WorldWideScience

Sample records for artificial groundwater recharge

  1. Artificial recharge of groundwater: hydrogeology and engineering

    Science.gov (United States)

    Bouwer, Herman

    2002-02-01

    Artificial recharge of groundwater is achieved by putting surface water in basins, furrows, ditches, or other facilities where it infiltrates into the soil and moves downward to recharge aquifers. Artificial recharge is increasingly used for short- or long-term underground storage, where it has several advantages over surface storage, and in water reuse. Artificial recharge requires permeable surface soils. Where these are not available, trenches or shafts in the unsaturated zone can be used, or water can be directly injected into aquifers through wells. To design a system for artificial recharge of groundwater, infiltration rates of the soil must be determined and the unsaturated zone between land surface and the aquifer must be checked for adequate permeability and absence of polluted areas. The aquifer should be sufficiently transmissive to avoid excessive buildup of groundwater mounds. Knowledge of these conditions requires field investigations and, if no fatal flaws are detected, test basins to predict system performance. Water-quality issues must be evaluated, especially with respect to formation of clogging layers on basin bottoms or other infiltration surfaces, and to geochemical reactions in the aquifer. Clogging layers are managed by desilting or other pretreatment of the water, and by remedial techniques in the infiltration system, such as drying, scraping, disking, ripping, or other tillage. Recharge wells should be pumped periodically to backwash clogging layers. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s10040-001-0182-4.

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

    Science.gov (United States)

    Kimrey, J.O.

    1989-01-01

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

  3. ENGINEERING ECONOMIC ANALYSIS OF A PROGRAM FOR ARTIFICIAL GROUNDWATER RECHARGE.

    Science.gov (United States)

    Reichard, Eric G.; Bredehoeft, John D.

    1984-01-01

    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.

  4. Natural water purification and water management by artificial groundwater recharge

    OpenAIRE

    Balke, Klaus-Dieter; Zhu, Yan

    2008-01-01

    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...

  5. Radio-ecological aspects in artificial groundwater recharge

    International Nuclear Information System (INIS)

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

  6. Natural water purification and water management by artificial groundwater recharge

    Institute of Scientific and Technical Information of China (English)

    Klaus-Dieter BALKE; Yan ZHU

    2008-01-01

    Worldwide, several regions suffer from water scarcity and contamination. The infiltration and subsurface storage of rain and fiver water can reduce water stress. Artificial groundwater recharge, possibly combined with bank filtration, plant puri- fication 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 quanti-tative advantages. The contamination of infiltrated fiver water will be reduced by natural attenuation. Clay minerals, iron hy-droxide 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 fiver 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 fiver 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.

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

    Science.gov (United States)

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

    2013-07-01

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

  8. Identification of potential artificial groundwater recharge zones in Northwestern Saudi Arabia using GIS and Boolean logic

    Science.gov (United States)

    Zaidi, Faisal K.; Nazzal, Yousef; Ahmed, Izrar; Naeem, Muhammad; Jafri, Muhammad Kamran

    2015-11-01

    Identifying potential groundwater recharge zones is a pre-requisite for any artificial recharge project. The present study focuses on identifying the potential zones of Artificial Groundwater Recharge (AGR) in Northwestern Saudi Arabia. Parameters including slope, soil texture, vadose zone thickness, groundwater quality (TDS) and type of water bearing formation were integrated in a GIS environment using Boolean logic. The results showed that 17.90% of the total studied area is suitable for AGR. The identified zones were integrated with the land use/land cover map to avoid agricultural and inhabited lands which reduced the total potential area to 14.24%. Geomorphologically the wadi beds are the most suitable sites for recharge. On the basis of the potential AGR zones closeness to the available recharge water supply (rain water, desalinated sea water and treated waste water) the potential zones were classified as Category A (high priority) and Category B (low priority).

  9. Removal of Organic Pollutants in Municipal Wastewater for Artificial Groundwater Recharge

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In order to construct a demonstration artificial groundwater recharge system for wastewater reuse in China, three years of laboratory work has been conducted on advanced treatment technologies in combination with soil aquifer treatment of secondary effluent from sewage treatment plants. An effective and inexpensive process was selected, which uses DGB adsorption, PAC coagulation, sedimentation, sand filtration, ozone disinfection, and soil aquifer treatment. The effluent meets the recommended water quality criteria for groundwater recharge. Ozonation is effective for disinfection as well as for water quality improvement. Results showed that the total N in the SAT system remained constant thus the secondary effluent must have a low NH3-N concentration for groundwater recharge.

  10. An innovative artificial recharge system to enhance groundwater storage in basaltic terrain: example from Maharashtra, India

    Science.gov (United States)

    Bhusari, Vijay; Katpatal, Y. B.; Kundal, Pradeep

    2016-08-01

    The management of groundwater poses challenges in basaltic terrain as its availability is not uniform due to the absence of primary porosity. Indiscriminate excessive withdrawal from shallow as well as deep aquifers for meeting increased demand can be higher than natural recharge, causing imbalance in demand and supply and leading to a scarcity condition. An innovative artificial recharge system has been conceived and implemented to augment the groundwater sources at the villages of Saoli and Sastabad in Wardha district of Maharashtra, India. The scheme involves resectioning of a stream bed to achieve a reverse gradient, building a subsurface dam to arrest subsurface flow, and installation of recharge shafts to recharge the deeper aquifers. The paper focuses on analysis of hydrogeological parameters like porosity, specific yield and transmissivity, and on temporal groundwater status. Results indicate that after the construction of the artificial recharge system, a rise of 0.8-2.8 m was recorded in the pre- and post-monsoon groundwater levels in 12 dug wells in the study area; an increase in the yield was also noticed which solved the drinking water and irrigation problems. Spatial analysis was performed using a geographic information system to demarcate the area of influence of the recharge system due to increase in yields of the wells. The study demonstrates efficacy, technical viability and applicability of an innovative artificial recharge system constructed in an area of basaltic terrain prone to water scarcity.

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

    Science.gov (United States)

    Zhang, Xue; Zhao, Xuan

    2013-11-01

    A demonstration of artificial groundwater recharge with tertiary effluent was evaluated using a set of bioassays (acute toxicity to Daphnia, genotoxicity, estrogenic and antiestrogenic toxicity). Around 95 % genotoxicity and 53 % antiestrogenicity were removed from the feed water by ozonation, whereas significant reduction of acute toxicity to Daphnia magna was achieved during a 3 days vadose soil treatment. The toxicity was further removed to the same level as the local groundwater during a 20 days aquifer soil treatment. The pilot study has shown that ozonation and soil treatments can improve the quality of municipal wastewater treatment plant effluents for possible groundwater recharge purposes. PMID:24072260

  12. EFFECTS OF ARTIFICIAL RECHARGE ON GROUND-WATER QUALITY, LONG ISLAND, NEW YORK.

    Science.gov (United States)

    Schneider, Brian J.; Ku, Henry F.H.; Oaksford, Edward T.

    1986-01-01

    Artificial-recharge experiments were conducted at East Meadow in central Nassau County, Long Island, N. Y. , from October 1982 through January 1984, to evaluate the degree of ground-water mounding and chemical effects of artificially replenishing the ground-water system with tertiary-treated wastewater. Reclaimed water was provided by the Cedar Creek wastewater-treatment plant in Wantagh. Recharge with reclaimed water increased the concentration of sodium and chloride in ground water but lowered the concentrations of total nitrogen (nitrate plus nitrite) and some low-molecular-weight hydrocarbons. Reclaimed water was well within the New York State effluent standards for ground-water recharge. Specific-conductance measurements and Stiff diagrams of chemical analyses were used to help define the extent and shape of the plume formed by reclaimed water.

  13. Applicability of Artificial Recharge of Groundwater in the Yongding River Alluvial Fan in Beijing through Numerical Simulation

    Institute of Scientific and Technical Information of China (English)

    Qichen Hao; Jingli Shao; Yali Cui; Zhenhua Xie

    2014-01-01

    A groundwater transient flow model was developed to evaluate the applicability and ef-fectiveness of artificial recharge scenarios in the middle-upper part of the Yongding River alluvial fan in Beijing. These scenarios were designed by taking into account different types of recharge facilities and their infiltration rate with the Middle Route Project for South-to-North Water Transfer (MRP) as the recharge water source. The simulation results suggest that: (1) the maximum amount of artificial recharge water, for scenario I, would be 127.42×106 m3 with surface infiltration facilities;and would be 243.48×106 m3 for scenario II with surface infiltration and recharge wells under the constraint of the upper limit of groundwater;(2) with preferred pattern of recharge facilities, groundwater levels in both optimized recharge scenarios would not exceed the upper limit within the given recharge period;and (3) implementation of the recharge scenarios would efficiently increase the aquifer replenishment and the groundwater budget will change from-54.11×106 to 70.89×104 and 183.36×104 m3, respectively. In addi-tion, under these two scenarios groundwater level would rise up to 30 and 34 m, respectively, without increasing the amount of evaporation. The simulation results indicate that the proposed recharge sce-narios are practically feasible, and artificial recharge can also contribute to an efficient recovery of groundwater storage in Beijing.

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

    Science.gov (United States)

    Kupfersberger, Hans; Stadler, Hermann

    2010-05-01

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

  15. Using Decision Support System to Find Suitable Sites for Groundwater Artificial Recharge

    Science.gov (United States)

    Ghasemian, D.; Winter, C. L.; Kheirkhah Zarkesh, M. M.; Moradi, H. R.

    2014-12-01

    Some parts of Iran are considered as one of the driest regions of the world, where water is a limiting factor for lasting life therefore using seasonal floodwaters is very important in these arid regions. On the other hand, special attention has been paid to artificial groundwater recharge in these regions. Floodwater spreading on the permeable terrain is one of the flood control and utilization methods. Determination of appropriate site for water spreading is one of the most important stages of this project. Parameters considered in the selection of groundwater artificial recharge locations are diverse and complex. These factors consist of earth sciences (geology, geomorphology and soils), hydrology (runoff, sediment yield, infiltration and groundwater conditions) and socio-economic aspects (irrigated agriculture, flood damage mitigation, environment, job creation and so on). Hence, decision making depends on criteria of diverse nature. The goal of this study is defining a Decision Support System for floodwater site selection in Shahriary area. Four main criteria were selected in this research which are floodwater characters, infiltration, water applications and flood damage. In order to determine the weight of factors, Analytical Hierarchy Process was used. The results showed that soil texture and floodwater volume of infiltration are the most important factors. After providing output maps which had been defined in five scenarios, Kappa Index was used to evaluate the model. Based on the obtained results, the maps showed an acceptable agreement with control zones.

  16. A field study of advanced municipal wastewater treatment technology for artificial groundwater recharge

    Institute of Scientific and Technical Information of China (English)

    PI Yun-zheng; WANG Jian-long

    2006-01-01

    Field studies were conducted to investigate the advanced treatment of the municipal secondary effluent and a subsequent artificial groundwater recharge at Gaobeidian Wastewater Treatment Plant, Beijing. To improve the secondary effluent quality, the combined process of powdered activated carbon adsorption, flocculation and rapid sand filtration was applied, which could remove about 40% dissolved organic carbon (DOC) and 70% adsorbable organic halogens. The results of liquid size exclusion chromatography indicate that in the adsorption unit the removed organic fiaction was mainly low molecular weight compounds. The fiactions removed by the flocculation unit were polysaccharides and high molecular weight compounds. The retention of water in summer in the open recharge basins resulted in a growth of algae. Consequently, DOC increased in the polysaccharide and high molecular weight humic substances fiaction. The majority of the DOC removal during soil passage took place in the unsaturated area.A limited reduction of DOC was observed in the aquifer zone.

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

    Science.gov (United States)

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

    2010-05-01

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

  18. Is artificial recharge promoting microbial activity and biodegradation processes in groundwater systems?

    Science.gov (United States)

    Barba Ferrer, Carme; Folch, Albert; Gaju, Núria; Martínez-Alonso, Maira; Carrasquilla, Marc; Grau-Martínez, Alba; Sanchez-Vila, Xavier

    2016-04-01

    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.

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

    Science.gov (United States)

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

    2012-04-01

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

  20. Quantitative PCR Monitoring of Antibiotic Resistance Genes and Bacterial Pathogens in Three European Artificial Groundwater Recharge Systems▿ †

    OpenAIRE

    Böckelmann, Uta; Dörries, Hans-Henno; Ayuso-Gabella, M. Neus; Salgot de Marçay, Miquel; Tandoi, Valter; Levantesi, Caterina; Masciopinto, Costantino; Van Houtte, Emmanuel; Szewzyk, Ulrich; Wintgens, Thomas; Grohmann, Elisabeth

    2008-01-01

    Aquifer recharge presents advantages for integrated water management in the anthropic cycle, namely, advanced treatment of reclaimed water and additional dilution of pollutants due to mixing with natural groundwater. Nevertheless, this practice represents a health and environmental hazard because of the presence of pathogenic microorganisms and chemical contaminants. To assess the quality of water extracted from recharged aquifers, the groundwater recharge systems in Torreele, Belgium, Sabade...

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

    Science.gov (United States)

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

    2013-05-01

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

  2. Investigating the Energy-Water Usage Efficiency of the Reuse of Treated Municipal Wastewater for Artificial Groundwater Recharge.

    Science.gov (United States)

    Fournier, Eric D; Keller, Arturo A; Geyer, Roland; Frew, James

    2016-02-16

    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.

  3. Investigating the Energy-Water Usage Efficiency of the Reuse of Treated Municipal Wastewater for Artificial Groundwater Recharge.

    Science.gov (United States)

    Fournier, Eric D; Keller, Arturo A; Geyer, Roland; Frew, James

    2016-02-16

    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. PMID:26760055

  4. Flood water storage as a resource for agriculture and groundwater recharge: the empting of artificial leaking ponds

    Science.gov (United States)

    D'Oria, M.; Tanda, M.; Zanini, A.

    2008-12-01

    The large industrialization, intensive agriculture and the increasing population is giving rise to a lack of water resources. There is the need of capturing runoff for storing the water and using it during dry periods, but people now opposes to the realization of new dams. In Italy Public Authorities are showing a great interest in using ponds or small lakes located in the fluvial surroundings for storing water. The reservoirs can be filled up during flood events and can become, maintaining the water for a certain period, a resource for agriculture and a source of artificial recharge of groundwater. The hydraulic risks in the management of such small structures and the economic budget are lower than those involved in traditional reservoirs. In this work we propose a set of relationships with the aim of describing the interactions between the pond lakes and the beneath groundwater. This methodology allows to estimate the emptying time of the lake and its relative flow rate in a very fast way. It requires only a few parameters: the geometry of the problem, the initial lake and groundwater level and the hydraulic parameters of the aquifer and of the bottom of the lake. The solution of the problem was split in two cases: groundwater level always below the lakebed and groundwater level interacting with the lake level. It is possible to identify the two cases comparing the maximum flow rate drained from the aquifer (QS) to the one provided by the lake (QL). If QS is greater than QL the groundwater level maintains below the lakebed and vice versa. The two cases are well represented by simple relationships developed by the authors. These relationships were obtained using the results provided by a numerical model developed using MODFLOW 2000 with the LAKE3 package. Considering the first case, the relationship between the lake, groundwater level, the time and the leakance is represented by a straight line in a semi-logarithmic plane. In the case of the lake interconnected

  5. The effects of artificial recharge on groundwater levels and water quality in the west hydrogeologic unit of the Warren subbasin, San Bernardino County, California

    Science.gov (United States)

    Stamos, Christina L.; Martin, Peter; Everett, Rhett; Izbicki, John A.

    2013-01-01

    Between the late 1940s and 1994, groundwater levels in the Warren subbasin, California, declined by as much as 300 feet because pumping exceeded sparse natural recharge. In response, the local water district, Hi-Desert Water District, implemented an artificial-recharge program in early 1995 using imported water from the California State Water Project. Subsequently, the water table rose by as much as 250 feet; however, a study done by the U.S. Geological Survey found that the rising water table entrained high-nitrate septic effluent, which caused nitrate (as nitrogen) concentrations in some wells to increase to more than the U.S. Environmental Protection Agency maximum contaminant level of 10 milligrams per liter.. A new artificial-recharge site (site 3) was constructed in 2006 and this study, which started in 2004, was done to address concerns about the possible migration of nitrates in the unsaturated zone. The objectives of this study were to: (1) characterize the hydraulic, chemical, and microbiological properties of the unsaturated zone; (2) monitor changes in water levels and water quality in response to the artificial-recharge program at site 3; (3) determine if nitrates from septic effluent infiltrated through the unsaturated zone to the water table; (4) determine the potential for nitrates within the unsaturated zone to mobilize and contaminate the groundwater as the water table rises in response to artificial recharge; and (5) determine the presence and amount of dissolved organic carbon because of its potential to react with disinfection byproducts during the treatment of water for public use. Two monitoring sites were installed and instrumented with heat-dissipation probes, advanced tensiometers, suction-cup lysimeters, and wells so that the arrival and effects of recharging water from the State Water Project through the 250 to 425 foot-thick unsaturated zone and groundwater system could be closely observed. Monitoring site YVUZ-1 was located between two

  6. Evaluation of the potential for artificial ground-water recharge in eastern San Joaquin County, California; Phase 3

    Science.gov (United States)

    Hamlin, S.N.

    1987-01-01

    Infiltration tests were used to evaluate the potential of basin spreading surface water as a means of artificially recharging the aquifer system in eastern San Joaquin County, California. Two infiltration sites near Lockeford and Linden were selected on the basis of information collected during the first two phases of the study. Data from the infiltration tests indicate that the two sites are acceptable for recharge by the basin-spreading method. Infiltration rates ranged between 6.7 and 10.5 ft/day near Lockeford and between 2.6 and 11.2 ft/day near Linden. Interpretation of these data is limited by lack of information on the response of the saturated zone during testing and by the inherent difficulty in extrapolating the results of small-scale tests to larger long-term operations. Lithology is a major factor that controls infiltration rates at the test sites. The unsaturated zone is characterized by heterogeneous layers of coarse- and fine- grained materials. Clay layers of low hydraulic conductivity commonly form discontinuous lenses that may cause a transient perched water table to develop during recharge. Water level measurements from wells screened in the unsaturated zone indicate that the perched water table could reach the land surface after 2 and 5 months of recharge near Lockeford and Linden, respectively. These figures probably represent the minimum time necessary for saturation of the land. Another major factor that affects infiltration rates is the quality of the recharge water, particularly the suspended sediment content. The clogging action of suspended sediment may be minimized by: (1) pretreatment of recharge water in a settling pond, (2) adherence to a routine program of monitoring and maintenance, and (3) proper design of the recharge facility. Other factors that affect infiltration rates include basin excavation technique, basin shape, and maintenance procedures. Efficient operation of the recharge facility requires careful attention to the

  7. Groundwater recharge and agricultural contamination

    Science.gov (United States)

    Böhlke, J.K.

    2002-01-01

    Agriculture has had direct and indirect effects on the rates and compositions of groundwater recharge and aquifer biogeochemistry. Direct effects include dissolution and transport of excess quantities of fertilizers and associated materials and hydrologic alterations related to irrigation and drainage. Some indirect effects include changes in water-rock reactions in soils and aquifers caused by increased concentrations of dissolved oxidants, protons, and major ions. Agrilcultural 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 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.

  8. Artificial Recharge Coupled with Flood Mitigation in Jeju, Korea

    Science.gov (United States)

    Kim, Y.; Koo, M.; Lee, K.; Moon, D.; Barry, J. M.; Park, W.

    2010-12-01

    The primary goal of this study is to develop and apply the artificial recharge system at Han Stream in Jeju Island, Korea, for not only securing sustainable groundwater resources, but also mitigating severe floods occurred due to the global climate changes. Jeju-friendly Aquifer Recharge Technology (J-ART) in this study has been developed by capturing ephemeral stream water with no interference in the environments such as natural recharge or eco-system, storing the flood water in the reservoirs, recharging it through designed borehole after appropriate water treatment, and then making it to be used at down-gradient production wells. For optimal design of J-ART, we conducted injection tests at the monitoring well (MW5) as well as at the planned recharge site during drilling the recharge wells and performed a modeling with the data obtained. Based on the modeling results, the artificial recharge wells were developed with a design of 10-meter spacing between the wells and 35-40 meter depths, which has a capacity of more than 2,500,000 m3 of groundwater resources in a year. Characterizing groundwater flow from recharge area to discharge area should be achieved to assess the efficiency of J-ART. The resistivity logging employed to predict water flow in unsaturated zone during artificial recharge based on the inverse modeling and resistivity change patterns. Stable isotope studies of deuterium and oxygen-18 of surface waters and groundwaters were carried out to interpret mixing and flow in groundwaters impacted by artificial recharge. Transient models were developed to predict the effects of artificial recharge using the hydraulic properties of aquifers, groundwater levels, and meteorological data. Time series changes of water balance after artificial recharge were analyzed, and residence time of the recharged water was also predicted with a certain degree of uncertainty. Keywords: J-ART, Hydrogeological methods, Geophysical survey, Stable isotopes, Groundwater modeling

  9. Hydrogeological Methods for Assessing Feasibility of Artificial Recharge

    Science.gov (United States)

    Kim, Y.; Koo, M.; Lee, K.; Moon, D.; Barry, J. M.

    2009-12-01

    This study presents the hydrogeological methods to assess the feasibility of artificial recharge in Jeju Island, Korea for securing both sustainable groundwater resources and severe floods. Jeju-friendly Aquifer Recharge Technology (J-ART) in this study is developing by capturing ephemeral stream water with no interference in the environments such as natural recharge or eco-system, storing the flood water in the reservoirs, recharging it through designed borehole after appropriate water treatment, and then making it to be used at down-gradient production wells. Many hydrogeological methods, including physico-chemical surface water and groundwater monitoring, geophysical survey, stable isotope analysis, and groundwater modeling have been employed to predict and assess the artificially recharged surface waters flow and circulation between recharge area and discharge area. In the study of physico-chemical water monitoring survey, the analyses of surface water level and velocity, of water qualities including turbidity, and of suspended soil settling velocity were performed. For understanding subsurface hydrogeologic characteristics the injection test was executed and the results are 118-336 m2/day of transmissivity and 4,367-11,032 m3/day of the maximum intake water capacity. Characterizing groundwater flow from recharge area to discharge area should be achieved to assess the efficiency of J-ART. The resistivity logging was carried out to predict water flow in unsaturated zone during artificial recharge based on the inverse modeling and resistivity change patterns. Stable isotopes of deuterium and oxygen-18 of surface waters and groundwaters have been determined to interpret mixing and flow in groundwaters impacted by artificial recharge. A numerical model simulating groundwater flow and heat transport to assess feasibility of artificial recharge has been developed using the hydraulic properties of aquifers, groundwater levels, borehole temperatures, and meteorological

  10. Identifying Groundwater Recharge in Arid Regions

    Science.gov (United States)

    Thomas, B. F.; Famiglietti, J. S.

    2015-12-01

    Recharge epodicity in arid regions provides a method to estimate annual groundwater recharge given a relationship expressed as the recharge to precipitation ratio. Traditionally, in-situ observations are required to identify aquifer recharge events, while more advanced approaches such as the water-table fluctuation method or the episodic master recession method are necessary to delineate the recharge event. Our study uses the Gravity Recovery and Climate Experiment (GRACE) observations to estimate monthly changes in groundwater storage which are attributed to the combination of groundwater abstraction and episodic recharge in the arid southwestern United States. Our results illustrate the ability of remote sensing technologies to identify episodic groundwater recharge in arid regions which can be used within sustainable groundwater management frameworks to effectively manage groundwater resources.

  11. Availability of Surface Water of Wadi Rajil as a Source of Groundwater Artificial Recharge: A Case Study of Eastern Badia /Jordan

    Directory of Open Access Journals (Sweden)

    Rakad A. Ta'any

    2013-08-01

    Full Text Available Wadi Rajil catchment area is considered as one of the major wadis entering the Azraq Basin from the north. It is ungauged wadi and covers an area of about 3910km2. The annual average rainfall on Wadi Rajil catchment area is about 126.6mm. Heavy thunderstorms occur in April and May, causing significant floods covering the area. The flood waters are not utilized, and a small portion infiltrates into the ground, where the great portion of these waters remain over Qaa’ Azraqfew months before evaporation. Due to the absence of the hydrometric stream flow station, no data are available about surface water runoff in Wadi Rajil catchment area. Therefore, the first part of this study calculates the surface water potential of Wadi Rajil to be utilized for groundwater artificial recharge, applying the SCS curvilinear synthetic unit hydrograph method. The synthesis unit hydrograph of Wadi Rajil catchment is characterized by a peak value of 1146 m3/s (4047 cfs per one inch of rainfall excess. Flood hydrographs for 10,25,50, and 100 years return periods were derived and their peak flow are found to be 10,8,186,412, and 680 m3/s, respectively and the corresponding flood volumes are 0.95, 16.53, 36.89, and 61.5 MCM, respectively.Groundwater artificial recharge conditions are suitably prevailing in the most northern and central part of the catchment area, whereas, geological, Hydrogeological, and water quality characteristics of the floodwater encourage artificial replenishment of the exploited aquifer in the study area.

  12. Use of nuclear techniques in the study of artificial recharge of groundwater: case of groundwater table in Kairouan plane in Tunisia

    International Nuclear Information System (INIS)

    The groundwater table studied here is located in the plain of Kairouan and it is one of the main underground resources in the Centre of Tunisia. This region is characterized by a semi arid climate with high intensity of rain that causes flooding of Kairouan City. This study has two objectives namely: 1- To develop a technical process of this recharge. The experiment was realized at two sites. In each site were installed 3 neutron probe access tubes to the depth of the level of the ground water table.Successive measurements were taken in each tube in function of depth and time to follow up the hydrodynamics of the recharge of the water table. Neutron and gamma probes were used and compared with respect to measured water content.Each access tube for a fixed time give a water content profile which shows the dynamics of actual recharge and the previous recharge. this technique can help the developer to make decision concerning the recharge parameters and, particularly, the flow rate and the opportunity time to get the best recharge water efficiency. 2- To analyse the concentration of stable and radioactive isotopes in the water of the plain of kairouan. Samples were taken from the shallow and deep water table. The obtained results are helpful to specify the origin of the water. Geochemical analysis were also done to clear the spatial variability of the quality of water. To reach the fore mentioned objectives, a survey of wells using those resources was made. Samples were taken from all surveilled wells in this investigation. water samples were taken from the deep and shallow aquifers and to determine salt concentration as well as stable and radioactive element (O18, H2, C13, C14, H3). The results obtained from chemical analysis showed no clear spatial variability of water quality between the two aquifers. However the isotopic study gave two types of results: First: A significant difference between ages of the water coming from the shallow and the deep ground water

  13. The recharge process in alluvial strip aquifers in arid Namibia and implication for artificial recharge

    Science.gov (United States)

    Sarma, Diganta; Xu, Yongxin

    2016-10-01

    Alluvial strip aquifers associated with ephemeral rivers are important groundwater supply sources that sustain numerous settlements and ecological systems in arid Namibia. More than 70 % of the population in the nation's western and southern regions depend on alluvial aquifers associated with ephemeral rivers. Under natural conditions, recharge occurs through infiltration during flood events. Due to the characteristic spatial and temporal variability of rainfall in arid regions, recharge is irregular making the aquifers challenging to manage sustainably and they are often overexploited. This condition is likely to become more acute with increasing water demand and climate change, and artificial recharge has been projected as the apparent means of increasing reliability of supply. The article explores, through a case study and numerical simulation, the processes controlling infiltration, significance of surface water and groundwater losses, and possible artificial recharge options. It is concluded that recharge processes in arid alluvial aquifers differ significantly from those processes in subhumid systems and viability of artificial recharge requires assessment through an understanding of the natural recharge process and losses from the aquifer. It is also established that in arid-region catchments, infiltration through the streambed occurs at rates dependent on factors such as antecedent conditions, flow rate, flow duration, channel morphology, and sediment texture and composition. The study provides an important reference for sustainable management of alluvial aquifer systems in similar regions.

  14. Simulation of groundwater flow, effects of artificial recharge, and storage volume changes in the Equus Beds aquifer near the city of Wichita, Kansas well field, 1935–2008

    Science.gov (United States)

    Kelly, Brian P.; Pickett, Linda L.; Hansen, Cristi V.; Ziegler, Andrew C.

    2013-01-01

    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

  15. Simulation of Groundwater Mound Resulting from Proposed Artificial Recharge of Treated Sewage Effluent Case study – Gaza waste water treatment plant, Palestine

    OpenAIRE

    Aish, Adnan Mousa

    2010-01-01

    Mounding of the groundwater table beneath recharge sources is of concern as the raised water table approaches closely to near-surface facilities or features. The shape and height of the mound depend on several factors including the recharge rate, hydraulic conductivity and thickness of the aquifer. The objective of this paper is to evaluate the suitability of the study area for a rapid infiltration system of treated wastewater effluent without causing excessive mounding of the water table. A ...

  16. Echo Meadows Project Winter Artificial Recharge.

    Energy Technology Data Exchange (ETDEWEB)

    Ziari, Fred

    2002-12-19

    This report discusses the findings of the Echo Meadows Project (BPA Project 2001-015-00). The main purpose of this project is to artificially recharge an alluvial aquifer, WITH water from Umatilla River during the winter high flow period. In turn, this recharged aquifer will discharge an increased flow of cool groundwater back to the river, thereby improving Umatilla River water quality and temperature. A considerable side benefit is that the Umatilla River should improve as a habitat for migration, spanning, and rearing of anadromous and resident fish. The scope of this project is to provide critical baseline information about the Echo Meadows and the associated reach of the Umatilla River. Key elements of information that has been gathered include: (1) Annual and seasonal groundwater levels in the aquifer with an emphasis on the irrigation season, (2) Groundwater hydraulic properties, particularly hydraulic conductivity and specific yield, and (3) Groundwater and Umatilla River water quality including temperature, nutrients and other indicator parameters. One of the major purposes of this data gathering was to develop input to a groundwater model of the area. The purpose of the model is to estimate our ability to recharge this aquifer using water that is only available outside of the irrigation season (December through the end of February) and to estimate the timing of groundwater return flow back to the river. We have found through the data collection and modeling efforts that this reach of the river had historically returned as much as 45 cubic feet per second (cfs) of water to the Umatilla River during the summer and early fall. However, this return flow was reduced to as low as 10 cfs primarily due to reduced quantities of irrigation application, gain in irrigation efficiencies and increased groundwater pumping. Our modeling indicated that it is possible to restore these critical return flows using applied water outside of the irrigation season. We further

  17. Effect of redox conditions on the fate of emergin organic micropollutants during artificial recharge of groundwater: batch experiment

    OpenAIRE

    Barbieri, Manuela

    2011-01-01

    La recarrega artificial de les aigües subterrànies consisteix en infiltrar aigua als aqüífers per mitjà de les instal·lacions dissenyades per a tal fi i representa una eina important en la gestió dels recursos. A més de l’augment dels recursos d'aigües subterrànies, la recàrrega pot suposar una millora natural de la seva qualitat durant el seu pas pel subsòl. Els processos que tenen lloc en el sistema sòl-aqüífer (filtració, adsorció, reaccions de mescla , redox, biodegradació, et...

  18. Monitoring induced denitrification in an artificial aquifer recharge system.

    Science.gov (United States)

    Grau-Martinez, Alba; Torrentó, Clara; Folch, Albert; Domènech, Cristina; Otero, Neus; Soler, Albert

    2014-05-01

    As demands on groundwater increase, artificial recharge is becoming a common method for enhancing groundwater supply. The Llobregat River is a strategic water supply resource to the Barcelona metropolitan area (Catalonia, NE Spain). Aquifer overexploitation has leaded to both a decrease of groundwater level and seawater intrusion, with the consequent deterioration of water quality. In the middle section of the aquifer, in Sant Vicenç del Horts, decantation and infiltration ponds recharged by water from the Llobregat River (highly affected from wastewater treatment plant effluents), were installed in 2007, in the framework of the ENSAT Life+ project. At the bottom of the infiltration pond, a vegetal compost layer was installed to promote the growth of bacteria, to induce denitrification and to create favourable conditions for contaminant biodegradation. This layer consists on a mixture of compost, aquifer material, clay and iron oxide. Understanding the fate of contaminants, such as nitrate, during artificial aquifer recharge is required to evaluate the impact of artificial recharge in groundwater quality. In order to distinguish the source of nitrate and to evaluate the capability of the organic reactive layer to induce denitrification, a multi-isotopic approach coupled with hydrogeochemical data was performed. Groundwater samples, as well as river samples, were sampled during artificial and natural recharge periods. The isotopic analysis included: δ15N and δ18O of dissolved nitrate, δ34S and δ18O of dissolved sulphate, δ13C of dissolved inorganic carbon, and δ2H and δ18O of water. Dissolved nitrate isotopic composition (δ15NNO3 from +9 to +21 o and δ18ONO3 from +3 to +16 ) demonstrated that heterotrophic denitrification induced by the reactive layer was taking place during the artificial recharge periods. An approximation to the extent of nitrate attenuation was calculated, showing a range between 95 and 99% or between 35 and 45%, by using the extreme

  19. Characteristics of groundwater recharge on the North China Plain.

    Science.gov (United States)

    Tan, Xiu-Cui; Wu, Jing-Wei; Cai, Shu-Ying; Yang, Jin-Zhong

    2014-01-01

    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. PMID:24032445

  20. Artificial recharge of humic ground water.

    Science.gov (United States)

    Alborzfar, M; Villumsen, A; Grøn, C

    2001-01-01

    The purpose of this study was to investigate the efficiency of soil in removing natural organic matter from humic ground waters using artificial recharge. The study site, in western Denmark, was a 10,000 ml football field of which 2,000 m2 served as an infiltration field. The impact of the artificial recharge was studied by monitoring the water level and the quality of the underlying shallow aquifer. The humic ground water contained mainly humic adds with an organic carbon (OC) concentration of 100 to 200 mg C L(-1). A total of 5,000 mS of humic ground water were sprinkled onto the infiltration field at an average rate of 4.25 mm h(-1). This resulted in a rise in the water table of the shallow aquifer. The organic matter concentration of the water in the shallow aquifer, however, remained below 2.7 mg C L(-1). The organic matter concentration of the pore water in the unsaturated zone was measured at the end of the experiment. The organic matter concentration of the pore water decreased from 105 mg C L(-1) at 0.5 m to 20 mg C L(-1) at 2.5 m under the infiltration field indicating that the soil removed the organic matter from the humic ground water. From these results we conclude that artificial recharge is a possible method for humic ground water treatment.

  1. Quantifying Potential Groundwater Recharge In South Texas

    Science.gov (United States)

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

    2015-12-01

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

  2. Transient, spatially varied groundwater recharge modeling

    Science.gov (United States)

    Assefa, Kibreab Amare; Woodbury, Allan D.

    2013-08-01

    The objective of this work is to integrate field data and modeling tools in producing temporally and spatially varying groundwater recharge in a pilot watershed in North Okanagan, Canada. The recharge modeling is undertaken by using the Richards equation based finite element code (HYDRUS-1D), ArcGIS™, ROSETTA, in situ observations of soil temperature and soil moisture, and a long-term gridded climate data. The public version of HYDUS-1D and another version with detailed freezing and thawing module are first used to simulate soil temperature, snow pack, and soil moisture over a one year experimental period. Statistical analysis of the results show both versions of HYDRUS-1D reproduce observed variables to the same degree. After evaluating model performance using field data and ROSETTA derived soil hydraulic parameters, the HYDRUS-1D code is coupled with ArcGIS™ to produce spatially and temporally varying recharge maps throughout the Deep Creek watershed. Temporal and spatial analysis of 25 years daily recharge results at various representative points across the study watershed reveal significant temporal and spatial variations; average recharge estimated at 77.8 ± 50.8 mm/year. Previous studies in the Okanagan Basin used Hydrologic Evaluation of Landfill Performance without any attempt of model performance evaluation, notwithstanding its inherent limitations. Thus, climate change impact results from this previous study and similar others, such as Jyrkama and Sykes (2007), need to be interpreted with caution.

  3. Numerical approaches for approximating technical effectiveness of artificial recharge structures

    OpenAIRE

    Neumann, I.; Barker, J; MacDonald, D; Gale, I.

    2004-01-01

    This report describes various numerical approaches to quantify technical effectiveness of low-technology artificial recharge structures as seen commonly in rural environment and communities in semi-arid developing countries. The described methodologies enable benefits of artificial recharge facilities, i.e. their ability to replenish the aquifer, to be approximated. Technical effectiveness of recharge facilities is thereby evaluated on three scales: On a recharge basin scale, the rate of i...

  4. Numerical approaches for approximating technical effectivessness of artificial recharge structures

    OpenAIRE

    Neumann, I.; Barker, J; MacDonald, D; Gale, I.

    2004-01-01

    This report describes various numerical approaches to quantify technical effectiveness of low-technology artificial recharge structures as seen commonly in rural environment and communities in semi-arid developing countries. The described methodologies enable benefits of artificial recharge facilities, i.e. their ability to replenish the aquifer, to be approximated. Technical effectiveness of recharge facilities is thereby evaluated on three scales: On a recharge basin scale, the rate of i...

  5. Karst and artificial recharge: Theoretical and practical problems. A preliminary approach to artificial recharge assessment

    Science.gov (United States)

    Daher, Walid; Pistre, Séverin; Kneppers, Angeline; Bakalowicz, Michel; Najem, Wajdi

    2011-10-01

    SummaryManaged Aquifer Recharge (MAR) is an emerging sustainable technique that has already generated successful results and is expected to solve many water resource problems, especially in semi-arid and arid zones. It is of great interest for karst aquifers that currently supply 20-25% of the world's potable water, particularly in Mediterranean countries. However, the high heterogeneity in karst aquifers is too complex to be able to locate and describe them simply via field observations. Hence, as compared to projects in porous media, MAR is still marginal in karst aquifers. Accordingly, the present work presents a conceptual methodology for Aquifer Rechargeability Assessment in Karst - referred to as ARAK. The methodology was developed noting that artificial recharge in karst aquifers is considered an improbable challenge to solve since karst conduits may drain off recharge water without any significant storage, or recharge water may not be able to infiltrate. The aim of the ARAK method is to determine the ability of a given karst aquifer to be artificially recharged and managed, and the best sites for implementing artificial recharge from the surface. ARAK is based on multi-criteria indexation analysis modeled on karst vulnerability assessment methods. ARAK depends on four independent criteria, i.e. Epikarst, Rock, Infiltration and Karst. After dividing the karst domain into grids, these criteria are indexed using geological and topographic maps refined by field observations. ARAK applies a linear formula that computes the intrinsic rechargeability index based on the indexed map for every criterion, coupled with its attributed weighting rate. This index indicates the aptitude for recharging a given karst aquifer, as determined by studying its probability first on a regional scale for the whole karst aquifer, and then by characterizing the most favorable sites. Subsequently, for the selected sites, a technical and economic feasibility factor is applied, weighted

  6. An approach to identify urban groundwater recharge

    Directory of Open Access Journals (Sweden)

    E. Vázquez-Suñé

    2010-10-01

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

  7. An approach to identify urban groundwater recharge

    Directory of Open Access Journals (Sweden)

    E. Vázquez-Suñé

    2010-04-01

    Full Text Available Evaluating the proportion in which waters from different origins are mixed in a given water sample is relevant for many hydrogeological problems, such as quantifying total recharge, assessing groundwater pollution risks, or managing water resources. Our work is motivated by urban hydrogeology, where waters with different chemical signature can be identified (losses from water supply and sewage networks, infiltration from surface runoff and other water bodies, lateral aquifers inflows, .... The relative contribution of different sources to total recharge can be quantified by means of solute mass balances, but application is hindered by the large number of potential origins. Hence, the need to incorporate data from a large number of conservative species, the uncertainty in sources concentrations and measurement errors. We present a methodology to compute mixing ratios and end-members composition, which consists of (i Identification of potential recharge sources, (ii Selection of tracers, (iii Characterization of the hydrochemical composition of potential recharge sources and mixed water samples, and (iv Computation of mixing ratios and reevaluation of end-members. The analysis performed in a data set from samples of the Barcelona city aquifers suggests that the main contributors to total recharge are the water supply network losses (22%, the sewage network losses (30%, rainfall, concentrated in the non-urbanized areas (17%, from runoff infiltration (20%, and the Besòs River (11%. Regarding species, halogens (chloride, fluoride and bromide, sulfate, total nitrogen, and stable isotopes (18O2H, 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.

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

    Institute of Scientific and Technical Information of China (English)

    I.P. Senanayake; D.M.D.O.K. Dissanayake; B.B. Mayadunna; W.L. Weerasekera

    2016-01-01

    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 re-quirements 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 Ham-bantota. Influential thematic layers such as rainfall, lineament, slope, drainage, land use/land cover, li-thology, 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.

  9. Long-term improvement of agricultural vegetation by floodwater spreading in the Gareh Bygone Plain, Iran. In the pursuit of human security, is artificial recharge of groundwater more lucrative than selling oil?

    Science.gov (United States)

    Mesbah, Sayyed Hamid; Mohammadnia, Mehrdad; Kowsar, Sayyed Ahang

    2016-03-01

    In southern Iran's Gareh Bygone Plain, water-supply qanats in four mixed farming communities were desiccated by over-pumping of illegal dug wells throughout the area. Emergency situations developed, resulting in city-ward migration. Since 1983, 193 million m3 of water has been supplied to those communities by floodwater spreading (FWS) to facilitate spate irrigation of sandy rangeland (2,034 ha) and artificial recharge of groundwater (ARG), of which 76 % has recharged the aquifer. This resulted in a reverse migration of the population. The irrigated area in the 2010-2011 growing season increased 13.2 fold when compared to the pre-FWS period, and year-round forage for about 700 sheep has been provided since 1991. The ARG is a logical alternative to building large dams in Iran; 420,000 km2 of coarse-grained alluvium provides capacity to store 5,000 km3 of water, representing more than ten times the annual precipitation of the whole country. As the equivalent cost for building dams to accommodate that volume is estimated at US12.5 × 1012, the potential value of the alluvium may be realized. ARG on the recharge areas of 33,000 of the desiccated qanats eventually could rejuvenate them. As agricultural commodities absorb 19 % of the monetary value of Iran's imports, and ARG activities could supply the water to produce them, alluvium is even more valuable than oil, which provides foreign exchange. More importantly, ARG on 140,000 km2 of the alluvium could strengthen the capacity to adapt to droughts and reduce the number and impact of water-related emergency situations.

  10. Artificial Groundwater Recharge With Reclaimed Water Using EnhancedDirect Injection Well Recharge Process%组合式强化井灌工艺回灌再生水的中试研究

    Institute of Scientific and Technical Information of China (English)

    温保印; 张薛; 赵璇; 吴琳琳

    2011-01-01

    再生水地下回灌是缓解城市水资源短缺的有效途径之一.通过中试考察了污水厂二级出水经过反硝化生物滤池(DNBF)、超滤(UF)和臭氧(O3)预处理后,采用组合式强化井灌工艺(EnDir)回灌到地下含水层的工艺路线的可行性.在1年多的运行过程中,系统研究了回灌水水质特别是硝酸盐氮(NO3--N)浓度的变化情况.结果表明,该工艺对二级出水中DOC的去除率为59.7%,对UV254的去除率为61.0%,对硝酸盐氮的去除率为87.1%,对PO3-4-P的去除率为93.4%.氨氮主要在土壤处理单元被去除,去除率为45.9%.DNBF工艺能去除81.2%的硝酸盐氮,使其浓度降低至4.66 mg/L,同时不影响其他水质参数的变化.回灌水中SUVA值的变化规律显示,该系统对芳香族和脂肪族有机物的去除没有显著的选择性.%Groundwater recharge with reclaimed water is one of the effective ways to relieve urban water resource shortage. A pilot-scale experiment was carried out to investigate the feasibility of using the enhanced direct injection-well recharge (EnDir) process to recharge the secondary effluent from WWTP into the aquifer after the effluent was pretreated by denitrification biofilter (DNBF) , ultrafiltration (UF) and ozonation. During the operation for more than one year, the variation of the recharged water quality, especially of nitrate was studied. The results show that the total removal rates of DOC, UV254, NO3- - N and PO3-4 - P are 59.7% , 61.0% , 87. 1 % and 93.4% respectively. NH4+ - N of 45. 9% is removed by the soil treatment units. NO3- - N is reduced to 4. 66 mg/L (the removal rate of 81. 2% ) by the DNBF , without negative effects on the other parameters. Judging from the SUVA, this system has no significant selectivity in the removal of aromatic and aliphatic organic compounds.

  11. Simulated effects of ground-water withdrawals and artificial recharge on discharge to streams, springs, and riparian vegetation in the Sierra Vista Subwatershed of the Upper San Pedro Basin, southeastern Arizona

    Science.gov (United States)

    Leake, Stanley A.; Pool, Donald R.; Leenhouts, James M.

    2008-01-01

    In the context of ground-water resources, “capture” or “streamflow depletion” refers to withdrawal-induced changes in inflow to or outflow from an aquifer. These concepts are helpful in understanding the effects of long-term development of ground-water resources. For the Upper San Pedro Basin in Arizona, USA and Sonora, Mexico, a recently developed ground-water flow model is available to help quantify capture of water from the river and riparian system. A common method of analysis is to compute curves of capture and aquifer-storage change for a range of time at select points of interest. This study, however, presents results of a method to show spatial distributions of total change in inflow and outflow from withdrawal or injection for select times of interest. The mapped areal distributions show the effect of a single well in terms of the ratio of the change in boundary flow rate to rate of withdrawal or injection by the well. To the extent that the system responds linearly to ground-water withdrawal or injection, fractional responses in the mapped distributions can be used to quantify response for any withdrawal or injection rate. Capture distributions calculated using the Upper San Pedro model include response to (1) withdrawal in the lower basin-fill aquifer for times of 10 and 50 years following the initiation of pumping from predevelopment conditions and (2) artificial recharge to the water table in the area underlain by the lower basin-fill aquifer after 10 and 50 years. The mapped distributions show that response to withdrawals and injections is greatest near the river/riparian system. Presence of clay layers in the vertical interval between withdrawal locations and the river/riparian system, however, can delay the response.

  12. Using isotopes for design and monitoring of artificial recharge systems

    Science.gov (United States)

    Contributors: Hendriksson, N.; Kulongoski, J.T.; Massmann, G.; Newman, B.

    2013-01-01

    Over the past years, the IAEA has provided support to a number of Member States engaged in the implementation of hydrological projects dealing with the design and monitoring of artificial recharge ( A R ) systems, primarily situated in arid and semiarid regions. AR is defined as any engineered system designed to introduce water to, and store water in, underlying aquifers. Aquifer storage and recovery (ASR) is a specific type of AR used with the purpose of increasing groundwater resources. Different water management strategies have been tested under various geographical, hydrological and climatic regimes. However, the success of such schemes cannot easily be predicted, since many variables need to be taken into account in the early stages of every AR project.

  13. Theory of the generalized chloride mass balance method for recharge estimation in groundwater basins characterised by point and diffuse recharge

    Directory of Open Access Journals (Sweden)

    N. Somaratne

    2014-01-01

    Full Text Available 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, recharge estimation is unsuccessful using the conventional CMB method with, either unsaturated zone chloride or groundwater chloride. In this paper we describe a generalized CMB that can be applied to groundwater basins with point recharge. Results from this generalized CMB are shown to be comparable with long-term recharge estimates obtained using the watertable fluctuation method, groundwater flow modelling and Darcy flow calculations. The generalized CMB method provides an alternative, reliable long-term recharge estimation method for groundwater basins characterised by both point and diffuse recharge.

  14. Environmental tritium as a tool in groundwater recharge investigations

    International Nuclear Information System (INIS)

    This paper describes the use of environmental tritium to gain quantitative information on the rate of groundwater recharge to two different aquifers. Bomb derived tritium was used to determine actual groundwater recharge rates, first to a homogeneous unconfined aquifer and then to a heterogeneous unconfined aquifer. In the first study the aquifer of Cape Cod, Massachusetts, USA, was used. The aquifer is an unconfined phreatic lens within a homogeneous outwash deposit. In the second study a heterogeneous unconfined aquifer in southwest Michigan, USA, was used. This aquifer consists of poorly sorted outwash materials. In both studies the vertical depth of penetration of bomb derived tritium into the saturated zone at groundwater divides, was used in conjunction with porosity data to calculate the rate of groundwater recharge to the aquifers. The major assumption in this method of recharge rate determination is that the flow of groundwater at groundwater divides is essentially vertical and downward, approaching piston-type flow. Although the validity of this assumption has been questioned various groundwater transport models were applied to the tritium data in the two study areas. It was found that in these investigations hydrodynamic dispersion was not a significant process and that the flow of groundwater at groundwater divides could be considered, for the purposes of these investigations, to be piston-type. In both investigations the rate of groundwater recharge determined by the bomb tritium method was in close agreement with rates previously determined by conventional hydrologic techniques. Environmental tritium has been successfully used in these investigations to determine accurately the rate of groundwater recharge to homogeneous and heterogeneous unconfined aquifers. When employing the method outlined in this paper, it is necessary to identify the groundwater divides within the aquifer being studied and to sample groundwater for tritium analysis only from

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

    Science.gov (United States)

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

    2015-06-01

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

  16. [Effects of reclaimed water recharge on groundwater quality: a review].

    Science.gov (United States)

    Chen, Wei-Ping; Lü, Si-Dan; Wang, Mei-E; Jiao, Wen-Tao

    2013-05-01

    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.

  17. Pilot Test of Advanced Treatments Combination of Wastewater for Groundwater Recharge

    Institute of Scientific and Technical Information of China (English)

    成徐洲; 杨磊; 吴天宝; 甘一苹; 胡俊

    2002-01-01

    To solve the water shortage problem, an artificial groundwater recharge system will be constructed in Beijing for wastewater reuse as a demonstration and training center. Design and operating experience for the demonstration plant was gained through pilot tests of advanced treatment technologies with soil infiltration of well treated secondary effluent. The test results showed that the selected treatment technology meets the recommended water quality criteria for groundwater recharge and the gas chromatography-mass spectrometer (GC/MS) analysis results showed significantly improved water quality.

  18. Coupled modeling approach to assess climate change impacts on groundwater recharge and adaptation in arid areas

    Science.gov (United States)

    Hashemi, H.; Uvo, C. B.; Berndtsson, R.

    2015-10-01

    The effect of future climate scenarios on surface and groundwater resources was simulated using a modeling approach for an artificial recharge area in arid southern Iran. Future climate data for the periods of 2010-2030 and 2030-2050 were acquired from the Canadian Global Coupled Model (CGCM 3.1) for scenarios A1B, A2, and B1. These scenarios were adapted to the studied region using the delta-change method. A conceptual rainfall-runoff model (Qbox) was used to simulate runoff in a flash flood prone catchment. The model was calibrated and validated for the period 2002-2011 using daily discharge data. The projected climate variables were used to simulate future runoff. The rainfall-runoff model was then coupled to a calibrated groundwater flow and recharge model (MODFLOW) to simulate future recharge and groundwater hydraulic heads. As a result of the rainfall-runoff modeling, under the B1 scenario the number of floods is projected to slightly increase in the area. This in turn calls for proper management, as this is the only source of fresh water supply in the studied region. The results of the groundwater recharge modeling showed no significant difference between present and future recharge for all scenarios. Owing to that, four abstraction and recharge scenarios were assumed to simulate the groundwater level and recharge amount in the studied aquifer. The results showed that the abstraction scenarios have the most substantial effect on the groundwater level and the continuation of current pumping rate would lead to a groundwater decline by 18 m up to 2050.

  19. Study on Artificial Groundwater Recharge of Changxiao Water Source By Pumping Test in Jinan City%由抽水试验成果谈济南长孝水源地回灌补源

    Institute of Scientific and Technical Information of China (English)

    郑丽爽; 于大潞; 赵宇辉

    2015-01-01

    通过4.5万m3/d开采性抽水试验的观测表明长孝水源地具有较好的富水性及调蓄能力,开采潜力巨大。为保证长孝水源地的长期开采,应尽早采用外引内拦等工程措施,在孝里铺洼地地区实现地表水的回灌补源。这对提高城市供水保证率,恢复当地生态环境均具有十分深远的意义。%Through exploitation pumping test observation with the water amount of 45000 m3/d of No.1 Changxiao water source , it is showed that Changxiao water source has a good water enrichment and storage capacity and exploi -tation potentiality .In order to ensure long term extraction of Changxiao water source , some countermeasures should be adopted, such as outward water diversion and internal water stop .Thus, artificial groundwater recharge of sur-face water in Xiaolipu depression area can be realized .It will have a very significance in improving rate of water supply in city , and recoverying local ecological environment .

  20. Application of Isotope Techniques for the Estimation of Artificial Recharge

    International Nuclear Information System (INIS)

    Geochemical studies on the alluvial aquifer system near the Nakdong River were carried out for the basic investigation of the estimation of artificial recharge for the river bank filtration. In-situ data do not show any distinct difference between the pumping well and river. Most of waters belong Ca-HCO3 and Ca-SO4 types and show high Mn concentration. In the borehole installed with Multi-packer (MP) system, Na, Ca, Mg, HCO3 contents of the groundwater are increased with depth increasing. Cl and SO4 contents of the groundwater show the lowest values at the bottom level (18m depth) and Mn content is very high at the middle level (13.5m depth) of MP system. There is no distinct difference in the δ18O and D values and tritium content between MP, borehole and surface water samples. The sulfur isotope data indicate that the possible sulfur source is dissolution of sulfate mineral from sedimentary rock. Strontium isotope ratio shows a little differences between the pumping well and observation borehole samples. Nitrogen isotope data indicate that the nitrogen of water samples is originated from fertilizer or organic materials

  1. Theory of the generalized chloride mass balance method for recharge estimation in groundwater basins characterised by point and diffuse recharge

    OpenAIRE

    N. Somaratne; Smettem, K. R. J.

    2014-01-01

    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,...

  2. Identification of suitable locations for artificial groundwater recharge in a mining area of India by using remote sensing and GIS techniques

    OpenAIRE

    Tiwari, Ashwani Kumar; Lavy, Muriel; Amanzio, Gianpiero; De Maio, Marina

    2015-01-01

    Mining is one of the major activities causing water pollution and threating the quality and quantity of surface and groundwater resources in many parts of the world. Mining and related activities also damage the aquifer and decrease the water availability in the area. Groundwater may be considered as one of the most precious and basic needs for human existence and the survival of people providing the luxuries and comforts in addition to fulfilling the basic necessities of life. In India, more...

  3. Identifying Seasonal Groundwater Recharge Using Environmental Stable Isotopes

    Directory of Open Access Journals (Sweden)

    Hsin-Fu Yeh

    2014-09-01

    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.

  4. Groundwater chemical methods for recharge studies. The basic of recharge and discharge. Part 2

    International Nuclear Information System (INIS)

    Groundwater chemical methods for estimating recharge can provide useful information on groundwater sources and the location of major recharge areas. Two geochemical approaches that have been used successfully to quantify groundwater recharge rates are outlined. The first involves the use of mass balance and mixing cell models, mainly using conservative (non-reacting) dissolved species (3H, 2H, 18O, chloride). The methods range in complexity from simple calculations ( zero-dimensional chloride mass balance) to complex three-dimensional computer models. The second approach seeks to estimate the age or residence time of the groundwater by measuring compounds which are radioactive (14C) or whose input to the aquifer has been changing over time (chlorofluorocarbons). The methodology and some case studies are described. (authors)

  5. Removal of organic micropollutants in an artificial recharge system

    Science.gov (United States)

    Valhondo, C.; Nödler, K.; Köck-Schulmeyer, M.; Hernandez, M.; Licha, T.; Ayora, C.; Carrera, J.

    2012-04-01

    Emerging contaminants including pharmaceutically active compounds (PhACs), personal care products (PCPs) and pesticides are increasingly being identified in the environment. Emerging pollutants and their transformation products show low concentration in the environment (ng/L), but the effects of the mixtures and lifelong exposure to humans are currently unknown. Many of these contaminants are removed under aerobic conditions in water treatment plants. However, several pharmaceuticals and metabolites present in wastewater are not eliminated by conventional treatment processes. Several lab studies, however, show that the behaviour of many of these micropollutants is affected by the dominant redox conditions. However, data from field experiments are limited and sometimes contradictory. Artificial recharge is a widespread technology to increase the groundwater resources. In this study we propose a design to enhance the natural remediation potential of the aquifer with the installation of a reactive layer at the bottom of the infiltration pond. This layer is a mixture of compost, aquifer material, clay and iron oxide. This layer is intended to provide an extra amount of DOC to the recharge water and to promote biodegradation by means of the development of different redox zones along the travel path through the unsaturated zone and within the aquifer. Moreover, compost, clay and iron oxide of the layer are assumed to increase sorption surfaces for neutral, cationic and anionic compounds, respectively. The infiltration system is sited in Sant Vicenç dels Horts (Barcelona, Spain). It consists of a decantation pond, receiving raw water from the Llobregat River (highly affected from treatment plant effluents), and an infiltration pond (5600 m2). The infiltration rate is around 1 m3/m2/day. The system is equipped with a network of piezometers, suction cups and tensiometers. Infiltration periods have been performed before and after the installation of the reactive layer

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

    Science.gov (United States)

    Scanlon, Bridget R.; Keese, Kelley E.; Flint, Alan L.; Flint, Lorraine E.; Gaye, Cheikh B.; Edmunds, W. Michael; Simmers, Ian

    2006-10-01

    Global synthesis of the findings from 140 recharge study areas in semiarid and arid regions provides important information on recharge rates, controls, and processes, which are critical for sustainable water development. Water resource evaluation, dryland salinity assessment (Australia), and radioactive waste disposal (US) are among the primary goals of many of these recharge studies. The chloride mass balance (CMB) technique is widely used to estimate recharge. Average recharge rates estimated over large areas (40-374 000 km2) range from 0.2 to 35 mm year-1, representing 0.1-5% of long-term average annual precipitation. Extreme local variability in recharge, with rates up to 720 m year-1, results from focussed recharge beneath ephemeral streams and lakes and preferential flow mostly in fractured systems. System response to climate variability and land use/land cover (LU/LC) changes is archived in unsaturated zone tracer profiles and in groundwater level fluctuations. Inter-annual climate variability related to El Niño Southern Oscillation (ENSO) results in up to three times higher recharge in regions within the SW US during periods of frequent El Niños (1977-1998) relative to periods dominated by La Niñas (1941-1957). Enhanced recharge related to ENSO is also documented in Argentina. Climate variability at decadal to century scales recorded in chloride profiles in Africa results in recharge rates of 30 mm year-1 during the Sahel drought (1970-1986) to 150 mm year-1 during non-drought periods. Variations in climate at millennial scales in the SW US changed systems from recharge during the Pleistocene glacial period (10 000 years ago) to discharge during the Holocene semiarid period. LU/LC changes such as deforestation in Australia increased recharge up to about 2 orders of magnitude. Changes from natural grassland and shrublands to dryland (rain-fed) agriculture altered systems from discharge (evapotranspiration, ET) to recharge in the SW US. The impact of LU

  7. Climatic controls on diffuse groundwater recharge across Australia

    Directory of Open Access Journals (Sweden)

    O. V. Barron

    2012-05-01

    Full Text Available Reviews of field studies of groundwater recharge have attempted to investigate how climate characteristics control recharge, but due to a lack of data have not been able to draw any strong conclusions beyond that rainfall is the major determinant. This study has used numerical 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 types the total annual rainfall had a weaker correlation with recharge than the rainfall parameters reflecting rainfall intensity. In regions with winter-dominated rainfall, annual recharge under the same annual rainfall, soils and vegetation conditions is greater than in regions with summer-dominated rainfall. The relative importance of climate parameters other than rainfall is higher for recharge under annual vegetation, but overall is highest in the tropical climate type. Solar radiation and vapour pressure deficit show a greater relative importance than mean annual daily mean temperature. Climate parameters have lowest relative importance in the arid climate type (with cold winters and the temperate climate type. For 75% of all considered cases of soil, vegetation and climate types 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.

  8. GIS based site and structure selection model for groundwater recharge: a hydrogeomorphic approach.

    Science.gov (United States)

    Vijay, Ritesh; Sohony, R A

    2009-10-01

    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. PMID:21117424

  9. Determining Groundwater Recharge from Stream Flow with Seasonal Recession Method

    Directory of Open Access Journals (Sweden)

    Sumono

    2013-04-01

    Full Text Available Volume of groundwater recharge showed a picture of a watershed to determine the flow instability due to the physical characteristics of the watershed and precipitation. Many methods had been constructed to understand the dynamic movement of water discharge. One of them was the analysis of the stream hydrograph with Seasonal Recession Method. Information about groundwater recharge condition at several sub watershed in Krueng Peusangan Watershed was really needed in management of watershed for sustainable water resources. The study aimed to determine groundwater recharge from stream flow with seasonal recession method was conducted in Krueng Peusangan watershed, Aceh Province, Indonesia. The results showed that the trend pattern of the stream hydrograph could be explained using the exponential function where the dots lowest discharge that is the end of the recession (y than any period of time on stream hydrograph semi logarithmic (x. The pattern of results that occurred in the watershed of Krueng Peusangan: (A Krueng Seumpo had a trend for y = 9.2x-0.35, (B Simpang Jaya for y = 559.7x-0.5, (C Beukah village for y = 142x-0.32 , (D Sub watershed of Lut Tawar (Wih Nareh for y = 1.3x-0.12 and (E Sub watershed of Teupin Mane (Krueng Teumbo for y = 1.94x-0.42. It also showed that the location of A, B, C, E had a higher slope and a decreased recharge pattern compared to the location of D (sub watershed of Lut Tawar that tended to flat. The volume of groundwater recharge that occurred in a region (A and D increased while the other location was very volatile. Moreover, recharge instability occurred in Krueng Teumbo. Therefore, it needed a clear direction for land use and functions of forests, especially in the recharge area, in order to maintain the balance of the hydrological cycle, and the quantity of groundwater

  10. Groundwater suitability recharge zones modelling - A GIS application

    Science.gov (United States)

    Dabral, S.; Bhatt, B.; Joshi, J. P.; Sharma, N.

    2014-11-01

    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.

  11. Climatic controls on diffuse groundwater recharge across Australia

    Directory of Open Access Journals (Sweden)

    O. V. Barron

    2012-12-01

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

  12. Technologies and multi-barrier systems for sustainable groundwater recharge and irrigation

    OpenAIRE

    Besancon, Axelle

    2010-01-01

    Managed aquifer recharge (MAR) consists of artificially replenishing groundwater to facilitate reuse and/or the associated environmental benefits. Meanwhile, soil aquifer treatment (SAT) is a process of geo-purification designed and operated to improve the quality of the infiltrating water and is thus a type of MAR. SAT consists of a basin operating under rotation of drying and wetting periods. Often, SAT involves water of impaired quality applied onto soil and consequently ...

  13. Assimilating ambiguous observations to jointly estimate groundwater recharge and conductivity

    Science.gov (United States)

    Erdal, Daniel; Cirpka, Olaf A.

    2016-04-01

    In coupled modelling of catchments, the groundwater compartment can be an important water storage as well as having influence on both rivers and evapotranspirational fluxes. It is therefore important to parameterize the groundwater model as correctly as possible. Primarily important to regional groundwater flow is the spatially variable hydraulic conductivity. However, also the groundwater recharge, in a coupled system coming from the unsaturated zone but in a stand-alone groundwater model a boundary condition, is also of high importance. As with all subsurface systems, groundwater properties are difficult to observe in reality and their estimation is an ongoing topic in groundwater research and practice. Commonly, we have to rely on time series of groundwater head observations as base for any parameter estimation. Heads, however, have the drawback that they can be ambiguous and may not uniquely define the inverse problem, especially if both recharge and conductivity are seen as unknown. In the presented work we use a 2D virtual groundwater test case to investigate how the prior knowledge of recharge and conductivity influence their respective and joint estimation as spatially variable fields using head data. Using the Ensemble Kalman filter, it is shown that the joint estimation is possible if the prior knowledge is good enough. If the prior is erroneous the a-priori sampled fields cannot be corrected by the data. However, it is also shown that if the prior knowledge is directly wrong the estimated recharge field can resemble the true conductivity field, resulting in a model that meets the observations but has very poor predictive power. The study exemplifies the importance of prior knowledge in the joint estimation of parameters from ambiguous measurements.

  14. Groundwater recharge measurements in gravel sandy sediments with monolith lysimeter

    Science.gov (United States)

    Bracic Zeleznik, Branka; Souvent, Petra; Cencur Curk, Barbara; Zupanc, Vesna

    2013-04-01

    Ljubljana field aquifer is recharging through precipitation and the river Sava, which has the snow-rain flow regime. The sediments of the aquifer have high permeability and create fast flow as well as high regeneration of the dynamic reserves of the Ljubljana field groundwater resource. Groundwater recharge is vulnerable to climate change and it is very important for drinking water supply management. Water stored in the soil and less permeable layers is important for water availability under extreme weather conditions. Measurements of water percolation through the vadose zone provide important input for groundwater recharge assessment and estimation of contaminant migration from land surface to the groundwater. Knowledge of the processes governing groundwater recharge in the vadose zone is critical to understanding the overall hydrological cycle and quantifying the links between land uses and groundwater quantity and quality. To improve the knowledge on water balance for Ljubljana field aquifer we establish a lysimeter for measurements of processes in unsaturated zone in well field Kleče. The type of lysimeter is a scientific lysimeter designed to solve the water balance equation by measuring the mass of the lysimeter monolith as well as that of outflow tank with high accuracy and high temporal resolution. We evaluated short period data, however the chosen month demonstrates weather extremes of the local climate - relatively dry periods, followed by high precipitation amount. In time of high water usage of vegetation only subsequent substantial precipitation events directly results in water flow towards lower layers. At the same time, gravely layers of the deeper parts of the unsaturated zone have little or no capacity for water retention, and in the event that water line leaves top soil, water flow moves downwards fairly quickly. On one hand this confirms high recharge capacity of Ljubljana field aquifer from precipitation on green areas; on the other hand it

  15. Fluctuation of Groundwater Levels and Recharge Patterns in Northern Ghana

    Directory of Open Access Journals (Sweden)

    Alexandra Lutz

    2014-12-01

    Full Text Available Evaluating groundwater levels and recharge patterns is part of sustainably managing the water supply and predicting the possibility of water shortages, especially in light of climate change, extreme events (floods/droughts, increasing population and development. In the northern region of Ghana, groundwater is increasingly relied upon as a source of potable water for rural populations, but seasonal and inter-annual fluctuations of groundwater levels and recharge patterns are not always known. The fluctuation of groundwater levels on a seasonal basis shows that groundwater levels at all sites increase in response to seasonal precipitation. On an annual basis, all sites show an overall net decline of groundwater levels over the study period, which may be associated with below-average departures of precipitation during five of the seven study years. The variability of recharge patterns among five sites is attributed to the spatio-temporal variability of precipitation and hydrogeologic site uniqueness. The overarching potential benefit of this study is to facilitate closing knowledge gaps and contribute to a foundation for a more robust evaluation of groundwater resources in the area, especially as more data become available.

  16. Using Isotopes for Design and Monitoring of Artificial Recharge Systems

    International Nuclear Information System (INIS)

    Over the past years, the IAEA has provided support to a number of Member States engaged in the implementation of hydrological projects dealing with the design and monitoring of artificial recharge (AR) systems, primarily situated in arid and semiarid regions. AR is defined as any engineered system designed to introduce water to, and store water in, underlying aquifers. Aquifer storage and recovery (ASR) is a specific type of AR used with the purpose of increasing groundwater resources. Different water management strategies have been tested under various geographical, hydrological and climatic regimes. However, the success of such schemes cannot easily be predicted, since many variables need to be taken into account in the early stages of every AR project. As often occurs in the case of the assessment and management of groundwater and aquifers, information on hydrological behaviour and response to human-made actions is difficult to obtain and often very costly, especially if only conventional hydrological methods are used. Classical methods in AR and ASR are meant to provide information on changes in the volume and quality of the artificially introduced water to ensure its sustainability. Although the use of isotopes and geochemical tracers to plan and monitor AR and ASR has been limited, there is a growing number of publications reporting the successful application of tracers in the different phases of AR and ASR schemes. This publication discusses several theoretical aspects important to the understanding, planning and monitoring of AR and ASR schemes and presents a selected number of examples illustrating the usefulness of isotopes and other tracers. One section presents the list of available isotope tracers, indicating the type of information that can be obtained from each. The case studies presented in this publication illustrate the use of these tools in the different stages of AR and ASR schemes. The publication is expected to be of interest to hydrologists

  17. Application of GIS Based Tools for Groundwater Recharge and Evapotranspiration Estimation: Arc-Recharge and RIPGIS-NET

    Science.gov (United States)

    Ajami, H.; Hogan, J.; Maddock, T.; Meixner, T.

    2007-12-01

    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.

  18. Survey of land subsidence – case study: The land subsidence formation in artificial recharge ponds at South Hamadan Power Plant, northwest of Iran

    Indian Academy of Sciences (India)

    Ahmad Khorsandi Aghai

    2015-02-01

    The artificial recharge is a technique of aquifer conservation for land subsidence. But in this article, the phenomenon of land subsidence and the resulting cracks and fissures at the study area are formed in recharge ponds. This is a new phenomenon and in this research the geometrical properties of the fissures of recharge ponds are measured. The results reveal the existence of fine layers in the geology of the aquifer, which are displaced in the long run as the consequence of groundwater overdraft. At the site of the artificial recharge subject of this research, the difference between the quality of recharge water and the aquifer and their interaction have intensified the instability and the movement of the fine sediments. In addition, the neglect of hydraulic principles of the groundwater during the construction and operation of the recharge wells has resulted in turbulent and speed flows, intensified displacement of fine sediments and ultimately the localized subsidence at the site of the plan.

  19. 二级出水经地下水回灌后的梯级利用及安全评价%Step Utilization of Secondary Effluent Based on Artificial Groundwater Recharge and Safety Risk Assessment

    Institute of Scientific and Technical Information of China (English)

    魏亮亮; 赵庆良; 薛爽; 张金娜; 王丽娜; 王韶华; 钟卉元; 贾婷; 柳成才

    2012-01-01

    The transformation of pollutants during the reuse of the secondary effluent via soil aquifer treatment (SAT) in agricultural irrigation and industrial cooling water circulation was studied. Step u-tilization of secondary effluent was achieved by using artificial groundwater recharge as a " usage reduced, reused and recycled" water source. Compared to the secondary effluent without SAT, the reuse of the SAT effluent at 1.5 m depth could decrease the corrosion rate by 3/4 and scale formation by 55.1 % in the cooling systems. The structure of scale would become denser and less thick. In addition, the risk of chemical carcinogens within the SAT effluent at 1. 5 m depth in agricultural irrigation declined by 1 orders of magnitude compared with the secondary effluent without SAT.%在研究了污水厂二级出水经土壤含水层处理(SAT)以及在农业灌溉、工业冷却水等回用过程中污染物迁移转化的基础上,构建了以人工地下水回灌所得再生水作为回用水源,用于农业灌溉、工业冷却水的再生水梯级利用模式,实现了水资源的“减量化、再利用、再循环”.将SAT土壤柱1.5m处出水作为工业冷却水水源,可使冷却水系统的腐蚀速率较使用二级出水时低3/4,结垢量减少55.1%,且结垢物的结构致密、厚度变薄.将SAT土壤柱1.5m处出水作为农业灌溉水源时,可使化学致癌风险较单独使用二级出水时低1个数量级,躯体毒害物致癌风险明显降低.

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

    International Nuclear Information System (INIS)

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

  1. Fate of human viruses in groundwater recharge systems

    Energy Technology Data Exchange (ETDEWEB)

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

    1980-03-01

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

  2. Quantifying Groundwater Recharge During Dynamic Seasonality in Cold Climates

    Science.gov (United States)

    Pasha, E.; Rudolph, D. L.

    2015-12-01

    Estimating groundwater recharge in cold climates, during periods of dynamic seasonality such as winter and spring freshets is challenging due to subsurface heterogeneities and the complexity of vadose zone processes under partially frozen conditions. In order to obtain robust recharge estimates, numerical models simulating these complex processes need to be based on reliable parameter estimates and closely calibrated to field observations. This study focuses on quantifying recharge under an ephemeral stream that develops in the vicinity of a municipal well field during spring and winter freshets at a site in Southern Ontario. Temperature and moisture content profiles in the vadose zone were obtained during the 2015 spring melt at three different locations, using a variety of hydrogeological instruments. Temperature thermisters and Tid-Bit transducers were both installed at 15-30 cm spacings to the depth of the water table in order to compare and calibrate the results. Similarly, Time Domain Reflectometry probes were placed to the depth of the water table and the results were calibrated to daily moisture content readings taken with a Neutron Probe. Water table fluctuations were monitored and regular water samples were taken for analysis of geochemistry and isotope fractionation. This data provided the boundary conditions for the numerical model (Hydrus 1D) and allowed for its calibration and validation. Regions of rapid infiltration were observed at the site, as well as steep temperature gradients that could be used as a tracer for estimating recharge in cold climates. The geochemistry and isotope fractionation results provided support of surface water groundwater interaction within event based time periods predicted by the numerical models. Furthermore, the surface water samples were found to have high concentrations of microbial indicator species, and therefore the intense recharge phenomena observed at the site has significant implications to groundwater

  3. Groundwater recharge estimation and water resources assessment in a tropical crystalline basement aquifer

    OpenAIRE

    Nyagwambo, N.L.

    2006-01-01

    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...

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

    Directory of Open Access Journals (Sweden)

    Brian F. Thomas

    2016-03-01

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

  5. Groundwater recharge in Pleistocene sediments overlying basalt aquifers in the Palouse Basin, USA: modeling of distributed recharge potential and identification of water pathways

    OpenAIRE

    Dijksma, R.; Brooks, E.S.; Boll, J.

    2011-01-01

    Groundwater levels in basalt aquifers around the world have been declining for many years. Understanding water pathways is needed for solutions like artificial drainage. Water supply in the Palouse Basin, Washington and Idaho, USA, primarily relies on basalt aquifers. This study presents a combination of modeling and field observations to understand the spatial distribution of recharge pathways in the overlying Pleistocene sediments. A spatially distributed model was used to quantify potentia...

  6. An extended modeling approach to assess climate change impacts on groundwater recharge and adaptation in arid areas

    Directory of Open Access Journals (Sweden)

    H. Hashemi

    2014-10-01

    Full Text Available The impact of future climate scenarios on surface and groundwater resources was simulated using a modeling approach for an artificial recharge area in arid southern Iran. Future climate data for the periods of 2010–2030 and 2030–2050 were acquired from the Canadian Global Coupled Model (CGCM 3.1 for scenarios A1B, A2, and B1. These scenarios were adapted to the studied region using the delta-change method. The modified version of the HBV model (Qbox was used to simulate runoff in a flash flood prone catchment. The model was calibrated and validated for the period 2002–2011 using daily discharge data. The projected climate variables were used to simulate future runoff. The rainfall–runoff model was then coupled to a calibrated groundwater flow and recharge model (MODFLOW to simulate future recharge and groundwater hydraulic head. The results of the rainfall–runoff modeling showed that under the B1 scenario the number of floods might increase in the area. This in turn calls for a proper management, as this is the only source of fresh water supply in the studied region. The results of the groundwater recharge modeling showed no significant difference between present and future recharge for all scenarios. Owing to that, four abstraction and recharge scenarios were assumed to simulate the groundwater level and recharged water in the studied aquifer. The results showed that the abstraction scenarios have the most substantial effect on the groundwater level and the continuation of current pumping rate would lead to a groundwater decline by 18 m up to 2050.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-03-21

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

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

    OpenAIRE

    Bonsor, H. C.; A M. Macdonald

    2010-01-01

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

  9. Groundwater Recharge and Hydrogeochemical Evolution in Leizhou Peninsula, China

    Directory of Open Access Journals (Sweden)

    Yintao Lu

    2015-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    H. Bogena

    2005-01-01

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

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

    Science.gov (United States)

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

    2016-07-01

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

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

    Science.gov (United States)

    Tillman, Fred; Gangopadhyay, Subhrendu; Pruitt, Tom

    2016-01-01

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

  13. Transient,spatially-varied recharge for groundwater modeling

    Science.gov (United States)

    Assefa, Kibreab; Woodbury, Allan

    2013-04-01

    This study is aimed at producing spatially and temporally varying groundwater recharge for transient groundwater modeling in a pilot watershed in the North Okanagan, Canada. The recharge modeling is undertaken by using a Richard's equation based finite element code (HYDRUS-1D) [Simunek et al., 2002], ArcGISTM [ESRI, 2011], ROSETTA [Schaap et al., 2001], in situ observations of soil temperature and soil moisture and a long term gridded climate data [Nielsen et al., 2010]. The public version of HYDUS-1D [Simunek et al., 2002] and another beta version with a detailed freezing and thawing module [Hansson et al., 2004] are first used to simulate soil temperature, snow pack and soil moisture over a one year experimental period. Statistical analysis of the results show both versions of HYDRUS-1D reproduce observed variables to the same degree. Correlation coefficients for soil temperature simulation were estimated at 0.9 and 0.8, at depths of 10 cm and 50 cm respectively; and for soil moisture, 0.8 and 0.6 at 10 cm and 50 cm respectively. This and other standard measures of model performance (root mean square error and average error) showed a promising performance of the HYDRUS-1D code in our pilot watershed. After evaluating model performance using field data and ROSETTA derived soil hydraulic parameters, the HYDRUS-1D code is coupled with ArcGISTM to produce spatially and temporally varying recharge maps throughout the Deep Creek watershed. Temporal and spatial analysis of 25 years daily recharge results at various representative points across the study watershed reveal significant temporal and spatial variations; average recharge estimated at 77.8 ± 50.8mm /year. This significant variation over the years, caused by antecedent soil moisture condition and climatic condition, illustrates the common flaw of assigning a constant percentage of precipitation throughout the simulation period. Groundwater recharge modeling has previously been attempted in the Okanagan Basin

  14. Hydrologic effects of artificial-recharge experiments with reclaimed water at East Meadow, Long Island, New York

    Science.gov (United States)

    Schneider, B.J.; Ku, H.F.; Oaksford, E.T.

    1987-01-01

    Artificial recharge experiments were conducted at East Meadow, Long Island, New York, from October 1982 through January 1984 to evaluate the degree of groundwater mounding and the chemical effects of artificially replenishing the groundwater system with tertiary-treated wastewater. More than 800 million gallons of treated effluent was returned to the upper glacial aquifer through recharge basins and injection wells in the 15-month period. Reclaimed water was provided by the Cedar Creek advanced wastewater treatment facility in Wantagh, 6 miles away. The chlorinated effluent was pumped to the recharge facility, where it was fed to basins by gravity flow and to injection wells by pumps. Observations during the recharge tests indicate that the two most significant factors in limiting the rate of infiltration through the basin floor were the recharge test duration and quality of reclaimed water. Head buildup in the aquifer beneath the basins ranged from 4.3 to 6.7 ft, depending on the quantity and duration of water application. Head buildup near the injection wells within the aquifer ranged from 0.3 to 1.2 ft. Recharge basins provided a more effective means of moving large quantities of reclaimed water into the aquifer than injection wells. Results of 3-day and 176-day ponding tests in two basins indicate that reclaimed water is relatively unchanged chemically by percolation through the unsaturated zone because: (1) the sand and gravel of the upper glacial aquifer is unreactive, (2) the water moves to the water table rapidly, and (3) the water is highly treated before recharge. The quality of water in the aquifer zones affected by recharge improved, on the whole. Groundwater concentrations of nitrate nitrogen and several low molecular weight hydrocarbons, decreased to well within drinking water standards as a direct result of recharge. Sodium and chloride concentrations increased above background levels as a result of recharge but remained well within drinking water

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

    Science.gov (United States)

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

    2014-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Savard, C.S.

    1998-10-01

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

  17. Investigation of discharge-area groundwaters for recharge source characterization on different scales: the case of Jinan in northern China

    Science.gov (United States)

    Wang, Jiale; Jin, Menggui; Lu, Guoping; Zhang, Dele; Kang, Fengxin; Jia, Baojie

    2016-05-01

    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.

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

    Science.gov (United States)

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

    2016-04-01

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

  19. Nitrate reduction during ground-water recharge, Southern High Plains, Texas

    Science.gov (United States)

    Fryar, Alan E.; Macko, Stephen A.; Mullican, William F., III; Romanak, Katherine D.; Bennett, Philip C.

    2000-01-01

    In arid and semi-arid environments, artificial recharge or reuse of wastewater may be desirable for water conservation, but NO 3- contamination of underlying aquifers can result. On the semi-arid Southern High Plains (USA), industrial wastewater, sewage, and feedlot runoff have been retained in dozens of playas, depressions that focus recharge to the regionally important High Plains (Ogallala) aquifer. Analyses of ground water, playa-basin core extracts, and soil gas in an 860-km 2 area of Texas suggest that reduction during recharge limits NO 3- loading to ground water. Tritium and Cl - concentrations in ground water corroborate prior findings of focused recharge through playas and ditches. Typical δ15N values in ground water (>12.5‰) and correlations between δ15N and ln CNO -3-N suggest denitrification, but O 2 concentrations ≥3.24 mg l -1 indicate that NO 3- reduction in ground water is unlikely. The presence of denitrifying and NO 3--respiring bacteria in cores, typical soil-gas δ15N values water can still exceed drinking-water standards, as observed in the vicinity of one playa that received wastewater. Therefore, continued ground-water monitoring in the vicinity of other such basins is warranted.

  20. Groundwater recharge mechanisms inferred from isoscapes in a complex tropical mountainous region

    Science.gov (United States)

    Sánchez-Murillo, Ricardo; Birkel, Christian

    2016-05-01

    Stable isotope variations and groundwater recharge mechanisms remain poorly understood across the tropics, particularly in Central America. Here stable isotopes (δ18O and δ2H) in groundwater, surface water, and rainfall are used to produce high-resolution (100 m2 grid) isoscapes for Costa Rica, from which an isotope ratio of precipitation to groundwater (P/GW) is estimated to elucidate the dominant groundwater recharge processes. Spatially, groundwater and surface water isotope ratios depict the strong orographic separation into the Caribbean and Pacific slopes induced by moisture transport directly from the Caribbean Sea and the eastern tropical Pacific Ocean. P/GW isotope ratios reveal that groundwater recharge is biased toward intensive and more depleted monthly rainfall across the Pacific slope with clear evidence of secondary evaporation indicating slower soil matrix recharge processes. On the other hand, P/GW isotope ratios indicate a weak influence of secondary evaporation across the Caribbean slope suggesting rapid recharge via preferential flow paths.

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

    Energy Technology Data Exchange (ETDEWEB)

    Cobos, G. de los

    2009-07-01

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

  2. The preliminary study of groundwater recharge system in Kathmandu Valley, Nepal

    International Nuclear Information System (INIS)

    This study aims to identify the groundwater recharge systems of Kathmandu Valley using isotopic compositions of water (δ18O and δ2H) along with other hydrochemistry data. The preliminary study consisted of 15 deep groundwater and 5 shallow groundwater samples that were collected from northern and central part of the valley. Three types of the deep groundwater isotope compositions were observed while δ18O is plotted against δ2H. The results indicate that the deep groundwater has two main aquifers: north part and central part aquifers. In addition, the oxygen isotopic values of all samples when plotted against chloride indicate that deep groundwater is not being recharged by the shallow groundwater of the sampled area. It was also observed that the third type of groundwater is formed by the mixing of first and second types of groundwater. The next study will be focused on detailed investigation in finding source and recharge of this groundwater. (author)

  3. Treatment of Organic Compounds in Reclaimed Wastewater for Groundwater Recharge

    Institute of Scientific and Technical Information of China (English)

    皮运正; 胡俊; 云桂春

    2004-01-01

    To study water quality problems associated with groundwater recharge,a tertiary treatment process,consisting of coagulation,sand filtration,and granular activated carbon (GAC) adsorption,was used in combination with a simulated soil aquifer treatment.The process significantly improved secondary effluent quality.GAC adsorption reduced organic substances expressed by UV-254,dissolved organic carbon as well as partially adsorbable organic halogens.The results of the Ames test show that the secondary effluent contains a high concentration of mutagens.GAC filtration removed adsorbable organic bromine slightly whereas GAC adsorption removed mutagens effectively.The simulated soil aquifer treatment was able to further reduce UV-254,dissolved organic carbon,and adsorbable organic halogens through biodegradation.Adsorbable organic bromine levels were also reduced by the soil aquifer treatment process.The given reclamation technology used for groundwater recharge is of benefit to the removal of dissolved organic carbon,UV-254,adsorbable organic halogens,and mutagenicity.

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

    Science.gov (United States)

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

    2016-04-01

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

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

    International Nuclear Information System (INIS)

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

  6. Hydrological functions of sinkholes and characteristics of point recharge in groundwater basins

    OpenAIRE

    N. Somaratne; K. Smettem; Lawson, J; Nguyen, K.; J. Frizenschaf

    2013-01-01

    Karstic limestone aquifers are hydrologically and hydrochemically extremely heterogeneous and point source recharge via sinkholes and fissures is a common feature. We studied three groundwater systems in karstic settings dominated by point source recharge in order to assess the relative contributions to total recharge from point sources using chloride and δ18O relations. Preferential groundwater flows were observed through an inter-connected network of highly conductive zone...

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

    Directory of Open Access Journals (Sweden)

    A. P. Atkinson

    2014-06-01

    14C ages are between 100 and 10 000 years. 3H activities are negligible in most of the groundwater and groundwater electrical conductivity in individual areas remains constant over the period of study. Although diffuse local recharge is evident, the depth to which it penetrates is limited to the upper 10 m of the aquifer. Rather, groundwater in the Gellibrand Valley predominantly originates from the regional recharge zone, the Barongarook High, and acts as a regional discharge zone where upward head gradients are maintained annually, limiting local recharge. Additionally, the Gellibrand River does not recharge the surrounding groundwater and has limited bank storage. 14C ages and Cl concentrations are well correlated and Cl concentrations may be used to provide a first-order estimate of groundwater residence times. Progressively lower chloride concentrations from 10 000 years BP to the present day are interpreted to indicate an increase in recharge rates on the Barongarook High.

  8. Effects of Soil and Water Conservation Measures on Groundwater Levels and Recharge

    Directory of Open Access Journals (Sweden)

    Hong Wang

    2014-12-01

    Full Text Available 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 flow field all showed that MODFLOW could be applied to study the impact of SWC measures on groundwater. Meanwhile, the results showed the recharge rate (α and specific yield of the three soil layers (Sy1, Sy2 and Sy3 were the most sensitive parameters to the change in the underlying surface. Then, the impacts of the SWC measures’ construction and destruction on the groundwater regime were studied. The results indicated the measures could strengthen groundwater recharge. The amounts of groundwater recharge, runoff and level were on the order of straw mulching > grassland > bare slope. When the underlying surface was converted from grass and mulching to bare slope, the recharge decreased by 42.2% and 39.1%. It was concluded that SWC measure construction would increase groundwater recharge and the measure destruction would decrease recharge.

  9. Groundwater Level Predictions Using Artificial Neural Networks

    Institute of Scientific and Technical Information of China (English)

    毛晓敏; 尚松浩; 刘翔

    2002-01-01

    The prediction of groundwater level is important for the use and management of groundwater resources. In this paper, the artificial neural networks (ANN) were used to predict groundwater level in the Dawu Aquifer of Zibo in Eastern China. The first step was an auto-correlation analysis of the groundwater level which showed that the monthly groundwater level was time dependent. An auto-regression type ANN (ARANN) model and a regression-auto-regression type ANN (RARANN) model using back-propagation algorithm were then used to predict the groundwater level. Monthly data from June 1988 to May 1998 was used for the network training and testing. The results show that the RARANN model is more reliable than the ARANN model, especially in the testing period, which indicates that the RARANN model can describe the relationship between the groundwater fluctuation and main factors that currently influence the groundwater level. The results suggest that the model is suitable for predicting groundwater level fluctuations in this area for similar conditions in the future.

  10. Hydrological functions of sinkholes and characteristics of point recharge in groundwater basins

    Directory of Open Access Journals (Sweden)

    N. Somaratne

    2013-09-01

    Full Text Available Karstic limestone aquifers are hydrologically and hydrochemically extremely heterogeneous and point source recharge via sinkholes and fissures is a common feature. We studied three groundwater systems in karstic settings dominated by point source recharge in order to assess the relative contributions to total recharge from point sources using chloride and δ18O relations. Preferential groundwater flows were observed through an inter-connected network of highly conductive zones with groundwater mixing along flow paths. Measurements of salinity and chloride indicated that fresh water pockets exist at point recharge locations. A measurable fresh water plume develops only when a large quantity of surface water enters the aquifer as a point recharge source. The difference in chloride concentrations in diffuse and point recharge zones decreases as aquifer saturated thickness increases and the plumes become diluted through mixing. The chloride concentration in point recharge fluxes crossing the watertable plane can remain at or near surface runoff chloride concentrations, rather than in equilibrium with groundwater chloride. In such circumstances the conventional chloride mass balance method that assumes equilibrium of recharge water chloride with groundwater requires modification to include both point and diffuse recharge mechanisms.

  11. Present-day groundwater recharge estimation in parts of the Indian Sub-Continent

    Science.gov (United States)

    Bhanja, S. N.; Mukherjee, A.; Wada, Y.; Scanlon, B. R.; Taylor, R. G.; Rodell, M.; Malakar, P.

    2015-12-01

    Large part of global population has been dependent on groundwater as a source of fresh water. The demand would further increase with increasing population and stress associated with climate change. We tried to provide regional-scale groundwater recharge estimates in a large part of Indian Sub-Continent. A combination of ground-based, satellite-based and numerical model simulated recharge estimates were presented in the densely populated region. Three different methods: an intense network of observational wells (n>13,000 wells), a satellite (TRMM) and global land-surface model (CLM) outputs, and a global-scale hydrological model (PCR GLOBWB) were employed to calculate recharge estimates. Groundwater recharge values exhibit large spatial variations over the entire region on the basis of aquifer hydrogeology, precipitation and groundwater withdrawal patterns. Groundwater recharge estimates from all three estimation techniques were found to be higher (>300 mm/year) in fertile planes of Indus-Ganges-Brahmaputra (IGB) river basins. A combination of favorable hydrogeologic conditions (porosity, permeability etc.), comparatively higher rates of precipitation, and return flow from rapidly withdrawn irrigation water might influence occurrence of high recharge rates. However, central and southern study area experiences lower recharge rates (recharge estimates show good matches in some of the areas. Recharge estimates indicate dynamic nature of groundwater recharge as a function of precipitation, land use pattern, and hydrogeologic parameters. On a first hand basis, the estimates will help policy makers to understand groundwater recharge process over the densely populated region and finally would facilitate to implement sustainable policy for securing water security.

  12. Tracing groundwater recharge in the San Luis Valley, Colorado: Groundwater contamination susceptibility in an agricultural watershed

    Science.gov (United States)

    Patel, Tanya; Hindshaw, Ruth; Singer, Michael

    2015-04-01

    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

  13. Entropy based groundwater monitoring network design considering spatial distribution of annual recharge

    Science.gov (United States)

    Leach, James M.; Coulibaly, Paulin; Guo, Yiping

    2016-10-01

    This study explores the inclusion of a groundwater recharge based design objective and the impact it has on the design of optimum groundwater monitoring networks. The study was conducted in the Hamilton, Halton, and Credit Valley regions of Ontario, Canada, in which the existing Ontario Provincial Groundwater Monitoring Network was augmented with additional monitoring wells. The Dual Entropy-Multiobjective Optimization (DEMO) model was used in these analyses. The value of using this design objective is rooted in the information contained within the estimated recharge. Recharge requires knowledge of climate, geomorphology, and geology of the area, thus using this objective function can help account for these physical characteristics. Two sources of groundwater recharge data were examined and compared, the first was calculated using the Precipitation-Runoff Modeling System (PRMS), and the second was an aggregation of recharge found using both the PRMS and Hydrological Simulation Program-Fortran (HSP-F). The entropy functions are used to identify optimal trade-offs between the maximum information content and the minimum shared information between the monitoring wells. The recharge objective will help to quantify hydrological characteristics of the vadose zone, and thus provide more information to the optimization algorithm. Results show that by including recharge as a design objective, the spatial coverage of the monitoring network can be improved. The study also highlights the flexibility of DEMO and its ability to incorporate additional design objectives such as the groundwater recharge.

  14. Seasonality of Groundwater Recharge in the Basin and Range Province, Western North America

    Science.gov (United States)

    Neff, K. L.; Meixner, T.; Ajami, H.; De La Cruz, L.

    2015-12-01

    For water-scarce communities in the western U.S., it is critical to understand groundwater recharge regimes and how those regimes might shift in the face of climate change and impact groundwater resources. Watersheds in the Basin and Range Geological Province are characterized by a variable precipitation regime of wet winters and variable summer precipitation. The relative contributions to groundwater recharge by summer and winter precipitation vary throughout the province, with winter precipitation recharge dominant in the northern parts of the region, and recharge from summer monsoonal precipitation playing a more significant role in the south, where the North American Monsoon (NAM) extends its influence. Stable water isotope data of groundwater and seasonal precipitation from sites in Sonora, Mexico and the U.S. states of California, Nevada, Utah, Arizona, Colorado, New Mexico, and Texas were examined to estimate and compare groundwater recharge seasonality throughout the region. Contributions of winter precipitation to annual recharge vary from 69% ± 41% in the southernmost Río San Miguel Basin in Sonora, Mexico, to 100% ± 36% in the westernmost Mojave Desert of California. The Normalized Seasonal Wetness Index (NSWI), a simple water budget method for estimating recharge seasonality from climatic data, was shown to approximate recharge seasonality well in several winter precipitation-dominated systems, but less well in basins with significant summer precipitation.

  15. Downstream of downtown: urban wastewater as groundwater recharge

    Science.gov (United States)

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

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

  16. Conceptualisation of groundwater recharge from the Wairau River, New Zealand

    Science.gov (United States)

    Wilson, Scott; Wöhling, Thomas; Davidson, Peter

    2016-04-01

    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

  17. Precision Gravity Monitoring of Artificial Recharge at Little Cottonwood Canyon, Wasatch Front, Utah

    Science.gov (United States)

    Johnson, B. S.; Gettings, P.; Chapman, D. S.

    2008-12-01

    Repeated high-precision (± 5 μGal) gravity surveys are used to monitor artificial groundwater recharge at the Little Cottonwood Water Treatment Plant (LCWTP) in the southern portion of the Salt Lake Valley, UT. The gravity survey network consists of 30 sites arranged to capture the expected horizontal migration (> 500 meters/yr) of the infiltrated water. An additional 4 stations are arranged 1500 meters from the LCWTP infiltration sites for regional and environmental background control. Prior to starting recharge operations, a set of five background surveys were made between spring 2006 and summer 2007. Background (natural/environmental) variability is reliably estimated at 20 μGals. Infiltration commenced in mid-September 2007 and bimonthly gravity surveys were conducted until July 2008. A peak gravity change of 100 μGals was observed at the end of infiltration. The campaigns following cessation of infiltration showed a decreasing gravity anomaly indicating a dispersion of the ground water mound produced by the infiltration. The final gravity results from July of 2008 showed a 70 μGal decrease from the peak gravity value. Observations suggest the subsurface water flowed to the west of the LCWTP; however the control stations at the western most extent of the survey area show no increase in gravity. The gravity observations are comparable to a previous study conducted in the Weber River delta, which showed that the gravity decay over 3-5 months can be used to determine the bulk hydraulic conductivity of the area.

  18. Impacts of thickening unsaturated zone on groundwater recharge in the North China Plain

    Science.gov (United States)

    Cao, Guoliang; Scanlon, Bridget R.; Han, Dongmei; Zheng, Chunmiao

    2016-06-01

    Unsustainable groundwater development shown by rapid groundwater depletion in the North China Plain (NCP) underscores the need to quantify spatiotemporal variability in groundwater recharge for improved management of the resource. The objective of this study was to assess spatiotemporal variability in recharge in response to thickening of the unsaturated zone in the NCP. Recharge was estimated by linking a soil water balance (SWB) model, on the basis of monthly meteorological data, irrigation applications, and soil moisture monitoring data (1993-2008), to the water table using a deep unsaturated zone flow model. The dynamic bottom boundary (water table) position was provided by the saturated zone flow component, which simulates regional pumping. The model results clearly indicate the effects of unsaturated zone thickening on both temporal distribution and magnitude of recharge: smoothing temporal variability in recharge, and increasing unsaturated storage and lag time between percolation and recharge. The thickening unsaturated zone can result in average recharge reduction of up to ∼70% in loam soils with water table declines ⩾30 m. Declining groundwater levels with irrigation sourced by groundwater converts percolation to unsaturated zone storage, averaging 14 mm equivalent water depth per year in mostly loam soil over the study period, accounting for ∼30% of the saturated groundwater storage depletion. This study demonstrates that, in thickening unsaturated zones, modeling approaches that directly equate deep drainage with recharge will overestimate the amount and underestimate the time lag between percolation and recharge, emphasizing the importance of more realistic simulation of the continuity of unsaturated and saturated storage to provide more reliable estimates of spatiotemporal variability in recharge.

  19. Estimated mean annual natural ground-water recharge in the conterminous United States

    Data.gov (United States)

    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...

  20. Hydrogeology, Kennedy-Jenks groundwater recharge report, Published in 2004, Washoe County.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Hydrogeology dataset, was produced all or in part from Published Reports/Deeds information as of 2004. It is described as 'Kennedy-Jenks groundwater recharge...

  1. Ground-Water Recharge in the Arid and Semiarid Southwestern United States - Climatic and Geologic Framework

    Science.gov (United States)

    Stonestrom, David A.; Harrill, James R.

    2007-01-01

    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

  2. Estimation of Spatially and Temporally Varied Groundwater Recharge from Precipitation Using a Systematic and Integrated Approach

    Science.gov (United States)

    Wang, M.

    2006-05-01

    Quantitative determination of spatially and temporally varied groundwater recharge from precipitation is a complex issue involving many control factors, and investigators face great challenges for quantifying the relationship between groundwater recharge and its control factors. In fact, its quantification is a complex process in which unstructured decisions are generally involved. The Analytic Hierarchy Process (AHP) is a systematic method for a powerful and flexible decision making to determine priorities and make the best decision when both qualitative and quantitative aspects of a decision need to be accounted for. Moreover, through a process of reducing complex decisions to a series of one-on-one comparisons, then synthesizing the results, the rationale can clearly be understood for making the best decision. In this study, a systematic and integrated approach for estimation of spatially and temporally varied groundwater recharge from precipitation is proposed, in which the remote sensing, GIS, AHP, and modeling techniques are coupled. A case study is presented for demonstration of its application. Based on field survey and information analyses, the pertinent factors for groundwater recharge are assessed and the dominating factors are identified. An analytical model is then established for estimation of the spatially and temporally varied groundwater recharge from precipitation in which the contribution potentials to groundwater recharge and relative weights of those dominating factors are taken into account. The contribution potentials can be assessed by adopting fuzzy membership functions and integrating expert opinions. The weight for each of the dominating factors can systematically be determined through coupling of the RS, GIS, and AHP techniques. To reduce model uncertainty, this model should be further calibrated systematically and validated using even limited groundwater field data such as observed groundwater heads and groundwater discharges into

  3. MODIS-aided statewide net groundwater-recharge estimation in Nebraska.

    Science.gov (United States)

    Szilagyi, Jozsef; Jozsa, Janos

    2013-01-01

    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. PMID:23216050

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

    International Nuclear Information System (INIS)

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

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

    DEFF Research Database (Denmark)

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

    2002-01-01

    –130 mm/yr, with an average value of 25 mm/yr. Preliminary results of recharge estimate using 36Cl data suggests lower direct infiltration rates, but further studies are needed. The combination of hydro-chemical, isotopic and geophysical investigations show that the recharge area extends well beyond......A multi-disciplinary study is being carried out on recharge to the Karoo sandstone aquifer in the western part of Zimbabwe, where recharge is controlled by the presence of a thick, confining basalt layer. The aquifer is geographically extensive, and has been identified throughout the southern part...... 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...

  6. Recharge sources and hydrogeochemical evolution of groundwater in the coal-mining district of Jiaozuo, China

    Science.gov (United States)

    Huang, Pinghua; Chen, Jiansheng

    2012-06-01

    Investigations in the Jiaozuo coal-mining district (China) aim to link water-inrush aquifers with the sources of groundwater recharge. Concentrations of TDS, HCO{3/-}, Cl- and Na+ in the groundwater samples gradually decrease with increasing depth; in contrast, the factor 1 value of the Q-mode analysis gradually increases, which indicates that the deep groundwater may upflow, recharging the aquifers near the faulted zone. Some groundwater samples (above the local meteoric water line and `evaporation line 1') may originate from recharge by infiltrating local rainfall. Spring and river samples are symmetrically distributed on the regression line of the Ordovician and Carboniferous limestone aquifer groundwater (δ2H = 3.76 × δ18O - 31.77) and may, therefore, originate from groundwater recharge in the northern Taihang mountains. This mechanism is supported by the observation that groundwater levels change with rainfall. According to radiocarbon residence-time estimates, two groundwater sample sites may have been recharged during the late glacial stage.

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

    Science.gov (United States)

    Sophocleous, M.

    2005-01-01

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

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

    OpenAIRE

    Gates, John B.; Edmunds, W. Michael; Darling, George; Ma, Jinzhu; Pang, Zhonghe; De Young, A

    2008-01-01

    Sources of groundwater recharge to the Badain Jaran Desert in China have been investigated using geochemical and isotopic techniques. Stable isotope compositions (δ18O and δ2H) of shallow groundwater and surface water from oasis lakes evolve from a starting composition considerably depleted compared to local unsaturated zone moisture, confirming inferences from chloride mass balance that direct infiltration of precipitation is not a volumetrically important source of recharge to the shallow a...

  9. Silt and gas accumulation beneath an artificial recharge spreading basin, Southwestern Utah, U.S.A.

    Science.gov (United States)

    Heilweil, V.M.; Solomon, D.K.; Ortiz, G.

    2009-01-01

    Sand Hollow Reservoir in southwestern Utah, USA, is operated for both surface-water storage and artificial recharge to the underlying Navajo Sandstone. The total volume of estimated artificial recharge between 2002 and 2007 is 85 million cubic meters (69,000 acre-feet). Since 2002, artificial recharge rates have generally been declining and are inversely correlated with the increasing surface area of the reservoir. Permeability testing of core samples retrieved from beneath the reservoir indicates that this decline may not be due to silt accumulation. Artificial recharge rates also show much seasonal variability. Calculations of apparent intrinsic permeability show that these variations can only partly be explained by variation in water viscosity associated with seasonal changes in water temperature. Sporadic seasonal trends in recharge rates and intrinsic permeability during 2002-2004 could be associated with the large fluctuations in reservoir elevation and wetted area. From 2005 through 2007, the reservoir was mostly full and there has been a more consistent seasonal pattern of minimum recharge rates during the summer and maximum rates during the autumn. Total dissolved-gas pressure measurements indicate the presence of biogenic gas bubbles in the shallow sediments beneath the shallower parts of Sand Hollow Reservoir when the water is warmer. Permeability reduction associated with this gas clogging may contribute to the decrease in artificial recharge rates during the spring and summer, with a subsequently increasing recharge rates in the autumn associated with a decline in volume of gas bubbles. Other possible causes for seasonal variation in artificial recharge rates require further investigation.

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

    Directory of Open Access Journals (Sweden)

    B. Leterme

    2012-08-01

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

  11. Vadose zone-attenuated artificial recharge for input to a ground water model.

    Science.gov (United States)

    Nichols, William E; Wurstner, Signe K; Eslinger, Paul W

    2007-01-01

    Accurate representation of artificial recharge is requisite to calibration of a ground water model of an unconfined aquifer for a semiarid or arid site with a vadose zone that imparts significant attenuation of liquid transmission and substantial anthropogenic liquid discharges. Under such circumstances, artificial recharge occurs in response to liquid disposal to the vadose zone in areas that are small relative to the ground water model domain. Natural recharge, in contrast, is spatially variable and occurs over the entire upper boundary of a typical unconfined ground water model. An improved technique for partitioning artificial recharge from simulated total recharge for inclusion in a ground water model is presented. The improved technique is applied using data from the semiarid Hanford Site. From 1944 until the late 1980s, when Hanford's mission was the production of nuclear materials, the quantities of liquid discharged from production facilities to the ground vastly exceeded natural recharge. Nearly all hydraulic head data available for use in calibrating a ground water model at this site were collected during this period or later, when the aquifer was under the diminishing influence of the massive water disposals. The vadose zone is typically 80 to 90 m thick at the Central Plateau where most production facilities were located at this semiarid site, and its attenuation of liquid transmission to the aquifer can be significant. The new technique is shown to improve the representation of artificial recharge and thereby contribute to improvement in the calibration of a site-wide ground water model.

  12. Impact of climate on groundwater recharge in the crystalline basement rocks aquifer of Northern Ghana

    Science.gov (United States)

    Koffi, K. V.

    2015-12-01

    Water is the cornerstone of human life and for all economic developments. West Africa and specifically Ghana are no exception to this reality.Northern Ghana is characterized by a semi-arid climate, with prolonged dry season (7 months of very few rainfall) leading to the drying up of many rivers and streams. In addition, rainfall is highly variable in space and time. Therefore, surface water is unreliable and insufficient to meet the water demands for socio-economic development in this area. As a result, the area is heavily dependent on groundwater for domestic water supply as well as for dry season irrigation of vegetables (cash crops).However, aquifers in northern Ghana are dominantly the hard rock type (Crystalline basement rock). This aquifer has no primary porosity and may not be able to sustain the increasing demand on the resource. Further, climate change may worsen the situation as recharge is dependent on rainfall in northern Ghana. Therefore, it is important to understand exactly how climate change will impact on recharge to the groundwater for sustainable development and management of the resource.Previous groundwater studies in Northern Ghana barely analyzed the combined impacts of Climate change on the recharge to the groundwater. This research is aimed at determining the current relationship between groundwater recharge and rainfall and to use the relationships to determine the impacts of changes in climate on the groundwater recharge. The results will inform plans and strategies for sustainably managing groundwater resources in Ghana and the Volta basin.

  13. Groundwater recharge and time lag measurement through Vertosols using impulse response functions

    Science.gov (United States)

    Hocking, Mark; Kelly, Bryce F. J.

    2016-04-01

    Throughout the world there are many stressed aquifers used to support irrigated agriculture. The Condamine River catchment (southern Queensland, Australia) is one example of a globally significant agricultural region where groundwater use has exceeded recharge over the last 50 years. There is a high dependence on groundwater in this catchment, because yearly rainfall is highly variable, and actual evapotranspiration often exceeds rainfall. To better manage the aquifer there is a need to correctly conceptualise the primary inputs and outputs of the system, and characterise the lags in system response to all forcings. In catchment models it is particularly important to correctly proportion diffuse (areal) rainfall recharge and to account for the lag between rainfall and recharge at the water table. Throughout large portions of the Condamine Catchment, groundwater levels are now 20 or more metres below the ground surface. This study aimed to better quantify the lag between rainfall and recharge at the water table using the predefined impulse response function in continuous time method (PIRFICT; von Asmuth et al., 2002; von Asmuth, 2012). The PIRFICT method was applied to 255 multi-decadal groundwater level data sets throughout the catchment. Inputs into the modelling include rainfall, irrigation deep drainage, stream water level, evapotranspiration, and groundwater extractions. As an independent check the PIRFICT model derived diffuse recharge estimates are compared to point lysimeter and geochemical recharge estimates in the Vertosol soils within this catchment. It is estimated using the PIRFICT method that in the Condamine Catchment between 1990 and 2012, the mean rain-derived groundwater recharge is 4.4 mm/year. Mean groundwater response from rainfall was determined to be 5.3 years: range 188 days to 48 years. The recharge estimates are consistent with both geochemical and lysimeter point measurements of recharge. It is concluded that where extensive groundwater

  14. Environmental isotope and hydrochemical investigation on groundwater recharge and dynamics of the coastal sedimentary aquifers of Tiruvadanai, Tamilnadu State, India

    International Nuclear Information System (INIS)

    Recharge processes and dynamics of the Tiruvadanai aquifers were investigated using environmental isotopes and hydrochemistry, in conjunction with hydrogeological data. Hydrochemical characterization of the groundwaters indicated that the shallow (3-Cl) to saline type waters and the deeper (350-500 m) Cretaceous aquifer (confined) is a NaCl type. The concentration of various chemical species along the general groundwater flow direction (northwest to east) showed a trend with a decrease in Mg2+ and Ca2+ and an increase in Na+ and K+ in both the aquifers. This change could be attributed to ion-exchange process. Higher pH values of Cretaceous aquifer samples (7.4-8.6) could also be responsible for the lowering of Mg2+ and Ca2+ concentrations by facilitating precipitation of carbonates. A δ2H-δ18O plot shows that the Tertiary aquifer samples fall on an evaporation line. The aquifer 3H values near the ephemeral rivers range from 2 to 5 TU while those away from the rivers have 14CDIC model ages range from 1 to 13 Ka BP. The Cretaceous aquifer samples had 3H values 14CDIC model ages are >20 ka BP, indicating palaeo-waters. Based on 14C model ages, the groundwater velocity was estimated (Tertiary aquifers: 10-2-10-3 m·d-1; Cretaceous aquifer: 10-3 m·d-1). A 13CDIC enrichment along the flowpath of the Cretaceous aquifer was observed and could be due to carbonate mineral dissolution. From the investigation, four types of recharge processes to the aquifer system are discerned, with the overall modern recharge component being low. The Cretaceous aquifer contains fossil groundwaters and hence, the resources may be finite and thus, their exploitation is mining. The most suitable river for implementing large-scale artificial recharge measures was also identified. (author)

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

    Directory of Open Access Journals (Sweden)

    Lin Deng

    2015-01-01

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

  16. Sustainable Hydro Assessment and Groundwater Recharge Projects (SHARP) in Germany - Water Balance Models

    Science.gov (United States)

    Niemand, C.; Kuhn, K.; Schwarze, R.

    2010-12-01

    SHARP is a European INTERREG IVc Program. It focuses on the exchange of innovative technologies to protect groundwater resources for future generations by considering the climate change and the different geological and geographical conditions. Regions involved are Austria, United Kingdom, Poland, Italy, Macedonia, Malta, Greece and Germany. They will exchange practical know-how and also determine know-how demands concerning SHARP’s key contents: general groundwater management tools, artificial groundwater recharge technologies, groundwater monitoring systems, strategic use of groundwater resources for drinking water, irrigation and industry, techniques to save water quality and quantity, drinking water safety plans, risk management tools and water balance models. SHARP Outputs & results will influence the regional policy in the frame of sustainable groundwater management to save and improve the quality and quantity of groundwater reservoirs for future generations. The main focus of the Saxon State Office for Environment, Agriculture and Landscape in this project is the enhancement and purposive use of water balance models. Already since 1992 scientists compare different existing water balance models on different scales and coupled with groundwater models. For example in the KLIWEP (Assessment of Impacts of Climate Change Projections on Water and Matter Balance for the Catchment of River Parthe in Saxony) project the coupled model WaSiM-ETH - PCGEOFIM® has been used to study the impact of climate change on water balance and water supplies. The project KliWES (Assessment of the Impacts of Climate Change Projections on Water and Matter Balance for Catchment Areas in Saxony) still running, comprises studies of fundamental effects of climate change on catchments in Saxony. Project objective is to assess Saxon catchments according to the vulnerability of their water resources towards climate change projections in order to derive region-specific recommendations for

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

    International Nuclear Information System (INIS)

    Intensive agricultural irrigation and overdraft of groundwater in the Central Valley of California profoundly affect the regional quality and availability of shallow groundwater resources. In the natural state, the δ18O values of groundwater were relatively homogeneous (mostly -7.0 ± 0.5 per-thousand), reflecting local meteoric recharge that slowly (1-3m/yr) flowed toward the valley axis. Today, on the west side of the valley, the isotope distribution is dominated by high 18O enclosures formed by recharge of evaporated irrigation waters, while the east side has bands of low 18O groundwater indicating induced recharge from rivers draining the Sierra Nevada mountains. Changes in δ18O values caused by the agricultural recharge strongly correlate with elevated nitrate concentrations (5 to >100 mg/L) that form pervasive, non-point source pollutants. Small, west-side cities dependent solely on groundwater resources have experienced increases of >1.0 mg/L per year of nitrate for 10-30 years. The resultant high nitrates threaten the economical use of the groundwater for domestic purposes, and have forced some well shut-downs. Furthermore, since >80% of modern recharge is now derived from agricultural irrigation, and because modern recharge rates are ∼10 times those of the natural state, agricultural land retirement by urbanization will severely curtail the current safe-yields and promote overdraft pumping. Such overdrafting has occurred in the Sacramento metropolitan area for ∼40 years, creating cones of depression ∼25m deep. Today, groundwater withdrawal in Sacramento is approximately matched by infiltration of low 18O water (-11.0 per-thousand) away from the Sacramento and American Rivers, which is estimated to occur at 100-300m/year from the sharp 18O gradients in our groundwater isotope map

  18. Design, operation, and monitoring capability of an experimental artificial-recharge facility at East Meadow, Long Island, New York

    Science.gov (United States)

    Schneider, B.J.; Oaksford, E.T.

    1986-01-01

    Artificial recharge with tertiary-treated sewage is being tested at East Meadow to evaluate the physical and chemical effects on the groundwater system. The recharge facility contains 11 recharge basins and 5 injection wells and is designed to accept 4 million gallons of reclaimed water per day. Of the 11 basins, 7 are recently constructed and will accept 0.5 million gallons per day each. An observation manhole (12-foot inside diameter and extending 16 feet below the basin floor) was installed in each of two basins to enable monitoring and sampling of percolating reclaimed water in the unsaturated zone with instruments such as tensiometers, gravity lysimeters, thermocouples, and soil-gas samplers. Five shallow (100-feet deep) injection wells will each return 0.5 million gallons per day to the groundwater reservoir. Three types of injection-well design are being tested; the differences are in the type of gravel pack around the well screen. When clogging at the well screen occurs, redevelopment should restore the injection capability. Flow to the basins and wells is regulated by automatic flow controllers in which a desired flow rate is maintained by electronic sensors. Basins can also operate in a constant-head mode in which a specified head is maintained in the basin automatically. An observation-well network consisting of 2-inch- and 6-inch-diameter wells was installed within a 1-square-mile area at the recharge facility to monitor aquifer response and recharge. During 48 days of operation within a 17-week period (October 1982 through January 1983), 88.5 million gallons of reclaimed water was applied to the shallow water table aquifer through the recharge basins. A 4.29-foot-high groundwater mound developed during a 14-day test; some water level increase associated with the mound was detected 1,000 ft from the basins. Preliminary water quality data from wells affected by reclaimed water show evidence that mechanisms of mixing, dilution, and dispersion are

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

    Science.gov (United States)

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

    2015-01-01

    Simulating groundwater flow in basin-fill aquifers of the semiarid southwestern United States commonly requires decisions about how to distribute aquifer recharge. Precipitation can recharge basin-fill aquifers by direct infiltration and transport through faults and fractures in the high-elevation areas, by flowing overland through high-elevation areas to infiltrate at basin-fill margins along mountain fronts, by flowing overland to infiltrate along ephemeral channels that often traverse basins in the area, or by some combination of these processes. The importance of accurately simulating recharge distributions is a current topic of discussion among hydrologists and water managers in the region, but no comparative study has been performed to analyze the effects of different recharge distributions on groundwater simulations. This study investigates the importance of the distribution of aquifer recharge in simulating regional groundwater flow in basin-fill aquifers by calibrating a groundwater-flow model to four different recharge distributions, all with the same total amount of recharge. Similarities are seen in results from steady-state models for optimized hydraulic conductivity values, fit of simulated to observed hydraulic heads, and composite scaled sensitivities of conductivity parameter zones. Transient simulations with hypothetical storage properties and pumping rates produce similar capture rates and storage change results, but differences are noted in the rate of drawdown at some well locations owing to the differences in optimized hydraulic conductivity. Depending on whether the purpose of the groundwater model is to simulate changes in groundwater levels or changes in storage and capture, the distribution of aquifer recharge may or may not be of primary importance. PMID:24841767

  20. Recharge sources and hydrogeochemical evolution of groundwater in alluvial basins in arid central Australia

    Science.gov (United States)

    Vanderzalm, J. L.; Jeuken, B. M.; Wischusen, J. D. H.; Pavelic, P.; Le Gal La Salle, C.; Knapton, A.; Dillon, P. J.

    2011-01-01

    SummaryIt is necessary to define the role of various sources of recharge in the surficial alluvial aquifer system in arid Alice Springs in central Australia, for future management of water resources in the region. Multiple sources of natural recharge include infiltration from ephemeral stream flow in the Todd River; groundwater throughflow between connected alluvial basins; regional groundwater flow from the underlying Tertiary aquifer; and diffuse recharge. In addition treatment, storage and irrigation reuse of Alice Springs' waste water has resulted in additional recharge of effluent, via infiltration. Water resource management plans for the region include effluent reuse through Soil Aquifer Treatment (SAT) within one of the connected alluvial basins, with the purpose of managing the excess waste water overflows while also supplementing groundwater resources for irrigation and protecting their quality. Hydrogeochemical tracers, chloride and the stable isotopes of water, were used in a three-member mixing model to define and quantify the major recharge sources. The mixing model was not sensitive enough to quantify minor contributions from effluent in groundwater that were identified only by an evaporated isotopic signature. The contribution of the multiple recharge sources varied spatially with proximity to the recharge source; with Todd River, effluent and Town Basin throughflow contributing to the Inner Farm Basin groundwater. The Outer Farm Basin was largely influenced by the Todd River, the Inner Farm Basin throughflow and the older Tertiary aquifer. While Inner Farm groundwater throughflow contains an effluent component, only Outer Farm Basin groundwater near the interface between the two basins clearly illustrated an effluent signature. Aside from this, effluent recharge was not evident in the Outer Farm Basin, indicating that past unmanaged recharge practices will not mask signs of Managed Aquifer Recharge through the Soil Aquifer Treatment (SAT) operation

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

    Science.gov (United States)

    Taylor, R. G.

    2015-12-01

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

  2. Impacts of urbanization on groundwater quality and recharge in a semi-arid alluvial basin

    Science.gov (United States)

    Carlson, Mark A.; Lohse, Kathleen A.; McIntosh, Jennifer C.; McLain, Jean E. T.

    2011-10-01

    SummaryThe management of groundwater resources is paramount in semi-arid regions experiencing urban development. In the southwestern United States, enhancing recharge of urban storm runoff has been identified as a strategy for augmenting groundwater resources. An understanding of how urbanization may impact the timing of groundwater recharge and its quality is a prerequisite for mitigating water scarcity and identifying vulnerability to contamination. We sampled groundwater wells along the Rillito Creek in southern Arizona that had been previously analyzed for tritium in the late 1980s to early 1990s and analyzed samples for tritium ( 3H) and helium-3 ( 3H/ 3He) to evaluate changes in 3H and age date groundwaters. Groundwater samples were also analyzed for chlorofluorocarbons (CFCs) and basic water quality metrics. Substantial changes in 3H values from waters sampled in the early 1990s compared to 2009 were identified after accounting for radioactive decay and indicate areas of rapid recharge. 3H- 3He groundwater ages ranged from 22 years before 2009 to modern recharge. CFC-11, -12 and -113 concentrations were anomalously high across the basin, and non-point source pollution in runoff and/or leaky infrastructure was identified as the most plausible source of this contamination. CFCs were strongly and positively correlated to nitrate ( r2 = 0.77) and a mobile trace metal, nickel ( r2 = 0.71), suggesting that solutes were derived from a similar source. Findings from this study suggest new waters from urban non-point sources are contributing to groundwater recharge and adversely affecting water quality. Reducing delivery of contaminants to areas of focused recharge will be critical to protect future groundwater resources.

  3. Hydrological modeling to assess capillary rise contribution to satisfy crop water requirement and groundwater recharge

    Science.gov (United States)

    Wassar, Fatma; Gandolfi, Claudio; chiaradia, Enrico Antonio

    2016-04-01

    Quantitative understanding of the process of groundwater recharge and capillary rise are fundamental factors on water balance and sustainable management carried out in irrigated areas with shallow groundwater tables. Two tested hydrological models (Wassar et al., 2014) SWAP (Van Dam et al., 1997) and IDRAGRA (Gandolfi et al., 2011) were applied to assess capillary rise contribution to satisfy maize water requirement and groundwater recharge from a shallow water table located in Lombardy region, northern of Italy during two agricultural seasons (2010 and 2011). At the beginning the two models were run using the daily variation of groundwater table and it was found that during 2010 season, capillary rise was similar for both and is contributing by 41% (IDRAGRA) and 46% (SWAP) of the total maize water requirement. During 2011 season, the estimated capillary flux with SWAP model was higher than that with IDRAGRA. The capillary rise was able to contribute more than 50% of the total maize requirement for both models. On the other side, both models showed a negligible deep percolation in comparison to the capillary flux and in comparison to the 2010 season. Later, groundwater table depths were fixed virtually at 0.8m, 1m, 1.5m, 2m, and 3m. The aim of considering fixed groundwater table depths was to unveil at which depth the groundwater table contributes majorly to satisfy the crop water requirement and how much we can have groundwater recharge. One major finding was that the capillary rise from groundwater decreases with the increase of the groundwater table depth. A higher contribution is observed when the water table is higher or equal to 1m. When the water table depth reached 2m the capillary was steel contributing to maize water requirement for both models and during the two agricultural seasons. As far as the groundwater recharge is concerned, we found that net recharge tended to increase as the groundwater table depth increased. For both models the net recharge was

  4. Ground-Water Recharge in the Arid and Semiarid Southwestern United States

    Science.gov (United States)

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

    2007-01-01

    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 naturally occurring multidecadal droughts unlike any in the modern instrumental record. Any anthropogenically induced climate change will likely reduce ground-water recharge through diminished snowpack at higher elevations. Future changes in El Ni?o and monsoonal patterns, both crucial to precipitation in the study area, are highly uncertain in current models. Current land-use modifications influence ground-water recharge through vegetation, irrigation, and impermeable area. High mountain 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 Paleozoic aquifers in mountainous recharge areas

  5. Gas transport below artificial recharge ponds: Insights from dissolved noble gases and a dual gas (SF6 and 3He) tracer experiment

    OpenAIRE

    Clark, JF; Hudson, GB; Avisar, D

    2005-01-01

    A dual gas tracer experiment using sulfur hexafluoride (SF6) and an isotope of helium (3He) and measurements of dissolved noble gases was performed at the El Rio spreading grounds to examine gas transport and trapped air below an artificial recharge pond with a very high recharge rate (∼4 m day-1). Noble gas concentrations in the groundwater were greater than in surface water due to excess air formation showing that trapped air exists below the pond. Breakthrough curves of SF6 and 3He at two ...

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

    Science.gov (United States)

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

    2016-03-01

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

  7. An Analysis on Groundwater Recharge by Mathematical Model in Inclined Porous Media

    OpenAIRE

    Pathak, Shreekant P.; Singh, Twinkle

    2014-01-01

    The present paper discusses the analysis of solution of groundwater flow in inclined porous media. The problem related to groundwater flow in inclined aquifers is usually common in geotechnical and hydrogeology engineering activities. The governing partial differential equation of one-dimensional groundwater recharge problem has been formed by Dupuit's assumption. Three cases have been discussed with suitable boundary conditions and different slopes of impervious incline boundary. The numeric...

  8. Environmental isotope and hydrochemical investigation on groundwater recharge and dynamics of the coastal sedimentary aquifers of Tiruvadanai, Tamilnadu State, India

    International Nuclear Information System (INIS)

    Recharge processes and dynamics of the Tiruvadanai aquifers were investigated using environmental isotopes and hydro-chemistry, in conjunction with hydrogeological data. Hydro-chemical characterization of the groundwaters indicated that the shallow (2+ and Ca2+ and an increase in Na+ and K+ in both the aquifers. This could be attributed to ion-exchange process. A higher pH value of Cretaceous aquifer samples (7.4-8.6) could also be responsible for the lowering of Mg2+ and Ca2+ concentrations by facilitating precipitation of carbonates in them. δ2H-δ18O plot of the Tertiary aquifer samples fall on an evaporation line. Its 3H values near the ephemeral rivers range from 2 to 5 TU while those away from the rivers have 14CDIC model ages range from 1 to 13 ka BP. The Cretaceous aquifer samples measured 3H values 14CDIC model ages are >20 ka BP, indicating palaeo-waters. Based on 14C model ages, the groundwater velocity was estimated (Tertiary aquifers: 10-2 - 10-3 m.d-1; Cretaceous aquifer: 10-3 m.d-1). The 13CDIC enrichment along the flowpath of Cretaceous aquifer was observed and that could be due to carbonate minerals dissolution. From the investigation, four types of recharge processes to the aquifer system are discerned, with the overall modern recharge component being low. The Cretaceous aquifer contains fossil groundwaters and hence the resources may be finite and their exploitation is mining. The suitable river for implementing large-scale artificial recharge measures was identified. (author)

  9. Understanding Groundwater Storage Changes and Recharge in Rajasthan, India through Remote Sensing

    Directory of Open Access Journals (Sweden)

    Pennan Chinnasamy

    2015-10-01

    Full Text Available Groundwater management practices need to take hydrogeology, the agro-climate and demand for groundwater into account. Since agroclimatic zones have already been demarcated by the Government of India, it would aid policy makers to understand the status of groundwater recharge and discharge in each agroclimatic zone. However, developing effective policies to manage groundwater at agroclimatic zone and state levels is constrained due to a paucity of temporal data and information. With the launch of the Gravity Recovery and Climate Experiment (GRACE mission in 2002, it is now possible to obtain frequent data at broad spatial scales and use it to examine past trends in rain induced recharge and groundwater use. In this study, the GRACE data were used to estimate changes to monthly total water storage (TWS and groundwater storage in different agroclimatic zones of Rajasthan, India. Furthermore, the long-term annual and seasonal groundwater storage trends in the state were estimated using the GRACE data and the trends were compared with those in rainfall data. The methodology based on GRACE data was found to be useful in detecting large scale trends in groundwater storage changes covering different agroclimatic zones. The analysis of data shows that groundwater storage trends depend on rainfall in previous years and, therefore, on the antecedent moisture conditions. Overall, the study indicates that if suitable groundwater recharge methods and sites are identified for the state, there is potential to achieve more groundwater recharge than what is currently occurring and, thus, enhancing the availability of water for irrigated agriculture.

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

    Science.gov (United States)

    Babamaaji, R. A.; Lee, J.

    2012-12-01

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

  11. Groundwater recharge and capillary rise in a clayey catchment: modulation by topography and the Arctic Oscillation

    OpenAIRE

    T. M. Schrøder; D. Rosbjerg

    2004-01-01

    The signature left by capillary rise in the water balance is investigated for a 16 km2 clayey till catchment in Denmark. Integrated modelling for 1981–99 substantiates a 30% uphill increase in average net recharge, caused by the reduction in capillary rise when the water table declines. Calibration of the groundwater module is constrained by stream flow separation and water table wells. Net recharge and a priori parameterisation has been estimated from those same data, an automatic rain ga...

  12. Groundwater recharge and capillary rise in a clayey catchment: modulation by topography and the Arctic Oscillation

    OpenAIRE

    T. M. Schrøder; D. Rosbjerg

    2002-01-01

    International audience The signature left by capillary rise in the water balance is investigated for a 16 km2 clayey till catchment in Denmark. Integrated modelling for 1981?99 substantiates a 30% uphill increase in average net recharge, caused by the reduction in capillary rise when the water table declines. Calibration of the groundwater module is constrained by stream flow separation and water table wells. Net recharge and a priori parameterisation has been estimated from those same dat...

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2016-02-01

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

  15. Modelling of groundwater mound formation resulting from transient recharge

    Science.gov (United States)

    Rai, S. N.; Ramana, D. V.; Thiagarajan, S.; Manglik, A.

    2001-06-01

    An analytical solution of a linearized Boussinesq equation is obtained to predict water table fluctuations as a result of time varying recharge from a strip basin for any number of recharge cycles. The analytical solution is obtained by using finite Fourier sine transform. Applications of the solution for the prediction of water table fluctuations and sensitivity analysis are demonstrated with the help of example problems.

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

    Directory of Open Access Journals (Sweden)

    Brioch Hemmings

    2015-09-01

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

  17. Estimation of Groundwater Recharge Using Tracers and Numerical Modeling in the North China Plain

    Directory of Open Access Journals (Sweden)

    Qinghua Wu

    2016-08-01

    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

  18. A simulation model to assess groundwater recharge over Europe's karst regions

    Directory of Open Access Journals (Sweden)

    A. Hartmann

    2014-11-01

    Full Text Available Karst develops through the dissolution of carbonate rock and is a major source of groundwater contributing up to half of the total drinking water supply in some European countries. Previous approaches to model future water availability in Europe are either too-small scale or do not incorporate karst processes, i.e. preferential flow paths. This study presents the first simulations of groundwater recharge in all karst regions in Europe with a parsimonious karst hydrology model. A novel parameter confinement strategy combines a priori information with recharge-related observations (actual evapotranspiration and soil moisture at locations across Europe while explicitly identifying uncertainty in the model parameters. Europe's karst regions are divided into 4 typical karst landscapes (humid, mountain, Mediterranean and desert by cluster analysis and recharge is simulated from 2002 to 2012 for each karst landscape. Mean annual recharge ranges from negligible in deserts to > 1 m a−1 in humid regions. The majority of recharge rates ranges from 20–50% of precipitation and are sensitive to sub-annual climate variability. Simulation results are consistent with independent observations of mean annual recharge and significantly better than other global hydrology models that do not consider karst processes (PCR-GLOBWB, WaterGAP. Global hydrology models systematically underestimate karst recharge implying that they over-estimate actual evapotranspiration and surface runoff. Karst water budgets and thus information to support management decisions regarding drinking water supply and flood risk are significantly improved by our model.

  19. Identifying long-term empirical relationships between storm characteristics and episodic groundwater recharge

    Science.gov (United States)

    Tashie, Arik M.; Mirus, Benjamin B.; Pavelsky, Tamlin M.

    2016-01-01

    Shallow aquifers are an important source of water resources and provide base flow to streams; yet actual rates of groundwater recharge are difficult to estimate. While climate change is predicted to increase the frequency and magnitude of extreme precipitation events, the resulting impact on groundwater recharge remains poorly understood. We quantify empirical relations between precipitation characteristics and episodic groundwater recharge for a wide variety of geographic and land use types across North Carolina. We extract storm duration, magnitude, average rate, and hourly weighted intensity from long-term precipitation records over periods of 12-35 years at 10 locations. Using time series of water table fluctuations from nearby monitoring wells, we estimate relative recharge to precipitation ratios (RPR) to identify statistical trends. Increased RPR correlates with increased storm duration, whereas RPR decreases with increasing magnitude, average rate, and intensity of precipitation. Agricultural and urban areas exhibit the greatest decrease in RPR due to increasing storm magnitude, average rate, and intensity, while naturally vegetated areas exhibit a larger increase in RPR with increased storm duration. Though RPR is generally higher during the winter than the summer, this seasonal effect is magnified in the Appalachian and Piedmont regions. These statistical trends provide valuable insights into the likely consequences of climate and land use change for water resources in subtropical climates. If, as predicted, growing seasons lengthen and the intensity of storms increases with a warming climate, decreased recharge in Appalachia, the Piedmont, and rapidly growing urban areas of the American Southeast could further limit groundwater availability.

  20. Identifying long term empirical relationships between storm characteristics and episodic groundwater recharge

    Science.gov (United States)

    Tashie, Arik; Mirus, Benjamin B.; Pavelsky, Tamlin

    2016-01-01

    Shallow aquifers are an important source of water resources and provide base flow to streams; yet actual rates of groundwater recharge are difficult to estimate. While climate change is predicted to increase the frequency and magnitude of extreme precipitation events, the resulting impact on groundwater recharge remains poorly understood. We quantify empirical relations between precipitation characteristics and episodic groundwater recharge for a wide variety of geographic and land use types across North Carolina. We extract storm duration, magnitude, average rate, and hourly weighted intensity from long-term precipitation records over periods of 12–35 years at 10 locations. Using time series of water table fluctuations from nearby monitoring wells, we estimate relative recharge to precipitation ratios (RPR) to identify statistical trends. Increased RPR correlates with increased storm duration, whereas RPR decreases with increasing magnitude, average rate, and intensity of precipitation. Agricultural and urban areas exhibit the greatest decrease in RPR due to increasing storm magnitude, average rate, and intensity, while naturally vegetated areas exhibit a larger increase in RPR with increased storm duration. Though RPR is generally higher during the winter than the summer, this seasonal effect is magnified in the Appalachian and Piedmont regions. These statistical trends provide valuable insights into the likely consequences of climate and land use change for water resources in subtropical climates. If, as predicted, growing seasons lengthen and the intensity of storms increases with a warming climate, decreased recharge in Appalachia, the Piedmont, and rapidly growing urban areas of the American Southeast could further limit groundwater availability.

  1. Estimation of future groundwater recharge using climatic analogues and Hydrus-1D

    Directory of Open Access Journals (Sweden)

    B. Leterme

    2012-01-01

    Full Text Available 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's based soil water balance model Hydrus-1D and meteorological time series from analogue stations. Water balance calculations showed that transition from a temperate oceanic to a warmer subtropical climate without rainfall seasonality is expected to yield a decrease in groundwater recharge (−12% for the chosen representative analogue station of Gijon, Northern Spain. Based on a time series of 24 yr of daily climate data, the long-term average annual recharge decreased from 314 to 276 mm, although total rainfall was higher (947 mm in the warmer climate compared to the current temperate climate (899 mm. This is due to a higher soil evaporation (233 mm versus 206 mm and higher plant transpiration (350 versus 285 mm under the warmer climate.

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

    Directory of Open Access Journals (Sweden)

    S. Eeman

    2012-10-01

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

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

    Directory of Open Access Journals (Sweden)

    S. Eeman

    2012-01-01

    Full Text Available In coastal zones with saline groundwater, fresh groundwater lenses may form due to infiltration of rain water. The thickness of both the lens and the mixing zone, determines fresh water availability for plant growth. Due to recharge variation, the thickness of the lens and the mixing zone are not constant, which may adversely affect agricultural and natural vegetation if saline water reaches the root zone during the growing season. In this paper, we study the response of thin lenses and their mixing zone to variation of recharge. The recharge is varied using sinusoids with a range of amplitudes and frequencies. We vary lens characteristics by varying the Rayleigh number and Mass flux ratio of saline and fresh water, as these dominantly influence the thickness of thin lenses and their mixing zone. Numerical results show a linear relation between the 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

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

    International Nuclear Information System (INIS)

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

  5. Assessment of groundwater recharge and discharge in sub-catchments of Indus basin

    International Nuclear Information System (INIS)

    Groundwater discharge and recharge investigation was carried out in a selected sub-catchment of Indus Basin (Chashma Area) under an IAEA CRP. Sixteen sampling points were selected in the study area including fourteen groundwater and two canal water samples. Seven groundwater sampling points were selected in discharging area and the same numbers of sampling points were selected in recharging area. The first sampling campaign from discharging area was conducted in February 2011 and the second sampling campaign was carried out in March 2011. The electrical conductivity, toital dissolved salts, pH and temperature were measured in the field. The coordinates of the sampling points were recorded using GPS. All the collected samples were analyzed for stable isotopes (/sup 18/O, /sup 2/H). Plot of /sup 18/O vs. /sup 2/H values of surface water and groundwater along with the Global Meteoric Water Line (GMWL) is shown. /sup 18/O values of groundwater vary over a narrow range from -11.3 to -8.2% and /sup 2/H values vary from -76.3 to -53.8%. All groundwater samples except two shallow ones have highly depleted isotopic composition (close to the river/canal water). It means that these locations are recharged by the surface water. Two shallow groundwater samples show mixing of rain water with canal/river water. (orig./A.B.)

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

    Science.gov (United States)

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

    2013-12-01

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

  7. Hydrometeorology of the Dhofar cloud forest and its implications for groundwater recharge

    Science.gov (United States)

    Friesen, J.; Mueller, T. H.; Zink, M.; Bawain, A. M., Sr.; Hildebrandt, A.

    2015-12-01

    Cloud forests have the ability to harvest cloud water or horizontal precipitation in addition to rainfall and, through rainfall re-distribution, provide markedly different infiltration and therefore recharge behavior. Forest interception studies required to formulate interception processes and to quantify the recharge relevant net precipitation are, however, often only possible at point or experimental plot scale and limited to the studied tree species. Groundwater recharge, in contrast, is often linked to groundwater aquifer boundaries and thus is located at the other end of the spatial scale. To be able to utilize findings from ecohydrological site studies for regional groundwater studies we regionalize field site studies through cloud forest distribution and rainfall interpolation in a semi-arid, data scarce region heavily dependent on groundwater resources. Through different rainfall scenarios, based on regular precipitation and on cloud forest modified precipitation, for two mountainous groundwater recharge catchments we can show that even moderately forested catchments provide up to 1/3 more precipitation through cloud water.

  8. Water-storage change measured with high-precision gravimetry at a groundwater recharge facility in Tucson, USA.

    Science.gov (United States)

    Creutzfeldt, B.; Kennedy, J.; Ferre, P. A.

    2012-12-01

    Groundwater depletion is a serious problem in many regions around the world. Artificial groundwater recharge is used for the short- and long-term storage of water in subsurface and can be an effective tool to prevent aquifer over-draft. Effective design and management of recharge facilities benefits from knowledge of the subsurface conditions and water-storage properties. In this study we combine different types of gravimeters and coupled hydrogeophysical inverse techniques to monitor subsurface water storage and to estimate subsurface hydraulic properties at the field scale. Water storage dynamics are continuously monitored with two iGrav™ superconducting gravimeters and three gPhones at three infiltration basins of the Tucson Water Southern Avra Valley Storage and Recovery Project facility. These continuous gravity observations are supported by time-lapse monitoring with absolute and spring gravimeters to map spatial gravity variations. Water level is monitored at 16 wells in the vicinity. The results of the first 6-month drying-wetting-drying cycle of the infiltration basins, during which 4,240,500 cubic meters (3,440 acre-feet) infiltrated over 53 days, are presented in this study. Gravity variations up to 170 μGal were observed. Collocated measurements show an overall good agreement of the different gravimeters. Distinct spatial variations of gravity change indicate variable water storage dynamics caused by subsurface heterogeneity at the field scale. Multiple gravimeter types combined with coupled inversion allows accurate tracking of subsurface water storage, which can improve the predictions of subsurface conditions and the water resources management of artificial recharge facilities.

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

    International Nuclear Information System (INIS)

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

  10. GIS and SBF for estimating groundwater recharge of a mountainous basin in the Wu River watershed, Taiwan

    Indian Academy of Sciences (India)

    Hsin-Fu Yeh; Hung-I Lin; Shing-Tsz Lee; Min-Hsiang Chang; Kuo-Chin Hsu; Cheng-Haw Lee

    2014-04-01

    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 resources poses a challenge to water resource management in Taiwan. However, assessing groundwater resources in mountainous basins is challenging due to limited information. In this study, a geographic information system (GIS) and stable base-flow (SBF) techniques were used to assess the characteristics of groundwater recharge considering the Wu River watershed in central Taiwan as a study area. First, a GIS approach was used to integrate five contributing factors: lithology, land cover/land use, lineaments, drainage, and slope. The weights of factors contributing to the groundwater recharge were obtained from aerial photos, geological maps, a land use database, and field verification. Second, the SBF was used to estimate the groundwater recharge in a mountainous basin scale. The concept of the SBF technique was to separate the base-flow from the total streamflow discharge in order to obtain a measure of groundwater recharge. The SBF technique has the advantage of integrating groundwater recharge across an entire basin without complex hydro-geologic modelling and detailed knowledge of the soil characteristics. In this study, our approach for estimating recharge provides not only an estimate of how much water becomes groundwater, but also explains the characteristics of a potential groundwater recharge zone.

  11. Estimate of shallow groundwater recharge in the Hadejia-Nguru Wetlands, semi-arid northeastern Nigeria

    Science.gov (United States)

    Goes, B. J. M.

    1999-06-01

    The Hadejia-Nguru Wetlands are annually inundated flood plains in semi-arid northeastern Nigeria. The area has a unique ecosystem that forms a natural barrier against the encroachment of the Sahara desert. Both the rich wetland vegetation and local farmers using shallow tube wells depend on a groundwater mound (with a water table less than 6 m below the surface) that is present in the unconfined aquifer under the flood-plain area. Using well records (1991-97) and a hydrogeologic profile based on piezometers that were monitored for two years, it is shown that recharge through the annually inundated flood plains is the source of the groundwater mound. Maintenance of the groundwater-recharge function of the flood plains depends on wet-season releases from two large upstream dams. On the basis of a water-budget method, the mean (1991-97) wet-season unconfined groundwater recharge in the flood-plain area between Hadejia and Nguru and in the immediate vicinity (1250 km2) is estimated to be 132 mm (range, 73-197 mm). Outflow from the unconfined flood-plain aquifer to the unconfined upland aquifer is approximately 10% of the wet-season flood-plain recharge. The unconfined groundwater outflow from the flood-plain area can provide a significant contribution to the present-day rural water supply in the surrounding uplands, but it does not offer much potential for additional groundwater abstraction. In addition to outflow to the upland aquifer (˜14 mm), the distribution of the annually recharged water volume of the shallow flood-plain aquifer is (1) domestic uses (3 mm), (2) small-scale irrigation (˜15 mm), and (3) evapotranspiration ( 1 100 mm). Along the hydrogeologic profile, the recharge in the upland (i.e., outflow from the unconfined flood-plain aquifer and possibly diffuse rain-fed recharge) is in balance with the water uses (i.e., domestic uses, groundwater outflow, and evapotranspiration). The absence of a seasonal water-level trend in the two piezometers in the

  12. Groundwater uptake of forest and agricultural land covers in regions of recharge and discharge

    Directory of Open Access Journals (Sweden)

    Móricz N

    2016-10-01

    Full Text Available Groundwater uptake of vegetation in discharge regions is known to play an important role, e.g., in the Hungarian Great Plain. Nevertheless, only little detailed monitoring of water table fluctuations and groundwater uptake (ETgw were reported under varying hydrologic conditions and vegetation cover. In this study, results of water table monitoring under forest plantations and adjacent corn plots in discharge and recharge regions were analyzed to gain better understanding of the relation of vegetation cover to groundwater uptake. A poplar (Populus tremula plantation and adjacent corn field plot were surveyed in a local discharge area, while a black locust (Robinia pseudoacacia plantation and adjacent corn field plot were analyzed in a recharge area. The water table under the poplar plantation displayed a night-time recovery in the discharge region, indicating significant groundwater supply. In this case an empirical version of the water table fluctuation method was used for calculating the ETgw that included the groundwater supply. The mean ETgw of the poplar plantation was 3.6 mm day-1, whereas no water table fluctuation was observed at the nearby corn plot. Naturally, the root system of the poplar was able to tap the groundwater in depths of 3.0-3.3 m while the shallower roots of the corn did not reach the groundwater reservoir in depths of 2.7-2.8 m. In the recharge zone the water table under the black locust plantation showed step-like changes referring to the lack of groundwater supply. The mean ETgw was 0.7 mm day-1 (groundwater depths of 3.0-3.2 m and similarly no ETgw was detected at the adjacent corn plot with groundwater depths between 3.2 and 3.4 m. The low ETgw of the young black locust plantation was due to the lack of groundwater supply in recharge area, but also the shallow root system might have played a role. Our results suggest that considerations should be given to local estimations of ETgw from water table measurements that

  13. Groundwater ages, recharge conditions and hydrochemical evolution of a barrier island freshwater lens (Spiekeroog, Northern Germany)

    OpenAIRE

    Roeper, T; K. F. Kroeger; Meyer, Hanno; Sueltenfuss, J.; Greskowiak, J.; Massmann, G

    2012-01-01

    Freshwater lenses below barrier islands are dynamic systems affected by changes in morphodynamic patterns, groundwater recharge and discharge. They are also vulnerable to pollution and overabstraction of groundwater. Basic knowledge on hydrogeological and hydrochemical processes of freshwater lenses is important to ensure a sustainable water management, especially when taking into account possible effects of climate change. This is the first study which gives a compact overview on...

  14. Analysis of subsurface temperature data to quantify groundwater recharge rates in a closed Altiplano basin, northern Chile

    Science.gov (United States)

    Kikuchi, C. P.; Ferré, T. P. A.

    2016-09-01

    Quantifying groundwater recharge is a fundamental part of groundwater resource assessment and management, and is requisite to determining the safe yield of an aquifer. Natural groundwater recharge in arid and semi-arid regions comprises several mechanisms: in-place, mountain-front, and mountain-block recharge. A field study was undertaken in a high-plain basin in the Altiplano region of northern Chile to quantify the magnitude of in-place and mountain-front recharge. Water fluxes corresponding to both recharge mechanisms were calculated using heat as a natural tracer. To quantify in-place recharge, time-series temperature data in cased boreholes were collected, and the annual fluctuation at multiple depths analyzed to infer the water flux through the unsaturated zone. To quantify mountain-front recharge, time-series temperature data were collected in perennial and ephemeral stream channels. Streambed thermographs were analyzed to determine the onset and duration of flow in ephemeral channels, and the vertical water fluxes into both perennial and ephemeral channels. The point flux estimates in streambeds and the unsaturated zone were upscaled to channel and basin-floor areas to provide comparative estimates of the range of volumetric recharge rates corresponding to each recharge mechanism. The results of this study show that mountain-front recharge is substantially more important than in-place recharge in this basin. The results further demonstrate the worth of time-series subsurface temperature data to characterize both in-place and mountain-front recharge processes.

  15. Estimating Groundwater Recharge in the Semiarid Al-Khazir Gomal Basin, North Iraq

    Directory of Open Access Journals (Sweden)

    Hussein Jassas

    2014-08-01

    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.

  16. Gas transport below artificial recharge ponds: insights from dissolved noble gases and a dual gas (SF6 and 3He) tracer experiment.

    Science.gov (United States)

    Clark, Jordan F; Hudson, G Bryant; Avisar, Dror

    2005-06-01

    A dual gas tracer experiment using sulfur hexafluoride (SF6) and an isotope of helium (3He) and measurements of dissolved noble gases was performed at the El Rio spreading grounds to examine gas transport and trapped air below an artificial recharge pond with a very high recharge rate (approximately 4 m day(-1)). Noble gas concentrations in the groundwater were greater than in surface water due to excess air formation showing that trapped air exists below the pond. Breakthrough curves of SF6 and 3He at two nearby production wells were very similar and suggest that nonequilibrium gas transfer was occurring between the percolating water and the trapped air. At one well screened between 50 and 90 m below ground, both tracers were detected after 5 days and reached a maximum at approximately 24 days. Despite the potential dilution caused by mixing within the production well, the maximum concentration was approximately 25% of the mean pond concentration. More than 50% of the SF6 recharged was recovered by the production wells during the 18 month long experiment. Our results demonstrate that at artificial recharge sites with high infiltration rates and moderately deep water tables, transport times between recharge locations and wells determined with gas tracer experiments are reliable. PMID:15984768

  17. Groundwater Recharge Estimation using Low-Cost Observation Techniques and Potential Applications

    Science.gov (United States)

    Holländer, Hartmut; Wang, Zijian; Assefa, Kibreab; Woodbury, Allan

    2016-04-01

    Sustainable groundwater management requests groundwater recharge estimation as a critical quantity. We used physical-based modelling using data from a low-cost weather station and tested the feasibility and robustness of recharge estimation. The method was tested on two locations in British Columbia (B.C.), Canada. The main study was conducted in Southern Abbotsford, B.C. and applications related to water management in future climates and to water usage optimization were conducted in Okanagan Valley, B.C. Recharge was determined using HYDRUS-1D. The meteorological data were recorded by a HOBO weather station for a short observation period (about 1 year) and an existing weather station (Abbotsford A) for long-term study purpose (27 years). The derived soil hydraulic parameters of two undisturbed soil cores were used to characterize the soil. Model performance was evaluated by using observed soil moisture and soil temperature data. A rigorous sensitivity analysis was used to test the robustness of the model. Recharge during the short observation period was estimated at 863 mm and 816 mm. The mean annual recharge was estimated at 848 mm/year, and 859 mm/year based on a time series of 27 years. 80% of precipitation contributed to recharge in hydrologic winter period. The comparison of the recharge estimates with other studies indicates a good agreement. Being able to predict transient recharge estimates, this method can provide a tool for estimates on nutrient leaching which is often controlled by strong precipitation events and rapid infiltration of water and nitrate into the soil. Modeling supports that recharge estimates at high temporal resolution also increase the prediction quality of nitrate leaching. The application for water resources related problems in the Okanagan Valley showed that linking groundwater and surface water using regional groundwater estimates improved calibration of existing groundwater model strongly and that our method is capable to use

  18. Groundwater Recharge Evaluation in Semi-Arid Northeast Mexico in Response to Projected Climate Change

    Science.gov (United States)

    Wolaver, B. D.

    2007-12-01

    This research evaluates the effects of projected climate change on mountain recharge in the semi-arid Cuatrocinegas Basin (CCB) of northeast Mexico. The CCB UNESCO Biosphere Reserve is located in Coahuila, Mexico (~27° N, ~102° W) and includes > 500 springs that discharge from a regional flow system to wetlands with > 70 endemic species and to an irrigation network. This study tests the hypothesis that projected climate changes will reduce CCB recharge. In CCB, ~75% of annual precipitation (~220 mm at 700 m, ~400 mm at 2350 m) falls between May and October and ~40% falls during the North American Monsoon in June, July, and August. Environmental isotopes indicate aquifer residence times of > 50 years. Stable isotopes (O and H) show that mountain precipitation (at an elevation of ~1170 to 2350 m) dominates groundwater recharge. Recharge is insignificant at lower- elevation valleys that cover the majority of the study area due to high evapotranspiration rates. A Cl--balance water-budget recharge analysis estimates a spatially distributed recharge rate of ~1 to 3% of precipitation to provide at least 35x106 m3/year spring discharge (as measured in canals that drain dozens of springs). IPCC AR4 climate projections predict an annual temperature increase of 3.0 to 3.5°C and an annual precipitation decrease of 5 to 10% for Subregion CNA (located adjacent to CCB) by 2099. During June to August, models project a temperature increase of 3.5 to 4.0°C and a precipitation increase of 0 to 5%. Although global and regional circulation models evaluate mountain regions poorly, a first-order evaluation of climate projections on CCB recharge is needed input to develop effective long-term groundwater management policies. Climate projections suggest that the minimum elevation at which recharge occurs in CCB may increase by ~615 m to 1785 m, which would limit recharge to the highest mountain elevations. If annual precipitation is reduced by 5 to 10% and temperatures increase as

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

    Science.gov (United States)

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

    2016-05-01

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

  20. Hydrodynamic analysis of the artificial recharge of aquifers during the planning stage. Results obtained in the Quaternary aquifer in the Valley of the Guadalquivir (Spain); Analisis hidrodinamico de la recarga artificial de acuiferos durante la etapa de planificacion. Resultados obtenidos en el acuifero cuaternario del valle del Guadalquivir (Espana)

    Energy Technology Data Exchange (ETDEWEB)

    Murillo, J. M.

    2014-10-01

    This paper shows a study on the viability of an artificial recharge in the flood-plain aquifer of the Guadalquivir River (Andalucia, Spain). The method used to the evaluation of the artificial recharge project is as follows: A simple model (one cell). The code has been made on the use of an EXCEL spreadsheet. A distributed parameters-flow model using a standard code (Modflow). A pilot recharge plant. The simple model has been applied in different zones. The model has only 5 parameters. It evaluates the artificial recharge by means of the depletion coefficient. The model was calibrated for a monthly time-step, although the water balances in the soil and in the aquifer were calculated daily. The calibration the distributed parameter-flow model shows a high transmissivity, storage coefficient and porosity. The pilot recharge plant is a trench with recharge wells within it. The water available for recharge is obtained from an irrigation canal. A network of control points has been established to monitor the piezometric levels. The results obtained show a high storage coefficient and porosity. These parameters show a rapid groundwater velocity. Finally, the paper compares and contrasts the results obtained with the simple model, distributed parameter- flow model and the pilot recharge plant. The results are quite similar. The groundwater velocity is rapid. Water remains in the aquifer for a few days before returning to the river. (Author)

  1. Comparing groundwater recharge and base flow in the Bukmoongol small-forested watershed, Korea

    Indian Academy of Sciences (India)

    E A Combalicer; S H Lee; S Ahn; D Y Kim; S Im

    2008-10-01

    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 the measured stream flow.Results show that about 15 –31 per cent of annual rainfall might be contributed for base flow.The watershed groundwater recharge proportions are computed to about 10 –21 per cent during the wet period and 23 –32 per cent for the remainder periods.Mean annual base flow indices vary from 0.25 to 0.76 estimated using different methods. However,the study found out that all methods were significantly correlated with each other.The similarity of various methods is expressed as a weighted relationship provided by the matrix product from the principal component analysis.Overall,the BFI and WHAT software appeared consistent in estimating recharge or base flow,and base flow index under Korea ’s conditions.The case study recommends the application of different models to other watersheds as well as in low-lying areas where most observation groundwater wells are located with available stream flow data.

  2. A water-budget model and estimates of groundwater recharge for Guam

    Science.gov (United States)

    Johnson, Adam G.

    2012-01-01

    On Guam, demand for groundwater tripled from the early 1970s to 2010. The demand for groundwater is anticipated to further increase in the near future because of population growth and a proposed military relocation to Guam. Uncertainty regarding the availability of groundwater resources to support the increased demand has prompted an investigation of groundwater recharge on Guam using the most current data and accepted methods. For this investigation, a daily water-budget model was developed and used to estimate mean recharge for various land-cover and rainfall conditions. Recharge was also estimated for part of the island using the chloride mass-balance method. Using the daily water-budget model, estimated mean annual recharge on Guam is 394.1 million gallons per day, which is 39 percent of mean annual rainfall (999.0 million gallons per day). Although minor in comparison to rainfall on the island, water inflows from water-main leakage, septic-system leachate, and stormwater runoff may be several times greater than rainfall at areas that receive these inflows. Recharge is highest in areas that are underlain by limestone, where recharge is typically between 40 and 60 percent of total water inflow. Recharge is relatively high in areas that receive stormwater runoff from storm-drain systems, but is relatively low in urbanized areas where stormwater runoff is routed to the ocean or to other areas. In most of the volcanic uplands in southern Guam where runoff is substantial, recharge is less than 30 percent of total water inflow. The water-budget model in this study differs from all previous water-budget investigations on Guam by directly accounting for canopy evaporation in forested areas, quantifying the evapotranspiration rate of each land-cover type, and accounting for evaporation from impervious areas. For the northern groundwater subbasins defined in Camp, Dresser & McKee Inc. (1982), mean annual baseline recharge computed in this study is 159.1 million gallons

  3. Determining the groundwater potential recharge zone and karst springs catchment area: Saldoran region, western Iran

    Science.gov (United States)

    Karami, Gholam Hossein; Bagheri, Rahim; Rahimi, Fahimeh

    2016-08-01

    Assessing the groundwater recharge potential zone and differentiation of the spring catchment area are extremely important to effective management of groundwater systems and protection of water quality. The study area is located in the Saldoran karstic region, western Iran. It is characterized by a high rate of precipitation and recharge via highly permeable fractured karstic formations. Pire-Ghar, Sarabe-Babaheydar and Baghe-rostam are three major karstic springs which drain the Saldoran anticline. The mean discharge rate and electrical conductivity values for these springs were 3, 1.9 and 0.98 m3/s, and 475, 438 and 347 μS/cm, respectively. Geology, hydrogeology and geographical information system (GIS) methods were used to define the catchment areas of the major karstic springs and to map recharge zones in the Saldoran anticline. Seven major influencing factors on groundwater recharge rates (lithology, slope value and aspect, drainage, precipitation, fracture density and karstic domains) were integrated using GIS. Geology maps and field verification were used to determine the weights of factors. The final map was produced to reveal major zones of recharge potential. More than 80 % of the study area is terrain that has a recharge rate of 55-70 % (average 63 %). Evaluating the water budget of Saldoran Mountain showed that the total volume of karst water emerging from the Saldoran karst springs is equal to the total annual recharge on the anticline. Therefore, based on the geological and hydrogeological investigations, the catchment area of the mentioned karst springs includes the whole Saldoran anticline.

  4. Evolution of Redox Conditions and Groundwater Composition in Recharge-Discharge Environments on the Canadian Shield

    Science.gov (United States)

    Gascoyne, M.

    1997-03-01

    The composition of groundwater in fractured crystalline rocks of the Canadian Shield evolves along flow paths from recharge to discharge in response to interactions with bedrock and fracture-filling minerals, and by dissolution of soluble (Cl-rich) salts in the rock matrix. The groundwater redox potential changes from oxidizing to reducing conditions due, initially, to rapid consumption of dissolved oxygen by organics in the upper ˜100 m of bedrock and, subsequently, to interaction with rock minerals. Measured Eh values of deep groundwater in the granitic Lac du Bonnet batholith in southeastern Manitoba indicate that the Fe(II)/Fe(III) couple controls groundwater redox potential. This conclusion is supported by other geochemical characteristics, such as absence of CH4, H2S, H2, NO3 and abundance of SO4. These observations are important in selecting a suitable site for disposal of nuclear fuel wastes. Further evidence of the evolution of redox conditions is given by variations in uranium concentration, which range from about 1,000μg/L in dilute near-surface groundwater to <1 μg/L in some deep, saline groundwaters. Groundwater at about 400 m depth in a recharge area on the Lac du Bonnet batholith contains significantly more uranium than groundwater farther along the flow path or near-surface in discharge areas. Uranium concentration is a useful and sensitive indicator of redox conditions.

  5. Impact of climate change on groundwater recharge in dry areas: An ecohydrology approach

    Science.gov (United States)

    Liu, Hui-Hai

    2011-09-01

    SummaryThis work proposes an ecohydrology-based approach to study the impact of climate change on groundwater recharge in dry areas. It is largely based on a concept that in dry areas, vegetation community can be divided into two different groups, shallow- and deep-rooted vegetation, with the growing-season average of root-zone soil water saturation tending to be at its optimum value for the growth of deep-rooted vegetation. The concept is supported by data sets collected from different dry areas. Analytical results of soil water dynamics developed in previous studies are adapted here for investigating the impact of climate change. Because the conceptual model allows deep-zone soil-water saturation, averaged over growing seasons, to remain fixed during different climate conditions, we can construct a relationship among groundwater recharge, the coverage of deep-rooted vegetation, and climate. As an illustrative example, we apply the developed approach to the Yucca Mountain area. Our estimated recharge value under the current climate and the vegetation coverage is generally consistent with results estimated from other methods or observed from the site. We also evaluate how the recharge will change under several assumed future climate scenarios. The results show that both groundwater recharge and deep-rooted vegetation coverage increase with decreasing rainfall frequency (for a given amount of annual rainfall), with increasing average rainfall depth per rainfall event (for a fixed frequency) and with increasing frequency (for a fixed rainfall depth per rainfall event). The latter indicates a relatively large degree of buffering effects of vegetation on changes in groundwater recharge.

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

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2016-02-01

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

  7. Groundwater recharge in a semi-arid environment under high climatic variability and over-pumping: Ajlun Highlands example, Jordan.

    Science.gov (United States)

    Raggad, Marwan; Salameh, Elias; Magri, Fabien; Siebert, Christian; Roediger, Tino; Moller, Peter

    2016-04-01

    Jordan's ground water resources are being exploited up to 190% of the safe yield while rainfall rates are decreasing and highly variable, thereby affecting recharge volumes of the aquifers. The Ajlun highlands, forming the northwestern edge of Jordan are characterized by annual rainfall rates exceeding 500 mm, the highest in the country, which leads to accordingly high replenishment of almost the entire groundwater system in northern Jordan. The high recharge and the NW-wards dipping strata lead to a groundwater flow towards the north and northwest, areas which host the vital aquifers of the region. Limited and degraded groundwater recharge combined with growing over-pumping are the main issues that regard the northern groundwater basins, such as Wadi Arab, Yarmouk and the Jordan Valley side basins. To evaluate the groundwater potential under high recharge variability, groundwater recharge was modeled and compared to different Global Circulation Models (GCMs). Groundwater recharge was calculated based on climatic data covering the time period from 1965 to 2014. Recharge modeling was conducted by applying the J2000 water budget model. The simulation of hydrologic processes uses independent parameters that are calculated prior to simulate the recharge flow. The simulations estimate recharge of 47.6 MCM, which is 12% less than the values given by the Jordanian authorities. The low calculated recharge is likely due to an overestimation of the evapotranspiration in areas with high topographic slopes. To examine the variability of groundwater recharge under current climatic conditions, statistical downscaling of global circulation models was conducted for the time period 1965 - 2000. Data for the time period 2001 - 2014 was used for the model validation. Results indicated a decline of 18.7% in precipitation by the year 2050 with an increase of 1.7 and 2.2 degrees in maximum and minimum temperatures respectively. Accordingly recharge for the year 2050 is 27% less than

  8. Natural groundwater recharge and water balance at the Hanford Site

    International Nuclear Information System (INIS)

    The purpose of this report is to present water-balance data collected in 1988 and 1989 from the 300 Area Buried Waste Test Facility and Grass Site, and the 200 East Area closed-bottom lysimeter. This report is an annual update of previous recharge status reports by Gee, Rockhold, and Downs, and Gee. Data from several other lysimeter sites are included for comparison. 43 refs., 28 figs., 7 tabs

  9. Fens as Whole-Ecosystem Gauges of Groundwater Recharge Under Climate Change

    Science.gov (United States)

    Drexler, J. Z.; Knifong, D. L.; Tuil, J.; Flint, L. E.; Flint, A. L.

    2011-12-01

    Over the past century, mean air temperature has increased approximately 1 C in California. Since the 1950s, there has been an earlier onset of snowmelt and reduced snowpack (measured as snow water equivalent) in California as well as in much of the western United States. Because the snowpack is the main source of groundwater recharge in the mountainous west, reduced snowpack could result in decreased groundwater recharge through time. This could have important ramifications because groundwater recharge maintains groundwater springs, soil moisture, river baseflows and cool water temperatures. Reductions in groundwater recharge could not only impact water availability for human populations, but could also threaten long-term viability of ecosystems reliant on groundwater flows. Groundwater-fed peatlands called fens are potentially ideal ecosystems for studying changes in groundwater recharge, because they are groundwater discharge sites that rely upon corresponding recharge sites for their sustenance. When the amount of groundwater flow to a fen is reduced, the elevation of the water table decreases leading to desiccation, compaction and increased microbial oxidation of the organic soil. In cases where groundwater flow is reduced over an extended period of time, conversion of fen into wet or mesic meadow or even pine forest can occur resulting in contraction of fen boundaries. The purpose of this study is to evaluate the usefulness of fens as whole-ecosystem gauges of groundwater recharge. We studied 7 fens distributed throughout the Sierra Nevada by tracking their areas over 70+ years with aerial photography. All photos were geo-registered using the 2005 National Agricultural Inventory Program orthophotography as the base. Images were projected to UTM zone 10, NAD 83 using ArcGIS 10.0. Fen vegetation was identified in the aerial photos predominantly by (1) dark brownish-green coloring (or various shades of gray and black in black and white imagery) and (2) mottling

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-09-15

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

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

    International Nuclear Information System (INIS)

    Geochemical and environmental isotope data were used to gain the first regional picture of groundwater recharge, circulation and its hydrochemical evolution in the upper Blue Nile River basin of Ethiopia. Q-mode statistical cluster analysis (HCA) was used to classify water into objective groups and to conduct inverse geochemical modeling among the groups. Two major structurally deformed regions with distinct groundwater circulation and evolution history were identified. These are the Lake Tana Graben (LTG) and the Yerer Tullu Wellel Volcanic Lineament Zone (YTVL). Silicate hydrolysis accompanied by CO2 influx from deeper sources plays a major role in groundwater chemical evolution of the high TDS Na-HCO 3 type thermal groundwaters of these two regions. In the basaltic plateau outside these two zones, groundwater recharge takes place rapidly through fractured basalts, groundwater flow paths are short and they are characterized by low TDS and are Ca-Mg-HCO 3 type waters. Despite the high altitude (mean altitude ∼2500 masl) and the relatively low mean annual air temperature (18 deg. C) of the region compared to Sahelian Africa, there is no commensurate depletion in δ 18O compositions of groundwaters of the Ethiopian Plateau. Generally the highland areas north and east of the basin are characterized by relatively depleted δ 18O groundwaters. Altitudinal depletion of δ 18O is 0.1%o/100 m. The meteoric waters of the Blue Nile River basin have higher d-excess compared to the meteoric waters of the Ethiopian Rift and that of its White Nile sister basin which emerges from the equatorial lakes region. The geochemically evolved groundwaters of the YTVL and LTG are relatively isotopically depleted when compared to the present day meteoric waters reflecting recharge under colder climate and their high altitude

  12. Groundwater recharge environments and hydrogeochemical evolution in the Jiuquan Basin, Northwest China

    International Nuclear Information System (INIS)

    The groundwater recharge environments and hydrogeochemical characteristics in the Quaternary aquifer of Jiuquan Basin was investigated using a combination of chemical indicators, stable isotopes, and radiocarbon dating. The d-excess values of winter precipitation and surface water revealed that the meltwater from snow and ice played the dominant role in the basin’s surface water supply. The unconfined groundwater showed gradual enrichment of heavy isotopes along the flow path, but δ18O and δ2H values were similar to those of surface water, suggesting recent recharge as a result of rapid seepage along rivers combined with the effects of high evaporation. The 14C (pmc) values of unconfined groundwater was between 71.5% and 90.9%, and since 80% modern carbon probably represents the upper limit of initial 14C activity, this suggests that the groundwater is relatively young. The confined groundwater was depleted in heavy isotopes; coupled with low 14C values (∼20–53%), indicating that the groundwater was mainly recharged as palaeowater during the late Pleistocene and Holocene epochs under a cold climate. The surface water and most groundwater samples were fresh rather than saline, with TDS −1, respectively. The chemistry of unconfined groundwater changed from HCO3-dominated to no dominant ions and then to SO42-dominated moving along the flow path from the Jiuquan-Jiayuguan Basin to the Jinta Basin, and the confined water was SO42-dominated. The results have important implications for groundwater management in the Basin, where a high proportion of the water being used is in effect being mined (i.e., extracted faster than its replacement rate); thus, significant changes are urgently needed in the regional water-use strategy.

  13. Geochemical Effects of Induced Stream-Water and Artificial Recharge on the Equus Beds Aquifer, South-Central Kansas, 1995-2004

    Science.gov (United States)

    Schmidt, Heather C. Ross; Ziegler, Andrew C.; Parkhurst, David L.

    2007-01-01

    Artificial recharge of the Equus Beds aquifer is part of a strategy implemented by the city of Wichita, Kansas, to preserve future water supply and address declining water levels in the aquifer of as much as 30 feet caused by withdrawals for water supply and irrigation since the 1940s. Water-level declines represent a diminished water supply and also may accelerate migration of saltwater from the Burrton oil field to the northwest and the Arkansas River to the southwest into the freshwater of the Equus Beds aquifer. Artificial recharge, as a part of the Equus Beds Ground-Water Recharge Project, involves capturing flows larger than base flow from the Little Arkansas River and recharging the water to the Equus Beds aquifer by means of infiltration or injection. The geochemical effects on the Equus Beds aquifer of induced stream-water and artificial recharge at the Halstead and Sedgwick sites were determined through collection and analysis of hydrologic and water-quality data and the application of statistical, mixing, flow and solute-transport, and geochemical model simulations. Chloride and atrazine concentrations in the Little Arkansas River and arsenic concentrations in ground water at the Halstead recharge site frequently exceeded regulatory criteria. During 30 percent of the time from 1999 through 2004, continuous estimated chloride concentrations in the Little Arkansas River at Highway 50 near Halstead exceeded the Secondary Drinking-Water Regulation of 250 milligrams per liter established by the U.S. Environmental Protection Agency. Chloride concentrations in shallow monitoring wells located adjacent to the stream exceeded the drinking-water criterion five times from 1995 through 2004. Atrazine concentrations in water sampled from the Little Arkansas River had large variability and were at or near the drinking-water Maximum Contaminant Level of 3.0 micrograms per liter as an annual average established by the U.S. Environmental Protection Agency. Atrazine

  14. Labile Organic Carbon in Recharge and its Impact on Groundwater Arsenic Concentrations in Bangladesh

    Science.gov (United States)

    Neumann, R. B.; Ashfaque, K. N.; Badruzzaman, A. M.; Ali, M.; Shoemaker, J. K.; Harvey, C. F.

    2009-12-01

    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.

  15. Partitioning groundwater recharge between rainfall infiltration and irrigation return flows using stable isotopes: the Crau aquifer.

    Science.gov (United States)

    Seraphin, Pierre; Vallet-Coulomb, Christine; Gonçalvès, Julio

    2016-04-01

    Traditional flood irrigation is used since the 16th century in the Crau plain (Southern France) for hay production. To supply this high consuming irrigation practice, water is diverted from the Durance River, originating from the Alps, and the large amount of irrigation return flows constitutes the main recharge of the Crau aquifer, which is in turn largely exploited for domestic, industrial and agricultural water use. A possible reduction of irrigation fluxes due to a need of water saving or to a future land-use change could endanger the groundwater resource. A robust quantification of the groundwater mass balance is thus required to assess a sustainable water management in the region. The high isotopic contrast between these exogenous irrigation waters and local precipitations allows the use of stable isotopes of water as conservative tracers to deduce their contributions to the surface recharge. An extensive groundwater sampling was performed to obtain δ18O and δ2H over the whole aquifer. Based on a new piezometric contour map, combined with a reestimate of the aquifer geometry, the isotopic data are implemented in a geostatistical approach to produce a conceptual equivalent-homogeneous reservoir, in order to apply a simple water and isotope mass balance mixing model. The isotopic composition of the two end-members is assessed, and the quantification of groundwater flows is then used to calculate the two recharge fluxes. Near to steady-state condition, the set of isotopic data treated by geostatistics leads to a recharge by irrigation of 5.20 ± 0.93 m3 s-1 i.e. 1173 ± 210 mm yr-1, and a natural recharge of 2.26 ± 0.91 m3 s-1 i.e. 132 ± 53 mm yr-1. Thus, 70 ± 9% of the effective surface recharge comes from the irrigation return flow, consistent with the literature (between 67% and 78%). This study constitutes a straightforward and independent approach to assess groundwater surface recharges with uncertainties and will help to constrain a future transient

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

    Science.gov (United States)

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

    2016-01-01

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

  17. Effects of acidic recharge on groundwater at the St. Kevin Gulch site, Leadville, Colorado

    Science.gov (United States)

    Paschke, S.S.; Harrison, W.J.; Walton-Day, K.

    2001-01-01

    The acid rock drainage-affected stream of St. Kevin Gulch recharges the Quaternary sand and gravel aquifer of Tennessee Park, near Leadville, Colorado, lowering pH and contributing iron, cadmium, copper, zinc and sulphate to the ground-water system. Dissolved metal mobility is controlled by the seasonal spring runoff as well as oxidation/reduction (redox) reactions in the aquifer. Oxidizing conditions occur in the unconfined portions of the aquifer whilst sulphate-reducing conditions are found down gradient where semi-confined groundwater flow occurs beneath a natural wetland. Iron-reducing conditions occur in the transition from unconfined to semi-confined groundwater flow. Dissolved iron concentrations are low to not detectable in the alluvial fan recharge zone and increase in a down gradient direction. The effects of low-pH, metal-rich recharge are pronounced during low-flow in the fall when there is a defined area of low pH groundwater with elevated concentrations of dissolved zinc, cadmium, copper and sulphate adjacent to St. Kevin Gulch. Dissolved metal and sulphate concentrations in the recharge zone are diluted during spring runoff, although the maximum concentrations of dissolved zinc, cadmium, copper and sulphate occur at selected down gradient locations during high flow. Dissolved zinc, cadmium and copper concentrations are low to not detectable, whereas dissolved iron concentrations are greatest, in groundwater samples from the sulphate-reducing zone. Attenuation of zinc, cadmium and copper beneath the wetland suggests sulphide mineral precipitation is occurring in the semi-confined aquifer, in agreement with previous site investigations and saturation index calculations. Adsorption of dissolved zinc, cadmium and copper onto iron hydroxides is a minor attenuation process due to the low pH of the groundwater system.

  18. Estimating annual groundwater recharge coefficient for karst aquifers of the southern Apennines (Italy)

    Science.gov (United States)

    Allocca, V.; Manna, F.; De Vita, P.

    2014-02-01

    To assess the mean annual groundwater recharge of the karst aquifers in the southern Apennines (Italy), the estimation of the mean annual groundwater recharge coefficient (AGRC) was conducted by means of an integrated approach based on hydrogeological, hydrological, geomorphological, land use and soil cover analyses. Starting from the hydrological budget equation, the coefficient was conceived as the ratio between the net groundwater outflow and the precipitation minus actual evapotranspiration (P - ETR) for a karst aquifer. A large part of the southern Apennines, which is covered by a meteorological network containing 40 principal karst aquifers, was studied. Using precipitation and air temperature time series gathered through monitoring stations operating in the period 1926-2012, the mean annual P - ETR was estimated, and its distribution was modelled at a regional scale by considering the orographic barrier and rain shadow effects of the Apennine chain, as well as the altitudinal control. Four sample karst aquifers with available long spring discharge time series were identified for estimating the AGRC. The resulting values were correlated with other parameters that control groundwater recharge, such as the extension of outcropping karst rocks, morphological settings, land use and covering soil type. A multiple linear regression between the AGRC, lithology and the summit plateau and endorheic areas was found. This empirical model was used to assess the AGRC and mean annual groundwater recharge in other regional karst aquifers. The coefficient was calculated as ranging between 50 and 79%, thus being comparable with other similar estimations carried out for karst aquifers of European and Mediterranean countries. The mean annual groundwater recharge for karst aquifers of the southern Apennines was assessed by these characterizations and validated by a comparison with available groundwater outflow measurements. These results represent a deeper understanding of an

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

    Science.gov (United States)

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

    2007-12-01

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

  20. A screening tool for delineating subregions of steady recharge within groundwater models

    Science.gov (United States)

    Dickinson, Jesse E.; Ferré, T. P. A.; Bakker, Mark; Crompton, Becky

    2014-01-01

    We have developed a screening method for simplifying groundwater models by delineating areas within the domain that can be represented using steady-state groundwater recharge. The screening method is based on an analytical solution for the damping of sinusoidal infiltration variations in homogeneous soils in the vadose zone. The damping depth is defined as the depth at which the flux variation damps to 5% of the variation at the land surface. Groundwater recharge may be considered steady where the damping depth is above the depth of the water table. The analytical solution approximates the vadose zone diffusivity as constant, and we evaluated when this approximation is reasonable. We evaluated the analytical solution through comparison of the damping depth computed by the analytic solution with the damping depth simulated by a numerical model that allows variable diffusivity. This comparison showed that the screening method conservatively identifies areas of steady recharge and is more accurate when water content and diffusivity are nearly constant. Nomograms of the damping factor (the ratio of the flux amplitude at any depth to the amplitude at the land surface) and the damping depth were constructed for clay and sand for periodic variations between 1 and 365 d and flux means and amplitudes from nearly 0 to 1 × 10−3 m d−1. We applied the screening tool to Central Valley, California, to identify areas of steady recharge. A MATLAB script was developed to compute the damping factor for any soil and any sinusoidal flux variation.

  1. Feasibility of groundwater recharge dam projects in arid environments

    Science.gov (United States)

    Jaafar, H. H.

    2014-05-01

    A new method for determining feasibility and prioritizing investments for agricultural and domestic recharge dams in arid regions is developed and presented. The method is based on identifying the factors affecting the decision making process and evaluating these factors, followed by determining the indices in a GIS-aided environment. Evaluated parameters include results from field surveys and site visits, land cover and soils data, precipitation data, runoff data and modeling, number of beneficiaries, domestic irrigation demand, reservoir objectives, demography, reservoirs yield and reliability, dam structures, construction costs, and operation and maintenance costs. Results of a case study on more than eighty proposed dams indicate that assessment of reliability, annualized cost/demand satisfied and yield is crucial prior to investment decision making in arid areas. Irrigation demand is the major influencing parameter on yield and reliability of recharge dams, even when only 3 months of the demand were included. Reliability of the proposed reservoirs as related to their standardized size and net inflow was found to increase with increasing yield. High priority dams were less than 4% of the total, and less priority dams amounted to 23%, with the remaining found to be not feasible. The results of this methodology and its application has proved effective in guiding stakeholders for defining most favorable sites for preliminary and detailed design studies and commissioning.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

  3. A review of groundwater recharge estimation in humid and semi-arid African regions

    Science.gov (United States)

    Chung, Il-Moon; Kim, Nam Won

    2016-04-01

    For the review of African recharge estimation, the distinct methods such as the geochemical approach, a method using groundwater level data, the streamflow method, and the water balance methods were first outlined. The major challenge of an African recharge study is the lack of basic data. Thus, this work suggests how to deal with this limitation and from future perspective using recently developed technologies such as RS, GIS, etc. With the rapid growth of information technology, more and more data, in terms of both volume and variety, are expected to be made available on the internet in the near future. RS technology has a great potential to revolutionize the groundwater development and management in the future by providing unique and completely new hydrological and hydrogeological data. However, at present, the RS data should be considered along with the conventional field data. In spite of the weaknesses of water balance methods in semi-arid areas, recently developed water balance methods combined with GIS technology are powerful tools for estimating groundwater re-charge, when spatial-temporal variability of components in water balance is taken into account (Lerner et al., 1990; De Vries and Simmers, 2002; Eilers et al., 2007).When enough data sets are available, integrated surface-groundwater modeling is recommended for more accurate estimation of groundwater recharge and discharge. Acknowledgements This work was supported by a grant(14RDRP-B076275-01-000000) from Infrastructure and transportation technology promotion research Program funded by the Ministry of Land, Infrastructure and Transport of Korean government.

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

    International Nuclear Information System (INIS)

    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 km2 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 R2 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

  5. B-10 enriched boric acid, bromide, and heat as tracers of recycled groundwater flow near managed aquifer recharge operations

    Science.gov (United States)

    Clark, J. F.; Becker, T.; Johnson, T. A.

    2013-12-01

    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

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

    Directory of Open Access Journals (Sweden)

    W. Dawes

    2012-05-01

    Full Text Available 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 rainfall of between 5 and 15%. There is expected to be a continuing 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 land cover type (e.g. native trees, plantation, cropping, urban, wetland, soil type, and taking into account the groundwater depth. These recharge estimates were accumulated on a daily basis for both observed and projected climate scenarios and used in a MODFLOW simulation with monthly stress periods.

    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 the Dandaragan Plateau to the north-east of Perth there has been groundwater level rise since the 1970s associated with land clearing, and with rainfall projected to reduce the least in this area the groundwater levels are estimated to continue to rise. Along the coastal zone north of Perth there is an interaction between projected rainfall decline and legislated removal to pine forests. This

  7. Infilitration tests at the Sant Vicenç dels Horts artificial recharge experimental site

    OpenAIRE

    Barahona-Palomo, Marco; Pedretti, Daniele; Sánchez Vila, Francisco Javier

    2010-01-01

    Infiltration capacity is the key parameter in an artificial recharge operation site. Infiltration capacity is spatially variable, and during operation it is also temporally variable due to surface clogging processes. Double-ring infiltrometer tests were performed at an experimental site close to Barcelona city (Spain). The site is located on alluvial deposits from the Llobregat River and comprises two half hectare ponds. River water collected upstream traveled through a two km pipe before ent...

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

    Science.gov (United States)

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

    2010-05-01

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

  9. Estimability of recharge through groundwater model calibration: Insights from a field-scale steady-state example

    Science.gov (United States)

    Knowling, Matthew J.; Werner, Adrian D.

    2016-09-01

    The ability of groundwater models to inform recharge through calibration is hampered by the correlation between recharge and aquifer parameters such as hydraulic conductivity (K), and the insufficient information content of observation datasets. These factors collectively result in non-uniqueness of parameter estimates. Previous studies that jointly estimate spatially distributed recharge and hydraulic parameters are limited to synthetic test cases and/or do not evaluate the effect of non-uniqueness. The extent to which recharge can be informed by calibration is largely unknown for practical situations, in which complexities such as parameter heterogeneities are inherent. In this study, a systematic investigation of recharge, inferred through model calibration, is undertaken using a series of numerical experiments that include varying degrees of hydraulic parameter information. The analysis involves the use of a synthetic reality, based on a regional-scale, highly parameterised, steady-state groundwater model of Uley South Basin, South Australia. Parameter identifiability is assessed to evaluate the ability of parameters to be estimated uniquely. Results show that a reasonable inference of recharge (average recharge error 100 K values across the 129 km2 study area). The introduction of pumping data into the calibration reduces error in both the average recharge and its spatial variability, whereas submarine groundwater discharge (as a calibration target) reduces average recharge error only. Nonetheless, the estimation of steady-state recharge through inverse modelling may be impractical for real-world settings, limited by the need for unrealistic amounts of hydraulic parameter and groundwater level data. This study provides a useful benchmark for evaluating the extent to which field-scale groundwater models can be used to inform recharge subject to practical data-availability limitations.

  10. Integrating Raster Based GIS with Land Use, Surface Soil and Rainfall Records for the Estimation of Groundwater Recharge

    Science.gov (United States)

    Yu, C. H.; Chen, Y. W.; Chang, L. C.

    2015-12-01

    In Taiwan, groundwater resource plays a vital role in regional water supply because the quantity of groundwater pumpage has exceeded 1/3 of the total quantity of water supply. However, without proper management of groundwater usage, series environmental impacts such as land subsidence and seawater intrusions have occurred. To achieve the goal of sustainable management of groundwater resource, an accurate estimation of groundwater recharge is required. This study proposes to integrate PCRaster with maps of land use and surface soil and rainfall records to determine the spatial and temporal variations of groundwater recharge. PCRaster is a kind of raster based GIS software and its scripting interface is easy to create a spatio-temporal recharge estimation model. In the first step, the map of land use is re-grouped into three categories, impermeable zones, permeable zones and water bodies. For impermeable zones, the recharge quantities are assumed as zeros. Two kinds of estimating equations, a rainfall-infiltration equation and a saturated recharge equation, are respectively used to calculate the recharges of permeable zones and water bodies. The map of surface soil is used to define the spatial distribution of soil parameters in two equations. The temporal records of rainfall define the temporal variable in the rainfall-infiltration equation. The study area is Pingtung Plain which is 1,229 km2 in southern of Taiwan. In the process of estimation, the size of cells is 20 meters by 20 meters. The horizontal of estimation is during 1999 to 2010. The accumulated recharge is about 20.11 billion m3. (1.67 m3/yr). The annual recharge in 2008 is 1.89 billion m3. The annual recharges vary from 1.3 to 2.1 billion m3 because of different hydrological conditions. The infiltrated recharge in May and November in 2008 respectively are 430 (22.73%) and 67 (3.53%) million m3.

  11. Land cover or climate? In search of dominant factors inducing groundwater recharge and fen hydrology in European scale

    Science.gov (United States)

    Grygoruk, Mateusz; Kotowski, Wiktor

    2016-04-01

    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

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

    Science.gov (United States)

    Narula, Kapil K; Gosain, A K

    2013-12-01

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

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

    Science.gov (United States)

    Narula, Kapil K; Gosain, A K

    2013-12-01

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

  14. Attributes for NHDPlus Catchments (Version 1.1) for the Conterminous United States: Estimated Mean Annual Natural Groundwater Recharge, 2002

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the mean annual natural groundwater recharge, in millimeters, compiled for every catchment of NHDPlus for the conterminous United States....

  15. Factors influencing ground-water recharge in the eastern United States

    Science.gov (United States)

    Nolan, B.T.; Healy, R.W.; Taber, P.E.; Perkins, K.; Hitt, K.J.; Wolock, D.M.

    2007-01-01

    Ground-water recharge estimates for selected locations in the eastern half of the United States were obtained by Darcian and chloride-tracer methods and compared using statistical analyses. Recharge estimates derived from unsaturated-zone (RUZC) and saturated-zone (RSZC) chloride mass balance methods are less variable (interquartile ranges or IQRs are 9.5 and 16.1 cm/yr, respectively) and more strongly correlated with climatic, hydrologic, land use, and sediment variables than Darcian estimates (IQR = 22.8 cm/yr). The unit-gradient Darcian estimates are a nonlinear function of moisture content and also reflect the uncertainty of pedotransfer functions used to estimate hydraulic parameters. Significance level is 0.3. Estimates of RSZC were evaluated using analysis of variance, multiple comparison tests, and an exploratory nonlinear regression (NLR) model. Recharge generally is greater in coastal plain surficial aquifers, fractured crystalline rocks, and carbonate rocks, or in areas with high sand content. Westernmost portions of the study area have low recharge, receive somewhat less precipitation, and contain fine-grained sediment. The NLR model simulates water input to the land surface followed by transport to ground water, depending on factors that either promote or inhibit water infiltration. The model explains a moderate amount of variation in the data set (coefficient of determination = 0.61). Model sensitivity analysis indicates that mean annual runoff, air temperature, and precipitation, and an index of ground-water exfiltration potential most influence estimates of recharge at sampled sites in the region. Soil characteristics and land use have less influence on the recharge estimates, but nonetheless are significant in the NLR model. ?? 2006 Elsevier B.V. All rights reserved.

  16. Long-term spatio-temporal precipitation variability in arid-zone Australia and implications for groundwater recharge

    Science.gov (United States)

    Acworth, R. Ian; Rau, Gabriel C.; Cuthbert, Mark O.; Jensen, Evan; Leggett, Keith

    2016-06-01

    Quantifying dryland groundwater recharge as a function of climate variability is becoming increasingly important in the face of a globally depleted resource, yet this remains a major challenge due to lack of adequate monitoring and the complexity of processes involved. A previously unpublished and unique dataset of high density and frequency rainfall measurements is presented, from the Fowlers Gap Arid Zone Research Station in western New South Wales (Australia). The dataset confirms extreme spatial and temporal variability in rainfall distribution which has been observed in other dryland areas and is generally explained by the dominance of individual storm cells. Contrary to previous observations, however, this dataset contains only a few localised storm cells despite the variability. The implications of spatiotemporal rainfall variability on the estimation of groundwater recharge is assessed and show that the most likely recharge mechanism is through indirect and localised, rather than direct, recharge. Examples of rainfall and stream gauge height illustrate runoff generation when a spatially averaged threshold of 15-25 mm (depending on the antecedent moisture conditions) is exceeded. Preliminary assessment of groundwater levels illustrates that the regional water table is much deeper than anticipated, especially considering the expected magnitude of indirect and localised recharge. A possible explanation is that pathways for indirect and localised recharge are inhibited by the large quantities of Aeolian dust observed at the site. Runoff readily occurs with water collecting in surface lakes which slowly dry and disappear. Assuming direct groundwater recharge under these conditions will significantly overestimate actual recharge.

  17. Application Of Water Table Fluctuation Method To Quantify Spatial Groundwater Recharge Witidn The Southern Slope Of Merapi Volcano, Indonesia

    Directory of Open Access Journals (Sweden)

    Tjahyo Nugroho Adji

    2013-07-01

    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.

  18. Organic micropollutant removal from wastewater effluent-impacted drinking water sources during bank filtration and artificial recharge.

    Science.gov (United States)

    Maeng, Sung Kyu; Ameda, Emmanuel; Sharma, Saroj K; Grützmacher, Gesche; Amy, Gary L

    2010-07-01

    Natural treatment systems such as bank filtration (BF) and artificial recharge (via an infiltration basin) are a robust barrier for many organic micropollutants (OMPs) and may represent a low-cost alternative compared to advanced drinking water treatment systems. This study analyzes a comprehensive database of OMPs at BF and artificial recharge (AR) sites located near Lake Tegel in Berlin (Germany). The focus of the study was on the derivation of correlations between the removal efficiencies of OMPs and key factors influencing the performance of BF and AR. At the BF site, shallow monitoring wells located close to the Lake Tegel source exhibited oxic conditions followed by prolonged anoxic conditions in deep monitoring wells and a production well. At the AR site, oxic conditions prevailed from the recharge pond along monitoring wells to the production well. Long residence times of up to 4.5 months at the BF site reduced the temperature variation during soil passage between summer and winter. The temperature variations were greater at the AR site as a consequence of shorter residence times. Deep monitoring wells and the production well located at the BF site were under the influence of ambient groundwater and old bank filtrate (up to several years of age). Thus, it is important to account for mixing with native groundwater and other sources (e.g., old bank filtrate) when estimating the performance of BF with respect to removal of OMPs. Principal component analysis (PCA) was used to investigate correlations between OMP removals and hydrogeochemical conditions with spatial and temporal parameters (e.g., well distance, residence time and depth) from both sites. Principal component-1 (PC1) embodied redox conditions (oxidation-reduction potential and dissolved oxygen), and principal component-2 (PC2) embodied degradation potential (e.g., total organic carbon and dissolved organic carbon) with the calcium carbonate dissolution potential (Ca(2+) and HCO(3)(-)) for the BF

  19. Organic micropollutant removal from wastewater effluent-impacted drinking water sources during bank filtration and artificial recharge

    KAUST Repository

    Maeng, Sungkyu

    2010-07-01

    Natural treatment systems such as bank filtration (BF) and artificial recharge (via an infiltration basin) are a robust barrier for many organic micropollutants (OMPs) and may represent a low-cost alternative compared to advanced drinking water treatment systems. This study analyzes a comprehensive database of OMPs at BF and artificial recharge (AR) sites located near Lake Tegel in Berlin (Germany). The focus of the study was on the derivation of correlations between the removal efficiencies of OMPs and key factors influencing the performance of BF and AR. At the BF site, shallow monitoring wells located close to the Lake Tegel source exhibited oxic conditions followed by prolonged anoxic conditions in deep monitoring wells and a production well. At the AR site, oxic conditions prevailed from the recharge pond along monitoring wells to the production well. Long residence times of up to 4.5 months at the BF site reduced the temperature variation during soil passage between summer and winter. The temperature variations were greater at the AR site as a consequence of shorter residence times. Deep monitoring wells and the production well located at the BF site were under the influence of ambient groundwater and old bank filtrate (up to several years of age). Thus, it is important to account for mixing with native groundwater and other sources (e.g., old bank filtrate) when estimating the performance of BF with respect to removal of OMPs. Principal component analysis (PCA) was used to investigate correlations between OMP removals and hydrogeochemical conditions with spatial and temporal parameters (e.g., well distance, residence time and depth) from both sites. Principal component-1 (PC1) embodied redox conditions (oxidation-reduction potential and dissolved oxygen), and principal component-2 (PC2) embodied degradation potential (e.g., total organic carbon and dissolved organic carbon) with the calcium carbonate dissolution potential (Ca2+ and HCO3 -) for the BF site

  20. Isotope Method for Confined Groundwater Recharge of the Lower Reaches of the Heihe River, Inner Mongolia, China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Environmental isotopes have been applied to analyze confined groundwater recharge in the lower reaches of the Heihe River, Inner Mongolia. CFC is regarded as a tracer that determines the date of groundwater, the date being less than 45 a. The confined groundwater within the Gurinai area and Ejin Basin other than the surface water of Heihe River might have originated from precipitation from Qilian Mountain or/and the Tibetan Plateau. The deep confined groundwater overflows into an upper aquifer and emerges into the ground, forming springs and lakes within the low-lying area. The recharge volume is estimated to be around 400 million-cubic meters.

  1. Review: Current and emerging methods for catchment-scale modelling of recharge and evapotranspiration from shallow groundwater

    Science.gov (United States)

    Doble, Rebecca C.; Crosbie, Russell S.

    2016-09-01

    A review is provided of the current and emerging methods for modelling catchment-scale recharge and evapotranspiration (ET) in shallow groundwater systems. With increasing availability of data, such as remotely sensed reflectance and land-surface temperature data, it is now possible to model groundwater recharge and ET with more physically realistic complexity and greater levels of confidence. The conceptual representation of recharge and ET in groundwater models is critical in areas with shallow groundwater. The depth dependence of recharge and vegetation water-use feedback requires additional calibration to fluxes as well as heads. Explicit definition of gross recharge vs. net recharge, and groundwater ET vs. unsaturated zone ET, in preparing model inputs and reporting model results is necessary to avoid double accounting in the water balance. Methods for modelling recharge and ET include (1) use of simple surface boundary conditions for groundwater flow models, (2) coupling saturated groundwater models with one-dimensional unsaturated-zone models, and (3) more complex fully-coupled surface-unsaturated-saturated conceptualisations. Model emulation provides a means for including complex model behaviours with lower computational effort. A precise ET surface input is essential for accurate model outputs, and the model conceptualisation depends on the spatial and temporal scales under investigation. Using remote sensing information for recharge and ET inputs in model calibration or in model-data fusion is an area for future research development. Improved use of uncertainty analysis to provide probability bounds for groundwater model outputs, understanding model sensitivity and parameter dependence, and guidance for further field-data acquisition are also areas for future research.

  2. Comparison of groundwater recharge estimation methods for the semi-arid Nyamandhlovu area, Zimbabwe

    OpenAIRE

    Sibanda, T.; Nonner, J.C.; Uhlenbrook, S.

    2009-01-01

    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 recharge estimation methods and results were compared: chloride mass balance method (19–62 mm/year); water-table fluctuation method (2–50 mm/year); Darcian flownet computations (16–28 mm/year); 14C ...

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

    OpenAIRE

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

    2016-01-01

    Water scarcity contributes to the poverty of around one-third of the world’s people. Despite many benefits, tree planting in dry regions is often discouraged by concerns that trees reduce water availability. Yet relevant studies from the tropics are scarce, and the impacts of intermediate tree cover remain unexplored. We developed and tested an optimum tree cover theory in which groundwater recharge is maximized at an intermediate tree density. Below this optimal tree density the benefits fro...

  4. Effects of Hysteresis on Groundwater Recharge From Ephemeral Flows

    Science.gov (United States)

    Parissopoulos, G. A.; Wheater, H. S.

    1992-11-01

    The effects of hysteresis on the movement of the saturated and unsaturated soil water phase due to infiltration from ephemeral surface water flows are investigated for different scenarios of flood events in homogeneous and heterogeneous media with the use of a two-dimensional model based on Richards' equation and the dependent domain hysteresis model of Mualem (1984). Hysteresis effects were found in general to be small, but sensitive to water ponding depth, hydraulic contact between surface and groundwater and initial moisture distribution. In all cases tested, hysteresis resulted in higher rise of the toe of the water mound formed beneath the wadi despite a decrease of cumulative infiltration.

  5. The influence of model structure on groundwater recharge rates in climate-change impact studies

    Science.gov (United States)

    Moeck, Christian; Brunner, Philip; Hunkeler, Daniel

    2016-08-01

    Numerous modeling approaches are available to provide insight into the relationship between climate change and groundwater recharge. However, several aspects of how hydrological model choice and structure affect recharge predictions have not been fully explored, unlike the well-established variability of climate model chains—combination of global climate models (GCM) and regional climate models (RCM). Furthermore, the influence on predictions related to subsoil parameterization and the variability of observation data employed during calibration remain unclear. This paper compares and quantifies these different sources of uncertainty in a systematic way. The described numerical experiment is based on a heterogeneous two-dimensional reference model. Four simpler models were calibrated against the output of the reference model, and recharge predictions of both reference and simpler models were compared to evaluate the effect of model structure on climate-change impact studies. The results highlight that model simplification leads to different recharge rates under climate change, especially under extreme conditions, although the different models performed similarly under historical climate conditions. Extreme weather conditions lead to model bias in the predictions and therefore must be considered. Consequently, the chosen calibration strategy is important and, if possible, the calibration data set should include climatic extremes in order to minimise model bias introduced by the calibration. The results strongly suggest that ensembles of climate projections should be coupled with ensembles of hydrogeological models to produce credible predictions of future recharge and with the associated uncertainties.

  6. Modeling the effects of unsaturated, stratified sediments on groundwater recharge from intermittent streams

    Science.gov (United States)

    Reid, Mark E.; Dreiss, Shirley J.

    1990-03-01

    Unsaturated, stratified sediments beneath intermittent stream channels affect groundwater recharge from these streams. Using four different cases of sediment stratification, we simulate transient, variably saturated flow in a two-dimensional (2-D) vertical cross-section between the stream and the underlying water table. These cases include: homogeneous sediments; low permeability streambed sediments; narrow, low permeability lenses; and extensive, low permeability layers. The permeability of the sediments in these cases greatly affects the timing and rate of channel loss and groundwater recharge. Flow patterns and the style of stream/water table connection are controlled by the location and geometry of low permeability sediments. In cases with homogeneous sediments and narrow, low permeability lenses, stream/water table connection occurs by a saturated column advancing from above. In cases with low permeability streambed sediments and extensive, low permeability layers, connection occurs by a water table mound building from below. The style of stream/water table connection suggests simplified physically based interaction models that may be appropriate for these settings. We compared channel loss and groundwater recharge computed using two simplified models, a Darcian seepage equation and the Green-Ampt infiltration equation, with the results from our 2-D simulations. Simplified models using parameters from the 2-D simulations appear to perform well in cases with homogeneous and low permeability streambed sediments. In cases with low permeability lenses or layers, the simplified models require calibrated parameters to perform well.

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

    International Nuclear Information System (INIS)

    Sources of groundwater recharge to the Badain Jaran Desert in China have been investigated using geochemical and isotopic techniques. Stable isotope compositions (δ18O and δ2H) of shallow groundwater and surface water from oasis lakes evolve from a starting composition considerably depleted compared to local unsaturated zone moisture, confirming inferences from chloride mass balance that direct infiltration of precipitation is not a volumetrically important source of recharge to the shallow aquifer in the study area. Shallow phreatic and deeper confined groundwater bodies appear unconnected based on chemical composition and radiocarbon activities. Hydrogeologic evidence points toward a bordering mountain range (Yabulai) as a likely recharge zone, which is consistent with tracer results. A mean residence time in the range of 1-2 ka for the desert's southeastern margin is inferred from radiocarbon. These results reveal that some replenishment to the desert aquifer is occurring but at a rate much lower than previously suggested, which is relevant for water resources planning in this ecologically sensitive area

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

    Science.gov (United States)

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

    2014-05-01

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

  9. Comparison of optimal irrigation scheduling and groundwater recharge at representative sites in the North China Plain

    Science.gov (United States)

    Ma, Ying

    2014-05-01

    The North China Plain (NCP) is an important food production area in China, facing an increasing water shortage and overexploitation of groundwater. It is critical to optimize the irrigation scheduling and accurately estimate groundwater recharge for saving water and increasing crop water use efficiency. However, the water cycle and crop responses to irrigation are quite various in different areas, because of the spatial variation of climatic, soil, water table and other management practices in the NCP. In this study, three representative sites (LC site in the piedmont plain, TZ site in the northern alluvial and lacustrine plain, YC site in the southern alluvial and lacustrine plain) were selected to compare the optimal irrigation scheduling and corresponding groundwater recharge under different hydrological years for winter wheat-summer maize double cropping system. At each site, a physically based agro-hydrological model (SWAP) was calibrated using field data of soil moisture. Then, scenarios under different irrigation time and amount were simulated. Results showed that the optimal irrigation scheduling and corresponding groundwater recharge were significant different between the three representative sites. The mean water table depth at the LC (33.0 m), YC (10.3 m), and TZ site (2.5 m) caused great different time lags of infiltrated water and groundwater contribution to evapotranspiration. Then, the most irrigation amount was required for the TZ site but the least requirement for the YC site at each hydrologic year. As most clay contents in the deep soils at the LC site increased tortuosity and limited water movement, which resulted in lower rates of recharge compared to more sandy soils at the other two sites. Averagely, using the optimal irrigation scheduling could save 2.04×109 m3 irrigation water and reduce about 84.3% groundwater over-exploitation in winter wheat growth period in the NCP. Therefore, comparison of the simulation results among the three

  10. Estimating annual effective infiltration coefficient and groundwater recharge for karst aquifers of the southern Apennines

    Directory of Open Access Journals (Sweden)

    V. Allocca

    2013-08-01

    Full Text Available To assess the mean annual groundwater recharge of the karst aquifers in southern Apennines (Italy, the estimation of the mean annual effective infiltration coefficient (AEIC was conducted by means of an integrated approach based on hydrogeological, hydrological, geomorphological, land use and soil cover analyses. We studied a large part of the southern Apennines that is covered by a meteorological network and containing 40 principal karst aquifers. Using precipitation and air temperature time series gathered through monitoring stations operating in the period 1926–2012, the annual effective precipitation (AEP was estimated, and its distribution was modelled, by considering the orographic barrier and rain shadow effects of the Apennines chain, as well as the altitudinal control. Four sample karst aquifers with available long spring discharge time series were identified for estimating the AEIC by means of the hydrological budget equation. The resulting AEIC values were correlated with other parameters that control groundwater recharge, such as the extension of outcropping karst-rock, morphological settings, land use and covering soil type. A simple correlation relationship between AEIC, lithology and the summit flat and endorheic areas was found. This empirical model has been used to estimate AEIC and mean annual groundwater recharge in other regional karst aquifers. The estimated AEIC values ranged between 48% and 78%, thus matching intervals estimated for other karst aquifers in European and Mediterranean countries. These results represent a deeper understanding of an aspect of groundwater hydrology in karst aquifers which is fundamental for the formulation of appropriate management models of groundwater resources, also taking into account mitigation strategies for climate change impacts. Finally, the proposed hydrological characterisations are also perceived as useful for the assessment of mean annual runoff over carbonate mountains, which is

  11. Estimating annual effective infiltration coefficient and groundwater recharge for karst aquifers of the southern Apennines

    Science.gov (United States)

    Allocca, V.; Manna, F.; De Vita, P.

    2013-08-01

    To assess the mean annual groundwater recharge of the karst aquifers in southern Apennines (Italy), the estimation of the mean annual effective infiltration coefficient (AEIC) was conducted by means of an integrated approach based on hydrogeological, hydrological, geomorphological, land use and soil cover analyses. We studied a large part of the southern Apennines that is covered by a meteorological network and containing 40 principal karst aquifers. Using precipitation and air temperature time series gathered through monitoring stations operating in the period 1926-2012, the annual effective precipitation (AEP) was estimated, and its distribution was modelled, by considering the orographic barrier and rain shadow effects of the Apennines chain, as well as the altitudinal control. Four sample karst aquifers with available long spring discharge time series were identified for estimating the AEIC by means of the hydrological budget equation. The resulting AEIC values were correlated with other parameters that control groundwater recharge, such as the extension of outcropping karst-rock, morphological settings, land use and covering soil type. A simple correlation relationship between AEIC, lithology and the summit flat and endorheic areas was found. This empirical model has been used to estimate AEIC and mean annual groundwater recharge in other regional karst aquifers. The estimated AEIC values ranged between 48% and 78%, thus matching intervals estimated for other karst aquifers in European and Mediterranean countries. These results represent a deeper understanding of an aspect of groundwater hydrology in karst aquifers which is fundamental for the formulation of appropriate management models of groundwater resources, also taking into account mitigation strategies for climate change impacts. Finally, the proposed hydrological characterisations are also perceived as useful for the assessment of mean annual runoff over carbonate mountains, which is another important

  12. Numerical Comparison of Artificial Recharge by Small-diameter Wells to Common Systems

    Science.gov (United States)

    Händel, F.; Liu, G.; Dietrich, P.; Liedl, R.; Fank, J.; Fank, A.; Butler, J. J.

    2013-12-01

    Scarcity of potable water has reached to a critical level all around the world. To address the temporal inequality of demand and availability of water resources, as well as additional purposes like enhancing water quality, artificial recharge is increasingly used. For shallow infiltration, such recharge methods as surface infiltration basins and trenches are commonly applied. However, these methods have significant disadvantages, e.g., enhanced clogging, evaporation, and an increased need of land use. Therefore, a new method for artificial recharge using shallow small-diameter wells is investigated. Such wells can be installed by Direct Push (DP) and water is allowed to infiltrate into aquifers by natural gravity, so that their installation and operation costs are very low. In this work, this method is compared numerically to a surface infiltration basin and a system applying horizontal filter pipes. For this, the work is divided into two parts. First, a rigorous comparison is done between the DP well and the infiltration basin. The simulated aquifer is composed of an unsaturated zone of 12 m and a saturated zone of 8 m. The results show the dependency of both methods on different components of the hydraulic conductivity, and highlight the advantages of the DP well over the basin. A small number of 5-cm shallow wells of 12 m length can be used to recharge water at the same infiltration rate as from a 60 m2 basin. When a layer of low hydraulic conductivity is present, the infiltration capacity of surface basins is significantly reduced while the adverse impacts on the wells are less pronounced due to the horizontal flow above the low conductivity layer (larger distance of water movement away from the screen). In the second part of this work, the DP wells will be compared to an operating horizontal, vadose zone artificial recharge system in Southern Styria, Austria. The water table is 3 m deep and horizontal filter pipes are used to recharge water into the shallow

  13. Quantitative estimation of groundwater recharge ratio along the riparian of the Yellow River.

    Science.gov (United States)

    Yan, Zhang; Fadong, Li; Jing, Li; Qiang, Liu; Guangshuai, Zhao

    2013-01-01

    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.

  14. Impacts of Future Climate Change and Baltic Sea Level Rise on Groundwater Recharge, Groundwater Levels, and Surface Leakage in the Hanko Aquifer in Southern Finland

    Directory of Open Access Journals (Sweden)

    Samrit Luoma

    2014-11-01

    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.

  15. The investigation of fault-controlled groundwater recharge within a suburban area of Damascus, Syria

    Science.gov (United States)

    Wannous, M.; Siebert, C.; Tröger, Uwe

    2016-08-01

    Al-Mazraa is a heavily populated suburb of Damascus (Syria) with agricultural activity. It is adjacent to the Cretaceous Qassioun Mountain Range, from which it is structurally separated by the Damascus fault. Al-Mazraa waterworks abstracts from a shallow Quaternary aquifer, whose recharge processes are unidentified. The functions of Qassioun Mountain, the Damascus fault, the agricultural activities, the ascending deeper groundwater, and the through-flowing Tora River are not well understood and they are, hence, subject to study. The application of hydrochemical parameters and ratios in combination with signatures of δD and δ18O revealed that recharge predominantly occurs in the outcropping Cretaceous rocks through subsurface passages rather than through influent conditions of the Tora River or through direct rainfall. Interestingly, high Na/Cl ratios indicate contact with volcanic rocks which exist within the Cretaceous anticline and also in the subsurface of the studied Quaternary aquifer. Evidence for deeper circulating groundwater is given, since replenishing waters are up to 4 °C warmer and have much lower nitrate concentrations than the groundwater in the study area. From these points, it is indicated that the Damascus fault is conductive in respect to groundwater, rather than being impermeable, as it is elsewhere.

  16. The investigation of fault-controlled groundwater recharge within a suburban area of Damascus, Syria

    Science.gov (United States)

    Wannous, M.; Siebert, C.; Tröger, Uwe

    2016-03-01

    Al-Mazraa is a heavily populated suburb of Damascus (Syria) with agricultural activity. It is adjacent to the Cretaceous Qassioun Mountain Range, from which it is structurally separated by the Damascus fault. Al-Mazraa waterworks abstracts from a shallow Quaternary aquifer, whose recharge processes are unidentified. The functions of Qassioun Mountain, the Damascus fault, the agricultural activities, the ascending deeper groundwater, and the through-flowing Tora River are not well understood and they are, hence, subject to study. The application of hydrochemical parameters and ratios in combination with signatures of δD and δ18O revealed that recharge predominantly occurs in the outcropping Cretaceous rocks through subsurface passages rather than through influent conditions of the Tora River or through direct rainfall. Interestingly, high Na/Cl ratios indicate contact with volcanic rocks which exist within the Cretaceous anticline and also in the subsurface of the studied Quaternary aquifer. Evidence for deeper circulating groundwater is given, since replenishing waters are up to 4 °C warmer and have much lower nitrate concentrations than the groundwater in the study area. From these points, it is indicated that the Damascus fault is conductive in respect to groundwater, rather than being impermeable, as it is elsewhere.

  17. Hydrochemistry of urban groundwater in Seoul, South Korea: effects of land-use and pollutant recharge

    Science.gov (United States)

    Choi, Byoung-Young; Yun, Seong-Taek; Yu, Soon-Young; Lee, Pyeong-Koo; Park, Seong-Sook; Chae, Gi-Tak; Mayer, Bernhard

    2005-10-01

    The ionic and isotopic compositions (δD, δ18O, and 3H) of urban groundwaters have been monitored in Seoul to examine the water quality in relation to land-use. High tritium contents (6.1-12.0 TU) and the absence of spatial/seasonal change of O-H isotope data indicate that groundwaters are well mixed within aquifers with recently recharged waters of high contamination susceptibility. Statistical analyses show a spatial variation of major ions in relation to land-use type. The major ion concentrations tend to increase with anthropogenic contamination, due to the local pollutants recharge. The TDS concentration appears to be a useful contamination indicator, as it generally increases by the order of forested green zone (average 151 mg/l), agricultural area, residential area, traffic area, and industrialized area (average 585 mg/l). With the increased anthropogenic contamination, the groundwater chemistry changes from a Ca-HCO3 type toward a Ca-Cl(+NO3) type. The source and behavior of major ions are discussed and the hydrochemical backgrounds are proposed as the basis of a groundwater management plan.

  18. Estimates of groundwater recharge rates and sources in the East Mountain area, Eastern Bernalillo County, New Mexico, 2005-12

    Science.gov (United States)

    Rice, Steven E.; Crilley, Dianna M.

    2014-01-01

    The U.S. Geological Survey, in cooperation with the Bernalillo County Public Works Division, has conducted a monitoring program in the East Mountain area of eastern Bernalillo County, New Mexico, since 2000 to better define the hydrogeologic characteristics of the East Mountain area and to provide scientific information that will assist in the sustainable management of water resources. This report presents estimates of groundwater recharge to the aquifers that supply water to a network of springs that discharged within the East Mountain area of eastern Bernalillo County during 2005–12. Chloride concentration, the mass ratio of chloride to bromide, and the stable isotope ratios of hydrogen and oxygen were used to estimate annual groundwater recharge rates and to identify the sources and timing of recharge to the aquifers in the East Mountain area. Groundwater recharge rates were estimated by using a chloride mass-balance (CMB) method applied to data from selected springs located in the study area.

  19. Estimation of groundwater recharge of shallow aquifer on humid environment in Yaounde, Cameroon using hybrid water-fluctuation and hydrochemistry methods

    OpenAIRE

    Takounjou, A. F.; Ngoupayou, J. R. N.; Riotte, Jean; Takem, G. E.; Mafany, G.; Maréchal, J. C.; Ekodeck, G. E.

    2011-01-01

    A study of environmental chloride and groundwater balance has been carried out in order to estimate their relative value for measuring average groundwater recharge under a humid climatic environment with a relatively shallow water table. The hybrid water fluctuation method allowed the split of the hydrologic year into two seasons of recharge (wet season) and no recharge (dry season) to appraise specific yield during the dry season and, second, to estimate recharge from the water table rise du...

  20. Evaluation of Groundwater Recharge Estimates in a Partially Metamorphosed Sedimentary Basin in a Tropical Environment: Application of Natural Tracers

    Science.gov (United States)

    Oteng Mensah, Felix; Alo, Clement

    2014-01-01

    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

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

    Science.gov (United States)

    Smith, Erik A.; Westenbroek, Stephen M.

    2015-01-01

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

  2. Evaluation of Groundwater Recharge Estimates in a Partially Metamorphosed Sedimentary Basin in a Tropical Environment: Application of Natural Tracers

    Directory of Open Access Journals (Sweden)

    Felix Oteng Mensah

    2014-01-01

    Full Text Available 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.

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

    Science.gov (United States)

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

    2016-04-01

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

  4. Groundwater ages from the freshwater zone of the Edwards aquifer, Uvalde County, Texas—Insights into groundwater flow and recharge

    Science.gov (United States)

    Hunt, Andrew G.; Landis, Gary P.; Faith, Jason R.

    2016-02-23

    Tritium–helium-3 groundwater ages of the Edwards aquifer in south-central Texas were determined as part of a long-term study of groundwater flow and recharge in the Edwards and Trinity aquifers. These ages help to define groundwater residence times and to provide constraints for calibration of groundwater flow models. A suite of 17 samples from public and private supply wells within Uvalde County were collected for active and noble gases, and for tritium–helium-3 analyses from the confined and unconfined parts of the Edwards aquifer. Samples were collected from monitoring wells at discrete depths in open boreholes as well as from integrated pumped well-head samples. The data indicate a fairly uniform groundwater flow system within an otherwise structurally complex geologic environment comprised of regionally and locally faulted rock units, igneous intrusions, and karst features within carbonate rocks. Apparent ages show moderate, downward average, linear velocities in the Uvalde area with increasing age to the east along a regional groundwater flow path. Though the apparent age data show a fairly consistent distribution across the study area, many apparent ages indicate mixing of both modern (less than 60 years) and premodern (greater than 60 years) waters. This mixing is most evident along the “bad water” line, an arbitrary delineation of 1,000 milligrams per liter dissolved solids that separates the freshwater zone of the Edwards aquifer from the downdip saline water zone. Mixing of modern and premodern waters also is indicated within the unconfined zone of the aquifer by high excess helium concentrations in young waters. Excess helium anomalies in the unconfined aquifer are consistent with possible subsurface discharge of premodern groundwater from the underlying Trinity aquifer into the younger groundwater of the Edwards aquifer.

  5. Application limits of the interpretation of near-surface temperature time series to assess groundwater recharge

    Science.gov (United States)

    Gosselin, J. S.; Rivard, C.; Martel, R.; Lefebvre, R.

    2016-07-01

    The main objective of this study was to test the application limits of a groundwater recharge assessment technique based on the inversion of a vertical one-dimensional numerical model of advective-conductive heat transport, using temperature time series at three different depths (1, 3, 5 m) in the unsaturated zone. For this purpose, several synthetic hourly datasets of subsurface temperatures, representing various weather, ground cover, and soil texture conditions, thus covering a wide range of groundwater recharge values, were produced with the vertical one-dimensional coupled heat and moisture transport simulator SHAW (Simultaneous Heat and Water model). Estimates of the vertical flux of water in the soil were then retrieved from these realistic temperature profiles using a simple one-dimensional numerical simulator of advective and conductive heat transport in the unsaturated zone that was developed as part of this study. The water flux was assumed constant on a weekly, monthly, semiannual, and annual basis. From these vertical water flux estimates, annual (potential) groundwater recharge rates were then computed and results were compared to those calculated previously with SHAW to assess the accuracy of the method. Results showed that, under ideal conditions, it would be possible to estimate annual recharge rates that are above 200 mm/y, with an acceptable error of less than 20%. These "ideal" conditions include the resolution of the water flux on a weekly basis, error-free temperature measurements below the soil freezing zone, and model parameter values (thermal conductivity and heat capacity of the soil) known a priori with no uncertainty. However, this work demonstrates that the accuracy of the method is highly sensitive to the uncertainty of the input model parameters of the numerical model used to carry out the inversion and to measurement errors of temperature time series. For the conditions represented in this study, these findings suggest that, despite

  6. Application of environmental tracers to delineate recharge patterns and nitrate contamination in shallow groundwater around a river

    Science.gov (United States)

    Kaown, Dugin; Koh, Eunhee; Park, Byeong-Hak; Lee, Kang-Kun

    2016-04-01

    Hydrogeochemical data, stable isotopes, chlorofluorocarbon (CFCs) and 3H-3He in groundwater were applied to characterize residence time, recharge patterns and nitrate contamination of groundwater in a small agricultural area, Yangpyung, Korea. The study area is located around a river and the measured groundwater table ranges from 1.5 to 2.65 m during the year. Most residents in the study area practice agriculture and potato, strawberry, and cabbage are the typical vegetables grown. Vegetable fields are mostly located in the upgradient area of the study area while forest and residence areas are located in the downgradient area. A lot of chemical and organic fertilizers are applied in the upgradient area. The concentration of NO3-N in groundwater showed 9.8-83.7 mg/L in the upgradient area and 0.1-22.6 mg/L in the downgradient area in 2014. It is necessary to monitor groundwater recharge patterns and transport processes of nitrate to protect surface water around the study area. The values of δ18O and δD showed that groundwater is recharged mainly from summer precipitation. The apparent groundwater ages using 3H-3He and CFCs ranged from 13 to 27 years in the upgradient area and from 25 to 35 years in the downgradient area. The NO3-N in more recently recharged groundwater showed higher concentrations while the NO3-N in older groundwater showed low concentrations. Some shallow wells in the downgradient area showed similar apparent groundwater age with that of the river water indicating groundwater-surface water interactions. A conceptual model of groundwater-surface water interactions using stable isotopes, apparent 3H-3He and CFCs age in groundwater will be useful to understand the hydrological processes and nitrate contamination of the study area.

  7. Analysis of groundwater-level response to rainfall and estimation of annual recharge in fractured hard rock aquifers, NW Ireland

    Science.gov (United States)

    Cai, Zuansi; Ofterdinger, Ulrich

    2016-04-01

    Despite fractured hard rock aquifers underlying over 65% of Ireland, knowledge of key processes controlling groundwater recharge in these bedrock systems is inadequately constrained. In this study, we examined 19 groundwater-level hydrographs from two Irish hillslope sites underlain by hard rock aquifers. Water-level time-series in clustered monitoring wells completed at the subsoil, soil/bedrock interface, shallow and deep bedrocks were continuously monitored hourly over two hydrological years. Correlation methods were applied to investigate groundwater-level response to rainfall, as well as its seasonal variations. The results reveal that the direct groundwater recharge to the shallow and deep bedrocks on hillslope is very limited. Water-level variations within these geological units are likely dominated by slow flow rock matrix storage. The rapid responses to rainfall (⩽2 h) with little seasonal variations were observed to the monitoring wells installed at the subsoil and soil/bedrock interface, as well as those in the shallow or deep bedrocks at the base of the hillslope. This suggests that the direct recharge takes place within these units. An automated time-series procedure using the water-table fluctuation method was developed to estimate groundwater recharge from the water-level and rainfall data. Results show the annual recharge rates of 42-197 mm/yr in the subsoil and soil/bedrock interface, which represent 4-19% of the annual rainfall. Statistical analysis of the relationship between the rainfall intensity and water-table rise reveal that the low rainfall intensity group (⩽1 mm/h) has greater impact on the groundwater recharge rate than other groups (>1 mm/h). This study shows that the combination of the time-series analysis and the water-table fluctuation method could be an useful approach to investigate groundwater recharge in fractured hard rock aquifers in Ireland.

  8. Study of Ground-Water Recharge Rates in the Northern Powder River Basin

    Science.gov (United States)

    Healy, R. W.; Bartos, T. T.

    2003-12-01

    Coal-bed methane (CBM) production in the Powder River Basin is growing rapidly. The Bureau of Land Management estimates that by the year 2010 there may be as many as 50,000 producing wells in the Wyoming part of the Basin alone. Development of CBM requires the pumping of water from coal seams. As water pressure in the seam is lowered, methane is released from storage. The pumped water is usually discharged into streams, channels, or impoundments. With a typical well producing about 48 cubic meters of water per day, the rate of discharge for the Basin could exceed 2.4 million cubic meters per day by 2010. The fate of that water and its impact on the environment are topics of some concern. Relevant issues include the rate at which water infiltrates and percolates to the water table, the eventual discharge of infiltrated water to surface water, and chemical changes that occur as water moves through the system. An adequate understanding of these issues requires knowledge of local and regional hydrology. This study is investigating rates of ground-water recharge under natural conditions and as impacted be CBM development. Natural recharge within the Powder River Basin occurs by both diffuse mechanisms (infiltration of precipitation and subsequent travel of water through the unsaturated zone to the water table) and focused mechanisms (infiltration from line and point sources, such as streams and ponds). Under natural conditions, the relative importance of each is difficult to assess. Discharged CBM water should substantially enhance the rate of focused recharge, with less effect expected on diffuse recharge. Objectives of this study are to estimate rates of diffuse recharge, naturally occurring focused recharge, and enhanced focused recharge due to the discharge of CBM water. Multiple approaches are being employed: chloride mass balance; tracer methods based on tritium, stable isotopes, and other compounds; Darcy/unit hydraulic gradient; water budget; water

  9. Estimation of temporal and spatial variations in groundwater recharge in unconfined sand aquifers using Scots pine inventories

    Science.gov (United States)

    Ala-aho, P.; Rossi, P. M.; Kløve, B.

    2015-04-01

    Climate change and land use are rapidly changing the amount and temporal distribution of recharge in northern aquifers. This paper presents a novel method for distributing Monte Carlo simulations of 1-D sandy sediment profile spatially to estimate transient recharge in an unconfined esker aquifer. The modelling approach uses data-based estimates for the most important parameters controlling the total amount (canopy cover) and timing (thickness of the unsaturated zone) of groundwater recharge. Scots pine canopy was parameterized to leaf area index (LAI) using forestry inventory data. Uncertainty in the parameters controlling sediment hydraulic properties and evapotranspiration (ET) was carried over from the Monte Carlo runs to the final recharge estimates. Different mechanisms for lake, soil, and snow evaporation and transpiration were used in the model set-up. Finally, the model output was validated with independent recharge estimates using the water table fluctuation (WTF) method and baseflow estimation. The results indicated that LAI is important in controlling total recharge amount. Soil evaporation (SE) compensated for transpiration for areas with low LAI values, which may be significant in optimal management of forestry and recharge. Different forest management scenarios tested with the model showed differences in annual recharge of up to 100 mm. The uncertainty in recharge estimates arising from the simulation parameters was lower than the interannual variation caused by climate conditions. It proved important to take unsaturated thickness and vegetation cover into account when estimating spatially and temporally distributed recharge in sandy unconfined aquifers.

  10. Estimating aquifer properties and distributed groundwater recharge in a hard-rock catchment of Udaipur, India

    Science.gov (United States)

    Machiwal, Deepesh; Singh, P. K.; Yadav, K. K.

    2016-09-01

    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 post-monsoon 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.

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-12-01

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

  14. Assessing the effectiveness of drywells as tools for stormwater management and aquifer recharge and their groundwater contamination potential

    Science.gov (United States)

    Edwards, Emily C.; Harter, Thomas; Fogg, Graham E.; Washburn, Barbara; Hamad, Hamad

    2016-08-01

    Drywells are gravity-fed, excavated pits with perforated casings used to facilitate stormwater infiltration and groundwater recharge in areas where drainage and diversion of storm flows is problematic. Historically, drywells have predominantly been used as a form of stormwater management in locations that receive high volumes of precipitation; however the use of drywells is increasingly being evaluated as a method to supplement groundwater recharge, especially in areas facing severe drought. Studies have shown that drywells can be an effective means to increase recharge to aquifers; however, the potential for groundwater contamination caused by polluted stormwater runoff bypassing transport through surface soil and near surface sediment has prevented more widespread use of drywells as a recharge mechanism. Numerous studies have shown that groundwater and drinking water contamination from drywells can be avoided if drywells are used in appropriate locations and properly maintained. The effectiveness of drywells for aquifer recharge depends on the hydrogeologic setting and land use surrounding a site, as well as influent stormwater quantity and quality. These parameters may be informed for a specific drywell site through geologic and hydrologic characterization and adequate monitoring of stormwater and groundwater quality.

  15. Modeling a thick unsaturated zone at San Gorgonio Pass, California: lessons learned after five years of artificial recharge

    Science.gov (United States)

    Flint, Alan L.; Ellett, Kevin M.; Christensen, Allen H.; Martin, Peter

    2012-01-01

    The information flow among the tasks of framework assessment, numerical modeling, model forecasting and hind casting, and system-performance monitoring is illustrated. Results provide an understanding of artificial recharge in high-altitude desert settings where large vertical distances may separate application ponds from their target aquifers. Approximately 3.8 million cubic meters of surface water was applied to spreading ponds from 2003–2007 to artificially recharge the underlying aquifer through a 200-meter thick unsaturated zone in the San Gorgonio Pass area in southern California. A study was conducted between 1997 and 2003, and a numerical model was developed to help determine the suitability of the site for artificial recharge. Ongoing monitoring results indicated that the existing model needed to be modified and recalibrated to more accurately predict artificial recharge at the site. The objective of this work was to recalibrate the model by using observation of the application rates, the rise and fall of the water level above a perching layer, and the approximate arrival time to the water table during the 5-yr monitoring period following initiation of long-term artificial recharge. Continuous monitoring of soil-matric potential, temperature, and water levels beneath the site indicated that artificial recharge reached the underlying water table between 3.75 and 4.5 yr after the initial application of the recharge water. The model was modified to allow the simulation to more adequately match the perching layer dynamics and the time of arrival at the water table. The instrumentation also showed that the lag time between changes in application of water at the surface and the response at the perching layer decreased from about 4 mo to less than 1 mo due to the wet-up of the unsaturated zone and the increase in relative permeability. The results of this study demonstrate the importance of iteratively monitoring and modeling the unsaturated zone in layered

  16. Contribution of cloud water to the groundwater recharge in Madeira Island: preliminary isotopic data

    Science.gov (United States)

    Prada, S.; Cruz, J. V.; Silva, M. O.; Figueira, C.

    2010-07-01

    Situated about 900 km southwest of mainland Portugal, in the North Atlantic, Madeira is the bigger and more populated island of the archipelago with the same name. It has a total area of 747 km2 and its northern slope forms a barrier that opposes the prevailing north-easterly trade winds, thus resulting in a very frequent windward fog belt, between 800-1600 a.s.l. Madeira has a 125 km2 area of indigenous altitude forests inside the windward fog belt, between 800-1600 a.s.l. (Prada et al., 2008). This area is characterized by very steep slopes, mainly exposed to the prevailing winds. When combined, factors like steep slopes, great exposure to the humid trade winds and presence of forest vegetation facilitate fog precipitation. This is why we assume that fog precipitation is a generalized phenomenon throughout Madeira’s northern slope area. To ascertain whether or not fog water contributes to groundwater recharge, a study on the stable isotopic composition was made. For that purpose, assuming a difference between isotopic composition in rain and fog (fog being enriched in heavier isotopes 2H and 18O relative to rain at the same altitude and region) (Ingraham and Mathews 1988, 1990; Clark and Fritz, 1997), several samples of fog water, rain water and groundwater were collected for stable isotopic analysis. Groundwater was collected, according to Clark and Fritz, (1997), from springs and tunnels representing perched and basal aquifers, respectively; fog water was collected on trees by hand by placing a funnel in a collection bottle and dabbing droplets which collected on the foliage, in rainless days of intense fog, under 98-100% relative humidity conditions, thus preventing sample evaporation enrichment; rain water was collected in containers with a 1 cm thick layer of mineral oil to prevent evaporation according to Clark and Fritz (1997) and School et al., (2002), representing a sample of several rain events. The preliminary stable isotopic compositions of fog

  17. Coupling of Groundwater Recharge and Biodegradation of Subsurface Crude-Oil Contamination (Invited)

    Science.gov (United States)

    Bekins, B. A.; Hostettler, F. D.; Delin, G. N.; Herkelrath, W. N.; Warren, E.; Campbell, P.; Rosenbauer, R. J.; Cozzarelli, I.

    2010-12-01

    Surface hydrologic properties controlling groundwater recharge can have a large effect on biodegradation rates in the subsurface. Two studies of crude oil contamination show that degradation rates are dramatically increased where recharge rates are enhanced. The first site, located near Bemidji, Minnesota, was contaminated in August, 1979 when oil from a pipeline rupture infiltrated into a surficial glacial outwash aquifer. Discrete oil phases form three separate pools at the water table, the largest of which is 25x75 m at a depth of 6-8 m. Gas and water concentrations and microbial community data show that methanogenic conditions prevail in this oil pool. There is extreme spatial dependence in the degradation rates such that most of the n-alkanes have been degraded in the upgradient end, but in the downgradient end n-alkane concentrations are nearly unaltered from the original spill. Recharge rates through the two ends of the oil body were estimated using a water table fluctuation method. In 2002, the more degraded end received 15.2 cm of recharge contrasted to 10.7 cm at the less degraded end. The enhanced recharge is caused by topographic focusing of runoff toward a local depression. Microbial data using the Most Probable Number method show that the methanogen concentrations are 10-100 times greater in the more degraded end of the oil body suggesting that a growth nutrient is supplied by recharge. A decrease in partial pressure of N2 compared to Ar in the soil gas indicates nitrogen fixation probably meets N requirements (Amos et al., 2005, WRR, doi:10.1029/2004WR003433). Organic phosphorus is the main form of P in infiltrating pore water and concentration decreases with depth. The second site is located 40 km southeast of the Bemidji site at an oil pipeline pumping station near Cass Lake, Minnesota. This site was contaminated by oil leaking from a pipe coupling for an unknown duration of time between 1971 and 2002. The oil body at this site lies under a fenced

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-03-15

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

  19. Groundwater recharge history and hydrogeochemical evolution in the Minqin Basin, North West China

    International Nuclear Information System (INIS)

    The Minqin Basin is a type area for examining stress on groundwater resources in the Gobi Desert, and has been investigated here using a combination of isotopic, noble gas and chemical indicators. The basin is composed of clastic sediments of widely differing grain size and during the past half century over 10 000 boreholes have been drilled with a groundwater decline of around 1 m a-1. Modern diffuse recharge is unlikely to exceed 3 mm a-1, as determined using unsaturated zone profiles and Cl- mass balance. A small component of modern (3H-3He data, probably from irrigation returns. A clear distinction is found between modern waters with median δ 18O values of 6.5 ± 0.5 per mille and most groundwaters in the basin with more depleted isotopic signatures. Radiocarbon values as pmc range from 0.6% to 85% modern, but it is difficult to assign absolute ages to these, although a value of 20% modern C probably represents the late Pleistocene to Holocene transition. The δ 13C compositions remain near-constant throughout the basin (median value of -8.1 per mille δ 13C) and indicate that carbonate reactions are unimportant and also that little reaction takes place. There is a smooth decrease in 14C activity accompanied by a parallel increase in 4He accumulations from S-N across the basin, which define the occurrence of a regional flow system. Noble gas temperatures indicate recharge temperatures of about 5.6 deg. C for late Pleistocene samples, which is some 2-3 deg. C cooler than the modern mean annual air temperature and the recharge temperature obtained from several Holocene samples. Groundwaters in the Minqin Basin have salinities generally below 1 g/L and are aerobic, containing low Fe but elevated concentrations of U, Cr and Se (mean values of 27.5, 5.8 and 5.3 μg L-1, respectively). Nitrate is present at baseline concentrations of around 2 mg L-1 but there is little evidence of impact of high NO3 from irrigation returns. Strontium isotope and major ion ratios

  20. Joint inference of groundwater-recharge and hydraulic-conductivity fields from head data using the ensemble Kalman filter

    Science.gov (United States)

    Erdal, D.; Cirpka, O. A.

    2016-02-01

    Regional groundwater flow strongly depends on groundwater recharge and hydraulic conductivity. Both are spatially variable fields, and their estimation is an ongoing topic in groundwater research and practice. In this study, we use the ensemble Kalman filter as an inversion method to jointly estimate spatially variable recharge and conductivity fields from head observations. The success of the approach strongly depends on the assumed prior knowledge. If the structural assumptions underlying the initial ensemble of the parameter fields are correct, both estimated fields resemble the true ones. However, erroneous prior knowledge may not be corrected by the head data. In the worst case, the estimated recharge field resembles the true conductivity field, resulting in a model that meets the observations but has very poor predictive power. The study exemplifies the importance of prior knowledge in the joint estimation of parameters from ambiguous measurements.

  1. Streamflow, Infiltration, and Ground-Water Recharge at Abo Arroyo, New Mexico

    Science.gov (United States)

    Stewart-Deaker, Amy E.; Stonestrom, David A.; Moore, Stephanie J.

    2007-01-01

    Abo Arroyo, an ephemeral tributary to the Rio Grande, rises in the largest upland catchment on the eastern side of the Middle Rio Grande Basin (MRGB). The 30-kilometer reach of channel between the mountain front and its confluence with the Rio Grande is incised into basin-fill sediments and separated from the regional water table by an unsaturated zone that reaches 120 meters thick. The MRGB portion of the arroyo is dry except for brief flows generated by runoff from the upland catchment. Though brief, ephemeral flows provide a substantial fraction of ground-water recharge in the southeastern portion of the MRGB. Previous estimates of average annual recharge from Abo Arroyo range from 1.3 to 21 million cubic meters. The current study examined the timing, location, and amount of channel infiltration using streamflow data and environmental tracers during a four-year period (water years 1997?2000). A streamflow-gaging station (?gage?) was installed in a bedrock-controlled reach near the catchment outlet to provide high-frequency data on runoff entering the basin. Streamflow at the gage, an approximate bound on potential tributary recharge to the basin, ranged from 0.8 to 15 million cubic meters per year. Storm-generated runoff produced about 98 percent of the flow in the wettest year and 80 percent of the flow in the driest year. Nearly all flows that enter the MRGB arise from monsoonal storms in July through October. A newly developed streambed temperature method indicated the presence and duration of ephemeral flows downstream of the gage. During the monsoon season, abrupt downward shifts in streambed temperatures and suppressed diurnal ranges provided generally clear indications of flow. Streambed temperatures during winter showed that snowmelt is also effective in generating channel infiltration. Controlled infiltration experiments in dry arroyo sediments indicated that most ephemeral flow is lost to seepage before reaching the Rio Grande. Streambed temperature

  2. Risk assessment of three fluoroquinolone antibiotics in the groundwater recharge system.

    Science.gov (United States)

    Chen, Guoli; Liu, Xiang; Tartakevosky, Daniel; Li, Miao

    2016-11-01

    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. PMID:27400060

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

    Science.gov (United States)

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

    2009-12-01

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

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

    Science.gov (United States)

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

    2016-09-01

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

  5. Fens as whole-ecosystem gauges of groundwater recharge under climate change

    Science.gov (United States)

    Drexler, Judith Z.; Knifong, Donna; Tuil, JayLee; Flint, Lorraine E.; Flint, Alan L.

    2013-02-01

    SummaryCurrently, 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 peatlands 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

  6. Fens as whole-ecosystem gauges of groundwater recharge under climate change

    Science.gov (United States)

    Drexler, Judith Z.; Knifong, Donna L.; JayLee Tuil; Flint, Lorraine E.; Flint, Alan L.

    2013-01-01

    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

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

    Science.gov (United States)

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

    2015-04-01

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

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

    Science.gov (United States)

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

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

  9. Estimation of groundwater recharge and vulnerability by tritium data in Hungary

    International Nuclear Information System (INIS)

    Full text: Tritium is an excellent tool for proving of the protected groundwater (containing no component younger than 50 years) and for estimation of infiltration and recharge rate. Annual mean tritium record of precipitation revealing for Hungary shows that the present tritium content of the precipitation fallen before 1952, is not detectable (z), infiltration rate (I) and the vertical hydraulic conductivity (kz) were estimated by the present depth of tritium peak (h63) and of zero tritium content (h52). According to our field studies in a recharge area of the regional groundwater flow regime of the Great Hungarian Plain the vertical flow velocity was calculated as vz 200-250 mm/a. The infiltration rate was estimated as I = 40 to 50 mm/a, assuming n0 = 0.2 porosity. Vertical hydraulic conductivity looks be very low as kz = (5 to 13) * 10-8 m/s. Same method was used for estimation of the vertical flow velocity and infiltration rate through the unsaturated zone in loess soil at the prospective nuclear waste disposal. Tritium samples were extracted from the soil samples taken from dug-wells at the construction. Infiltration rates of 5 to 10 mm/a (1 to 2% of the total precipitation) and n0 0,07 effective porosity were estimated by the method of tritium peak combined with tritium balance calculations. Horizontal groundwater flow originating from the Danube with velocity arriving 500 m/a, was detected by the tritium peak method in 1992 in NW Hungary (Szigetkoez area) in the more hundred meters thick gravel aquifer. Longitudinal dispersion coefficient of the gravel aquifer was estimated as 300 m by tritium and 3He data. Repeating the tritium sampling five and ten years later the shift of the tritium peak provided useful information about the changes of the groundwater regime. Groundwater flow velocities, infiltration rates and hydraulic conductivities can be estimated directly from tritium data but the main consume is the verification of hydraulic modeling. (author)

  10. Groundwater conceptualization and modeling using distributed SWAT-based recharge for the semi-arid agricultural Neishaboor plain, Iran

    Science.gov (United States)

    Izady, A.; Davary, K.; Alizadeh, A.; Ziaei, A. N.; Akhavan, S.; Alipoor, A.; Joodavi, A.; Brusseau, M. L.

    2015-02-01

    Increased irrigation in the Neishaboor watershed, Iran, during the last few decades has caused serious groundwater depletion, making the development of comprehensive mitigation strategies and tools increasingly important. In this study, SWAT and MODFLOW were employed to integratively simulate surface-water and groundwater flows. SWAT and MODFLOW were iteratively executed to compute spatial and temporal distributions of hydrologic components. The combined SWAT-MODFLOW model was calibrated (2000-2010) and validated (2010-2012) based on streamflow, wheat yield, groundwater extraction, and groundwater-level data. This multi-criteria calibration procedure provided greater confidence for the partitioning of water between soil storage, actual evapotranspiration, and aquifer recharge. The SWAT model provided satisfactory predictions of the hydrologic budget for the watershed outlet. It also provided good predictions of irrigated wheat yield and groundwater extraction. The 10-year mean annual recharge rate estimated using the combined model varied greatly, ranging from 0 to 960 mm, with an average of 176 mm. This result showed good agreement with the independently estimated annual recharge rate from an earlier study. The combined model provides a robust tool for the sustainable planning and management of water resources for areas with stressed aquifers where interaction between groundwater and surface water cannot be easily assessed.

  11. Stable isotope ratios in meteoric recharge and groundwater at Mt. Vulture volcano, southern Italy

    Science.gov (United States)

    Paternoster, M.; Liotta, M.; Favara, R.

    2008-01-01

    SummaryA rain gauge network consisting of five sites located at different altitudes, ranging from 320 to 1285 m.a.s.l., was installed at Mt. Vulture volcano (southern Italy). Rain water samples were collected monthly over a two-year period and their isotopic composition (δ 18O and δD) was analyzed. During the same period, circulating groundwater was sampled from 24 springs and wells distributed throughout the study area. Monthly isotopic composition values were used to determine the local meteoric water line (LMWL). Its slope is slightly lower than the relationship defined by Longinelli and Selmo (Longinelli, A., Selmo, E., 2003. Isotopic composition of precipitation in Italy: a first overall map. J. Hydrol. 270, 75-88) for southern Italy. The groundwater samples analyzed were distributed essentially along the LMWL. The weighted local meteoric water line (WLMWL), defined through the mean values weighted by the rainfall amount, however, may define in a short range the meteoric end-member in the local hydrological cycle more precisely. Since most of the groundwater sampling locations do not show seasonal variations in their stable isotope values, the flow system appears to be relatively homogeneous. The mean altitude of the recharge by rainfall infiltration was estimated on the basis of the local vertical isotopic gradient δ 18O. A few springs, which show anomalous isotopic values, reveal more regional circulation systems, associated with tectonic structures responsible for the ascent of deeper water.

  12. Role of the Lakes in Groundwater Recharge and Discharge in the Young Glacial Area, Northern Poland.

    Science.gov (United States)

    Jaworska-Szulc, Beata

    2016-07-01

    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 (<100 mg/l). Two groups of losing lakes were delineated: ones with very low TDS and another group with slightly higher TDS (due to local contact with groundwater). Flow-through lakes with TDS of 170-200 mg/l were also delineated.

  13. Can groundwater in the discharge area receive recharge from rainfall in semi-arid areas?

    Science.gov (United States)

    Jiang, Xiao-Wei; Sun, Zhi-Chao; Zhao, Ke-Yu; Wan, Li; Wang, Xu-Sheng

    2016-04-01

    The definition of discharge area, which could be traced back to Toth (1962), is an area where the flow of groundwater is directed upward with respect to the water table. However, such a definition is subjected to criticism because it is usually accepted that rainfall can infiltrate into the subsurface and recharge the aquifer. In this study, the water table and soil moisture in the discharge area of an inland watershed in northwestern China with a semi-arid climate are monitored. The water table is recorded using Diver, while soil moistures at ten different depths are recorded using 5TM. The hourly rainfall data is also available in a nearby weather station. Both groundwater and soil water are found to have responses to heavy rainfalls. Soil moisture in the shallow part (soil moisture is dependent on the amount of rainfall. Soil moisture in the deep part (>90 cm) also have response to heavy rainfalls, however, they have a more direct relation to the dynamics of the water table. Based on the variations in soil moisture, we conclude that the rise in water table is not caused by the in situ infiltration of rainfall, and the infiltrated rainfall got evaporated before arriving at the water table. The vertical flux from regional groundwater flow is found to be the main contribution of water supply to support evaporation.

  14. Impacts on groundwater recharge areas of megacity pumping: analysis of potential contamination of Kolkata, India, water supply

    Science.gov (United States)

    Sahu, Paulami; Michael, Holly A.; Voss, Clifford I.; Sikdar, Pradip K.

    2013-01-01

    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.

  15. Estimation of temporal and spatial variations in groundwater recharge in unconfined sand aquifers using Scots pine inventories

    Directory of Open Access Journals (Sweden)

    P. Ala-aho

    2014-07-01

    Full Text Available Climate change and land use are rapidly changing the amount and temporal distribution of recharge in northern aquifers. This paper presents a novel method for distributing Monte Carlo simulations of 1-D soil profile spatially to estimate transient recharge in an unconfined esker aquifer. The modeling approach uses data-based estimates for the most important parameters controlling the total amount (canopy cover and timing (depth of the unsaturated zone of groundwater recharge. Scots pine canopy was parameterized to leaf area index (LAI using forestry inventory data. Uncertainty in the parameters controlling soil hydraulic properties and evapotranspiration was carried over from the Monte Carlo runs to the final recharge estimates. Different mechanisms for lake, soil, and snow evaporation and transpiration were used in the model set-up. Finally, the model output was validated with independent recharge estimates using the water table fluctuation method and baseflow estimation. The results indicated that LAI is important in controlling total recharge amount, and the modeling approach successfully reduced model uncertainty by allocating the LAI parameter spatially in the model. Soil evaporation compensated for transpiration for areas with low LAI values, which may be significant in optimal management of forestry and recharge. Different forest management scenarios tested with the model showed differences in annual recharge of up to 100 mm. The uncertainty in recharge estimates arising from the simulation parameters was lower than the interannual variation caused by climate conditions. It proved important to take unsaturated depth and vegetation cover into account when estimating spatially and temporally distributed recharge in sandy unconfined aquifers.

  16. Groundwater recharge areas of a volcanic aquifer system inferred from hydraulic, hydrogeochemical and stable isotope data: Mount Vulture, southern Italy

    Science.gov (United States)

    Parisi, Serena; Paternoster, Michele; Kohfahl, Claus; Pekdeger, Asaf; Meyer, Hanno; Hubberten, Hans Wolfgang; Spilotro, Giuseppe; Mongelli, Giovanni

    2011-02-01

    Environmental isotope techniques, hydrogeochemical analysis and hydraulic data are employed to identify the main recharge areas of the Mt. Vulture hydrogeological basin, one of the most important aquifers of southern Italy. The groundwaters are derived from seepage of rainwater, flowing from the highest to the lowest elevations through the shallow volcanic weathered host-rock fracture zones. Samples of shallow and deep groundwater were collected at 48 locations with elevations ranging from 352 to 1,100 m above sea level (a.s.l.), for stable isotope (δ18O, δD) and major ion analyses. A complete dataset of available hydraulic information has been integrated with measurements carried out in the present study. Inferred recharge elevations, estimated on the basis of the local vertical isotopic gradient of δ18O, range between 550 and 1,200 m a.s.l. The isotope pattern of the Quaternary aquifer reflects the spatial separation of different recharge sources. Knowledge of the local hydrogeological setting was the starting point for a detailed hydrogeochemical and isotopic study to define the recharge and discharge patterns identifying the groundwater flow pathways of the Mt. Vulture basin. The integration of all the data allowed for the tracing of the groundwater flows of the Mt. Vulture basin.

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

    Science.gov (United States)

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

    2014-07-01

    A dual-flow multimedia stormwater filter integrated with a groundwater recharge system was developed and tested for hydraulic efficiency and pollutant removal efficiency. The influent stormwater first flows horizontally through the circular layers of planted grass and biofibers. Subsequently, the flow direction changes to a vertical direction so that water moves through layers of pebbles and sand and finally gets recharged to the deep aquifers. The media in the sequence of vegetative medium:biofiber to pebble:sand were filled in nine proportions and tested for the best performing combination. Three grass species, viz., Typha (Typha angustifolia), Vetiver (Chrysopogon zizanioides), and St. Augustine grass (Stenotaphrum secundatum), were tested as the best performing vegetative medium. The adsorption behavior of Coconut (Cocos nucifera) fiber, which was filled in the middle layer, was determined by a series of column and batch studies.The dual-flow filter showed an increasing trend in hydraulic efficiency with an increase in flowrate. The chemical removal efficiency of the recharge dual-flow filter was found to be very high in case of K+ (81.6%) and Na+ (77.55%). The pH normalizing efficiency and electrical conductivity reduction efficiency were also recorded as high. The average removal percentage of Ca2+ was moderate, while that of Mg2+ was very low. The filter proportions of 1:1 to 1:2 (plant:fiber to pebble:sand) showed a superior performance compared to all other proportions. Based on the estimated annual costs and returns, all the financial viability criteria (internal rate of return, net present value, and benefit-cost ratio) were found to be favorable and affordable to farmers in terms of investing in the developed filtration system. PMID:25112029

  18. Integrating lysimeter drainage and eddy covariance flux measurements in a groundwater recharge model

    DEFF Research Database (Denmark)

    Vasquez, Vicente; Thomsen, Anton Gårde; Iversen, Bo Vangsø;

    2015-01-01

    Field scale water balance is difficult to characterize because controls exerted by soils and vegetation are mostly inferred from local scale measurements with relatively small support volumes. Eddy covariance flux and lysimeters have been used to infer and evaluate field scale water balances...... because they have larger footprint areas than local soil moisture measurements.. This study quantifies heterogeneity of soil deep drainage (D) in four 12.5 m2 repacked lysimeters, compares evapotranspiration from eddy covariance (ETEC) and mass balance residuals of lysimeters (ETwbLys), and models D...... to estimate groundwater recharge. Variation in measured D was attributed to redirection of snowmelt infiltration and differences in lysimeter hydraulic properties caused by surface soil treatment. During the growing seasons of 2010, 2011, and 2012, ETwbLys (278, 289, 269 mm) was in good agreement with ETEC...

  19. Groundwater recharge and capillary rise in a clayey catchment: modulation by topography and the Arctic Oscillation

    Directory of Open Access Journals (Sweden)

    T. M. Schrøder

    2004-01-01

    Full Text Available The signature left by capillary rise in the water balance is investigated for a 16 km2 clayey till catchment in Denmark. Integrated modelling for 1981–99 substantiates a 30% uphill increase in average net recharge, caused by the reduction in capillary rise when the water table declines. Calibration of the groundwater module is constrained by stream flow separation and water table wells. Net recharge and a priori parameterisation has been estimated from those same data, an automatic rain gauge and electrical sounding. Evaluation of snow storage and compensation for a simplified formulation of unsaturated hydraulic conductivity contribute to a modelling of the precipitation-runoff relation that compares well with measurements in other underdrained clayey catchments. The capillary rise is assumed to be responsible for a 30% correlation between annual evapotranspiration and the North Atlantic Oscillation. The observed correlation, and the hypothesis of a hemispherical Arctic Oscillation linking atmospheric pressure with surface temperature, suggests that modelled evapotranspiration from clayey areas is better than precipitation records for identifying the region influenced by oscillation. Keywords: catchment modelling, MIKE SHE, capillary rise, degree-day model, climate

  20. Ground-water recharge in Fortymile Wash near Yucca Mountain, Nevada, 1992-93

    International Nuclear Information System (INIS)

    Ground-water recharge occurred after five separate streamflow event periods in the Pah Canyon area of Fortymile Wash approximately 10 kilometers from Yucca Mountain, Nevada during 1992-93. Ground-water levels rose in two wells, UE-29 a No.1 and UE-29 a No.2, and one neutron-access borehole, UE-29 UZN-91, after each streamflow event period. A maximum rise of 2.9 meters occurred at UE-29 a No.1 thirteen days after the largest streamflow event where depth to water changed from 27.3 to 24.4 meters. Water levels fluctuated 3.89 meters in UE-29 a No.1, 2.92 meters in UE-29 a No.2, and 2.10 meters in UE-29 UZN-91 during the period January, 1992 to September, 1993. During two of the streamflow event periods, one in 1992 and one in 1993, there was flow around the neutron-access borehole located in the Fortymile Wash channel. Three other streamflow event periods were documented in Pah Canyon Wash but the streamflow infiltrated prior to reaching the neutron-access borehole location. Volumetric-water-content profiles were measured periodically in the neutron-access borehole. After the 1992 streamflow event period, water content increased in the upper six meters of the unsaturated zone. After the 1993 streamflow event period, water content increased in the entire unsaturated section, approximately 16 meters thick at the neutron-access borehole. Water levels in the neutron-access borehole rose even when there was no apparent water movement through the unsaturated zone as inferred by changes in the volumetric-water contents. This rise is attributed to ground-water recharge from nearby infiltration of Pah Canyon Wash streamflow. A groundwater mound probably formed beneath Pah Canyon Wash and spread laterally as evidence by larger rises in water levels in UE-29 a No.1 and UE-29 a No.2, which are closer to Pah Canyon Wash than UE-29 UZN-91

  1. Recharge source and hydrogeochemical evolution of shallow groundwater in a complex alluvial fan system, southwest of North China Plain

    Science.gov (United States)

    Li, Fadong; Pan, Guoying; Tang, Changyuan; Zhang, Qiuying; Yu, Jingjie

    2008-09-01

    Many cities around the world are developed at alluvial fans. With economic and industrial development and increase in population, quality and quantity of groundwater are often damaged by over-exploitation in these areas. In order to realistically assess these groundwater resources and their sustainability, it is vital to understand the recharge sources and hydrogeochemical evolution of groundwater in alluvial fans. In March 2006, groundwater and surface water were sampled for major element analysis and stable isotope (oxygen-18 and deuterium) compositions in Xinxiang, which is located at a complex alluvial fan system composed of a mountainous area, Taihang Mt. alluvial fan and Yellow River alluvial fan. In the Taihang mountainous area, the groundwater was recharged by precipitation and was characterized by Ca-HCO3 type water with depleted δ18O and δD (mean value of -8.8‰ δ18O). Along the flow path from the mountainous area to Taihang Mt. alluvial fan, the groundwater became geochemically complex (Ca-Na-Mg-HCO3-Cl-SO4 type), and heavier δ18O and δD were observed (around -8‰ δ18O). Before the surface water with mean δ18O of -8.7‰ recharged to groundwater, it underwent isotopic enrichment in Taihang Mt. alluvial fan. Chemical mixture and ion exchange are expected to be responsible for the chemical evolution of groundwater in Yellow River alluvial fan. Transferred water from the Yellow River is the main source of the groundwater in the Yellow River alluvial fan in the south of the study area, and stable isotopic compositions of the groundwater (mean value of -8.8‰ δ18O) were similar to those of transferred water (-8.9‰), increasing from the southern boundary of the study area to the distal end of the fan. The groundwater underwent chemical evolution from Ca-HCO3, Na-HCO3, to Na-SO4. A conceptual model, integrating stiff diagrams, is used to describe the spatial variation of recharge sources, chemical evolution, and groundwater flow paths in the

  2. Comparison of Groundwater Recharge under Irrigated Cropland versus Natural Land in Clayey Soils under Mediterranean Climate in Israel

    Science.gov (United States)

    Kurtzman, D.; Scanlon, B. R.

    2010-12-01

    Land use change from natural ecosystems to cropland influences groundwater recharge, including water quantity and quality. Soil core samples (0-11 m depth) from 6 boreholes beneath irrigated cropland (field crops) and 2 boreholes beneath natural ecosystems, in clayey soils undelain by sands, were analyzed for grain-size distribution, water content, and water-extractable Cl. Chloride mass balance and numerical 1D unsaturated zone flow and transport modeling were used for assessing average and transient recharge fluxes, and for testing matrix versus preferential flow hypotheses. Water contents under irrigated cropland are significantly higher than those found under natural land with similar grain-size distribution. Pore water Cl concentrations in deep unsaturated zone under irrigated cropland (900-2000 mg/L) are similar to recent local groundwater Cl and significantly lower than pore water Cl in deep unsaturated zone under natural ecosystems (3000 and 6000 mg/L, Figure 1). Calibrated models’ recharge rates through the soil matrix are much higher under irrigated cropland (90-230 mm/yr) than under natural ecosystems (0-2 mm/yr) and are consistent with groundwater balance estimates of average recharge (110-160 mm/yr). In contrast, matrix-recharge rates under natural ecosystems are much lower than those based on groundwater balance (50-80 mm/yr). While matrix flow in the unsaturated zone under irrigated cropland explains both groundwater and unsaturated zone observations, under natural land, preferential flow paths are needed for supporting unsaturated zone observations and pre-extensive-cultivation groundwater Cl concentrations. Plowing and irrigation prevent development of crack networks and promote matrix percolation through the clay, which flushes salts from previously immobile unsaturated zone pore-water. After flushing is completed, water recharge fluxes are correlated to precipitation of the recent and previous year, while the salinity of recharging water

  3. Groundwater recharge in Pleistocene sediments overlying basalt aquifers in the Palouse Basin, USA: modeling of distributed recharge potential and identification of water pathways

    NARCIS (Netherlands)

    Dijksma, R.; Brooks, E.S.; Boll, J.

    2011-01-01

    Groundwater levels in basalt aquifers around the world have been declining for many years. Understanding water pathways is needed for solutions like artificial drainage. Water supply in the Palouse Basin, Washington and Idaho, USA, primarily relies on basalt aquifers. This study presents a combinati

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

    International Nuclear Information System (INIS)

    Groundwater composition evolves along flow paths from recharge to discharge in response to interactions with bedrock and fracture-filling minerals, and dissolution of soluble (Cl-rich) salts in the rock matrix. The groundwater redox potential changes from oxidizing to reducing conditions due, initially, to rapid consumption of dissolved oxygen by organics in the upper ∼100 m of bedrock and, subsequently, interaction with Fe (II)-containing minerals. Measured Eh values of groundwaters at depth in the granitic Lac du Bonnet batholith indicate that biotite and chlorite control groundwater redox potential. This is supported by other geochemical characteristics such as absence of CH4, H2S, H2, NO3, low concentrations of Fe (II), and abundance of SO4. Further evidence of evolution of redox conditions is given by variations in U concentration ranging from up to 1000 μg/L in dilute near-surface waters to <1 μg/L in some deep, saline groundwaters. Groundwaters at about 400 m depth in a recharge area on the Lac du Bonnet batholith contain significantly more U than groundwaters further along the flow path or near surface in discharge areas. Uranium concentration is found to be a useful and sensitive indicator of redox conditions. (author)

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

    International Nuclear Information System (INIS)

    This analysis is designed to use existing modeling and analysis results as the basis for estimated groundwater flow rates into the saturated zone (SZ) site-scale model domains, both as recharge (infiltration) at the upper boundary (water table), and as underflow at the lateral boundaries. Specifically, this work compiles information on the recharge boundary conditions supplied to the base-case and alternate SZ site-scale flow models taken from (1) distributed recharge from the 1997 (D'Agnese et al. 1997 [DIRS 100131]) or 2001 (D'Agnese et al. 2002 [DIRS 158876]) SZ regional-scale (Death Valley Regional Flow System [DVRFS]) model; (2) recharge below the area of the 1997 (Wu et al. 1997 [DIRS 156453]) or 2003 (BSC 2004 [DIRS 169861]) unsaturated zone (UZ) site-scale flow model; and (3) focused recharge along Fortymile Wash. In addition, this analysis includes extraction of the groundwater flow rates simulated by the 1997 and 2001 DVRFS models coincident with the lateral boundaries of the SZ site-scale flow models. The fluxes from the 1997 DVRFS were used to calibrate the base-case SZ site-scale flow model. The 2001 DVRFS fluxes are used in the alternate SZ site-scale flow model

  6. Geospatial technology applied to the identification of groundwater recharge areas in northeastern São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Getulio Teixeira Batista

    2009-08-01

    Full Text Available Groundwater resource information is crucial for the establishment of protective measures by police makers and local managers. This article presents the findings of a research based on the application of remote sensing technology and auxiliary data for the identification of groundwater recharge areas in the Paraíba do Sul river basin, State of São Paulo, Brazil. The objective of this study was to develop a series of georreferenced geologic information and a sequence of hydrogeologic analysis to determine the location and distribution of recharge areas for future conservation purposes. The results indicate the distribution of five categories of potential recharge areas based on lineament characteristics, fracture bundles, and fracture density analysis. The top three categories should be considered as having the higher percolation quality and infiltration capacity, therefore higher potential for groundwater recharge. Significantly different results were obtained for the two major portions of the study area, crystalline rocks and unconsolidated sedimentary material, this fact hampered the development of hydrogeologic correlations for the entire basin. Results may help policy makers and managers in the development and implementation of an aquifer protection zoning program and local community activities in environmental education and conservationist interventions.

  7. Simulation of future groundwater recharge using a climate model ensemble and SAR-image based soil parameter distributions - A case study in an intensively-used Mediterranean catchment.

    Science.gov (United States)

    Herrmann, Frank; Baghdadi, Nicolas; Blaschek, Michael; Deidda, Roberto; Duttmann, Rainer; La Jeunesse, Isabelle; Sellami, Haykel; Vereecken, Harry; Wendland, Frank

    2016-02-01

    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. PMID:26190446

  8. Identifying groundwater recharge connections in the Moscow (USA) sub-basin using isotopic tracers and a soil moisture routing model

    Science.gov (United States)

    Candel, Jasper; Brooks, Erin; Sánchez-Murillo, Ricardo; Grader, George; Dijksma, Roel

    2016-06-01

    Globally, aquifers are suffering from large abstractions resulting in groundwater level declines. These declines can be caused by excessive abstraction for drinking water, irrigation purposes or industrial use. Basaltic aquifers also face these conflicts. A large flood basalt area (1.1 × 105 km2) can be found in the Northwest of the USA. This Columbia River Basalt Group (CRBG) consists of a thick series of basalt flows of Miocene age. The two major hydrogeological units (Wanapum and Grand Ronde formations) are widely used for water abstraction. The mean decline over recent decades has been 0.6 m year-1. At present day, abstraction wells are drying up, and base flow of rivers is reduced. At the eastern part of CRBG, the Moscow sub-basin on the Idaho/Washington State border can be found. Although a thick poorly permeable clay layer exists on top of the basalt aquifer, groundwater level dynamics suggest that groundwater recharge occurs at certain locations. A set of wells and springs has been monitored bi-weekly for 9 months for δ18O and δ2H. Large isotopic fluctuations and d-excess values close to the meteoric water line in some wells are indicating that recharge occurs at the granite/basalt interface through lateral flow paths in and below the clay. A soil moisture routing (SMR) model showed that most recharge occurs on the granitic mountains. The basaltic aquifer receives recharge from these sedimentary zones around the granite/basalt interface. The identification of these types of areas is of major importance for future managed-aquifer recharge solutions to solve problems of groundwater depletion.

  9. Regression Method for Estimating Long-Term Mean Annual Ground-Water Recharge Rates from Base Flow in Pennsylvania

    Science.gov (United States)

    Risser, Dennis W.; Thompson, Ronald E.; Stuckey, Marla H.

    2008-01-01

    A method was developed for making estimates of long-term, mean annual ground-water recharge from streamflow data at 80 streamflow-gaging stations in Pennsylvania. The method relates mean annual base-flow yield derived from the streamflow data (as a proxy for recharge) to the climatic, geologic, hydrologic, and physiographic characteristics of the basins (basin characteristics) by use of a regression equation. Base-flow yield is the base flow of a stream divided by the drainage area of the basin, expressed in inches of water basinwide. Mean annual base-flow yield was computed for the period of available streamflow record at continuous streamflow-gaging stations by use of the computer program PART, which separates base flow from direct runoff on the streamflow hydrograph. Base flow provides a reasonable estimate of recharge for basins where streamflow is mostly unaffected by upstream regulation, diversion, or mining. Twenty-eight basin characteristics were included in the exploratory regression analysis as possible predictors of base-flow yield. Basin characteristics found to be statistically significant predictors of mean annual base-flow yield during 1971-2000 at the 95-percent confidence level were (1) mean annual precipitation, (2) average maximum daily temperature, (3) percentage of sand in the soil, (4) percentage of carbonate bedrock in the basin, and (5) stream channel slope. The equation for predicting recharge was developed using ordinary least-squares regression. The standard error of prediction for the equation on log-transformed data was 9.7 percent, and the coefficient of determination was 0.80. The equation can be used to predict long-term, mean annual recharge rates for ungaged basins, providing that the explanatory basin characteristics can be determined and that the underlying assumption is accepted that base-flow yield derived from PART is a reasonable estimate of ground-water recharge rates. For example, application of the equation for 370

  10. Contributing recharge areas, groundwater travel time, and groundwater water quality of the Missouri River alluvial aquifer near the City of Independence, Missouri, well field, 1997-2008

    Science.gov (United States)

    Kelly, Brian P.

    2011-01-01

    The City of Independence, Missouri, operates a well field in the Missouri River alluvial aquifer. Contributing recharge areas (CRA) were last determined for the well field in 1996. Since that time, eight supply wells have been installed in the area north of the Missouri River and well pumpage has changed for the older supply wells. The change in pumping has altered groundwater flow and substantially changed the character of the CRA and groundwater travel times to the supply wells. The U.S Geological Survey, in a cooperative study with the City of Independence, Missouri, simulated steady-state groundwater flow for 2007 well pumpage, average annual river stage, and average annual recharge. Particle-tracking analysis was used to determine the CRA for supply wells and monitoring wells, and the travel time from recharge areas to supply wells, recharge areas to monitoring wells, and monitoring wells to supply wells. The simulated CRA for the well field is elongated in the upstream direction and extends to both sides of the Missouri River. Groundwater flow paths and recharge areas estimated for monitoring wells indicate the origin of water to each monitoring well, the travel time of that water from the recharge area, the flow path from the vicinity of each monitoring well to a supply well, and the travel time from the monitoring well to the supply well. Monitoring wells 14a and 14b have the shortest groundwater travel time from their contributing recharge area of 0.30 years and monitoring well 29a has the longest maximum groundwater travel time from its contributing recharge area of 1,701 years. Monitoring well 22a has the shortest groundwater travel time of 0.5 day to supply well 44 and monitoring well 3b has the longest maximum travel time of 31.91 years to supply well 10. Water-quality samples from the Independence groundwater monitoring well network were collected from 1997 to 2008 by USGS personnel during ongoing annual sampling within the 10-year contributing

  11. Groundwater Mounding in Non-uniform Aquifers with Implications for Managed Aquifer Recharge

    Science.gov (United States)

    Zlotnik, V. A.; Noel, P.; Kacimov, A. R.; Al Maktoumi, A. K.

    2015-12-01

    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).

  12. Use of environmental isotopes to study the recharge mechanisms and arsenic pollution of Bangladesh groundwater

    International Nuclear Information System (INIS)

    Groundwater is the main source of drinking water supply for over one hundred million inhabitants in Bangladesh. It is severely contaminated with arsenic, resulting in a major public health crisis for millions of people. It is now widely believed that the source of arsenic is geological in origin, not anthropogenic. But the actual release mechanisms are yet to be known. The young (Holocene) alluvial and deltaic deposits are most affected, whereas the older alluvial sediments in the north-west and the Pleistocene sediments of the uplifted Madhupur and Barind Tracts normally provide low arsenic water. Environmental isotopes like 2H, 18O, 13C, 3H and 14C are the most suitable tools for investigating a series of problems linked with the management of water resources in the alluvial and deltaic sediments of Bangladesh. Isotope Hydrology of Groundwater in Bangladesh: Implications for Characterisation and Mitigation of Arsenic in Groundwater (BGD/8/016), a Technical Cooperation Project sponsored by IAEA, carried out in 1999-2000. Total 56 nos. water samples from shallow and deep tubewells, ranging in depth 10 to 335 meters, located mostly in south-east, southwest and north-west of the country were collected for hydro-chemical and isotopic analyses. Results of isotope techniques have provided adequate information on recharge conditions and age of groundwater in the basin, that is very important and open up prospects for further investigations using isotope techniques. Shallow groundwaters (13C of As-bearing shallow waters range mostly from -3.0 per mille to -15.0 per mille. Higher arsenic concentrations are associated with higher carbon isotopic values, indicating that organic matter oxidation is not likely to play a role in arsenic mobilization in the aquifer. The carbon isotopic data indicate that the most likely process of arsenic mobilization may involve desorption from the sediments as a result of the relatively rapid and continuing (natural) renewal of shallow

  13. Long-term prediction of groundwater recharge by climate changes in the Gosan agricultural area, Jeju Island of South Korea

    Science.gov (United States)

    Koh, E. H.; Kaown, D.; Lee, K. K.

    2015-12-01

    Evaluation of long-term changes in groundwater recharge due to the climate changes is needed to secure the sustainable use of grounwater. In Jeju Island, which is composed of various formations of porous volcanic rocks, groundwater is a sole resource for water supply because of its hydrogeological characteristics. Therefore, preservation of the groundwater resource is an essential issue in the island. Prior to establishing a management plan for maintaining the groundwater resources in Jeju Island, long-term estimation of influencing factors are necessary. The Gosan study area is located in the western part of the island, where extensive agricultural activity has been performed and groundwater is a main source of supply for watering crops. In this study, we estimated the recharge changes for 100 years (2000~2099) in the Gosan agricultural area based on two climate change scenarios (RCP 4.5 and RCP 8.5) by using the HELP3 (Hydrologic Evaluation of Landfill Performance) program. The estimated component of water budget in this study are as follows (averaged in 2000~2014), precipitation: 1.28x108 m3/yr; ET: 6.49x107 m3/yr; runoff: 5.84x106 m3/yr; and recharge: 5.27x107 m3/yr. Over the 100 years of the estimated period, precipitation will have a highest increase among other meteorological parameters to be 6.16x109 m3 (RCP4.5) and 6.34 x109 m3 (RCP8.5). Increase in recharge by RCP8.5 scenario (2.75 x109 m3) will be less than that by RCP4.5 (2.77x109 m3) because ET by RCP 8.5 (ET: 3.34x109 m3; runoff: 2.27x108 m3) is estimated to be higher than ET by RCP4.5 (ET: 3.15x109 m3; runoff: 2.35x108 m3). Jeju volcanic island is known to have higher recharge proportions to the precipitation due to the distributed highly porous volcanic rocks. Therefore, variations in precipitation by climate changes would greatly affect the groundwater resource of the island. Acknowledgement: This work was supported by the research project of "Advanced Technology for Groundwater Development and

  14. Impact of climate Change on Groundwater Recharge in the Tiber River Basin (Central Italy) Using Regional Climate model Outputs

    Science.gov (United States)

    Muluneh, F. B.; Setegn, S. G.; Melesse, A. M.; Fiori, A.

    2011-12-01

    Quantification of the various components of hydrological processes in a watershed remains a challenging topic as the hydrological system is altered by many internal and external drivers. Changes in climate variables can affect the quantity and quality of various components of hydrological cycle. Among others, the local effects of climate change on groundwater resources were not fully studied in different part of the world as compared to the surface water. Moreover, understanding the potential impact of climate change on groundwater is more complex than surface water. The main objective of this study is to analyze the potential impact of climate change on Groundwater recharge in the Tiber River Basin using outputs from Regional Climate model. In this study, a physically-based watershed model called Soil Water Assessment Tool (SWAT) was used to estimate recharge characteristics and its response to climate change in Tiber River Basin (central Italy). The SWAT model was successfully calibrated and validated using observed weather and flow data for the period of 1963-1970 and 1971-1978 respectively. During calibration, the model was highly sensitivity to groundwater flow parameters. Dynamically downscaled rainfall and temperature datasets from ten Regional Climate Models (RCM) archived in 'Prediction of Regional scenarios and Uncertainties for Defining EuropeaN Climate change risks and Effects (PRUDENCE)' were used to force the model to assess the climate change impact on the study area. A quantile-mapping statistical correction procedure was applied to the RCM dataset to correct the inherent systematic biases. The climate change analysis indicated that by the end of 2080s the rainfall was found to decrease nearly up to 40% in dry period and there was an increase in temperature that could reach as high as 3 to 5 oC. By the end of 2080s the ground water recharge shows a decreasing trend as a response to changes in rainfall. However as the timing of both precipitation and

  15. A comparison of groundwater recharge estimation methods in a semi-arid, coastal avocado and citrus orchard (Ventura County, California)

    Science.gov (United States)

    Grismer, Mark E.; Bachman, S.; Powers, T.

    2000-10-01

    by progressive wetting during the winter rainy season was observed in both irrigated and non-irrigated soil profiles, confirming that groundwater recharge was rainfall driven and that micro-irrigation did not predispose the soil profile to excess rainfall recharge. The ability to make this recharge assessment, however, depended on making multiple field measurements associated with all three methods, suggesting that any one should not be used alone.

  16. Long Term Empirical Relations between Storm Characteristics and Episodic Groundwater Recharge across Geographic and Land-Use Gradients

    Science.gov (United States)

    Tashie, A.; Mirus, B. B.; Pavelsky, T.

    2015-12-01

    Shallow aquifers are an important water resource and provide baseflow to streams, yet estimating rates of groundwater recharge is difficult. While climate change is predicted to increase the frequency and magnitude of extreme precipitation events, the resulting impact on recharge remains poorly understood. We quantify empirical relations between precipitation characteristics and episodic groundwater recharge for a wide variety of geographic and land-use types across North Carolina. We extract storm duration, magnitude, average rate, and storm intensity from precipitation records over periods of twelve to thirty-five years at ten locations, for a total of 3,544 individual storm events. Using time-series of water-table fluctuations from nearby monitoring wells, we estimate relative recharge to precipitation ratios (RPR) to identify statistical trends. RPR increases with increased storm duration, whereas RPR decreases with increasing magnitude, average rate, and intensity. Agricultural and urban areas exhibit the greatest decrease in RPR due to increasing storm magnitude, average rate, and intensity, while naturally vegetated areas exhibit a larger increase in RPR with increased storm duration. Though RPR is generally higher during the winter than the summer, this seasonal effect is magnified in the Appalachian and Piedmont regions. These statistical trends provide valuable insights into the likely consequences of climate and land-use change for water resources in humid, subtropical climates in the American southeast. If, as predicted, growing seasons lengthen and the intensity of storms increases with a warming climate, decreased recharge in Appalachia, the Piedmont, and rapidly growing urban areas in the region would further limit groundwater availability.

  17. Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Estimated Mean Annual Natural Groundwater Recharge, 2002

    Data.gov (United States)

    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...

  18. Use of regional climate models data for groundwater recharge modelling in Baltic artesian basin

    Science.gov (United States)

    Timuhins, A.; Klints, I.; Sennikovs, J.; Virbulis, J.

    2012-04-01

    Baltic artesian basin (BAB) covers about 480000 square kilometres. BAB includes territory of Latvia, Lithuania, Estonia, parts of Poland, Russia, Belarus and Baltic Sea. The closed hydrogeological mathematical model for the BAB is developed in University of Latvia and reference calculations made in steady state mode. No-flow boundary condition is applied on the bottom and side boundaries of BAB. Hydraulic head is fixed on the seabed and largest lakes, and along the main river lines. Main water supply wells also are presented in the model as a pointwise water extraction. Precipitation is the main source of the groundwater recharge in the BAB region. Infiltration parameterization is responsible for this water source in BAB model. During the early stage of calibration of BAB hydrogeological model an automatic calibration for the hydraulic conductivities of permeable layers and single infiltration rate was attempted. Performing BAB model calibration it was noted that the differences of calculated and observed hydraulic heads (used for calculating the calibration penalty function) can be reduced by introducing a spatially distributed infiltration model. The aim of the present study is improving of the infiltration model, as well as preserving a short computation time (several minutes) for the piezometric head. Direct solution of improvement of the infiltration would be a usage of the advanced hydrological models. However, an accurate hydrological model requires a lot of computational power. It should couple meteorological and hydrological parameters and requires additional calibration. The regional climate model (KNMI-RACMO2 25 km resolution) results from ENSEMBLES project are used for the spatially distributed infiltration field calculation. The infiltration field is constructed as weighted difference of 30 year averaged precipitation and evaporation fields. The weight value is calibrated and a considerable decrease of the value of penalty function of the groundwater

  19. GROUNDWATER RECHARGE POTENTIAL USING SECONDARY TREATED WASTEWATER: METHODS AND CASE STUDY IN THE SOUTHERN SAN JOAQUIN VALLEY, CALIFORNIA

    OpenAIRE

    Adhikari, Diganta Deb

    2016-01-01

    Water scarcity in a period of climate uncertainty necessitates exploring new avenues for recharging depleted groundwater. The Western United States, including the agriculturally rich San Joaquin Valley (SJV), is highly dependent on winter precipitation and accumulated snow pack to refill reservoirs for use during peak summer agricultural operations. However, severe weather patterns (such as the current drought) have drastically reduced both the amount and longevity of the snow pack resulting ...

  20. Determining flow, recharge, and vadose zonedrainage in anunconfined aquifer from groundwater strontium isotope measurements, PascoBasin, WA

    Energy Technology Data Exchange (ETDEWEB)

    mjsingleton@lbl.gov

    2004-06-29

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

  1. Determining the impacts of experimental forest plantation on groundwater recharge in the Nebraska Sand Hills (USA) using chloride and sulfate

    Science.gov (United States)

    Adane, Z. A.; Gates, J. B.

    2015-02-01

    Although impacts of land-use changes on groundwater recharge have been widely demonstrated across diverse environmental settings, most previous research has focused on the role of agriculture. This study investigates recharge impacts of tree plantations in a century-old experimental forest surrounded by mixed-grass prairie in the Northern High Plains (Nebraska National Forest), USA. Recharge was estimated using solute mass balance methods from unsaturated zone cores beneath 10 experimental plots with different vegetation and planting densities. Pine and cedar plantation plots had uniformly lower moisture contents and higher solute concentrations than grasslands. Cumulative solute concentrations were greatest beneath the plots with the highest planting densities (chloride concentrations 225-240 % and sulfate concentrations 175-230 % of the grassland plot). Estimated recharge rates beneath the dense plantations (4-10 mm yr-1) represent reductions of 86-94 % relative to the surrounding native grassland. Relationships between sulfate, chloride, and moisture content in the area's relatively homogenous sandy soils confirm that the unsaturated zone solute signals reflect partitioning between drainage and evapotranspiration in this setting. This study is among the first to explore afforestation impacts on recharge beneath sandy soils and sulfate as a tracer of deep drainage.

  2. A GIS based hydrogeomorphic approach for identification of site-specific artificial-recharge techniques in the Deccan Volcanic Province

    Indian Academy of Sciences (India)

    M N Ravi Shankar; G Mohan

    2005-10-01

    The Deccan Volcanic Province (DVP)of India,as a whole,faces a severe shortage of water despite receiving a high annual rainfall,this is primarily due to excess runoff and lack of water conservation practices.In this study,an attempt is made to identify zones favourable for the application and adaptation of site-specific artificial-recharge techniques for augmentation of groundwater through a Geographical Information System (GIS)based hydrogeomorphic approach in the Bhatsa and Kalu river basins of Thane district,in western DVP.The criteria adopted for the GIS analysis were based on the hydrogeomorphological characteristics of both basins extracted from the IRS- 1C LISS-III data supported by information on drainage pattern,DEM derived slope,lineament density,drainage density,and groundwater condition.The integrated study helps design a suitable groundwater management plan for a basaltic terrain.

  3. Restoration of Wadi Aquifers by Artificial Recharge with Treated Waste Water

    KAUST Repository

    Missimer, Thomas M.

    2012-04-26

    Fresh water resources within the Kingdom of Saudi Arabia are a rare and precious commodity that must be managed within a context of integrated water management. Wadi aquifers contain a high percentage of the naturally occurring fresh groundwater in the Kingdom. This resource is currently overused and has become depleted or contaminated at many locations. One resource that could be used to restore or enhance the fresh water resources within wadi aquifers is treated municipal waste water (reclaimed water). Each year about 80 percent of the country\\'s treated municipal waste water is discharged to waste without any beneficial use. These discharges not only represent a lost water resource, but also create a number of adverse environmental impacts, such as damage to sensitive nearshore marine environments and creation of high-salinity interior surface water areas. An investigation of the hydrogeology of wadi aquifers in Saudi Arabia revealed that these aquifers can be used to develop aquifer recharge and recovery (ARR) systems that will be able to treat the impaired-quality water, store it until needed, and allow recovery of the water for transmittal to areas in demand. Full-engineered ARR systems can be designed at high capacities within wadi aquifer systems that can operate in concert with the natural role of wadis, while providing the required functions of additional treatment, storage and recovery of reclaimed water, while reducing the need to develop additional, energy-intensive desalination to meet new water supply demands. © 2012, The Author(s). Ground Water © 2012, National Ground Water Association.

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

    International Nuclear Information System (INIS)

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

  5. Combining numerical modeling and stable isotope values to quantify groundwater recharge from the Chilean Andes to the Pampa del Tamarugal Basin, Atacama Desert, northern Chile

    Science.gov (United States)

    Dodd, J. P.; Pollyea, R.

    2014-12-01

    The Atacama Desert of northern Chile is one of the driest regions on Earth and receives less than 5mm of precipitation annually. The Pampa del Tamarugal (PdT) Basin contains the largest aquifer system in the region, yet the mechanisms and timing of aquifer recharge and continental-scale groundwater flux are poorly understood. Although there is little debate that the source of groundwater recharge is the higher elevation regions of the Andean Altiplano to the east of the PdT Basin, there remains much uncertainty surrounding the mechanisms and timing of aquifer recharge and continental-scale groundwater flux. Most recharge models of the PdT focus on surface water runoff and alluvial fan recharge on shorter time scales, but many of these models explicitly neglect deep flow pathways. Previous investigators have combined the thermal aquifer profile and 14C groundwater ages to propose an alternative conceptual model in which cold meteoric water infiltrates deep into the Cordillera before circulating upward into the PdT by thermal convection through fault-controlled migration pathways. Although this conceptual model provides a convincing theoretical argument for deep fluid circulation, it cannot constrain the magnitude of this deep recharge flux. In this work, we revisit deep-flow conceptual model by combining the spatial distribution of hydrogen and oxygen isotope values as groundwater tracers with a non-isothermal model of continental scale groundwater flow through a two-dimensional transect from the Chilean Andes to the PdT Basin. This work provides first-order estimates on the contribution of deep groundwater circulation within the PdT Aquifer, while providing a framework for (1) quantifying boundary conditions for high resolution models of groundwater resources within the PdT Aquifer, (2) assessing the influence of variable future climate scenarios for groundwater availability in the region, and (3) further integrating conservative tracers and numerical models for

  6. Using stable isotopes and hydraulic head data to investigate groundwater recharge and discharge in a fractured rock aquifer

    Science.gov (United States)

    Praamsma, Titia; Novakowski, Kent; Kyser, Kurt; Hall, Kevin

    2009-03-01

    SummaryGroundwater recharge and discharge were studied in a gneissic terrain with minimal glacial overburden at a well-instrumented field site adjacent to a 1.2 km section of the Tay River, near Perth, Ontario, Canada. Seven 31-56 m-deep monitoring wells were constructed, characterized, and sampled for 18O and 2H. Each well was first hydraulically tested using a 1.77 m straddle packer system and then instrumented with multi-level piezometers. Detailed fracture mapping and electrical conductivity surveys were conducted in a 1.2 km section of the river to identify potential groundwater discharge points. Groundwater, surface water and precipitation (rain and snow) samples were collected to measure δ 2H and δ 18O during and following several storm events, and during baseflow conditions. Results showed that groundwater flow in the upper 30-40 m of bedrock is dominated by a few horizontal fractures which are weakly connected by sparsely-arranged vertical fractures. Values of δ 2H and δ 18O indicate that precipitation does not directly influence the isotopic signature of river water and deep groundwater during a rain event. Recharge is localized and rapid where overburden is thin, however, it does not penetrate deeply into the flow system at this site. There is no hydraulic or isotopic evidence that groundwater discharges into the river over the study section, thus most of the groundwater underflows the river at this location. Flow in this reach, and likely in the bulk of the river, is controlled by an upstream dam and by surface water runoff. The results of this study suggest that the use of traditional methods for water budgeting based on equivalent porous media are highly inappropriate for this crystalline bedrock setting.

  7. Recharge and groundwater use in the North China Plain for six irrigated crops for an eleven year period.

    Science.gov (United States)

    Yang, Xiaolin; Chen, Yuanquan; Pacenka, Steven; Gao, Wangsheng; Zhang, Min; Sui, Peng; Steenhuis, Tammo S

    2015-01-01

    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.

  8. Recharge and groundwater use in the North China Plain for six irrigated crops for an eleven year period.

    Directory of Open Access Journals (Sweden)

    Xiaolin Yang

    Full Text Available 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.

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

    Science.gov (United States)

    Hopkins, Candice B.

    2013-01-01

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

  10. Application of Artificial Neural Networks to Complex Groundwater Management Problems

    International Nuclear Information System (INIS)

    As water quantity and quality problems become increasingly severe, accurate prediction and effective management of scarcer water resources will become critical. In this paper, the successful application of artificial neural network (ANN) technology is described for three types of groundwater prediction and management problems. In the first example, an ANN was trained with simulation data from a physically based numerical model to predict head (groundwater elevation) at locations of interest under variable pumping and climate conditions. The ANN achieved a high degree of predictive accuracy, and its derived state-transition equations were embedded into a multiobjective optimization formulation and solved to generate a trade-off curve depicting water supply in relation to contamination risk. In the second and third examples, ANNs were developed with real-world hydrologic and climate data for different hydrogeologic environments. For the second problem, an ANN was developed using data collected for a 5-year, 8-month period to predict heads in a multilayered surficial and limestone aquifer system under variable pumping, state, and climate conditions. Using weekly stress periods, the ANN substantially outperformed a well-calibrated numerical flow model for the 71-day validation period, and provided insights into the effects of climate and pumping on water levels. For the third problem, an ANN was developed with data collected automatically over a 6-week period to predict hourly heads in 11 high-capacity public supply wells tapping a semiconfined bedrock aquifer and subject to large well-interference effects. Using hourly stress periods, the ANN accurately predicted heads for 24-hour periods in all public supply wells. These test cases demonstrate that the ANN technology can solve a variety of complex groundwater management problems and overcome many of the problems and limitations associated with traditional physically based flow models

  11. Integrating soil water and tracer balances, numerical modelling and GIS tools to estimate regional groundwater recharge: Application to the Alcadozo Aquifer System (SE Spain).

    Science.gov (United States)

    Hornero, Jorge; Manzano, Marisol; Ortega, Lucía; Custodio, Emilio

    2016-10-15

    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

  12. Integrating soil water and tracer balances, numerical modelling and GIS tools to estimate regional groundwater recharge: Application to the Alcadozo Aquifer System (SE Spain).

    Science.gov (United States)

    Hornero, Jorge; Manzano, Marisol; Ortega, Lucía; Custodio, Emilio

    2016-10-15

    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

  13. How much does subsurface heterogeneity alter the impact of climate and land use changes on groundwater recharge?

    Science.gov (United States)

    Sarrazin, Fanny; Hartmann, Andreas; Pianosi, Francesca; Wagener, Thorsten

    2016-04-01

    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 use. In fact, climate characteristics control the supply of water to karst systems and the evaporative demand, while land use characteristics control the actual evapotranspiration losses. Understanding karst hydrology and estimating karst groundwater resources 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 explicitly taking into account karst heterogeneities, i.e. preferential flow paths. The first objective of the present study is to introduce vegetation processes into the VarKarst-R model to better estimate evapotranspiration losses depending on the land use characteristics. We test the model at Fluxnet sites located in carbonate rock areas. Secondly, the VarKarst-R model so modified is used to assess the relative influence of changes in climate and land use on aquifer recharge. We establish a sensitivity analysis framework to analyse 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).

  14. Groundwater recharge and chemical evolution in the southern High Plains of Texas, USA

    Science.gov (United States)

    Fryar, Alan; Mullican, William; Macko, Stephen

    2001-11-01

    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

  15. Estimation of groundwater recharge in arid and semi-arid areas based on water cycle simulation%基于水循环模拟的干旱半干旱地区地下水补给评价

    Institute of Scientific and Technical Information of China (English)

    陆垂裕; 孙青言; 李慧; 盖燕如

    2014-01-01

    干旱半干旱地区的地下水补给评价在地下水的开发利用和保护中起着基础性的重要作用。本文从全区域水循环整体的角度出发,以水循环模拟与地下水数值模拟紧密耦合的综合性水文模型 MODCYCLE为工具,以处于半干旱地区的通辽市平原区为例,探索地下水在“自然-社会”二元水循环过程中的补给规律。结果表明:通辽市平原区地下水的主要补给来源为降水入渗,占总补给量的65.2%;降水入渗补给量与降水量的变化趋势基本一致,但受众多因素影响,并不呈线性关系;年均降水入渗补给量农田区107.3 mm,非农田生态区29.1 mm,且前者较后者稳定;地下水从人口分布较少的平原坨沼区向社会经济活动频繁的中部平原区侧向净流动,年均净流量为6570万m3,呈逐年下降趋势。模型反映的地下水补给规律基本符合研究区域的客观情况,可以为当地地下水管理提供参考。该评价方法为类似地区的地下水研究提供一种可以选择的方式。%Groundwater recharge evaluation in arid and semi-arid areas plays a foundational role in the ex⁃ploitation and protection of the groundwater. In this study, from the perspective of water cycle for the whole region, the law of groundwater recharge is explored in the artificial-natural dual water cycle. The in⁃tegrated hydrology model named MODCYCLE is used, which is formed by the tightly-coupling of the water cycle model and the groundwater numerical simulation. The groundwater of the plain area in Tongliao, a typical semi-arid region, is evaluated as an example. The analytical results show that (1) the precipitation recharge, 65.2 % of the total recharge, is the main supply source of groundwater;(2) the variation trends of precipitation recharge and precipitation are basically consistent, but influenced by many factors, not a linear relationship;(3) the average annual amount of

  16. Using 14C and 3H to delineate a recharge 'window' into the Perth Basin aquifers, North Gnangara groundwater system, Western Australia.

    Science.gov (United States)

    Meredith, Karina; Cendón, Dioni I; Pigois, Jon-Philippe; Hollins, Suzanne; Jacobsen, Geraldine

    2012-01-01

    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

  17. Using 14C and 3H to delineate a recharge 'window' into the Perth Basin aquifers, North Gnangara groundwater system, Western Australia.

    Science.gov (United States)

    Meredith, Karina; Cendón, Dioni I; Pigois, Jon-Philippe; Hollins, Suzanne; Jacobsen, Geraldine

    2012-01-01

    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

  18. The effects of a dry sand layer on groundwater recharge in extremely arid areas: field study in the western Hexi Corridor of northwestern China

    Science.gov (United States)

    Sun, Peng; Ma, Jinzhu; Qi, Shi; Zhao, Wei; Zhu, Gaofeng

    2016-09-01

    Evaporation capacity is an important factor that cannot be ignored when judging whether extreme precipitation events will produce groundwater recharge. The evaporation layer's role in groundwater recharge was evaluated using a lysimeter simulation experiment in the desert area of Dunhuang, in the western part of the Hexi Corridor in northwestern China's Gansu Province. The annual precipitation in the study area is extremely low, averaging 38.87 mm during the 60-year study period, and daily pan evaporation amounts to 2,486 mm. Three simulated precipitation regimes (normal, 10 mm; ordinary annual maximum, 21 mm; and extreme, 31 mm) were used in the lysimeter simulation to allow monitoring of water movement and weighing to detect evaporative losses. The differences in soil-water content to a depth of 50 cm in the soil profile significantly affected rainfall infiltration during the initial stages of rainfall events. It was found that the presence of a dry 50-cm-deep sand layer was the key factor for "potential recharge" after the three rainfall events. Daily precipitation events less than 20 mm did not produce groundwater recharge because of the barrier effect created by the dry sand. Infiltration totaled 0.68 mm and penetrated to a depth below 50 cm with 31 mm of rainfall, representing potential recharge equivalent to 1.7 % of the rainfall. This suggests that only extreme precipitation events offer the possibility of recharge of groundwater in this extremely arid area.

  19. The effects of a dry sand layer on groundwater recharge in extremely arid areas: field study in the western Hexi Corridor of northwestern China

    Science.gov (United States)

    Sun, Peng; Ma, Jinzhu; Qi, Shi; Zhao, Wei; Zhu, Gaofeng

    2016-04-01

    Evaporation capacity is an important factor that cannot be ignored when judging whether extreme precipitation events will produce groundwater recharge. The evaporation layer's role in groundwater recharge was evaluated using a lysimeter simulation experiment in the desert area of Dunhuang, in the western part of the Hexi Corridor in northwestern China's Gansu Province. The annual precipitation in the study area is extremely low, averaging 38.87 mm during the 60-year study period, and daily pan evaporation amounts to 2,486 mm. Three simulated precipitation regimes (normal, 10 mm; ordinary annual maximum, 21 mm; and extreme, 31 mm) were used in the lysimeter simulation to allow monitoring of water movement and weighing to detect evaporative losses. The differences in soil-water content to a depth of 50 cm in the soil profile significantly affected rainfall infiltration during the initial stages of rainfall events. It was found that the presence of a dry 50-cm-deep sand layer was the key factor for "potential recharge" after the three rainfall events. Daily precipitation events less than 20 mm did not produce groundwater recharge because of the barrier effect created by the dry sand. Infiltration totaled 0.68 mm and penetrated to a depth below 50 cm with 31 mm of rainfall, representing potential recharge equivalent to 1.7 % of the rainfall. This suggests that only extreme precipitation events offer the possibility of recharge of groundwater in this extremely arid area.

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

    Science.gov (United States)

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

    2013-03-01

    Results are presented of a detailed study into the vadose zone and shallow water table hydrodynamics of a field site in Shropshire, UK. A conceptual model is 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.

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

    Directory of Open Access Journals (Sweden)

    M. O. Cuthbert

    2013-03-01

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

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

    Directory of Open Access Journals (Sweden)

    M. O. Cuthbert

    2012-07-01

    Full Text Available Results are presented of a detailed study into the vadose zone and shallow water table hydrodynamics of a field site in Shropshire, UK. A conceptual model is 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.

  3. Precipitation, Ground-water Hydrology, and Recharge Along the Eastern Slopes of the Sandia Mountains, Bernalillo County, New Mexico

    Science.gov (United States)

    McCoy, Kurt J.; Blanchard, Paul J.

    2008-01-01

    The spatial and temporal distribution of recharge to carbonate and clastic aquifers along the eastern slopes of the Sandia Mountains was investigated by using precipitation, water-level, dissolved chloride, and specific-conductance data. The U.S. Geological Survey (USGS), in cooperation with the Bernalillo County Public Works Division, conducted a study to assess ground-water conditions and provide technical data that could be used as a basis for management and future planning of eastern Bernalillo County water resources. The intent of the investigation was to improve the current understanding of subsurface mechanisms controlling recharge dynamics in a geologically complex aquifer system. In the Sandia Mountains, precipitation events are generally limited to snowfalls in winter months and monsoon rainfall in late summer. Monthly meteorological data from weather stations in the study area indicate that monsoon rainfall during July and August constitutes close to one-third of annual precipitation totals. Following precipitation and snowmelt events, daily ground-water level data show low-amplitude, long-duration peaks in hydrographs of wells north and west of the Tijeras Fault. Hydrographs of monthly and biannual water-level data from across the study area show seasonal variation and water-level fluctuations in excess of 30 ft during a period of below-average precipitation. Water level observations in 67 percent of wells showing drought-induced water-level declines rebounded to at or near predrought conditions within 6 months of return to normal climate conditions. Cross-correlation of annual hydrologic data shows aquifer response to periods of monsoon recharge to persist from 1 to 6 months following events. The lag time between precipitation input and response of water levels or solute concentrations was largest near the Tijeras and Gutierrez Faults. These results indicate regional faults hydrologically isolate the Tijeras Graben from groundwater recharge originating

  4. Groundwater capture processes under a seasonal variation in natural recharge and discharge

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    W. A. Timms

    2012-04-01

    Full Text Available The magnitude and timing of deep drainage and salt leaching through clay soils is a critical issue for dryland agriculture in semi-arid regions (<500 mm yr−1 rainfall, potential evapotranspiration >2000 mm yr−1 such as parts of Australia's Murray-Darling Basin (MDB. In this rare study, hydrogeological measurements and estimations of the historic water balance of crops grown on overlying Grey Vertosols were combined to estimate the contribution of deep drainage below crop roots to recharge and salinization of shallow groundwater. Soil sampling at two sites on the alluvial flood plain of the Lower Namoi catchment revealed significant peaks in chloride concentrations at 0.8–1.2 m depth under perennial vegetation and at 2.0–2.5 m depth under continuous cropping indicating deep drainage and salt leaching since conversion to cropping. Total salt loads of 91–229 t ha−1 NaCl equivalent were measured for perennial vegetation and cropping, with salinity to ≥ 10 m depth that was not detected by shallow soil surveys. Groundwater salinity varied spatially from 910 to 2430 mS m−1 at 21 to 37 m depth (N = 5, whereas deeper groundwater was less saline (290 mS m−1 with use restricted to livestock and rural domestic supplies in this area. The Agricultural Production Systems Simulator (APSIM software package predicted deep drainage of 3.3–9.5 mm yr−1 (0.7–2.1% rainfall based on site records of grain yields, rainfall, salt leaching and soil properties. Predicted deep drainage was highly episodic, dependent on rainfall and antecedent soil water content, and over a 39 yr period was restricted mainly to the record wet winter of 1998. During the study period, groundwater levels were unresponsive to major rainfall events (70 and 190 mm total, and most piezometers at about 18 m depth remained dry. In this area, at this time, recharge appears to be negligible due to low

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

    Directory of Open Access Journals (Sweden)

    W. A. Timms

    2011-11-01

    Full Text Available The magnitude and timing of deep drainage and salt leaching through clay soils is a critical issue for dryland agriculture in semi-arid regions (<500 mm yr−1 rainfall, such as parts of Australia's Murray-Darling Basin (MDB. In this unique 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 is 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, 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 negligible due to low rainfall and large potential evapotranspiration, transient hydrological conditionsafter changes

  7. Oxygen and Hydrogen Isotopes of Waters in the Ordos Basin,China: Implications for Recharge of Groundwater in the North of Cretaceous Groundwater Basin

    Institute of Scientific and Technical Information of China (English)

    YANG Yuncheng; SHEN Zhaoli; WENG Dongguang; HOU Guangcai; ZHAO Zhenhong; WANG Dong; PANG Zhonghe

    2009-01-01

    Hundreds of precipitation samples collected from meteorological stations in the Ordos Basin from January 1988 to December 2005 were used to set up a local meteoric water line and to calculate weighted average isotopic compositions of modern precipitation.Oxygen and hydrogen isotopes, with and gradually decrease in summer and fall,illustrating that the seasonal effect is considerable.They also show that the isotopic difference between south portion and north portion of the Ordos Basin are not obvious.and the isotope in the middle portion iS normally depleted.The isotope compositions of 32 samples collected from shallow groundwater(less than a depth of 150 m)in desert plateau range from for JD.Most of them are identical with modern precipitation.The isotope compositions of 22 middle and deep groundwaters(greater than a depth of 275 m)fall in ranges from-11.6‰to-8.8‰with an average of-10.2‰ for £18O and from-89‰ to-63‰ with an average of-76‰ for £D.The average values are significantly less than those of modern precipitation,illustrating that the middle and deep groundwaters were recharged at comparatively lower air temperatures.Primary analysis of 14C shows that the recharge of the middle and deep groundwaters started at late Pleistocene.The isotopes of 13 lake water samples collected from eight lakes define a local evaporation trend,with a relatively flat slope of 3.77,and show that the lake waters were mainly fed by modern precipitation and shallow groundwater.

  8. Effect of River Restoration on Ground Water Recharge: Investigation of Groundwater-Surface Water Interactions with Distributed Temperature Sensing (DTS)

    Science.gov (United States)

    Kurth, A.-M.; Schirmer, M.

    2012-04-01

    Following the EU Water Framework Directive 2000/60/EC (1) Switzerland passed the Water Protection Act 814.20 (2), obligating the cantons to restoring their surface water bodies to a near-natural state within the next 100 years. In case of rivers and streams this comprises the provision of extensive areas to allow for meandering, sufficient discharge to prevent drying-out of the river, as might be caused by hydropower production, and adequate water quality, e.g. by limiting waste water discharge. Hereby, the main aim lies in improving the ecological status of the surface water bodies, as well as flood protection and mitigation (2). However, apart from the enhancement of the water quality, river restoration has the potential to increase groundwater recharge due to improved connectivity between the surface water bodies and the underlying aquifers. A new method for the estimation of groundwater recharge in rivers is currently developed at Eawag in Switzerland, and will be employed to investigate if river restoration enhances groundwater recharge. This method comprises the use of distributed temperature sensing (DTS), as well as heatable glass-fibre optics cables. DTS is a fibre-optical method for temperature determination over long distances with high accuracy and precision (3), largely depending on the instrument settings and calibration, as well as the fibre-optics cables employed in the measurements (4). Temperature data will be used to distinguish between ground- and surface water, due to their different temperature signatures (5). By heating the glass-fibre optics cable the additional information on the cooling behaviour of the cable may be used to (i) distinguish between up- and downwelling water and to (ii) estimate the volume of water exchanged locally in the river bed. In order to separate the signal of horizontal flow from vertical flow over the cable, it will be buried 30-40 cm deep in the river bed; a control cable will be installed in 10-20 cm depth right

  9. Artificial recharge of the water-table aquifer in the latian volcano in Rome province; Ricarica artificiale dalla falda acquifera presente nel vulcano laziale in Provincia di Roma

    Energy Technology Data Exchange (ETDEWEB)

    Bersani, P.; Piotti, A. [Ambito Territoriale Ottimale, Lazio Centrale, Rome (Italy)

    2001-06-01

    The zone of the Latian Volcano extends in an area of about 1.500 km{sup 2} in the south-est of Rome. This area is thickly peopled, owing to the presence of many towns (Velletri, Frascati, Albano, etc.) in the central share of the volcanic edifice. Actually the volcanic edifice of Alban Hills shows in the central and higher area, a large caldera (Tuscolana-Artemisia). This caldera has a sub-circular form wide 10 km in diameter and 75 km{sup 2} in area. The excessive groundwater drawing by wells caused the depauperation of underground resources so to produce a real crisis since 1984. To restore of water balance of the aquifer of the Latian Volcano, an important contribution could be given by the artificial recharge of the higher aquifer. This recharge could be done by allowing to meteoric water to inflitrate as much as possible in the underground by realization of an artificial lake; otherwise by making a series of little infiltration-basins together with infiltration-wells. Besides the realization of the artificial lake could give back to the landscape a characteristic component present in the past centuries until very recent times. [Italian] L'area del Vulcano Laziale si estende su una superficie di circa 1500 km{sup 2} a sud-est di Roma in un'area densamente popolata per la presenza di numerosi centri urbani (Velletri, Frascati, Albano, ecc.), ubicati nella parte centrale dell'ufficio vulcanico. Attualmente l'edificio vulcanico dei Colli Albani presenta in posizione centrale un'ampia caldera sommitale con forma subcircolare, con diametro medio di circa 10 km ed estensione di circa 75 km{sup 2}. Gli eccessivi prelievi di acqua sotterranea hanno condotto ad un impoverimento della risorsa idrica fino a determinare una vera e propria crisi manifestatasi a partire dal 1984. Per riequilibrare il bilancio idrico dell'acquifero del Vulcano Laziale, un contributo significativo potrebbe provenire dalla ricarica artificiale dell

  10. Controls of soil hydraulic characteristics on modeling groundwater recharge under different climatic conditions

    Science.gov (United States)

    Wang, Tiejun; Franz, Trenton E.; Zlotnik, Vitaly A.

    2015-02-01

    To meet the challenge of estimating spatially varying groundwater recharge (GR), increasing attention has been given to the use of vadose zone models (VZMs). However, the application of this approach is usually constrained by the lack of field soil hydraulic characteristics (SHCs) required by VZMs. To tackle this issue, SHCs based on the van Genuchten or Brooks-Corey model are generally estimated by pedotransfer functions or taken from texture based class averages. With the increasing use of this method, it is important to elucidate the controls of SHCs on computing GR mostly due to the high nonlinearity of the models. In this study, it is hypothesized that the nonlinear controls of SHCs on computing GR would vary with climatic conditions. To test this hypothesis, a widely used VZM along with two SHCs datasets for sand and loamy sand is used to compute GR at four sites in the continental Unites States with a significant gradient of precipitation (P). The simulation results show that the distribution patterns of mean annual GR ratios (GR ‾ / P ‾ , where GR ‾ and P ‾ are mean annual GR and P, respectively) vary considerably across the sites, largely depending on soil texture and climatic conditions at each site. It is found that GR ‾ / P ‾ is mainly controlled by the shape factor n in the van Genuchten model and the nonlinear effect of n on GR ‾ / P ‾ varies with climatic conditions. Specifically, for both soil textures, the variability in GR ‾ / P ‾ is smallest at the Andrews Forest with the highest P ‾ (191.3 cm/year) and GR ‾ / P ‾ is least sensitive to n; whereas, the variability in GR ‾ / P ‾ at the Konza Prairie (P ‾ = 84.2 cm/year) is the largest and GR ‾ / P ‾ is most sensitive to n. With further decreasing P ‾ , the nonlinear effect of n weakens at the Barta Brothers (P ‾ = 57.3 cm/year) and Sevilleta (P ‾ = 20.3 cm/year), leading to smaller GR ‾ / P ‾ variability at those two sites than at the Konza Prairie. The

  11. Ground-water flow and numerical simulation of recharge from streamflow infiltration near Pine Nut Creek, Douglas County, Nevada

    Science.gov (United States)

    Maurer, Douglas K.

    2002-01-01

    Ground-water flow and recharge from infiltration near Pine Nut Creek, east of Gardnerville, Nevada, were simulated using a single-layer numerical finite-difference model as part of a study made by the U.S. Geological Survey in cooperation with the Carson Water Subconservancy District. The model was calibrated to 190 water-level measurements made in 27 wells in December 2000, and in 9 wells from August 1999 through April 2001. The purpose of this study was to estimate reasonable limits for the approximate volume of water that may be stored by recharge through infiltration basins, and the rate at which recharged water would dissipate or move towards the valley floor. Measured water levels in the study area show that infiltration from the Allerman Canal and reservoir has created a water-table mound beneath them that decreases the hydraulic gradient east of the canal and increases the gradient west of the canal. North of Pine Nut Creek, the mound causes ground water to flow toward the northern end of the reservoir. South of Pine Nut Creek, relatively high water levels probably are maintained by the mound beneath the Allerman Canal and possibly by greater rates of recharge from the southeast. Water-level declines near Pine Nut Creek from August 1999 through April 2001 probably are caused by dissipation of recharge from infiltration of Pine Nut Creek streamflow in the springs of 1998 and 1999. Using the calibrated model, a simulation of recharge through a hypothetical infiltration basin covering 12.4 acres near Pine Nut Creek applied 700 acre-feet per year of recharge over a six-month period, for a total of 3,500 acre-feet after 5 consecutive years. This recharge requires a diversion rate of about 2 cubic feet per second and an infiltration rate of 0.3 foot per day. The simulations showed that recharge of 3,500 acre-feet caused water levels near the basin to rise over 70 feet, approaching land surface, indicating 3,500 acre-feet is the maximum that may be stored in a 5

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

    Science.gov (United States)

    Wang, Shiqin; Tang, Changyuan; Song, Xianfang; Wang, Qinxue; Zhang, Yinghua; Yuan, Ruiqiang

    2014-06-01

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

  13. Impact of Land-use Patterns on Distributed Groundwater Recharge and Discharge——A Case Study of Western Jilin, China

    Institute of Scientific and Technical Information of China (English)

    Moiwo Juana PAUL

    2006-01-01

    The impact of land-use on distributed groundwater recharge and discharge in the western Jilin (WJ) was analyzed in this study. WJ is a transitional, semi-arid zone with a fragile, hydrological closed ecosystem in the Songhua River Basin (SRB). The research tool includes a seamlessly linked MODFLOW, WetSpass, the Seepage packages, and ArcGIS. The model calibration showed good agreement between simulated water table elevation and measured water table depths, while predicted groundwater discharge zones showed strong correlations with field occurrences of drainage systems and wetlands. Simulated averages for distributed recharge, water table elevation and groundwater drawdown were 377.42mm/yr, 194.43m, and 0.18m respectively. Forest vegetation showed the highest recharge, followed by agricultural farmlands, while open-water and other drainage systems constituted groundwater exit zones. When present land-use conditions were compared with the hypothetical natural pre-development scenario, an overall loss of groundwater recharge (24.09mm/yr) was observed, which for the project area is 18.05 × 108m3. Groundwater abstraction seemed to be the cause of water table drawdown, especially in the immediate vicinities of the supply wells. An important issue of the findings was the ability of the hypothetical forest vegetation to protect, and hence sustain aquifer reserves and dependent ecosystems. The profound data capture capability of ArcGIS makes it particularly useful in spatio-temporal hydroecological modeling.

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

    Science.gov (United States)

    Wang, Shiqin; Tang, Changyuan; Song, Xianfang; Wang, Qinxue; Zhang, Yinghua; Yuan, Ruiqiang

    2014-06-01

    Sewage leakage has become an important source of groundwater recharge in urban areas. Large linear wastewater ponds that lack anti-seepage measures can act as river channels that cause the deterioration of groundwater quality. This study investigated the groundwater recharge by leakage of the Tanghe Wastewater Reservoir, which is the largest industrial wastewater channel on the North China Plain. Additionally, water quality evolution was investigated using a combination of multivariate statistical methods, multi-tracers and geochemical methods. Stable isotopes of hydrogen and oxygen indicated high levels of wastewater evaporation. Based on the assumption that the wastewater was under an open system and fully mixed, an evaporation model was established to estimate the evaporation of the wastewater based on isotope enrichments of the Rayleigh distillation theory using the average isotope values for dry and rainy seasons. Using an average evaporation loss of 26.5% for the input wastewater, the estimated recharge fraction of wastewater leakage and irrigation was 73.5% of the total input of wastewater. The lateral regional groundwater inflow was considered to be another recharge source. Combing the two end-members mix model and cluster analysis revealed that the mixture percentage of the wastewater decreased from the Highly Affected Zone (76%) to the Transition Zone (5%). Ion exchange and redox reaction were the dominant geochemical processes when wastewater entered the aquifer. Carbonate precipitation was also a major process affecting evolution of groundwater quality along groundwater flow paths. PMID:24657581

  15. Evaluation of chloride mass balance of pore water as an indicator of groundwater recharge to the Monterrey Metropolitan Area, Mexico

    Science.gov (United States)

    Rosales-Lagarde, Laura; Pasten, Ernesto; Mora, Abrahan; Mahlknecht, Jürgen

    2016-04-01

    Monterrey Metropolitan Area in Nuevo Leon, Mexico, is the third largest metropolitan area and one of the most important industrial sites of Mexico. Groundwater constitutes 40% of the water supply to this urban area. This supply is under constant stress due to the population increase. The unsaturated zone at six sites along two cross-sections was characterized to evaluate the potential of chloride concentration as an indicator of recharge. The selected sites include the range of topographic elevations, vegetation, and annual precipitation of the study area. In each site, boreholes up to 5 m deep were drilled and soil was sampled every 0.5 m. The grain size of each soil sample was determined and pore water extracted to determine the water content percentage, and the chloride, sulfate and nitrate concentration of the pore water. The undersaturated zone consists of alluvial deposits with an average gravel and sand content greater than 60% for all but one of the sampling sites. The pore water content varies from 0.4 to 25% by weight with a decreasing trend as depth increases in areas with agriculture. Sulfate has the highest anion concentration in the pore waters, ranging from 42 to 45,000 mg/L and no apparent distribution pattern along the soil profile columns. Chloride concentration ranges from 8 to 3600 mg/L with an increase in concentration below 1.5 m depth in all the profiles. Chloride and sulfate concentrations with depth are directly correlated suggesting a common input, possibly dissolution-precipitation of evaporite minerals from nearby outcrops or an anthropogenic input. Hence, it is unlikely that chloride behaves as a conservative ion. As a result, its concentration is not likely to be a good indicator of groundwater recharge. Finally; the nitrate concentration ranges from 2 to 96 mg/L nitrate, without a clear pattern along the soil profiles. Low concentration of nitrate in the soil profiles below agricultural areas may suggest denitrification as suggested

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

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-06-01

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

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

    Science.gov (United States)

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

    2007-01-01

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

  19. Groundwater recharge and climatic change during the last 1000 years from unsaturated zone of SE Badain Jaran Desert

    Institute of Scientific and Technical Information of China (English)

    MA Jinzhu; LI Ding; ZHANG Jiawu; W. M. Edmunds; C. Prudhomme

    2003-01-01

    The history of groundwater recharge and climatic changes during the last 1000 years has been estimated and reconstructed using environmental chloride from unsaturated zone profile in the southeast Badain Jaran Desert, NW China. Byusing a steady-state model for duplicate unsaturated zone chloride profiles, the long-term recharge at the site was estimated to be 1.3 mm yr?1. From one profile, which reached the water table, the climatic change events of 10-20 years duration were well preserved. There were 3 wet phases and 4 dry episodes during the recent 800 years according to the peaks and troughs of recharge rate calculated via chloride concentration and moisture content. There was a dry episode before 1290 AD. At ca. 1500-1530 AD, which is an important date, there was an abruptchange from drought to wet conditions. At the beginning of the 1800s, local climate changed from wet to dry occurred and subsequently deteriorated over the past 200 years. The unsaturated profile was compared with the Guliya ice core records. The agreement of wet and dry phases from 1200 to 1900 AD is quite good, whilst trends diverged during the last 100 years. It seems that the large-scale climate difference took place between mountain regions and the desert basin in NW China during the 20th century, which closely correspond to the water table reduction of some 1 metre.

  20. Predicted water-level and water-quality effects of artificial recharge in the Upper Coachella Valley, California, using a finite-element digital model

    Science.gov (United States)

    Swain, Lindsay A.

    1978-01-01

    From 1936 to 1974, water levels declined more than 100 feet in the Palm Springs area and 60 feet in the Palm Desert area of the upper Coachella Valley, Calif. Water from the Colorado River Aqueduct is presently being recharged to the basin. The dissolved-solids concentration of native ground water in the recharge area is about 210 mg/liter and that of recharge water ranges from 600 to 750 mg/liter. A finite-element model indicates that without recharge the 1974 water levels in the Palm Springs area will decline 200 feet by the year 2000 because of pumpage. If the aquifer is recharged at a rate from about 7 ,500 acre-feet per year in 1973 increasing to 61,200 acre-feet per year in 1990 and thereafter, the water level in the Palm Springs area will decline about 20 feet below the 1974 level by 1991 and recover to the 1974 level by 2000. The solute-transport finite-element model of the recharge area indicates that the artificial recharge plume (bounded by the 300-mg/liter line) will move about 1.1 miles downgradient of the recharge ponds by 1981 and about 4.5 miles from the ponds by 2000. (Woodard-USGS)

  1. 工程降水中人工回灌综合技术%Integrated technique of artificial recharge in engineering dewatering

    Institute of Scientific and Technical Information of China (English)

    冶雪艳; 耿冬青; 杜新强; 王福刚; 曹东军

    2011-01-01

    建筑工程降水往往伴生水资源浪费和地面变形等环境问题,人工回灌是解决这些问题的有效手段之一.影响工程降水中人工回灌的条件有回灌场地水文地质条件、回灌水源水质和水量及回灌方案的经济可行性等因素.就工程降水中出现的问题,提出资源补充型回灌和应力稳定型回灌方法,并给出了适用条件;根据工程降水水质特点及现有的地下水人工回灌相关水质标准,提出工程降水回灌水质的控制指标主要为悬浮物、浊度、一般污染性指标、微生物指标及重金属等.针对目前人工回灌在工程中存在的可回灌性低的问题,进行了影响入渗速率因素研究,为今后开展促渗关键技术提供理论支持.%The waste of water resources, ground deformation and other environmental issues are often associated with construction industry dewatering. Artificial recharge is an effective mean to solve these problems. Influential factors of artificial recharge in engineering dewatering are hydrogeological conditions of recharge site, water quality and quantity of recharge and the economic feasibility of recharge program. For the problems in the engineering dewatering, the authors propose two kinds of recharge methods including water resources supplement recharge and stress stable recharge, and propose the applicable conditions. According to the features of construction dewatering and the artificial recharge standards of native grounduater, it was suggested that the water quality control indicators of engineering dewatering are suspended solids, turbidity, general pollution indexes, microbial indexes and heavy metals. Aiming at the problem of low recharge in artificial recharge of construction, the factors that affect the infiltration rate is studied to give theoretical support of the key technology of promotion infiltration in future.

  2. A Deep Percolation Model for Estimating Ground-Water Recharge: Documentation of Modules for the Modular Modeling System of the U.S. Geological Survey

    Science.gov (United States)

    Vaccaro, J.J.

    2007-01-01

    A daily water-budget model for estimating ground-water recharge, the Deep Percolation Model, was modularized for inclusion into the U.S. Geological Survey's Modular Modeling System. The model was modularized in order to facilitate estimation of ground-water recharge under a large range in climatic, landscape, and land-use and land-cover conditions. The model can be applied to areas as large as regions or as small as a field plot. An overview of the Modular Modeling System and the Deep Percolation Model is presented. Data requirements, parameters, and variables for the model are described. The modules that compose the Deep Percolation Model are documented.

  3. Security System of Water Quality for Groundwater Recharge with Infiltration Basin and Reclaimed Water%再生水地表回灌补给地下水的水质安全保障体系

    Institute of Scientific and Technical Information of China (English)

    靳孟贵; 罗泽娇; 梁杏; 鲍建国; 李民敬; 李平

    2012-01-01

    It is significant to ensure safe aquifer recharge using reclaimed water that meets the safety requirement for the sake of recovering aquifer depletion, relieving the conflict between water demand and supply, and controlling the serious environmental pollution in China. To improve the water quality of artificial recharge of groundwater using reclaimed water, we develop a security system of water quality for groundwater recharge with infiltration basin and reclaimed water and key technologies based on a series of experiments and theoretic analysis including the recharge site selection and investigation, higher-efficiency and low-cost wastewater treatment technologies, mathematical models of soil-aquifer system and the design of recharge and pumping schemes, monitoring and controlling system of water quality, safety assessment, regulations and standards, and so on. These key factors are interactive and interdependent. The pilot project in Zhengzhou demonstrates the feasibility of the security system of water quality for groundwater recharge with infiltration basin and reclaimed water, with a two-year operation showing that the water quality of the reclaimed water by the waste water treatment system satisfies the surface recharge requirement in the standard of (GB/T 19772-2005) and is better than that of the original groundwater at the site, and groundwater quality after recharge basically reaches grade III of groundwater quality (GB/T 14818-1993). It is suggested to integrate the use of reclaimed water and artificial recharge of groundwater with the utilization of water resources and environmental protection planning, to make and issue relative laws, regulations and standards, and to establish permission regulation on artificial aquifer recharge as soon as possible so as to promote artificial aquifer recharge using reclaimed water.%把城市污水净化处理为符合回灌标准的再生水并安全回灌补给地下水,对于实现污水资源化、含水层恢复

  4. Using 14C and 3H to delineate a recharge ‘window’ into the Perth Basin aquifers, North Gnangara groundwater system, Western Australia

    International Nuclear Information System (INIS)

    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 (14C and 3H) 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 CO2. 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

  5. Using {sup 14}C and {sup 3}H to delineate a recharge 'window' into the Perth Basin aquifers, North Gnangara groundwater system, Western Australia

    Energy Technology Data Exchange (ETDEWEB)

    Meredith, Karina, E-mail: kmj@ansto.gov.au [Australian Nuclear Science and Technology Organisation, Institute for Environmental Research, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Cendon, Dioni I. [Australian Nuclear Science and Technology Organisation, Institute for Environmental Research, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Pigois, Jon-Philippe [Department of Water, PO Box K822 Perth WA 6842 (Australia); Hollins, Suzanne; Jacobsen, Geraldine [Australian Nuclear Science and Technology Organisation, Institute for Environmental Research, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia)

    2012-01-01

    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 ({approx} 50 m) and is in direct contact with the superficial aquifer, suggesting the possibility of direct recharge into a generally confined aquifer. Environmental isotopes ({sup 14}C and {sup 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{sub 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{sup -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

  6. Prognosis of groundwater recharge by means of the simulation tool PCSiWaPro® under the conditions of climate change

    Science.gov (United States)

    Meyer, M.; Sallwey, J.; Hasan, I.; Graeber, P.-W.

    2012-04-01

    Recent studies showed that varying atmospheric conditions as a result of climate change have a significant impact on the magnitude and time variable development of groundwater recharge. Essentially there are two driving factors that influence groundwater recharge: the temporal distribution of precipitation, and the saturation processes resulting from capillary effects in the unsaturated soil zone. Water balance processes can accurately be modelled by using the Richards' equation for transient flow, together with the Van-Genuchten/Luckner approximation describing hysteresis relationships between water contents and pressure heads in the soil. Precipitation distributions, as boundary conditions for the unsaturated model, can be generated from climate data measurements using statistical analysis tools. These synthetic time series reflect both the real climate conditions in a given model area, as well as statistical variations of rainfall by implementing characteristics of a predefined probability distribution. Depending on the kind of distribution, the resulting time series can represent both annual rainfall variations as well as long-term climate changes. The Institute of Waste Management and Contaminated Site Treatment of the TU Dresden has developed two software programs that help estimate these two driving forces for groundwater recharge. WettGen is a weather generator using a Weibull distribution and Markov chain approximations to create synthetic climate time series. These are applied as an upper boundary condition for PCSiWaPro®, a numerical finite element simulation tool solving the Richards' equation for water balance and a convection dispersion equation for contaminant. The result of this coupled simulation is an outflow at the lower boundary of the PCSiWaPro® model, which can be interpreted as a recharge rate for the underlying aquifer. Considering that climate change scenarios for Germany predict longer dry periods and an increase of extreme precipitation

  7. The uncertainty associated with estimating future groundwater recharge: A summary of recent research and an example from a small unconfined aquifer in a northern humid-continental climate

    Science.gov (United States)

    Kurylyk, Barret L.; MacQuarrie, Kerry T. B.

    2013-06-01

    Global climate models (GCMs) project significant changes to regional and globally-averaged precipitation and air temperature, and these changes will likely have an associated impact on groundwater recharge. A common approach in recent climate change-impact studies is to employ multiple downscaled climate change scenarios to drive a hydrological model and project an envelope of recharge possibilities. However, each step in this process introduces variability into the hydrological results, which translates to uncertainty in the future state of groundwater resources. In this contribution, seven downscaled future climate scenarios for a northern humid-continental climate in eastern Canada were generated from selected combinations of GCMs, emission scenarios, and downscaling approaches. Meteorological data from the climate scenarios and field data from a small unconfined aquifer were used to estimate groundwater recharge with the soil water balance model HELP3. HELP3 simulations for the period 2046-2065 indicated that projected recharge was most sensitive to the selected downscaling/debiasing algorithm and GCM. Projected changes in average annual recharge varied from an increase of 58% to a decrease of 6% relative to the 1961-2000 reference period. Such a large range in projected recharge provides very little useful information regarding the future state of groundwater resources. Additional results from recent comparable studies are compiled and discussed. Based on the results obtained from the present case study and the other studies reviewed, the limitations of current approaches for projecting future recharge are identified, and several suggestions for research opportunities to advance this field are offered.

  8. Distinct groundwater recharge sources and geochemical evolution of two adjacent sub-basins in the lower Shule River Basin, northwest China

    Science.gov (United States)

    Wang, Liheng; Dong, Yanhui; Xie, Yueqing; Song, Fan; Wei, Yaqiang; Zhang, Jiangyi

    2016-08-01

    Based on analysis of groundwater hydrogeochemical and isotopic data, this study aims to identify the recharge sources and understand geochemical evolution of groundwater along the downstream section of the Shule River, northwest China, including two sub-basins. Groundwater samples from the Tashi sub-basin show markedly depleted stable isotopes compared to those in the Guazhou sub-basin. This difference suggests that groundwater in the Tashi sub-basin mainly originates from meltwater in the Qilian Mountains, while the groundwater in the Guazhou sub-basin may be recharged by seepage of the Shule River water. During the groundwater flow process in the Tashi sub-basin, minerals within the aquifer material (e.g., halite, calcite, dolomite, gypsum) dissolve in groundwater. Mineral dissolution leads to strongly linear relationships between Na+ and Cl- and between Mg2++ Ca2+ and SO4 2- + HCO3 -, with stoichiometry ratios of approximately 1:1 in both cases. The ion-exchange reaction plays a dominant role in hydrogeochemical evolution of groundwater in the Guazhou sub-basin and causes a good linear relationship between (Mg2++ Ca2+)-(SO4 2- + HCO3 -) and (Na++ K+)-Cl- with a slope of -0.89 and also results in positive chloroalkaline indices CAI 1 and CAI 2. The scientific results have implications for groundwater management in the downstream section of Shule River. As an important irrigation district in Hexi Corridor, groundwater in the Guazhou sub-basin should be used sustainably and rationally because its recharge source is not as abundant as expected. It is recommended that the surface water should be used efficiently and routinely, while groundwater exploitation should be limited as much as possible.

  9. Improving AVSWAT Stream Flow Simulation by Incorporating Groundwater Recharge Prediction in the Upstream Lesti Watershed, East Java, Indonesia

    Directory of Open Access Journals (Sweden)

    Christina Rahayuningtyas

    2014-01-01

    Full Text Available The upstream Lesti watershed is one of the major watersheds of East Java in Indonesia, covering about 38093 hectares. Although there are enough water resources to meet current demands in the basin, many challenges including high spatial and temporal variability in precipitation from year to year exist. It is essential to understand how the climatic condition affects Lesti River stream flow in each sub basin. This study investigated the applicability of using the Soil and Water Assessment Tool (SWAT with the incorporation of groundwater recharge prediction in stream flow simulation in the upstream Lesti watershed. Four observation wells in the upstream Lesti watershed were used to evaluate the seasonal and annual variations in the water level and estimate the groundwater recharge in the deep aquifer. The results show that annual water level rise was within the 2800 - 5700 mm range in 2007, 3900 - 4700 mm in 2008, 3200 - 5100 mm in 2009, and 2800 - 4600 mm in 2010. Based on the specific yield and the measured water level rise, the area-weighted groundwater predictions at the watershed outlet are 736, 820.9, 786.7, 306.4 mm in 2007, 2008, 2009, and 2010, respectively. The consistency test reveals that the R-square statistical value is greater than 0.7, and the DV (% ranged from 32 - 55.3% in 2007 - 2010. Overall, the SWAT model performs better in the wet season flow simulation than the dry season. It is suggested that the SWAT model needs to be improved for stream flow simulation in tropical regions.

  10. Evaluation of Alternative Conceptual Models Using Interdisciplinary Information: An Application in Shallow Groundwater Recharge and Discharge

    Science.gov (United States)

    Lin, Y.; Bajcsy, P.; Valocchi, A. J.; Kim, C.; Wang, J.

    2007-12-01

    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

  11. Effects of Land-Use Change and Managed Aquifer Recharge on Geochemical Reactions with Implications for Groundwater Quantity and Quality in Atoll Island Aquifers, Roi-Namur, Republic of the Marshall Islands

    Science.gov (United States)

    Hejazian, M.; Swarzenski, P. W.; Gurdak, J. J.; Odigie, K. O.; Storlazzi, C. D.

    2015-12-01

    This study compares the hydrogeochemistry of two contrasting atoll groundwater systems in Roi-Namur, Republic of the Marshall Islands. Roi-Namur houses a U.S. Department of Defense military installation and presents an ideal study location where a human impacted aquifer is co-located next to a natural aquifer as part of two artificially conjoined atoll islands. The hydrogeology and geochemistry of carbonate atoll aquifers has been well studied, particularly because of its small, well-defined hydrologic system that allows for relatively precise modeling. However, it is unknown how changes in land-use/land cover and managed aquifer recharge (MAR) alters natural geochemical processes in atoll aquifers. A better understanding of this has implications on groundwater quantity and quality, carbonate dissolution, and best aquifer management practices in the context of rising sea level and saltwater intrusion. Roi has been heavily modified to house military and civilian operations; here, lack of vegetation and managed recharge has increased the volume of potable groundwater and affected the geochemical processes in the freshwater lens and saltwater transition zone. Namur is heavily vegetated and the hydrogeology is indicative of a natural atoll island. A suite of monitoring wells were sampled across both island settings for major ions, nutrients, trace elements, DOC/DIC, δ13C and δ18O/2H isotopes. By modeling geochemical reactions using a conservative mixing approach, we measure deviations from expected reactions and compare the two contrasting settings using derived geochemical profiles through a wide salinity spectrum. Results indicate that groundwater on Namur is more heavily depleted in δ13C and has greater dissolved inorganic carbon, suggesting higher microbial oxidation and greater dissolution within the carbonate aquifer. This suggests MAR and reduction of vegetation makes the groundwater supply on atoll islands more resilient to sea level rise.

  12. Impacts of Groundwater Recharge from Rubber Dams on the Hydrogeological Environment in Luoyang Basin, China

    Directory of Open Access Journals (Sweden)

    Shaogang Dong

    2014-01-01

    Full Text Available 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.

  13. Impacts of groundwater recharge from rubber dams on the hydrogeological environment in Luoyang Basin, China.

    Science.gov (United States)

    Dong, Shaogang; Liu, Baiwei; Liu, Huamin; Wang, Shidong; Wang, Lixin

    2014-01-01

    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

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

    Science.gov (United States)

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

    2016-04-01

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

  15. Dupuit-Forchheimer theories for the shape of groundwater recharge mounds

    Science.gov (United States)

    Brock, Richard R.

    1991-05-01

    The nonlinear Dupuit-Forchheimer theory and two linearized versions are considered as to their applicability for giving accurate results on recharge mound shapes beneath strip and square basins. Results on mound rises from the approximate theories are compared with those from the nonlinear theory to determine criteria for the use of the approximate theories.

  16. Comparison of groundwater recharge estimation methods for the semi-arid Nyamandhlovu area, Zimbabwe

    NARCIS (Netherlands)

    Sibanda, T.; Nonner, J.C.; Uhlenbrook, S.

    2009-01-01

    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 r

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

    International Nuclear Information System (INIS)

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

  18. Prediction of groundwater quality in recharge areas of pumping wells by simulation models. Solute input into groundwater, solute transport and solute transformation in the aquifer

    International Nuclear Information System (INIS)

    The nitrate input into groundwater from arable land was analyzed. From a sandy soil the 14-year mean concentration in the groundwater recharge was 20, in years with a winter catch crop 14 mg NO3-N/l. Changes in the nitrate content in the rooting zone during winter depend very strongly upon differences in soil and climate. The aquifer of the model area Fuhrberger Feld consists of sandy sediments with an upper denitrification zone and a lower desulfurication zone. The stream-tube model gives first insight into solute concentrations in groundwater and pumped raw water. Case studies with the 2D-vertical model show the dependence of the nitrate and sulfate concentrations from the reserve and distribution of the reduced sulfur compounds. Case studies with a 2D-horizontal model prove, that the stepwise increase of the sulfate concentration in the pumped water from 80 to over 250 mg/l is caused by different periods with conversion of permanent grassland into arable land. (orig.)

  19. Allogenic groundwater recharge to Erenhot Basin%外源地下水补给二连浩特盆地

    Institute of Scientific and Technical Information of China (English)

    陈建生; 王彦超; 谢飞; 徐燚; 陈亚飞; 詹泸成; 江巧宁

    2016-01-01

    In order to identify the source of groundwater recharge in Erenhot, the transforming relationships between atmospheric precipitation, surface water, soil water, and groundwater were studied through isotope geochemical analysis. Due to evaporation, the soil moisture remains lower than the maximum water holding capacity for a long period, and the infiltration of precipitation is not sufficient to change this situation. Compared with precipitation, the soil water is more depleted in deuterium and oxygen isotopes. Through comparison of deuterium and oxygen isotopes in soil water, groundwater, and local precipitation, it was found that the soil water is mainly recharged by groundwater. The isotopic composition of precipitation in the Qiangtang Basin, in Tibet, is similar to that of the groundwater in Erenhot, indicating that the groundwater in the Erenhot Basin is recharged by an allogenic water source. Ankerite, red clay, travertine, siliceous sinter, gypsum, and other minerals are widely distributed in the basalt eruption regions in the Erenhot Basin. Elements such as Fe, Mg, Ca, and Si in these minerals may come from deep-circulating groundwater. The formation of ankerite and red clay indicates that the deep-circulating groundwater goes through a high-temperature process. The allogenic water may come from the seepage of rivers and lakes in the Tibetan Plateau, and the deep-circulating groundwater recharges the groundwater of Erenhot ’ s volcanic basalt areas via volcanic lava pipes. Based on the principle of deep circulation of groundwater, four artesian wells have been drilled near the craters in Erenhot, with the flow capacity of a single well reaching 30 m3/h.%为了查明二连浩特地下水的补给来源,采用同位素地球化学分析方法,研究了二连浩特地区的大气降水、地表水、土壤水与地下水之间的转化关系。结果表明:土壤含水率在蒸发作用下长期处于亏缺状态,入渗降水不足以改变土壤含

  20. Interpretation of groundwater age tracers (CFC-12, 14C, 4He) in a mining-influenced stream-aquifer system with transient recharge dynamics.

    Science.gov (United States)

    Bourke, Sarah; Cook, Peter; Kipfer, Rolf; Dogramaci, Shawan

    2014-05-01

    Interpretation of groundwater age tracers often requires consideration of the mixing of groundwater with varying residence times. Quantification of mixing can be approached through measurement of multiple groundwater age indicators with varying ranges of temporal sensitivity, and their interpretation using lumped parameter models. However, in systems altered by mining, where recharge mechanisms are highly transient in space and time, lumped parameter models do not adequately represent the complexity of the system. In the Pilbara region of Western Australia, water abstracted during dewatering of ore-body aquifers is disposed of by discharging it into ephemeral streams and allowing it to recharge the aquifer. Because this water is essentially being recycled, stable isotopes and chloride are not useful tracers of the impact of this dewatering discharge. In contrast, gas tracers that respond rapidly to exposure to the atmosphere are more useful tracers for constraining the influence of dewatering discharge on the aquifer water balance. In this study we measured CFC-12, 14C and noble gases in production wells and transects of piezometers perpendicular to the stream. Even in samples from wells screened over intervals of 1 m, we observe combinations of tracer concentrations that indicate mixing of groundwater with contrasting residence times. For example, all samples contained measureable CFC-12 concentrations, including those with appreciable terrigenic 4He. Interpretation of these data requires consideration of the history of mining activity in the area. Stream 14C activities, which now range from 50 to 75 pMC, are a function of the dewatering discharge, and are no longer in equilibrium with the atmosphere. As a result, groundwater that recharged prior to mining operations can have higher 14C activities than groundwater that recharged through the stream in the last 10 years. The dewatering discharge has caused the stream to transition from a disconnected ephemeral

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

    Energy Technology Data Exchange (ETDEWEB)

    Czarnecki, J.B. [Geological Survey, Denver, CO (United States); Kroitoru, L. [Roy F. Weston, Inc., Washington, DC (United States); Ronen, D. [Weizmann Inst. of Science, Rehovot (Israel)]|[Hydrological Service, Jerusalem (Israel); Magaritz, M. [Weizmann Inst. of Science, Rehovot (Israel)

    1992-10-01

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

  2. Groundwater recharge processes in the Nasia sub-catchment of the White Volta Basin: Analysis of porewater characteristics in the unsaturated zone

    Science.gov (United States)

    Addai, Millicent Obeng; Yidana, Sandow Mark; Chegbeleh, Larry-Pax; Adomako, Dickson; Banoeng-Yakubo, Bruce

    2016-10-01

    Vertical infiltration of precipitation has been examined in this study for the purpose of evaluating groundwater recharge processes in parts of the Nasia sub-catchment of the White Volta Basin. As recharge is an essential component in the detailed assessment of groundwater resources potential in a basin, evaluating its processes is vital in determining the spatial and temporal variability of the resource. Stable isotope data of precipitation, groundwater, surface water and porewater in the area suggest that the local precipitation is largely enriched compared to global meteoric water. This is consistent with the prevailing local conditions in the region and ties in with observations in other parts of the sub-region. The groundwater and porewater data indicate that prior to, and in the process of infiltration and final percolation into the saturated zone, rainwater undergoes evaporative enrichment such that the finally recharged water plots along an evaporation line with a much shallower gradient and intercept compared to the global meteoric water line and the local meteoric water line. The isotope data further suggest that through the shallow unsaturated zone, a significant fraction of the initial precipitation would have been evaporated by a depth of 3.0 m. Evaporation rates in the range of 38-49% have been estimated for the depth range of 0-3.0 m based on the porewater stable isotope data. Details of the procedures and implications of high evaporation rates within such shallower depths are presented and discussed. Groundwater recharge rates estimated from the chloride mass balance technique report values in the range of 73.26 mm/yr (390 Mm3/yr)-109.89 mm/yr (585.27 Mm3/yr), with an average of 94 mm/yr (500.6 Mm3/yr). These translate into 6.6-10.9% of annual precipitation. Based on the current population trends and per capita water demand of 50 L per capita per day, this study finds that the estimated recharge rates exceed the demand 59 times. This suggests

  3. Water Use, Ground-Water Recharge and Availability, and Quality of Water in the Greenwich Area, Fairfield County, Connecticut and Westchester County, New York, 2000-2002

    Science.gov (United States)

    Mullaney, John R.

    2004-01-01

    Ground-water budgets were developed for 32 small basin-based zones in the Greenwich area of southwestern Connecticut, where crystalline-bedrock aquifers supply private wells, to determine the status of residential ground-water consumption relative to rates of ground-water recharge and discharge. Estimated residential ground-water withdrawals for small basins (averaging 1.7 square miles (mi2) ranged from 0 to 0.16 million gallons per day per square mile (Mgal/d/mi2). To develop these budgets, residential ground-water withdrawals were estimated using multiple-linear regression models that relate water use from public water supply to data on residential property characteristics. Average daily water use of households with public water supply ranged from 219 to 1,082 gallons per day (gal/d). A steady-state finite-difference ground-water-flow model was developed to track water budgets, and to estimate optimal values for hydraulic conductivity of the bedrock (0.05 feet per day) and recharge to the overlying till deposits (6.9 inches) using nonlinear regression. Estimated recharge rates to the small basins ranged from 3.6 to 7.5 inches per year (in/yr) and relate to the percentage of the basin underlain by coarse-grained glacial stratified deposits. Recharge was not applied to impervious areas to account for the effects of urbanization. Net residential ground-water consumption was estimated as ground-water withdrawals increased during the growing season, and ranged from 0 to 0.9 in/yr. Long-term average stream base flows simulated by the ground-water-flow model were compared to calculated values of average base flow and low flow to determine if base flow was substantially reduced in any of the basins studied. Three of the 32 basins studied had simulated base flows less than 3 in/yr, as a result of either ground-water withdrawals or reduced recharge due to urbanization. A water-availability criteria of the difference between the 30-day 2-year low flow and the recharge rate

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2011-12-01

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

  6. Integrating groundwater observations with models of soil-water dynamics to examine recharge patterns through glacial sediments in a humid continental climate

    Science.gov (United States)

    Naylor, S.; Letsinger, S. L.; Ficklin, D. L.; Ellett, K. M.; Olyphant, G. A.; Dufficy, A. L.

    2015-12-01

    Understanding the timing and magnitude of shallow groundwater recharge is critical for determining water balance and analyzing aquifer sensitivity for water resource planning. We analyzed data from six hydrometeorological monitoring stations using HYDRUS 1D to achieve physically based estimates of water-table recharge in various glaciated terrains in Indiana (USA). The models simulated runoff, root-water uptake, and flow through heterogeneous soil profiles to quantify water flux at the water table. Calibration by inverse modeling of data collected in 2013 yielded optimized hydraulic parameters that allowed accurate simulation of observed soil moisture (root mean square error was generally within 3%). The model validation period confirmed accurate simulation of soil moisture as well as correspondence between modeled recharge and observed water-table fluctuations. Additional modelling over a three-year study period indicated that diffuse water-table recharge in the region can be reasonably approximated as 35% of precipitation, but interannual and monthly variability can be significant depending on the glacial setting and pedological development. Soil parent material and horizon characteristics have a strong influence on average annual recharge primarily through their control on Ks, with clay-rich till parent materials producing values as low as 16% and coarse-grained outwash parent materials producing values as high as 58% of precipitation. The combined modelling and monitoring data reveal distinct seasonality of recharge, with most recharge occurring in the winter (seasonal mean of all sites was 66% of precipitation) and lesser but interannually stable amounts in the spring (44%), summer (13%), and autumn (16%). This ongoing research underscores the value of combining vadose zone characterization with hydrometeorological monitoring to more effectively represent how surface energy and moisture budgets influence the dynamics of surface water-groundwater interactions.

  7. Characteristics of Point Recharge in Karst Aquifers

    OpenAIRE

    Nara Somaratne

    2014-01-01

    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...

  8. Multiple tracers of shallow ground-water flow and recharge in hilly loess

    International Nuclear Information System (INIS)

    Vertical profiles of tritium and nitrate pore-water concentrations were determined to ∼8 m depth across two loess hillslopes. Mean recharge fluxes, estimated from chloride mass balance, are 5--10 times larger at the mid- and toe-slope positions than at the top-slope; the magnitudes of the values compare reasonably with results from other methods. The tritium and nitrate profiles exhibit multiple peaks which indicate that piston flow is not the sole flow process in this system. Results of a simple 1-D mixing model suggest that infiltration-exfiltration cycles in zones of plant root activity explain the shallow tritium peaks. Deeper peaks result from preferential vertical and/or lateral flow. The importance of these dispersive processes is underlined by great dilution of observed tritium concentrations, relative to expected concentrations assuming piston flow. In this setting, chloride is useful as a recharge estimator while tritium and nitrate serve as tracers of landscape-scale water movement

  9. Variably-saturated groundwater modeling for optimizing managed aquifer recharge using trench infiltration

    Science.gov (United States)

    Heilweil, Victor M.; Benoit, Jerome; Healy, Richard W.

    2015-01-01

    Spreading-basin methods have resulted in more than 130 million cubic meters of recharge to the unconfined Navajo Sandstone of southern Utah in the past decade, but infiltration rates have slowed in recent years because of reduced hydraulic gradients and clogging. Trench infiltration is a promising alternative technique for increasing recharge and minimizing evaporation. This paper uses a variably saturated flow model to further investigate the relative importance of the following variables on rates of trench infiltration to unconfined aquifers: saturated hydraulic conductivity, trench spacing and dimensions, initial water-table depth, alternate wet/dry periods, and number of parallel trenches. Modeling results showed (1) increased infiltration with higher hydraulic conductivity, deeper initial water tables, and larger spacing between parallel trenches, (2) deeper or wider trenches do not substantially increase infiltration, (3) alternating wet/dry periods result in less overall infiltration than keeping the trenches continuously full, and (4) larger numbers of parallel trenches within a fixed area increases infiltration but with a diminishing effect as trench spacing becomes tighter. An empirical equation for estimating expected trench infiltration rates as a function of hydraulic conductivity and initial water-table depth was derived and can be used for evaluating feasibility of trench infiltration in other hydrogeologic settings

  10. A new method to compute the groundwater recharge for the study of rainfall-triggered deep-seated landslides. Application to the Séchilienne unstable slope (western Alps

    Directory of Open Access Journals (Sweden)

    A. Vallet

    2014-06-01

    Full Text Available 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 accurately estimate the groundwater recharge. In this study, the groundwater recharge is estimated with a soil–water balance based on characterization of evapotranspiration, soil available water capacity and runoff. Although evapotranspiration estimation is a data-demanding method, many landslide sites have limited meteorological datasets. A workflow method is developed to compute daily groundwater recharge. The method requires only temperature and precipitation as inputs. Soil available water capacity and runoff quantities are determined from field observations and spatial datasets using a spatial composite approach before being refined with a sensitivity analysis. The proposed method is developed to be as versatile as possible in order to be readily applied to other landslide sites, and to be sufficiently simple to be used by any specialist who intends to characterise the relationship between rainfall and landslide displacements. Moreover, this method can be applied to any other parameters, as long as these parameters have a relationship with groundwater recharge. This study demonstrates that, for the Séchilienne landslide, the performance of the correlation between rainfall and displacement is significantly improved with groundwater recharge compared to results obtained with precipitation data.

  11. Utilization of artificial recharged effluent as makeup water for industrial cooling system: corrosion and scaling.

    Science.gov (United States)

    Wei, Liangliang; Qin, Kena; Zhao, Qingliang; Noguera, Daniel R; Xin, Ming; Liu, Chengcai; Keene, Natalie; Wang, Kun; Cui, Fuyi

    2016-01-01

    The secondary effluent from wastewater treatment plants was reused for industrial cooling water after pre-treatment with a laboratory-scale soil aquifer treatment (SAT) system. Up to a 95.3% removal efficiency for suspended solids (SS), 51.4% for chemical oxygen demand (COD), 32.1% for Cl(-) and 30.0% SO4(2-) were observed for the recharged secondary effluent after the SAT operation, which is essential for controlling scaling and corrosion during the cooling process. As compared to the secondary effluent, the reuse of the 1.5 m depth SAT effluent decreased the corrosion by 75.0%, in addition to a 55.1% decline of the scales/biofouling formation (with a compacted structure). The experimental results can satisfy the Chinese criterion of Design Criterion of the Industrial Circulating Cooling Water Treatment (GB 50050-95), and was more efficient than tertiary effluent which coagulated with ferric chloride. In addition, chemical structure of the scales/biofouling obtained from the cooling system was analyzed.

  12. Utilization of artificial recharged effluent as makeup water for industrial cooling system: corrosion and scaling.

    Science.gov (United States)

    Wei, Liangliang; Qin, Kena; Zhao, Qingliang; Noguera, Daniel R; Xin, Ming; Liu, Chengcai; Keene, Natalie; Wang, Kun; Cui, Fuyi

    2016-01-01

    The secondary effluent from wastewater treatment plants was reused for industrial cooling water after pre-treatment with a laboratory-scale soil aquifer treatment (SAT) system. Up to a 95.3% removal efficiency for suspended solids (SS), 51.4% for chemical oxygen demand (COD), 32.1% for Cl(-) and 30.0% SO4(2-) were observed for the recharged secondary effluent after the SAT operation, which is essential for controlling scaling and corrosion during the cooling process. As compared to the secondary effluent, the reuse of the 1.5 m depth SAT effluent decreased the corrosion by 75.0%, in addition to a 55.1% decline of the scales/biofouling formation (with a compacted structure). The experimental results can satisfy the Chinese criterion of Design Criterion of the Industrial Circulating Cooling Water Treatment (GB 50050-95), and was more efficient than tertiary effluent which coagulated with ferric chloride. In addition, chemical structure of the scales/biofouling obtained from the cooling system was analyzed. PMID:27191579

  13. An environmental tracers approach to characterize groundwater recharge within a carbonate coastal aquifer (Corse-du-Sud, France)

    Science.gov (United States)

    Garel, Emilie; Huneau, Frederic; Khoumeri, Beatrice; Travi, Yves

    2013-04-01

    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.

  14. Evaluating conceptual modeling frameworks for farm scale groundwater pathogen transport associated with animal farming and municipal wastewater recharge

    Science.gov (United States)

    Cook, S. J.; Li, X.; Watanabe, N.; Atwill, R.; Puente, C. E.; Harter, T.

    2010-12-01

    Land applications to crops of diluted animal manure associated with concentrated animal feeding operations (CAFOs) and field discharges from municipal wastewater treatment plants are potential pathways for the contamination of shallow domestic and agricultural wells by pathogenic microorganisms. Sampling of soil and groundwater for the indicator and pathogenic microorganisms; Enterococcus spp., Escherichia coli, Campylobacter spp. and Salmonella was undertaken at two CAFOs in the San Joaquin Valley, California between 2006 and 2009. Observed concentrations are highly variable in both magnitude and frequency of detection and indicated no clear relationship to field applications or seasonal effects. To investigate if the observed variability in microorganism concentrations in groundwater could be attributed to aquifer heterogeneity, we developed multiple conceptual frameworks employing nonpoint source loading functions and groundwater transport models to simulate a shallow agricultural monitoring well catchment. We developed both, homogenous and heterogeneous aquifer representations, the latter using stochastic transition probability Markov chain representation. Also, we developd homogeneous and spatio-temporally heterogeneous loading models. Model sensitivity to conceptual frameworks, transport parameters, and spatio-temporal variations in diffuse pathogen loading at the water table was determined by comparing simulated frequency of pathogen detection with measured monitoring well breakthrough curves. Model results indicate that field scale aquifer heterogeneity cannot fully account for the variation in concentrations observed in shallow monitoring wells and that microorganism loading at the water table must also be highly heterogeneous. A two dimensional Neyman-Scott cluster process was found to provide the best representation of heterogeneity in recharge concentration and is conceptually consistent with the presence of low attenuation transport pathways in the

  15. BPA-Solicited Technical Review of "Echo Meadows Project Winter Artificial Recharge: Final Report for 2001 Baseline", Technical Report 2004.

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, David

    2004-02-01

    The purpose of this report was to provide, at BPA's request, a technical review of interim products received for Project 2001-015-00 under contract 6925. BPA sometimes solicits technical reviews for Fish and Wildlife products or issues where outside expertise is required. External review of complex project deliverables assures BPA as a funding agency that the contractor is continuing with scientifically-credible experimental techniques envisioned in the original proposal. If the project's methodology proves feasible, there could be potential applications beyond the project area to similar situations in the Columbia Basin. The Experiment involves artificial flooding during high flow periods and a determination of the portion of the return flows that end up in the Umatilla River during low flow months and within acceptable water quality parameters (e.g., low temperature, few contaminants). Flooding could be a critical water source for aquatic organisms at times of the year when flows in the lower reaches of the Umatilla River are low and water is warmer than would be desired. The experiment was proposed to test whether 'this process, recharges the shallow aquifers of the old flood plain, for natural filtration through the alluvial soils as it returns to the Umatilla River, cleaner and cooler (about 50 degree Fahrenheit) five to six month later (about July and August) substantially cooling the river and [making it] more beneficial to anadromous [fish]'. A substantial amount of preliminary data had been collected and preliminary results were submitted in an interim report 'Echo Meadows Project Winter Artificial Recharge: Final Report for 2001 Baseline (December 2002)'. A substantial amount of addition funding was provided for the last cycle of flooding (Phases II) and final analyses of the full compliment of data collected over the life of the contract (Phase III). Third party scientific review may assist the contractor in producing a

  16. Characterize Behaviour of Emerging Pollutants in Artificial Recharge: Column Experiments - Experiment Design and Results of Preliminary Tests

    Science.gov (United States)

    Wang, H.; Carrera, J.; Ayora, C.; Licha, T.

    2012-04-01

    Emerging pollutants (EPs) have been detected in water resources as a result of human activities in recent years. They include pharmaceuticals, personal care products, dioxins, flame retardants, etc. They are a source of concern because many of them are resistant to conventional water treatment, and they are harmful to human health, even in low concentrations. Generally, this study aims to characterize the behaviour of emerging pollutants in reclaimed water in column experiments which simulates artificial recharge. One column set includes three parts: influent, reactive layer column (RLC) and aquifer column (AC). The main influent is decided to be Secondary Effluent (SE) of El Prat Wastewater Treatment Plant, Barcelona. The flow rate of the column experiment is 0.9-1.5 mL/min. the residence time of RLC is designed to be about 1 day and 30-40 days for AC. Both columns are made of stainless steel. Reactive layer column (DI 10cm * L55cm) is named after the filling material which is a mixture of organic substrate, clay and goethite. One purpose of the application of the mixture is to increase dissolve organic carbon (DOC). Leaching test in batchs and columns has been done to select proper organic substrate. As a result, compost was selected due to its long lasting of releasing organic matter (OM). The other purpose of the application of the mixture is to enhance adsorption of EPs. Partition coefficients (Kow) of EPs indicate the ability of adsorption to OM. EPs with logKow>2 could be adsorbed to OM, like Ibuprofen, Bezafibrate and Diclofenac. Moreover, some of EPs are charged in the solution with pH=7, according to its acid dissociation constant (Ka). Positively charged EPs, for example Atenolol, could adsorb to clay. In the opposite, negatively charged EPs, for example Gemfibrozil, could adsorb to goethite. Aquifer column (DI 35cm * L1.5m) is to simulate the processes taking place in aquifer in artificial recharge. The filling of AC has two parts: silica sand and

  17. A multi-tracer approach for assessing the origin, apparent age and recharge mechanism of shallow groundwater in the Lake Nyos catchment, Northwest, Cameroon

    Science.gov (United States)

    Kamtchueng, Brice Tchakam; Fantong, Wilson Yetoh; Wirmvem, Mengnjo Jude; Tiodjio, Rosine Edwige; Fouépé Takounjou, Alain; Asai, Kazuyoshi; Bopda Djomou, Serges L.; Kusakabe, Minoru; Ohba, Takeshi; Tanyileke, Gregory; Hell, Joseph Victor; Ueda, Akira

    2015-04-01

    The shallow aquifer in the vicinity of Lake Nyos (Northwest, Cameroon) is one of the main water supply sources to meet the water needs of the inhabitants to be resettled after 1986s tragedy. Unfortunately, there is a lack of knowledge on the groundwater recharge and flow systems in the area. Multiple environmental tracers (δ18O, δD, Cl-, CFCs and SF6) and a yearly record of rainfall, surface waters and groundwater were employed to characterize the recharge mechanism of the shallow groundwater seeping in the fractured rock of the Lake Nyos catchment (LNC). The δ18O-δD relationship of the rainfall events gave the Nyos Meteoric Water Line: δD = 8.28 δ18O + 11.87. Inland moisture vapor may have impacted the isotopic composition of original vapor masses from Gulf of Guinea prior to precipitation. Shallow groundwater in the LNC shows a similar trend of enrichment in 18O and D as surface waters indicating a well-mixed aquifer. The proportions of surface waters and rainfall in the groundwater reservoir were 87% and 13%, respectively. The high annual recharge rate (941 mm/yr) and the seasonal variability in the isotopic signatures of groundwater indicate a renewable aquifer system. CFCs apparent ages-based piston flow model revealed a young age (average of 24 a.) of the groundwater in the LNC. SF6-based ages were biased young as compared to relatively younger than CFCs-based ages, implying an additional terrigenic production of SF6. The conceptual model for groundwater flow suggests that three main flow regimes, mainly controlled by the physical properties of the rock heterogeneities govern the movement of water in the aquifer. The piston flow model appears, however, to be the better model to explain the flow regime in the highly faulted and fissured area where recharge occurs (∼1200-1600 masl). The rapid circulation and the low solubility lead to low mineralization. In the middle-lower area where waters circulate more in the weathered layer, exponential mixing

  18. Management of Groundwater Recharge Areas in the Mouth of Weber Canyon

    OpenAIRE

    Clyde, Calvin G.; Duffy, Christopher J.; Fisk, Edward P.; Hoggan, Daniel H.; Hansen, David E.

    1984-01-01

    Proper management of surface and groundwater resources is important for their prolonged and a beneficial use. Within the Weber Delta area there has existed a continual decline in the piezometric surface of the deep confined aquifer over the last 40 years. This decline ranges from approximately 20 feet along the eastern shore of the Great Salt Lake to 50 feet along in the vicinity of Hill Air Force Base. Declines i...

  19. Comparative review and synthesis of ground-water recharge estimates for the Great Bend Prairie aquifer of Kansas

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — In this report I briefly outline the importance of and difficulties involved in estimating aquifer recharge and compare reported recharge estimates for the Great...

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

    Science.gov (United States)

    Oden, Timothy D.; Truini, Margot

    2013-01-01

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

  1. EQUITY IN DISTRIBUTION OF BENEFITS FROM WATER HARVESTING AND GROUNDWATER RECHARGE – AN ECONOMIC STUDY IN SUJALA WATERSHED PROJECT IN KARNATAKA

    OpenAIRE

    Seema, H.M.; Chandrakanth, Mysore G.; Nagaraj, N.

    2008-01-01

    In this study, economic impact of water harvesting and groundwater recharging was analyzed in the context of Sujala watershed equity and efficiency in the distribution of benefits in Chitradurga district, Karnataka. Field data for 2004-05 (drought year) and 2005-06 (normal year) from 30 sample farmers in Sujala watershed form the data base for the study. Another sample of 30 farmers from Non-Sujala (or DPAP) watershed, and 30 from outside watershed area form the control. Farmers were further ...

  2. Optimal groundwater remediation using artificial neural networks and the genetic algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, L.L.

    1992-08-01

    An innovative computational approach for the optimization of groundwater remediation is presented which uses artificial neural networks (ANNs) and the genetic algorithm (GA). In this approach, the ANN is trained to predict an aspect of the outcome of a flow and transport simulation. Then the GA searches through realizations or patterns of pumping and uses the trained network to predict the outcome of the realizations. This approach has advantages of parallel processing of the groundwater simulations and the ability to ``recycle`` or reuse the base of knowledge formed by these simulations. These advantages offer reduction of computational burden of the groundwater simulations relative to a more conventional approach which uses nonlinear programming (NLP) with a quasi-newtonian search. Also the modular nature of this approach facilitates substitution of different groundwater simulation models.

  3. Optimal groundwater remediation using artificial neural networks and the genetic algorithm

    International Nuclear Information System (INIS)

    An innovative computational approach for the optimization of groundwater remediation is presented which uses artificial neural networks (ANNs) and the genetic algorithm (GA). In this approach, the ANN is trained to predict an aspect of the outcome of a flow and transport simulation. Then the GA searches through realizations or patterns of pumping and uses the trained network to predict the outcome of the realizations. This approach has advantages of parallel processing of the groundwater simulations and the ability to ''recycle'' or reuse the base of knowledge formed by these simulations. These advantages offer reduction of computational burden of the groundwater simulations relative to a more conventional approach which uses nonlinear programming (NLP) with a quasi-newtonian search. Also the modular nature of this approach facilitates substitution of different groundwater simulation models

  4. Steady-state groundwater recharge in trapezoidal-shaped aquifers: A semi-analytical approach based on variational calculus

    Science.gov (United States)

    Mahdavi, Ali; Seyyedian, Hamid

    2014-05-01

    This study presents a semi-analytical solution for steady groundwater flow in trapezoidal-shaped aquifers in response to an areal diffusive recharge. The aquifer is homogeneous, anisotropic and interacts with four surrounding streams of constant-head. Flow field in this laterally bounded aquifer-system is efficiently constructed by means of variational calculus. This is accomplished by minimizing a properly defined penalty function for the associated boundary value problem. Simple yet demonstrative scenarios are defined to investigate anisotropy effects on the water table variation. Qualitative examination of the resulting equipotential contour maps and velocity vector field illustrates the validity of the method, especially in the vicinity of boundary lines. Extension to the case of triangular-shaped aquifer with or without an impervious boundary line is also demonstrated through a hypothetical example problem. The present solution benefits from an extremely simple mathematical expression and exhibits strictly close agreement with the numerical results obtained from Modflow. Overall, the solution may be used to conduct sensitivity analysis on various hydrogeological parameters that affect water table variation in aquifers defined in trapezoidal or triangular-shaped domains.

  5. Biotransformation of trace organic chemicals during groundwater recharge: How useful are first-order rate constants?

    KAUST Repository

    Regnery, J.

    2015-05-29

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Dipankar, E-mail: dsaha002@yahoo.com [Central Ground Water Board, Ministry of water Resources, Govt of India, Lok Nayak Bhawan, Patna 800001 (India); Sinha, U.K. [Isotope Application Division, Bhaba Atomic Research Center, Mumbai 400085 (India); Dwivedi, S.N. [Central Ground Water Board, Ministry of water Resources, Govt of India, Lok Nayak Bhawan, Patna 800001 (India)

    2011-04-15

    Research highlights: {yields} Sub-regional scale aquifers delineated in arsenic-enriched belt in the Ganga Plain. Isotopic fingerprint of the groundwater, from arsenic-enriched and arsenic-safe aquifers established for the first time in the Ganga Plain. {yields} Recharge processes and the water provenances of vertically separated Quaternary aquifers have been established. {yields} Mean residence time of groundwater in the deeper aquifers has been worked out using C-14 isotope. {yields} Water from the deeper aquifer has been correlated with the paleoclimatic model of the Middle Ganga Plain (Mid-Ganga Basin) for 6-2 ka. - Abstract: Arsenic concentrations in groundwater extracted from shallow aquifers in some areas of the Ganga Plain in the states of Bihar and Uttar Pradesh, exceed 50 {mu}g L{sup -1} and locally reach levels in the 400 {mu}g L{sup -1} range. The study covered 535 km{sup 2} of active flood plain of the River Ganga, in Bihar where a two-tier aquifer system has been delineated in a multi-cyclic sequence of Quaternary sand, clay, sandy clay and silty clay all {<=}{approx}250 m below ground surface. The research used isotopic signatures ({delta}{sup 18}O, {delta}{sup 2}{Eta}, {sup 3}H, {sup 14}C) and major chemical constituents (HCO{sub 3}{sup -},SO{sub 4}{sup 2-},NO{sub 3}{sup -},Cl{sup -},Ca{sup 2+},Mg{sup 2+},Na{sup +},K{sup +},As{sub total}) of groundwater to understand the recharge processes and groundwater circulation in the aquifers. Values of {delta}{sup 18}O and {delta}{sup 2}{Eta} combined with {sup 3}H data indicate that the recharge to the As-enriched top 40 m of the deposits is modern (<50 a), predominantly meteoric, with some evaporation during infiltration, and partly from tanks and other surface water bodies. The lower part of the upper aquifer is vulnerable to mobilization of As with increasing groundwater extraction. The low As lower aquifer (max. 5 {mu}g L{sup -1}) is hydrologically isolated from the upper aquifer and is characterized by

  7. Dynamic Vulnerability of Karst Systems: a Concept to understand qualitative and quantitative Aspects of Karst springs due to Changes in Groundwater Recharge

    Science.gov (United States)

    Huggenberger, P.; Butscher, C.; Epting, J.; Auckenthaler, A.

    2015-12-01

    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

  8. Soil-Water Balance (SWB) model estimates of soil-moisture variability and groundwater recharge in the South Platte watershed, Colorado

    Science.gov (United States)

    Anderson, A. M.; Walker, E. L.; Hogue, T. S.; Ruybal, C. J.

    2015-12-01

    Unconventional energy production in semi-arid regions places additional stress on already over-allocated water systems. Production of shale gas and oil resources in northern Colorado has rapidly increased since 2010, and is expected to continue growing due to advances in horizontal drilling and hydraulic fracturing. This unconventional energy production has implications for the availability of water in the South Platte watershed, where water demand for hydraulic fracturing of unconventional shale resources reached ~16,000 acre-feet in 2014. Groundwater resources are often exploited to meet water demands for unconventional energy production in regions like the South Platte basin, where surface water supply is limited and allocated across multiple uses. Since groundwater is often a supplement to surface water in times of drought and peak demand, variability in modeled recharge estimates can significantly impact projected availability. In the current work we used the Soil-Water Balance Model (SWB) to assess the variability in model estimates of actual evapotranspiration (ET) and soil-moisture conditions utilized to derive estimates of groundwater recharge. Using both point source and spatially distributed data, we compared modeled actual ET and soil-moisture derived from several potential ET methods, such as Thornthwaite-Mather, Jense-Haise, Turc, and Hargreaves-Samani, to historic soil moisture conditions obtained through sources including the Gravity Recovery and Climate Experiment (GRACE). In addition to a basin-scale analysis, we divided the South Platte watershed into sub-basins according to land cover to evaluate model capabilities of estimating soil-moisture parameters with variations in land cover and topography. Results ultimately allow improved prediction of groundwater recharge under future scenarios of climate and land cover change. This work also contributes to complementary subsurface groundwater modeling and decision support modeling in the South Platte.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-04-15

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

  10. Spatial Distribution of Ground-Water Recharge Estimated with a Water-Budget Method for the Jordan Creek Watershed, Lehigh County, Pennsylvania

    Science.gov (United States)

    Risser, Dennis W.

    2008-01-01

    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

  11. Preliminary assessment of potential well yields and the potential for artificial recharge of the Elm and Middle James aquifers in the Aberdeen area, South Dakota

    Science.gov (United States)

    Emmons, P.J.

    1987-01-01

    A complex hydrologic system exists in the glacial drift overlying the bedrock in the Aberdeen, South Dakota, area. The hydrologic system has been subdivided into three aquifers: the Elm, Middle James, and Deep James. These sand-and-gravel outwash aquifers generally are separated from each other by till or other fine-grained sediments. The Elm aquifer is the uppermost and largest of the aquifers and underlies about 204 sq mi of the study area. The maximum altitude of the top of the Elm aquifer is 1,400 ft and the minimum altitude of the bottom is 1,225 ft. The Middle James aquifer underlies about 172 sq mi of the study area. The maximum altitude of the top of the Middle James aquifer is 1,250 ft and the minimum altitude of the bottom is 1 ,150 ft. The lower-most Deep James aquifer was not evaluated. The quality of the water from the Elm and Middle James aquifer varies considerably throughout the study area. The predominant chemical constituents in the water from the aquifers are sodium and sulfate ions; however, calcium, magnesium, bicarbonate, or chloride may dominate locally. The calculated theoretical total well yield from the Elm and Middle James aquifers ranges from a minimum of 64 cu ft/sec, which may be conservative, to a maximum of 640 cu ft/sec. Based on available data, yields of 100 to 150 cu ft/sec probably can be obtained from properly sited and constructed wells. The feasibility of artificially recharging an aquifer, using the technique of water spreading, depends on the geologic and hydraulic characteristics of the aquifer and of the sediments overlying the aquifer through which the recharge water must percolate. The sites suitable for artificial recharge in the study area were defined as those areas where the average aquifer thickness was > 20 ft and the average thickness of the fine-grained sediments overlying the aquifer was < 10 ft. Using these criteria, about 14 sq mi of the study area are suitable for artificial recharge. Infiltration rates in

  12. Sensitivity analysis of groundwater level in Jinci Spring Basin (China) based on artificial neural network modeling

    Science.gov (United States)

    Li, Xian; Shu, Longcang; Liu, Lihong; Yin, Dan; Wen, Jinmei

    2012-06-01

    Jinci Spring in Shanxi, north China, is a major local water source. It dried up in April 1994 due to groundwater overexploitation. The groundwater system is complex, involving many nonlinear and uncertain factors. Artificial neural network (ANN) models are statistical techniques to study parameter nonlinear relationships of groundwater systems. However, ANN models offer little explanatory insight into the mechanisms of prediction models. Sensitivity analysis can overcome this shortcoming. In this study, a back-propagation neural network model was built based on the relationship between groundwater level and its sensitivity factors in Jinci Spring Basin; these sensitivity factors included precipitation, river seepage, mining drainage, groundwater withdrawals and lateral discharge to the associated Quaternary aquifer. All the sensitivity factors were analyzed with Garson's algorithm based on the connection weights of the neural network model. The concept of "sensitivity range" was proposed to describe the value range of the input variables to which the output variables are most sensitive. The sensitivity ranges were analyzed by a local sensitivity approach. The results showed that coal mining drainage is the most sensitive anthropogenic factor, having a large effect on groundwater level of the Jinci Spring Basin.

  13. Existence of Heterogeneity Aquifer by Groundwater Response to Tidal Fluctuation in Artificial Islands

    Science.gov (United States)

    Huang, Y. L.; Lin, H. R.; Chen, Y. L.; Huang, S. Y.; Wen, J. C.

    2015-12-01

    This research focuses on the estimation of the heterogeneous aquifer for artificial islands by using the numerical modeling. The study area of this experiment is located in the Sixth Naphtha Cracker Plant, which is beside the estuary of the Jhuoshuei River in the western parts of Taiwan. The island is approximately 22.55 Square kilometers and although, the geology is consisted mostly of sandy soil, the hydraulic conductivity is heterogeneous based on the slug test results. Due to the fact that the study area is an island, the groundwater level is affected by the sea tidal; therefore, 10 observation wells for monitoring the groundwater level have been set and the observation frequency has been taken hourly for a period of seven months. In addition to that, for estimating the heterogeneity hydrogeology distribution field on artificial islands, the technique of inversing and verifying the Virtual Experimental Field (VEF) of the heterogeneity hydrogeology distribution field by using the Monte Carlo method is applied. To complete the experiment, the inverse technique in the study area of the heterogeneity hydrogeology distribution field is followed under the same methods. The purpose of this study is to introduce and estimate the heterogeneous unconfined aquifer for artificial islands, based on the groundwater response to the tidal fluctuation.

  14. Assessing groundwater recharge in an Andean closed basin using isotopic characterization and a rainfall-runoff model: Salar del Huasco basin, Chile

    Science.gov (United States)

    Uribe, Javier; Muñoz, José F.; Gironás, Jorge; Oyarzún, Ricardo; Aguirre, Evelyn; Aravena, Ramón

    2015-11-01

    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.

  15. Investigating plantation-induced near-surface soil hydrophobicity and its impact on groundwater recharge in the Nebraska Sand Hills, USA

    Science.gov (United States)

    Adane, Z. A.; Nasta, P.; Gates, J. B.

    2014-12-01

    Although numerous studies in diverse environmental settings have demonstrated that plantations tend to reduce soil moisture and recharge rates, research on physical mechanisms affecting these linkages tend to focus mainly on the effects of evapotranspiration and interception. This study investigates the extent of soil hydrophobicity resulting from land use changes and its impact on groundwater recharge in a century-old experimental forest surrounded by grassland in the Northern High Plains (Nebraska National Forest). Water Drop Penetration Tests (WDPT) and Nuclear Magnetic Resonance (NMR) spectroscopy were used to investigate soil hydrophobicity on 50 cm soil cores collected from experimental plots beneath 5 land cover types. WDPT analysis indicated that most near-surface soils (0-12.5 and 12.5-25 cm) beneath pine plots were moderately to strongly hydrophobic. NMR spectroscopy analysis comparing ratios of hydrophobic (3.2-0.5 and 8.5-6.5 ppm) to hydrophilic (6.5-3.2 ppm) regions suggests that surface soils beneath the plantations were uniformly more hydrophobic than grasslands (by ~30 to 260%). Unsaturated zone soil cores were collected from beneath each experimental plot for comparison of hydrophobicity with recharge rates based on chloride and sulfate mass balance. Recharge estimates beneath the plantations (4-10 mm yr-1) represent reductions of 86-94% relative to the surrounding native grassland, suggesting a link between soil hydrophobicity and reduced infiltration beneath the plantations.

  16. Sensitivity of mGROWA-simulated groundwater recharge to changes in soil and land use parameters in a Mediterranean environment and conclusions in view of ensemble-based climate impact simulations.

    Science.gov (United States)

    Ehlers, L; Herrmann, F; Blaschek, M; Duttmann, R; Wendland, F

    2016-02-01

    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. PMID:25980930

  17. Dual-porosity modeling of groundwater recharge: testing a quick calibration using in situ moisture measurements, Areuse River Delta, Switzerland

    Science.gov (United States)

    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

  18. Recharge-induced groundwater flow over a plane sloping bed: Solutions for steady and transient flow using physical and numerical models

    Science.gov (United States)

    Chapman, T. G.

    2005-07-01

    The free surface profile and outflow hydrograph for groundwater under conditions of steady uniform recharge followed by recession have been studied in viscous fluid model tests, using a sloping bed with a gradient of 0.2. The data have been compared with the nonlinear Boussinesq model and a modification of that model simulating the outflow seepage surface, obtained from a finite difference solution of the free boundary problem. It is shown that for a given bed slope, there is close to a linear relationship between outflow and storage raised to a power n, where n ranges from almost 2 for zero slopes to just above 1 at a gradient of 0.3. There is also a simple relationship between outflow and storage in the final stage of recession, when a drainage front occurs on the bed. These results lead to simple algorithms for prediction of the outflow under unsteady recharge conditions.

  19. Simulation of streamflow, evapotranspiration, and groundwater recharge in the lower San Antonio River Watershed, South-Central Texas, 2000-2007

    Science.gov (United States)

    Lizarraga, Joy S.; Ockerman, Darwin J.

    2010-01-01

    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

  20. Geochemistry and isotope evolution of groundwater and recharge mechanisms at a uranium production centre in the semi-arid region of Caetite-BA, Brazil: Implications for groundwater management

    International Nuclear Information System (INIS)

    The semi-arid region of the northeast of Brazil is characterized by a lack of superficial waters due to low precipitation and high evaporation rates. Due to these adverse climatic conditions, intense pressure is being put on the use of groundwater resources. However, there is still insufficient knowledge about the aquifer system which is causing an overexploitation of the water resources. Groundwater is pumped from a fractured, crystalline aquifer of low productivity, where wells show generally yield rates lower than 3 m3 · h-1. The study was carried out in a semi-arid area located in the centre-south region of Bahia State at an elevation of 900 m a.s.L, where were discovered several radioactive anomalies by aerogeophysical surveys performed during the 1970s, that give origin to the uranium province named Lagoa Real.The research approach included isotopic and geochemical analysis of groundwater sampled from 25 wells placed in crystalline rock areas (granite or gneiss) covered by thin layers of residual soil or alluvial sediments. Groundwater is Na-HCO3 type water and relative high concentrations of Cl and SO4- are observed in some groundwater.The stable isotope data (δH and δ18O) showed that evaporation plays a role in the salinization of groundwater.The radiocarbon ages, corrected by carbonate dissolution (through δ13C and DIC), showed very young waters that were recently recharged, perhaps during the last few decades These data discard the possibility that groundwater salinization was caused by discharge of deeper saline groundwater through faults associated to a regional groundwater flow system. The presence of an active shallow groundwater flow system offers better possibility for sustainable use of the groundwater resources in this semi-arid region of Brazil. (author)

  1. 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

    Science.gov (United States)

    Bartos, Timothy T.; Ogle, Kathy Muller

    2002-01-01

    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

  2. The use of unsaturated zone solutes and deuterium profiles in the study of groundwater recharge in the semi-arid zone of Nigeria

    International Nuclear Information System (INIS)

    Two unsaturated zone profiles (MF and MG) in NE Nigeria have been sampled for inert tracers (Cl, Br, NO3 and δ2H to investigate recharge rates and processes. The upper MF and MG profiles have sandy lithology, lower moisture content (2H around -30 per mille. All these indicate that present day recharge is taking place. The lower section of the MF profile shows a distinct contrast with high moisture content (up to 27%), very high chloride (average 2892 mg/L) and relatively enriched deuterium (-12 per mille), indicating the effect of evaporative enrichment. This lower section corresponds to low permeability lacustrine deposits probably representing the former bed of Lake Chad where little or no infiltration has been occurring since the mid-Holocene when the lake extended over this area. The sand-covered areas of the Sahel of the NE Nigeria provide an important phreatic aquifer. An estimation of the amount of recharge using the unsaturated zone chloride mass balance gives significant rates of 14 mm/a and 22 mm/a for the upper MF and MG profiles respectively. These rates mainly span the period of the recent Sahel drought and even higher recharge rates may occur during wetter periods. These rates fall within the 14 mm/a to 53 mm/a range estimated for the Manga Grasslands area in the NE Nigeria obtained in an earlier study. From the water resource point of view, the region has potential for perennially-recharged groundwater resources that can sustain the present abstraction level which is mainly via dug wells. (author)

  3. Extensive aquifer recharge through atmospheric chloride deposition on the land by means of groundwater from penetrating wells

    OpenAIRE

    Custodio Gimena, Emilio; Alcalá García, Francisco J.

    2011-01-01

    Aquifer recharge is essential to evaluate aquifer renewable water resources for water studies and management. However this is one of the most difficult issues in hydrogeology. In order to get reasonable results, as many different appropriate techniques as possible should be used. The most used ones for total diffuse recharge are those relying on soil water balance. In order to check the evaluations, the use of other independent methods is advisable, even if they are simple ones. The chlori...

  4. Identification of key factors governing chemistry in groundwater near the water course recharged by reclaimed water at Miyun County, Northern China

    Institute of Scientific and Technical Information of China (English)

    Yilei Yu; Xianfang Song; Yinghua Zhang; Fandong Zheng; Ji Liang; Dongmei Han; Ying Ma

    2013-01-01

    Reclaimed water was successfully used to recover the dry Chaobai River in Northern China,but groundwater may be polluted.To ensure groundwater protection,it is therefore critical to identify the governing factors of groundwater chemistry.Samples of reclaimed water,river and groundwater were collected monthly at Chaobai River from January to September in 2010.Fifteen water parameters were analyzed.Two kinds of reclaimed water were different in type (Na-Ca-Mg-C1-HCO3 or Na-Ca-Cl-HCO3) and concentration of nitrogen.The ionic concentration and type in river were similar to reclaimed water.Some shallow wells near the river bed had the same type (Na-Ca-Mg-Cl-HCO3) and high concentration as reclaimed water,but others were consistent with the deep wells (Ca-Mg-HCO3).Using cluster analysis,the 9 months were divided into two periods (dry and wet seasons),and all samples were grouped into several spatial clusters,indicating different controlling mechanisms.Principal component analysis and conventional ionic plots showed that calcium,magnesium and bicarbonate were controlled by water-rock interaction in all deep and some shallow wells.This included the dissolution of calcite and carbonate weathering.Sodium,potassium,chloride and sulfate in river and some shallow wells recharged by river were governed by evaporation crystallization and mixing of reclaimed water.But groundwater chemistry was not controlled by precipitation.During the infiltration of reclaimed water,cation exchange took place between (sodium,potassium) and (calcium,magnesium).Nitrification and denitrification both happened in most shallow groundwater,but only denitrification in deep groundwater.

  5. Evaluation of nitrate removal effect on groundwater using artificial neural networks

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Considering the non-linear, complex and multivariable process of biological denitrification, an activated sludge process was introduced to remove nitrate in groundwater with the aid of artificial neural networks(ANN) to evaluate the nitrate removal effect. The parameters such as COD, NH3-N, NO3--N, NO2--N, MLSS,DO, etc. , were used for input nodes, and COD , NH3 -N , NO3--N , NO2--N were selected for output nodes. Experimental ANN training results show that ANN was able to predict the output water quality parameters very well. Most of relative errors of NO3--N and COD were in the range of ± 10% and ±5% respectively. The results predicted by ANN model of nitrate removal in groundwater produced good agreement with the experimental data. Though ANN model can optimize effect of the whole system, it cannot replace the water treatment process.

  6. Demonstrating trend reversal of groundwater quality in relation to time of recharge determined by 3H/3He

    NARCIS (Netherlands)

    Visser, A.; Broers, H.P.; Grift, B. van der; Bierkens, M.F.P.

    2007-01-01

    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 i

  7. Quantification and regionalization of groundwater recharge in South-Central Kansas: Integrating field characterization, statistical analysis, and GIS

    Science.gov (United States)

    Sophocleous, M.

    2000-01-01

    A practical methodology for recharge characterization was developed based on several years of field-oriented research at 10 sites in the Great Bend Prairie of south-central Kansas. This methodology combines the soil-water budget on a storm-by-storm year-round basis with the resulting watertable rises. The estimated 1985-1992 average annual recharge was less than 50mm/year with a range from 15 mm/year (during the 1998 drought) to 178 mm/year (during the 1993 flood year). Most of this recharge occurs during the spring months. To regionalize these site-specific estimates, an additional methodology based on multiple (forward) regression analysis combined with classification and GIS overlay analyses was developed and implemented. The multiple regression analysis showed that the most influential variables were, in order of decreasing importance, total annual precipitation, average maximum springtime soil-profile water storage, average shallowest springtime depth to watertable, and average springtime precipitation rate. Therefore, four GIS (ARC/INFO) data "layers" or coverages were constructed for the study region based on these four variables, and each such coverage was classified into the same number of data classes to avoid biasing the results. The normalized regression coefficients were employed to weigh the class rankings of each recharge-affecting variable. This approach resulted in recharge zonations that agreed well with the site recharge estimates. During the "Great Flood of 1993," when rainfall totals exceeded normal levels by -200% in the northern portion of the study region, the developed regionalization methodology was tested against such extreme conditions, and proved to be both practical, based on readily available or easily measurable data, and robust. It was concluded that the combination of multiple regression and GIS overlay analyses is a powerful and practical approach to regionalizing small samples of recharge estimates.

  8. Attenuation capacity of a coastal aquifer under managed recharge by reclaimed wastewater

    Science.gov (United States)

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

    2013-08-01

    Managed Aquifer Recharge (MAR) is becoming an increasingly attractive water management option, especially in semiarid areas. Nevertheless, field studies on the fate and transport of priority substances, heavy metals and pharmaceutical products within the recharged aquifer are rare. Based on the above, the objective of this project is to study the hydrological conditions of the coastal aquifer of Ezousa (Cyprus) and its ability to attenuate pollutants. The Ezousa riverbed is a locally important aquifer used for a MAR project where treated effluent from the Paphos Waste Water Treatment Plant is recharged into the aquifer through a number of artificial ponds along the riverbed. Additionally, groundwater is pumped for irrigation purposes from wells located nearby. The hydrological conditions of the area are unique due to the construction of the Kannaviou dam in 2005 that reduced natural recharge of the Ezousa aquifer significantly, inducing the saltwater intrusion phenomenon. A three-dimensional finite element model of the area was constructed using the FEFLOW software to simulate the groundwater flow conditions and transport of Phosphorous and cooper in the subsurface from the recharge process. The model was calibrated using hydraulic head and chemical data for the time period of 2002-2011. The groundwater model was coupled with a geochemical model PHREEQC attempting to evaluate nitrate and Copper processes. Inverse modeling calculation was used to determine sets of moles transfers of phases that are attributed to the water composition change in groundwater between the mixture of natural groundwater and reclaimed wastewater and the final water composition.

  9. Characteristics of Point Recharge in Karst Aquifers

    Directory of Open Access Journals (Sweden)

    Nara Somaratne

    2014-09-01

    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.

  10. Effects of recharge and discharge on delta2H and delta18O composition and chloride concentration of high arsenic/fluoride groundwater from the Datong Basin, northern China.

    Science.gov (United States)

    Xie, Xianjun; Wang, Yanxin; Su, Chunli; Duan, Mengyu

    2013-02-01

    To better understand the effects of recharge and discharge on the hydrogeochemistry of high levels of arsenic (As) and fluoride (F) in groundwater, environmental isotopic composition (delta2H and delta18O) and chloride (Cl) concentrations were analyzed in 29 groundwater samples collected from the Datong Basin. High arsenic groundwater samples (As > 50 micog/L) were found to be enriched in lighter isotopic composition that ranged from -92 to -78 per thousand for deuterium (delta2H) and from -12.5 to -9.9 per thousand for oxygen-18 (delta18O). High F-containing groundwater (F > 1 mg/L) was relatively enriched in heavier isotopic composition and varied from -90 to -57 per thousand and from -12.2 to -6.7 per thousand for delta2H and delta18O, respectively. High chloride concentrations and delta18O values were primarily measured in groundwater samples from the northern and southwestern portions of the study area, indicating the effect of evaporation on groundwater. The observation of relatively homogenized and low delta18O values and chloride concentrations in groundwater samples from central part of the Datong Basin might be a result of fast recharge by irrigation returns, which suggests that irrigation using arsenic-contaminated groundwater affected the occurrence of high arsenic-containing groundwater in the basin.

  11. Effects of recharge and discharge on delta2H and delta18O composition and chloride concentration of high arsenic/fluoride groundwater from the Datong Basin, northern China.

    Science.gov (United States)

    Xie, Xianjun; Wang, Yanxin; Su, Chunli; Duan, Mengyu

    2013-02-01

    To better understand the effects of recharge and discharge on the hydrogeochemistry of high levels of arsenic (As) and fluoride (F) in groundwater, environmental isotopic composition (delta2H and delta18O) and chloride (Cl) concentrations were analyzed in 29 groundwater samples collected from the Datong Basin. High arsenic groundwater samples (As > 50 micog/L) were found to be enriched in lighter isotopic composition that ranged from -92 to -78 per thousand for deuterium (delta2H) and from -12.5 to -9.9 per thousand for oxygen-18 (delta18O). High F-containing groundwater (F > 1 mg/L) was relatively enriched in heavier isotopic composition and varied from -90 to -57 per thousand and from -12.2 to -6.7 per thousand for delta2H and delta18O, respectively. High chloride concentrations and delta18O values were primarily measured in groundwater samples from the northern and southwestern portions of the study area, indicating the effect of evaporation on groundwater. The observation of relatively homogenized and low delta18O values and chloride concentrations in groundwater samples from central part of the Datong Basin might be a result of fast recharge by irrigation returns, which suggests that irrigation using arsenic-contaminated groundwater affected the occurrence of high arsenic-containing groundwater in the basin. PMID:23472327

  12. Coastal groundwater table estimation by an elevation fluctuation neural model

    Institute of Scientific and Technical Information of China (English)

    HE Bin; WANG Yi

    2007-01-01

    Restrictions of groundwater management are often derived from the insufficient or missing groundwater database. A suitable and complete groundwater database will allow sound engineering plans for sustainable water usage, including the drilling of wells, rates of water withdrawal, and eventually artificial recharge of the aquifer. The spatial-temporal variations of groundwater monitoring data are fluently influenced by the presence of manual factors, monitor equipment malfunctioning, natural phenomena, etc. Thus, it is necessary for researchers to check and infill the groundwater database before running the numerical groundwater model. In this paper, an artificial neural network (ANN)-based model is formulated using the hydrological and meteorological data to infill the inadequate data in the groundwater database. Prediction results present that ANN method could be a desirable choice for estimating the missing groundwater data.

  13. Species specific temporal patterns of throughfall and stemflow in deciduous and coniferous forests with implications for unsaturated zone and groundwater recharge processes

    Science.gov (United States)

    Dreibrodt, Janek; Hopp, Luisa; Germer, Sonja; Morgner, Markus; Güntner, Andreas; Blume, Theresa

    2015-04-01

    The extent of rainfall redistribution by forest canopies and resulting spatial patterns vary for different tree species and can play an important role for soil moisture distribution and subsequently for groundwater recharge. A thorough understanding of these relationships will improve our ability to predict future impacts of climate and forest structural changes on the water balance of forest stands. Therefore we quantified the fractions of throughfall and stemflow per gross rainfall for different forest types and for different meteorological conditions and rainfall characteristics. Throughfall was continuously measured at 7 sites with different dominant tree species and ages: young and old beech, young oak, and young and old pine. Within 2000m²-plots situated in the Müritz-Nationalpark (north-eastern Germany), trough-based throughfall monitoring systems with a total collecting area of 6.6m² per site, and soil moisture, leaf wetness and sapflow sensors were installed. Stemflow was measured for 5-10 trees per site with a temporal resolution of 1min. Canopy structure is likely to have a major influence on the throughfall distribution. Therefore, the forest structure was characterized by a detailed mapping of tree species, stem positions and stem diameters. Seasonal variations of leaf coverage were monitored by ground-based leaf-area index (LAI) measurements. Evaporation from the canopy is the sum of evaporation during rainfall events and of precipitation stored in the canopy that is evaporated after rainfall ceased. We estimated the storage capacity of the canopy based on the cumulative precipitation between the onset of rainfall and the onset of throughfall. The influence of rainfall intensity and leaf wetness before the onset of rainfall events on canopy storage was also assessed. The data set was used to parameterize and run the soil hydrological model HYDRUS-2D at various spatial scales to assess the effect of stemflow and throughfall patterns on the dynamics

  14. Residence times and mixing of water in river banks: implications for recharge and groundwater-surface water exchange

    Science.gov (United States)

    Unland, N. P.; Cartwright, I.; Cendón, D. I.; Chisari, R.

    2014-12-01

    Bank exchange processes within 50 m of the Tambo River, southeast Australia, have been investigated through the combined use of 3H and 14C. Groundwater residence times increase towards the Tambo River, which suggests the absence of significant bank storage. Major ion concentrations and δ2H and δ18O values of bank water also indicate that bank infiltration does not significantly impact groundwater chemistry under baseflow and post-flood conditions, suggesting that the gaining nature of the river may be driving the return of bank storage water back into the Tambo River within days of peak flood conditions. The covariance between 3H and 14C indicates the leakage and mixing between old (~17 200 years) groundwater from a semi-confined aquifer and younger groundwater (<100 years) near the river, where confining layers are less prevalent. It is likely that the upward infiltration of deeper groundwater from the semi-confined aquifer during flooding limits bank infiltration. Furthermore, the more saline deeper groundwater likely controls the geochemistry of water in the river bank, minimising the chemical impact that bank infiltration has in this setting. These processes, coupled with the strongly gaining nature of the Tambo River are likely to be the factors reducing the chemical impact of bank storage in this setting. This study illustrates the complex nature of river groundwater interactions and the potential downfall in assuming simple or idealised conditions when conducting hydrogeological studies.

  15. Areas contributing recharge to production wells and effects of climate change on the groundwater system in the Chipuxet River and Chickasheen Brook Basins, Rhode Island

    Science.gov (United States)

    Friesz, Paul J.; Stone, Janet R.

    2015-01-01

    The Chipuxet River and Chickasheen Brook Basins in southern Rhode Island are an important water resource for public and domestic supply, irrigation, recreation, and aquatic habitat. The U.S. Geological Survey, in cooperation with the Rhode Island Department of Health, began a study in 2012 as part of an effort to protect the source of water to six large-capacity production wells that supply drinking water and to increase understanding of how climate change might affect the water resources in the basins. Soil-water-balance and groundwater-flow models were developed to delineate the areas contributing recharge to the wells and to quantify the hydrologic response to climate change. Surficial deposits of glacial origin ranging from a few feet to more than 200 feet thick overlie bedrock in the 24.4-square mile study area. These deposits comprise a complex and productive aquifer system.

  16. Effectiveness of basin morphometry, remote sensing, and applied geosciences on groundwater recharge potential mapping: a comparative study within a small watershed

    Science.gov (United States)

    Roy, Suvendu; Sahu, Abhay Sankar

    2016-06-01

    A multidisciplinary approach using the integrated field of geosciences (e.g., geomorphology, geotectonics, geophysics, and hydrology) is established to conduct groundwater recharge potential mapping of the Kunur River Basin, India. The relative mean error (RME) calculation of the results of three applied techniques and water table data from twenty-four observation wells in the basin over the 2000-2010 period are presented. Nine subbasins were identified and ranked for the RME calculation, where the observation wells-based ranking was taken as standard order for comparison. A linear model has been developed using six factors (drainage density, surface slope, ruggedness index, lineament density, Bouguer gravity anomaly, and potential maximum water retention capacity) and a grid-wise weighted index. In a separate comparative approach, the sub-basin and grid-wise analyses have been conducted to identify the suitable spatial unit for watershed level hydrological modeling.

  17. Estimating the role of a ditch network in groundwater recharge in a Mediterranean catchment using a water balance approach

    OpenAIRE

    Dages, C.; Voltz, Marc; Bsaibes, A.; Prévot, L.; Huttel, O.; Louchart, X.; Garnier, F.; Negro, S.

    2009-01-01

    Water balance variables were monitored in a farmed Mediterranean catchment characterized by a dense ditch network to allow for the separate estimation of the diffuse and concentrated recharge terms during flood events. The 27 ha central part of the catchment was equipped with (i) rain gauges, (ii) ditch gauge stations, (iii) piezometers, (iv) neutron probes, and (v) an eddy covariance mast including a 3D sonic anemometer and a fast hygrometer. The water balance was calculated for two autumnal...

  18. 城市化对地下水补给的影响 ——以石家庄市为例%The Impact of Urbanization on Groundwater Recharge: a Case Study of Shijiazhuang City

    Institute of Scientific and Technical Information of China (English)

    于开宁

    2001-01-01

    城市化对地下水补给的影响对研究城市水循环、水资源供需平衡及地下水超采、防治地下水水质恶化,以及揭示两大主要地下水环境问题(地下水超采与水质恶化)之间的有机联系都具有重要意义。石家庄城市化与地下水之间的相互作用机理研究具有典型示范性。本文以石家庄市为例,在分析地下水在城市供水中的作用及其开发利用基础上,通过研究城市化影响地下水补给的变化规律,进一步探讨了城市化对地下水补给的影响机理,最终建立城市化影响下地下水补给增量的诱发机理框图。研究结果表明,城市化会导致地下水补给量的增加;地下水开采诱发产生对城市周围井场和地表水的袭夺以及城市供、排水系统渗漏所造成的新补给源的引入是城市化诱发产生地下水补给增量的重要机理。%With the rapid urbanization, groundwater has been playing a more and more important role. The study on the impact of urbanization upon groundwater recharge is of great significance not only in studying the hydrologic cycle, supply-demand balance and groundwater overexploitation but also in preventing and controlling the deterioration of groundwater quality and in revealing the relationship between overexploitation and water quality deterioration, the two main problems in groundwater environment. The study on the interaction mechanism between urbanization and groundwater constitutes a typical example. In this paper, based on the analysis of the importance of groundwater in water supply of the city as well as the exploitation and utilization of groundwater, the author studied the change of groundwater recharge under the impact of urbanization, and then discussed the impact mechanism of urbanization on groundwater recharge. On such a basis, a frame-figure on the mechanism inducing the increment of groundwater recharge was constructed. The results show:① urbanization

  19. Comparison of Groundwater Level Models Based on Artificial Neural Networks and ANFIS

    Directory of Open Access Journals (Sweden)

    Nevenka Djurovic

    2015-01-01

    Full Text Available Water table forecasting plays an important role in the management of groundwater resources in agricultural regions where there are drainage systems in river valleys. The results presented in this paper pertain to an area along the left bank of the Danube River, in the Province of Vojvodina, which is the northern part of Serbia. Two soft computing techniques were used in this research: an adaptive neurofuzzy inference system (ANFIS and an artificial neural network (ANN model for one-month water table forecasts at several wells located at different distances from the river. The results suggest that both these techniques represent useful tools for modeling hydrological processes in agriculture, with similar computing and memory capabilities, such that they constitute an exceptionally good numerical framework for generating high-quality models.

  20. Comparison of Groundwater Level Models Based on Artificial Neural Networks and ANFIS.

    Science.gov (United States)

    Djurovic, Nevenka; Domazet, Milka; Stricevic, Ruzica; Pocuca, Vesna; Spalevic, Veli