock on groundwater recharge generation, the model was extended by a regolith zone for regions covered by Mediterranean Macchia. In a set of model runs ("scenarios"), parameter values controlling the water storage capacity of this zone were increased step-wise and evaluated by comparison to the base scenario to analyze the sensitivity of the model outcome to these changes. The implementation of a regolith zone had a considerable impact on groundwater recharge and resulted in a decrease of the median in annual groundwater recharge: by 2071-2100, the 35% scenario (available water content in the regolith of 3.9 to 5.7vol.%) showed a reduction of 67-82% as compared to the period 1981-2010 in the base scenario. In addition, we also examined the influence of changes in the crop coefficients (Kc) as well as different soil texture distributions on simulated groundwater recharge. Copyright © 2015 Elsevier B.V. All rights reserved.
Friesz, Paul J.; Stone, Janet R.
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.
Li, Qiang; Xing, Zisheng; Danielescu, Serban; Li, Sheng; Jiang, Yefang; Meng, Fan-Rui
Estimation of baseflow and groundwater recharge rates is important for hydrological analysis and modelling. A new approach which combines recursive digital filter (RDF) model with conductivity mass balance (CMB) method was considered to be reliable for baseflow separation because the combined method takes advantages of the reduced data requirement for RDF method and the reliability of CMB method. However, it is not clear what the minimum data requirements for producing acceptable estimates of the RDF model parameters are. In this study, 19-year record of stream discharge and water conductivity collected from the Black Brook Watershed (BBW), NB, Canada were used to test the combined baseflow separation method and assess the variability of parameters in the model over seasons. The data requirements and potential bias in estimated baseflow index (BFI) were evaluated using conductivity data for different seasons and/or resampled data segments at various sampling durations. Results indicated that the data collected during ground-frozen season are more suitable to estimate baseflow conductivity (Cbf) and data during snow-melting period are more suitable to estimate runoff conductivity (Cro). Relative errors of baseflow estimation were inversely proportional to the number of conductivity data records. A minimum of six-month discharge and conductivity data is required to obtain reliable parameters for current method with acceptable errors. We further found that the average annual recharge rate for the BBW was 322 mm in the past twenty years.
Howard and Lloyd (1979) have shown that daily values for rainfall and potential evapotranspiration are required in estimating recharge with a soil water balance model. However, available data may not be daily but weekly or even monthly. This is true for potential evapotranspiration data which are usually derived from pan evaporation data. This paper examines the effect of using distributed weekly, 10-daily or monthly potential evapotranspiration values rather than the actual daily values in e...
Consideration of the thermal and volatile evolution of a water-rich Mars suggests that, if the inventory of H2O exceeds the pore volume of the cryosphere by more than a few percent, then a planetary-scale subpermafrost groundwater system will necessarily result - a system whose existence may have played a critical role in the long-term climatic and hydrologic evolution of the planet. Under the climatic conditions that have prevailed throughout most of Martian geologic history, any water discharged by outflow channel activity should have frozen, sublimed away, and been transported by the atmosphere to the planet's obliquity-dependent coldtraps. Given an initially ice-saturated cryosphere, the deposition and retention of ice anywhere on the planet will result in the rise of the melting isotherm at the base of the cryosphere, the onset of basal melting, and the downward percolation of meltwater into the underlying global aquifer, thereby recharging the reservoir of groundwater from which the outflow channels formed. Although thick, ice-rich deposits may have accumulated in a variety of locations under different obliquity conditions, the only persuasive geomorphic evidence for the basal melting of such deposits lies in the Dorsa Argentia Formation (DAF), near the South Pole. The Martian outflow channels appear to have had diverse origins, including: the catastrophic discharge of subpermafrost groundwater following the disruption of the cryosphere, the melting of near-surface ground ice by local magmatic activity, the breaching of surface lakes, and erosion by low-viscosity lavas. Of these possibilities, the abrupt emergence of most outflow channels from regions of collapsed and disrupted terrain, along the dichotomy boundary, suggests that they were formed by a massive discharge of groundwater from a subpermafrost aquifer, whose elevated water table was maintained in hydraulic disequilibrium with the lower-lying northern plains by its confinement beneath kilometers
W. Dawes; Ali, R.; Varma, S.; I. Emelyanova; Hodgson, G; Mcfarlane, D
The groundwater resource contained within the sandy aquifers of the Swan Coastal Plain, south west Western Australia, provides approximately 60% 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 rai...
W. Dawes; Ali, R.; Varma, S.; I. Emelyanova; Hodgson, G; Mcfarlane, D
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 rai...
Yan, Yulin; Ma, Mengsi; Liu, Xiang; Ma, Weifang; Li, Yangyao
When groundwater is recharged with reclaimed water, the presence of trace amounts of biorefractory pentabromodiphenyl ether (PBDE, specifically BDE-99) might cause potential groundwater pollution. A laboratory-scale column was designed to investigate the distribution of the community of archaea in this scenario and the associated anaerobic degradation of BDE-99. The concentration of BDE-99 decreased significantly as soil depth increased, and fluorescence in situ hybridization (FISH) analysis suggested that archaea exerted significant effects on the biodegradation of PBDE. Through 454 pyrosequencing of 16s rRNA genes, we found that the distribution and structure of the archaeal community associated with anaerobic degradation of BDE-99 in the river-based aquifer media changed significantly between different soil depths. The primary debrominated metabolites varied with changes in the vertically distributed archaeal community. The archaea in the surface layer were dominated by Methanomethylovorans, and the middle layer was mainly composed of Nitrososphaera. Nitrosopumilus and Nitrososphaera were equally abundant in the bottom layer. In addition, Methanomethylovorans abundance depended on the depth of soil, and the relative abundance of Nitrosopumilus increased with increasing depth, which was associated with the oxidation-reduction potential and the content of intermediate metabolites. We propose that Nitrososphaera and Nitrosopumilus might be the key archaeal taxa mediating the biodegradation of BDE-99.
Crandall, Christy A.; Kauffman, Leon J.; Katz, Brian G.; Metz, Patricia A.; McBride, W. Scott; Berndt, Marian P.
Shallow ground water in the north-central Tampa Bay region, Florida, is affected by elevated nitrate concentrations, the presence of volatile organic compounds, and pesticides as a result of groundwater development and intensive urban land use. The region relies primarily on groundwater for drinking-water supplies. Sustainability of groundwater quality for public supply requires monitoring and understanding of the mechanisms controlling the vulnerability of public-supply wells to contamination. A single public-supply well was selected for intensive study based on the need to evaluate the dominant processes affecting the vulnerability of public-supply wells in the Upper Floridan aquifer in the City of Temple Terrace near Tampa, Florida, and the presence of a variety of chemical constituents in water from the well. A network of 29 monitoring wells was installed, and water and sediment samples were collected within the area contributing recharge to the selected public-supply well to support a detailed analysis of physical and chemical conditions and processes affecting the water chemistry in the well. A three-dimensional, steady-state groundwater flow model was developed to evaluate the age of groundwater reaching the well and to test hypotheses on the vulnerability of the well to nonpoint source input of nitrate. Particle tracking data were used to calculate environmental tracer concentrations of tritium and sulfur hexafluoride and to calibrate traveltimes and compute flow paths and advective travel times in the model area. The traveltime of particles reaching the selected public-supply well ranged from less than 1 day to 127.0 years, with a median of 13.1 years; nearly 45 percent of the simulated particle ages were less than about 10 years. Nitrate concentrations, derived primarily from residential/commercial fertilizer use and atmospheric deposition, were highest (2.4 and 6.11 milligrams per liter as nitrogen, median and maximum, respectively) in shallow
Braids, Olin C.; Gillies, Nola P.
Presents a literature review of groundwater quality covering publications of 1977. This review includes: (1) sources of groundwater contamination; and (2) management of groundwater. A list of 59 references is also presented. (HM)
GHULAM SHABIR SOLANGI
Full Text Available A study has been conducted in the command area of Gadeji minor, Sindh, Pakistan to compute the amount of net groundwater recharge and its effect on sustainable irrigated agriculture. In this connection, Water budget equation was used and three groundwater recharging components along with one discharging component were computed for both Rabi and Kharif crop seasons for the period (2001-2013. Data shows that groundwater is rising at rapid rate during the Kharif season. The percolation rate through cropped fields is the major recharge component; accounting for 81% in the total mean recharge of 8.42 million m3, moreover the rice area is the major contributor to net groundwater recharge during Kharif season. The contributions of canal seepage and rainfall are estimated to be 16 and 04% respectively for the above period. However, during the Rabi season groundwater is rising at low rate where canal seepage is the major recharging component with an average contribution of 48% in the total mean recharge of 2.32 million m3, the contribution of deep percolation from cropped fields is estimated to be 47% as compared to the rainfall of only 05%. Survey shows non-functionality of most of the tubewells, groundwater withdrawal is not sufficient to fully offset groundwater recharge which has increased water table and caused waterlogging and soil salinity in more than 40% of agricultural land. To overcome this rising water table problem, it is recommended: to change existing cropping pattern (i.e. minimize or no cultivation of rice crop, lining of minor and all its watercourses, adopt salt tolerant crops and increase groundwater withdrawals by operating tube-wells on emergency basis.
Winograd, Isaac J.; Riggs, Alan C.; Coplen, Tyler B.
A comparison of the stable-isotope signatures of spring waters, snow, snowmelt, summer (July thru September) rain, and cool season (October thru June) rain indicates that the high-intensity, short-duration summer convective storms, which contribute approximately a third of the annual precipitation to the Spring Mountains, provide only a small fraction (perhaps 10%) of the recharge to this major upland in southern Nevada, USA. Late spring snowmelt is the principal means of recharging the fractured Paleozoic-age carbonate rocks comprising the central and highest portion of the Spring Mountains. Daily discharge measurements at Peak Spring Canyon Creek during the period 1978-94 show that snowpacks were greatly enhanced during El Niño events. Résumé La comparaison des signatures isotopiques stables des eaux de sources, de neige, de fonte de neige, des pluies d'été (juillet à septembre) et de saison froide (octobre à juin) montre que les précipitations convectives d'été de forte intensité et de courte durée, apportant un tiers des précipitations annuelles reçues par les Monts Spring, ne participent que pour une faible part (10%) à la recharge de cette importante zone d'altitude du sud du Nevada (États-Unis). La fonte tardive de la neige au printemps constitue l'essentiel de la recharge des roches carbonatées fracturées d'âge paléozoïque formant la partie centrale et la plus haute des Monts Spring. Les données journalières de débit sur la rivière du canyon de Peak Spring, entre 1978 et 1994, montrent que les hauteurs de neige ont été plus élevées pendant les événements El Niño. Resumen La comparación entre las marcas isotópicas de aguas de manantiales, nieve, deshielo, lluvias de verano (julio a septiembre) y resto de lluvias (octubre a junio) indican que las tormentas de verano, de corta duración y gran intensidad, las cuales suponen alrededor de un tercio de la precipitación total anual en las Spring Mountains, proporcionan sólo una
Sastre Beceiro, M.
This article examines the artificial aquifer recharge regulation in the EC and Spanish Law (State law and Andalusian law). Furthermore, it also deals with artificial aquifer recharge in Cuenca's present hydrologic plans. Next, the principal problems about artificial aquifer recharge will be described. These are: lack of a unitary regulation, lack of a homogenous definition of artificial recharge and its types, operation cost finance and at whose expense it should go, etc. We reach the conclusion that there is a need of a specific, unified and systematic regulation about artificial aquifer recharge. This regulation could comprise the following aspects: the concept for artificial aquifer recharge, types of recharge (sorted by the origin of the water and the technique that is used), recharge authorizations and conditions to be included in the title, necessary building work to recharge and its financial mechanisms (depending on its public or private condition), rights over the recharged water, supporting document for the use of the recharged water, transfer possibilities, etc. Finally, the positive effects of artificial aquifer recharges are analyzed: elevation of the piezo metric level in the aquifers that have been declared as overexploited or that are in danger of being so, wetland restoration, restraint of marine intrusion, subterranean water pollution reduction, etc. (Author) 9 refs.
Full Text Available The atmospheric chloride mass balance (CMB method was used to estimate net aquifer recharge in Las Cañadas Caldera, an endorheic summit aquifer area about 2000 m a.s.l. with negligible surface runoff, which hosts the largest freshwater reserve in Tenerife Island, Canary Islands, Spain. The wet hydrological year 2005–2006 was selected to compare yearly atmospheric chloride bulk deposition and average chloride content in recharge water just above the water table, both deduced from periodical sampling. The potential contribution of chloride to groundwater from endogenous HCl gas may invalidate the CMB method. The chloride-to-bromide molar ratio was an efficient tracer used to select recharge water samples having atmospheric origin of chloride. Yearly net aquifer recharge was 631 mm year−1, i.e., 69% of yearly precipitation. This result is in agreement with potential aquifer recharge estimated through an independent lumped-parameter rainfall-runoff model operated by the Insular Water Council of Tenerife. This paper illustrates basic procedures and routines to use the CMB method for aquifer recharge in active volcanic oceanic islands having sparse-data coverage and groundwater receiving contribution of endogenous halides.
Mirus, Benjamin B.; Nimmo, J.R.
The impact of preferential flow on recharge and contaminant transport poses a considerable challenge to water-resources management. Typical hydrologic models require extensive site characterization, but can underestimate fluxes when preferential flow is significant. A recently developed source-responsive model incorporates film-flow theory with conservation of mass to estimate unsaturated-zone preferential fluxes with readily available data. The term source-responsive describes the sensitivity of preferential flow in response to water availability at the source of input. We present the first rigorous tests of a parsimonious formulation for simulating water table fluctuations using two case studies, both in arid regions with thick unsaturated zones of fractured volcanic rock. Diffuse flow theory cannot adequately capture the observed water table responses at both sites; the source-responsive model is a viable alternative. We treat the active area fraction of preferential flow paths as a scaled function of water inputs at the land surface then calibrate the macropore density to fit observed water table rises. Unlike previous applications, we allow the characteristic film-flow velocity to vary, reflecting the lag time between source and deep water table responses. Analysis of model performance and parameter sensitivity for the two case studies underscores the importance of identifying thresholds for initiation of film flow in unsaturated rocks, and suggests that this parsimonious approach is potentially of great practical value.
Michel, Caroline; Joulian, Catherine; Ollivier, Patrick; Nyteij, Audrey; Cote, Rémi; Surdyk, Nicolas; Hellal, Jennifer; Casanova, Joel; Besnard, Katia; Rampnoux, Nicolas; Garrido, Francis
In the context of artificial groundwater recharge, a reactive soil column at pilot-scale (4.5 m depth and 3 m in diameter) fed by treated wastewater was designed to evaluate soil filtration ability. Here, as a part of this project, the impact of treated wastewater filtration on soil bacterial communities and the soil's biological ability for wastewater treatment as well as the relevance of the use of multi-bioindicators were studied as a function of depth and time. Biomass; bacterial 16S rRNA gene diversity fingerprints; potential nitrifying, denitrifying, and sulfate-reducing activities; and functional gene (amo, nir, nar, and dsr) detection were analyzed to highlight the real and potential microbial activity and diversity within the soil column. These bioindicators show that topsoil (0 to 20 cm depth) was the more active and the more impacted by treated wastewater filtration. Nitrification was the main activity in the pilot. No sulfate-reducing activity or dsr genes were detected during the first 6 months of wastewater application. Denitrification was also absent, but genes of denitrifying bacteria were detected, suggesting that the denitrifying process may occur rapidly if adequate chemical conditions are favored within the soil column. Results also underline that a dry period (20 days without any wastewater supply) significantly impacted soil bacterial diversity, leading to a decrease of enzyme activities and biomass. Finally, our work shows that treated wastewater filtration leads to a modification of the bacterial genetic and functional structures in topsoil.
Nasiri, Hossein; Boloorani, Ali Darvishi; Sabokbar, Hassan Ali Faraji; Jafari, Hamid Reza; Hamzeh, Mohamad; Rafii, Yusef
Flood spreading is a suitable strategy for controlling and benefiting from floods. Selecting suitable areas for flood spreading and directing the floodwater into permeable formations are amongst the most effective strategies in flood spreading projects. Having combined geographic information systems (GIS) and multi-criteria decision analysis approaches, the present study sought to locate the most suitable areas for flood spreading operation in the Garabaygan Basin of Iran. To this end, the data layers relating to the eight effective factors were prepared in GIS environment. This stage was followed by elimination of the exclusionary areas for flood spreading while determining the potentially suitable ones. Having closely examined the potentially suitable areas using the Preference Ranking Organization Method for Enrichment Evaluations (PROMETHEE) II and analytic hierarchy process (AHP) methods, the land suitability map for flood spreading was produced. The PROMETHEE II and AHP were used for ranking all the alternatives and weighting the criteria involved, respectively. The results of the study showed that most suitable areas for the artificial groundwater recharge are located in Quaternary Q(g) and Q(gsc) geologic units and in geomorphological units of pediment and Alluvial fans with slopes not exceeding 3%. Furthermore, significant correspondence between the produced map and the control areas, where the flood spreading projects were successfully performed, provided further evidence for the acceptable efficiency of the integrated PROMETHEE II-AHP method in locating suitable flood spreading areas.
Van Roosmalen, Lieke Petronella G; Christensen, Britt S.B.; Sonnenborg, Torben O.
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...... 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...
Rawling, Geoffrey C.; Newton, B. Talon
The Sacramento Mountains and the adjacent Roswell Artesian Basin, in south-central New Mexico (USA), comprise a regional hydrologic system, wherein recharge in the mountains ultimately supplies water to the confined basin aquifer. Geologic, hydrologic, geochemical, and climatologic data were used to delineate the area of recharge in the southern Sacramento Mountains. The water-table fluctuation and chloride mass-balance methods were used to quantify recharge over a range of spatial and temporal scales. Extrapolation of the quantitative recharge estimates to the entire Sacramento Mountains region allowed comparison with previous recharge estimates for the northern Sacramento Mountains and the Roswell Artesian Basin. Recharge in the Sacramento Mountains is estimated to range from 159.86 × 106 to 209.42 × 106 m3/year. Both the location of recharge and range in estimates is consistent with previous work that suggests that ~75 % of the recharge to the confined aquifer in the Roswell Artesian Basin has moved downgradient through the Yeso Formation from distal recharge areas in the Sacramento Mountains. A smaller recharge component is derived from infiltration of streamflow beneath the major drainages that cross the Pecos Slope, but in the southern Sacramento Mountains much of this water is ultimately derived from spring discharge. Direct recharge across the Pecos Slope between the mountains and the confined basin aquifer is much smaller than either of the other two components.
Jordan F. Clark
Full Text Available The application of the cosmogenic radioisotope sulfur-35 (35S as a chronometer near spreading basins is evaluated at two well-established Managed Aquifer Recharge (MAR sites: the Atlantis facility (South Africa and Orange County Water District’s (OCWD’s Kraemer Basin (Northern Orange County, CA, USA. Source water for both of these sites includes recycled wastewater. Despite lying nearer to the outlet end of their respective watersheds than to the headwaters, 35S was detected in most of the water sampled, including from wells found close to the spreading ponds and in the source water. Dilution with 35S-dead continental SO4 was minimal, a surprising finding given its short ~3 month half-life. The initial work at the Atlantis MAR site demonstrated that remote laboratories could be set up and that small volume samples—saline solutions collected after the resin elution step from the recently developed batch method described below—can be stored and transported to the counting laboratory. This study also showed that the batch method needed to be altered to remove unknown compounds eluted from the resin along with SO4. Using the improved batch method, times series measurements of both source and well water from OCWD’s MAR site showed significant temporal variations. This result indicates that during future studies, monthly to semi-monthly sampling should be conducted. Nevertheless, both of these initial studies suggest the 35S chronometer may become a valuable tool for managing MAR sites where regulations require minimum retention times.
Clark, Brian R.; Hart, Rheannon M.; Gurdak, Jason J.
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
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...
Scanlon, Bridget R.; Reedy, Robert C.; Faunt, Claudia C.; Pool, Donald; Uhlman, Kristine
Projected longer-term droughts and intense floods underscore the need to store more water to manage climate extremes. Here we show how depleted aquifers have been used to store water by substituting surface water use for groundwater pumpage (conjunctive use, CU) or recharging groundwater with surface water (managed aquifer recharge, MAR). Unique multi-decadal monitoring from thousands of wells and regional modeling datasets for the California Central Valley and central Arizona were used to assess CU and MAR. In addition to natural reservoir capacity related to deep water tables, historical groundwater depletion further expanded aquifer storage by ˜44 km3 in the Central Valley and by ˜100 km3 in Arizona, similar to or exceeding current surface reservoir capacity by up to three times. Local river water and imported surface water, transported through 100s of km of canals, is substituted for groundwater (≤15 km3 yr-1, CU) or is used to recharge groundwater (MAR, ≤1.5 km3 yr-1) during wet years shifting to mostly groundwater pumpage during droughts. In the Central Valley, CU and MAR locally reversed historically declining water-level trends, which contrasts with simulated net regional groundwater depletion. In Arizona, CU and MAR also reversed historically declining groundwater level trends in active management areas. These rising trends contrast with current declining trends in irrigated areas that lack access to surface water to support CU or MAR. Use of depleted aquifers as reservoirs could expand with winter flood irrigation or capturing flood discharges to the Pacific (0-1.6 km3 yr-1, 2000-2014) with additional infrastructure in California. Because flexibility and expanded portfolio options translate to resilience, CU and MAR enhance drought resilience through multi-year storage, complementing shorter term surface reservoir storage, and facilitating water markets.
Scanlon, Bridget R.; Reedy, Robert C.; Faunt, Claudia; Pool, Donald R.; Uhlman, Kristine;
Projected longer‐term droughts and intense floods underscore the need to store more water to manage climate extremes. Here we show how depleted aquifers have been used to store water by substituting surface water use for groundwater pumpage (conjunctive use, CU) or recharging groundwater with surface water (Managed Aquifer Recharge, MAR). Unique multi‐decadal monitoring from thousands of wells and regional modeling datasets for the California Central Valley and central Arizona were used to assess CU and MAR. In addition to natural reservoir capacity related to deep water tables, historical groundwater depletion further expanded aquifer storage by ~44 km3 in the Central Valley and by ~100 km3 in Arizona, similar to or exceeding current surface reservoir capacity by up to three times. Local river water and imported surface water, transported through 100s of km of canals, is substituted for groundwater (≤15 km3/yr, CU) or is used to recharge groundwater (MAR, ≤1.5 km3/yr) during wet years shifting to mostly groundwater pumpage during droughts. In the Central Valley, CU and MAR locally reversed historically declining water‐level trends, which contrasts with simulated net regional groundwater depletion. In Arizona, CU and MAR also reversed historically declining groundwater level trends in Active Management Areas. These rising trends contrast with current declining trends in irrigated areas that lack access to surface water to support CU or MAR. Use of depleted aquifers as reservoirs could expand with winter flood irrigation or capturing flood discharges to the Pacific (0 – 1.6 km3/yr, 2000–2014) with additional infrastructure in California. Because flexibility and expanded portfolio options translate to resilience, CU and MAR enhance drought resilience through multi‐year storage, complementing shorter term surface reservoir storage, and facilitating water markets.
Silberstein, Richard P.; Dawes, Warrick R.; Bastow, Trevor P.; Byrne, John; Smart, Natalie F.
SummaryThis paper examines the use of a controlled fuel reduction burn in native woodland to increase recharge to a shallow aquifer system for water supply in south-western Australia. Soil moisture trends from neutron probe measurements and watertable dynamics from piezometers under adjacent burned and unburned plots were compared to determine the difference in recharge resulting from the fire. Remotely sensed evapotranspiration (ET) subtracted from rainfall was used to independently estimate groundwater and soil moisture recharge and compare against a physically based model of soil-water fluxes. The use of naturally occurring chemicals (n-alkanes and cycloalkanes) produced in the fire as tracers of the recharge pulse in the winter following the fire was tested. It was found that in the winter following the fire (annual rainfall 701 mm), water storage in the 9 m thick unsaturated zone increased by about 300 mm but recharge to the watertable was only about 60 mm. In the subsequent year (rainfall 630 mm), leaf area index in the burned woodland recovered to be about 10% less than the unburned plot, remotely sensed ET rose above that in the unburned plot and recharge was lower in the burned than unburned plot. This trend continued and, after 3 years, increased ET negated any early recharge gains, and there was a net decrease in recharge resulting from the fire. The combination of water balance measurements, modelling and remote sensing provides a robust method to gain hydrological understanding of recharge mechanisms. Further work is required to refine the use of burn residue chemicals as soil water tracers, particularly in improving instrument design for groundwater sample collection in fine textured soils. As climate continues to change and regions with growing water shortages seek innovative solutions, approaches such as controlled burning may be needed; however, in this example, the approach was unproductive and further the environmental consequences need to be
Coppola, Antonio; Comegna, Alessandro; Dragonetti, Giovanna; Lamaddalena, Nicola; Zdruli, Pandi
bodies. Distributed output of soil pollutant leaching behaviour, with corresponding statistical uncertainties, will be provided and finally visualized in GIS maps. The example pollutants considered cover much of the practical pollution conditions one may found in the reality. Nevertheless, this regional- scale methodology may be applied to any specific pollutants for any soil, climatic and land use conditions. Also, as the approach is built on physically based equations, it may be extended to the predictions of any water and solute storage and fluxes (i.e., groundwater recharge) in the vadose zone. By integrating the scientific results with economic and political considerations, and with advanced information technologies, the NPS-pollution assessment may become a powerful decision support tool for guiding activities involving soil and groundwater resources and, more in general, for managing environmental resources.
Flint, A.L.; Flint, L.E.; Kwicklis, E.M.; Fabryka-Martin, J. T.; Bodvarsson, G.S.
Obtaining values of net infiltration, groundwater travel time, and recharge is necessary at the Yucca Mountain site, Nevada, USA, in order to evaluate the expected performance of a potential repository as a containment system for high-level radioactive waste. However, the geologic complexities of this site, its low precipitation and net infiltration, with numerous mechanisms operating simultaneously to move water through the system, provide many challenges for the estimation of the spatial distribution of recharge. A variety of methods appropriate for arid environments has been applied, including water-balance techniques, calculations using Darcy's law in the unsaturated zone, a soil-physics method applied to neutron-hole water-content data, inverse modeling of thermal profiles in boreholes extending through the thick unsaturated zone, chloride mass balance, atmospheric radionuclides, and empirical approaches. These methods indicate that near-surface infiltration rates at Yucca Mountain are highly variable in time and space, with local (point) values ranging from zero to several hundred millimeters per year. Spatially distributed net-infiltration values average 5 mm/year, with the highest values approaching 20 mm/year near Yucca Crest. Site-scale recharge estimates range from less than 1 to about 12 mm/year. These results have been incorporated into a site-scale model that has been calibrated using these data sets that reflect infiltration processes acting on highly variable temporal and spatial scales. The modeling study predicts highly non-uniform recharge at the water table, distributed significantly differently from the non-uniform infiltration pattern at the surface.
Paces, J.B.; Ludwig, K. R.; Peterman, Z.E.; Neymark, L.A.
Uranium concentrations and 234U/238U ratios in saturated-zone and perched ground water were used to investigate hydrologic flow and downgradient dilution and dispersion in the vicinity of Yucca Mountain, a potential high-level radioactive waste disposal site. The U data were obtained by thermal ionization mass spectrometry on more than 280 samples from the Death Valley regional flow system. Large variations in both U concentrations (commonly 0.6-10 ??g 1-1) and 234U/238U activity ratios (commonly 1.5-6) are present on both local and regional scales; however, ground water with 234U/238U activity ratios from 7 up to 8.06 is restricted largely to samples from Yucca Mountain. Data from ground water in the Tertiary volcanic and Quaternary alluvial aquifers at and adjacent to Yucca Mountain plot in 3 distinct fields of reciprocal U concentration versus 234U/238U activity ratio correlated to different geographic areas. Ground water to the west of Yucca Mountain has large U concentrations and moderate 234U/238U whereas ground water to the east in the Fortymile flow system has similar 234U/238U, but distinctly smaller U concentrations. Ground water beneath the central part of Yucca Mountain has intermediate U concentrations but distinctive 234U/238U activity ratios of about 7-8. Perched water from the lower part of the unsaturated zone at Yucca Mountain has similarly large values of 234U/238U. These U data imply that the Tertiary volcanic aquifer beneath the central part of Yucca Mountain is isolated from north-south regional flow. The similarity of 234U/238U in both saturated- and unsaturated-zone ground water at Yucca Mountain further indicates that saturated-zone ground water beneath Yucca Mountain is dominated by local recharge rather than regional flow. The distinctive 234U/238U signatures also provide a natural tracer of downgradient flow. Elevated 234U/238U in ground water from two water-supply wells east of Yucca Mountain are interpreted as the result of induced
Gondwe, Bibi Ruth Neuman; Merediz-Alonso, Gonzalo; Bauer-Gottwein, Peter
conceptualizations with uniform and heterogeneous distributions of hydraulic conductivities were used. The models demonstrated that Sian Ka’an’s wetlands are indeed groundwater-fed. The water quantities in the wetlands and the flooding dynamics are determined by the larger groundwater catchment. The overall water...... balance for the model domain showed that recharge constitutes 4400±700million m3/year. Of this, 4–12% exits as overland flow, and 88–96% exits as groundwater flow. Net groundwater outflow from the model domain to the north via the Holbox fracture zone appears as an important cross-basin transfer between...
Rojas, Rodrigo; Dassargues, Alain
The Pampa del Tamarugal Aquifer (PTA) is an important source of groundwater in northern Chile. Since the study area is situated in the Atacama Desert, the estimation of groundwater recharge based on conventional hydrological methods is subject to large uncertainties. To account for variations in the groundwater balance, caused by uncertainties in the average recharge rates, randomly generated recharge values with different levels of uncertainty are simulated using a groundwater flow model. Re...
Smith, Brennan; Schwartz, Stuart
Recharge estimation is an important and challenging element of groundwater management and resource sustainability. Many recharge estimation methods have been developed with varying data requirements, applicable to different spatial and temporal scales. The variability and inherent uncertainty in recharge estimation motivates the recommended use of multiple methods to estimate and bound regional recharge estimates. Despite the inherent limitations of using daily gauged streamflow, recession curve displacement methods provide a convenient first-order estimate as part of a multimethod hierarchical approach to estimate watershed-scale annual recharge. The implementation of recession curve displacement recharge estimation in the United States Geologic Survey (USGS) RORA program relies on the subjective, operator-specific selection of baseflow recession events to estimate a gauge-specific recession index. This paper presents a parametric algorithm that objectively automates this tedious, subjective process, parameterizing and automating the implementation of recession curve displacement. Results using the algorithm reproduce regional estimates of groundwater recharge from the USGS Appalachian Valley and Piedmont Regional Aquifer-System Analysis, with an average absolute error of less than 2%. The algorithm facilitates consistent, completely automated estimation of annual recharge that complements more rigorous data-intensive techniques for recharge estimation. © 2016, National Ground Water Association.
Preliminary simulation of chloride transport in the Equus Beds aquifer and simulated effects of well pumping and artificial recharge on groundwater flow and chloride transport near the city of Wichita, Kansas, 1990 through 2008
Klager, Brian J.; Kelly, Brian P.; Ziegler, Andrew C.
The Equus Beds aquifer in south-central Kansas is a primary water-supply source for the city of Wichita. Water-level declines because of groundwater pumping for municipal and irrigation needs as well as sporadic drought conditions have caused concern about the adequacy of the Equus Beds aquifer as a future water supply for Wichita. In March 2006, the city of Wichita began construction of the Equus Beds Aquifer Storage and Recovery project, a plan to artificially recharge the aquifer with excess water from the Little Arkansas River. Artificial recharge will raise groundwater levels, increase storage volume in the aquifer, and deter or slow down a plume of chloride brine approaching the Wichita well field from the Burrton, Kansas area caused by oil production activities in the 1930s. Another source of high chloride water to the aquifer is the Arkansas River. This study was prepared in cooperation with the cit