WorldWideScience

Sample records for aquifers

  1. Aquifers

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This map layer contains the shallowest principal aquifers of the conterminous United States, Hawaii, Puerto Rico, and the U.S. Virgin Islands, portrayed as...

  2. Alluvial Aquifer

    Data.gov (United States)

    Kansas Data Access and Support Center — This coverage shows the extents of the alluvial aquifers in Kansas. The alluvial aquifers consist of unconsolidated Quaternary alluvium and contiguous terrace...

  3. Mississippian aquifers

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the extent of the Mississippian aquifers in the states of Pennsylvania, Ohio, West Virginia, Virginia, Kentucky, Tennessee, Alabama,...

  4. Ozark Aquifer

    Data.gov (United States)

    Kansas Data Access and Support Center — These digital maps contain information on the altitude of the base and top, the extent, and the potentiometric surface of the Ozark aquifer in Kansas. The Ozark...

  5. EPA Sole Source Aquifers

    Data.gov (United States)

    U.S. Environmental Protection Agency — Information on sole source aquifers (SSAs) is widely used in assessments under the National Environmental Policy Act and at the state and local level. A national...

  6. Lower Cretaceous aquifers

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the extent of the Lower Cretaceous aquifers in the states of Montana, Wyoming, South Dakota, Kansas, Nebraska, Iowa, and Minnesota..

  7. Mississippi embayment aquifer system

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the extent of the Mississippi embayment aquifer system in the states of Louisiana, Arkansas, Mississippi, Alabama, Tennessee, and Kentucky.

  8. Early Mesozoic basin aquifers

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the extent of the Early Mesozoic basin aquifers in the states of Massachusettes, Connecticut, New York, New Jersey, Pennsylvania, Maryland,...

  9. Ogallala Aquifer Mapping Program

    International Nuclear Information System (INIS)

    A computerized data file has been established which can be used efficiently by the contour-plotting program SURFACE II to produce maps of the Ogallala aquifer in 17 counties of the Texas Panhandle. The data collected have been evaluated and compiled into three sets, from which SURFACE II can generate maps of well control, aquifer thickness, saturated thickness, water level, and the difference between virgin (pre-1942) and recent (1979 to 1981) water levels. 29 figures, 1 table

  10. Specific yield, High Plains aquifer

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents specific-yield ranges in the High Plains aquifer of the United States. The High Plains aquifer underlies 112.6 million acres...

  11. Aquifer stability investigations

    Energy Technology Data Exchange (ETDEWEB)

    Allen, R.D.; Doherty, T.J.

    1981-09-01

    The study of compressed air energy storage (CAES) in porous rock reservoirs is carried out within the Reservoir Stability Studies Program at Pacific Northwest Laboratory. The goal of the study is to establish criteria for long-term stability of aquifer CAES reservoirs. These criteria are intended to be guidelines and check lists that utilities and architect-engineering firms may use to evaluate reservoir stability at candidate CAES sites. These criteria will be quantitative where possible, qualitative where necessary, and will provide a focal point for CAES relevant geotechnical knowledge, whether developed within this study or available from petroleum, mining or other geotechnical practices using rock materials. The Reservoir Stability Studies Program had four major activities: a state-of-the-art survey to establish preliminary stability criteria and identify areas requiring research and development; numerical modeling; laboratory testing to provide data for use in numerical models and to investigate fundamental rock mechanics, thermal, fluid, and geochemical response of aquifer materials; and field studies to verify the feasibility of air injection and recovery under CAES conditions in an aquifer, to validate and refine the stability criteria, and to evaluate the accuracy and adequacy of the numerical and experimental methodologies developed in previous work. Three phases of study, including preliminary criteria formulation, numerical model development, and experimental assessment of CAES reservoir materials have been completed. Present activity consists of construction and operation of the aquifer field test, and associated numerical and experimental work in support of that activity. Work is presently planned to be complete by 1983 at the end of the field test. At that time the final stability criteria for aquifers will be issued. Attached here also are preliminary criteria for aquifers.

  12. Sole Source Aquifers for NY and NJ

    Data.gov (United States)

    U.S. Environmental Protection Agency — This layer is the designated sole source aquifers of New York and New Jersey. A Sole Source Aquifer, is an aquifer that supplies 50% or more of the drinking water...

  13. High Temperature Aquifer Storage

    Science.gov (United States)

    Ueckert, Martina; Niessner, Reinhard; Baumann, Thomas

    2016-04-01

    Combined heat and power generation (CHP) is highly efficient because excess heat is used for heating and/or process energy. However, the demand of heat energy varies considerably throughout the year while the demand for electrical energy is rather constant. It seems economically and ecologically highly beneficial for municipalities and large power consumers such as manufacturing plants to store excess heat in groundwater aquifers and to recuperate this energy at times of higher demand. Within the project High Temperature Aquifer Storage, scientists investigate storage and recuperation of excess heat energy into the bavarian Malm aquifer. Apart from high transmissivity and favorable pressure gradients, the hydrochemical conditions are crucial for long-term operation. An enormous technical challenge is the disruption of the carbonate equilibrium - modeling results indicated a carbonate precipitation of 10 - 50 kg/d in the heat exchangers. The test included five injection pulses of hot water (60 °C up to 110 °C) and four tracer pulses, each consisting of a reactive and a conservative fluorescent dye, into a depth of about 300 m b.s.l. resp. 470 m b.s.l. Injection and production rates were 15 L/s. To achieve the desired water temperatures, about 4 TJ of heat energy were necessary. Electrical conductivity, pH and temperature were recorded at a bypass where also samples were taken. A laboratory container at the drilling site was equipped for analysing the concentration of the dyes and the major cations at sampling intervals of down to 15 minutes. Additional water samples were taken and analysed in the laboratory. The disassembled heat exchanger prooved that precipitation was successfully prevented by adding CO2 to the water before heating. Nevertheless, hydrochemical data proved both, dissolution and precipitation processes in the aquifer. This was also suggested by the hydrochemical modelling with PhreeqC and is traced back to mixture dissolution and changing

  14. Mississippi River Valley alluvial aquifer

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the extent of the Mississippi River Valley alluvial aquifer in the states of Missouri, Kentucky, Tennessee, Arkansas, Mississippi, and...

  15. (SUPERCEDED) High Plains aquifer (SUPERCEDED)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the extent of the High Plains aquifer in the states of South Dakota, Wyoming, Nebraska, Colorado, Kansas, New Mexico, Oklahoma, and Texas....

  16. Southeastern Coastal Plain aquifer system

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the extent of the Southeastern Coastal Plain aquifer system in Kentucky, Tennessee, Mississippi, Alabama, Georgia, and South Carolina.

  17. Region 9 Sole Source Aquifers

    Data.gov (United States)

    U.S. Environmental Protection Agency — There are 7 polygons representing 6 individual sole source aquifer boundaries and one streamflow source area in California, Arizona, and Nevada. Various efforts...

  18. Digital data sets that describe aquifer characteristics of the Enid isolated terrace aquifer in northwestern Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digitized aquifer boundaries for the Enid isolated terrace aquifer in northwestern Oklahoma. The Enid isolated terrace aquifer covers...

  19. Digital data sets that describe aquifer characteristics of the Elk City aquifer in western Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digitized aquifer boundaries for the Elk City aquifer in western Oklahoma. The aquifer covers an area of approximately 193,000 acres and...

  20. Microbial dynamics in natural aquifers

    OpenAIRE

    Bajracharya, Bijendra Man

    2016-01-01

    Microorganisms in groundwater form ecosystems that can transform chemical compounds. Quantitatively understanding microbial dynamics in soils and groundwater is thus essential for pollutant dynamics and biogeochemistry in the subsurface. This dissertation addresses three factors influencing microbial dynamics in aquifers and soils, namely: (1) the influence of grazing on bacteria in eutrophic aquifers, posing the question whether the carrying capacity of bacteria, which has been observed i...

  1. Saturated thickness, High Plains aquifer, 2009

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents the saturated thickness of the High Plains aquifer of the United States, 2009, in feet. The High Plains aquifer underlies...

  2. As contamination in Mercedes aquifer groundwater

    International Nuclear Information System (INIS)

    This work is about the quality of the groundwater an the arsenic content in different aquifers in Uruguay. The first data obtained of arsenic concentrations are from subterranes water in the Mercedes aquifers

  3. National Sole Source Aquifer GIS Layer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This data set contains indexes and Esri shape files of boundaries of the designated sole source aquifers and related aquifer boundaries. Data provide a vector...

  4. Interconnectivity between the Superficial Aquifer and the Deep Confined Aquifers of the Gnangara Mound, Western Australia

    International Nuclear Information System (INIS)

    Perth groundwater resources are obtained from three major aquifers that occur beneath the Perth metropolitan area: the Superficial aquifer, Leederville aquifer and Yarragadee aquifer. Each aquifer has a unique seasonal water level pattern controlled by soils, geomorphology and geology. Land use is mainly responsible for variations in recharge; however, the hydraulic properties control aquifer response and water level pattern to a greater degree. Groundwater in the three aquifers is generally of very good quality except in localised areas. Salinity increases with depth and in direction of groundwater flow in the three aquifers. The best water quality is in the Superficial aquifer in the Wanneroo well field area. The geochemistry and stable isotope signatures from the three major aquifers revealed distinct water types that suggest very little hydraulic connection or mixing of waters between these aquifers at the present abstraction and recharge regimes. The results also show that the Leederville and Yarragadee aquifers were recharged during earlier cooler times while the Superficial aquifer is being recharged at present

  5. Digital data sets that describe aquifer characteristics of the Enid isolated terrace aquifer in northwestern Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digitized water-level elevation contours for the Enid isolated terrace aquifer in northwestern Oklahoma. The Enid isolated terrace aquifer...

  6. Digital data sets that describe aquifer characteristics of the Central Oklahoma aquifer in central Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digitized aquifer boundaries created for a previously published report about the Central Oklahoma aquifer in central Oklahoma. This area...

  7. Digital data sets that describe aquifer characteristics of the Elk City aquifer in western Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digitized polygons of constant recharge values for the Elk City aquifer in western Oklahoma. The aquifer covers an area of approximately...

  8. Digital data sets that describe aquifer characteristics of the High Plains aquifer in western Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital aquifer boundaries for the High Plains aquifer in western Oklahoma. This area encompasses the panhandle counties of Cimarron,...

  9. Digital data sets that describe aquifer characteristics of the Antlers aquifer in southeastern Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digitized aquifer boundaries of the Antlers aquifer in southeastern Oklahoma. The Early Cretaceous-age Antlers Sandstone is an important...

  10. Digital data sets that describe aquifer characteristics of the Rush Springs aquifer in western Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digitized aquifer boundaries for the Rush Springs aquifer in western Oklahoma. This area encompasses all or part of Blaine, Caddo,...

  11. Digital data sets that describe aquifer characteristics of the Elk City aquifer in western Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digitized water-level elevation contours for the Elk City aquifer in western Oklahoma. The aquifer covers an area of approximately 193,000...

  12. Digital data sets that describe aquifer characteristics of the Elk City aquifer in western Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digitized polygons of constant hydraulic conductivity values for the Elk City aquifer in western Oklahoma. The aquifer covers an area of...

  13. Digital data sets that describe aquifer characteristics of the Tillman terrace and alluvial aquifer in southwestern Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital aquifer boundaries for the Tillman terrace and alluvial aquifer in southwestern Oklahoma. The Tillman terrace aquifer encompasses...

  14. Digital data sets that describe aquifer characteristics of the Vamoosa-Ada aquifer in east-central Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digitized aquifer boundaries for the Vamoosa-Ada aquifer in east-central Oklahoma. The Vamoosa-Ada aquifer is an important source of water...

  15. VULNERABILITY OF KARST AQUIFERS TO CHEMICAL CONTAMINATION

    Science.gov (United States)

    Ground water flow in karst aquifers is very different from flow in granular or fractured aquifers. arst ground water flow is often turbulent within discrete conduits that are convergent in the upper reaches and divergent in the lower, simulating discharge to one or more springs. ...

  16. Geohydrology of the Cerro Prieto geothermal aquifer

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez R, J.; de la Pena L, A.

    1981-01-01

    The most recent information on the Cerro Prieto geothermal aquifer is summarized, with special emphasis on the initial production zone where the wells completed in the Alpha aquifer are located. These wells produce steam for power plant units 1 and 2. Brief comments also are made on the Beta aquifer, which underlies the Alpha aquifer in the Cerro Prieto I area and which extends to the east to what is known as the Cerro Prieto II and Cerro Prieto III areas. The location of the area studied is shown. The Alpha and Beta aquifers differ in their mineralogy and cementing mineral composition, temperatures, and piezometric levels. The difference in piezometric levels indicates that there is no local communication between the two aquifers. This situation has been verified by a well interference test, using well E-1 as a producer in the Beta aquifer and well M-46 as the observation well in the Alpha aquifer. No interference between them was observed. Information on the geology, geohydrology, and geochemistry of Cerro Prieto is presented.

  17. Geochemistry of the Arbuckle-Simpson Aquifer

    Science.gov (United States)

    Christenson, Scott; Hunt, Andrew G.; Parkhurst, David L.; Osborn, Noel I.

    2009-01-01

    The Arbuckle-Simpson aquifer in south-central Oklahoma provides water for public supply, farms, mining, wildlife conservation, recreation, and the scenic beauty of springs, streams, and waterfalls. A new understanding of the aquifer flow system was developed as part of the Arbuckle-Simpson Hydrology Study, done in 2003 through 2008 as a collaborative research project between the State of Oklahoma and the Federal government. The U.S. Geological Survey collected 36 water samples from 32 wells and springs in the Arbuckle-Simpson aquifer in 2004 through 2006 for geochemical analyses of major ions, trace elements, isotopes of oxygen and hydrogen, dissolved gases, and dating tracers. The geochemical analyses were used to characterize the water quality in the aquifer, to describe the origin and movement of ground water from recharge areas to discharge at wells and springs, and to determine the age of water in the aquifer.

  18. Economics of Managed Aquifer Recharge

    Directory of Open Access Journals (Sweden)

    Robert G. Maliva

    2014-05-01

    Full Text Available Managed aquifer recharge (MAR technologies can provide a variety of water resources management benefits by increasing the volume of stored water and improving water quality through natural aquifer treatment processes. Implementation of MAR is often hampered by the absence of a clear economic case for the investment to construct and operate the systems. Economic feasibility can be evaluated using cost benefit analysis (CBA, with the challenge of monetizing benefits. The value of water stored or treated by MAR systems can be evaluated by direct and indirect measures of willingness to pay including market price, alternative cost, value marginal product, damage cost avoided, and contingent value methods. CBAs need to incorporate potential risks and uncertainties, such as failure to meet performance objectives. MAR projects involving high value uses, such as potable supply, tend to be economically feasible provided that local hydrogeologic conditions are favorable. They need to have low construction and operational costs for lesser value uses, such as some irrigation. Such systems should therefore be financed by project beneficiaries, but dichotomies may exist between beneficiaries and payers. Hence, MAR projects in developing countries may be economically viable, but external support is often required because of limited local financial resources.

  19. Recharge from rectangular areas to finite aquifers

    Science.gov (United States)

    Rao, N. H.; Sarma, P. B. S.

    1981-10-01

    A generalized analytical solution is derived for the growth of groundwater mound in finite aquifers bounded by open water bodies, in response to recharge from rectangular areas. Finite Fourier transforms are used to solve the linearized differential equation of groundwater flow. Unlike earlier solutions, the method presented here does not require the use of tables for evaluation of complicated functions. The solution is evaluated by comparison with existing numerical and analytical results. In stream-aquifer systems similar to those described above, application of the proposed solution is more realistic than using solutions available for infinite aquifers.

  20. Volcanic and sedimentary-rock aquifers

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the extent of the Volcanic and sedimentary-rock aquifers in the states of Montana, Wyoming, Idaho, Nevada, California, Oregon, and...

  1. Hydrogeology - MO 2014 Thermoclines Ozark Aquifer (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Ozark Aquifer thermo cline correlates the temperature data throughout the state in the Ordovician System and the Upper Cambrian Series, consisting of the Eminence...

  2. Aquifer vulnerability for Colorado and New Mexico

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey Data Series provides raster data representing an estimate of aquifer vulnerability calculated for each 30-meter raster cell. Depth to...

  3. Hydrogeologic characterization of devonian aquifers in Uruguay

    International Nuclear Information System (INIS)

    This article carried out the assistance research project implementation in devonian sedimentary units as a potentials aquifers and their best use to school supplying and rural population in central area of Uruguay.

  4. Nitrate reduction in an unconfined sandy aquifer

    DEFF Research Database (Denmark)

    Postma, Diederik Jan; Boesen, Carsten; Kristiansen, Henning;

    1991-01-01

    in the reduced zone of the aquifer are organic matter, present as reworked brown coal fragments from the underlying Miocene, and small amounts of pyrite at an average concentration of 3.6 mmol/kg. Electron balances across the redoxcline, based on concentrations of O2, NO3-, SO4(2-) and total inorganic carbon......Nitrate distribution and reduction processes were investigated in an unconfined sandy aquifer of Quaternary age. Groundwater chemistry was studied in a series of eight multilevel samplers along a flow line, deriving water from both arable and forested land. Results show that plumes of nitrate......-contaminated groundwater emanate from the agricultural areas and spread through the aquifer. The aquifer can be subdivided into an upper 10- to 15-m thick oxic zone that contains O2 and NO3-, and a lower anoxic zone characterized by Fe2+-rich waters. The redox boundary is very sharp, which suggests that reduction...

  5. As contamination in Mercedes (Uruguay) aquifer groundwater

    International Nuclear Information System (INIS)

    The study presents data on the concentration of arsenic in groundwater aquifer Mercedes, where the highest concentration area is located in New Palmira.A geological formation decryption of the Mercedes for the Upper Cretaceous is made.

  6. North Atlantic Coastal Plain aquifer system

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the extent of the North Atlantic Coastal Plain aquifer system in North Carolina, Virginia, Maryland, Deleware, and New Jersey.

  7. Improving Aquifer Thermal Energy Storage Efficiency

    OpenAIRE

    S. Kranz; G. Blöcher; Ali Saadat

    2015-01-01

    Aquifer thermal energy storage systems play an important role for the future energy supply systems. Such systems can decouple energy availability (e.g. fluctuating renewable energy, waste heat) and energy supply in times of demand. In order to fully contribute to the sustainability of energy supply, the essential requirements of energy storages are high energy efficiency, high reliability, cost effectiveness, as well as operational flexibility. Aquifer Thermal Energy Storage Systems (ATES) me...

  8. Basement Aquifers : How Useful Are Gravity Data ?

    Science.gov (United States)

    Genthon, P.; Mouhouyouddine, A. H.; Hinderer, J.; Hector, B.; Yameogo, S.

    2014-12-01

    Gravity data with a few microgal precision were proved to be able to constrain the specific yield of various kinds of aquifer in West Africa from annual fluctuations of both the gravimetric and piezometric signals (Pfeffer et al., Geophys. J. Int., 2011; Hector et al., Geophys. J. Int., 2013). However some recent papers reported a disappointing potential of gravity measurements during a pumping experiment in a sandy aquifer (Blainey et al., WRR, 2007; Herckenrath et al., WRR, 2012) and their poor ability in constraining the transmissity and specific yield of the aquifer, which are the parameters to which pumping tests give access. Fresh basement rocks present generally a null porosity and the structure of basement aquifers is given by the weathering profile. In tropical climate, this profile consists of a few tens meter thick saprolite layer, with noticeable porosity but low permeability overlying the weathering front. This weathering front includes in many instances a fractured medium and presents a high permeability with variable porosity. It is hardly sampled in coring experiments. We present some numerical simulation results on the ability of gravity to constrain the transmissivity of this medium. Due to poroelasticity of clay minerals in the saprolite, soil subsidence is expected to occur during pumping with a significant gravity effect. Gravity measurements have therefore to be completed with leveling data at a millimetric precision. We present first the results of numerical modeling of the gravity and subsidence for a theoretical horizontally stratified basement aquifer, and show that gravity and leveling are able to provide independently the poroelasticity coefficient and a single transmissivity coefficient for the bottom of the aquifer, if the properties of the upper saprolites are known. We will discuss then the general case, where the aquifer presents a vertical fracture where the weathering profile thickens.

  9. Multidepth pumping tests in deep aquifers.

    Science.gov (United States)

    Alam, N; Olsthoorn, T N

    2014-09-01

    Multidepth pumping tests (MDPTs), in which different sections of a screen are pumped in sequence, are not being used by hydrogeologists, despite the capability of such tests to resolve uncertainties in the estimation of aquifer characteristics. MDPTs can be used to discern the effects of partial penetration and vertical anisotropy. This article demonstrates the use of MDPTs for a deep and vertically anisotropic aquifer, based on a real and unique series of pumping tests conducted in the Indus Basin. Traditional single-layer methods, which incorporate partial penetration and vertical scaling, were employed to evaluate these tests. However, the drawdowns of the 19 piezometers at different depths for which times series data were available could not be matched, presumably because of the layered structure of the aquifer. Numerical (MODFLOW) and multilayer analytical (Hemker and Maas 1987; Hemker 1999) approaches were used to assess the benefits of using MDPTs in the analysis of deep layered and anisotropic aquifers. The multilayer analytical solution results are consistent with the measured and numerically computed drawdowns. The original step-drawdown data were used to verify the model independently. The results of statistical analyses indicate that the parameters for a three-layer system are uniquely estimated. A sensitivity analysis showed that aquifer depths greater than 900 m do not affect the drawdown. The multilayer analytical solution was implemented in MATLAB and can be found in the online version of this article. This multilayer analytical approach was implemented in MLU by Hemker and Randall (2013) for up to 40 layers. The results of this study will be useful in groundwater management, exploration, and optimal well depth estimation for the Indus Basin aquifer and other vertically heterogeneous aquifers. PMID:24428328

  10. A Black Hills-Madison Aquifer origin for Dakota Aquifer groundwater in northeastern Nebraska.

    Science.gov (United States)

    Stotler, Randy; Harvey, F Edwin; Gosselin, David C

    2010-01-01

    Previous studies of the Dakota Aquifer in South Dakota attributed elevated groundwater sulfate concentrations to Madison Aquifer recharge in the Black Hills with subsequent chemical evolution prior to upward migration into the Dakota Aquifer. This study examines the plausibility of a Madison Aquifer origin for groundwater in northeastern Nebraska. Dakota Aquifer water samples were collected for major ion chemistry and isotopic analysis ((18)O, (2)H, (3)H, (14)C, (13)C, (34)S, (18)O-SO(4), (87)Sr, (37)Cl). Results show that groundwater beneath the eastern, unconfined portion of the study area is distinctly different from groundwater sampled beneath the western, confined portion. In the east, groundwater is calcium-bicarbonate type, with delta(18)O values (-9.6 per thousand to -12.4 per thousand) similar to local, modern precipitation (-7.4 per thousand to -10 per thousand), and tritium values reflecting modern recharge. In the west, groundwater is calcium-sulfate type, having depleted delta(18)O values (-16 per thousand to -18 per thousand) relative to local, modern precipitation, and (14)C ages 32,000 to more than 47,000 years before present. Sulfate, delta(18)O, delta(2)H, delta(34)S, and delta(18)O-SO(4) concentrations are similar to those found in Madison Aquifer groundwater in South Dakota. Thus, it is proposed that Madison Aquifer source water is also present within the Dakota Aquifer beneath northeastern Nebraska. A simple Darcy equation estimate of groundwater velocities and travel times using reported physical parameters from the Madison and Dakota Aquifers suggests such a migration is plausible. However, discrepancies between (14)C and Darcy age estimates indicate that (14)C ages may not accurately reflect aquifer residence time, due to mixtures of varying aged water.

  11. Water-level change, High Plains aquifer, 1980 to 1995

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents water-level change in the High Plains aquifer of the United States from 1980 to 1995, in feet. The High Plains aquifer underlies...

  12. Water-level change, High Plains aquifer, 2000 to 2005

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents water-level change in the High Plains aquifer of the United States from 2000 to 2005, in feet. The High Plains aquifer underlies...

  13. Water-level change, High Plains aquifer, 2005 to 2009

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents water-level change in the High Plains aquifer of the United States from 2005 to 2009, in feet. The High Plains aquifer underlies...

  14. Water-level change, High Plains aquifer, 1995 to 2000

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents water-level change in the High Plains aquifer of the United States from 1995 to 2000, in feet. The High Plains aquifer underlies...

  15. Snake River Plain Basin-fill aquifer system

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the extent of the Snake River Plain aquifer system, which includes both the basaltic and basin-fill aquifers. This dataset does not...

  16. Aquifers of Alluvial and Glacial Origin - Direct Download

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the extent of the alluvial and glacial aquifers north of the southern-most line of glaciation. Aquifers are shown in the States of Maine,...

  17. Aquifer parameter estimation from surface resistivity data.

    Science.gov (United States)

    Niwas, Sri; de Lima, Olivar A L

    2003-01-01

    This paper is devoted to the additional use, other than ground water exploration, of surface geoelectrical sounding data for aquifer hydraulic parameter estimation. In a mesoscopic framework, approximated analytical equations are developed separately for saline and for fresh water saturations. A few existing useful aquifer models, both for clean and shaley sandstones, are discussed in terms of their electrical and hydraulic effects, along with the linkage between the two. These equations are derived for insight and physical understanding of the phenomenon. In a macroscopic scale, a general aquifer model is proposed and analytical relations are derived for meaningful estimation, with a higher level of confidence, of hydraulic parameter from electrical parameters. The physical reasons for two different equations at the macroscopic level are explicitly explained to avoid confusion. Numerical examples from existing literature are reproduced to buttress our viewpoint. PMID:12533080

  18. Genetic algorithms and aquifer parameter identification

    Institute of Scientific and Technical Information of China (English)

    LI Jing-sheng(李竞生); YAO Lei-hua(姚磊华); LI Yang(李杨)

    2003-01-01

    In order to identify aquifer parameter,authors develops an improved combinatorial method called best chromosome clone plus younger generation chromosome prepotency genetic algorithm (BCC-YGCP-GA), based on a decimal system simple genetic algorithm (SGA). The paper takes unsteady state flows in a two-dimensional, inhomogeneous, confined aquifer for a ideal model, and utilizes SGA and BCC-YGCP-GA coupled to finite element method for identifying aquifer hydraulic conductivity K1,K2,K3 and storage S1,S2,S3, respectively. It is shown from the result that GSA does not reach convergence with 100 generations, whereas convergence rate of BCC-YGCD-GA is very fast. Objective function value calculated by BCC-YGCD-GA is 0.001 29 with 100 generations, and hydraulic conductivity and storage of three zones are almost equal to the "true" values of ideal model.

  19. Modeling contaminant plumes in fractured limestone aquifers

    DEFF Research Database (Denmark)

    Mosthaf, Klaus; Brauns, Bentje; Fjordbøge, Annika Sidelmann;

    Determining the fate and transport of contaminant plumes from contaminated sites in limestone aquifers is important because they are a major drinking water resource. This is challenging because they are often heavily fractured and contain chert layers and nodules, resulting in a complex transport...... the established approaches of the equivalent porous medium, discrete fracture and dual continuum models. However, these modeling concepts are not well tested for contaminant plume migration in limestone geologies. Our goal was to develop and evaluate approaches for modeling the transport of dissolved contaminant...... plumes in fractured limestone aquifers in 3D and to test methods for determining the required flow and transport parameters. The models were compared for a contaminated site in Denmark, where a plume of dissolved PCE has migrated through a fractured limestone aquifer. Numerical modeling was used...

  20. 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).

  1. Unconsolidated Aquifers in Tompkins County, New York

    Science.gov (United States)

    Miller, Todd S.

    2000-01-01

    Unconsolidated aquifers consisting of saturated sand and gravel are capable of supplying large quantities of good-quality water to wells in Tompkins County, but little published geohydrologic inform ation on such aquifers is available. In 1986, the U.S.Geological Survey (USGS) began collecting geohydrologic information and well data to construct an aquifer map showing the extent of unconsolidated aquifers in Tompkins county. Data sources included (1) water-well drillers. logs; (2) highway and other construction test-boring logs; (3) well data gathered by the Tompkins County Department of Health, (4) test-well logs from geohydrologic consultants that conducted projects for site-specific studies, and (5) well data that had been collected during past investigations by the USGS and entered into the National Water Information System (NWIS) database. In 1999, the USGS, in cooperation with the Tompkins County Department of Planning, compiled these data to construct this map. More than 600 well records were entered into the NWIS database in 1999 to supplement the 350 well records already in the database; this provided a total of 950 well records. The data were digitized and imported into a geographic information system (GIS) coverage so that well locations could be plotted on a map, and well data could be tabulated in a digital data base through ARC/INFO software. Data on the surficial geology were used with geohydrologic data from well records and previous studies to delineate the extent of aquifers on this map. This map depicts (1) the extent of unconsolidated aquifers in Tompkins County, and (2) locations of wells whose records were entered into the USGS NWIS database and made into a GIS digital coverage. The hydrologic information presented here is generalized and is not intended for detailed site evaluations. Precise locations of geohydrologic-unit boundaries, and a description of the hydrologic conditions within the units, would require additional detailed, site

  2. Aquifer thermal energy storage. International symposium: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-05-01

    Aquifers have been used to store large quantities of thermal energy to supply process cooling, space cooling, space heating, and ventilation air preheating, and can be used with or without heat pumps. Aquifers are used as energy sinks and sources when supply and demand for energy do not coincide. Aquifer thermal energy storage may be used on a short-term or long-term basis; as the sole source of energy or as a partial storage; at a temperature useful for direct application or needing upgrade. The sources of energy used for aquifer storage are ambient air, usually cold winter air; waste or by-product energy; and renewable energy such as solar. The present technical, financial and environmental status of ATES is promising. Numerous projects are operating and under development in several countries. These projects are listed and results from Canada and elsewhere are used to illustrate the present status of ATES. Technical obstacles have been addressed and have largely been overcome. Cold storage in aquifers can be seen as a standard design option in the near future as it presently is in some countries. The cost-effectiveness of aquifer thermal energy storage is based on the capital cost avoidance of conventional chilling equipment and energy savings. ATES is one of many developments in energy efficient building technology and its success depends on relating it to important building market and environmental trends. This paper attempts to provide guidance for the future implementation of ATES. Individual projects have been processed separately for entry onto the Department of Energy databases.

  3. Unconfined Aquifer Flow Theory - from Dupuit to present

    OpenAIRE

    Mishra, Phoolendra K.; Kuhlman, Kristopher L.

    2013-01-01

    Analytic and semi-analytic solution are often used by researchers and practicioners to estimate aquifer parameters from unconfined aquifer pumping tests. The non-linearities associated with unconfined (i.e., water table) aquifer tests makes their analysis more complex than confined tests. Although analytical solutions for unconfined flow began in the mid-1800s with Dupuit, Thiem was possibly the first to use them to estimate aquifer parameters from pumping tests in the early 1900s. In the 195...

  4. In situ microcosms in aquifer bioremediation studies.

    Science.gov (United States)

    Mandelbaum, R T; Shati, M R; Ronen, D

    1997-07-01

    The extent to which aquifer microbiota can be studied under laboratory or simulated conditions is limited by our inability to authentically duplicate natural conditions in the laboratory. Therefore, extrapolation of laboratory results to real aquifer situations is often criticized, unless validation of the data is performed in situ. Reliable data acquisition is critical for the estimation of chemical and biological reaction rates of biodegradation processes in groundwater and as input data for mathematical models. Typically, in situ geobiochemical studies relied on the injection of groundwater spiked with compounds or bacteria of interest into the aquifer, followed by monitoring the changes over time and space. In situ microcosms provide a more confined study site for measurements of microbial reactions, yet closer to natural conditions than laboratory microcosms. Two basic types of in situ aquifer microcosm have been described in recent years, and both originated from in situ instruments initially designed for geochemical measurements. Gillham et al. [Ground Water 28 (1990) 858-862] constructed an instrument that isolates a portion of an aquifer for in situ biochemical rate measurements. More recently Shati et al. [Environ. Sci. Technol. 30 (1996) 2646-2653] modified a multilayer sampler for studying the activity of inoculated bacteria in a contaminated aquifer Keeping in mind recent advances in environmental microbiology methodologies such as immunofluorescence direct counts, oligonucleotide and PCR probes, fatty acid methyl esther analysis for the detection and characterization of bacterial communities, measurement of mRNA and expression of proteins, it is evident that much new information can now be gained from in situ work. Using in situ microcosms to study bioremediation efficiencies, the fate of introduced microorganisms and general geobiochemical aquifer processes can shed more realistic light on the microbial underworld. The aim of this paper is to

  5. Predicted nitrate and arsenic concentrations in basin-fill aquifers of the Southwest Principal Aquifers study area

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This product "Predicted nitrate and arsenic concentrations in basin-fill aquifers of the Southwest Principal Aquifers study area" is a 1:250,000-scale vector...

  6. EPA Region 6 Sole Source Aquifers in Louisiana, Geographic NAD83, EPA (1996) [sole_source_aquifers_LA_EPA_1996

    Data.gov (United States)

    Louisiana Geographic Information Center — Polygon layer of EPA Region 6 sole source aquifers in Louisiana. The sole source aquifers represented are Chicot and Southern Hills in Louisiana/Mississippi.

  7. Digital data sets that describe aquifer characteristics of the Vamoosa-Ada aquifer in east-central Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digitized water-level elevation contours for the Vamoosa-Ada aquifer in east-central Oklahoma. The Vamoosa-Ada aquifer is an important...

  8. Digital data sets that describe aquifer characteristics of the Vamoosa-Ada aquifer in east-central Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digitized polygons of constant hydraulic conductivity values for the Vamoosa-Ada aquifer in east-central Oklahoma. The Vamoosa-Ada aquifer...

  9. Digital data sets that describe aquifer characteristics of the Vamoosa-Ada aquifer in east-central Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digitized polygons of constant recharge values for the Vamoosa-Ada aquifer, in east-central Oklahoma. The Vamoosa-Ada aquifer is an...

  10. Examples of transient sounding from groundwater exploration in sedimentary aquifers

    Science.gov (United States)

    Fitterman, D.V.

    1987-01-01

    Examples of the use of transient electromagnetic soundings for three groundwater exploration problems in sedimentary aquifers are given. The examples include: 1) estimating depths to water table and bedrock in an alluvium-filled basin, 2) mapping a confined freshwater aquifer in bedrock sediments, and 3) locating a freshwater/saltwater interface in a glacial-outwash aquifer. -from Author

  11. Review: The Yucatán Peninsula karst aquifer, Mexico

    DEFF Research Database (Denmark)

    Bauer-Gottwein, Peter; Gondwe, Bibi Ruth Neuman; Charvet, Guillaume;

    2011-01-01

    The Yucatán Peninsula karst aquifer is one of the most extensive and spectacular karst aquifer systems on the planet. This transboundary aquifer system extends over an area of approximately 165,000 km2 in México, Guatemala and Belize. The Triassic to Holocene Yucatán limestone platform is located...

  12. Groundwater modeling of the Calera Aquifer region in Central Mexico

    Science.gov (United States)

    The Calera Aquifer is the main source of water for irrigated agriculture, industrial, and drinking water purposes in the Calera Aquifer Region (CAR) in the state of Zacatecas, Mexico. Irrigated agriculture accounts for 80% of the total groundwater extracted from the Calera Aquifer. In recent years, ...

  13. Aquifer geochemistry at potential aquifer storage and recovery sites in coastal plain aquifers in the New York city area, USA

    Science.gov (United States)

    Brown, C.J.; Misut, P.E.

    2010-01-01

    The effects of injecting oxic water from the New York city (NYC) drinking-water supply and distribution system into a nearby anoxic coastal plain aquifer for later recovery during periods of water shortage (aquifer storage and recovery, or ASR) were simulated by a 3-dimensional, reactive-solute transport model. The Cretaceous aquifer system in the NYC area of New York and New Jersey, USA contains pyrite, goethite, locally occurring siderite, lignite, and locally varying amounts of dissolved Fe and salinity. Sediment from cores drilled on Staten Island and western Long Island had high extractable concentrations of Fe, Mn, and acid volatile sulfides (AVS) plus chromium-reducible sulfides (CRS) and low concentrations of As, Pb, Cd, Cr, Cu and U. Similarly, water samples from the Lloyd aquifer (Cretaceous) in western Long Island generally contained high concentrations of Fe and Mn and low concentrations of other trace elements such as As, Pb, Cd, Cr, Cu and U, all of which were below US Environmental Protection Agency (USEPA) and NY maximum contaminant levels (MCLs). In such aquifer settings, ASR operations can be complicated by the oxidative dissolution of pyrite, low pH, and high concentrations of dissolved Fe in extracted water.The simulated injection of buffered, oxic city water into a hypothetical ASR well increased the hydraulic head at the well, displaced the ambient groundwater, and formed a spheroid of injected water with lower concentrations of Fe, Mn and major ions in water surrounding the ASR well, than in ambient water. Both the dissolved O2 concentrations and the pH of water near the well generally increased in magnitude during the simulated 5-a injection phase. The resultant oxidation of Fe2+ and attendant precipitation of goethite during injection provided a substrate for sorption of dissolved Fe during the 8-a extraction phase. The baseline scenario with a low (0.001M) concentration of pyrite in aquifer sediments, indicated that nearly 190% more water

  14. Digital data sets that describe aquifer characteristics of the Enid isolated terrace aquifer in northwestern Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of a digitized polygon of a constant recharge value for the Enid isolated terrace aquifer in northwestern Oklahoma. The Enid isolated terrace...

  15. Digital data sets that describe aquifer characteristics of the Enid isolated terrace aquifer in northwestern Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digitized polygons of constant hydraulic conductivity values for the Enid isolated terrace aquifer in northwestern Oklahoma. The Enid...

  16. Digital data sets that describe aquifer characteristics of the Rush Springs aquifer in western Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digitized polygons of constant recharge values for the Rush Springs aquifer in western Oklahoma. This area encompasses all or part of...

  17. Digital data sets that describe aquifer characteristics of the Central Oklahoma aquifer in central Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digitized water-level elevation contours for the Central Oklahoma aquifer in central Oklahoma. This area encompasses all or part of...

  18. Denitrification in a deep basalt aquifer: implications for aquifer storage and recovery.

    Science.gov (United States)

    Nelson, Dennis; Melady, Jason

    2014-01-01

    Aquifer storage and recovery (ASR) can provide a means of storing water for irrigation in agricultural areas where water availability is limited. A concern, however, is that the injected water may lead to a degradation of groundwater quality. In many agricultural areas, nitrate is a limiting factor. In the Umatilla Basin in north central Oregon, shallow alluvial groundwater with elevated nitrate-nitrogen of 9 mg/L is injected into the Columbia River Basalt Group (CRBG), a transmissive confined aquifer(s) with low natural recharge rates. Once recovery of the injected water begins, however, NO3 -N in the recovered water decreases quickly to  +50, and correlate inversely with NO3 -N concentrations. This variation occurs in basalt aquifer, averaging 3.0 mg/L. Similar to nitrate concentrations, TOC drops in the recovered water, consistent with this component contributing to the denitrification of nitrate during storage.

  19. State Aquifer Recharge Atlas Plates, Geographic NAD83, LDEQ (1999) [aquifer_recharge_potential_LDEQ_1988

    Data.gov (United States)

    Louisiana Geographic Information Center — This is a polygon dataset depicting the boundaries of aquifer systems in the state of Louisiana and adjacent areas of Texas, Arkansas and a portion of Mississippi....

  20. Digital data sets that describe aquifer characteristics of the Rush Springs aquifer in western Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digitized polygons of constant hydraulic conductivity values for the Rush Springs aquifer in western Oklahoma. This area encompasses all...

  1. Digital data sets that describe aquifer characteristics of the Antlers aquifer in southeastern Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digitized polygons of a constant hydraulic conductivity value for the Antlers aquifer in southeastern Oklahoma. The Early Cretaceous-age...

  2. Digital data sets that describe aquifer characteristics of the Antlers aquifer in southeastern Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digitized water-level elevation contours for the Antlers aquifer in southeastern Oklahoma. The Early Cretaceous-age Antlers Sandstone is...

  3. Digital data sets that describe aquifer characteristics of the High Plains aquifer in western Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital polygons of constant hydraulic conductivity values for the High Plains aquifer in Oklahoma. This area encompasses the panhandle...

  4. Digital data sets that describe aquifer characteristics of the Central Oklahoma aquifer in central Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digitized polygons of a constant recharge value for the Central Oklahoma aquifer in central Oklahoma. This area encompasses all or part of...

  5. Digital data sets that describe aquifer characteristics of the High Plains aquifer in western Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digitized water-level elevation contours for the High Plains aquifer in western Oklahoma. This area encompasses the panhandle counties of...

  6. Digital data sets that describe aquifer characteristics of the High Plains aquifer in western Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital polygons of constant recharge rates for the High Plains aquifer in Oklahoma. This area encompasses the panhandle counties of...

  7. Digital data sets that describe aquifer characteristics of the Central Oklahoma aquifer in central Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digitized polygons of a constant hydraulic conductivity value for the Central Oklahoma aquifer in central Oklahoma. This area encompasses...

  8. Digital data sets that describe aquifer characteristics of the Rush Springs aquifer in western Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digitized water-level elevation contours for the Rush Springs aquifer in western Oklahoma. This area encompasses all or part of Blaine,...

  9. Digital data sets that describe aquifer characteristics of the Antlers aquifer in southeastern Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digitized polygons of constant recharge values for the Antlers aquifer in southeastern Oklahoma. The Early Cretaceous-age Antlers...

  10. Aquifer Boundary of the Wood River Valley Aquifer System, South-Central Idaho

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset contains the boundary of the Wood River Valley aquifer system as modified and expanded from that defined by Skinner and others (2007): It has been...

  11. Hydrogeochemical Analysis of an Overexploited Aquifer In Bangladesh Toward Managed Aquifer Recharge Project Implementation

    Science.gov (United States)

    Rahman, M. A.; Wiegand, B. A.; Pervin, M.; Sauter, M.

    2012-12-01

    In most parts of the upper Dupitila aquifer (Dhaka City, Bangladesh) the average groundwater depletion reaches 2-3 m/year due to increasing water demands of the growing population. To counteract overexploitation of the aquifer, a more sustainable water management is required. The analysis of the local water resources system suggests that Managed Aquifer Recharge (MAR) would help to restore groundwater resources to strengthen water supply of Dhaka City, e.g., by using collected urban monsoon runoff and excess surface water from rivers. To assess possible effects of surface water or rainwater injection on groundwater quality, a comprehensive hydrogeochemical survey of the Dupitila aquifer is required. This paper presents hydrogeochemical data to document the current status of groundwater quality and to evaluate potential groundwater pollution by mobilization of hazardous chemicals as a result of changes in the hydrochemical equilibria. We performed a comprehensive review of available secondary data sources and will present new results from hydrochemical and Sr isotope investigations of water samples that were conducted within this study. Currently, groundwater quality in the upper Dupitila aquifer is characterized by variations in the electrical conductivity in the range of 200 to 1100 μS/cm, which may indicate some anthropogenic contamination by leakage from waste disposal including the sewage network and from surface water infiltration into the groundwater aquifer. Dissolved oxygen concentrations range from 1.0 to 4.9 mg/L (average 2.5 mg/L) in the upper Dupitila aquifer, while the lower Dupilita aquifer shows dissolved oxygen concentrations in the range 0 to 0.7 mg/L. Concentrations of major ions show some variation primarily due to a sedimentologically/mineralogically heterogeneous aquifer composition (sand, gravel, clay horizons), but may also be affected by anthropogenic processes. The groundwater composition is predominated by Ca-Mg-HCO3 and saturation values

  12. Steady state phreatic surfaces in sloping aquifers

    Science.gov (United States)

    Loáiciga, Hugo A.

    2005-08-01

    Steady state groundwater flow driven by constant recharge in an unconfined aquifer overlying sloping bedrock is shown to be represented, using the Dupuit approximation, by an ordinary differential equation of the Abel type y(x) . y'(x) + a . y(x) + x = 0, whose analytical solution is derived in this work. This article first investigates the case of zero saturated thickness at the upstream boundary, a flow system reminiscent of perched groundwater created by percolation of precipitation or irrigation in a sloping aquifer fully draining at its downstream boundary. A variant of this flow system occurs when the phreatic surface mounds and produces groundwater discharge toward the upstream boundary. This variant is a generalization of the classical groundwater flow problem involving two lakes connected by an aquifer, the latter being on sloping terrain in this instance. Analytical solutions for the phreatic surface's steady state geometry are derived for the case of monotonically declining hydraulic head as well as for the case of a mounded phreatic surface. These solutions are of practical interest in drainage studies, slope stability, and runoff formation investigations. It is shown that the flow factor a = -$\\sqrt{{\\rm K}/{\\rm N} tan β (where K, N, and tan β are the hydraulic conductivity, vertical recharge, and aquifer slope, respectively) has a commanding role on the phreatic surface's solutions. Two computational examples illustrate the implementation of this article's results.

  13. Biogeochemical aspects of aquifer thermal energy storage.

    NARCIS (Netherlands)

    Brons, H.J.

    1992-01-01

    During the process of aquifer thermal energy storage the in situ temperature of the groundwater- sediment system may fluctuate significantly. As a result the groundwater characteristics can be considerably affected by a variety of chemical, biogeochemical and microbiological reactions. The inter

  14. PREDICTING CONTAMINANT MIGRATION IN KARST AQUIFERS

    Science.gov (United States)

    Time-of-travel transport estimation is employed to predict contaminant migration in karst aquifers. stimation of time-of-travel transport is conditioned on the set of hydraulic-flow and geometric parameters that describe different transport processes that occur within karst condu...

  15. Transport of nonlinearly biodegradable contaminants in aquifers

    NARCIS (Netherlands)

    Keijzer, H.

    2001-01-01

    This thesis deals with the transport behavior of nonlinearly biodegradable contaminants in aquifers. Such transport occurs during in situ bioremediation which is based on the injection of an electron acceptor or electron donor. The main interests in this thesis are the mutual influences of underlyin

  16. Groundwater sustainability assessment in coastal aquifers

    Science.gov (United States)

    Lathashri, U. A.; Mahesha, A.

    2016-08-01

    The present work investigates the response of shallow, coastal unconfined aquifers to anticipated overdraft conditions and climate change effect using numerical simulation. The groundwater flow model MODFLOW and variable density groundwater model SEAWAT are used for this investigation. The transmissivity and specific yield estimated from the existing database range from 10 to 810 m 2/day and 0.08% to 10.92% respectively. After successful calibration with Nash-Sutcliffe efficiency greater than 0.80, the values of horizontal hydraulic conductivity and specific yield of the unconfined aquifer were set in the range 1.85-61.90 m/day and 0.006-0.24 respectively. After validating the model, it is applied for forecasting the aquifer's response to anticipated future scenarios of groundwater draft, recharge rate and sea level rise. The findings of the study illustrate that saltwater intrusion is intensified in the area adjoining the tidal rivers, rather than that due to the sea alone. Of all the scenarios simulated, the immense negative impact on groundwater quality emerges due to overdraft conditions and reduced recharge with the areal extent of seawater intrusion exceeding about 67% (TDS >1 kg/m 3). The study also arrives at the conclusion that, regional sea level rise of 1 mm/year has no impact on the groundwater dynamics of the aquifer.

  17. 40 CFR 147.102 - Aquifer exemptions.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Aquifer exemptions. 147.102 Section 147.102 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS...) Granite Point. (ii) McArthur River Field. (iii) Middle Ground Shoal Field. (iv) Trading Bay Field. (3)...

  18. The Coffee Sand and Ripley aquifers in Mississippi

    Science.gov (United States)

    Boswell, E.H.

    1978-01-01

    The Coffee Sand and Ripley aquifers, of Cretaceous age, are in the Selma Group in northern Mississippi. The aquifers contain freshwater in an area of about 4,400 square miles in northern Mississippi. Water produced from the aquifers by public water systems and numerous industries in 1975 averaged about 4 Mgal/d. Regional water-level declines have been very small and the aquifers have a moderate potential for future development. The aquifers are used in some areas where there are no other significant sources of ground water. The most common problems in developing water supplies are low yields to wells and hard water. (Kosco-USGS)

  19. 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.

  20. Digital Map Of Base of Aquifer for High Plains Aquifer in parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital base of aquifer elevation contours for the High Plains aquifer in the central United States. The High Plains aquifer extends from...

  1. Digital map of aquifer boundary for the High Plains aquifer in parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set consists of aquifer boundaries for the High Plains aquifer in the central United States. The High Plains aquifer extends from south of 32...

  2. Source, variability, and transformation of nitrate in a regional karst aquifer: Edwards aquifer, central Texas.

    Science.gov (United States)

    Musgrove, M; Opsahl, S P; Mahler, B J; Herrington, C; Sample, T L; Banta, J R

    2016-10-15

    Many karst regions are undergoing rapid population growth and expansion of urban land accompanied by increases in wastewater generation and changing patterns of nitrate (NO3(-)) loading to surface and groundwater. We investigate variability and sources of NO3(-) in a regional karst aquifer system, the Edwards aquifer of central Texas. Samples from streams recharging the aquifer, groundwater wells, and springs were collected during 2008-12 from the Barton Springs and San Antonio segments of the Edwards aquifer and analyzed for nitrogen (N) species concentrations and NO3(-) stable isotopes (δ(15)N and δ(18)O). These data were augmented by historical data collected from 1937 to 2007. NO3(-) concentrations and discharge data indicate that short-term variability (days to months) in groundwater NO3(-) concentrations in the Barton Springs segment is controlled by occurrence of individual storms and multi-annual wet-dry cycles, whereas the lack of short-term variability in groundwater in the San Antonio segment indicates the dominance of transport along regional flow paths. In both segments, longer-term increases (years to decades) in NO3(-) concentrations cannot be attributed to hydrologic conditions; rather, isotopic ratios and land-use change indicate that septic systems and land application of treated wastewater might be the source of increased loading of NO3(-). These results highlight the vulnerability of karst aquifers to NO3(-) contamination from urban wastewater. An analysis of N-species loading in recharge and discharge for the Barton Springs segment during 2008-10 indicates an overall mass balance in total N, but recharge contains higher concentrations of organic N and lower concentrations of NO3(-) than does discharge, consistent with nitrification of organic N within the aquifer and consumption of dissolved oxygen. This study demonstrates that subaqueous nitrification of organic N in the aquifer, as opposed to in soils, might be a previously unrecognized

  3. Selecting Aquifer Wells for Planned Gyroscopic Logging

    Energy Technology Data Exchange (ETDEWEB)

    Rohe, Michael James; Studley, Gregory Wayne

    2002-04-01

    Understanding the configuration of the eastern Snake River Plain aquifer's water table is made difficult, in part, due to borehole deviation in aquifer wells. A borehole has deviation if it is not vertical or straight. Deviation impairs the analysis of water table elevation measurements because it results in measurements that are greater than the true distance from the top of the well to the water table. Conceptual models of the water table configuration are important to environmental management decision-making at the INEEL; these models are based on measurements of depth to the water table taken from aquifer wells at or near the INEEL. When accurate data on the amount of deviation in any given borehole is acquired, then measurements of depth-to-water can be adjusted to reflect the true depth so more accurate conceptual models can be developed. Collection of additional borehole deviation data with gyroscopic logging is planned for selected wells to further our confidence in the quality of water level measurements. Selection of wells for the planned logging is based on qualitative and quantitative screening criteria. An existing data set from magnetic deviation logs was useful in establishing these criteria however, are considered less accurate than gyroscopic deviation logs under certain conditions. Population distributions for 128 aquifer wells with magnetic deviation data were used to establish three quantitative screening thresholds. Qualitative criteria consisted of administrative controls, accessibility issues, and drilling methods. Qualitative criteria eliminated all but 116 of the 337 aquifer wells, in the vicinity of the INEEL, that were initially examined in this screening effort. Of these, 72 have associated magnetic deviation data; 44 do not. Twenty-five (25) of the 72 wells with magnetic deviation data have deviation greater than one of the three quantitative screening thresholds. These 25 are recommended for the planned gyroscopic borehole deviation

  4. The High Plains Aquifer, USA: Groundwater development and sustainability

    Science.gov (United States)

    Dennehy, K.F.; Litke, D.W.; McMahon, P.B.

    2002-01-01

    The High Plains Aquifer, located in the United States, is one of the largest freshwater aquifers in the world and is threatened by continued decline in water levels and deteriorating water quality. Understanding the physical and cultural features of this area is essential to assessing the factors that affect this groundwater resource. About 27% of the irrigated land in the United States overlies this aquifer, which yields about 30% of the nation's groundwater used for irrigation of crops including wheat, corn, sorghum, cotton and alfalfa. In addition, the aquifer provides drinking water to 82% of the 2.3 million people who live within the aquifer boundary. The High Plains Aquifer has been significantly impacted by human activities. Groundwater withdrawals from the aquifer exceed recharge in many areas, resulting in substantial declines in groundwater level. Residents once believed that the aquifer was an unlimited resource of high-quality water, but they now face the prospect that much of the water may be gone in the near future. Also, agricultural chemicals are affecting the groundwater quality. Increasing concentrations of nitrate and salinity can first impair the use of the water for public supply and then affect its suitability for irrigation. A variety of technical and institutional measures are currently being planned and implemented across the aquifer area in an attempt to sustain this groundwater resource for future generations. However, because groundwater withdrawals remain high and water quality impairments are becoming more commonplace, the sustainability of the High Plains Aquifer is uncertain.

  5. Atrazine removal in Danish anaerobic aquifers

    DEFF Research Database (Denmark)

    Pedersen, Philip Grinder; Arildskov, N.P.; Albrechtsen, Hans-Jørgen

    2002-01-01

    The pesticide atrazine (6-chloro-N-2-ethyl-N-4-isopropyl-1,3,5-triazine -2,4-diamine) was removed from the water phase in anaerobic laboratory batch incubations with sediment and groundwater from a number of Danish anaerobic aquifers, but not in incubations from aerobic aquifers. The removal...... process was abiotic since atrazine was also removed from microbially inhibited autoclaved and chloroform amended controls, although in controls amended with mercury, atrazine removal was slowed down. (ring-U-C-14)- atrazine amended samples showed no mineralization to (CO2)-C-14 or transformation...... to soluble degradation products, indicating that a slow sorption process was responsible for the atrazine removal. Approximately 20% of the applied C-14-atrazine was present in a non-extractable residual sediment bound fraction, indicating the slow sorption process to be in part irreversible...

  6. Opportunities to enhance management of karstic aquifers

    Science.gov (United States)

    Parizek, Richard R.

    2007-01-01

    Methods exist to obtain “new sources of water.” Examples include: (1) capturing and enhancing stormwater recharge and retention within diffuse-flow portions of karst and other aquifers; (2) recycling and reuse of waste water; (3) reducing evapotranspiration and rejected recharge; and (4) ameliorating atmospheric acid deposition through use of alkaline groundwater. These little used management methods have immense potential to sustain future water demands. Full utilization of “new” and traditional water resources requires an understanding of the hydrogeologic framework of karstic aquifers. Reliable conceptual, numerical flow and transport models are needed to help evaluate, select, and design viable water management options. Three such simulation examples are provided together with a discussion of Penn State’s Wastewater reuse project where recharge approaches 3.785 × 109l/year

  7. Biogeochemical aspects of aquifer thermal energy storage.

    OpenAIRE

    Brons, H.J.

    1992-01-01

    During the process of aquifer thermal energy storage the in situ temperature of the groundwater- sediment system may fluctuate significantly. As a result the groundwater characteristics can be considerably affected by a variety of chemical, biogeochemical and microbiological reactions. The interplay of these reactions may have a negative influence on the operational performance of ATES-systems. The objective of this thesis was to investigate bacterial clogging processes and the biogeochemical...

  8. Nitrate in aquifers beneath agricultural systems

    Science.gov (United States)

    Burkart, M.R.; Stoner, J.D.; ,

    2007-01-01

    Research from several regions of the world provides spatially anecdotal evidence to hypothesize which hydrologic and agricultural factors contribute to groundwater vulnerability to nitrate contamination. Analysis of nationally consistent measurements from the U.S. Geological Survey's NAWQA program confirms these hypotheses for a substantial range of agricultural systems. Shallow unconfined aquifers are most susceptible to nitrate contamination associated with agricultural systems. Alluvial and other unconsolidated aquifers are the most vulnerable and also shallow carbonate aquifers that provide a substantial but smaller contamination risk. Where any of these aquifers are overlain by permeable soils the risk of contamination is larger. Irrigated systems can compound this vulnerability by increasing leaching facilitated by additional recharge and additional nutrient applications. The system of corn, soybean, and hogs produced significantly larger concentrations of groundwater nitrate than all other agricultural systems because this system imports the largest amount of N-fertilizer per unit production area. Mean nitrate under dairy, poultry, horticulture, and cattle and grains systems were similar. If trends in the relation between increased fertilizer use and groundwater nitrate in the United States are repeated in other regions of the world, Asia may experience increasing problems because of recent increases in fertilizer use. Groundwater monitoring in Western and Eastern Europe as well as Russia over the next decade may provide data to determine if the trend in increased nitrate contamination can be reversed. If the concentrated livestock trend in the United States is global, it may be accompanied by increasing nitrogen contamination in groundwater. Concentrated livestock provide both point sources in the confinement area and intense non-point sources as fields close to facilities are used for manure disposal. Regions where irrigated cropland is expanding, such as

  9. Biodegradation of cresol isomers in anoxic aquifers.

    OpenAIRE

    Smolenski, W J; Suflita, J M

    1987-01-01

    The biodegradation of o-, m-, and p-cresol was examined in material obtained from a shallow anaerobic alluvial sand aquifer. The cresol isomers were preferentially metabolized, with p-cresol being the most easily degraded. m-Cresol was more persistent than the para-isomer, and o-cresol persisted for over 90 days. Biodegradation of cresol isomers was favored under sulfate-reducing conditions (SRC) compared with that under methanogenic conditions (MC). Slurries that were acclimated to p-cresol ...

  10. 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...

  11. Groundwater sustainability assessment in coastal aquifers

    Indian Academy of Sciences (India)

    U A Lathashri; A Mahesha

    2016-08-01

    The present work investigates the response of shallow, coastal unconfined aquifers to anticipated overdraft conditions and climate change effect using numerical simulation. The groundwater flow model MODFLOW and variable density groundwater model SEAWAT are used for this investigation. The transmissivity and specific yield estimated from the existing database range from 10 to 810 m^2/day and 0.08% to 10.92% respectively. After successful calibration with Nash–Sutcliffe efficiency greater than 0.80, the values of horizontal hydraulic conductivity and specific yield of the unconfined aquifer were set in the range 1.85–61.90 m/day and 0.006–0.24 respectively. After validating the model, it is applied for forecasting the aquifer’s response to anticipated future scenarios of groundwater draft, recharge rate and sea level rise. The findings of the study illustrate that saltwater intrusion is intensified in the area adjoining the tidal rivers, rather than that due to the sea alone. Of all the scenarios simulated, the immense negative impact on groundwater quality emerges due to overdraft conditions and reduced recharge with the areal extent of seawater intrusion exceeding about 67% (TDS>1 kg/m^3). The study also arrivesat the conclusion that, regional sea level rise of 1 mm/year has no impact on the groundwater dynamics of the aquifer.

  12. Unconfined Aquifer Flow Theory - from Dupuit to present

    CERN Document Server

    Mishra, Phoolendra K

    2013-01-01

    Analytic and semi-analytic solution are often used by researchers and practicioners to estimate aquifer parameters from unconfined aquifer pumping tests. The non-linearities associated with unconfined (i.e., water table) aquifer tests makes their analysis more complex than confined tests. Although analytical solutions for unconfined flow began in the mid-1800s with Dupuit, Thiem was possibly the first to use them to estimate aquifer parameters from pumping tests in the early 1900s. In the 1950s, Boulton developed the first transient well test solution specialized to unconfined flow. By the 1970s Neuman had developed solutions considering both primary transient storage mechanisms (confined storage and delayed yield) without non-physical fitting parameters. In the last decade, research into developing unconfined aquifer test solutions has mostly focused on explicitly coupling the aquifer with the linearized vadose zone. Despite the many advanced solution methods available, there still exists a need for realism ...

  13. Recharge and Aquifer Response: Manukan Island’s Aquifer, Sabah, Malaysia

    Directory of Open Access Journals (Sweden)

    Sarva Mangala Praveena

    2010-01-01

    Full Text Available Manukan Island is a small island located in North-West of Sabah, Malaysia was used as a case study area for numerical modeling of an aquifer response to recharge and pumping rates. The results in this study present the variations of recharge into the aquifer under the prediction simulations. The recharge rate increases the water level as indicated by hydraulic heads. This shows that it can alter groundwater of Manukan Island which has been suffering from an overexploration in its unconfined the aquifer. The increase in recharge rate (from 600 mm/year to 750 mm/year increases the water level indicated by hydraulic heads. A reduction in pumping rate (from 0.072 m3/day to 0.058 m3/day not only increases the amount of water levels in aquifer but also reduces the supply hence a deficit in supply. The increase in hydraulic heads depends on the percentage reduction of pumping and recharges rates. The well water has 1978.3 mg/L chloride with current pumping (0.072 m3/day and recharge rates (600 mm/year. However, with an increased of recharge rate and current pumping rate it has decreased about 1.13%. In addition, reduction in pumping rate made the chloride concentration decreased about 2.8%. In general, a reduction in pumping with an increase in recharge rate leads to a decreased in chloride concentrations within the vicinity of cone of depression. Next, to further develop the numerical model, the model should focus on climate change variables such as consequences of climate change are increase in air temperature, increase in sea surface temperature, and more extreme weather conditions. These parameters are considered critical parameters for climate change impact modeling in aquifers. The behavior of the aquifer and its sustainable pumping rate can be done by applying a computer modeling component.

  14. Thermal tracer tests for characterizing a shallow alluvial aquifer

    OpenAIRE

    Wildemeersch, Samuel; Klepikova, Maria; Jamin, Pierre; Orban, Philippe; Hermans, Thomas; Brouyère, Serge; Dassargues, Alain

    2014-01-01

    Using heat as an active tracer in different types of aquifers is a topic of increasing interest [e.g. Vandenbohede et al.; 2008, Wagner et al., 2013; Read et al., 2013]. In this study, we investigate the potential interest of coupling heat and solute tracer tests for characterization of a shallow alluvial aquifer. A thermal tracer test was conducted in the alluvial aquifer of the Meuse River, Belgium. The tracing experiment consisted in simultaneously injecting heated water and a dye tracer i...

  15. Microbiological risks of recycling urban stormwater via aquifers.

    Science.gov (United States)

    Page, D; Gonzalez, D; Dillon, P

    2012-01-01

    With the release of the Australian Guidelines for Water Recycling: Managed Aquifer Recharge (MAR), aquifers are now being included as a treatment barrier when assessing risk of recycled water systems. A MAR research site recharging urban stormwater in a confined aquifer was used in conjunction with a Quantitative Microbial Risk Assessment to assess the microbial pathogen risk in the recovered water for different end uses. The assessment involved undertaking a detailed assessment of the treatment steps and exposure controls, including the aquifer, to achieve the microbial health-based targets.

  16. RECOVERY OF FRESHWATER STORED IN SALINE AQUIFERS IN PENINSULAR FLORIDA.

    Science.gov (United States)

    Merritt, Michael L.

    1986-01-01

    Subsurface freshwater storage has been operationally tested at seven sites in central and south Florida. Injection was into a high chloride water aquifer at six sites, and into a high sulfate water aquifer at the seventh. Recovery efficiency has ranged from 0 to 75 percent in high chloride water aquifers, and has exceeded 100 percent in the high sulfate water aquifer. Computer modeling techniques were used to examine the geohydrologic, design, and management factors governing the recovery efficiency of subsurface freshwater storage. The modeling approach permitted many combinations of geohydrologic and operational conditions to be studied at relatively low cost.

  17. Hydrogeology and Aquifer Storage and Recovery Performance in the Upper Floridan Aquifer, Southern Florida

    Science.gov (United States)

    Reese, Ronald S.; Alvarez-Zarikian, Carlos A.

    2007-01-01

    Well construction, hydraulic well test, ambient water-quality, and cycle test data were inventoried and compiled for 30 aquifer storage and recovery facilities constructed in the Floridan aquifer system in southern Florida. Most of the facilities are operated by local municipalities or counties in coastal areas, but five sites are currently being evaluated as part of the Comprehensive Everglades Restoration Plan. The relative performance of all sites with adequate cycle test data was determined, and compared with four hydrogeologic and design factors that may affect recovery efficiency. Testing or operational cycles include recharge, storage, and recovery periods that each last days or months. Cycle test data calculations were made including the potable water (chloride concentration of less than 250 milligrams per liter) recovery efficiency per cycle, total recovery efficiency per cycle, and cumulative potable water recovery efficiencies for all of the cycles at each site. The potable water recovery efficiency is the percentage of the total amount of potable water recharged for each cycle that is recovered; potable water recovery efficiency calculations (per cycle and cumulative) were the primary measures used to evaluate site performance in this study. Total recovery efficiency, which is the percent recovery at the end of each cycle, however, can be substantially higher and is the performance measure normally used in the operation of water-treatment plants. The Upper Floridan aquifer of the Floridan aquifer system currently is being used, or planned for use, at 29 of the aquifer storage and recovery sites. The Upper Floridan aquifer is continuous throughout southern Florida, and its overlying confinement is generally good; however, the aquifer contains brackish to saline ground water that can greatly affect freshwater storage and recovery due to dispersive mixing within the aquifer. The hydrogeology of the Upper Floridan varies in southern Florida; confinement

  18. Straddle-packer aquifer test analyses of the Snake River Plain aquifer at the Idaho National Engineering Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, G.S.; Frederick, D.B.

    1997-01-01

    The State of Idaho INEL Oversight Program, with the University of Idaho, Idaho State University, Boise State University, and the Idaho Geologic Survey, used a straddle-packer system to investigate vertical variations in characteristics of the Snake River Plain aquifer at the Idaho National Engineering Laboratory in southeast Idaho. Sixteen single-well aquifer tests were conducted on.isolated intervals in three observation wells. Each of these wells has approximately 200 feet of open borehole below the water table, penetrating the E through G and I basalt flow groups and interbedded sediments of the Snake River Plain aquifer. The success of the aquifer tests was limited by the inability to induce measurable drawdown in several zones. Time-drawdown data from aquifer tests were matched to type curves for 8 of the 16 zones tested. A single aquifer test at the water table exhibited greater curvature than those at depth. The increased degree of curvature suggests an unconfined response and resulted in an estimate of specific yield of 0.03. Aquifer tests below the water table generally yielded time-drawdown graphs with a rapid initial response followed by constant drawdown throughout the duration of the tests; up to several hours in length. The rapid initial response implies that the aquifer responds as a confined system during brief pumping periods. The nearly constant drawdown suggests a secondary source of water, probably vertical flow from overlying and underlying aquifer layers. Three analytical models were applied for comparison to the conceptual model and to provide estimates of aquifer properties. This, Hantush-Jacob leaky aquifer, and the Moench double-porosity fractured rock models were fit to time-drawdown data. The leaky aquifer type curves of Hantush and Jacob generally provided the best match to observed drawdown. A specific capacity regression equation was also used to estimate hydraulic conductivity.

  19. Karst Aquifer Recharge: Comments on Somaratne, N. Characteristics of Point Recharge in Karst Aquifers. Water 2014, 6, 2782–2807

    OpenAIRE

    Adrian D. Werner

    2014-01-01

    The article “Characteristics of Point Recharge in Karst Aquifers, Water 6: 2782–2807” by N. Somaratne evaluates various recharge estimation techniques applied to four limestone aquifers in South Australia. Somaratne [1] concludes that methods based on watertable fluctuations, groundwater modelling and water budgets are independent of recharge processes, and are therefore superior to the chloride mass balance (CMB) approach for karst aquifers. The current comment offers alternative interpreta...

  20. Hydrogeology of the Cambrian-Ordovician aquifer system in the northern Midwest: B in Regional aquifer-system analysis

    Science.gov (United States)

    Young, H.L.; Siegel, D.I.

    1992-01-01

    The Cambrian-Ordovician aquifer system contains the most extensive and continuous aquifers in the northern Midwest of the United States. It is the source of water for many municipalities, industries, and rural water users. Since the beginning of ground-water development from the aquifer system in the late 1800's, hydraulic heads have declined hundreds of feet in the heavily pumped Chicago-Milwaukee area and somewhat less in other metropolitan areas. The U.S. Geological Survey has completed a regional assessment of this aquifer system within a 161,000-square-mile area encompassing northern Illinois, northwestern Indiana, Iowa, southeastern Minnesota, northern Missouri, and Wisconsin.

  1. Effects of clay dispersion on aquifer storage and recovery in coastal aquifers

    Science.gov (United States)

    Konikow, L.F.; August, L.L.; Voss, C.I.

    2001-01-01

    Cyclic injection, storage, and withdrawal of freshwater in brackish aquifers is a form of aquifer storage and recovery (ASR) that can beneficially supplement water supplies in coastal areas. A 1970s field experiment in Norfolk, Virginia, showed that clay dispersion in the unconsolidated sedimentary aquifer occurred because of cation exchange on clay minerals as freshwater displaced brackish formation water. Migration of interstitial clay particles clogged pores, reduced permeability, and decreased recovery efficiency, but a calcium preflush was found to reduce clay dispersion and lead to a higher recovery efficiency. Column experiments were performed in this study to quantify the relations between permeability changes and clay mineralogy, clay content, and initial water salinity. The results of these experiments indicate that dispersion of montmorillonite clay is a primary contributor to formation damage. The reduction in permeability by clay dispersion may be expressed as a linear function of chloride content. Incorporating these simple functions into a radial, cross-sectional, variable-density, ground-water flow and transport model yielded a satisfactory simulation of the Norfolk field test - and represented an improvement over the model that ignored changes in permeability. This type of model offers a useful planning and design tool for ASR operations in coastal clastic aquifer systems.

  2. Atmospheric Methane Contributions From Fractured Bedrock Aquifers

    Science.gov (United States)

    Marrin, D. L.

    2013-05-01

    Groundwater is not normally considered as an important contributor of atmospheric methane because the organic carbon content of aquifers is too low to sustain significant methanogenesis. Also, groundwater-generated methane partitions into the gas phase of the overlying soil, where it either dissolves in the pore water or is oxidized to carbon dioxide by methanotrophs. There are, however, localized conditions (related to human activities and hydrogeologic conditions) under which atmospheric contributions of groundwater-generated methane occur at the ground surface. Storing and transporting liquid petroleum products in the subsurface has resulted in the local introduction of high concentrations of degradable organic carbon and the creation of redox conditions that favor methanogenesis over more oxidative biodegradation pathways. Groundwater overlain by fractured bedrock, rather than by unconsolidated porous media, creates a situation where CH4 migrates through discrete fractures, thus limiting the soil volume and the surface area available for methanotrophic activity. The spatial distribution of methane in thin surface soils overlying bedrock suggests that CH4 migrates via fracture networks and that CH4 oxidation is a factor of about 50 less than that measured in typical unconsolidated soils. Atmospheric flux rates associated with contaminated bedrock aquifers were on the order of several grams of carbon (as CH4) per square meter, which is less than that reported for well documented sources (e.g., rice paddies) and probably represents a minor worldwide contribution. Nonetheless, these aquifers can represent an important localized source, can shift soils from a sink to a source of methane, and can permit petroleum products to load carbon (as biogenic CH4 and CO2) to the atmosphere without ever being combusted.

  3. Source, variability, and transformation of nitrate in a regional karst aquifer: Edwards aquifer, central Texas.

    Science.gov (United States)

    Musgrove, Marylynn; Opsahl, Stephen P.; Mahler, Barbara J.; Herrington, Chris; Sample, Thomas; Banta, John (Ryan)

    2016-01-01

    Many karst regions are undergoing rapid population growth and expansion of urban land accompanied by increases in wastewater generation and changing patterns of nitrate (NO3−) loading to surface and groundwater. We investigate variability and sources of NO3− in a regional karst aquifer system, the Edwards aquifer of central Texas. Samples from streams recharging the aquifer, groundwater wells, and springs were collected during 2008–12 from the Barton Springs and San Antonio segments of the Edwards aquifer and analyzed for nitrogen (N) species concentrations and NO3− stable isotopes (δ15N and δ18O). These data were augmented by historical data collected from 1937 to 2007. NO3− concentrations and discharge data indicate that short-term variability (days to months) in groundwater NO3− concentrations in the Barton Springs segment is controlled by occurrence of individual storms and multi-annual wet-dry cycles, whereas the lack of short-term variability in groundwater in the San Antonio segment indicates the dominance of transport along regional flow paths. In both segments, longer-term increases (years to decades) in NO3− concentrations cannot be attributed to hydrologic conditions; rather, isotopic ratios and land-use change indicate that septic systems and land application of treated wastewater might be the source of increased loading of NO3−. These results highlight the vulnerability of karst aquifers to NO3− contamination from urban wastewater. An analysis of N-species loading in recharge and discharge for the Barton Springs segment during 2008–10 indicates an overall mass balance in total N, but recharge contains higher concentrations of organic N and lower concentrations of NO3−than does discharge, consistent with nitrification of organic N within the aquifer and consumption of dissolved oxygen. This study demonstrates that subaqueous nitrification of organic N in the aquifer, as opposed to in soils, might be a previously

  4. Ecuadorian Aquifer Studied for Marine Intrusion

    International Nuclear Information System (INIS)

    Full text: In 2007, a Technical Cooperation Project called 'Characterization of Coastal Aquifers on the Santa Elena Peninsula' (ECU8026) was launched to better assess groundwater resources in the area and investigate whether aquifers in the Santa Elena area of southwestern Ecuador (see map above) are affected by marine intrusion. The Escuela Superior Politecnica del Litoral (ESPOL), Guayaquil, Ecuador, implemented the project in collaboration with other local institutes to uncover the impact of marine intrusion, if it exists, on the sustainability of this crucial water resource. Groundwater constitutes the main source of drinking water in the area, complemented by surface water resources derived from the Santa Elena reservoir, for the local population and approximately 80 000 tourists. Due to the semi-arid climate of the area, affected by the relatively cold Humboldt stream, the coastal zones are facing important deficits in fresh groundwater, surface water and vegetation. The traditional rural water supply based on shallow dug wells and rainwater infiltration ponds (locally known as albarradas) has therefore been gradually complemented by deeper boreholes. However, intensive pumping during the past decade has led to lowering water tables and an increase in salinity, leading to the abandonment of several boreholes. Dryness is particularly pronounced in the southern zone of the Santa Elena peninsula around the city of Salinas, where mean annual rainfall amount is only 112 mm, distributed between January and April, mean annual temperatures range between 17oC and 35oC, and mean annual potential evapotranspiration is higher than 1200 mm. In the peninsula's northern zone, the phenomenon of 'garuas' (low fog and drizzling rain) may account for a slightly more humid environment. Hydrogeological Settings. The principal coastal aquifer of the Santa Elena peninsula consists of the Tablazo formation, composed of Quaternary sandstones and conglomerates, covered by alluvial

  5. Aquifer thermal energy (heat and chill) storage

    Energy Technology Data Exchange (ETDEWEB)

    Jenne, E.A. (ed.)

    1992-11-01

    As part of the 1992 Intersociety Conversion Engineering Conference, held in San Diego, California, August 3--7, 1992, the Seasonal Thermal Energy Storage Program coordinated five sessions dealing specifically with aquifer thermal energy storage technologies (ATES). Researchers from Sweden, The Netherlands, Germany, Switzerland, Denmark, Canada, and the United States presented papers on a variety of ATES related topics. With special permission from the Society of Automotive Engineers, host society for the 1992 IECEC, these papers are being republished here as a standalone summary of ATES technology status. Individual papers are indexed separately.

  6. The detection of boundaries in leaky aquifers

    International Nuclear Information System (INIS)

    Geological faults in sedimentary basins can affect the regional and local groundwater flow patterns by virtue of their enhanced permeability properties. Faults can be regarded as vertical flow boundaries and potentially important routes for radionuclide migration from a theoretical radioactive waste repository. This report investigates the hydraulic testing methods currently available which may be used to locate vertical hydraulic discontinuities (boundaries) within an aquifer. It aims to define the theoretical limitations to boundary detection by a single pumping test, to determine the optimum design of a pumping test for locating boundaries, and to define the practical limitations to boundary detection by a pumping test. (author)

  7. Localized bedrock aquifer distribution explains discharge from a headwater catchment

    Science.gov (United States)

    Kosugi, Ken'ichirou; Fujimoto, Masamitsu; Katsura, Shin'ya; Kato, Hiroyuki; Sando, Yoshiki; Mizuyama, Takahisa

    2011-07-01

    Understanding a discharge hydrograph is one of the leading interests in catchment hydrology. Recent research has provided credible information on the importance of bedrock groundwater on discharge hydrographs from headwater catchments. However, intensive monitoring of bedrock groundwater is rare in mountains with steep topography. Hence, how bedrock groundwater controls discharge from a steep headwater catchment is in dispute. In this study, we conducted long-term hydrological observations using densely located bedrock wells in a headwater catchment underlain by granitic bedrock. The catchment has steep topography affected by diastrophic activities. Results showed a fairly regionalized distribution of bedrock aquifers within a scale of tens of meters, consisting of upper, middle, and lower aquifers, instead of a gradual and continuous decline in water level from ridge to valley bottom. This was presumably attributable to the unique bedrock structure; fault lines developed in the watershed worked to form divides between the bedrock aquifers. Spatial expanse of each aquifer and the interaction among aquifers were key factors to explain gentle and considerable variations in the base flow discharge and triple-peak discharge responses of the observed hydrograph. A simple model was developed to simulate the discharge hydrograph, which computed each of the contributions from the soil mantle groundwater, from the lower aquifer, and from the middle aquifer to the discharge. The modeling results generally succeeded in reproducing the observed hydrograph. Thus, this study demonstrated that understanding regionalized bedrock aquifer distribution is pivotal for explaining discharge hydrograph from headwater catchments that have been affected by diastrophic activities.

  8. Facilitated transport of contaminant metals through an acidified aquifer

    International Nuclear Information System (INIS)

    A highly acidic aqueous waste containing metals was released into unlined seepage basins between 1955 and 1988 resulting in the contamination of the underlying aquifer. To provide insight about the mechanism(s) responsible for the facilitated movement of several of these contaminant metals, ground-water samples were recovered form the aquifer along a 1.02-km transect at approximately the rate of ground-water flow. Facilitated contaminant transport was attributed primarily to the poor cation-sorbing capacity of the aquifer matrix and the soluble nature of the metals in the acidic plume. Based on chemical equilibrium calculations of ground-water ultrafiltrates which agreed with results from cationic and anionic resin-exchange experiments, over 90% of each contaminant metal (Cr, Ni, Cu, Cd, Pb, and U) existed in cationic forms in the aquifer: either as soluble metals or a sorbates associated with positively charged ground-water colloids. These cationic species were not retained by the aquifer because the pH of the aquifer matrix was slightly below the measured point-of-zero charge, indicating the variable charge sites on the mineral surfaces within the aquifer likely had a net positive charge. Contaminants were associated with recovered ground-water colloids and this association increased with the pH of the system. However, mobile colloids would likely play only a small role in the transport of contaminants through this aquifer because of their relatively low concentration

  9. Hydrologic Properties of Aquifers in the Central Savannah River Area

    Energy Technology Data Exchange (ETDEWEB)

    Snipes, D.S.; Benson, S.M.; Price Jr., Van; Temples, T.J.

    1996-01-02

    The hydrologic properties of selected aquifer systems underlying the Milhaven and Girard sites in Georgia were determined through a series of aquifer performance tests performed from October, 1994 to January, 1995. At the Milhaven site, the systems under investigation consisted of the upper, middle and lower components of the Upper Floridan, the lower Dublin, and the lower Midville aquifers. At the Dublin site, only the lower Dublin and lower Midville aquifers were tested. In addition, the hydrologic properties of the lower Midville aquifer underlying the P, B and D Areas at the Savannah River Site were determined by a series of aquifer tests conducted in 1993 and 1994. The tests generally consisted of collecting water level and atmospheric data for 24 hours followed by a 72 hour pump test and a subsequent 72 hour recovery period. These tests were designed to determine the aquifer properties over a large area, to determine whether any hydrologic boundaries existed in the area, and to find out if leakance could be induced through the confining units which separated the aquifer units.

  10. Aquifer overexploitation: what does it mean?

    Science.gov (United States)

    Custodio, Emilio

    2002-02-01

    Groundwater overexploitation and aquifer overexploitation are terms that are becoming common in water-resources management. Hydrologists, managers and journalists use them when talking about stressed aquifers or some groundwater conflict. Overexploitation may be defined as the situation in which, for some years, average aquifer ion rate is greater than, or close to the average recharge rate. But rate and extent of recharge areas are often very uncertain. Besides, they may be modified by human activities and aquifer development. In practice, however, an aquifer is often considered as overexploited when some persistent negative results of aquifer development are felt or perceived, such as a continuous water-level drawdown, progressive water-quality deterioration, increase of ion cost, or ecological damage. But negative results do not necessarily imply that ion is greater than recharge. They may be simply due to well interferences and the long transient period that follow changes in the aquifer water balance. Groundwater storage is depleted to some extent during the transient period after ion is increased. Its duration depends on aquifer size, specific storage and permeability. Which level of "aquifer overexploitation" is advisable or bearable, depends on the detailed and updated consideration of aquifer-development effects and the measures implemented for correction. This should not be the result of applying general rules based on some indirect data. Monitoring, sound aquifer knowledge, and calculation or modelling of behaviour are needed in the framework of a set of objectives and policies. They should be established by a management institution, with the involvement of groundwater stakeholders, and take into account the environmental and social constraints. Aquifer overexploitation, which often is perceived to be associated with something ethically bad, is not necessarily detrimental if it is not permanent. It may be a step towards sustainable development. Actually

  11. Types of permeability development in limestone aquifers in Britain

    Science.gov (United States)

    Worthington, S. R. H.

    2009-04-01

    Advances over the last forty years have resulted in a clear understanding of how dissolution processes in limestone rocks enhance aquifer permeability. Laboratory experiments on dissolution rates of calcite and dolomite have established that there is a precipitous drop in dissolution rates as chemical equilibrium is approached. These results have been incorporated into numerical models, simulating the effects of dissolution over time and showing that it occurs along the entire length of pathways through limestone aquifers. The pathways become enlarged and integrated over time, forming self-organized networks of channels (or solutionally-enlarged fractures or fissures) that typically have apertures in the millimetre to centimetre range. The networks discharge at point-located springs. Numerical models that simulate dissolutional enlargement of fractures in limestone aquifers have given many insights into the conditions that favour different styles of permeability enhancement. Two end-member channel network types may be distinguished, one with many channels of similar size and one where a small number of large channels conduct most of the flow. In the latter case the larger channels may be metres in diameter (i.e. caves). Numerical modelling has shown that the former type are favoured where there is densely fractured rock, high hydraulic gradients, and recharge water close to chemical saturation (c/ceq close to 1). The latter type are favoured where there is sparsely fractured rock, low hydraulic gradients, and low values of c/ceq. These two contrasting types of aquifer have no distinguishing names in the literature. It seems reasonable to define a karst aquifer as an aquifer with self-organized, high-permeability channel networks formed by positive feedback between dissolution and flow. In this case both these aquifer types are karst aquifers. Perhaps it would be appropriate to call the former "microkarstic" aquifers and the latter "macrokarstic" aquifers. The range

  12. The surficial aquifer in Pinellas County, Florida

    Science.gov (United States)

    Causseaux, K.W.

    1985-01-01

    The surficial aquifer in Pinellas County, Florida, contains potable water throughout most of the county and is a potential source of water to augment the public supply that is presently imported from adjacent counties. The county accounts for 38 percent of the public supply consumption of ground water in the 11-county area of west-central Florida and 68 percent of this water is imported from two adjacent counties. The surficial aquifer has a saturated thickness of more than 30 feet throughout most of the county. Specific capacity per foot of screen for wells is less than 0.1 gallon per minute per foot of drawdown in some parts of the county, but yield is sufficient in most of the county for many small uses with shallow-well pumps. Minimum potential yield varies from 5 gallons per minute in the northern part of the county to more than 30 gallons per minute in the south. Concentrations of iron are high enough in parts of the county to cause staining. Chloride concentrations are less than 100 milligrams per liter in most of the county and do not pose a problem for many uses. (USGS)

  13. Hydraulic Tomography to Characterization of Heterogeneity of Unconfined Aquifers

    Science.gov (United States)

    Zhu, J.; Yeh, T. J.

    2008-12-01

    Analytical models are the most widely used methods for analyzing pumping tests in unconfined aquifers. However, one major group analytical models assume instantaneous and complete drainage at the water table and therefore are inadequate to account for gradual drainage of water from the vadose zone due to pumping; the other major group analytical models use an exponential function of drawdown at the water table to account for gradual drainage and are subsequently limited to represent the highly non-linear flow in the vadose zone. Moreover, both models assume aquifer homogeneity while the natural aquifers are inherently heterogeneous. Recently emerged Hydraulic tomography (HT) is a cost-effective method for mapping spatial distribution of aquifer hydraulic properties. HT takes advantage of the power of numerical models and fuses information from multiple cross-hole tests conducted at different locations to image aquifers in great details. In this study, we apply HT concept to unconfined aquifers. To accurately simulate the flow behavior due to a HT survey in an unconfined aquifer, a fully three dimensional variably saturated flow model based on mixed form of Richards equation is used. Pressure responses in both saturated and unsaturated zones are used to estimate spatial variations of hydraulic conductivity, specific storage, and soil water constitutive model parameters through a sequential successive linear estimator. A systematic approach that uses wavelet analysis, least-square method, and fuzzy similarity compassion is applied for data denoising, statistic inputs, convergence, and performance assessment. A cross-correlation is also performed to investigate the relation between pressure change and different parameters. The HT method for unconfined aquifers is tested in a synthetic aquifer. The tests show that the proposed HT method effectively maps heterogeneity of the unconfined aquifer and predicts the vadose zone responses due to a pumping test more accurately

  14. Geomorphic Controls on Aquifer Geometry in Northwestern India

    Science.gov (United States)

    van Dijk, W. M.; Densmore, A. L.; Sinha, R.; Gupta, S.; Mason, P. J.; Singh, A.; Joshi, S. K.; Nayak, N.; Kumar, M.; Shekhar, S.

    2014-12-01

    The Indo-Gangetic foreland basin suffers from one of the highest rates of groundwater extraction in the world, especially in the Indian states of Punjab, Haryana and Rajasthan. To understand the effects of this extraction on ground water levels, we must first understand the geometry and sedimentary architecture of the aquifer system, which in turn depend upon its geomorphic setting. We use satellite images and digital elevation models to map the geomorphology of the Sutlej and Yamuna river systems, while aquifer geometry is assessed using ~250 wells that extend to ~300 m depth in Punjab and Haryana. The Sutlej and Yamuna rivers have deposited large sedimentary fans at their outlets. Elongate downslope ridges on the fan surfaces form distributary networks that radiate from the Sutlej and Yamuna fan apices, and we interpret these ridges as paleochannel deposits associated with discrete fan lobes. Paleochannels picked out by soil moisture variations illustrate a complex late Quaternary history of channel avulsion and incision, probably associated with variations in monsoon intensity. Aquifer bodies on the Sutlej and Yamuna fans have a median thickness of 7 and 6 m, respectively, and follow a heavy-tailed distribution, probably because of stacked sand bodies. The percentage of aquifer material in individual lithologs decreases downstream, although the exponent on the thickness distribution remains the same, indicating that aquifer bodies decrease in number down fan but do not thin appreciably. Critically, the interfan area between the Sutlej and Yamuna fans has thinner aquifers and a lower proportion of aquifer material, despite its proximal location. Our data show that the Sutlej and Yamuna fan systems form the major aquifer systems in this area, and that their geomorphic setting therefore provides a first-order control on aquifer distribution and geometry. The large spatial heterogeneity of the system must be considered in any future aquifer management scheme.

  15. Management of city aquifers from anthropogenic activities: Example of the Windhoek aquifer, Namibia

    Science.gov (United States)

    Mapani, Benjamin S.; Schreiber, Ute

    As the city of Windhoek is growing rapidly, it has become increasingly obvious that dangers to the underlying groundwater aquifer have become imminent, and need addressing immediately. Water infiltration and the transportation of contaminants from anthropogenic activities through soils into the bedrock and hence the aquifer involve soil maturity, chemical and microbial processes and the climate of a particular area. The thin immature soil horizon (circa 5-20 cm) over the Windhoek schist implies that most areas of the city are built directly on bedrock, making the aquifer vulnerable. Anthropogenic activities from the use of pesticides for weed control, oil spills, toxic chemical spills, dumping of undesired substances by residents and high fertilizer application rates for lawns can lead to the contamination of groundwater. The result of our study show that the soil composition in Windhoek lacks mature clay minerals and is enriched in micas, quartz and albite. Some areas in the northern and southern industrial areas show contamination in heavy metals Pb, Zn, Cu and Ni. To the west of the city, close to the textile factory, soils are contaminated with ammonium compounds. The hydrochemistry of these pesticides and fertilizers can cause severe pollution to the groundwater if the practice is not carefully monitored. In addition, the rapid expansion of uncontrolled settlements without proper sanitation and reticulation has made the problems much more difficult. The geology of the city of Windhoek consists of the Kuiseb Schist, locally known as the “Windhoek Schist” and amphibolites. The Kuiseb schist possesses pervasive cleavage that renders the underlying lithology to be permeable to percolating water and fluids from the surface into the aquifer. The fissility and fracture density of the schist imply that leakage of surface waters, phenols, septic tank spills and industrial contaminants may reach the aquifer in unusually high rainfall years. Organic fuels and oils

  16. New solutions for the confined horizontal aquifer

    Science.gov (United States)

    Akylas, Evangelos; Gravanis, Elias

    2016-04-01

    The Boussinesq equation is a dynamical equation for the free surface of saturated subsurface flows over an impervious bed. Boussinesq equation is non-linear. The non-linearity comes from the reduction of the dimensionality of the problem: The flow is assumed to be vertically homogeneous, therefore the flow rate through a cross section of the flow is proportional to the free surface height times the hydraulic gradient, which is assumed to be equal to the slope of the free surface. In the present work we consider the case of the subsurface flow with horizontal bed. This is a case with an infinite Henderson and Wooding parameter, that is, it is the limiting case where the non-linear term is present in the Boussinesq equation while the linear spatial derivative term vanishes. Nonetheless, no analogue of the kinematic wave exists in this case as there is no exact solution for the build-up phase. Neither is there an exact recession-phase solution that holds in early times, as the Boussinesq separable solution is actually an asymptotic solution for large times. We construct approximate solutions for the horizontal aquifer which utilize directly the dynamical content of the non-linear Boussinesq equation. The approximate character of the solution lies in the fact that we start with a pre-supposed form for the solution, an educated guess, based on the nature of the initial condition as well as empirical observations from the numerical solution of the problem. The forms we shall use are power series of the location variable x along the bed with time-dependent coefficients. The series are not necessarily analytic. The boundary conditions are incorporated in the structure of the series from the beginning. The time-dependent coefficients are then determined by applying the Boussinesq equation and its spatial derivatives at the end-points of the aquifer. The forms are chosen also on the basis of their solubility; we would like to be able to construct explicitly the approximate

  17. Relationships Between Aquifer Properties and Microbial Populations in the Borden Aquifer

    DEFF Research Database (Denmark)

    Barbaro, Susan Elizabeth; Albrechtsen, Hans-Jørgen; Jensen, Bjorn K.;

    1994-01-01

    , electron transport system (ETS) activity, dissolved oxygen (DO), dissolved organic carbon (DOC), weight fraction of organic carbon (FOC), and hydraulic conductivity (K) were determined for contiguous samples of aquifer material removed at 10.0-cm intervals from the 9 cores. Viable cell counts (0-10-4 cfu...... microbiological and geologic data collected in this study suggests that, in conjunction with low dissolved oxygen, the naturally occurring carbon may be unsuitable to support large numbers of microorganisms. Similarly, an increase in the production of INT-for when aquifer material was amended with nitrogen...... activities were found to be predominantly correlated with depth and dissolved oxygen. Evaluation of these results revealed an oxygen threshold level, occurring at approximately 3.0 mg/L, below which bacterial populations isolated in this study were less able to proliferate. Further evaluation of the...

  18. Arsenic release from Floridan Aquifer rock during incubations simulating aquifer storage and recovery operations.

    Science.gov (United States)

    Jin, Jin; Zimmerman, Andrew R; Norton, Stuart B; Annable, Michael D; Harris, Willie G

    2016-05-01

    While aquifer storage and recovery (ASR) is becoming widely accepted as a way to address water supply shortages, there are concerns that it may lead to release of harmful trace elements such as arsenic (As). Thus, mechanisms of As release from limestone during ASR operations were investigated using 110-day laboratory incubations of core material collected from the Floridan Aquifer, with treatment additions of labile or refractory dissolved organic matter (DOM) or microbes. During the first experimental phase, core materials were equilibrated with native groundwater lacking in DO to simulate initial non-perturbed anaerobic aquifer conditions. Then, ASR was simulated by replacing the native groundwater in the incubations vessels with DO-rich ASR source water, with DOM or microbes added to some treatments. Finally, the vessels were opened to the atmosphere to mimic oxidizing conditions during later stages of ASR. Arsenic was released from aquifer materials, mainly during transitional periods at the beginning of each incubation stage. Most As released was during the initial anaerobic experimental phase via reductive dissolution of Fe oxides in the core materials, some or all of which may have formed during the core storage or sample preparation period. Oxidation of As-bearing Fe sulfides released smaller amounts of As during the start of later aerobic experimental phases. Additions of labile DOM fueled microbially-mediated reactions that mobilized As, while the addition of refractory DOM did not, probably due to mineral sorption of DOM that made it unavailable for microbial utilization or metal chelation. The results suggest that oscillations of groundwater redox conditions, such as might be expected to occur during an ASR operation, are the underlying cause of enhanced As release in these systems. Further, ASR operations using DOM-rich surface waters may not necessarily lead to additional As releases.

  19. Aquifer evaluation at Fenton Hill, October and November 1980

    Energy Technology Data Exchange (ETDEWEB)

    Becker, N.M.; Purtymun, W.D.; Ballance, W.C.

    1981-10-01

    An aquifer test at the Fenton Hill Geothermal Site was performed on a volcanic aquifer used for water supply. The test was made to determine the yield from the aquifer and to predict the amount of depletion that would occur with increased production during the period 1981 to 1985. A step-discharge test indicated the aquifer would comfortably yield 100 gal per min (gpm) without excessive water level drawdown in the pumping well. Drawdown test results indicated that the average aquifer transmissivity and storage coefficient are 5000 gal per day per foot (gpd/ft) and 0.07, respectively. Using these parameters, a drawdown was estimated to be at least 42 ft at the pumping well due to a withdrawal of 500 acre-ft of water over 5 yr. However, the presence of ground water boundaries indicates the aquifer is of limited extent, and because of this, the water level decline would probably be much greater. Past water level data indicate that there is little recharge to the aquifer.

  20. Impact of Aquifer Heterogeneities on Autotrophic Denitrification.

    Science.gov (United States)

    McCarthy, A.; Roques, C.; Selker, J. S.; Istok, J. D.; Pett-Ridge, J. C.

    2015-12-01

    Nitrate contamination in groundwater is a big challenge that will need to be addressed by hydrogeologists throughout the world. With a drinking water standard of 10mg/L of NO3-, innovative techniques will need to be pursued to ensure a decrease in drinking water nitrate concentration. At the pumping site scale, the influence and relationship between heterogeneous flow, mixing, and reactivity is not well understood. The purpose of this project is to incorporate both physical and chemical modeling techniques to better understand the effect of aquifer heterogeneities on autotrophic denitrification. We will investigate the link between heterogeneous hydraulic properties, transport, and the rate of autotrophic denitrification. Data collected in previous studies in laboratory experiments and pumping site scale experiments will be used to validate the models. The ultimate objective of this project is to develop a model in which such coupled processes are better understood resulting in best management practices of groundwater.

  1. Characterizaton of the Zarumilla aquifer - Peru, Ecuador

    International Nuclear Information System (INIS)

    In October 1998, Peru and Ecuador signed the Brasilia Agreements on Ecuadro-Peru border issues, representing the end of historical conflicts, differences and misunderstnadings. The two countries became partners after years of armed conflicts, and move forward through cooperation and integration, both facing social and aconomic challenges. In May 2001, the Special Bi-national Project Puyango-Tumbes (Peru) and the Ecuadorian Commission PREDESUR, province of El Oro, as technical institutes in charge of projects dealing with binational development, were invited to participate in the regional project RLA/8/031. The results of the first phase of the study are presented in this document. The study will be continued under the TC project RlA/8/039 - 'Characterization of the Zarumilla aquifer and monitoring of water quality in the Puyango-Tumbes basin'. (author)

  2. Hydrogeochemical analysis for Tasuj plain aquifer, Iran

    Indian Academy of Sciences (India)

    Ata Allah Nadiri; Asghar Asghari Moghaddam; Frank T-C Tsai; Elham Fijani

    2013-08-01

    This study investigated the hydrogeochemical processes of groundwater in the Tasuj plain, Iran. The Tasuj plain is one of the 12 marginal plains around Urmia Lake which is currently under a critical ecological condition. In the last decades, the Tasuj plain aquifer suffered from severe groundwater level declination and caused degradation of groundwater quality. To better understand hydrogeochemical processes in the Tasuj plain, this study adopted graphical methods and multivariate statistical techniques to analyze groundwater samples. A total of 504 groundwater samples was obtained from 34 different locations (qanats, wells, and springs) over 12 years (1997–2009) and analyzed for 15 water quality parameters. From the results, the Piper diagram indicated four groundwater types and the Stiff diagram showed eight different sources of groundwater samples. The Durov diagram identified five major hydrogeochemical processes in the aquifer. However, hierarchical cluster analysis (HCA) identified five water types in the groundwater samples because HCA was able to analyze more chemical and physical data than graphical methods. The HCA result was checked by discriminant analysis and found consistency in all samples that were classified into correct groups. Using factor analysis, we identified three factors that accounted for 81.6% of the total variance of the dataset. Based on the high factor loadings of the variables, factors 1 and 2 reflected the natural hydrogeochemical processes and factor 3 explained the effect of agricultural fertilizers and human activities in the Tasuj plain. Dendrograms from 2000 to 2009 were studied to understand the temporal variation of groundwater quality. Comparing the distributions of groundwater types in 2000 and 2009, we found that the mixing zone was expanded. This may be due to artificial groundwater recharge in the recharge area and the effect of inverse ion exchange in the discharge area.

  3. Exploration of a deep carbonate hydrogeothermal aquifer

    Science.gov (United States)

    von Hartmann, H.; Thomas, R.; Schulz, R.

    2009-04-01

    Geothermal energy is an increasing part of the worldwide energy supply. Deep aquifers for hydrogeothermal use must have very high porosities to provide a sufficient flow rate. The exploration of these hydrogeothermal reservoirs have to include all information which helps to predict these areas of high porosity and high permeability: lithology, facies, and structural framework. Therefore exploration techniques known from hydrocarbon exploration are used: 2D and 3D seismic surveys, including log data. A constraint is the amount of exploration costs. By which geophysical means it is possible to build a geological model which predicts the petrophysical parameters with a sufficient high possibility? There are three geological provinces in Germany with hydrogeothermal potential: the North German Basin, the Upper Rhine Graben, and the Southern German Molasse Basin. Within the Southern German Molasse Basin the hydrogeothermal aquifer comprises carbonate rocks of the Upper Jurassic which were lowered to a depth of approximately 3500 m. The interpretation of a 3D seismic survey shows the distribution of carbonate facies, structural framework, and karst formation. All three aspects are related among each other: faults can facilitate karst formation especially where reefs had been formed. Seismic attributes were used to enhance the visualization of these geologic features. The result is an overall understanding of geologic processes which formed areas of high porosity. In this way the advantage of 3D seismic surveys is obvious. Mapping of these areas can be done also within 3D seismic surveys. The appropriate choice of the seismic method depends on the exploration stage and the extent of the reservoirs. Elongated reservoirs which may be formed by carbonate solution along faults may be explored by 2D seismic lines to lower the costs of a geothermal project.

  4. Analog-digital models of stream-aquifer systems

    Science.gov (United States)

    Moulder, E.A.; Jenkins, C.T.

    1969-01-01

    The best features of analog and digital computers were combined to make a management model of a stream-aquifer system. The analog model provides a means for synthesizing, verifying, and summarizing aquifer properties; the digital model permits rapid calculation of the effects of water management practices. Given specific management alternatives, a digital program can be written that will optimize operation plans of stream-aquifer systems. The techniques are demonstrated by application to a study of the Arkansas River valley in southeastern Colorado.

  5. Review of coastal-area aquifers in Africa

    Science.gov (United States)

    Steyl, G.; Dennis, I.

    2010-02-01

    The coastal aquifer systems of Africa are comprised of various geological formations. These aquifer systems consist of either folded, continental or alluvial deposits. Groundwater resource availability along the coastal areas of Africa is briefly reported and the current state of seawater intrusion has been summarized. A select number of notable examples are given to highlight the effect of saline intrusion on coastal development of cities and regional aquifers. The role of conflict resolution is briefly discussed, as well as management approaches, which include monitoring of contamination and governmental accountability. Regional cooperation is presented as a method of ensuring a sustainable water resource in an area, as well as strengthening social and political alliances.

  6. ENVIRONMENTAL AUDITING: An Aquifer Vulnerability Assessment of the Paluxy Aquifer, Central Texas, USA, Using GIS and a Modified DRASTIC Approach.

    Science.gov (United States)

    Fritch; McKnight; Yelderman; Arnold

    2000-03-01

    / The Paluxy aquifer in north-central Texas is composed primarily of Lower Cretaceous clastics. This aquifer provides water for both domestic and agricultural purposes in the region. The study area for this investigation incorporates the outcrop and recharge areas, as well as the confined and unconfined portions of the aquifer. The purpose of this investigation is to perform a groundwater vulnerability assessment on the Paluxy aquifer using the GRASS 4.1 geographic information system combined with a modified DRASTIC approach. DRASTIC is an acronym for the variables that control the groundwater pollution potential (Depth to water, net Recharge, Aquifer media, Soil media,Topography, Impact of the vadose zone, andConductivity of the aquifer). Using such an approach allows one to investigate the potential for groundwater contamination on a regional, rather than site-specific, scale. Based upon data from variables such as soil permeability, depth to water, aquifer hydraulic conductivity, and topography, subjective numerical weightings have been assigned according to the variable's relative importance in regional groundwater quality. The weights for each variable comprise a GIS map layer. These map layers are combined to formulate the final groundwater pollution potential map. Using this method of investigation, the pollution potential map for the study area classifies 47% of the area as having low pollution potential, 26% as having moderate pollution potential, 22% as having high pollution potential, and 5% as having very high pollution potential.

  7. Finite-difference interblock transmissivity for unconfined aquifers and for aquifers having smoothly varying transmissivity

    Science.gov (United States)

    Goode, D.J.; Appel, C.A.

    1992-01-01

    More accurate alternatives to the widely used harmonic mean interblock transmissivity are proposed for block-centered finite-difference models of ground-water flow in unconfined aquifers and in aquifers having smoothly varying transmissivity. The harmonic mean is the exact interblock transmissivity for steady-state one-dimensional flow with no recharge if the transmissivity is assumed to be spatially uniform over each finite-difference block, changing abruptly at the block interface. However, the harmonic mean may be inferior to other means if transmissivity varies in a continuous or smooth manner between nodes. Alternative interblock transmissivity functions are analytically derived for the case of steady-state one-dimensional flow with no recharge. The second author has previously derived the exact interblock transmissivity, the logarithmic mean, for one-dimensional flow when transmissivity is a linear function of distance in the direction of flow. We show that the logarithmic mean transmissivity is also exact for uniform flow parallel to the direction of changing transmissivity in a two- or three-dimensional model, regardless of grid orientation relative to the flow vector. For the case of horizontal flow in a homogeneous unconfined or water-table aquifer with a horizontal bottom and with areally distributed recharge, the exact interblock transmissivity is the unweighted arithmetic mean of transmissivity at the nodes. This mean also exhibits no grid-orientation effect for unidirectional flow in a two-dimensional model. For horizontal flow in an unconfined aquifer with no recharge where hydraulic conductivity is a linear function of distance in the direction of flow the exact interblock transmissivity is the product of the arithmetic mean saturated thickness and the logarithmic mean hydraulic conductivity. For several hypothetical two- and three-dimensional cases with smoothly varying transmissivity or hydraulic conductivity, the harmonic mean is shown to yield

  8. Hydrogeology and water quality of the Floridan aquifer system and effect of Lower Floridan aquifer withdrawals on the Upper Floridan aquifer at Barbour Pointe Community, Chatham County, Georgia, 2013

    Science.gov (United States)

    Gonthier, Gerard J.; Clarke, John S.

    2016-06-02

    Two test wells were completed at the Barbour Pointe community in western Chatham County, near Savannah, Georgia, in 2013 to investigate the potential of using the Lower Floridan aquifer as a source of municipal water supply. One well was completed in the Lower Floridan aquifer at a depth of 1,080 feet (ft) below land surface; the other well was completed in the Upper Floridan aquifer at a depth of 440 ft below land surface. At the Barbour Pointe test site, the U.S. Geological Survey completed electromagnetic (EM) flowmeter surveys, collected and analyzed water samples from discrete depths, and completed a 72-hour aquifer test of the Floridan aquifer system withdrawing from the Lower Floridan aquifer.Based on drill cuttings, geophysical logs, and borehole EM flowmeter surveys collected at the Barbour Pointe test site, the Upper Floridan aquifer extends 369 to 567 ft below land surface, the middle semiconfining unit, separating the two aquifers, extends 567 to 714 ft below land surface, and the Lower Floridan aquifer extends 714 to 1,056 ft below land surface.A borehole EM flowmeter survey indicates that the Upper Floridan and Lower Floridan aquifers each contain four water-bearing zones. The EM flowmeter logs of the test hole open to the entire Floridan aquifer system indicated that the Upper Floridan aquifer contributed 91 percent of the total flow rate of 1,000 gallons per minute; the Lower Floridan aquifer contributed about 8 percent. Based on the transmissivity of the middle semiconfining unit and the Floridan aquifer system, the middle semiconfining unit probably contributed on the order of 1 percent of the total flow.Hydraulic properties of the Upper Floridan and Lower Floridan aquifers were estimated based on results of the EM flowmeter survey and a 72-hour aquifer test completed in Lower Floridan aquifer well 36Q398. The EM flowmeter data were analyzed using an AnalyzeHOLE-generated model to simulate upward borehole flow and determine the transmissivity of

  9. Monitoring technologies for the evaluation of a Soil-Aquifer-Treatment system in coastal aquifer environments.

    Science.gov (United States)

    Kallioras, Andreas; Tsertou, Athanasia; Foglia, Laura; Bumberger, Jan; Vienken, Thomas; Dietrich, Peter; Schüth, Christoph

    2014-05-01

    Artificial recharge of groundwater has an important role to play in water reuse. Treated sewage effluent can be infiltrated into the ground for recharge of aquifers. As the effluent water moves through the soil and the aquifer, it undergoes significant quality improvements through physical, chemical, and biological processes in the underground environment. Collectively, these processes and the water quality improvement obtained are called soil-aquifer-treatment (SAT) or geopurification. Recharge systems for SAT can be designed as infiltration-recovery systems, where all effluent water is recovered as such from the aquifer, or after blending with native groundwater. SAT typically removes essentially all suspended solids, biochemical oxygen demand (BOD), and pathogens (viruses, bacteria, protozoa, and helminthic eggs). Concentrations of synthetic organic carbon, phosphorous, and heavy metals are greatly reduced. The pilot site of LTCP will involve the employment of infiltration basins, which will be using waters of impaired quality as a recharge source, and hence acting as a Soil-Aquifer-Treatment, SAT, system. T he LTCP site will be employed as a pilot SAT system complemented by new technological developments, which will be providing continuous monitoring of the quantitative and qualitative characteristics of infiltrating groundwater through all hydrologic zones (i.e. surface, unsaturated and saturated zone). This will be achieved through the development and installation of an integrated system of prototype sensors, installed on-site, and offering a continuous evaluation of the performance of the SAT system. An integrated approach of the performance evaluation of any operating SAT system should aim at parallel monitoring of all hydrologic zones, proving the sustainability of all involved water quality treatment processes within unsaturated and saturated zone. Hence a prototype system of Time Domain Reflectometry (TDR) sensors will be developed, in order to achieve

  10. Factors Affecting Public-Supply Well Vulnerability in Two Karst Aquifers

    OpenAIRE

    Musgrove, MaryLynn; Katz, Brian G.; Fahlquist, Lynne S; Crandall, Christy A; Lindgren, Richard J

    2014-01-01

    Karst aquifers occur in a range of climatic and geologic settings. Nonetheless, they are commonly characterized by their vulnerability to water-quality impairment. Two karst aquifers, the Edwards aquifer in south-central Texas and the Upper Floridan aquifer in western Florida, were investigated to assess factors that control the movement of contaminants to public-supply wells (PSWs). The geochemistry of samples from a selected PSW or wellfield in each aquifer was compared with that from nearb...

  11. Digital map of aquifer boundary for the High Plains aquifer in parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set represents the extent of the High Plains aquifer in the central United States. The extent of the High Plains aquifer covers 174,000 square...

  12. Hydraulic conductivities of fractures and matrix in Slovenian carbonate aquifers

    Directory of Open Access Journals (Sweden)

    Timotej Verbovšek

    2008-12-01

    Full Text Available Hydraulic conductivities and specific storage coefficients of fractures and matrix in Slovenian carbonate aquifers were determined by Barker’s method for pumping test analysis, based on fractional flow dimension. Values are presented for limestones and mainly for dolomites, and additionally for separate aquifers, divided by age andlithology in several groups. Data was obtained from hydrogeological reports for 397 water wells, and among these, 79 pumping tests were reinterpreted. Hydraulic conductivities of fractures are higher than the hydraulic conductivities of matrix, and the differences are highly statistically significant. Likewise, differences are significant for specific storage, and the values of these coefficients are higher in the matrix. Values of all coefficients vary in separate aquifers, and the differences can be explained by diagenetic effects, crystal size, degree of fracturing, andcarbonate purity. Comparison of the methods, used in the reports, and the Barker’s method (being more suitable for karstic and fractured aquifers, shows that the latter fits real data better.

  13. Bioremediation of chlorinated ethenes in aquifer thermal energy storage

    NARCIS (Netherlands)

    Ni, Z.

    2015-01-01

      Subjects: bioremediation; biodegradation; environmental biotechnology, subsurface and groundwater contamination; biological processes; geochemistry; microbiology The combination of enhanced natural attenuation (ENA) of chlorinated volatile organic compounds (CVOCs) and aquife

  14. Hydrogeology - MO 2014 Thermoclines StFrancois Aquifer (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — St. Francois Aquifer thermo cline correlates the temperature data throughout the state in the Lower Cambrian Series, from the Bonneterre Formation to the Lamotte...

  15. Hydrogeologic Areas of the Southwest Principal Aquifer (SWPA) study

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster dataset represents the boundaries of the hydrogeologic areas of the Southwest Principal Aquifer (SWPA) study of the National Water Quality Assessment...

  16. Piedmont_and_Blue_Ridge_crystalline-rock_aquifers

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the extent of the Piedmont and Blue Ridge crystalline-rock aquifers in the states of Alabama, Delaware, District of Columbia, Georgia,...

  17. Saturated thickness of the High Plains Aquifer, Colorado, 2000

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data are in support of report DS 472 (Arnold and others, 2009). This data set represents the saturated thickness of the High Plains aquifer within Colorado....

  18. New York and New England carbonate-rock aquifers

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the extent of the New York and New England carbonate-rock aquifers in the states of New York, Vermont, Maine, Massachusetts, Connecticut,...

  19. Functional Microbial Diversity Explains Groundwater Chemistry in a Pristine Aquifer

    Science.gov (United States)

    Microbial communities inhabiting anoxic aquifers catalyze critical biogeochemical reactions in the subsurface, yet little is known about how their community structure correlates with groundwater chemistry. In this study, we described the composition of microbial communities in th...

  20. Intrinsic and enhanced biodegradation of benzene in strongly reduced aquifers

    NARCIS (Netherlands)

    Heiningen, W.N.M. van; Rijnaarts, H.H.M; Langenhoff, A.A.M.

    1999-01-01

    Laboratory microcosm studies were performed to examine intrinsic and enhanced benzene bioremediation using five different sediment and groundwater samples from three deeply anaerobic aquifers sited in northern Netherlands. The influence of addition of nitrate, sulfate, limited amounts of oxygen, and

  1. Saturated thickness of the Minnelusa aquifer, Black Hills, South Dakota.

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set is a polygon coverage created in ARC/INFO that represents the saturated thickness of the Minnelusa aquifer, Black Hills area, South Dakota. The...

  2. Saturated thickness of the Madison aquifer, Black Hills, South Dakota.

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set is a polygon coverage created in ARC/INFO that represents the saturated thickness of the Madison aquifer, which includes the entire thickness of the...

  3. Source speciation resolving hydrochemical complexity of coastal aquifers.

    Science.gov (United States)

    Sonkamble, Sahebrao; Chandra, Subash; Ahmed, Shakeel; Rangarajan, R

    2014-01-15

    There is a growing concern of seawater intrusion to freshwater aquifers due to groundwater overexploitation in the eastern coastal belt of Southern India. The problem becomes complex in the regions where industrial effluents are also contaminating the freshwater aquifers. In order to understand the hydrochemical complexity of the system, topographic elevation, static water level measurements, major ion chemistry, ionic cross plots, water type contours and factor analysis were applied for 144 groundwater samples of shallow and deep sources from Quaternary and Tertiary coastal aquifers, located within the industrial zone of 25 km(2) area near Cuddalore, Southern India. The ionic cross plots indicates dissolution of halite minerals from marine sources and seawater mixing into inland aquifers up to the level of 9.3%. The factor analysis explains three significant factors totaling 86.3% of cumulative sample variance which includes varying contribution from marine, industrial effluent and freshwater sources. PMID:24246650

  4. Delineated Aquifer Boundaries of the Lake Tahoe Basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data present a ground-water inventory of existing geospatial data and other information needed to determine the extent and characteristics of the aquifers in...

  5. Ogallala Aquifer Mapping Program. [Deaf Smith and Swisher counties

    Energy Technology Data Exchange (ETDEWEB)

    1984-10-01

    A computerized data file has been established which can be used efficiently by the contour-plotting program SURFACE II to produce maps of the Ogallala aquifer in 17 counties of the Texas Panhandle. The data collected have been evaluated and compiled into three sets, from which SURFACE II can generate maps of well control, aquifer thickness, saturated thickness, water level, and the difference between virgin (pre-1942) and recent (1979 to 1981) water levels. 29 figures, 1 table.

  6. Soil–aquifer phenomena affecting groundwater under vertisols: a review

    Directory of Open Access Journals (Sweden)

    D. Kurtzman

    2015-09-01

    Full Text Available Vertisols are cracking clayey soils that: (i usually form in alluvial lowlands where normally, groundwater pools into aquifers, (ii have different types of voids (due to cracking which make flow and transport of water, solutes and gas complex, and (iii are regarded as fertile soils in many areas. The combination of these characteristics results in the unique soil–aquifer phenomena that are highlighted and summarized in this review. The review is divided into the following four sections: (1 soil cracks as preferential pathways for water and contaminants; in this section lysimeter- to basin-scale observations that show the significance of cracks as preferential flow paths in vertisols which bypass matrix blocks in the unsaturated zone are summarized. Relatively fresh-water recharge and groundwater contamination from these fluxes and their modeling are reviewed, (2 soil cracks as deep evaporators and unsaturated-zone salinity; deep sediment samples under uncultivated vertisols in semiarid regions reveal a dry (immobile, saline matrix, partly due to enhanced evaporation through soil cracks. Observations of this phenomenon are compiled in this section and the mechanism of evapoconcentration due to air flow in the cracks is discussed, (3 impact of cultivation on flushing of the unsaturated zone and aquifer salinization; the third section examines studies reporting that land-use change of vertisols from native land to cropland promotes greater fluxes through the saline unsaturated-zone matrix, eventually flushing salts to the aquifer. Different degrees of salt flushing are assessed as well as aquifer salinization on different scales, and a comparison is made with aquifers under other soils, (4 relatively little nitrate contamination in aquifers under vertisols; In this section we turn the light on observations showing that aquifers under cultivated vertisols are somewhat resistant to groundwater contamination by nitrate (the major agriculturally

  7. FEWA: a Finite Element model of Water flow through Aquifers

    International Nuclear Information System (INIS)

    This report documents the implementation and demonstration of a Finite Element model of Water flow through Aquifers (FEWA). The particular features of FEWA are its versatility and flexibility to deal with as many real-world problems as possible. Point as well as distributed sources/sinks are included to represent recharges/pumpings and rainfall infiltrations. All sources/sinks can be transient or steady state. Prescribed hydraulic head on the Dirichlet boundaries and fluxes on Neumann or Cauchy boundaries can be time-dependent or constant. Source/sink strength over each element and node, hydraulic head at each Dirichlet boundary node, and flux at each boundary segment can vary independently of each other. Either completely confined or completely unconfined aquifers, or partially confined and partially unconfined aquifers can be dealt with effectively. Discretization of a compound region with very irregular curved boundaries is made easy by including both quadrilateral and triangular elements in the formulation. Large-field problems can be solved efficiently by including a pointwise iterative solution strategy as an optional alternative to the direct elimination solution method for the matrix equation approximating the partial differential equation of groundwater flow. FEWA also includes transient flow through confining leaky aquifers lying above and/or below the aquifer of interest. The model is verified against three simple cases to which analytical solutions are available. It is then demonstrated by two examples of how the model can be applied to heterogeneous and anisotropic aquifers with transient boundary conditions, time-dependent sources/sinks, and confining aquitards for a confined aquifer of variable thickness and for a free surface problem in an unconfined aquifer, respectively. 20 references, 25 figures, 8 tables

  8. Critical stress scenarios for a coastal aquifer in southeastern Italy

    Directory of Open Access Journals (Sweden)

    C. Cherubini

    2011-05-01

    Full Text Available Over the last years the sustainable management of coastal water resources has become strategic, especially in southern Salento Peninsula (Apulia, where mal-performing management strategies adopted, together with the vulnerability of the hydrogeological system, have given rise to the deterioration of groundwater quality due to saltwater intrusion.

    In the study area there is the presence of multilevel shallow aquifer and a deep aquifer that interact by means of faults. The geological system is highly vulnerable to seawater intrusion so there is the need to adopt management strategies to avoid seawater intrusion phenomena. Nevertheless there is a lack of studies that analyze the methodology for the correct exploitation if the water resource in order to avoid further intrusion phenomena.

    This paper combines a density-driven, flow numerical model (Seawat v.4 with a fault conceptual and hydrologic model to simulate saltwater intrusion phenomenon in the deep as well as in the shallow aquifer of the Salento area. By means of the individuation of an indicator parameter of groundwater quality, it has been possible to simulate different scenarios of exploitation and therefore to define critical stress scenarios for both aquifers.

    The results show that the deep aquifer is more vulnerable than the shallow one, which means that in the former, in order not to reach conditions of contamination, a lower density of wells is necessary than in the latter.

    The reduction of well density coupled with the artificial recharge of freshwater into the aquifer may be proposed as a solution strategy to protect the aquifer.

    Therefore, future developments of the present study will be represented by the simulation of different scenarios of recharging to inhibit the saltwater intrusion front further inland. The proposed methodology and its future developments can represent an empirical tool to provide preliminary guidelines for long

  9. Virtual groundwater transfers from overexploited aquifers in the United States.

    Science.gov (United States)

    Marston, Landon; Konar, Megan; Cai, Ximing; Troy, Tara J

    2015-07-14

    The High Plains, Mississippi Embayment, and Central Valley aquifer systems within the United States are currently being overexploited for irrigation water supplies. The unsustainable use of groundwater resources in all three aquifer systems intensified from 2000 to 2008, making it imperative that we understand the consumptive processes and forces of demand that are driving their depletion. To this end, we quantify and track agricultural virtual groundwater transfers from these overexploited aquifer systems to their final destination. Specifically, we determine which US metropolitan areas, US states, and international export destinations are currently the largest consumers of these critical aquifers. We draw upon US government data on agricultural production, irrigation, and domestic food flows, as well as modeled estimates of agricultural virtual water contents to quantify domestic transfers. Additionally, we use US port-level trade data to trace international exports from these aquifers. In 2007, virtual groundwater transfers from the High Plains, Mississippi Embayment, and Central Valley aquifer systems totaled 17.93 km(3), 9.18 km(3), and 6.81 km(3), respectively, which is comparable to the capacity of Lake Mead (35.7 km(3)), the largest surface reservoir in the United States. The vast majority (91%) of virtual groundwater transfers remains within the United States. Importantly, the cereals produced by these overexploited aquifers are critical to US food security (contributing 18.5% to domestic cereal supply). Notably, Japan relies upon cereals produced by these overexploited aquifers for 9.2% of its domestic cereal supply. These results highlight the need to understand the teleconnections between distant food demands and local agricultural water use. PMID:26124137

  10. Virtual groundwater transfers from overexploited aquifers in the United States

    Science.gov (United States)

    Marston, L.; Konar, M.; Cai, X.; Troy, T.

    2015-12-01

    The High Plains, Mississippi Embayment, and Central Valley aquifer systems within the United States are currently being overexploited for irrigation water supplies. The unsustainable use of groundwater resources in all three aquifer systems intensified from 2000 to 2008, making it imperative that we understand the consumptive processes and forces of demand that are driving their depletion. To this end, we quantify and track agricultural virtual groundwater transfers from these overexploited aquifer systems to their final destination. Specifically, we determine which US metropolitan areas, US states, and international export destinations are currently the largest consumers of these critical aquifers. We draw upon US government data on agricultural production, irrigation, and domestic food flows, as well as modeled estimates of agricultural virtual water contents to quantify domestic transfers. Additionally, we use US port-level trade data to trace international exports from these aquifers. In 2007, virtual groundwater transfers from the High Plains, Mississippi Embayment, and Central Valley aquifer systems totaled 17.93 km3, 9.18 km3, and 6.81 km3, respectively, which is comparable to the capacity of Lake Mead (35.7 km3), the largest surface reservoir in the United States. The vast majority (91%) of virtual groundwater transfers remains within the United States. Importantly, the cereals produced by these overexploited aquifers are critical to US food security (contributing 18.5% to domestic cereal supply). Notably, Japan relies upon cereals produced by these overexploited aquifers for 9.2% of its domestic cereal supply. These results highlight the need to understand the teleconnections between distant food demands and local agricultural water use.

  11. FEWA: a Finite Element model of Water flow through Aquifers

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, G.T.; Huff, D.D.

    1983-11-01

    This report documents the implementation and demonstration of a Finite Element model of Water flow through Aquifers (FEWA). The particular features of FEWA are its versatility and flexibility to deal with as many real-world problems as possible. Point as well as distributed sources/sinks are included to represent recharges/pumpings and rainfall infiltrations. All sources/sinks can be transient or steady state. Prescribed hydraulic head on the Dirichlet boundaries and fluxes on Neumann or Cauchy boundaries can be time-dependent or constant. Source/sink strength over each element and node, hydraulic head at each Dirichlet boundary node, and flux at each boundary segment can vary independently of each other. Either completely confined or completely unconfined aquifers, or partially confined and partially unconfined aquifers can be dealt with effectively. Discretization of a compound region with very irregular curved boundaries is made easy by including both quadrilateral and triangular elements in the formulation. Large-field problems can be solved efficiently by including a pointwise iterative solution strategy as an optional alternative to the direct elimination solution method for the matrix equation approximating the partial differential equation of groundwater flow. FEWA also includes transient flow through confining leaky aquifers lying above and/or below the aquifer of interest. The model is verified against three simple cases to which analytical solutions are available. It is then demonstrated by two examples of how the model can be applied to heterogeneous and anisotropic aquifers with transient boundary conditions, time-dependent sources/sinks, and confining aquitards for a confined aquifer of variable thickness and for a free surface problem in an unconfined aquifer, respectively. 20 references, 25 figures, 8 tables.

  12. Vulnerability Mapping of an Apulian Deep Carbonate Aquifer Using GIS

    OpenAIRE

    Polemio, M.; CNR-IRPI; Ricchetti, E.; Università di Bari

    1999-01-01

    Computer techniques such as Geographic Information Systems are applied to the evaluation of the vulnerability of a deep carbonate aquifer. The study area, of about 150 km2, is located in the low Murgia Plateau (Apulia) and characterized by Mesozoic limestone and dolomite rocks of several thousand meters thickness. A wide and thick aquifer resides in these carbonate rocks. Its groundwater flows toward the sea mainly under pressure and with maximum piezometric level of about 200 m a.s.l.. Du...

  13. Saline aquifer mapping project in the southeastern United States

    Science.gov (United States)

    Williams, Lester J.; Spechler, Rick M.

    2011-01-01

    In 2009, the U.S. Geological Survey initiated a study of saline aquifers in the southeastern United States to evaluate the potential use of brackish or saline water from the deeper portions of the Floridan aquifer system and the underlying Coastal Plain aquifer system (Fig. 1). The objective of this study is to improve the overall understanding of the available saline water resources for potential future development. Specific tasks are to (1) develop a digital georeferenced database of borehole geophysical data to enable analysis and characterization of saline aquifers (see locations in Fig. 1), (2) identify and map the regional extent of saline aquifer systems and describe the thickness and character of hydrologic units that compose these systems, and (3) delineate salinity variations at key well sites and along section lines to provide a regional depiction of the freshwater-saltwater interfaces. Electrical resistivity and induction logs, coupled with a variety of different porosity logs (sonic, density, and neutron), are the primary types of borehole geophysical logs being used to estimate the water quality in brackish and saline formations. The results from the geophysical log calculations are being compared to available water-quality data obtained from water wells and from drill-stem water samples collected in test wells. Overall, the saline aquifer mapping project is helping to improve the understanding of saline water resources in the area. These aquifers may be sources of large quantities of water that could be treated by using reverse osmosis or similar technologies, or they could be used for aquifer storage and recovery systems.

  14. Characterization of Aquifer Hydraulic Parameters: from Theis to Hydraulic Tomography

    OpenAIRE

    D'Oria, Marco

    2010-01-01

    Groundwater is in many parts of the world an important source of fresh water for several purpose such as domestic and industrial use and irrigation. Pollution and bad management of groundwater are only two of the problems that affect the aquifers around the world. Detailed information about the spatial distribution of hydraulic properties in subsurface are of crucial importance for a proper management of groundwater and for the prediction of the solutes transport in aquifer and therefore for ...

  15. Soil-aquifer phenomena affecting groundwater under vertisols: a review

    Science.gov (United States)

    Kurtzman, D.; Baram, S.; Dahan, O.

    2016-01-01

    Vertisols are cracking clayey soils that (i) usually form in alluvial lowlands where, normally, groundwater pools into aquifers; (ii) have different types of voids (due to cracking), which make flow and transport of water, solutes and gas complex; and (iii) are regarded as fertile soils in many areas. The combination of these characteristics results in the unique soil-aquifer phenomena that are highlighted and summarized in this review. The review is divided into the following four sections: (1) soil cracks as preferential pathways for water and contaminants: in this section lysimeter-to basin-scale observations that show the significance of cracks as preferential-flow paths in vertisols, which bypass matrix blocks in the unsaturated zone, are summarized. Relatively fresh-water recharge and groundwater contamination from these fluxes and their modeling are reviewed; (2) soil cracks as deep evaporators and unsaturated-zone salinity: deep sediment samples under uncultivated vertisols in semiarid regions reveal a dry (immobile), saline matrix, partly due to enhanced evaporation through soil cracks. Observations of this phenomenon are compiled in this section and the mechanism of evapoconcentration due to air flow in the cracks is discussed; (3) impact of cultivation on flushing of the unsaturated zone and aquifer salinization: the third section examines studies reporting that land-use change of vertisols from native land to cropland promotes greater fluxes through the saline unsaturated-zone matrix, eventually flushing salts to the aquifer. Different degrees of salt flushing are assessed as well as aquifer salinization on different scales, and a comparison is made with aquifers under other soils; (4) relatively little nitrate contamination in aquifers under vertisols: in this section we turn the light on observations showing that aquifers under cultivated vertisols are somewhat resistant to groundwater contamination by nitrate (the major agriculturally related

  16. Stochastic modeling of a lava-flow aquifer system

    Science.gov (United States)

    Cronkite-Ratcliff, Collin; Phelps, Geoffrey A.

    2014-01-01

    This report describes preliminary three-dimensional geostatistical modeling of a lava-flow aquifer system using a multiple-point geostatistical model. The purpose of this study is to provide a proof-of-concept for this modeling approach. An example of the method is demonstrated using a subset of borehole geologic data and aquifer test data from a portion of the Calico Hills Formation, a lava-flow aquifer system that partially underlies Pahute Mesa, Nevada. Groundwater movement in this aquifer system is assumed to be controlled by the spatial distribution of two geologic units—rhyolite lava flows and zeolitized tuffs. The configuration of subsurface lava flows and tuffs is largely unknown because of limited data. The spatial configuration of the lava flows and tuffs is modeled by using a multiple-point geostatistical simulation algorithm that generates a large number of alternative realizations, each honoring the available geologic data and drawn from a geologic conceptual model of the lava-flow aquifer system as represented by a training image. In order to demonstrate how results from the geostatistical model could be analyzed in terms of available hydrologic data, a numerical simulation of part of an aquifer test was applied to the realizations of the geostatistical model.

  17. Landscape irrigation management for maintaining an aquifer and economic returns.

    Science.gov (United States)

    Kovacs, Kent Forrest; Mancini, Mattia; West, Grant

    2015-09-01

    Expanding irrigated agriculture and dryer climatic conditions has led to large-scale withdrawals of groundwater and the decline in shallow aquifers. Policy makers must wrestle with the challenge of maintaining economic growth while conserving the groundwater resource. A spatially explicit landscape level model analyzes consequences of optimally chosen crop mix patterns on an aquifer and economic returns. The model of the groundwater use incorporates irrigation needs of the crops grown, initial aquifer thickness, hydro-conductivity of the aquifer, and distance to surrounding grid cells. The economic model incorporates the site specific yield, crop mix, and irrigation practice investments to predict economic returns. A tradeoff occurs between the volume of the aquifer and economic returns due to groundwater withdrawal for irrigation, but the farm's ability to grow profitable lower irrigation crops dampens the intensity of this tradeoff. Allowing for multiple unconventional irrigation practices that are yield increasing and water conserving significantly increases the economic returns of a given crop mix while maintaining the aquifer.

  18. Multiscale characterization of a heterogeneous aquifer using an ASR operation.

    Science.gov (United States)

    Pavelic, Paul; Dillon, Peter J; Simmons, Craig T

    2006-01-01

    Heterogeneity in the physical properties of an aquifer can significantly affect the viability of aquifer storage and recovery (ASR) by reducing the recoverable proportion of low-salinity water where the ambient ground water is brackish or saline. This study investigated the relationship between knowledge of heterogeneity and predictions of solute transport and recovery efficiency by combining permeability and ASR-based tracer testing with modeling. Multiscale permeability testing of a sandy limestone aquifer at an ASR trial site showed that small-scale core data give lower-bound estimates of aquifer hydraulic conductivity (K), intermediate-scale downhole flowmeter data offer valuable information on variations in K with depth, and large-scale pumping test data provide an integrated measure of the effective K that is useful to constrain ground water models. Chloride breakthrough and thermal profiling data measured during two cycles of ASR showed that the movement of injected water is predominantly within two stratigraphic layers identified from the flowmeter data. The behavior of the injectant was reasonably well simulated with a four-layer numerical model that required minimal calibration. Verification in the second cycle achieved acceptable results given the model's simplicity. Without accounting for the aquifer's layered structure, high precision could be achieved on either piezometer breakthrough or recovered water quality, but not both. This study demonstrates the merit of an integrated approach to characterizing aquifers targeted for ASR.

  19. Cave levels, safe yield and turnover time in karst aquifers

    International Nuclear Information System (INIS)

    Full text: The presence of cave levels where ground water flow is organized is a typical feature of karstic carbonate aquifers. These cave levels are high conductive paths within a capacitive matrix that differentiates flow velocities, transit times and therefore, the chemical and isotopic composition of groundwater. These two extreme transmissive end points allowed the application of double porosity models to solve flow and transport equations although actually karst aquifers are multiple-porosity systems where flow is rigorously hierarchised. The application of environmental stable and radioactive isotopic models to several Cuban karstic aquifers have shown a well defined stratification of flow varying from three months to 100 years. These so large transit times for 3H suggest that - isotopically - the system is far from steady state conditions and, therefore, the exploitation of the aquifers horizons is strongly restricted by these low renewable resources. While associated with well defined cave systems, transit time of groundwater in karst aquifers is a variable to be considered in the estimation of safe yield and in the engineering measures, as artificial recharge, designed for improve the sustainability of water resources. Depletion of water resources in karst aquifers of the humid tropics could be associated to the exploitation of isotopic 'old' waters not linked with the present hydrologic cycle. (author)

  20. Trends and Collaboration in Transboundary Aquifer Management in the Americas

    Science.gov (United States)

    Salame, L.; Stephan, R. M.

    2009-05-01

    In the framework of the UNESCO/OAS ISARM Americas project, a questionnaire on Sustainable Socioeconomic and Environmental Aspects of Transboundary Aquifers was addressed to the participating countries. The questionnaire inquired about interactions between countries sharing one or more aquifers, during the past twenty years. Forty nine transboundary aquifers are considered, based on the answers received. Very few interactions are reported; with a majority of positive ones. When competition is reported, its main reason is the quantity of water, and in some cases its quality. However the level of competition is sometimes assessed differently depending on the way it is interpreted. Reported cooperative interactions differ not only in intensity and level of success, but also in the field and range of subjects and objectives on which it has been developed; it ranges from information exchange to a complex strategic management on several subjects. In some cases, while no interactions are reported at the level of the governments, scientific cooperation is reported as a positive interaction between countries sharing an aquifer, such as in the case of most aquifers shared by Mexico and Guatemala. Countries indeed find many reasons to cooperate. The most often mentioned activities to foster cooperation are the conduction of bi or multilateral projects. The information collected lead to the conclusion that the balance of interactions over the use of shared aquifers leans towards cooperation.

  1. Digital data sets that describe aquifer characteristics of the Tillman terrace and alluvial aquifer in southwestern Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital water-level elevation contours for the Tillman terrace and alluvial aquifer in southwestern Oklahoma. The Tillman terrace and...

  2. Investigating river–aquifer relations using water temperature in an anthropized environment (Motril-Salobreña aquifer)

    DEFF Research Database (Denmark)

    Duque, Carlos; Calvache, Marie; Engesgaard, Peter Knudegaard

    2010-01-01

    . Temperature measurements in river, air, and a number of boreholes located at different distances away from the river were monitored over a 6 year period. Temperature is easy to monitor and especially useful in anthropized aquifers due to their natural and non-pollutant characteristics. The thermal responses......Heat was applied as a tracer for determining river–aquifer relations in the Motril-Salobreña aquifer (S Spain). The aquifer has typically been recharged by River Guadalfeo infiltration, nevertheless from 2005 a dam was constructed changing the traditional dynamic river flow and recharge events...... of recharge events have been analyzed with different methodologies for the characterization of the recharge process. Changes in groundwater temperatures recorded between 15 and 40 m deep are detected during the periods of higher river discharge. Temperature logs envelopes reveal areas of infiltration...

  3. Digital data sets that describe aquifer characteristics of the Tillman terrace and alluvial aquifer in southwestern Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital polygons of constant hydraulic conductivity values for the Tillman terrace and alluvial aquifer in southwestern Oklahoma. The...

  4. Digital data sets that describe aquifer characteristics of the Tillman terrace and alluvial aquifer in southwestern Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital polygons of constant recharge values for the Tillman terrace and alluvial aquifer in southwestern Oklahoma. The Tillman terrace...

  5. Uranium series geochemistry in aquifers: quantification of transport mechanisms of uranium and daughter products: the chalk aquifer (Champagne, France)

    International Nuclear Information System (INIS)

    With the increase of contaminant flux of radionuclides in surface environment (soil, river, aquifer...), there is a need to understand and model the processes that control the distribution of uranium and its daughter products during transport within aquifers. We have used U-series disequilibria as an analogue for the transport of uranium and its daughter products in aquifer to understand such mechanisms. The measurements of uranium (234U et 238U), thorium (230Th et 232Th), 226Ra and 222Rn isotopes in the solid and liquid phases of the chalk aquifer in Champagne (East of France) allows us to understand the processes responsible for fractionation within the uranium decay chain. Fractionations are induced by physical and chemical properties of the elements (leaching, adsorption) but also by radioactive properties (recoil effect during α-decay). For the first time a comprehensive sampling of the solid phase has been performed, allowing quantifying mechanisms responsible for the long term evolution of the aquifer. A non steady state 1D model has been developed which takes into account leaching, adsorption processes as well as radioactive filiation and α-recoil effect. Retardation coefficients have been calculated for uranium, thorium and radium. The aquifer is characterised by a double porosity, and the contribution of fracture and matrix porosity on the water/rock interaction processes has been estimated. (author)

  6. Commercialization of aquifer thermal energy storage technology

    Energy Technology Data Exchange (ETDEWEB)

    Hattrup, M.P.; Weijo, R.O.

    1989-09-01

    Pacific Northwest Laboratory (PNL) conducted this study for the US Department of Energy's (DOE) Office of Energy Storage and Distribution. The purpose of the study was to develop and screen a list of potential entry market applications for aquifer thermal energy storage (ATES). Several initial screening criteria were used to identify promising ATES applications. These include the existence of an energy availability/usage mismatch, the existence of many similar applications or commercial sites, the ability to utilize proven technology, the type of location, market characteristics, the size of and access to capital investment, and the number of decision makers involved. The in-depth analysis identified several additional screening criteria to consider in the selection of an entry market application. This analysis revealed that the best initial applications for ATES are those where reliability is acceptable, and relatively high temperatures are allowable. Although chill storage was the primary focus of this study, applications that are good candidates for heat ATES were also of special interest. 11 refs., 3 tabs.

  7. The economics of aquifer storage recovery technology

    Energy Technology Data Exchange (ETDEWEB)

    David, R.; Pyne, G.

    2014-10-01

    Aquifer storage recovery (ASR) technology is increasingly being utilized around the world for storing water underground through one or more wells during wet months and other times when water is available for storage. The water is then recovered from the same wells when needed to meet a growing variety of water supply objectives. The economics of ASR constitute the principal reason for its increasing utilization. ASR unit capital costs are typically less than half those of other water supply and water storage alternatives. Unit operating costs are usually only slightly greater than for conventional production well-fields. Marginal costs for ASR storage and recovery provide a powerful tool for making more efficient use of existing infrastructure, providing water supply sustainability and reliability at relatively low cost. The opportunity exists for a careful analysis of the net present value of ASR well-fields, addressing not only the associated capital and operating costs but also the value of the benefits achieved for each of the water supply objectives at each site. (Author)

  8. Soil aquifer treatment using advanced primary effluent

    KAUST Repository

    Sharma, Saroj K.

    2011-08-01

    Soil aquifer treatment (SAT) using primary effluent (PE) is an attractive option for wastewater treatment and reuse in many developing countries with no or minimal wastewater treatment. One of the main limitations of SAT of PE is rapid clogging of the infiltration basin due to high suspended solid concentrations. Some pre-treatment of PE before infiltration is likely to reduce this limitation, improve performance of SAT and help to implement this technology effectively. The effects of three pre-treatment options namely sedimentation (SED), coagulation (COAG) and horizontal roughing filtration (HRF) on SAT were analyzed by conducting laboratory-scale batch and soil column experiments. The sedimentation and coagulation pre-treatments led to less head loss development and reduction of clogging effect. The head loss development in soil column using PE + COAG and PE + SED was reduced by 85 and 72%, respectively, compared to PE alone without any pretreatment. The overall dissolved organic carbon (DOC) removal of pre-treatments and soil column collectively were 34, 44, 51 and 43.5% for PE without any pre-treatment, PE + SED, PE+ COAG and PE + HRF, respectively. Coagulation pre-treatment of PE was found to be the most effective option in terms of suspended solids, DOC and nitrogen removal. Sedimentation pre-treatment of PE could be attractive where land is relatively less expensive for the construction of sedimentation basins. © IWA Publishing 2011.

  9. Development of Managed Aquifer Recharge in China

    International Nuclear Information System (INIS)

    China has a long history in managed aquifer recharge (MAR). The historic development can be divided into 4 stages based on a summary of typical MAR projects. The first stage is MAR applied to agricultural production, the second is MAR applied to industrial production and alleviation of agricultural problems, the third is MAR applied to ecological protection and the increase in urban water supplies, and the fourth is multi-source MAR. In addition, geothermal reinjection and ground source heat pumps are also effective uses of MAR. Nevertheless, the MAR framework is defective, there is a lack of water quality studies, and the recharge rate of most projects is low. However, China has achieved a great effect on industrial and agricultural production, ecological protection, drinking water supplies and urban reclaimed water reuse, amongst others. But there are still many issues to be improved. A feasible, convenient and economic technique of MAR which fits local hydrogeological conditions needs to be developed and guidelines for both MARs and management regulations to ensure the successful running of MAR projects also need to be established. MAR will make a great difference to improving potable water quality, alleviating geological hazards, long distance water diversion, urban water supplies, agriculture irrigation, etc. (Author)

  10. Anthropogenic contaminants as tracers in an urbanizing karst aquifer

    Science.gov (United States)

    Mahler, B.; Massei, N.

    2007-01-01

    Karst aquifers are uniquely vulnerable to contamination. In the Barton Springs segment of the karstic Edwards aquifer (Texas, U.S.A.), urban contaminants such as pesticides and volatile organic compounds frequently are detected in spring base flow. To determine whether contaminant concentrations change in response to storms, and if they therefore might act as tracers of focused recharge, samples were collected from Barton Springs at closely spaced intervals following three storms. Two herbicides (atrazine and simazine), two insecticides (carbaryl and diazinon), and a solvent (tetrachloroethene) described breakthrough curves over a 1-week period following one or more storms. The breakthrough curves were decomposed into two to five log-normal subcurves, which were interpreted as representing pulses of contaminants moving through the aquifer. Each subcurve could be used in the same way as an artificial tracer to determine travel time to and recovery at the spring. The contaminants have several advantages over artificial tracers: they represent the actual compounds of interest, they are injected essentially simultaneously at several points, and they are injected under those conditions when transport is of the most interest, i.e., following storms. The response of storm discharge, specific conductance, and contaminant loading at the spring depended on initial aquifer flow conditions, which varied from very low (spring discharge of 0.48??m3/s) to high (spring discharge of 2.7??m3/s): concentrations and recovery were the highest when initial aquifer flow conditions were low. This behavior provides information about aquifer structure and the influence of aquifer flow condition on transport properties. ?? 2006 Elsevier B.V. All rights reserved.

  11. Anthropogenic contaminants as tracers in an urbanizing karst aquifer

    Science.gov (United States)

    Mahler, Barbara; Massei, Nicolas

    2007-04-01

    Karst aquifers are uniquely vulnerable to contamination. In the Barton Springs segment of the karstic Edwards aquifer (Texas, U.S.A.), urban contaminants such as pesticides and volatile organic compounds frequently are detected in spring base flow. To determine whether contaminant concentrations change in response to storms, and if they therefore might act as tracers of focused recharge, samples were collected from Barton Springs at closely spaced intervals following three storms. Two herbicides (atrazine and simazine), two insecticides (carbaryl and diazinon), and a solvent (tetrachloroethene) described breakthrough curves over a 1-week period following one or more storms. The breakthrough curves were decomposed into two to five log-normal subcurves, which were interpreted as representing pulses of contaminants moving through the aquifer. Each subcurve could be used in the same way as an artificial tracer to determine travel time to and recovery at the spring. The contaminants have several advantages over artificial tracers: they represent the actual compounds of interest, they are injected essentially simultaneously at several points, and they are injected under those conditions when transport is of the most interest, i.e., following storms. The response of storm discharge, specific conductance, and contaminant loading at the spring depended on initial aquifer flow conditions, which varied from very low (spring discharge of 0.48 m 3/s) to high (spring discharge of 2.7 m 3/s): concentrations and recovery were the highest when initial aquifer flow conditions were low. This behavior provides information about aquifer structure and the influence of aquifer flow condition on transport properties.

  12. Microbial and Geochemical Zoning of the Middendorf Aquifer, South Carolina

    Science.gov (United States)

    Jin, Q.

    2002-12-01

    The Cretaceous Middendorf aquifer in South Carolina, which extends from the Fall Line to the offshore reaches of the Atlantic Coastal plain, is distinctly zoned in both the chemical composition of the groundwater it contains and its microbial community. Groundwater flowing along the aquifer, which is confined over much of its extent, passes through a series of redox zones that have been inferred to represent segregation of the aquifer­_s microbes according to terminal electron accepting process. The zones include ecological niches supporting microbial aerobic respiration, denitrification, iron reduction, sulfate reduction, and methanogenesis. We analyzed groundwater from water supply wells across the aquifer along the direction of groundwater flow for chemical species that might serve as electron donor or acceptor for chemilithoautotrophic and acetoclastic organisms in the aquifer. These chemical species included acetate, dihydrogen, dioxygen, ferrous iron, sulfate, sulfide, nitrate, nitrite, ammonia, bicarbonate, and methane. We filtered microorganisms from water produced from these wells and then amplified their 16s rDNA genes by polymerase chain reaction (PCR) using universal Eubacterium- and Archaea-specific primers. To characterize the microbial community at each sampling location, we analyzed the amplified genes by terminal restriction fragment polymorphorism (TRFP). Sequencing of cloned genes is currently in progress. We find that along the groundwater flow path the microbial population shifts from a community dominated by bacteria to one dominated by Archaea, and that the community structure is indeed zoned by the predominant terminal electron accepting process. This zoning, furthermore, closely reflects variation along the aquifer in the thermodynamic energy available for inferred metabolisms of the observed microbes, as calculated from the results of the chemical analyses. These results provide the first direct confirmation that the chemical zoning of

  13. Isotope methods for management of shared aquifers in northern Africa.

    Science.gov (United States)

    Wallin, Bill; Gaye, Cheikh; Gourcy, Laurence; Aggarwal, Pradeep

    2005-01-01

    Access to fresh water is one of the major issues of northern and sub-Saharan Africa. The majority of the fresh water used for drinking and irrigation is obtained from large ground water basins where there is minor contemporary recharge and the aquifers cross national borders. These aquifers include the Nubian Aquifer System shared by Chad, Egypt, Libya, and Sudan; the Iullemeden Aquifer System, extending over Niger, Nigeria, Mali, Benin, and Algeria; and the Northwest Sahara Aquifer System shared by Algeria, Libya, and Tunisia. These resources are subject to increased exploitation and may be severely stressed if not managed properly as witnessed already by declining water levels. In order to make appropriate decisions for the sustainable management of these shared water resources, planners and managers in different countries need an improved knowledge base of hydrological information. Three technical cooperation projects related to aquifer systems will be implemented by the International Atomic Energy Agency, in collaboration with the United Nations Educational, Scientific and Cultural Organization and United Nations Development Programme/Global Environmental Facility. These projects focus on isotope hydrology studies to better quantify ground water recharge and dynamics. The multiple isotope approach combining commonly used isotopes 18O and 2H together with more recently developed techniques (chlorofluorocarbons, 36Cl, noble gases) will be applied to improve the conceptual model to study stratification and ground water flows. Moreover, the isotopes will be an important indicator of changes in the aquifer due to water abstraction, and therefore they will assist in the effort to establish a sustainable ground water management.

  14. Managed Aquifer Recharge Using Treated Wastewater: An Option to Manage a Coastal Aquifer In Oman For Better Domestic Water Supply

    Science.gov (United States)

    Al-Maktoumi, Ali; Zekri, Slim; ElRawy, Mustafa

    2016-04-01

    Arid countries, such as the Sultanate of Oman, are facing challenges of water shortages threatening economic development and social stability. Most of those countries are vulnerable to the potential adverse impacts of climate change, the most significant of which are increased average temperatures, less and more erratic precipitation, sea level rise, and desertification. The combined effect of existing adverse conditions and likely impacts of future climate change will make water management even more difficult than what it is today. Tremendous efforts have been devoted to augment the water resources. Managed Aquifer Recharge (MAR) is practiced widely to store water during periods of surpluses and withdraw during deficits from an aquifer. In Muscat, there will be a surplus of >100,000 m3/day of TWW during winter months in the coming few years. The aquifer along the northern coast of Oman (Al-Khawd Aquifer) is conducive for MAR. Data show that TWW volumes will increase from 7.6 Mm3 in 2003 to 70.9 Mm3 in 2035 in Muscat city only. This study assesses, using MODFLOW 2005 numerical code, the impact of MAR using TWW on better management of the Al-Khawd unconfined coastal aquifer for better urban water supply. Specifically, aiming to maximize withdrawals from the domestic wells with minimize adverse effect of seawater intrusion. The model operates under a number of constrains that minimize the loss to the sea and the injected TWW must not migrates upstream (due to developed mound) and reach the wellfields used for domestic supply. The hypothetical injection wells are located downstream the domestic wellfield zone. The results of different managerial scenarios show that MAR produces a hydraulic barrier that decelerates the seawater intrusion which allows higher abstraction of pristine water from the upstream part of the aquifer. MAR along with redistribution/relocation of public wells allows abstraction of 2 times the current abstraction rate (around 6 Mm3/year to 12 Mm3

  15. Analyzing microbial and sediment geochemistry to identify safe aquifer zones in an Arsenic prone aquifer

    Science.gov (United States)

    Kibria, G.; Hossain, M.; Kirk, M. F.; Bhattacharya, P.; Ahmed, K.; Datta, S.

    2013-12-01

    The assessment of the incidence of arsenic (As) and other oxyanions was examined in Bengal delta floodplain groundwaters from Matlab Upazila, Bangladesh. Our field campaign in 2013 covered an area of ~400km2 between North and South Matlab. Shallow tubewells except those installed within off-white sediments are mostly contaminated with high As. In our field studies we found the wells installed within light grey medium sand, the As concentration was found below 50μg/L. Groundwater abstracted from oxidized reddish sediments in contrast to reduced greyish sediments, contain significantly lower amount of dissolved As and can be a source of safe water. Sediment geochemistry and adsorption extent of oxidized red brown and reduced grey sediments to attenuate As are studied here. Sediment cores were collected at regular intervals from within depth of ~125m in Matlab. This study describes the color, lithofacies and mineralogy of the sediments The stable isotopes of groundwaters from various depths within a piezometer nest are studied also to determine the extent of hydraulic conductivity between depths of aquifers along with mechanism of recharge of the groundwater at those depths. DNA recovered from Matlab core samples averaged 450ng/g from course-grained samples and 800ng/g from fine-grained samples. After sequencing the DNA, it was found that microbial community in red or light gray sediments are different than gray-dark gray sediments (e.g. Burkholderiaceae and Pseudomonadacee are common in grey/ dark gray sediment but Streptomycetaceae is common in red/ light grey color). Rhodocyclaceae, Aeromonadaceae, Shewanellaceae are the common genera present in these sediments that are capable of reducing Fe in this aquifer environment. Synchrotron aided μXANES and μXRD studies conducted for solid state As and S speciation in the core samples at different depths indicate the occurrences of hotspots of As differently distributed in red-brown and grey sediments. Samples collected

  16. Groundwater vulnerability mapping in Guadalajara aquifers system (Western Mexico)

    Science.gov (United States)

    Rizo-Decelis, L. David; Marín, Ana I.; Andreo, Bartolomé

    2016-04-01

    Groundwater vulnerability mapping is a practical tool to implement strategies for land-use planning and sustainable socioeconomic development coherent with groundwater protection. The objective of vulnerability mapping is to identify the most vulnerable zones of catchment areas and to provide criteria for protecting the groundwater used for drinking water supply. The delineation of protection zones in fractured aquifers is a challenging task due to the heterogeneity and anisotropy of hydraulic conductivities, which makes difficult prediction of groundwater flow organization and flow velocities. Different methods of intrinsic groundwater vulnerability mapping were applied in the Atemajac-Toluquilla groundwater body, an aquifers system that covers around 1300 km2. The aquifer supplies the 30% of urban water resources of the metropolitan area of Guadalajara (Mexico), where over 4.6 million people reside. Study area is located in a complex neotectonic active volcanic region in the Santiago River Basin (Western Mexico), which influences the aquifer system underneath the city. Previous works have defined the flow dynamics and identified the origin of recharge. In addition, the mixture of fresh groundwater with hydrothermal and polluted waters have been estimated. Two main aquifers compose the multilayer system. The upper aquifer is unconfined and consists of sediments and pyroclastic materials. Recharge of this aquifer comes from rainwater and ascending vertical fluids from the lower aquifer. The lower aquifer consists of fractured basalts of Pliocene age. Formerly, the main water source has been the upper unit, which is a porous and unconsolidated unit, which acts as a semi-isotropic aquifer. Intense groundwater usage has resulted in lowering the water table in the upper aquifer. Therefore, the current groundwater extraction is carried out from the deeper aquifer and underlying bedrock units, where fracture flow predominates. Pollution indicators have been reported in

  17. Conceptual and numerical modeling approach of the Guarani Aquifer System

    Directory of Open Access Journals (Sweden)

    L. Rodríguez

    2013-01-01

    Full Text Available In large aquifers, relevant for their considerable size, regional groundwater modeling remains challenging given geologic complexity and data scarcity in space and time. Yet, it may be conjectured that regional scale groundwater flow models can help in understanding the flow system functioning and the relative magnitude of water budget components, which are important for aquifer management. The Guaraní Aquifer System is the largest transboundary aquifer in South America. It contains an enormous volume of water; however, it is not well known, being difficult to assess the impact of exploitation currently used to supply over 25 million inhabitants. This is a sensitive issue because the aquifer is shared by four countries. Moreover, an integrated groundwater model, and therefore a global water balance, were not available. In this work, a transient regional scale model for the entire aquifer based upon five simplified, equally plausible conceptual models represented by different hydraulic conductivity parametrizations is used to analyze the flow system and water balance components. Combining an increasing number of hydraulic conductivity zones and an appropriate set of boundary conditions, the hypothesis of a continuous sedimentary unit yielded errors within the calibration target in a regional sense. The magnitude of the water budget terms resulted very similar for all parametrizations. Recharge and stream/aquifer fluxes were the dominant components representing, on average, 84.2% of total inflows and 61.4% of total outflows, respectively. However, leakage was small compared to stream discharges of main rivers. For instance, the simulated average leakage for the Uruguay River was 8 m3 s−1 while the observed absolute minimum discharge was 382 m3 s−1. Streams located in heavily pumped regions switched from a gaining condition in early years to a losing condition over time. Water is discharged through

  18. Successful treatment of an MTBE-impacted aquifer using a bioreactor self-colonized by native aquifer bacteria.

    Science.gov (United States)

    Hicks, Kristin A; Schmidt, Radomir; Nickelsen, Michael G; Boyle, Susan L; Baker, Jeffrey M; Tornatore, Paul M; Hristova, Krassimira R; Scow, Kate M

    2014-02-01

    A field-scale fixed bed bioreactor was used to successfully treat an MTBE-contaminated aquifer in North Hollywood, CA without requiring inoculation with introduced bacteria. Native bacteria from the MTBE-impacted aquifer rapidly colonized the bioreactor, entering the bioreactor in the contaminated groundwater pumped from the site, and biodegraded MTBE with greater than 99 % removal efficiency. DNA sequencing of the 16S rRNA gene identified MTBE-degrading bacteria Methylibium petroleiphilum in the bioreactor. Quantitative PCR showed M. petroleiphilum enriched by three orders of magnitude in the bioreactor above densities pre-existing in the groundwater. Because treatment was carried out by indigenous rather than introduced organisms, regulatory approval was obtained for implementation of a full-scale bioreactor to continue treatment of the aquifer. In addition, after confirmation of MTBE removal in the bioreactor to below maximum contaminant limit levels (MCL; MTBE = 5 μg L(-1)), treated water was approved for reinjection back into the aquifer rather than requiring discharge to a water treatment system. This is the first treatment system in California to be approved for reinjection of biologically treated effluent into a drinking water aquifer. This study demonstrated the potential for using native microbial communities already present in the aquifer as an inoculum for ex-situ bioreactors, circumventing the need to establish non-native, non-acclimated and potentially costly inoculants. Understanding and harnessing the metabolic potential of native organisms circumvents some of the issues associated with introducing non-native organisms into drinking water aquifers, and can provide a low-cost and efficient remediation technology that can streamline future bioremediation approval processes.

  19. Shallow Aquifer Methane Gas Source Assessment

    Science.gov (United States)

    Coffin, R. B.; Murgulet, D.; Rose, P. S.; Hay, R.

    2014-12-01

    Shale gas can contribute significantly to the world's energy demand. Hydraulic fracturing (fracking) on horizontal drill lines developed over the last 15 years makes formerly inaccessible hydrocarbons economically available. From 2000 to 2035 shale gas is predicted to rise from 1% to 46% of the total natural gas for the US. A vast energy resource is available in the United States. While there is a strong financial advantage to the application of fracking there is emerging concern about environmental impacts to groundwater and air quality from improper shale fracking operations. Elevated methane (CH4) concentrations have been observed in drinking water throughout the United States where there is active horizontal drilling. Horizontal drilling and hydraulic-fracturing can increase CH4 transport to aquifers, soil and the vadose zone. Seepage can also result from casing failure in older wells. However, there is strong evidence that elevated CH4 concentrations can be associated with topographic and hydrogeologic features, rather than shale-gas extraction processes. Carbon isotope geochemistry can be applied to study CH4source(s) in shallow vadose zone and groundwater systems. A preliminary TAMU-CC isotope data set from samples taken at different locations in southern Texas shows a wide range of CH4 signatures suggesting multiple sources of methane and carbon dioxide. These data are interpreted to distinguish regions with methane contributions from deep-sourced horizontal drilling versus shallow system microbial production. Development of a thorough environmental assessment using light isotope analysis can provide understanding of shallow anthropogenic versus natural CH4sources and assist in identifying regions that require remedial actions.

  20. FEMA: a Finite Element Model of Material Transport through Aquifers

    International Nuclear Information System (INIS)

    This report documents the construction, verification, and demonstration of a Finite Element Model of Material Transport through Aquifers (FEMA). The particular features of FEMA are its versatility and flexibility to deal with as many real-world problems as possible. Mechanisms included in FEMA are: carrier fluid advection, hydrodynamic dispersion and molecular diffusion, radioactive decay, sorption, source/sinks, and degradation due to biological, chemical as well as physical processes. Three optional sorption models are embodied in FEMA. These are linear isotherm and Freundlich and Langmuir nonlinear isotherms. Point as well as distributed source/sinks are included to represent artificial injection/withdrawals and natural infiltration of precipitation. All source/sinks can be transient or steady state. Prescribed concentration on the Dirichlet boundary, given gradient on the Neumann boundary segment, and flux at each Cauchy boundary segment can vary independently of each other. The aquifer may consist of as many formations as desired. Either completely confined or completely unconfined or partially confined and partially unconfined aquifers can be dealt with effectively. FEMA also includes transient leakage to or from the aquifer of interest through confining beds from or to aquifers lying below and/or above

  1. Fundamental Elements of Geologic C02 Sequestration in Saline Aquifers

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J W; Nitao, J J; Steefel, C I

    2001-11-19

    Geologic sequestration represents a promising strategy for isolating CO{sub 2} waste streams from the atmosphere. Successful implementation of this approach hinges on our ability to predict the relative effectiveness of subsurface CO{sub 2} migration and sequestration as a function of key target-formation and cap-rock properties, which will enable us to identify optimal sites and evaluate their long-term isolation performance. Quantifying this functional relationship requires a modeling capability that explicitly couples multiphase flow and kinetically controlled geochemical processes. We have developed a unique computational package that meets these criteria, and used it to model CO{sub 2} injection at Statoil's North-Sea Sleipner facility, the world's first saline-aquifer storage site. The package integrates a state-of-the-art reactive transport simulator (NUFT) with supporting geochemical software and databases (SUPCRT92). In our Sleipner study, we have quantified--for the first time--the influence of intra-aquifer shales and aquifer/cap-rock composition on migration/sequestration balance, sequestration partitioning among hydrodynamic, solubility, and mineral trapping mechanisms, and the isolation performance of shale cap rocks. Here, we review the fundamental elements of geologic CO{sub 2} sequestration in saline aquifers as revealed from model XSH of our Sleipner study; this model, unlike CSH and DSH, does not address the complicating (yet advantageous) presence of intra-aquifer shales.

  2. ANALYTICAL SOLUTION OF GROUNDWATER FLUCTUATIONS IN ESTUARINE AQUIFER

    Institute of Scientific and Technical Information of China (English)

    CHEN Jing; ZHOU Zhi-fang; JIA Suo-bao

    2005-01-01

    As a basic factor in the environment of estuary, tidal effects in the coastal aquifer have recently attracted much attention because tidal dynamic also greatly influences the solute transport in the coastal aquifer. Previous studies on tidal dynamic of coastal aquifers have focused on the inland propagation of oceanic tides in the cross-shore direction, a configuration that is essentially one-dimensional. Two-dimensional analytical solutions for groundwater level fluctuation in recent papers are localized in presenting the effect of both oceanic tides and estuarine tides in quadrantal aquifer. A two-dimensional model of groundwater fluctuations in estuarine zone in proposed in this paper. Using complex transform, the two-dimensional flow equation subject to periodic boundary condition is changed into time-independent elliptic problem. Based on Green function method, an analytical solution for groundwater fluctuations in fan-shaped aquifer is derived. The response to of groundwater tidal loading in an estuary and ocean is discussed. The result show that its more extensive application than recent studies.

  3. FEMA: a Finite Element Model of Material Transport through Aquifers

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, G.T.; Huff, D.D.

    1985-01-01

    This report documents the construction, verification, and demonstration of a Finite Element Model of Material Transport through Aquifers (FEMA). The particular features of FEMA are its versatility and flexibility to deal with as many real-world problems as possible. Mechanisms included in FEMA are: carrier fluid advection, hydrodynamic dispersion and molecular diffusion, radioactive decay, sorption, source/sinks, and degradation due to biological, chemical as well as physical processes. Three optional sorption models are embodied in FEMA. These are linear isotherm and Freundlich and Langmuir nonlinear isotherms. Point as well as distributed source/sinks are included to represent artificial injection/withdrawals and natural infiltration of precipitation. All source/sinks can be transient or steady state. Prescribed concentration on the Dirichlet boundary, given gradient on the Neumann boundary segment, and flux at each Cauchy boundary segment can vary independently of each other. The aquifer may consist of as many formations as desired. Either completely confined or completely unconfined or partially confined and partially unconfined aquifers can be dealt with effectively. FEMA also includes transient leakage to or from the aquifer of interest through confining beds from or to aquifers lying below and/or above.

  4. Clogging in Managed Aquifer Recharge: Hydrodynamics and Geochemistry

    Science.gov (United States)

    Mays, D. C.

    2013-12-01

    Managed aquifer recharge (MAR) is the engineered process by which water is delivered into an aquifer for storage, transmission, or treatment. Perhaps the most significant technical challenge in MAR is clogging, a detrimental reduction of permeability in the aquifer porous media. This presentation describes research from the allied fields of water treatment, soil science, and petrology, each of which sheds light on the mechanisms by which hydrodynamics and geochemistry influence clogging in MAR. The primary focus is clogging by suspended solids, especially clay colloids, which are ubiquitous in natural porous media. When colloids deposit in aquifers, they reduce the effective porosity and alter the pore space geometry, both of which can inhibit the flow of groundwater. Management of clogging is complicated by the complexity inherent in this system, in which hydrodynamics, geochemistry, clay mineralogy, and colloidal effects each play a role. This presentation will briefly review colloid filtration, mobilization, and clogging models, then highlight the key physical and chemical variables that control clogging. It will be argued that clogging in managed aquifer recharge is analogous to clogging in soils or hydrocarbon reservoirs, rather than to clogging in granular media filters used for water treatment. Based on this analogy, the presentation will conclude with several recommendations to prevent or manage clogging in MAR.

  5. Optimal Groundwater Development in Coastal Aquifers Near Beihai, China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Groundwater resources occur in a multi-aquifer system in the alluvial coastal plain near Beihai, China. The aquifers receive recharge from precipitation, canal and reservoir infiltration, and discharge through subterranean drainage into the sea and through artificial pumping. A quasithree-dimensional finite element model has been used to simulate the spatial and temporal distribution of groundwater levels in the aquifers. Various input parameters were considered in the simulation model. A linear optimization model has been developed for groundwater development within the coastal aquifers. The objective function of the model is to maximize the total groundwater pumpage from the confined aquifer. The control of sea water intrusion is examined by the restriction of the water levels at points along the coast and of the pumping rates in coastal management cells. The response matrix used in the optimization model was generated from the simulation model by forecasting drawdown produced by pumping at a unit impulse discharge. Groundwater development can be primarily optimized by the alteration of the pumping rates of the existing wells.

  6. Wave-Induced Groundwater Flows in a Freshwater Beach Aquifer

    Science.gov (United States)

    Malott, S. S.; Robinson, C. E.; O'Carroll, D. M.

    2014-12-01

    Wave-induced recirculation across the sediment-water interface can impact the transport of pollutants through a beach aquifer and their ultimate flux into coastal waters. The fate of nutrients (e.g. from septic and agricultural sources) and fecal indicator bacteria (e.g. E. coil) near the sediment-water interface are of particular concern as these pollutants often lead to degradation of recreational water quality and nearshore ecosystems. This paper presents detailed field measurements of groundwater flows in a freshwater beach aquifer on Lake Huron over periods of intensified wave conditions. Quantifying wave-driven processes in a freshwater beach aquifer enables wave effects to be studied in isolation from density and tidal effects that complicate groundwater flows in marine beaches. Water exchange across the sediment-water interface and groundwater flow patterns were measured using groundwater wells, arrays of vertically nested pressure transducers and manometers. Results show that wave action induces rapid infiltration/exfiltration across the sediment-water interface and a larger recirculation cell through the beach aquifer. Field data is used to validate a numerical groundwater model of wave-induced groundwater flows. While prior studies have simulated the effects of waves on beach groundwater flows, this study is the first attempt to validate these sophisticated modeling approaches. Finally, field data illustrating the impact of wave-induced groundwater flows on nutrient and bacteria fate and transport in beach aquifers will also be presented.

  7. A generalized solution for groundwater head fluctuation in a tidal leaky aquifer system

    Indian Academy of Sciences (India)

    Mo-Hsiung Chuang; Hund-Der Yeh

    2011-12-01

    A new analytical solution is developed for describing groundwater level fluctuations in a coupled leaky confined aquifer system which consists of an unconfined aquifer, confined aquifer, and an aquitard in between. The aquifer system has a tidal boundary at the seashore, a no flow boundary at remote inland side, and a confined aquifer extending under the sea and terminated with an outlet-capping. This new solution has shown to be a generalisation of most existing analytical solutions for a tidal aquifer system which includes single confined and leaky confined aquifers. In addition, the solution is used to explore the influences of the dimensionless leakance of the outlet-capping, the dimensionless hydraulic diffusivities, and the leakages of the inland and offshore aquitards on the head responses in the leaky confined aquifer.

  8. Karst Aquifer Recharge: Comments on Somaratne, N. Characteristics of Point Recharge in Karst Aquifers. Water 2014, 6, 2782–2807

    Directory of Open Access Journals (Sweden)

    Adrian D. Werner

    2014-11-01

    Full Text Available The article “Characteristics of Point Recharge in Karst Aquifers, Water 6: 2782–2807” by N. Somaratne evaluates various recharge estimation techniques applied to four limestone aquifers in South Australia. Somaratne [1] concludes that methods based on watertable fluctuations, groundwater modelling and water budgets are independent of recharge processes, and are therefore superior to the chloride mass balance (CMB approach for karst aquifers. The current comment offers alternative interpretations from existing field measurements and previous literature, in particular for the Uley South aquifer, which is the focus of much of the article by Somaratne [1]. Conclusions regarding this system are revised, partly to account for the misrepresentation of previous studies. The aeolianite sediments of Uley South are mostly unconsolidated or poorly consolidated, and dissolution features in the calcrete capping provide point infiltration into a predominantly unconsolidated vadose zone, whereas Somaratne’s [1] findings require that the system comprises well-developed conduits in otherwise low-conductivity limestone. Somaratne’s [1] assertion that the basic premise of CMB is violated in Uley South is disputable, given strong evidence of relatively well-mixed groundwater arising from mostly diffuse recharge. The characterization of karst aquifer recharge should continue to rely on multiple techniques, including environmental tracers such as chloride.

  9. Copper and zinc distribution coefficients for sandy aquifer materials

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Astrup, Thomas; Boddum, J. K.;

    2000-01-01

    ; Zn: 6±22,800 l/kg) and correlating them to the characteristics of the aquifer material (particle size distribution, organic C content, surface area, pH) revealed good correlation with pH in the range 5.3± 8.9 (Cu: r 2=0.72; Zn: r 2=0.94). Including any other of the measured aquifer characteristics...... improved the correlation only a few percent. The results indicate that the mobility of Cu and Zn in sandy aquifers, as re¯ected in the measured Kd values, is very restricted at pH values above 6, since the relative migration velocity is less than 1%. However, at lower pH values, Zn seems to become mobile...

  10. Aquifers productivity in the Pan-African context

    Indian Academy of Sciences (India)

    Aretouyap Zakari; Nouayou Robert; Njandjock Nouck Philippe; Asfahani Jamal

    2015-04-01

    In this study, 50 Vertical Electrical Soundings (VES) were carried out in the region, including 14 near existing boreholes for comparison. Aquifer parameters of hydraulic conductivity and transmissivity were obtained by analyzing pumping test data from existing boreholes. An empirical relationship between hydraulic conductivity (K) obtained from pumping test and both resistivity and thickness of the Pan-African aquifer has been established for these boreholes in order to calculate the geophysical hydraulic conductivity. The geoelectrical interpretation shows that almost all aquifers are made of the fractured portion of the granitic bedrock located at a depth ranging between 7 and 84 m. The hydraulic conductivity varies between 0.012 and 1.677 m/day, the resistivity between 3 and 825 m, the thickness between 1 and 101 m, the transmissivity between 0.46 and 46.02 m2/day, the product K between 2.1 × 10−4 and 4.2 × 10−4.

  11. Water quality management of aquifer recharge using advanced tools.

    Science.gov (United States)

    Lazarova, Valentina; Emsellem, Yves; Paille, Julie; Glucina, Karl; Gislette, Philippe

    2011-01-01

    Managed aquifer recharge (MAR) with recycled water or other alternative resources is one of the most rapidly growing techniques that is viewed as a necessity in water-short areas. In order to better control health and environmental effects of MAR, this paper presents two case studies demonstrating how to improve water quality, enable reliable tracing of injected water and better control and manage MAR operation in the case of indirect and direct aquifer recharge. Two water quality management strategies are illustrated on two full-scale case studies, including the results of the combination of non conventional and advanced technologies for water quality improvement, comprehensive sampling and monitoring programs including emerging pollutants, tracer studies using boron isotopes and integrative aquifer 3D GIS hydraulic and hydrodispersive modelling.

  12. Isotopes to Study the coastal aquifer plain, Cap Bon, Tunisia

    International Nuclear Information System (INIS)

    The study area is located in the northeastern part of Tunisia about 60 km south of the Tunis city. It is bounded by the Gulf of Haematite in the East, Djebel Sidi Aberahmane in the West, The town of Nabeul in the south and the area of the town Kelibia in the north. The landscape is a coastal plain slightly sloping (3%) towards the sea. The groundwater of the Oriental coast aquifer system occurs mainly at two levels, a shallow aquifer up to depths of about 50 m whose reservoir is consisted by sediments of the Plio quaternary and a deep aquifer between about 150 and 400 m located in the sand stone formations of Miocene of the anticline of Djebel Sidi Abderrahmene. The climate of the region is semi-arid to sub-humid and of Mediterranean type. There are no perennial rivers in this region; but intense storms occasionally cause surface runoff, which is discharged by the oueds. The study is related to a technical cooperation project with the International Atomic Energy Agency, Vienna, Austria, aimed at the use of isotope techniques to study the seawater intrusion into the coastal aquifers of Cap Bon in Tunisia. In this regard, a better understanding of the recharge and flow regime as well as the origin or salinity of the groundwater was required. To reach this goal, isotope and geochemical investigations were carried out. Water samples were taken from wells, boreholes from deep and shallow aquifer of the Oriental coastal aquifer located between Beni Khiar in the south and Kelibia in the north. The samples were analysed for their chemical and isotopic compositions (18O, 2H, 3H, 13C, 14C, 34S). In the following, the results of these analyses are presented and discussed in terms of the recharge and flow regime of the groundwater and the origin and evolution of its salinity. The results of geochemical and isotopic studies have shown that the groundwater is very eterogeneous and suggest the aquifer is replenished by recent water coming from direct infiltration from rain. At

  13. Physical model simulations of seawater intrusion in unconfined aquifer

    Directory of Open Access Journals (Sweden)

    Tanapol Sriapai

    2012-12-01

    Full Text Available The objective of this study is to simulate the seawater intrusion into unconfined aquifer near shoreline and to assessthe effectiveness of its controlling methods by using scaled-down physical models. The intrusion controlled methods studiedhere include fresh water injection, saltwater extraction, and subsurface barrier. The results indicate that under natural dynamicequilibrium between the recharge of fresh water and the intrusion well agree with the Ghyben-Herzberg mathematical solution.Fresh water pumping from the aquifer notably move the fresh-salt water interface toward the pumping well, depending on thepumping rates and the head differences (h between the aquifer recharge and the salt water level. The fresh water injectionmethod is more favorable than the salt water extraction and subsurface barrier method. The fresh water injection rate of about10% of the usage rate can effectively push the interface toward the shoreline, and keeping the pumping well free of salinity.

  14. Modeling and Managing Regional Aquifers in Arid Countries

    Science.gov (United States)

    Schüth, C.; Rausch, R.

    2009-12-01

    Most of the regional aquifers in arid countries were recharged many thousand years ago when the climate was much wetter than today. Therefore, most of the groundwater stored in the aquifers is fossil water. The aquifers are in a state of constant depletion as recent groundwater recharge is much smaller than the outflow. A prerequisite for the smart management of such groundwater resources is a sound understanding of the aquifer system based on reliable data and robust simulation models. Mathematical groundwater models are one of the tools available that can consider a complex array of aquifer variables and allow these variables to interact with themselves. Exploring these interactions with a model can reveal how an aquifer behaves. Once a model is working properly, it can be used to make predictions for managing groundwater resources, such as predicting how groundwater levels might respond to increased pumping or drought, testing different management scenarios etc. Furthermore, groundwater models describing regional aquifers in arid regions must be considered to be in a transient state and consider the entire extent of the aquifer. The introduction of artificial boundaries is not possible and lead to wrong estimations. Within the modeling process the reduction and estimation of uncertainties is required, which leads to the “inverse problem” in groundwater modeling. Strategies for the reduction and estimation of uncertainties are needed. Problems are (1) the ill-posedness of parameter estimation, (2) that no unique solution may exist, and (3) that measurement errors make the results unreliable. Ways out are the reduction of degrees of freedom by introducing geological ‘a priori’ knowledge as well as the joint use of head, flow and/or concentration measurements, and the estimation of uncertainty. This concept is demonstrated by examples of model development for regional aquifers on the Arabian Peninsula, e.g. ‘a priori’ knowledge is introduced into the

  15. A computer program (MACPUMP) for interactive aquifer-test analysis

    Science.gov (United States)

    Day-Lewis, F. D.; Person, M.A.; Konikow, L.F.

    1995-01-01

    This report introduces MACPUMP (Version 1.0), an aquifer-test-analysis package for use with Macintosh4 computers. The report outlines the input- data format, describes the solutions encoded in the program, explains the menu-items, and offers a tutorial illustrating the use of the program. The package reads list-directed aquifer-test data from a file, plots the data to the screen, generates and plots type curves for several different test conditions, and allows mouse-controlled curve matching. MACPUMP features pull-down menus, a simple text viewer for displaying data-files, and optional on-line help windows. This version includes the analytical solutions for nonleaky and leaky confined aquifers, using both type curves and straight-line methods, and for the analysis of single-well slug tests using type curves. An executable version of the code and sample input data sets are included on an accompanying floppy disk.

  16. Geochemical and isotopic composition of ground water with emphasis on sources of sulfate in the upper Floridan Aquifer and intermediate aquifer system in southwest Florida

    Science.gov (United States)

    Sacks, Laura A.; Tihansky, Ann B.

    1996-01-01

    In southwest Florida, sulfate concentrations in water from the Upper Floridan aquifer and overlying intermediate aquifer system are commonly above 250 milligrams per liter (the drinking water standard), particularly in coastal areas. Possible sources of sulfate include dissolution of gypsum from the deeper part of the Upper Floridan aquifer or the middle confining unit, saltwater in the aquifer, and saline waters from the middle confining unit and Lower Floridan aquifer. The sources of sulfate and geochemical processes controlling ground-water composition were evaluated for the Peace and Myakka River Basins and adjacent coastal areas of southwest Florida. Samples were collected from 63 wells and a saline spring, including wells finished at different depth intervals of the Upper Floridan aquifer and intermediate aquifer system at about 25 locations. Sampling focused along three ground-water flow paths (selected based on a predevelopment potentiometric-surface map). Ground water was analyzed for major ions, selected trace constituents, dissolved organic carbon, and stable isotopes (delta deuterium, oxygen-18, carbon-13 of inorganic carbon, and sulfur-34 of sulfate and sulfide); the ratio of strontium-87 to strontium-86 was analyzed for waters along one of the flow paths. Chemical and isotopic data indicate that dedolomitization reactions (gypsum and dolomite dissolution and calcite precipitation) control the chemical composition of water in the Upper Floridan aquifer in inland areas. This is confirmed by mass-balance modeling between wells in the shallowest interval in the aquifer along the flow paths. However, gypsum occurs deeper in the aquifer than these wells. Upwelling of sulfate-rich water that previously dissolved gypsum in deeper parts of the aquifer is a more likely source of sulfate than gypsum dissolution in shallow parts of the aquifer. This deep ground water moves to shallower zones in the aquifer discharge area. Saltwater from the Upper Floridan aquifer

  17. Mobilization and micellar solubilization of NAPL contaminants in aquifer rocks.

    Science.gov (United States)

    Javanbakht, Gina; Goual, Lamia

    2016-01-01

    Surfactant-enhanced aquifer remediation is often performed to overcome the capillary forces that keep residual NAPL phases trapped within contaminated aquifers. The surfactant selection and displacement mechanism usually depend on the nature of NAPL constituents. For example, micellar solubilization is often used to cleanup DNAPLs from aquifers whereas mobilization is desirable in aquifers contaminated by LNAPLs. Although the majority of crude oils are LNAPLs, they often contain heavy organic macromolecules such as asphaltenes that are classified as DNAPLs. Asphaltenes contain surface-active components that tend to adsorb on rocks, altering their wettability. Previous studies revealed that surfactants that formed Winsor type III microemulsions could promote both mobilization and solubilization. However the extent by which these two mechanisms occur is still unclear, particularly in oil-contaminated aquifers. In this study we investigated the remediation of oil-contaminated aquifers using an environmentally friendly surfactant such as n-Dodecyl β-D-maltoside. Focus was given on asphaltenes to better understand the mechanisms of surfactant cleanup. Through phase behavior, spontaneous imbibition, dynamic interfacial tension and contact angle measurements, we showed that microemulsions formed by this surfactant are able to mobilize bulk NAPL (containing 9wt.% asphaltenes) in the porous rock and solubilize DNAPL (i.e., 4-6wt.% adsorbed asphaltenes) from the rock surface. Spontaneous imbibition tests, in particular, indicated that the ratio of mobilized to solubilized NAPL is about 6:1. Furthermore, aging the cores in NAPL beyond 3days allowed for more NAPL to be trapped in the large pores of the rock but did not alter the amount of asphaltenes adsorbed on the mineral surface. PMID:26826983

  18. Pollution of an aquifer by produced oil field water

    International Nuclear Information System (INIS)

    Brine is produced from reservoirs as a waste material from crude oil and gas after processing. Waste water may be discharged at the surface or reinjected underground. When it is reinjected, it may be mixed with an underground fresh water source for several reasons. From this point of view, forecasting the pollutant concentrations by knowing the historical data at several locations on a field has great importance when planning the necessary precautions for environmental safety. Aquifer-M in Turkey, having the properties of potable water, is contaminated by oil field water that is injected for disposal purposes. A numerical model is used to determine the extent of pollution due to the injection of saline produced water into aquifer-M. Eight observation wells are drilled to take water and core samples in order to identify both rock and fluid properties of aquifer-M. Water samples taken from different intervals of aquifer-M are analyzed to determine the flow paths for the pollutant movement. The results are interpreted with the help of core property data obtained by computerized tomography (CT) analysis and routine core analysis. By using drilling records, log data, and CT analysis results, two subunits in aquifer-M with different lithological properties are identified. All data are used in a ground water pollution model. Aquifer-M has fresh water with salinity of 5-10 ppm, and the chlorine concentration of injected waste water is approximately 3410 pp. Since there is a significant difference between these concentrations, the chlorine ion is selected as the indicative ion for locating the pollution front. The model study indicated that the contaminated water has propagated 18.7 km from the site of injection. (author)

  19. Mobilization and micellar solubilization of NAPL contaminants in aquifer rocks

    Science.gov (United States)

    Javanbakht, Gina; Goual, Lamia

    2016-02-01

    Surfactant-enhanced aquifer remediation is often performed to overcome the capillary forces that keep residual NAPL phases trapped within contaminated aquifers. The surfactant selection and displacement mechanism usually depend on the nature of NAPL constituents. For example, micellar solubilization is often used to cleanup DNAPLs from aquifers whereas mobilization is desirable in aquifers contaminated by LNAPLs. Although the majority of crude oils are LNAPLs, they often contain heavy organic macromolecules such as asphaltenes that are classified as DNAPLs. Asphaltenes contain surface-active components that tend to adsorb on rocks, altering their wettability. Previous studies revealed that surfactants that formed Winsor type III microemulsions could promote both mobilization and solubilization. However the extent by which these two mechanisms occur is still unclear, particularly in oil-contaminated aquifers. In this study we investigated the remediation of oil-contaminated aquifers using an environmentally friendly surfactant such as n-Dodecyl β-D-maltoside. Focus was given on asphaltenes to better understand the mechanisms of surfactant cleanup. Through phase behavior, spontaneous imbibition, dynamic interfacial tension and contact angle measurements, we showed that microemulsions formed by this surfactant are able to mobilize bulk NAPL (containing 9 wt.% asphaltenes) in the porous rock and solubilize DNAPL (i.e., 4-6 wt.% adsorbed asphaltenes) from the rock surface. Spontaneous imbibition tests, in particular, indicated that the ratio of mobilized to solubilized NAPL is about 6:1. Furthermore, aging the cores in NAPL beyond 3 days allowed for more NAPL to be trapped in the large pores of the rock but did not alter the amount of asphaltenes adsorbed on the mineral surface.

  20. Localized sulfate-reducing zones in a coastal plain aquifer

    Science.gov (United States)

    Brown, C.J.; Coates, J.D.; Schoonen, M.A.A.

    1999-01-01

    High concentrations of dissolved iron in ground water of coastal plain or alluvial aquifers contribute to the biofouling of public supply wells for which treatment and remediation is costly. Many of these aquifers, however, contain zones in which microbial sulfate reduction and the associated precipitation of iron-sulfide minerals decreases iron mobility. The principal water-bearing aquifer (Magothy Aquifer of Cretaceous age) in Suffolk County, New York, contains localized sulfate-reducing zones in and near lignite deposits, which generally are associated with clay lenses. Microbial analyses of core samples amended with [14C]-acetate indicate that microbial sulfate reduction is the predominant terminal-electron-accepting process (TEAP) in poorly permeable, lignite-rich sediments at shallow depths and near the ground water divide. The sulfate-reducing zones are characterized by abundant lignite and iron-sulfide minerals, low concentrations of Fe(III) oxyhydroxides, and by proximity to clay lenses that contain pore water with relatively high concentrations of sulfate and dissolved organic carbon. The low permeability of these zones and, hence, the long residence time of ground water within them, permit the preservation and (or) allow the formation of iron-sulfide minerals, including pyrite and marcasite. Both sulfate-reducing bacteria (SRB) and iron-reducing bacteria (IRB) are present beneath and beyond the shallow sulfate-reducing zones. A unique Fe(III)-reducing organism, MD-612, was found in core sediments from a depth of 187 m near the southern shore of Long Island. The distribution of poorly permeable, lignite-rich, sulfate-reducing zones with decreased iron concentration is varied within the principal aquifer and accounts for the observed distribution of dissolved sulfate, iron, and iron sulfides in the aquifer. Locating such zones for the placement of production wells would be difficult, however, because these zones are of limited aerial extent.

  1. Incorporating transient storage in conjunctive stream-aquifer modeling

    Science.gov (United States)

    Lin, Yi-Chang; Medina, Miguel A.

    2003-09-01

    There has been growing interest in incorporating the transient storage effect into modeling solute transport in streams. In particular, for a smaller mountain stream where flow is fast and the flow field is irregular (a favorable environment to induce dead zones along the stream), long tails are normally observed in the stream tracer data, and adding transient storage terms in the advection-dispersion transport equation can result in more accurate simulation. While previous studies on transient storage modeling account for temporary, localized exchange between the stream and the shallow groundwater in the hyporheic zone, larger-scale exchange with the groundwater in the underlying aquifer has rarely been included or properly coupled to surface water modeling. In this paper, we complement previous modeling efforts by incorporating the transient storage concept in a conjunctive stream-aquifer model. Three well-documented and widely used USGS models have been coupled to form the core of this conjunctive model: MODFLOW handles the groundwater flow in the aquifer; DAFLOW accurately computes unsteady streamflow by means of the diffusive wave routing technique, as well as stream-aquifer exchange simulated as streambed leakage; and MOC3D computes solute transport in the groundwater zone. In addition, an explicit finite difference package was developed to incorporate the one-dimensional transient storage equations for solute transport in streams. The quadratic upstream interpolation (QUICK) algorithm is employed to improve the accuracy of spatial differencing. An adaptive stepsize control algorithm for the Runge-Kutta method is incorporated to increase overall model efficiency. Results show that the conjunctive stream-aquifer model with transient storage can handle well the bank storage effect under a flooding event. When it is applied over a stream network, the results also show that the stream-aquifer interaction acts as a strong source or sink along the stream and is too

  2. A heat and dye tracer test for characterizing and modelling heat transfer in an alluvial aquifer

    OpenAIRE

    Klepikova, Maria; Wildemeersch, Samuel; Jamin, Pierre; Orban, Philippe; Hermans, Thomas; Brouyère, Serge; Dassargues, Alain

    2014-01-01

    Using heat as an active tracer is a topic of increasing interest with regards to characterizing shallow aquifers for ATES (Aquifer Thermal Energy Storage) systems. In this study, we investigate the potential interest of coupling simultaneous heat and dye tracer injection tests for characterization of an alluvial aquifer. The study site is located near Liege in the alluvial aquifer of the Meuse River, Belgium. The tracing experiment consisted in simultaneously injecting heated water and a dye ...

  3. Origin and residence time of water in the Lima Aquifer

    CERN Document Server

    Montoya, Modesto

    2014-01-01

    The 8 million inhabitants of the coast Lima City are supplied with water from Rimac and Chillons rivers and water wells in the Lima aquifer. Historics of Rimac River flow and static level of water level in wells are correlated in order to calculate residence time of water since the aquifer is recharged by Rimac River until water reaches a well located 12 km farther, in Miraflores district near sea. Relative abundances of 2H and 18O are used to identify origins of waters from those wells. 3H and 14C contents, respectively, are used to estimate ages of waters.

  4. Isotopic hydrodynamic of the aquifer systems Jaruco and Aguacate, Cuba

    International Nuclear Information System (INIS)

    An isotopic dispersive model is applied to the Jaruco and Aguacate karstic groundwater basins of Western Cuba. The best fit of the model was validated with stable (18O and 2H) and radioactive (3H) isotopes. Modeling showed an aquifer stratification in two basic levels with turnover times of three month to upper level and close to 100 years to the lower level. The last one mainly supplies the base flow of the Ojo de agua and Bello springs and therefore, controls the dry season exploitation yields of the aqueducts of El Gato and Bello. Model results introduces an important constraint in the exploitation of groundwater resource of both aquifer systems

  5. Legal and regulatory issues affecting aquifer thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Hendrickson, P.L.

    1981-10-01

    This document updates and expands the report with a similar title issued in October 1980. This document examines a number of legal and regulatory issues that potentially can affect implementation of the aquifer thermal energy storage (ATES) concept. This concept involves the storage of thermal energy in an underground aquifer until a later date when it can be effectively utilized. Either heat energy or chill can be stored. Potential end uses of the energy include district space heating and cooling, industrial process applications, and use in agriculture or aquaculture. Issues are examined in four categories: regulatory requirements, property rights, potential liability, and issues related to heat or chill delivery.

  6. Constraining nitrogen cycling hotspots in contaminated aquifers

    Science.gov (United States)

    Wells, Naomi; Knoeller, Kay

    2014-05-01

    Accurate assessments of the fate of inorganic nitrogen (N) in groundwater are needed in order to mitigate the threat that ammonium (NH4+) and nitrate (NO3-) pose to water quality and the long-term health of down-gradient ecosystems. However, such assessments are currently limited by difficulties in measuring the biological attenuation (via either denitrification or anaerobic ammonia oxidation (anammox)) of these reactive species in-situ. Based on the knowledge that both of these processes can create unique fractionation patterns in the residual N pools, the objective of this research was to build a template for identifying and quantifying N removal hotspots within complex aquifers using isofluxes. The variations in concentration and isotopic abundance of multiple dissolved inorganic N species (δ15N of NH4+, and δ15N and δ18O of NO2- and NO3-) were measured in 100 wells across two contaminated megasites in Western Europe. The sampling locations were selected span the NH4+ (the dominant N form in both sites) concentration gradient (0 to 900 mg NH4+-N l-1) over depth and distance, which coincided with gradients in co-contaminants BTEX and sulphate of 0 to 5 mg l-1 4 to 11000 mg l-1, respectively. Although NO2- is a key component of both anaerobic and aerobic ammonium oxidation, it is rarely detected in groundwater. Yet, by analysing for it on-site, we found that NO2- concentrations reached up to 0.7 mg NO2-N l-1 and had a highly sensitive isotopic composition (mean of -5 ±23o (δ15N) and +11 ±12o (δ18O)). The largest NO2- concentrations coincided with those of NH4+ levels, meaning that attenuation fluxes could be partitioned between anammox and denitrification using simple isotope mass balance calculations based on Rayleigh type isotope fractionation and established nitrate (δ15N and δ18O) isotope dynamics during denitrification. The constraints on N attenuation within these complex hydrological and chemical setting created by overlaying isoflux maps for each

  7. Using pressure and volumetric approaches to estimate CO2 storage capacity in deep saline aquifers

    NARCIS (Netherlands)

    Thibeau, S.; Bachu, S.; Birkholzer, J.; Holloway, S.; Neele, F.P.; Zou, Q.

    2014-01-01

    Various approaches are used to evaluate the capacity of saline aquifers to store CO2, resulting in a wide range of capacity estimates for a given aquifer. The two approaches most used are the volumetric “open aquifer” and “closed aquifer” approaches. We present four full-scale aquifer cases, where C

  8. Characterization of the sediments overlying the Floridan aquifer system in Alachua County, Florida

    OpenAIRE

    Green, Richard; Duncan, Joel; Seal, Thomas; Weinberg, J. Michael; Rupert, Frank

    1989-01-01

    The primary purpose of this project is to attempt to improve the existing hydrogeologic information through lithologic and hydrogeologic characterizations of the sediments overlying the Floridan aquifer system in Alachua County. These sediments locally comprise both the intermediate aquifer system and associated confining beds and the surficial aquifer system. (PDF has 119 pages.)

  9. Modeling groundwater levels on the Calera Aquifer Region in Central Mexico using ModFLow.

    Science.gov (United States)

    A conceptual model for the Calera Aquifer has been created to represent the aquifer system beneath the Calera Aquifer Region (CAR) in the State of Zacatecas, Mexico. The CAR area was uniformly partitioned into a 500 X 500 m grid generating a high resolution model that represented the natural boundar...

  10. Young and old water in global rivers and aquifers

    Science.gov (United States)

    Jasechko, S.; Kirchner, J. W.; McDonnell, J.; Gleeson, T. P.; Befus, K. M.; Luijendijk, E.; Cardenas, M. B.; Wada, Y.; Welker, J. M.

    2015-12-01

    The fate of solutes, nutrients and contaminants are regulated by the time that precipitation takes to travel through landscapes to reach surface waters and aquifers. Water samples collected from a stream or a groundwater well are a mixture of younger and older precipitation inputs. However, the global 3D distribution of younger versus older water flowing in rivers or stored in groundwater aquifers is not known, in part due to a longstanding focus on average age rather than age distributions. Here we analyze global rain, snow, groundwater and streamflow isotope contents, compiled from primary literature sources or specialist databases. Instead of calculating average water ages, we use the isotope data to partition fractions of younger versus older water in 260 rivers and 202 aquifers. For global rivers, we show that precipitation reaching the stream in less than 1.5-3 months generates a substantial fraction (~35%) of global runoff and constitutes an important component (>5%) of streamflow draining the great majority (90%) of watersheds. We also show that ~35% of global runoff is generated by a microscopic fraction (50%) groundwaters are relicts of ancient climates, having recharged their aquifers prior to the current Holocene epoch. Our study, that partitions both surface- and ground-water ages, shows that much of global streamflow is at least four orders of magnitude younger than most of global groundwater storage, highlighting that most stream water is far younger than most groundwater stored in their catchments.

  11. Methanotrophic Bacteria and Facilitated Transport of Pollutants in Aquifer Material

    OpenAIRE

    Jenkins, Michael B.; Chen, Jyh-Herng; Kadner, Debra J.; Lion, Leonard W.

    1994-01-01

    In situ stimulation of methanotrophic bacteria has been considered as a methodology for aquifer remediation. Chlorinated aliphatic hydrocarbons such as trichloroethylene are fortuitously oxidized by the methane monooxygenase produced by methanotrophic bacteria. Experimental results are presented that indicate that both colloidal suspensions containing methanotrophic cells and the soluble extracellular polymers produced by methanotrophic cells have the potential to enhance the transport and re...

  12. Sustainable yields from large diameter wells in shallow weathered aquifers

    Science.gov (United States)

    Rushton, K. R.; de Silva, C. S.

    2016-08-01

    Large diameter wells in shallow weathered aquifers provide a valuable source of water for domestic and agricultural purposes in many locations including the Indian subcontinent. However, when used for irrigation, these wells often fail towards the end of the dry season. By considering two case studies in the dry and intermediate rainfall zones of Sri Lanka, reasons for the limited yield of these wells are identified. The first case study is concerned with a sloping catchment; a significant proportion of the precipitation during the rainy season either becomes runoff or passes down-gradient through the aquifer and is discharged at the ground surface. Furthermore, during the dry season, groundwater discharge continues. In the second case study the topography is generally flat but, even though the aquifer fills most years during the rainy season, there is often only sufficient water to irrigate about half of each farmer's holding. These investigations are based on field information and the development of conceptual and computational models. Of critical importance in assessing the long term yield of a well is the formation of a seepage face on the side of the well, with the water table a significant distance above the pumping water level. Consequently the water table may only be lowered to about half the depth of the well. The paper concludes with recommendations for the exploitation of groundwater from shallow weathered aquifers to minimise the risk of failure during the dry season.

  13. Bioremediation of chlorinated ethenes in aquifer thermal energy storage

    OpenAIRE

    Ni, Z

    2015-01-01

      Subjects: bioremediation; biodegradation; environmental biotechnology, subsurface and groundwater contamination; biological processes; geochemistry; microbiology The combination of enhanced natural attenuation (ENA) of chlorinated volatile organic compounds (CVOCs) and aquifer thermal energy storage (ATES) appears attractive because such integration provides a promising solution for redevelopment of urban areas in terms of improving the local environmental quality as well as achieving ...

  14. Spatial organization of the impulse response in a karst aquifer

    Science.gov (United States)

    Delbart, C.; Valdés, D.; Barbecot, F.; Tognelli, A.; Couchoux, L.

    2016-06-01

    Karst aquifers are characterized by a strong heterogeneity in their physical properties. The purpose of the study is the spatial variability of water transfers in a carbonated karstic aquifer. To this end, a high spatial density of information about the water transfer is needed. The characteristics of the site, a topographic hill of 13 km2 with eight boreholes, which was monitored hourly over four years, allows the study of the spatial variability of water transfers. The variability of the impulse response of the system is studied using autocorrelation and cross-correlation analysis between the rainfall and piezometric level time series. The shapes of the autocorrelation and cross-correlation functions vary according to the geographical location of the boreholes, that proves a spatial organization of the groundwater transfer. The response time varies depending on the thickness of the unsaturated zone by an unusual inverse correlation. In this case, the water level signal spatially integrates the signal transfer of the unsaturated zone and the signal transfer of the saturated part of the aquifer. Consequently, inertia and response time increased with the distance between the borehole and the top of piezometric dome. This description supports highly organized fast transfers in this karst aquifer and a highly connected fracture network.

  15. Investigating groundwater arsenic contamination using aquifer push-pull test

    Science.gov (United States)

    Daigle, A. R.; Jin, Q.

    2009-12-01

    The groundwater of the Southern Willamette Basin, OR is contaminated with arsenic at concentrations as high as several ppm. A single-well push-pull test was conducted to investigate how microbial metabolisms control arsenic occurrence and levels in the bedrock aquifer of the area. During the experiments, a test solution containing ethanol was first injected into the aquifer. As the experiment progressed, dissolved gasses, groundwater, and sediment were sampled to monitor the variations in the chemical parameters, including the speciation of iron, sulfur, and arsenic, in the aquifer. Ethanol amendment stimulated a series of microbial metabolisms, including arsenate reduction, iron reduction, and sulfate reduction. Iron reduction released arsenic sorbed onto the aquifer sediments, increasing groundwater arsenic levels. Arsenate reduction converted arsenate to arsenite and, as a result, most arsenic occurred as arsenite in the groundwater. Results of the experiments demonstrate how different microbial functional groups influenced arsenic contamination in the area. These results also shed new light on potential bioremediation strategies in the area.

  16. Extended geothermal potential of clastic aquifers by hydraulic stimulation

    NARCIS (Netherlands)

    Veldkamp, J.G.; Pluymaekers, M.P.D.; Wees, J.D.A.M.

    2014-01-01

    We evaluated the implications of hydraulic stimulation in a Dutch context for low permeability clastic aquifers at a depth of 2000 to 4000 m, whose transmissivity has been mapped in the framework of the Dutch subsurface information system on geothermal energy in the Netherlands. For the simulation a

  17. Patterns of groundwater quality in sandy aquifers under environmental pressure

    NARCIS (Netherlands)

    Vissers, M.J.M.

    2006-01-01

    In exploring groundwater quality patterns in sandy phreatic aquifers this thesis follows three fundamental tracks, which are of a methodological, of a conceptual, and of a process based kind. First, in chapter 1 the three principle factors that together determine the groundwater quality distribution

  18. Large-Scale Experiments in a Sandy Aquifer in Denmark

    DEFF Research Database (Denmark)

    Jensen, Karsten Høgh; Bitsch, Karen Bue; Bjerg, Poul Løgstrup

    1993-01-01

    distance for distances between 50 and 200 m could be found, suggesting that the asymptotic stage was reached within a short distance from the point of injection. A three-dimensional numerical model for flow and transport was applied to the aquifer in order to quantify the dispersivity parameters more...

  19. Reactivity of Organic Matter and other Reductants in Aquifer Sediments

    NARCIS (Netherlands)

    Hartog, N.

    2003-01-01

    The molecular composition and the carbon isotope signature of sedimentary organic matter (SOM) and indicate that SOM is predominantly derived from higher land plants in sediments of both terrestrial as marine origins. The reactivity of SOM in the aquifer sediments studied is determined by the extent

  20. Geochemical detection of carbon dioxide in dilute aquifers

    Energy Technology Data Exchange (ETDEWEB)

    Carroll, S; Hao, Y; Aines, R

    2009-03-27

    Carbon storage in deep saline reservoirs has the potential to lower the amount of CO{sub 2} emitted to the atmosphere and to mitigate global warming. Leakage back to the atmosphere through abandoned wells and along faults would reduce the efficiency of carbon storage, possibly leading to health and ecological hazards at the ground surface, and possibly impacting water quality of near-surface dilute aquifers. We use static equilibrium and reactive transport simulations to test the hypothesis that perturbations in water chemistry associated with a CO{sub 2} gas leak into dilute groundwater are important measures for the potential release of CO{sub 2} to the atmosphere. Simulation parameters are constrained by groundwater chemistry, flow, and lithology from the High Plains aquifer. The High Plains aquifer is used to represent a typical sedimentary aquifer overlying a deep CO{sub 2} storage reservoir. Specifically, we address the relationships between CO{sub 2} flux, groundwater flow, detection time and distance. The CO{sub 2} flux ranges from 10{sup 3} to 2 x 10{sup 6} t/yr (0.63 to 1250 t/m{sup 2}/yr) to assess chemical perturbations resulting from relatively small leaks that may compromise long-term storage, water quality, and surface ecology, and larger leaks characteristic of short-term well failure.

  1. Contaminant degradation in physically and chemically heterogeneous aquifers.

    Science.gov (United States)

    Cunningham, Jeffrey A; Fadel, Ziad J

    2007-12-01

    This paper examines the importance of the correlation between hydraulic conductivity (K) and degradation rate constant (k) during the transport of reactive contaminants in heterogeneous aquifers. We simulated reactive transport in an ensemble of two-dimensional heterogeneous aquifers. Two sets of transport simulations were conducted: one in which a perfect positive correlation was assumed between ln(K) and ln(k), and one in which a perfect negative correlation was assumed. We found that the sign of the correlation has important consequences for the contaminant transport. Qualitatively, a negative correlation leads to significantly more pronounced "fingering" of the contaminant plume than does a positive correlation, with potentially important consequences for downgradient receptors. Quantitatively, the expected behavior (as quantified by the contaminant mass remaining in the aquifer) is statistically different between the positive and negative cases: on average, more contaminant mass persists when K and k are negatively correlated. Also, the negative correlation leads to more variability between realizations of the ensemble, whereas a positive correlation induces relatively little variability between realizations. We discuss the implications of these findings for the management of contaminated aquifers. PMID:17854951

  2. Sustainable utilization of the Calera Aquifer, Zacatecas, Mexico

    Science.gov (United States)

    Groundwater extraction from the Calera Aquifer in the State of Zacatecas, Mexico, for irrigation, urban, and industrial uses has increased over recent decades to unsustainable levels. By 2015, irrigated agriculture was projected to use about 84% of total extracted groundwater, urban 10%, and industr...

  3. Water Decisions for Sustainability of the Arbuckle-Simpson Aquifer

    Science.gov (United States)

    Lazrus, H.; Mcpherson, R. A.; Morss, R. E.; PaiMazumder, D.; Silvis, V.; Towler, E.

    2012-12-01

    The Arbuckle-Simpson Aquifer in south-central Oklahoma, situated in the heart of the Chickasaw Nation, is the state's only sole-source groundwater basin and sustains the Blue River, the state's only freeflowing river. The recent comprehensive hydrological studies of the aquifer indicate the need for sustainable management of the amount of water extracted. However, the question of how to deal with that management in the face of increasing drought vulnerability, diverse demands, and climate variability and change remains. Water management carries a further imperative to be inclusive of tribal and non-tribal interests. To address these issues, this interdisciplinary project takes an integrated approach to understanding risk perceptions and water decisions for sustainability of the Arbuckle-Simpson Aquifer. Our interdisciplinary research asks: How do stakeholders in the Arbuckle-Simpson Aquifer perceive drought risks across weather and climate scales, and how do these perceptions guide water management decisions given (i) diverse cultural beliefs, (ii) valued hydrologic services, (iii) past drought experience, and (iv) uncertainties in future projection of precipitation and drought? We will use ethnographic methods to diagnose how cultural values and beliefs inform risk perceptions, and how this in turn guides decision making or ignites conflict across different sectors and stakeholder groups. Further, the characterization of drought risk will be examined in the context of historic meteorological and hydrologic events, as well as climate variability and change. This will identify which risks are prioritized, and under what conditions, in regional decision making or water-related conflicts.

  4. Isotope techniques in the study of the Guarani Aquifer

    International Nuclear Information System (INIS)

    The IAEA, through the Technical Cooperation Project (RLA8036), supports the application of isotope tools as part of a large international project which addresses a number of key questions in hydrolgeology and groundwater uses of the Guarani Aquifer. Groundwater constitutes around 95% of all the planet's fresh and liquid water. It is used by more than two billion people in the world and is considered as the greatest strategic reserve for the next decades. About 26% of the available freshwater in the world is in South America, and more than 50% of its population is supplied by groundwater. Low vulnerability to short climate variations places groundwater in a privileged position when societies' sustainability is evaluated. In spite of this importance, in many of our countries, groundwater resources have not received, nor receive, the attention deserved. During the last decade, the interest in South America about groundwater has grown but the few available management schemes operating in most countries are no longer adequate. As a result of a lack of adequate management schemes, ground pollution and inadequate well-head protection measures, some overexploitation (greater water extraction than the aquifer's potential) and pollution signs have been observed in some aquifers. If actions are not taken to ensure the preservation of these resources and correction measures are not adopted in critical areas, we will place at risk public and private water supply schemes, mainly in urban centres. The actions to be adopted will depend on the existing technical knowledge of the aquifers an on the countries' initiatives

  5. Recovery of energetically overexploited urban aquifers using surface water

    Science.gov (United States)

    García-Gil, Alejandro; Vázquez-Suñé, Enric; Sánchez-Navarro, José Ángel; Mateo Lázaro, Jesús

    2015-12-01

    Shallow aquifers have an important role in reducing greenhouse gases through helping manage the temperature of urban environments. Nevertheless, the uncontrolled rapid use of shallow groundwater resources to heat or cool urban environments can cause thermal pollution that will limit the long term sustainability of the resource. Therefore, there is a need for appropriate mitigation/remediation strategies capable of recovering energetically overexploited aquifers. In this work, a novel remediation strategy based on surface water recharge into aquifers is presented. To evaluate the capabilities of such measures for effective remediation, this strategy is optimized for a management problem raised in the overheated "Urban Alluvial Aquifer of Zaragoza" (Spain). The application of a transient groundwater flow and heat transport model under 512 different mitigation scenarios has enabled to quantify and discuss the magnitude of the remediation effect as a respond to injection rates of surface water, seasonal schedule of the injection and location of injection. The quantification of the relationship between these variables together with the evaluation of the amount of surface water injected per year in each scenario proposed have provided a better understanding of the system processes and an optimal management alternative. This work also makes awareness of the magnitude of the remediation procedure which is in an order of magnitude of tenths of years.

  6. What function tells about structure in heterogeneous aquifers

    Science.gov (United States)

    Lischeid, Gunnar; Steidl, Jörg; Merz, Christoph; Dannowski, Ralf

    2016-04-01

    Hydogeologists and water resources managers are interested in the functional aspects of groundwater systems, that is, the temporal behaviour of groundwater head, patterns of groundwater flow pathways or residence time distribution. These functional aspects highly depend on the structure of the respective aquifer, e.g., on the extent and inclination of confining layers or on the geometry of fissures in hardrock aquifers. Thus a sound knowledge of the prevailing features of the aquifer's structure is a necessary prerequisite for groundwater resources management and application of groundwater models. There is urgent need for efficient ways to extract relevant information from easily available data. When certain structures in the subsurface have a major effect on the functioning of a groundwater system sophisticated analysis of the latter might be used to infer the former in an inverse approach. Then in a next step this information could be used, e.g., for constraining groundwater models. Unless, e.g., for a naïve implementation of geophysical data in groundwater models, the approach outlined here ensures that only structures relevant for hydrogeological functioning are considered, thus minimizing the model structure uncertainty. This approach has been applied in the Quillow catchment in Northeast Germany, a region with a very complex setting of pleistocenic unconsolidated sediments of 200 m thickness, where numerous layers of varying permeability intersect to unknown numbers and extent. Here the key problem is the identification of confining layers that effectively separate different aquifers. Different approaches were combined. Firstly, a principal component analysis was applied to time series of groundwater head from 10 groundwater wells in the study region, allowing to differentiate between different effects on groundwater dynamics. Corresponding to other studies published recently, groundwater head dynamics in the first place depended on the degree of

  7. Hydrochemical processes in a shallow coal seam gas aquifer and its overlying stream–alluvial system: implications for recharge and inter-aquifer connectivity

    International Nuclear Information System (INIS)

    Highlights: • Major ions and isotopes used to study inter-aquifer mixing in a shallow CSG setting. • Considerable heterogeneity in the water composition of the coal-bearing aquifer. • Rapid recharge of the coal-bearing aquifer through highly fractured igneous rocks. • Potential mixing between the coal-bearing aquifer and downstream alluvial aquifer. • Need to consider the seasonal influences on inter-aquifer mixing in CSG settings. - Abstract: In areas of potential coal seam gas (CSG) development, understanding interactions between coal-bearing strata and adjacent aquifers and streams is of highest importance, particularly where CSG formations occur at shallow depth. This study tests a combination of hydrochemical and isotopic tracers to investigate the transient nature of hydrochemical processes, inter-aquifer mixing and recharge in a catchment where the coal-bearing aquifer is in direct contact with the alluvial aquifer and surface drainage network. A strong connection was observed between the main stream and underlying alluvium, marked by a similar evolution from fresh Ca–Mg–HCO3 waters in the headwaters towards brackish Ca–Na–Cl composition near the outlet of the catchment, driven by evaporation and transpiration. In the coal-bearing aquifer, by contrast, considerable site-to-site variations were observed, although waters generally had a Na–HCO3–Cl facies and high residual alkalinity values. Increased salinity was controlled by several coexisting processes, including transpiration by plants, mineral weathering and possibly degradation of coal organic matter. Longer residence times and relatively enriched carbon isotopic signatures of the downstream alluvial waters were suggestive of potential interactions with the shallow coal-bearing aquifer. The examination of temporal variations in deuterium excess enabled detection of rapid recharge of the coal-bearing aquifer through highly fractured igneous rocks, particularly at the catchment

  8. Water balance of global aquifers revealed by groundwater footprint.

    Science.gov (United States)

    Gleeson, Tom; Wada, Yoshihide; Bierkens, Marc F P; van Beek, Ludovicus P H

    2012-08-01

    Groundwater is a life-sustaining resource that supplies water to billions of people, plays a central part in irrigated agriculture and influences the health of many ecosystems. Most assessments of global water resources have focused on surface water, but unsustainable depletion of groundwater has recently been documented on both regional and global scales. It remains unclear how the rate of global groundwater depletion compares to the rate of natural renewal and the supply needed to support ecosystems. Here we define the groundwater footprint (the area required to sustain groundwater use and groundwater-dependent ecosystem services) and show that humans are overexploiting groundwater in many large aquifers that are critical to agriculture, especially in Asia and North America. We estimate that the size of the global groundwater footprint is currently about 3.5 times the actual area of aquifers and that about 1.7 billion people live in areas where groundwater resources and/or groundwater-dependent ecosystems are under threat. That said, 80 per cent of aquifers have a groundwater footprint that is less than their area, meaning that the net global value is driven by a few heavily overexploited aquifers. The groundwater footprint is the first tool suitable for consistently evaluating the use, renewal and ecosystem requirements of groundwater at an aquifer scale. It can be combined with the water footprint and virtual water calculations, and be used to assess the potential for increasing agricultural yields with renewable groundwaterref. The method could be modified to evaluate other resources with renewal rates that are slow and spatially heterogeneous, such as fisheries, forestry or soil.

  9. AUTOMATED WATER LEVEL MEASUREMENTS IN SMALL-DIAMETER AQUIFER TUBES

    Energy Technology Data Exchange (ETDEWEB)

    PETERSEN SW; EDRINGTON RS; MAHOOD RO; VANMIDDLESWORTH PE

    2011-01-14

    Groundwater contaminated with hexavalent chromium, strontium-90, and uranium discharges into the Columbia River along approximately 16 km (10 mi) of the shoreline. Various treatment systems have and will continue to be implemented to eliminate the impact of Hanford Site contamination to the river. To optimize the various remediation strategies, it is important to understand interactions between groundwater and the surface water of the Columbia River. An automated system to record water levels in aquifer sampling tubes installed in the hyporheic zone was designed and tested to (1) gain a more complete understanding of groundwater/river water interactions based on gaining and losing conditions ofthe Columbia River, (2) record and interpret data for consistent and defensible groundwater/surface water conceptual models that may be used to better predict subsurface contaminant fate and transport, and (3) evaluate the hydrodynamic influence of extraction wells in an expanded pump-and-treat system to optimize the treatment system. A system to measure water levels in small-diameter aquifer tubes was designed and tested in the laboratory and field. The system was configured to allow manual measurements to periodically calibrate the instrument and to permit aquifer tube sampling without removing the transducer tube. Manual measurements were collected with an e-tape designed and fabricated especially for this test. Results indicate that the transducer system accurately records groundwater levels in aquifer tubes. These data are being used to refine the conceptual and numeric models to better understand interactions in the hyporheic zone of the Columbia River and the adjacent river water and groundwater, and changes in hydrochemistry relative to groundwater flux as river water recharges the aquifer and then drains back out in response to changes in the river level.

  10. In situ arsenic removal in an alkaline clastic aquifer

    Science.gov (United States)

    Welch, A.H.; Stollenwerk, K.G.; Paul, A.P.; Maurer, D.K.; Halford, K.J.

    2008-01-01

    In situ removal of As from ground water used for water supply has been accomplished elsewhere in circum-neutral ground water containing high dissolved Fe(II) concentrations. The objective of this study was to evaluate in situ As ground-water treatment approaches in alkaline ground-water (pH > 8) that contains low dissolved Fe (aquifers studied are similar except for the inorganic As species. Although total inorganic As concentrations were similar, one aquifer has dominantly aqueous As(III) and the other has mostly As(V). Dissolved O2, Fe(II), and HCl were added to water and injected into the two aquifers to form Fe-oxide and lower the pH to remove As. Cycles of injection and withdrawal involved varying Fe(II) concentrations in the injectate. The As concentrations in water withdrawn from the two aquifers were as low as 1 and 6 ??g/L, with greater As removal from the aquifer containing As(V). However, Fe and Mn concentrations increased to levels greater than US drinking water standards during some of the withdrawal periods. A balance between As removal and maintenance of low Fe and Mn concentrations may be a design consideration if this approach is used for public-supply systems. The ability to lower As concentrations in situ in high-pH ground water should have broad applicability because similar high-As ground water is present in many parts of the world. ?? 2008.

  11. The source of naturally occurring arsenic in a coastal sand aquifer of eastern Australia.

    Science.gov (United States)

    O'Shea, Bethany; Jankowski, Jerzy; Sammut, Jesmond

    2007-07-01

    The discovery of dissolved arsenic in a coastal aquifer used extensively for human consumption has led to widespread concern for its potential occurrence in other sandy coastal environments in eastern Australia. The development of an aquifer specific geomorphic model (herein) suggests that arsenic is regionally derived from erosion of arsenic-rich stibnite (Sb(2)S(3)) mineralisation present in the hinterland. Fluvial processes have transported the eroded material over time to deposit an aquifer lithology elevated in arsenic. Minor arsenic contribution to groundwater is derived from mineralised bedrock below the unconsolidated aquifer. An association with arsenic and pyrite has been observed in the aquifer in small discrete arsenian pyrite clusters rather than actual acid sulfate soil horizons. This association is likely to influence arsenic distribution in the aquifer, but is not the dominant control on arsenic occurrence. Arsenic association with marine clays is considered a function of their increased adsorptive capacity for arsenic and not solely on the influence of sea level inundation of the aquifer sediments during the Quaternary Period. These findings have implications for, but are not limited to, coastal aquifers. Rather, any aquifer containing sediments derived from mineralised provenances may be at risk of natural arsenic contamination. Groundwater resource surveys should thus incorporate a review of the aquifer source provenance when assessing the likely risk of natural arsenic occurrence in an aquifer.

  12. Factors affecting public-supply well vulnerability in two karst aquifers

    Science.gov (United States)

    Musgrove, MaryLynn; Katz, Brian G.; Fahlquist, Lynne S.; Crandall, Christy A.; Lindgren, Richard J.

    2014-01-01

    Karst aquifers occur in a range of climatic and geologic settings. Nonetheless, they are commonly characterized by their vulnerability to water-quality impairment. Two karst aquifers, the Edwards aquifer in south-central Texas and the Upper Floridan aquifer in western Florida, were investigated to assess factors that control the movement of contaminants to public-supply wells (PSWs). The geochemistry of samples from a selected PSW or wellfield in each aquifer was compared with that from nearby monitoring wells and regional PSWs. Geochemistry results were integrated with age tracers, flow modeling, and depth-dependent data to refine aquifer conceptual models and to identify factors that affect contaminant movement to PSWs. The oxic Edwards aquifer is vertically well mixed at the selected PSW/wellfield, although regionally the aquifer is geochemically variable downdip. The mostly anoxic Upper Floridan aquifer is affected by denitrification and also is geochemically variable with depth. In spite of considerable differences in geology and hydrogeology, the two aquifers are similarly vulnerable to anthropogenic contamination. Vulnerability in studied PSWs in both aquifers is strongly influenced by rapid karst flowpaths and the dominance of young (karst groundwater management.

  13. Ground-water hydraulics of the deep-basin brine aquifer, Palo Duro Basin, Texas panhandle

    International Nuclear Information System (INIS)

    The Deep-Basin Brine aquifer of the Palo Duro Basin (Texas Panhandle) underlies thick Permian bedded evaporites that are being evaluated as a potential high-level nuclear waste isolation repository. Potentiometric surface maps of 5 units of the Deep-Basin Brine aquifer were drawn using drill-stem test (DST) pressure data, which were analyzed by a geostatistical technique (kriging) to smooth the large variation in the data. The potentiometric surface maps indicate that the Deep-Basin Brine aquifer could be conceptually modeled as 5 aquifer units; a Lower Permian (Wolfcamp) aquifer, upper and lower Pennsylvanian aquifers, a pre-Pennsylvanian aquifer, and a Pennsylvanian to Wolfcampian granite-wash aquifer. The hydraulic head maps indicate that ground-water flow in each of the units is west to east with a minor northerly component near the Amarillo Uplift, the northern structural boundary of the basin. The Wolfcamp potentiometric surface indicates the strongest component of northerly flow. Inferred flow direction in Pennsylvanian aquifers is easterly, and in the pre-Pennsylvanian aquifer near its pinch-out in the basin center, flow is inferred to be to the north. In the granite-wash aquifer the inferred flow direction is east across the northern edge of the basin and southeast along the Amarillo Uplift

  14. Karst connections between unconfined aquifers and the Upper Floridan aquifer in south Georgia: geophysical evidence and hydrogeological models

    Science.gov (United States)

    Thieme, D. M.; Denizman, C.

    2011-12-01

    Buried karst features in sedimentary rocks of the south Georgia Coastal Plain present a challenge for hydrogeological models of recharge and confined flow within the underlying Upper Floridan aquifer. The Withlacoochee River, the trunk stream for the area, frequently disappears into subsurface caverns as it makes its way south to join the Suwannee River in northern Florida. The Withlacoochee also receives inputs from small ponds and bays which in turn receive spring and seep groundwater inputs. We have mapped karst topography at the "top of rock" using ground-penetrating radar (GPR). Up to seven meters of relief is indicated for the paleotopography on Miocene to Pliocene rocks, contrasting with the more subdued relief of the modern landscape. Current stratigraphic and hydrogeological reconstructions do not incorporate this amount of relief or lateral variation in the confining beds. One "pipe" which is approximately four meters in diameter is being mapped in detail. We have field evidence at this location for rapid movement of surficial pond and river water with a meteoric signature through several separate strata of sedimentary rock into an aquifer in the Hawthorn formation. We use our geophysical and hydrological field evidence to constrain quantitative hydrogeological models for the flow rates into and out of both this upper aquifer and the underlying Upper Floridan aquifer, which is generally considered to be confined by the clays of the Hawthorn.

  15. Potentiometric-surface altitude of the confined aquifer, Wood River Valley aquifer system, south-central Idaho, October 2012.

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Water levels in 93 wells completed in the Wood River Valley aquifer system were measured during October 22–24, 2012; these wells are part of a network established...

  16. Water-table altitude of the unconfined aquifer, Wood River Valley aquifer system, south-central Idaho, October 2012.

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Water levels in 93 wells completed in the Wood River Valley aquifer system were measured during October 22–24, 2012; these wells are part of a network established...

  17. Geospatial compilation of historical water-level changes in the Chicot and Evangeline aquifers 1977-2013 and Jasper aquifer 2000-13, Gulf Coast aquifer system, Houston-Galveston region, Texas

    Science.gov (United States)

    Johnson, Michaela R.; Linard, Joshua I.

    2014-01-01

    The U.S. Geological Survey (USGS) in cooperation with the Harris-Galveston Subsidence District, City of Houston, Fort Bend Subsidence District, Lone Star Groundwater Conservation District, and Brazoria County Groundwater Conservation District has produced an annual series of reports that depict water-level changes in the Chicot, Evangeline, and Jasper aquifers of the Gulf Coast aquifer system in the Houston-Galveston region, Texas, from 1977 to 2013. Changes are determined from water-level measurements between December and March of each year from groundwater wells screened in one of the three aquifers. Existing published maps and unpublished geographic information system (GIS) datasets were compiled into a comprehensive geodatabase of all water-level-change maps produced as part of this multiagency effort. Annual water-level-change maps were georeferenced and digitized where existing GIS data were unavailable (1979–99). Existing GIS data available for 2000–13 were included in the geodatabase. The compilation contains 121 datasets showing water-level changes for each primary aquifer of the Gulf Coast aquifer system: 56 for the Chicot aquifer (1977; 1979–2013 and 1990; 1993–2013), 56 for the Evangeline aquifer (1977; 1979–2013 and 1990; 1993–2013), and 9 for the Jasper aquifer (2000; 2005–13).

  18. Investigating groundwater flow between Edwards and Trinity aquifers in central Texas.

    Science.gov (United States)

    Wong, C I; Kromann, J S; Hunt, B B; Smith, B A; Banner, J L

    2014-01-01

    Understanding the nature of communication between aquifers can be challenging when using traditional physical and geochemical groundwater sampling approaches. This study uses two multiport wells completed within Edwards and Trinity aquifers in central Texas to determine the degree of groundwater inter-flow between adjacent aquifers. Potentiometric surfaces, hydraulic conductivities, and groundwater major ion concentrations and Sr isotope values were measured from multiple zones within three hydrostratigraphic units (Edwards and Upper and Middle Trinity aquifers). Physical and geochemical data from the multiport wells were combined with historical measurements of groundwater levels and geochemical compositions from the region to characterize groundwater flow and identify controls on the geochemical compositions of the Edwards and Trinity aquifers. Our results suggest that vertical groundwater flow between Edwards and Middle Trinity aquifers is likely limited by low permeability, evaporite-rich units within the Upper and Middle Trinity. Potentiometric surface levels in both aquifers vary with changes in wet vs. dry conditions, indicating that recharge to both aquifers occurs through distinct recharge areas. Geochemical compositions in the Edwards, Upper, and Middle Trinity aquifers are distinct and likely reflect groundwater interaction with different lithologies (e.g., carbonates, evaporites, and siliceous sediments) as opposed to mixing of groundwater between the aquifers. These results have implications for the management of these aquifers as they indicate that, under current conditions, pumping of either aquifer will likely not induce vertical cross-formational flow between the aquifers. Inter-flow between the Trinity and the Edwards aquifers, however, should be reevaluated as pumping patterns and hydrogeologic conditions change.

  19. Estimating hydraulic properties of volcanic aquifers using constant-rate and variable-rate aquifer tests

    Science.gov (United States)

    Rotzoll, K.; El-Kadi, A. I.; Gingerich, S.B.

    2007-01-01

    In recent years the ground-water demand of the population of the island of Maui, Hawaii, has significantly increased. To ensure prudent management of the ground-water resources, an improved understanding of ground-water flow systems is needed. At present, large-scale estimations of aquifer properties are lacking for Maui. Seven analytical methods using constant-rate and variable-rate withdrawals for single wells provide an estimate of hydraulic conductivity and transmissivity for 103 wells in central Maui. Methods based on constant-rate tests, although not widely used on Maui, offer reasonable estimates. Step-drawdown tests, which are more abundantly used than other tests, provide similar estimates as constant-rate tests. A numerical model validates the suitability of analytical solutions for step-drawdown tests and additionally provides an estimate of storage parameters. The results show that hydraulic conductivity is log-normally distributed and that for dike-free volcanic rocks it ranges over several orders of magnitude from 1 to 2,500 m/d. The arithmetic mean, geometric mean, and median values of hydraulic conductivity are respectively 520, 280, and 370 m/d for basalt and 80, 50, and 30 m/d for sediment. A geostatistical approach using ordinary kriging yields a prediction of hydraulic conductivity on a larger scale. Overall, the results are in agreement with values published for other Hawaiian islands. ?? 2007 American Water Resources Association.

  20. Aquifer vulnerability to pesticide pollution - Combining soil, land-use and aquifer properties with molecular descriptors

    Science.gov (United States)

    Worrall, F.; Kolpin, D.W.

    2004-01-01

    This study uses an extensive survey of herbicides in groundwater across the midwest United States to predict occurrences of a range of compounds across the region from a combination of their molecular properties and the properties of the catchment of a borehole. The study covers 100 boreholes and eight pesticides. For each of the boreholes its catchment the soil, land-use and aquifer properties were characterized. Discriminating boreholes where pollution occurred from those where no pollution occurred gave a model that was 74% correct with organic carbon content, percentage sand content and depth to the water table being significant properties of the borehole catchment. Molecular topological descriptors as well as Koc, solubility and half-life were used to characterize each compound included in the study. Inclusion of molecular properties makes it possible to discriminate between occurrence and non-occurrence of each compound in each well. The best-fit model combines: organic carbon content, percentage sand content and depth to the water table with molecular descriptors representing molecular size, molecular branching and functional group composition of the herbicides.

  1. Reconstruction of the Friuli Venezia Giulia Plain aquifers

    Science.gov (United States)

    Calligaris, Chiara; Cimolino, Aurelie; Cucchi, Franco; Deana, Alberto; Treu, Francesco; Zini, Luca

    2010-05-01

    The constantly increasing of water demand for human consumptions has necessitated a reconstruction of the hydrogeologic characteristics and properties as well isotopic features of the aquifers of the Friuli Venezia Giulia Plain (FP). The DiSGAM and DICA have been engaged by the Hydraulic Survey of the FVG Region in order to coordinate an integrated study finalized to the FP confined and unconfined aquifer geometries reconstruction and to provide guide-lines for water rational exploitation (Agreement D.G.R. n. 1827 dd. 27.07.2007). The Friuli Venezia Giulia Plain, located in the northeastern sector of Italy, hosts well developed Plio-Quaternary unconfined and confined alluvial aquifers. The main surface drainage of the Plain is the Tagliamento River. The regional hydrogeological situation is characterized in the north by an extensive alluvial unconfined aquifer mostly contained in carbonate gravels. This area extends from the Pre-Alps to the resurgence belt. The resurgence belt is 2 to 8 km wide and 80 kilometres long. In this area the water table intersects the topographic surface forming numerous plain springs and rivers. The resurgence belt sets a geohydrological boundary between the Upper and Lower Friulian Plain. In this strip the unconfined aquifer changes into a multi-layered confined that reach a thickness of up to 500 m with a progressive increase in a westward direction towards the Adriatic Sea. In order to define underground aquifer relations and patterns, more than 1800 stratigraphic columns have been collected from different public departments water well database. Well logs have been georeferred, missing elevations calculated by regional DTM, possible correspondences controlled and datasets updated. In order to better correlate spatial data, an unique implemented lithostratigraphy legend has been created from present different ones; it is composed of: Lithological Entries (relating lithology and granulometric features; permeability linked different

  2. Aquifer/aquitard interfaces: mixing zones that enhance biogeochemical reactions

    Science.gov (United States)

    McMahon, P. B.

    2001-01-01

    Several important biogeochemical reactions are known to occur near the interface between aquifer and aquitard sediments. These reactions include O2 reduction; denitrification; and Fe3+, SO42-, and CO2 (methanogenesis) reduction. In some settings, these reactions occur on the aquitard side of the interface as electron acceptors move from the aquifer into the electron-donor-enriched aquitard. In other settings, these reactions occur on the aquifer side of the interface as electron donors move from the aquitard into the electron-acceptor-enriched, or microorganism-enriched, aquifer. Thus, the aquifer/aquitard interface represents a mixing zone capable of supporting greater microbial activity than either hydrogeologic unit alone. The extent to which biogeochemical reactions proceed in the mixing zone and the width of the mixing zone depend on several factors, including the abundance and solubility of electron acceptors and donors on either side of the interface and the rate at which electron acceptors and donors react and move across the interface. Biogeochemical reactions near the aquifer/aquitard interface can have a substantial influence on the chemistry of water in aquifers and on the chemistry of sediments near the interface. Résumé. Il se produit au voisinage de l'interface entre les aquifères et les imperméables plusieurs réactions biogéochimiques importantes. Il s'agit des réactions de réduction de l'oxygène, de la dénitrification et de la réduction de Fe3+, SO42- et CO2 (méthanogenèse). Dans certaines situations, ces réactions se produisent du côté imperméable de l'interface, avec des accepteurs d'électrons qui vont de l'aquifère vers l'imperméable riche en donneurs d'électrons. Dans d'autres situations, ces réactions se produisent du côté aquifère de l'interface, avec des donneurs d'électrons qui se déplacent de l'imperméable vers l'aquifère riche en accepteurs d'électrons ou en microorganismes. Ainsi, l'interface aquif

  3. Arsenic Attenuation By Oxidized Aquifer Sediments in Bangladesh

    Energy Technology Data Exchange (ETDEWEB)

    Stollenwerk, K.G.; Breit, G.N.; Welch, A.H.; Yount, J.C.; Whitney, J.W.; Foster, A.L.; Uddin, M.N.; Majumder, R.K.; Ahmed, N.; /Geological Survey, Denver /Geological

    2007-07-13

    Recognition of arsenic (As) contamination of shallow fluvio-deltaic aquifers in the Bengal Basin has resulted in increasing exploitation of groundwater from deeper aquifers that generally contain low concentrations of dissolved As. Pumping-induced infiltration of high-As groundwater could eventually cause As concentrations in these aquifers to increase. This study investigates the adsorption capacity for As of sediment from a low-As aquifer near Dhaka, Bangladesh. A shallow, chemically-reducing aquifer at this site extends to a depth of 50 m and has maximum As concentrations in groundwater of 900 {micro}g/L. At depths greater than 50 m, geochemical conditions are more oxidizing and groundwater has < 5 {micro}g/L As. There is no thick layer of clay at this site to inhibit vertical transport of groundwater. Arsenite [As(III)] is the dominant oxidation state in contaminated groundwater; however, data from laboratory batch experiments show that As(III) is oxidized to arsenate [As(V)] by manganese (Mn) minerals that are present in the oxidized sediment. Thus, the long-term viability of the deeper aquifers as a source of water supply is likely to depend on As(V) adsorption. The adsorption capacity of these sediments is a function of the oxidation state of As and the concentration of other solutes that compete for adsorption sites. Arsenite that was not oxidized did adsorb, but to a much lesser extent than As(V). Phosphate (P) caused a substantial decrease in As(V) adsorption. Increasing pH and concentrations of silica (Si) had lesser effects on As(V) adsorption. The effect of bicarbonate (HCO{sub 3}) on As(V) adsorption was negligible. Equilibrium constants for adsorption of As(V), As(III), P, Si, HCO3, and H were determined from the experimental data and a quantitative model developed. Oxidation of As(III) was modeled with a first-order rate constant. This model was used to successfully simulate As(V) adsorption in the presence of multiple competing solutes. Results

  4. Arsenic attenuation by oxidized aquifer sediments in Bangladesh

    Science.gov (United States)

    Stollenwerk, K.G.; Breit, G.N.; Welch, A.H.; Yount, J.C.; Whitney, J.W.; Foster, A.L.; Uddin, M.N.; Majumder, R.K.; Ahmed, N.

    2007-01-01

    Recognition of arsenic (As) contamination of shallow fluvio-deltaic aquifers in the Bengal Basin has resulted in increasing exploitation of groundwater from deeper aquifers that generally contain low concentrations of dissolved As. Pumping-induced infiltration of high-As groundwater could eventually cause As concentrations in these aquifers to increase. This study investigates the adsorption capacity for As of sediment from a low-As aquifer near Dhaka, Bangladesh. A shallow, chemically-reducing aquifer at this site extends to a depth of 50??m and has maximum As concentrations in groundwater of 900????g/L. At depths greater than 50??m, geochemical conditions are more oxidizing and groundwater has < 5????g/L As. There is no thick layer of clay at this site to inhibit vertical transport of groundwater. Arsenite [As(III)] is the dominant oxidation state in contaminated groundwater; however, data from laboratory batch experiments show that As(III) is oxidized to arsenate [As(V)] by manganese (Mn) minerals that are present in the oxidized sediment. Thus, the long-term viability of the deeper aquifers as a source of water supply is likely to depend on As(V) adsorption. The adsorption capacity of these sediments is a function of the oxidation state of As and the concentration of other solutes that compete for adsorption sites. Arsenite that was not oxidized did adsorb, but to a much lesser extent than As(V). Phosphate (P) caused a substantial decrease in As(V) adsorption. Increasing pH and concentrations of silica (Si) had lesser effects on As(V) adsorption. The effect of bicarbonate (HCO3) on As(V) adsorption was negligible. Equilibrium constants for adsorption of As(V), As(III), P, Si, HCO3, and H were determined from the experimental data and a quantitative model developed. Oxidation of As(III) was modeled with a first-order rate constant. This model was used to successfully simulate As(V) adsorption in the presence of multiple competing solutes. Results from these

  5. Modeling of groundwater flow for Mujib aquifer, Jordan

    Indian Academy of Sciences (India)

    Fayez Abdulla; Tamer Al-Assa’d

    2006-06-01

    Jordan is an arid country with very limited water resources.Groundwater is the main source for its water supply.Mujib aquifer is located in the central part of Jordan and is a major source of drinking water for Amman,Madaba and Karak cities.High abstraction rates from Mujib aquifer during the previous years lead to a major decline in water levels and deterioration in groundwater quality. Therefore,proper groundwater management of Mujib aquifer is necessary;and groundwater flow modeling is essential for proper management.For this purpose,Mod flow was used to build a groundwater flow model to simulate the behavior of the flow system under different stresses.The model was calibrated for steady state condition by matching observed and simulated initial head counter lines.Drawdown data for the period 1985-1995 were used to calibrate the transient model by matching simulated drawdown with the observed one.Then,the transient model was validated by using drawdown data for the period 1996-2002.The results of the calibrated model showed that the horizontal hydraulic conductivity of the B2/A7 aquifer ranges between 0.001 and 40 m/d. Calibrated speci fic yield ranges from 0.0001 to 0.15.The water balance for the steady state condition of Mujib aquifer indicated that the total annual direct recharge is 20.4 × 106 m3, the total annual in flow is 13.0 × 106 m3, springs discharge is 15.3 × 106 m3, and total annual out flow is 18.7 × 106 m3. Different scenarios were considered to predict aquifer system response under different conditions. The results of the sensitivity analysis show that the model is highly sensitive to horizontal hydraulic conductivity and anisotropy and with lower level to the recharge rates.Also the model is sensitive to specific yield.

  6. Virtual Drawdown Tests of Groundwater Aquifers from Insar Remote Sensing

    Science.gov (United States)

    Zebker, H. A.; Chen, J.; Smith, R.

    2015-12-01

    Groundwater management depends on the type and quality of field data available describing a given aquifer system. Our increasing reliance on groundwater, especially as traditional surface supplies continue to be overexploited due to rising population and standard of living, requires that we better understand the state of our subsurface supplies. Groundwater aquifers, and the water flow models that relate aquifer parameters to management strategies, are typically characterized in terms of how much water is available at any point in the basin (storativity), and how easily water can flow from one point to another (transmissivity). Often these parameters are estimated by field drawdown tests, in which a known quantity of water is withdrawn from the aquifer, and the resulting spatial and temporal distribution of hydraulic head analyzed. Pumping tests can be expensive and time consuming, so that for most aquifer systems very few drawdown test data sets exist. Here we show that estimates for storativity and hydraulic conductance can be derived from time series InSAR observations coupled with well head measurements. While this requires the presence of monitoring wells in the basin, monitor-only wells are often fairly plentiful. Comparison of hydraulic head and InSAR deformation data at a monitoring well yields the ratio of head to subsidence and any time delay between the two, from which we solve for the needed conductivity and storativity. We present examples of these parameters associated with groundwater systems in the San Luis Valley, CO, and the Central Valley area of California, as observed by several spaceborne radar systems and validated by comparison with field data. The fundamental relation between pressure and stress resulting in changes in hydraulic head yields a simple linear relationship between deformation Δb, hydraulic head Δh, and skeletal storage coefficient: Sk = Δb / Δh, so that measuring deformation everywhere above an aquifer over time yields

  7. Hydrogeology, ground-water movement, and subsurface storage in the Floridan aquifer system in southern Florida

    Science.gov (United States)

    Meyer, Frederick W.

    1989-01-01

    The Floridan aquifer system of southern Florida is composed chiefly of carbonate rocks that range in age from early Miocene to Paleocene. The top of the aquifer system in southern Florida generally is at depths ranging from 500 to 1,000 feet, and the average thickness is about 3,000 feet. It is divided into three general hydrogeologic units: (1) the Upper Floridan aquifer, (2) the middle confining unit, and (3) the Lower Floridan aquifer. The Upper Floridan aquifer contains brackish ground water, and the Lower Floridan aquifer contains salty ground water that compares chemically to modern seawater. Zones of high permeability are present in the Upper and Lower Floridan aquifers. A thick, cavernous dolostone in the Lower Floridan aquifer, called the Boulder Zone, is one of the most permeable carbonate units in the world (transmissivity of about 2.5 x 107 feet squared per day). Ground-water movement in the Upper Floridan aquifer is generally southward from the area of highest head in central Florida, eastward to the Straits of Florida, and westward to the Gulf of Mexico. Distributions of natural isotopes of carbon and uranium generally confirm hydraulic gradients in the Lower Floridan aquifer. Groundwater movement in the Lower Floridan aquifer is inland from the Straits of Florida. The concentration gradients of the carbon and uranium isotopes indicate that the source of cold saltwater in the Lower Floridan aquifer is seawater that has entered through the karat features on the submarine Miami Terrace near Fort Lauderdale. The relative ages of the saltwater suggest that the rate of inland movement is related in part to rising sea level during the Holocene transgression. Isotope, temperature, and salinity anomalies in waters from the Upper Floridan aquifer of southern Florida suggest upwelling of saltwater from the Lower Floridan aquifer. The results of the study support the hypothesis of circulating relatively modern seawater and cast doubt on the theory that the

  8. Regeneration of a confined aquifer after redevelopment and decommission of artesian wells, example from Grafendorf aquifer (Styria, Austria)

    Science.gov (United States)

    Mehmedovski, Nudzejma; Winkler, Gerfried

    2016-04-01

    Water is essential for life and it is therefore necessary to protect drinking water sustainably. Compared to shallow groundwater, deeper groundwater is especially important due to its characteristic tendency to remain extensively unaffected by environmental impacts. Thus, the uncontrolled waste of this valuable resource has to be avoided. A lot of artesian wells have been established in Grafendorf bei Hartberg (Styria, Austria). Almost all wells were not state-of-the art. As a result the different aquifer horizons began to intermix. Additionally some of the artesian wells had a permanent free overflow and the water was not even used. Consequently, since 1950, where the mean discharge of 37 wells was 0,334 l/s per well, the discharge has decreased to 0,090 l/s until 2013, which means a decline of about 75 %. As a reaction to these declines a decommissioning campaign was conducted where 69 artesian wells have been closed by injecting a cement-bentonite suspension (ratio 3:1). The Grafendorf aquifer is situated in the Styrian Basin and consists of 5 separated artesian horizons in Neogene sediments. These artesian horizons range from 42 m (1st horizon) to 176 m (5th horizon) and mostly consist of sand, partly of fine/medium/coarse gravel and partially with minor clay content. In order to analyse the reaction of the Grafendorf aquifer to these redevelopments, 5 monitoring wells could be used for the analysis. Some monitoring wells include different aquifer horizons and hydraulically short cut them. Thus, in this work the analysis focus on the general trend of the whole aquifer system neglecting the individual interactions between the different aquifers. In a first investigation step the hydraulic properties of the aquifer system has been determined using pumping tests which were analysed with different analytical solutions with the software AQTESOLV. Overall the pumping test solutions hardly differ in the transmissivity and hydraulic conductivity. On the contrary the

  9. Movement of coliform bacteria and nutrients in ground water flowing through basalt and sand aquifers.

    Science.gov (United States)

    Entry, J A; Farmer, N

    2001-01-01

    Large-scale deposition of animal manure can result in contamination of surface and ground water and in potential transfer of disease-causing enteric bacteria to animals or humans. We measured total coliform bacteria (TC), fecal coliform bacteria (FC), NO3, NH4, total P, and PO4 in ground water flowing from basalt and sand aquifers, in wells into basalt and sand aquifers, in irrigation water, and in river water. Samples were collected monthly for 1 yr. Total coliform and FC numbers were always higher in irrigation water than in ground water, indicating that soil and sediment filtered most of these bacteria before they entered the aquifers. Total coliform and FC numbers in ground water were generally higher in the faster flowing basalt aquifer than in the sand aquifer, indicating that the slower flow and finer grain size may filter more TC and FC bacteria from water. At least one coliform bacterium/100 mL of water was found in ground water from both basalt and sand aquifers, indicating that ground water pumped from these aquifers is not necessarily safe for human consumption according to the American Public Health Association and the USEPA. The NO3 concentrations were usually higher in water flowing from the sand aquifer than in water flowing from the basalt aquifer or in perched water tables in the basalt aquifer. The PO4 concentrations were usually higher in water flowing from the basalt aquifer than in water flowing from the sand aquifer. The main concern is fecal contamination of these aquifers and health consequences that may arise from human consumption.

  10. Semi-analytical solution of groundwater flow in a leaky aquifer system subject to bending effect

    Science.gov (United States)

    Yu, Chia-Chi; Yang, Shaw-Yang; Yeh, Hund-Der

    2013-04-01

    SummaryThe bending of aquitard like a plate due to aquifer pumping and compression is often encountered in many practical problems of subsurface flow. This reaction will have large influence on the release of the volume of water from the aquifer, which is essential for the planning and management of groundwater resources in aquifers. However, the groundwater flow induced by pumping in a leaky aquifer system is often assumed that the total stress of aquifer maintains constant all the time and the mechanical behavior of the aquitard formation is negligible. Therefore, this paper devotes to the investigation of the effect of aquitard bending on the drawdown distribution in a leaky aquifer system, which is obviously of interest in groundwater hydrology. Based on the work of Wang et al. (2004) this study develops a mathematical model for investigating the impacts of aquitard bending and leakage rate on the drawdown of the confined aquifer due to a constant-rate pumping in the leaky aquifer system. This model contains three equations; two flow equations delineate the transient drawdown distributions in the aquitard and the confined aquifer, while the other describes the vertical displacement in response to the aquitard bending. For the case of no aquitard bending, this new solution can reduce to the Hantush Laplace-domain solution (Hantush, 1960). On the other hand, this solution without the leakage effect can reduce to the time domain solution of Wang et al. (2004). The results show that the aquifer drawdown is influenced by the bending effect at early time and by the leakage effect at late time. The results of sensitivity analysis indicate that the aquifer compaction is sensitive only at early time, causing less amount of water released from the pumped aquifer than that predicted by the traditional groundwater theory. The dimensionless drawdown is rather sensitive to aquitard's hydraulic conductivity at late time. Additionally, both the hydraulic conductivity and

  11. Perched aquifers - their potential impact on contaminant transport in the southern High Plains, Texas

    International Nuclear Information System (INIS)

    Understanding the hydrogeology and hydrochemistry of perched aquifers at potential and known contaminated waste sites has become increasingly important because of the impact these aquifers may have on contaminant transport independent of regional aquifer processes. Investigations of a perched aquifer above the Ogallala aquifer are being conducted in the region of the U.S. Department of Energy's Pantex Plant, a proposed Superfund site, located approximately 20 mi northeast of Amarillo, Texas. Since the early 1950s, a small playa basin located on the Pantex Plant has been used as a waste-water discharge pond with daily discharge rates ranging from 400,000 to 1 million gal. The focus of this investigation is an unconfined, perched aquifer that overlies a thick silty clay sequence within the upper, mostly unsaturated part of the Ogallala Formation (Neogene). In the area of the Pantex Plant, measured depths to the perched aquifer range from 200 to 300 ft below land surface, whereas depth to the regional Ogallala aquifer ranges from 375 to 500 ft. The potentiometric surface of the perched aquifer typically represents groundwater mounds proximal to the playas and thins into trough in the interplaya areas. Hydrologic gradients of the primary mound under investigation are relatively high, ranging from 28 to 45 ft/mi. Calculated transmissivities have a geometric mean of 54 ft2/day, with saturated thicknesses ranging from 4 to 1000 ft. Modeling of the perched aquifer was designed to determine how much, if any, discharge to the small playa basin has enhanced recharge to the perched aquifers and increased the vertical and lateral extent of the perched aquifer. Preliminary results indicate that measurements of vertical conductance through the perching silty-clay sequence and recharge rates through playas are critical for calibrating the model. Accurate delineation of rates and flow directions in the perched aquifer is critical to any successful remediation effort

  12. Aquifer recharge estimation at the Mesilla Bolson and Guaymas aquifer systems, Mexico

    International Nuclear Information System (INIS)

    Three unsaturated profiles were obtained from Mesilla Bolson and Guaymas aquifer systems, northern Mexico. About 500 mL of undisturbed soil from depths between 1 m and 58 m below the surface were obtained every meter by dry percussion from a borehole located near Cd Juarez, Chihuahua state. The other two boreholes were located in the southwestern portion of Sonora state; about 500 mL of undisturbed soil from depths 0-5.50 and 0- 8.50 m were obtained every 0.25 m by dry drilling at Narciso Mendoza and Guaymas sites, respectively. Samples were contained in sealed glass jars and analyzed for moisture content, chloride, deuterium and nitrate (NO3-N). The interstitial water was extracted by elution; chloride and nitrate were determined by automated colorimetry while deuterium by direct reduction. Considering an average precipitation at Mesilla Bolson area of 230 mm/year, a chloride rain content of 1 mg/L and a mean Cl content on the unsaturated profile of 977 mg/L below the zero flux plane, we estimated by the Cl mass balance approach a net palaeorecharge in the area of about 0.24 mm/year with a probable time scale profile of 11,000 years. For the Guaymas area the net recharge is in the range 0.11-0.16 mm/year, assuming an average rainfall of 320 mm/year, Cl rainfall content of 3.4 mg/L and mean Cl concentrations on the profiles of 6,939 and 9,470 mg/L below the zero flux plane, respectively. (author)

  13. Biological transformation of phenols in a sandstone aquifer

    DEFF Research Database (Denmark)

    Broholm, M.; Arvin, E.

    1997-01-01

    Ammonia liquor with very high concentrations of phenols is known to have leaked into the subsurface at a former coal carbonization plant in the UK. High concentrations of ammonium has been encountered in the groundwater reservoir at the site. In spite of this no significant concentrations...... of phenols are found in the groundwater. In this study the potential for transformation of the phenols in the sandstone aquifer at the site under aerobic, nitrate enriched and ''unaltered'' (limited nitrate available, ironoxides and sulphate available) is investigated in laboratory microcosms. Preliminary...... results reveal complete transformation of phenol, cresols and 3,4-xylenol under all 3 conditions and of 2,5-xylenol under aerobic conditions and 3,5-xylenol under anoxic conditions. The potential for natural attenuation of the phenols in this aquifer appear very promising....

  14. Geochemical detection of carbon dioxide in dilute aquifers

    Directory of Open Access Journals (Sweden)

    Aines Roger

    2009-03-01

    Full Text Available Abstract Background Carbon storage in deep saline reservoirs has the potential to lower the amount of CO2 emitted to the atmosphere and to mitigate global warming. Leakage back to the atmosphere through abandoned wells and along faults would reduce the efficiency of carbon storage, possibly leading to health and ecological hazards at the ground surface, and possibly impacting water quality of near-surface dilute aquifers. We use static equilibrium and reactive transport simulations to test the hypothesis that perturbations in water chemistry associated with a CO2 gas leak into dilute groundwater are important measures for the potential release of CO2 to the atmosphere. Simulation parameters are constrained by groundwater chemistry, flow, and lithology from the High Plains aquifer. The High Plains aquifer is used to represent a typical sedimentary aquifer overlying a deep CO2 storage reservoir. Specifically, we address the relationships between CO2 flux, groundwater flow, detection time and distance. The CO2 flux ranges from 103 to 2 × 106 t/yr (0.63 to 1250 t/m2/yr to assess chemical perturbations resulting from relatively small leaks that may compromise long-term storage, water quality, and surface ecology, and larger leaks characteristic of short-term well failure. Results For the scenarios we studied, our simulations show pH and carbonate chemistry are good indicators for leakage of stored CO2 into an overlying aquifer because elevated CO2 yields a more acid pH than the ambient groundwater. CO2 leakage into a dilute groundwater creates a slightly acid plume that can be detected at some distance from the leak source due to groundwater flow and CO2 buoyancy. pH breakthrough curves demonstrate that CO2 leaks can be easily detected for CO2 flux ≥ 104 t/yr within a 15-month time period at a monitoring well screened within a permeable layer 500 m downstream from the vertical gas trace. At lower flux rates, the CO2 dissolves in the aqueous phase

  15. Sustainability of natural attenuation of nitrate in agricultural aquifers

    Science.gov (United States)

    Green, Christopher T.; Bekins, Barbara A.

    2010-01-01

    Increased concentrations of nitrate in groundwater in agricultural areas, coinciding with increased use of chemical and organic fertilizers, have raised concern because of risks to environmental and human health. At some sites, these problems are mitigated by natural attenuation of nitrate as a result of microbially mediated reactions. Results from U.S. Geological Survey (USGS) research under the National Water-Quality Assessment (NAWQA) program show that reactions of dissolved nitrate with solid aquifer minerals and organic carbon help lower nitrate concentrations in groundwater beneath agricultural fields. However, increased fluxes of nitrate cause ongoing depletion of the finite pool of solid reactants. Consumption of the solid reactants diminishes the capacity of the aquifer to remove nitrate, calling into question the long-term sustainability of these natural attenuation processes.

  16. Geochemistry of the Cambrian-Ordovician aquifer system in the northern Midwest, United States: D in Regional aquifer-system analysis

    Science.gov (United States)

    Siegel, D.I.

    1989-01-01

    Distributions of solutes in aquifers of Cambrian and Ordovician age were studied in Minnesota, Wisconsin, Iowa, Illinois, northwestern Indiana, and northern Missouri to determine the sources of solutes and the probable chemical mechanisms that control regional variations in water quality. This work is part of the Northern Midwest Regional Aquifer-System Analysis project, whose objective is to describe and model the regional hydrogeology of the Cambrian- Ordovician aquifer system in the study region. The data base used included more than 3,000 ground-water-quality analyses from all major aquifers, but especially from the St. Peter, Jordan, and Mount Simon Sandstones and their equivalents. Regional variations in the water chemistry of glacial drift and other sedimentary units that overlie the Cambrian-Ordovician aquifer system in recharge areas in Minnesota, Iowa, Wisconsin, and Illinois were also studied, but to a lesser degree.

  17. Studies and projections of hydraulic conductivity of Devonian Plavinu and Daugava carbonate aquifers in Latvia

    Science.gov (United States)

    Perkone, E.; Delina, A.; Saks, T.; Raga, B.; Jātnieks, J.; Klints, I.; Popovs, K.; Babre, A.; Bikše, J.; Kalvāns, A.; Retike, I.; Ukass, J.

    2012-04-01

    Carbonate aquifers show a very wide range of hydrogeological characteristics. Carbonate rock hydrogeology display two extremes: on one hand hydrogeological properties of the carbonates are governed by the pathways of the preferential groundwater flow typical in karstic regions, on the other - some carbonate aquifers behave almost like a homogeneous, isotropic, porous medium. Most lie between these extremes, but these case variations complicates the study of carbonate aquifer properties. In this study the results of the hydraulic conductivity in carbonate aquifers measurements, hydraulic conductivity correlation between sediments lithology and the aquifer surface depth and fractures research is presented. Upper Devonian Frasnian stage Pļaviņu and Daugava carbonate aquifers in the Latvian part of the Baltic basin is considered. The aim of this research is to elaborate characteristic hydraulic conductivity values for each aquifer based on existing data of the pumping test results and other aquifer properties. Pļaviņu and Daugava carbonate aquifers mainly consist of jointed dolomite with intermediate layers of dolomitic marlstone, limestone, clays and gypsum. These aquifers are prevalent in most of the study area, except Northern and South - Eastern parts of the territory. In geological structure Daugava aquifer lies above Pļaviņu aquifer. Daugava aquifer depth changes from 10 - 20 and even less meters in Eastern part to 250 - 300 m in South - West part of study area, but thickness varies from few meters to 30 m. Pļaviņu aquifer surface depth varies from 20 - 30 m, but in uplands surface depth reaches more than 120 m, in Eastern part to more than 300 m in South - West part of study area. Aquifer average thickness varies from 20 - 40 m, but in areas with buried valleys thickness can be less than 10 meters. Outcrops of these sediments are occurring in banks of largest rivers and in some areas aquifers are karstified. In studies of the carbonate aquifers it is

  18. A Three-dimensional Model of Poroviscous Aquifer Deformation

    OpenAIRE

    Jeng, D. Isaac

    2005-01-01

    A mathematical model is developed for quantification of aquifer deformation due to ground-water withdrawal and, with some modifications, is potentially applicable to petroleum reservoirs. A porous medium saturated with water is conceptually treated in the model as a nonlinearly viscous fluid continuum. The model employs a new three-dimensional extension, made in this thesis, of Helm's poroviscosity as a constitutive law governing the stress-strain relation of material deformation and Gerse...

  19. Poroelastic loading of an aquifer due to upstream dam releases.

    Science.gov (United States)

    Boutt, David F

    2010-01-01

    Short-term changes in the hydraulic head of surface water bodies are known to influence the shallow response of hydraulically connected groundwaters. Associated with these fluctuations is the physical increase in stream water creating a mechanical load on the ground surface. This load is supported by the geologic materials (sediment or rock) and the pore fluid contained within the pores. Changes in this surface load have a direct effect on the total stress of the aquifer causing either a change in effective stress or fluid pressure. This response, predicted by the framework of linear poroelasticity, is a well-understood phenomenon in geologic materials. Currently, field measurements of the hydraulic response (i.e., fluid pressure) of aquifer materials are undergoing poroelastic loading due to dam releases in the Deerfield River Watershed in Massachusetts. An increase in stream stage from upstream dam releases causes an instantaneous pore fluid pressure increase at multiple depths and locations in the aquifer. This increase lasts anywhere from 15 to 40 minutes depending on the magnitude of the rise in the stream stage. Pore-pressure changes are well correlated to stream stage fluctuations for all of the recorded events. Poroelastic models created using basin stratigraphy and hydraulic properties of the aquifer response match the field observations well. Model results suggest that the overall stratigraphy is important in controlling the magnitude and duration of the poroelastic response. An improved understanding of responses such as these can be used to constrain uncertainties in model calibration and simulations of the contaminant migration in low permeability fine-grained (compressive) materials. PMID:20665952

  20. Hydrogeophysical methods for analyzing aquifer storage and recovery systems

    Energy Technology Data Exchange (ETDEWEB)

    Minsley, B.J.; Ajo-Franklin, J.; Mukhopadhyay, A.; Morgan, F.D.

    2009-12-01

    Hydrogeophysical methods are presented that support the siting and monitoring of aquifer storage and recovery (ASR) systems. These methods are presented as numerical simulations in the context of a proposed ASR experiment in Kuwait, although the techniques are applicable to numerous ASR projects. Bulk geophysical properties are calculated directly from ASR flow and solute transport simulations using standard petrophysical relationships and are used to simulate the dynamic geophysical response to ASR. This strategy provides a quantitative framework for determining site-specific geophysical methods and data acquisition geometries that can provide the most useful information about the ASR implementation. An axisymmetric, coupled fluid flow and solute transport model simulates injection, storage, and withdrawal of fresh water (salinity {approx}500 ppm) into the Dammam aquifer, a tertiary carbonate formation with native salinity approximately 6000 ppm. Sensitivity of the flow simulations to the correlation length of aquifer heterogeneity, aquifer dispersivity, and hydraulic permeability of the confining layer are investigated. The geophysical response using electrical resistivity, time-domain electromagnetic (TEM), and seismic methods is computed at regular intervals during the ASR simulation to investigate the sensitivity of these different techniques to changes in subsurface properties. For the electrical and electromagnetic methods, fluid electric conductivity is derived from the modeled salinity and is combined with an assumed porosity model to compute a bulk electrical resistivity structure. The seismic response is computed from the porosity model and changes in effective stress due to fluid pressure variations during injection/recovery, while changes in fluid properties are introduced through Gassmann fluid substitution.

  1. Testing water pollution in a two layer aquifer

    OpenAIRE

    García León, Manuel; Lin Ye, Jue

    2011-01-01

    Water bodies around urban areas may be polluted with chemical elements from urban or industrial activities. We study the case of underground water pollution. This is a serious problem, since under- ground water is high qualified drinkable water in a world where this natural resource is increasingly reduced. This study is focused on a two-layer aquifer. If the superficial layer is contaminated, the deeper layer could be spoiled as well. This contribution checks the equality of the mean or c...

  2. Data sources on aquifers - Descriptions; Datengrundlagen zu den Aquiferen

    Energy Technology Data Exchange (ETDEWEB)

    Wyss, R.

    2010-07-01

    This short report for the Swiss Federal Office of Energy (SFOE) is one of a series of appendices dealing with the potential for geological sequestration of carbon dioxide in Switzerland. This appendix provides details on the most important factors concerning CO{sub 2} sequestration in depths of 800 to 2,500 metres such as permeability, hydraulic pressures and salinity. The appendix notes various drilling activities and provides short overviews concerning the properties of the various geological aquifer layers.

  3. Multidisciplinary approach to identify aquifer-peatland connectivity

    Science.gov (United States)

    Larocque, Marie; Pellerin, Stéphanie; Cloutier, Vincent; Ferlatte, Miryane; Munger, Julie; Quillet, Anne; Paniconi, Claudio

    2015-04-01

    In southern Quebec (Canada), wetlands sustain increasing pressures from agriculture, urban development, and peat exploitation. To protect both groundwater and ecosystems, it is important to be able to identify how, where, and to what extent shallow aquifers and wetlands are connected. This study focuses on peatlands which are especially abundant in Quebec. The objective of this research was to better understand aquifer-peatland connectivity and to identify easily measured indicators of this connectivity. Geomorphology, hydrogeochemistry, and vegetation were selected as key indicators of connectivity. Twelve peatland transects were instrumented and monitored in the Abitibi (slope peatlands associated with eskers) and Centre-du-Quebec (depression peatlands) regions of Quebec (Canada). Geomorphology, geology, water levels, water chemistry, and vegetation species were identified/measured on all transects. Flow conditions were simulated numerically on two typical transects. Results show that a majority of peatland transects receives groundwater from a shallow aquifer. In slope peatlands, groundwater flows through the organic deposits towards the peatland center. In depression peatlands, groundwater flows only 100-200 m within the peatland before being redirected through surface routes towards the outlet. Flow modeling and sensitivity analysis have identified that the thickness and hydraulic conductivity of permeable deposits close to the peatland and beneath the organic deposits influence flow directions within the peatland. Geochemical data have confirmed the usefulness of total dissolved solids (TDS) exceeding 14 mg/L as an indicator of the presence of groundwater within the peatland. Vegetation surveys have allowed the identification of species and groups of species that occur mostly when groundwater is present, for instance Carex limosa and Sphagnum russowii. Geomorphological conditions (slope or depression peatland), TDS, and vegetation can be measured

  4. Extending Traditional Technology of Aquifer Characterization Through Numerical Models

    OpenAIRE

    Narasimhan, T. N.; Moran, Jean

    1996-01-01

    This is the final Technical Completion Report of Projects No. W-830 funded by the Water and Wildlands Resources Center of the University of California. This report consists of two parts. Part 1 entitled, "Hydraulic Characterization of Aquifers, Reservoir Rocks and Soils: A History of Ideas" is an integrated review of the development of hydraulic characterization methods in the fields of Civil Engineering, Soil Physics, Groundwater Hydrology and Petroleum Engineering. The narrative portion of ...

  5. Nitrite and Nitrate Removal Efficiencies of Soil Aquifer Treatment Columns

    OpenAIRE

    GÜNGÖR, Kerem; ÜNLÜ, Kahraman

    2005-01-01

    Bench-scale soil column experiments were performed to examine the effects of soil type and infiltration conditions on the removal efficiencies of wastewater nitrites and nitrates during the biological ripening phase of soil aquifer treatment (SAT) columns. SAT was simulated in three 1-m-high soil columns packed with 3 different natural agricultural soils having sandy clay loam (SCL), loamy sand (LS) and sandy loam (SL) textures. All columns were equipped with tensiometers and soil-wa...

  6. Policy and Economics of Managed Aquifer Recharge and Water Banking

    OpenAIRE

    Sharon B. Megdal; Peter Dillon

    2015-01-01

    Managed Aquifer Recharge (MAR) and water banking are of increasing importance to water resources management. MAR can be used to buffer against drought and changing or variable climate, as well as provide water to meet demand growth, by making use of excess surface water supplies and recycled waters. Along with hydrologic and geologic considerations, economic and policy analyses are essential to a complete analysis of MAR and water banking opportunities. The papers included in this Special Iss...

  7. Spatial and Temporal Infiltration Dynamics During Managed Aquifer Recharge

    OpenAIRE

    Racz, Andrew

    2014-01-01

    Natural groundwater recharge is inherently difficult to quantify and predict, largely because it comprises a series of processes that are spatially distributed and temporally variable. Infiltration ponds used for managed aquifer recharge (MAR) provide an opportunity to quantify recharge processes across multiple scales under semicontrolled conditions. We instrumented a 3-ha MAR infiltration pond to measure and compare infiltration patterns determined using whole-pond and point-specific method...

  8. Water security and services in the ocean-aquifer system

    Science.gov (United States)

    Taniguchi, M.

    2011-12-01

    Coastal vulnerability and water security are both important research subjects on global environmental problems under the pressures of changing climate and societies. A six years research project by RIHN on the coastal subsurface environments in seven Asia cities revealed that subsurface environmental problems including saltwater intrusion, groundwater contamination and subsurface thermal anomalies occurred one after another depending on the development stage of the cities during the last 100 years. Exchanges of water between ocean and aquifer in the coastal cities depend on driving force from land of natural resources capacities such as groundwater recharge rate, and social changes such as excessive groundwater pumping due to industrialization. Risk assessments and managements for aquifers which are parts of water security have been made for seven Asian coastal cities. On the other hand, submarine groundwater discharge (SGD) into the ocean provides water services directly to the coastal ecosystem through nutrient transports from land to the ocean. Constant geophysical and geochemical conditions served by SGD provide sustainable services to the coastal environment. Flora and fauna which prefer brackish water in the coastal zone depend on not only river water discharge but also SGD. Ocean -aquifer interaction can be found in the coastal ecosystem including sea shell, sea grass and fishes in the coastal zone though SGD. In order to evaluate a coastal security and sustainable environment, not only risk assessments due to disasters but also water services are important, and the both are evaluated in Asian coastal zones.

  9. The invertebrate ecology of the Chalk aquifer in England (UK)

    Science.gov (United States)

    Maurice, L.; Robertson, A. R.; White, D.; Knight, L.; Johns, T.; Edwards, F.; Arietti, M.; Sorensen, J. P. R.; Weitowitz, D.; Marchant, B. P.; Bloomfield, J. P.

    2016-03-01

    The Chalk is an important water supply aquifer, yet ecosystems within it remain poorly understood. Boreholes (198) in seven areas of England (UK) were sampled to determine the importance of the Chalk aquifer as a habitat, and to improve understanding of how species are distributed. Stygobitic macro-invertebrates were remarkably common, and were recorded in 67 % of boreholes in unconcealed Chalk, although they were not recorded in Chalk that is concealed by low-permeability strata and thus likely to be confined. Most species were found in shallow boreholes (50 m) water tables, indicating that the habitat is vertically extensive. Stygobites were present in more boreholes in southern England than northern England (77 % compared to 38 %). Only two species were found in northern England compared to six in southern England, but overall seven of the eight stygobitic macro-invertebrate species found in England were detected in the Chalk. Two species are common in southern England, but absent from northern England despite the presence of a continuous habitat prior to the Devensian glaciation. This suggests that either they did not survive glaciations in the north where glaciers were more extensive, or dispersal rates are slow and they have never colonised northern England. Subsurface ecosystems comprising aquatic macro-invertebrates and meiofauna, as well as the microbial organisms they interact with, are likely to be widespread in the Chalk aquifer. They represent an important contribution to biodiversity, and may influence biogeochemical cycles and provide other ecosystem services.

  10. Relationship of regional water quality to aquifer thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Allen, R.D.

    1983-11-01

    Ground-water quality and associated geologic characteristics may affect the feasibility of aquifer thermal energy storage (ATES) system development in any hydrologic region. This study sought to determine the relationship between ground-water quality parameters and the regional potential for ATES system development. Information was collected from available literature to identify chemical and physical mechanisms that could adversely affect an ATES system. Appropriate beneficiation techniques to counter these potential geochemical and lithologic problems were also identified through the literature search. Regional hydrology summaries and other sources were used in reviewing aquifers of 19 drainage regions in the US to determine generic geochemical characteristics for analysis. Numerical modeling techniques were used to perform geochemical analyses of water quality from 67 selected aquifers. Candidate water resources regions were then identified for exploration and development of ATES. This study identified six principal mechanisms by which ATES reservoir permeability may be impaired: (1) particulate plugging, (2) chemical precipitation, (3) liquid-solid reactions, (4) formation disaggregation, (5) oxidation reactions, and (6) biological activity. Specific proven countermeasures to reduce or eliminate these effects were found. Of the hydrologic regions reviewed, 10 were identified as having the characteristics necessary for ATES development: (1) Mid-Atlantic, (2) South-Atlantic Gulf, (3) Ohio, (4) Upper Mississippi, (5) Lower Mississippi, (6) Souris-Red-Rainy, (7) Missouri Basin, (8) Arkansas-White-Red, (9) Texas-Gulf, and (10) California.

  11. NMR Logging to Estimate Hydraulic Conductivity in Unconsolidated Aquifers.

    Science.gov (United States)

    Knight, Rosemary; Walsh, David O; Butler, James J; Grunewald, Elliot; Liu, Gaisheng; Parsekian, Andrew D; Reboulet, Edward C; Knobbe, Steve; Barrows, Mercer

    2016-01-01

    Nuclear magnetic resonance (NMR) logging provides a new means of estimating the hydraulic conductivity (K) of unconsolidated aquifers. The estimation of K from the measured NMR parameters can be performed using the Schlumberger-Doll Research (SDR) equation, which is based on the Kozeny-Carman equation and initially developed for obtaining permeability from NMR logging in petroleum reservoirs. The SDR equation includes empirically determined constants. Decades of research for petroleum applications have resulted in standard values for these constants that can provide accurate estimates of permeability in consolidated formations. The question we asked: Can standard values for the constants be defined for hydrogeologic applications that would yield accurate estimates of K in unconsolidated aquifers? Working at 10 locations at three field sites in Kansas and Washington, USA, we acquired NMR and K data using direct-push methods over a 10- to 20-m depth interval in the shallow subsurface. Analysis of pairs of NMR and K data revealed that we could dramatically improve K estimates by replacing the standard petroleum constants with new constants, optimal for estimating K in the unconsolidated materials at the field sites. Most significant was the finding that there was little change in the SDR constants between sites. This suggests that we can define a new set of constants that can be used to obtain high resolution, cost-effective estimates of K from NMR logging in unconsolidated aquifers. This significant result has the potential to change dramatically the approach to determining K for hydrogeologic applications. PMID:25810149

  12. Aquifer community structure in dependence of lithostratigraphy in groundwater reservoirs.

    Science.gov (United States)

    Beyer, Andrea; Rzanny, Michael; Weist, Aileen; Möller, Silke; Burow, Katja; Gutmann, Falko; Neumann, Stefan; Lindner, Julia; Müsse, Steffen; Brangsch, Hanka; Stoiber-Lipp, Jennifer; Lonschinski, Martin; Merten, Dirk; Büchel, Georg; Kothe, Erika

    2015-12-01

    Groundwater microbiology with respect to different host rocks offers new possibilities to describe and map the habitat harboring approximately half of Earths' biomass. The Thuringian Basin (Germany) contains formations of the Permian (Zechstein) and Triassic (Muschelkalk and Buntsandstein) with outcrops and deeper regions at the border and central part. Hydro(geo)chemistry and bacterial community structure of 11 natural springs and 20 groundwater wells were analyzed to define typical patterns for each formation. Widespread were Gammaproteobacteria, while Bacilli were present in all wells. Halotolerant and halophilic taxa were present in Zechstein. The occurrence of specific taxa allowed a clear separation of communities from all three lithostratigraphic groups. These specific taxa could be used to follow fluid movement, e.g., from the underlying Zechstein or from nearby saline reservoirs into Buntsandstein aquifers. Thus, we developed a new tool to identify the lithostratigraphic origin of sources in mixed waters. This was verified with entry of surface water, as species not present in the underground Zechstein environments were isolated from the water samples. Thus, our tool shows a higher resolution as compared to hydrochemistry, which is prone to undergo fast dilution if water mixes with other aquifers. Furthermore, the bacteria well adapted to their respective environment showed geographic clustering allowing to differentiate regional aquifers. PMID:26002361

  13. Modeling impact of small Kansas landfills on underlying aquifers

    Science.gov (United States)

    Sophocleous, M.; Stadnyk, N.G.; Stotts, M.

    1996-01-01

    Small landfills are exempt from compliance with Resource Conservation and Recovery Act Subtitle D standards for liner and leachate collection. We investigate the ramifications of this exemption under western Kansas semiarid environments and explore the conditions under which naturally occurring geologic settings provide sufficient protection against ground-water contamination. The methodology we employed was to run water budget simulations using the Hydrologic Evaluation of Landfill Performance (HELP) model, and fate and transport simulations using the Multimedia Exposure Assessment Model (MULTIMED) for several western Kansas small landfill scenarios in combination with extensive sensitivity analyses. We demonstrate that requiring landfill cover, leachate collection system (LCS), and compacted soil liner will reduce leachate production by 56%, whereas requiring only a cover without LCS and liner will reduce leachate by half as much. The most vulnerable small landfills are shown to be the ones with no vegetative cover underlain by both a relatively thin vadose zone and aquifer and which overlie an aquifer characterized by cool temperatures and low hydraulic gradients. The aquifer-related physical and chemical parameters proved to be more important than vadose zone and biodegradation parameters in controlling leachate concentrations at the point of compliance. ??ASCE.

  14. Hydrostratigraphy of a Sand Aquifer from Combined ERT and GPR

    Science.gov (United States)

    Papadimitrios, K. S.; Ferris, G.; Bank, C.

    2015-12-01

    Overlapping resistivity and ground-penetrating radar transects were collected on a shallow sand aquifer. The study area covers about 150 by 150 m, and the water table depth in that area ranges from as shallow as 30 cm to over 2m. Electric resistivity tomography shows layers of resistances which we relate to the vadose zone (above 1200 Ohm.m), the saturated zone (approx. 300 Ohm.m), and underlying aquitard (above 1200 Ohm.m, made of glacial till). The resistivity sections fail to capture the topography of the sand-till boundary seen in collected radargrams (e.g., from 80 to 120 ns over a 30 m horizontal distance). Converting radar travel times to thickness of the aquifer requires knowledge of water table depth as well as radar velocity in both the saturated and unsaturated sands. Water table depth can be taken from resistivity pseudosections as well as local piezometers. Radar velocities can be estimated based on the properties of the local sand and assuming 100% saturation. In merging the results from the two datasets we are able to map local hydrostratigraphy and aquifer geometry.

  15. Modeling Regional Seawater Intrusion Using One Model Layer Per Aquifer

    Science.gov (United States)

    Bakker, M.; Schaars, F.

    2012-12-01

    Seawater intrusion is an ongoing and expanding problem in coastal aquifers. A Dupuit formulation was developed to make it possible to simulate seawater intrusion using one model layer per aquifer. The formulation is implemented in the SWI package for MODFLOW. Aquifers don't need to be discretized vertically so that the evolution of the salinity distribution may be simulated in a timely manner on a regular Mac or PC. SWI may be applied to simulate seawater intrusion with an existing MODFLOW model through the addition of just one input file. SWI is envisioned to be complimentary to codes that solve the coupled flow and transport equations, such as SEAWAT and SUTRA: SWI may be used to simulate regional flow including density effects, and other codes may be used to simulate local seawater intrusion, including dispersive mixing. Since its first release in 2004, SWI has been benchmarked against several other codes and was shown to perform well, even when a moderate amount of dispersion was included in the simulations. SWI has recently been implemented in MODFLOW2005. The new implementation includes a number of enhancements such as variable time stepping, separate budgets for fresh and salt water, and the ability to simulate upconing through aquitards. In the presentation, the main features of the SWI package are discussed, the new capabilities are showcased, and several examples are presented.

  16. Coastal Aquifer Response to Environmental Change - Implications for Future Projections

    Science.gov (United States)

    Post, V.

    2014-12-01

    Coastal aquifers are important resources for water supply, and are increasingly stressed by population increase and the growing water demand for irrigation and other uses. Concern exists that these current pressures will be compunded by the adverse impacts of future environmental change, in particular sea-level rise. Numerous studies have investigated the effect of the expected sea-level rise durring the 21st century on the salintiy distribution in coastal groundwater systems. In many of these studies, the predicted changes due to an increase in sea level are typically seen as a departure from a steady-state situation. But many other studies have provided abundant evidence that groundwater systems in coastal areas are not in equilibrium with the present-day boundary conditions, i.e., coastline configuration and climate. This is borne out by, for example, the salinity distribution of groundwater, which does not obey the classical configuration of an intruded wedge of seawater extending inland from the coastline. This paper will argue that coastal aquifers systems are in a continuous state of transition. The relevance of future environmental change within the context of long-term trends will be discussed and exemplified by case studies of coastal aquifers in different parts of the world. It will be argued that the conceptualization of coastal groundwater systems, and in particular the connection between their onshore and offshore parts, is a major source of uncertainty in studies that aim to quantify the impact of sea-level rise on coastal groundwater resources.

  17. Anaerobic degradation of alkylated benzenes in denitrifying laboratory aquifer columns

    International Nuclear Information System (INIS)

    Toluene and m-xylene were rapidly mineralized in an anaerobic laboratory aquifer column operated under continuous-flow conditions with nitrate as an electron acceptor. The oxidation of toluene and m-xylene was coupled with the reduction of nitrate, and mineralization was confirmed by trapping 14CO2 evolved from 14C-ring-labeled substrates. Substrate degradation also took place when nitrous oxide replaced nitrate as an electron acceptor, but decomposition was inhibited in the presence of molecular oxygen or after the substitution of nitrate by nitrite. The m-xylene-adapted microorganisms in the aquifer column degraded toluene, benzaldehyde, benzoate, m-toluylaldehyde, m-toluate, m-cresol, p-cresol, and p-hydroxybenzoate but were unable to metabolize benzene, naphthalene, methylcyclohexane, and 1,3-dimethylcyclohexane. Isotope-dilution experiments suggested benzoate as an intermediate formed during anaerobic toluene metabolism. The finding that the highly water-soluble nitrous oxide served as electron acceptor for the anaerobic mineralization of some aromatic hydrocarbons may offer attractive options for the in situ restoration of polluted aquifers

  18. Geospatial compilation of historical water-level altitudes in the Chicot and Evangeline aquifers 1977-2013 and Jasper aquifer 2000-13 in the Gulf Coast aquifer system, Houston-Galveston Region, Texas

    Science.gov (United States)

    Johnson, Michaela R.; Ellis, Robert H.H.

    2013-01-01

    The U.S. Geological Survey (USGS) in cooperation with the Harris-Galveston Subsidence District, City of Houston, Fort Bend Subsidence District, Lone Star Groundwater Conservation District, and Brazoria County Groundwater Conservation District has produced a series of annual reports depicting groundwater-level altitudes in the Chicot, Evangeline, and Jasper aquifers of the Gulf Coast aquifer system in the Houston-Galveston region, Texas. To produce these annual reports, contours of equal water-level altitudes are created from water levels measured between December and March of each year from groundwater wells screened completely within one of these three aquifers. Information obtained from maps published in the annual series of USGS reports and geospatial datasets of water-level altitude contours used to create the annual series of USGS reports were compiled into a comprehensive geodatabase. The geospatial compilation contains 88 datasets from previously published contour maps showing water-level altitudes for each primary aquifer of the Gulf Coast aquifer system, 37 for the Chicot (1977–2013), 37 for the Evangeline aquifer (1977–2013), and 14 for the Jasper aquifer (2000–13).

  19. Spatial variability of hydraulic conductivity of an unconfined sandy aquifer determined by a mini slug test

    DEFF Research Database (Denmark)

    Bjerg, Poul Løgstrup; Hinsby, Klaus; Christensen, Thomas Højlund;

    1992-01-01

    The spatial variability of the hydraulic conductivity in a sandy aquifer has been determined by a mini slug test method. The hydraulic conductivity (K) of the aquifer has a geometric mean of 5.05 × 10−4 m s−1, and an overall variance of 1n K equal to 0.37 which corresponds quite well to the results...... obtained by two large scale tracer experiments performed in the aquifer. A geological model of the aquifer based on 31 sediment cores, proposed three hydrogeological layers in the aquifer concurrent with the vertical variations observed with respect to hydraulic conductivity. The horizontal correlation...... length of the hydraulic conductivity has been determined for each of the three hydrogeological layers and is found to be small (1–2.5 m). The asymptotic longitudinal dispersivity of the aquifer has been estimated from the variance in hydraulic conductivity and the horizontal correlation length...

  20. Quality of water in the Trinity and Edwards aquifers, south-central Texas, 1996-98

    Science.gov (United States)

    Fahlquist, Lynne; Ardis, Ann F.

    2004-01-01

    During 1996?98, the U.S. Geological Survey studied surface- and ground-water quality in south-central Texas. The ground-water components included the upper and middle zones (undifferentiated) of the Trinity aquifer in the Hill Country and the unconfined part (recharge zone) and confined part (artesian zone) of the Edwards aquifer in the Balcones fault zone of the San Antonio region. The study was supplemented by information compiled from four ground-water-quality studies done during 1996?98. Trinity aquifer waters are more mineralized and contain larger dissolved solids, sulfate, and chloride concentrations compared to Edwards aquifer waters. Greater variability in water chemistry in the Trinity aquifer likely reflects the more variable lithology of the host rock. Trace elements were widely detected, mostly at small concentrations. Median total nitrogen was larger in the Edwards aquifer than in the Trinity aquifer. Ammonia nitrogen was detected more frequently and at larger concentrations in the Trinity aquifer than in the Edwards aquifer. Although some nitrate nitrogen concentrations in the Edwards aquifer exceeded a U.S. Geological Survey national background threshold concentration, no concentrations exceeded the U.S. Environmental Protection Agency public drinking-water standard. Synthetic organic compounds, such as pesticides and volatile organic compounds, were detected in the Edwards aquifer and less frequently in the Trinity aquifer, mostly at very small concentrations (less than 1 microgram per liter). These compounds were detected most frequently in urban unconfined Edwards aquifer samples. Atrazine and its breakdown product deethylatrazine were the most frequently detected pesticides, and trihalomethanes were the most frequently detected volatile organic compounds. Widespread detections of these compounds, although at small concentrations, indicate that anthropogenic activities affect ground-water quality. Radon gas was detected throughout the Trinity

  1. Hydrologic and Geochemical Evaluation of Aquifer Storage Recovery in the Santee Limestone/Black Mingo Aquifer, Charleston, South Carolina, 1998-2002

    Science.gov (United States)

    Petkewich, Matthew D.; Parkhurst, David L.; Conlon, Kevin J.; Campbell, Bruce G.; Mirecki, June E.

    2004-01-01

    The hydrologic and geochemical effects of aquifer storage recovery were evaluated to determine the potential for supplying the city of Charleston, South Carolina, with large quantities of potable water during emergencies, such as earthquakes, hurricanes, or hard freezes. An aquifer storage recovery system, including a production well and three observation wells, was installed at a site located on the Charleston peninsula. The focus of this study was the 23.2-meter thick Tertiary-age carbonate and sand aquifer of the Santee Limestone and the Black Mingo Group, the northernmost equivalent of the Floridan aquifer system. Four cycles of injection, storage, and recovery were conducted between October 1999 and February 2002. Each cycle consisted of injecting between 6.90 and 7.19 million liters of water for storage periods of 1, 3, or 6 months. The volume of recovered water that did not exceed the U.S. Environmental Protection Agency secondary standard for chloride (250 milligrams per liter) varied from 1.48 to 2.46 million liters, which is equivalent to 21 and 34 percent of the total volume injected for the individual tests. Aquifer storage recovery testing occurred within two productive zones of the brackish Santee Limestone/Black Mingo aquifer. The individual productive zones were determined to be approximately 2 to 4 meters thick, based on borehole geophysical logs, electromagnetic flow-meter testing, and specific-conductance profiles collected within the observation wells. A transmissivity and storage coefficient of 37 meters squared per day and 3 x 10-5, respectively, were determined for the Santee Limestone/Black Mingo aquifer. Water-quality and sediment samples collected during this investigation documented baseline aquifer and injected water quality, aquifer matrix composition, and changes in injected/aquifer water quality during injection, storage, and recovery. A total of 193 water-quality samples were collected and analyzed for physical properties, major and

  2. Hydrogeology and water quality of the Floridan aquifer system and effects of Lower Floridan aquifer pumping on the Upper Floridan aquifer at Fort Stewart, Georgia

    Science.gov (United States)

    Clarke, John S.; Cherry, Gregory C.; Gonthier, Gerard J.

    2011-01-01

    Test drilling, field investigations, and digital modeling were completed at Fort Stewart, GA, during 2009?2010, to assess the geologic, hydraulic, and water-quality characteristics of the Floridan aquifer system and evaluate the effect of Lower Floridan aquifer (LFA) pumping on the Upper Floridan aquifer (UFA). This work was performed pursuant to the Georgia Environmental Protection Division interim permitting strategy for new wells completed in the LFA that requires simulation to (1) quantify pumping-induced aquifer leakage from the UFA to LFA, and (2) identify the equivalent rate of UFA pumping that would produce the same maximum drawdown in the UFA that anticipated pumping from LFA well would induce. Field investigation activities included (1) constructing a 1,300-foot (ft) test boring and well completed in the LFA (well 33P028), (2) constructing an observation well in the UFA (well 33P029), (3) collecting drill cuttings and borehole geophysical logs, (4) collecting core samples for analysis of vertical hydraulic conductivity and porosity, (5) conducting flowmeter and packer tests in the open borehole within the UFA and LFA, (6) collecting depth-integrated water samples to assess basic ionic chemistry of various water-bearing zones, and (7) conducting aquifer tests in new LFA and UFA wells to determine hydraulic properties and assess interaquifer leakage. Using data collected at the site and in nearby areas, model simulation was used to assess the effects of LFA pumping on the UFA. Borehole-geophysical and flowmeter data indicate the LFA at Fort Stewart consists of limestone and dolomitic limestone between depths of 912 and 1,250 ft. Flowmeter data indicate the presence of three permeable zones at depth intervals of 912-947, 1,090-1,139, and 1,211?1,250 ft. LFA well 33P028 received 50 percent of the pumped volume from the uppermost permeable zone, and about 18 and 32 percent of the pumped volume from the middle and lowest permeable zones, respectively. Chemical

  3. Is Hazardous Waste Injection into Basal Aquifers a Good Idea?

    Science.gov (United States)

    Zhang, Y.; Person, M. A.; Rupp, J.; Celia, M. A.; Gable, C. W.; Bowen, B. B.; Mozley, P. S.; Evans, J. P.; Dewers, T. A.

    2012-12-01

    The recent induced M3.8 - M5.5 seismic events across the midcontinent, USA have raised concern regarding regulations for hazardous waste injection. It is also important to note that in the midcontinent region, the Illinois Basin is the main target for storing CO2 up to 1 million metric tons over a 3-year period in the CCS project of DOE. Here we present a hydrogeologic-geomechanical sensitivity study using a hybrid analytic-numerical cross-sectional model to assess a wide variety of possible failure scenarios within crystalline rocks. The hydrostratigraphic framework model we used in this study is based on the geology of the Illinois Basin. The model includes 2.8 km thick Paleozoic sedimentary aquifers and confining units underlain by 4 km of bedrock. We represented injection at 1000 gallons per minute (3785 liters per minute) into a basal sandstone aquifer (Mt. Simon Sandstone) as well as the overlying carbonate and siliciclastic reservoirs (middle aquifer: Knox Dolomite, St. Peter Sandstone, upper Ordovician Carbonates). In some scenarios, we included high/low permeability vertical and sub-horizontal thrust faults. Deviatoric pore pressures from the model were used to estimate failure along critically stressed faults within the bedrock. For a basement permeability between 10-15 m2 to 10-16 m2, injection into the basal aquifer (Mt. Simon sandstone) resulted in a failure envelop within the crystalline basement to depths of about 1.4 - 4 km and extending laterally up to 6 km. Including a transmissive vertical normal fault increased the depth of the failure envelope to 4 km below the base of the sedimentary pile. If a 108 order of magnitude permeability contrast exists between the thrust fault (10-10 m2) and basement rocks (10-18 m2), then pore pressures can propagate along a sub-horizontal fault about 12 km from the injection well. For middle aquifer injection, the presence of a bottom seal (Eau Claire Formation) has a prophylactic effect, preventing downward

  4. A quantitative analysis of hydraulic interaction processes in stream-aquifer systems

    OpenAIRE

    Wenke Wang; Zhenxue Dai; Yaqian Zhao; Junting Li; Lei Duan; Zhoufeng Wang; Lin Zhu

    2016-01-01

    The hydraulic relationship between the stream and aquifer can be altered from hydraulic connection to disconnection when the pumping rate exceeds the maximum seepage flux of the streambed. This study proposes to quantitatively analyze the physical processes of stream-aquifer systems from connection to disconnection. A free water table equation is adopted to clarify under what conditions a stream starts to separate hydraulically from an aquifer. Both the theoretical analysis and laboratory tes...

  5. Hydrochemical properties of deep carbonate aquifers in the SW German Molasse basin

    OpenAIRE

    Stober, I.; Bucher, K

    2015-01-01

    Background The Upper Jurassic (Malm) limestone and the Middle Triassic Muschelkalk limestone 18 are the major thermal aquifers in the southwest German alpine foreland. The aquifers 19 are of interest for production of geothermal energy and for balneological purposes. Methods Hydrochemical data from several hundred wells within two deep limestone aquifers in the Molasse basin of SW Germany have been compiled, examined, validated, and analyzed with the aim to characterize the fluids...

  6. Drainage structures and transit-time distributions in conduit-dominated and fissured karst aquifer systems

    OpenAIRE

    Lauber, Ute

    2014-01-01

    Karst aquifers are important groundwater resources. Solutionally-enlarged conduits embedded in a fissured rock matrix result in a highly heterogeneous underground drainage pattern that makes karst aquifers difficult to characterize. This thesis emphasizes the identification of drainage structures and the quantification of related transit-time distributions of diverse karst aquifer systems. Applied methods include artificial tracer tests, natural tracer analysis, and discharge analysis.

  7. Robust evidence for random fractal scaling of ground water levels in unconfined aquifers

    OpenAIRE

    Little, Max A.; Bloomfield, John P.

    2010-01-01

    This study introduces new approaches to improve the statistical robustness of techniques for quantifying the fractal scaling of groundwater levels, and uses these techniques to investigate scaling of groundwater levels from a consolidated permeable carbonate aquifer. Six groundwater level time series and an associated river stage time series from the unconfined Chalk aquifer (a dual-porosity, fractured limestone aquifer) in the Pang–Lambourn catchment, UK, have been analysed. Surrogate data o...

  8. Heat tracer test in an alluvial aquifer: field experiment and inverse modelling

    OpenAIRE

    Klepikova, Maria; Wildemeersch, Samuel; Jamin, Pierre; Orban, Philippe; Hermans, Thomas; Nguyen, Frédéric; Brouyère, Serge; Dassargues, Alain

    2016-01-01

    Using heat as an active tracer for aquifer characterization is a topic of increasing interest. In this study, we investigate the potential of using heat tracer tests for characterization of a shallow alluvial aquifer. A thermal tracer test was conducted in the alluvial aquifer of the Meuse River, Belgium. The tracing experiment consisted in simultaneously injecting heated water and a dye tracer in a piezometer and monitoring the evolution of groundwater temperature and tracer concentration in...

  9. Heat tracer and solute tests in an alluvial aquifer: field experiment and inverse modelling

    OpenAIRE

    Dassargues, Alain; Klepikova, Maria; Jamin, Pierre; Orban, Philippe; Brouyère, Serge

    2015-01-01

    Using heat as an active tracer in different types of aquifers is a topic of increasing interest. In this study, we investigate the potential interest of using heat tracer tests for characterization of a shallow alluvial aquifer. A thermal tracer test was conducted in the alluvial aquifer of the Meuse River, Belgium. The tracing experiment consisted in simultaneously injecting heated water and a dye tracer in a piezometer and monitoring the evolution of groundwater temperature and tracer conce...

  10. Basement topography and fresh-water resources of the coastal aquifer at Acapetahua, Chiapas, Mexico

    OpenAIRE

    Birgit Steinich; Gerardo Bocanegra; Eva Sánchez

    1999-01-01

    The coastal aquifer of Acapetahua, Chiapas, southeastern Mexico, consists of one hydrostratigraphic unit composed of continental sediments overlying a crystalline basement. Twenty-four resistivity soundings were conducted and fifty-one water samples were taken in order to determine basic aquifer characteristics such as aquifer geometry and fresh water reserves. The basement topography in the study area is characterized by hills and deep valleys with highly variable basement depths ranging fro...

  11. Aquifer Depletion and the Cost of Water Conservation: The Southern High Plains of Texas Case

    OpenAIRE

    Wheeler, Erin A.; Segarra, Eduardo; Johnson, Phillip N.; Willis, David B.; Johnson, Jeffrey W.

    2006-01-01

    Irrigated agriculture has played a vital role in the development and growth of the Great Plains Region of the United States. The primary source of water for irrigation in this region is the Ogallala Aquifer. The Southern portion of the Ogallala Aquifer is considered exhaustible due to the low level of recharge relative to the quantities of water pumped. Analysis and evaluation of water conservation policies which could extend the economic life of the Ogallala Aquifer in the Southern High Plai...

  12. Numerical long-term assessment of managed aquifer recharge from a reservoir into a karst aquifer in Jordan

    Science.gov (United States)

    Xanke, Julian; Jourde, Hervé; Liesch, Tanja; Goldscheider, Nico

    2016-09-01

    In semi-arid regions with high seasonal variability of water availability, adaptive management strategies and technical measures are required to ensure the sustainable use of water resources. In this study, managed recharge of storm water into a karst aquifer and the water level fluctuations related to pumping in a nearby wellfield were simulated at Wadi Wala, Jordan. We used a numerical equivalent porous medium (EPM) approach with specific adaptations to account for the heterogeneity and anisotropy of the karst aquifer. The model domain was vertically projected along the wadi course, resulting in a 2-dimensional model, and subdivided into hydraulic zones representing the karst-specific flow pattern of fast flow and slow depletion. Results show satisfying agreement of measured and simulated groundwater tables from 2002 to 2012 and predict a lowering of the average groundwater table until 2022 of around 2.7 m in the immediate surroundings of the reservoir and an increased depletion towards the wellfield, mainly caused by sedimentation in the reservoir and an associated decrease in infiltration. Abstraction at the wellfield changed considerably over the regarded time period and strongly influences the groundwater fluctuations, which shows the need of improved pumping management and monitoring. The results can serve as a basis for decision makers regarding an optimization of water management at the reservoir and wellfield. Furthermore, the presented numerical approach can be transferred to karst regions with similar physio-geographical conditions to assess managed aquifer recharge.

  13. Groundwater-flow modeling in the Yucatan karstic aquifer, Mexico

    Science.gov (United States)

    González-Herrera, Roger; Sánchez-y-Pinto, Ismael; Gamboa-Vargas, José

    2002-09-01

    The current conceptual model of the unconfined karstic aquifer in the Yucatan Peninsula, Mexico, is that a fresh-water lens floats above denser saline water that penetrates more than 40 km inland. The transmissivity of the aquifer is very high so the hydraulic gradient is very low, ranging from 7-10 mm/km through most of the northern part of the peninsula. The computer modeling program AQUIFER was used to investigate the regional groundwater flow in the aquifer. The karstified zone was modeled using the assumption that it acts hydraulically similar to a granular, porous medium. As part of the calibration, the following hypotheses were tested: (1) karstic features play an important role in the groundwater-flow system; (2) a ring or belt of sinkholes in the area is a manifestation of a zone of high transmissivity that facilitates the channeling of groundwater toward the Gulf of Mexico; and (3) the geologic features in the southern part of Yucatan influence the groundwater-flow system. The model shows that the Sierrita de Ticul fault, in the southwestern part of the study area, acts as a flow barrier and head values decline toward the northeast. The modeling also shows that the regional flow-system dynamics have not been altered despite the large number of pumping wells because the volume of water pumped is small compared with the volume of recharge, and the well-developed karst system of the region has a very high hydraulic conductivity. Résumé. Le modèle conceptuel classique de l'aquifère karstique libre de la péninsule du Yucatan (Mexique) consiste en une lentille d'eau douce flottant sur une eau salée plus dense qui pénètre à plus de 40 km à l'intérieur des terres. La transmissivité de l'aquifère est très élevée, en sorte que le gradient hydraulique est très faible, compris entre 7 et 10 mm/km dans la plus grande partie du nord de la péninsule. Le modèle AQUIFER a été utilisé pour explorer les écoulements souterrains régionaux dans cet

  14. 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

  15. Landfill leachate effects on sorption of organic micropollutants onto aquifer materials

    DEFF Research Database (Denmark)

    Larsen, Thomas; Christensen, Thomas Højlund; Pfeffer, Fred M.;

    1992-01-01

    content. The experiments showed that hydrophobic organic micropollutants do partition into dissolved organic carbon found in landfill leachate potentially increasing their mobility. However, landfill leachate interacted with aquifer materials apparently increases the sorbent affinity for the hydrophobic......The effect of dissolved organic carbon as present in landfill leachate, on the sorption of organic micropollutants in aquifer materials was studied by laboratory batch and column experiments involving 15 non-polar organic chemicals, 5 landfill leachates and 4 aquifer materials of low organic carbon......, the effect of landfill leachate on retardation of organic micropollutants in aquifer material seems limited....

  16. Middle Claiborne Aquifer: Alabama, Arkansas, Illinois, Kentucky, Louisiana, Missouri, Mississippi, Tennessee 2006-2008

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Digital hydrogeologic surface of the Middle Claiborne Aquifer in Alabama, Arkansas, Illinois, Kentucky, Louisiana, Missouri, Mississippi, Tennessee. The...

  17. Geology and hydrology of the deep bedrock aquifers in eastern Colorado

    Science.gov (United States)

    Robson, S.G.; Banta, E.R.

    1987-01-01

    Deep bedrock aquifers are present in rocks of Cretaceous through Pennsylvanian age in eastern Colorado. These aquifers are the Laramie-Fox Hills (the uppermost aquifer studied), Fort Hays-Codell, Dakota-Cheyenne, Entrada-Dockum, Lyons, and Fountain. Structural mapping indicates the aquifers are 2,000 to 9,000 ft below land surface in most of eastern Colorado but outcrop in local areas in a narrow band along the Front Range of the Rocky Mountains. Recharge primarily occurs in outcrops and produces a northerly or easterly groundwater flow to discharge areas along the South Platte or Arkansas Rivers. Deep aquifers also discharge by underflow to Kansas and Nebraska. Some water-yielding strata in the Dakota-Cheyenne aquifer are not in hydraulic connection with the aquifer, and abnormal fluid pressures, trapped hydrocarbons, and high dissolved-solids concentrations are found in these strata. Temperature and dissolved-solids mapping indicate water temperatures of 100 to 210 in northeastern Colorado and a zone of relatively fresh water extending through a 7,000 sq mi area of the Dakota-Cheyenne aquifer in southeastern Colorado. Water levels in the Laramie-Fox Hills aquifer continue to decline as much as 12 ft/yr in local areas near Denver. (USGS)

  18. Aquifer response to recharge-discharge phenomenon: inference from well hydrographs for genetic classification

    Science.gov (United States)

    Mukherjee, Arunangshu; Gupta, Anita; Ray, Ranjan Kumar; Tewari, Dinesh

    2015-05-01

    The continuous groundwater level data emanating from a high-frequency automatic water level recorder installed in a purpose-built piezometer provides a true hydrograph. Analyses of such hydrographs fairly reflect the aquifer character and can be used to draw inference for genetic classification of hard rock aquifers. The signature shape of annual water level fluctuation curve (annual cycle) of a piezometer is due to the specific character of the aquifer and the way it responds to the recharge-discharge phenomenon. The pattern of annual cycle remains identical year after year, although its magnitude may vary with the annual quantum of recharge-discharge. Lithology of the aquifer does not control the shape of the curve. Based on the crest and trough shape, the hard rock aquifers of Peninsular India, where the monsoonal pattern of rainfall occurs, have been classified into genetic groups. It is also found that the nature of the aquifer can be determined by visual comparison of apparent line thickness of the hydrograph, where thin lines denote unconfined aquifer and the apparently thicker lines correspond to confining condition. The response of an aquifer to a pumping event can be identified and separated by its pattern. Thus, the aquifer classification can be automated by adopting the proposed classification scheme.

  19. Disposal of carbon dioxide in aquifers in the U.S.

    Energy Technology Data Exchange (ETDEWEB)

    Winter, E.M.; Bergman, P.D.

    1995-11-01

    Deep saline aquifers were investigated as potential disposal sites for CO{sub 2}. The capacity of deep aquifers for CO{sub 2} disposal in the U.S. is highly uncertain. A rough estimate, derived from global estimates, is 5,500 Gt of CO{sub 2}. Saline aquifers underlie the regions in the U.S. where most utility power plants are situated. Therefore, approximately 65 percent of CO{sub 2} from power plants could possibly be injected directly into deep saline aquifers below these plants, without the need for long pipelines.

  20. Hydrogeology and water quality of the Floridan aquifer system and effect of Lower Floridan aquifer pumping on the Upper Floridan aquifer at Hunter Army Airfield, Chatham County, Georgia

    Science.gov (United States)

    Clarke, John S.; Williams, Lester J.; Cherry, Gregory C.

    2010-01-01

    Test drilling and field investigations, conducted at Hunter Army Airfield (HAAF), Chatham County, Georgia, during 2009, were used to determine the geologic, hydraulic, and water-quality characteristics of the Floridan aquifer system and to evaluate the effect of Lower Floridan aquifer (LFA) pumping on the Upper Floridan aquifer (UFA). Field investigation activities included (1) constructing a 1,168-foot (ft) test boring and well completed in the LFA, (2) collecting drill cuttings and borehole geophysical logs, (3) collecting core samples for analysis of vertical hydraulic conductivity and porosity, (4) conducting flowmeter and packer tests in the open borehole within the UFA and LFA, (5) collecting depth-integrated water samples to assess basic ionic chemistry of various water-bearing zones, and (6) conducting aquifer tests in the new LFA well and in an existing UFA well to determine hydraulic properties and assess interaquifer leakage. Using data collected at the site and in nearby areas, model simulation was used to quantify the effects of interaquifer leakage on the UFA and to determine the amount of pumping reduction required in the UFA to offset drawdown resulting from the leakage. Borehole-geophysical and flowmeter data indicate the LFA at HAAF consists of limestone and dolomitic limestone between depths of 703 and 1,080 ft, producing water from six major permeable zones: 723-731; 768-785; 818-837; 917-923; 1,027-1,052; and 1,060-1,080 ft. Data from a flowmeter survey, conducted at a pumping rate of 748 gallons per minute (gal/min), suggest that the two uppermost zones contributed 469 gal/min or 62.6 percent of the total flow during the test. The remaining four zones contributed from 1.7 to 18 percent of the total flow. Grab water samples indicate that with the exception of fluoride, constituent concentrations in the LFA increased with depth; water from the deepest interval (1,075 ft) contained chloride and sulfate concentrations of 480 and 240 milligrams per

  1. DS926 Digital surfaces and thicknesses of selected hydrogeologic units of the Floridan aquifer system in Florida and parts of Georgia, Alabama, and South Carolina -- Extent lines for permeable zones of the intermediate aquifer system and Brunswick aquifer system

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Digital surfaces and thicknesses of selected hydrogeologic units of the Floridan aquifer system were developed to define an updated hydrogeologic framework as part...

  2. Alluvial and bedrock aquifers of the Denver Basin; eastern Colorado's dual ground-water resource

    Science.gov (United States)

    Robson, Stanley G.

    1989-01-01

    Large volumes of ground water are contained in alluvial and bedrock aquifers in the semiarid Denver basin of eastern Colorado. The bedrock aquifer, for example, contains 1.2 times as much water as Lake Erie of the Great Lakes, yet it supplies only about 9 percent of the ground water used in the basin. Although this seems to indicate underutilization of this valuable water supply, this is not necessarily the case, for many factors other than the volume of water in the aquifer affect the use of the aquifer. Such factors as climatic conditions, precipitation runoff, geology and water-yielding character of the aquifers, water-level conditions, volume of recharge and discharge, legal and economic constraints, and water-quality conditions can ultimately affect the decision to use ground water. Knowledge of the function and interaction of the various parts of this hydrologic system is important to the proper management and use of the ground-water resources of the region. The semiarid climatic conditions on the Colorado plains produce flash floods of short duration and large peak-flow rates. However, snowmelt runoff from the Rocky Mountains produces the largest volumes of water and is typically of longer duration with smaller peak-flow rates. The alluvial aquifer is recharged easily from both types of runoff and readily stores and transmits the water because it consists of relatively thin deposits of gravel, sand, and clay located in the valleys of principal streams. The bedrock aquifer is recharged less easily because of its greater thickness (as much as 3,000 feet) and prevalent layers of shale which retard the downward movement of water in the formations. Although the bedrock aquifer contains more than 50 times as much water in storage as the alluvial aquifer, it does not store and transmit water as readily as the alluvial aquifer. For example, about 91 percent of the water pumped from wells is obtained from the alluvial aquifer, yet water-level declines generally have

  3. The quality of our Nation's waters: water quality in the Upper Floridan aquifer and overlying surficial aquifers, southeastern United States, 1993-2010

    Science.gov (United States)

    Berndt, Marian P.; Katz, Brian G.; Kingsbury, James A.; Crandall, Christy A.

    2015-01-01

    About 10 million people rely on groundwater from the Upper Floridan and surficial aquifers for drinking water. The Upper Floridan aquifer also is of primary importance to the region as a source of water for irrigation and as a source of crystal clear water that discharges to springs and streams providing recreational and tourist destinations and unique aquatic habitats. The reliance of the region on the Upper Floridan aquifer for drinking water and for the tourism and agricultural economies highlights the importance of long-term management to sustain the availability and quality of these resources.

  4. A method to investigate inter-aquifer leakage using hydraulics and multiple environmental tracers

    Science.gov (United States)

    Priestley, Stacey; Love, Andrew; Wohling, Daniel; Post, Vincent; Shand, Paul; Kipfer, Rolf; Tyroller, Lina

    2016-04-01

    Informed aquifer management decisions regarding sustainable yields or potential exploitation require an understanding of the groundwater system (Alley et al. 2002, Cherry and Parker 2004). Recently, the increase in coal seam gas (CSG) or shale gas production has highlighted the need for a better understanding of inter-aquifer leakage and contaminant migration. In most groundwater systems, the quantity or location of inter-aquifer leakage is unknown. Not taking into account leakage rates in the analysis of large scale flow systems can also lead to significant errors in the estimates of groundwater flow rates in aquifers (Love et al. 1993, Toth 2009). There is an urgent need for robust methods to investigate inter-aquifer leakage at a regional scale. This study builds on previous groundwater flow and inter-aquifer leakage studies to provide a methodology to investigate inter-aquifer leakage in a regional sedimentary basin using hydraulics and a multi-tracer approach. The methodology incorporates geological, hydrogeological and hydrochemical information in the basin to determine the likelihood and location of inter-aquifer leakage. Of particular benefit is the analysis of hydraulic heads and environmental tracers at nested piezometers, or where these are unavailable bore couplets comprising bores above and below the aquitard of interest within a localised geographical area. The proposed methodology has been successful in investigating inter-aquifer leakage in the Arckaringa Basin, South Australia. The suite of environmental tracers and isotopes used to analyse inter-aquifer leakage included the stable isotopes of water, radiocarbon, chloride-36, 87Sr/86Sr and helium isotopes. There is evidence for inter-aquifer leakage in the centre of the basin ~40 km along the regional flow path. This inter-aquifer leakage has been identified by a slight draw-down in the upper aquifer during pumping in the lower aquifer, overlap in Sr isotopes, δ2H, δ18O and chloride

  5. Predictability, stationarity, and classification of hydraulic responses to recharge in two karst aquifers

    Directory of Open Access Journals (Sweden)

    A. J. Long

    2012-08-01

    Full Text Available Karst aquifers, many of which are rapidly filled and depleted, are likely to be highly susceptible to changes in short-term climate variability. Here we explore methods that could be applied to model site-specific hydraulic responses, with the intent of simulating these responses to different climate scenarios from high-resolution climate models. We compare hydraulic responses (spring flow, groundwater level, and stream base flow at several sites in two karst aquifers: the Edwards aquifer (Texas, USA and the Madison aquifer (South Dakota, USA. A one-dimensional, lumped-parameter model simulates nonstationary soil moisture changes for estimation of recharge, and a nonstationary convolution model simulates the aquifer response to this recharge. Model fit to data was 4% better for calibration periods than for validation periods. We use metrics that describe the shapes of the impulse-response functions (IRFs obtained from convolution modeling to make comparisons in the distribution of response times among sites and among aquifers. Combined principal component analysis and cluster analysis of metrics describing the shapes of the IRFs separated those sites with IRFs having a large ratio of the mean response time to the system memory from those with large skewness and kurtosis. Classification of the IRF metrics indicate that there is a range of IRF characteristics for different site types (i.e., spring flow, groundwater level, base flow within a karst system. Further, similar site types did not necessarily display similar IRFs. Results indicate that the differences existing within either aquifer are larger than the differences between the two aquifers and that the two aquifers are similar according to this classification. The use of multiple metrics to describe the IRFs provides a novel way to characterize and compare the way in which multiple sites respond to recharge. As convolution models are developed for additional aquifers, they could contribute

  6. Potential Risks of Freshwater Aquifer Contamination with Geosequestration

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Robert

    2013-09-30

    Substantial leakage of CO{sub 2} from deep geological strata to shallow potable aquifers is likely to be rare, but chemical detection of potential leakage nonetheless remains an integral component of any safe carbon capture and storage system. CO{sub 2} that infiltrates an unconfined freshwater aquifer will have an immediate impact on water chemistry by lowering pH in most cases and by altering the concentration of total dissolved solids. Chemical signatures in affected waters provide an important opportunity for early detection of leaks. In the presence of CO{sub 2}, trace elements such as Mn, Fe, and Ca can increase by an order of magnitude or more above control concentrations within 100 days. Therefore, these and other elements should be monitored along with pH as geochemical markers of potential CO{sub 2} leaks. Dissolved inorganic carbon and alkalinity can also be rapidly responsive to CO{sub 2} and are stable indicators of a leak. Importantly, such changes may be detectable long before direct changes in CO{sub 2} are observed. The experimental results also suggest that the relative severity of the impact of leaks on overlying drinking-water aquifers should be considered in the selection of CO{sub 2} sequestration sites. One primary selection criteria should be metal and metalloid availability, such as uranium and arsenic abundance, to carefully monitor chemical species that could trigger changes above maximum contaminant levels (MCLs). Overall, the risks of leakage from underground CO{sub 2} storage are real but appear to be manageable if systems are closely monitored.

  7. Risk assesment of an urban aquifer based on environmental tracers

    Directory of Open Access Journals (Sweden)

    Branka Trček

    2013-06-01

    Full Text Available Groundwater from a Pleistocene sandy-gravel aquifer is a drinking water resource for the Union brewery, located nearthe centre of Ljubljana (Slovenia. A large part of the aquifer recharge area is highly urbanized, which represents a greatrisk for the groundwater quality assurance. The groundwater dating techniques were used to study the contaminationrisk of this drinking-water resource. The application of chlorofluorocarbons (CFCs, sulphur hexafluoride (SF6 andtritium-helium-3 (3H-3He age indicator was tested, as they haven’t been used in Slovene urban areas so far. The resultsreflect that the 3H-3He dating technique is the most suitable for a groundwater age determination in the study urbanaquifer, since SF6 and particularly CFCs concentrations could be affected by the local contaminations. They indicatedthat average groundwater residence times range from 10 to 30 years. Boreholes that are more distant from the Ši{enskihrib hill are more vulnerable to contamination due to flow of young groundwater from a direction of the main aquifer,which is exposed to the urban pollution. The presented results were supplemented with chemical investigations ofgroundwater organic pollutants. An unknown trace organic pollutant with a base ion mass-to-charge ratio 147 was putinto focus. Its identification based on chromatographic separation and a mass spectrometric detection with GC-MS,LC-MS and LC-TOF MS techniques. The newly detected trace organic pollutant in sampled groundwater representstogether with the 3H and 3He data a new technique to study the flow paths and contaminant transport in the urbanaquifer in both, the lateral and vertical directions.

  8. Deep aquifer prokaryotic community responses to CO2 geosequestration

    Science.gov (United States)

    Mu, A.; Moreau, J. W.

    2015-12-01

    Little is known about potential microbial responses to supercritical CO2 (scCO2) injection into deep subsurface aquifers, a currently experimental means for mitigating atmospheric CO2 pollution being trialed at several locations around the world. One such site is the Paaratte Formation of the Otway Basin (~1400 m below surface; 60°C; 2010 psi), Australia. Microbial responses to scCO2 are important to understand as species selection may result in changes to carbon and electron flow. A key aim is to determine if biofilm may form in aquifer pore spaces and reduce aquifer permeability and storage. This study aimed to determine in situ, using 16S rRNA gene, and functional metagenomic analyses, how the microbial community in the Otway Basin geosequestration site responded to experimental injection of 150 tons of scCO2. We demonstrate an in situ sampling approach for detecting deep subsurface microbial community changes associated with geosequestration. First-order level analyses revealed a distinct shift in microbial community structure following the scCO2 injection event, with proliferation of genera Comamonas and Sphingobium. Similarly, functional profiling of the formation revealed a marked increase in biofilm-associated genes (encoding for poly-β-1,6-N-acetyl-D-glucosamine). Global analysis of the functional gene profile highlights that scCO2 injection potentially degraded the metabolism of CH4 and lipids. A significant decline in carboxydotrophic gene abundance (cooS) and an anaerobic carboxydotroph OTU (Carboxydocella), was observed in post-injection samples. The potential impacts on the flow networks of carbon and electrons to heterotrophs are discussed. Our findings yield insights for other subsurface systems, such as hydrocarbon-rich reservoirs and high-CO2 natural analogue sites.

  9. Groundwater arsenic content in Raigon Aquifer System (San Jose, Uruguay)

    International Nuclear Information System (INIS)

    As a Medical Geology research issue, an environmental arsenic risk assessment study in the most important sedimentary aquifer in southern Uruguay is presented. The Raigon Aquifer System is the most exploited in Uruguay. It has a surface extent of about 1,800 square kilometres and 10,000 inhabitants in San Jose Department, where it was studied. Agriculture and cattle breeding are the main economic activities and this aquifer is the basic support. The groundwater sampling was done on 37 water samples of PRENADER (Natural Resources Management and Irrigation Development Program) wells. Outcropping sediments of Raigon Formation and the overlying Libertad Formation were also sampled in the Kiyu region. The analyses were performed by inductively coupled plasma-optical emission spectrometry (ICP-OES) and inductively coupled plasma-mass spectrometry (ICP-MS). The results showed 80% samples with arsenic levels exceeding the 10 μg/l of WHO as limit for waters, and 11% exceeds the 20 μg/l limit of uruguayan regulation. The median, maximum and minimum water arsenic concentrations determined have been 14.24, 24.19 and 1.44 μg/l, respectively. On the other hand, nine sediment samples of Raigon and Libertad Formations in Kiyu region were analysed and yielded median, maximum and minimum arsenic concentrations of 5.03, 9.82 and 1.18 ppm, respectively. This issue leads to the supposition that the population, as well as industrial and agricultural activities, are consuming water with arsenic concentrations over the national and international maximum recommended limit.

  10. Regional Risk Assessment for climate change impacts on coastal aquifers.

    Science.gov (United States)

    Iyalomhe, F; Rizzi, J; Pasini, S; Torresan, S; Critto, A; Marcomini, A

    2015-12-15

    Coastal aquifers have been identified as particularly vulnerable to impacts on water quantity and quality due to the high density of socio-economic activities and human assets in coastal regions and to the projected rising sea levels, contributing to the process of saltwater intrusion. This paper proposes a Regional Risk Assessment (RRA) methodology integrated with a chain of numerical models to evaluate potential climate change-related impacts on coastal aquifers and linked natural and human systems (i.e., wells, river, agricultural areas, lakes, forests and semi-natural environments). The RRA methodology employs Multi Criteria Decision Analysis methods and Geographic Information Systems functionalities to integrate heterogeneous spatial data on hazard, susceptibility and risk for saltwater intrusion and groundwater level variation. The proposed approach was applied on the Esino River basin (Italy) using future climate hazard scenarios based on a chain of climate, hydrological, hydraulic and groundwater system models running at different spatial scales. Models were forced with the IPCC SRES A1B emission scenario for the period 2071-2100 over four seasons (i.e., winter, spring, summer and autumn). Results indicate that in future seasons, climate change will cause few impacts on the lower Esino River valley. Groundwater level decrease will have limited effects: agricultural areas, forests and semi-natural environments will be at risk only in a region close to the coastline which covers less than 5% of the total surface of the considered receptors; less than 3.5% of the wells will be exposed in the worst scenario. Saltwater intrusion impact in future scenarios will be restricted to a narrow region close to the coastline (only few hundred meters), and thus it is expected to have very limited effects on the Esino coastal aquifer with no consequences on the considered natural and human systems. PMID:26282744

  11. Impact of aquifer desaturation on steady-state river seepage

    Science.gov (United States)

    Morel-Seytoux, Hubert J.; Miracapillo, Cinzia; Mehl, Steffen

    2016-02-01

    Flow exchange between surface and ground water is of great importance be it for beneficial allocation and use of the water resources or for the proper exercise of water rights. That exchange can take place under a saturated or unsaturated flow regime. Which regimes occur depend on conditions in the vicinity of the interactive area. Withdrawals partially sustained by seepage may not bring about desaturation but greater amounts eventually will. The problem considered in this paper deals only with the steady-state case. It is meant as a first step toward a simple, yet accurate and physically based treatment of the transient situation. The primary purpose of the article is to provide simple criteria for determination of the initiation of desaturation in an aquifer originally in saturated hydraulic connection with a river or a recharge area. The extent of the unsaturated zone in the aquifer will increase with increasing withdrawals while at the same time the seepage rate from the river increases. However the seepage increase will stop once infiltration takes place strictly by gravity in the aquifer and is no longer opposed by the capillary rise from the water table below the riverbed. Following desaturation simple criteria are derived and simple analytical formulae provided to estimate the river seepage based on the position of the water table mound below the clogging layer and at some distance away from the river bank. They fully account for the unsaturated flow phenomena, including the existence of a drainage entry pressure. Two secondary objectives were to verify that (1) the assumption of uniform vertical flow through a clogging layer and that (2) the approximation of the water table mound below the seepage area as a flat surface were both reasonably legitimate. This approach will be especially advantageous for the implementation of the methodology in large-scale applications of integrated hydrologic models used for management.

  12. Physical and numerical modeling of seawater intrusion in coastal aquifers

    Science.gov (United States)

    Crestani, Elena; Camporese, Matteo; Salandin, Paolo

    2016-04-01

    Seawater intrusion in coastal aquifers is a worldwide problem caused, among others factors, by aquifer overexploitation, rising sea levels, and climate changes. To limit the deterioration of both surface water and groundwater quality caused by saline intrusion, in recent years many research studies have been developed to identify possible countermeasures, mainly consisting of underground barriers. In this context, physical models are fundamental to study the saltwater intrusion, since they provide benchmarks for numerical model calibrations and for the evaluation of the effectiveness of general solutions to contain the salt wedge. This work presents a laboratory experiment where seawater intrusion was reproduced in a specifically designed sand-box. The physical model, built at the University of Padova, represents the terminal part of a coastal aquifer and consists of a flume 500 cm long, 30 cm wide and 60 cm high, filled for an height of 49 cm with glass beads characterized by a d50 of 0.6 mm and a uniformity coefficient d60/d10 ≈ 1.5. The resulting porous media is homogeneous, with porosity of about 0.37 and hydraulic conductivity of about 1.3×10‑3 m/s. Upstream from the sand-box, a tank filled by freshwater provides the recharge to the aquifer. The downstream tank simulates the sea and red food dye is added to the saltwater to easily visualize the salt wedge. The volume of the downstream tank is about five times the upstream one, and, due to the small filtration discharge, salt concentration variations (i.e., water density variations) due to the incoming freshwater flow are negligible. The hydraulic gradient during the tests is constant, due to the fixed water level in the two tanks. Water levels and discharged flow rate are continuously monitored. The experiment presented here had a duration of 36 h. For the first 24 h, the saltwater wedge was let to evolve until quasi stationary condition was obtained. In the last 12 h, water withdrawal was carried out at

  13. Fluid Dynamics of Carbon Dioxide Disposal into Saline Aquifers

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Julio Enrique

    2003-12-18

    Injection of carbon dioxide (CO{sub 2}) into saline aquifers has been proposed as a means to reduce greenhouse gas emissions (geological carbon sequestration). Large-scale injection of CO{sub 2} will induce a variety of coupled physical and chemical processes, including multiphase fluid flow, fluid pressurization and changes in effective stress, solute transport, and chemical reactions between fluids and formation minerals. This work addresses some of these issues with special emphasis given to the physics of fluid flow in brine formations. An investigation of the thermophysical properties of pure carbon dioxide, water and aqueous solutions of CO{sub 2} and NaCl has been conducted. As a result, accurate representations and models for predicting the overall thermophysical behavior of the system CO{sub 2}-H{sub 2}O-NaCl are proposed and incorporated into the numerical simulator TOUGH2/ECO{sub 2}. The basic problem of CO{sub 2} injection into a radially symmetric brine aquifer is used to validate the results of TOUGH2/ECO2. The numerical simulator has been applied to more complex flow problem including the CO{sub 2} injection project at the Sleipner Vest Field in the Norwegian sector of the North Sea and the evaluation of fluid flow dynamics effects of CO{sub 2} injection into aquifers. Numerical simulation results show that the transport at Sleipner is dominated by buoyancy effects and that shale layers control vertical migration of CO{sub 2}. These results are in good qualitative agreement with time lapse surveys performed at the site. High-resolution numerical simulation experiments have been conducted to study the onset of instabilities (viscous fingering) during injection of CO{sub 2} into saline aquifers. The injection process can be classified as immiscible displacement of an aqueous phase by a less dense and less viscous gas phase. Under disposal conditions (supercritical CO{sub 2}) the viscosity of carbon dioxide can be less than the viscosity of the aqueous

  14. Managing aquifer recharge: How can isotope hydrology help?

    International Nuclear Information System (INIS)

    One of the emerging solutions to ever increasing water demand is a practice known as managed aquifer recharged (MAR) that involves diverting runoff water or recycled water into aquifers for storage and later extraction. During the last 50 years, the increased demand for freshwater has created shortages throughout the world. The projected growth in population combined with a changing climate is likely to make the situation worse. New solutions are needed to meet future water demands. One of the emerging solutions is a process known as managed aquifer recharge (MAR) that involves diverting surplus runoff water or recycled wastewater into aquifers for storage and later extraction. MAR is now practised for the combined management of groundwater and surface water in many parts of the world. While there are many potential benefits of MAR, one needs to be mindful of many potential side-effects that may arise when altering the natural water and chemical cycles within the subsurface. For example, understanding the movement and fate of injected water as well as changes to the water quality during transit through the soil and groundwater is needed. Contaminants from industry, agriculture, or municipal sources that are part of the source water supply may affect the ambient groundwater quality. The introduction of disinfection by-products, infective micro-organisms, and organic compounds with unknown health risks into groundwater supplies is a significant concern. It is paramount to understand the fate and transport of potential contaminants near MAR sites. Only from this understanding can robust and appropriate regulations be developed. Stable isotopes of water and conservative ions are used as 'fingerprints' that can trace movement and fate of water. Also, dating with tritium and its daughter, 3 He, and deliberate tracer experiments are used to estimate water residence time within the subsurface. This knowledge is needed to established hydraulic connections and travel times

  15. Managed Aquifer Recharge in Italy: present and prospects.

    Science.gov (United States)

    Rossetto, Rudy

    2015-04-01

    On October the 3rd 2014, a one-day Workshop on Managed Aquifer Recharge (MAR) experiences in Italy took place at the GEOFLUID fair in Piacenza. It was organized within the framework of the EIP AG 128 - MAR Solutions - Managed Aquifer Recharge Strategies and Actions and the EU FPVII MARSOL. The event aimed at showcasing present experiences on MAR in Italy while at the same time starting a network among all the Institutions involved. In this contribution, we discuss the state of MAR application in Italy and summarize the outcomes of that event. In Italy aquifer recharge is traditionally applied unintentionally, by increasing riverbank filtration or because of excess irrigation. A certain interest for artificial recharge of aquifers arose at the end of the '70s and the beginning of the '80s and tests have been carried out in Tuscany, Veneto and Friuli Venezia Giulia. During the last years some projects on aquifer recharge were co-financed by the European Commission mainly through the LIFE program. Nearly all of them use the terminology of artificial recharge instead of MAR. They are: - TRUST (Tool for regional - scale assessment of groundwater storage improvement in adaptation to climate change, LIFE07 ENV/IT/000475; Marsala 2014); - AQUOR (Implementation of a water saving and artificial recharging participated strategy for the quantitative groundwater layer rebalance of the upper Vicenza's plain - LIFE 2010 ENV/IT/380; Mezzalira et al. 2014); - WARBO (Water re-born - artificial recharge: innovative technologies for the sustainable management of water resources, LIFE10 ENV/IT/000394; 2014). While the TRUST project dealt in general with aquifer recharge, AQUOR and WARBO focused essentially on small scale demonstration plants. Within the EU FPVII-ENV-2013 MARSOL project (Demonstrating Managed Aquifer Recharge as a Solution to Water Scarcity and Drought; 2014), a dedicated monitoring and decision support system is under development to manage recharge at a large scale

  16. Groundwater Availability of the Central Valley Aquifer, California

    Science.gov (United States)

    Faunt, Claudia C.

    2009-01-01

    California's Central Valley covers about 20,000 square miles and is one of the most productive agricultural regions in the world. More than 250 different crops are grown in the Central Valley with an estimated value of $17 billion per year. This irrigated agriculture relies heavily on surface-water diversions and groundwater pumpage. Approximately one-sixth of the Nation's irrigated land is in the Central Valley, and about one-fifth of the Nation's groundwater demand is supplied from its aquifers. The Central Valley also is rapidly becoming an important area for California's expanding urban population. Since 1980, the population of the Central Valley has nearly doubled from 2 million to 3.8 million people. The Census Bureau projects that the Central Valley's population will increase to 6 million people by 2020. This surge in population has increased the competition for water resources within the Central Valley and statewide, which likely will be exacerbated by anticipated reductions in deliveries of Colorado River water to southern California. In response to this competition for water, a number of water-related issues have gained prominence: conservation of agricultural land, conjunctive use, artificial recharge, hydrologic implications of land-use change, and effects of climate variability. To provide information to stakeholders addressing these issues, the USGS Groundwater Resources Program made a detailed assessment of groundwater availability of the Central Valley aquifer system, that includes: (1) the present status of groundwater resources; (2) how these resources have changed over time; and (3) tools to assess system responses to stresses from future human uses and climate variability and change. This effort builds on previous investigations, such as the USGS Central Valley Regional Aquifer System and Analysis (CV-RASA) project and several other groundwater studies in the Valley completed by Federal, State and local agencies at differing scales. The

  17. Hydraulic characterization of aquifers by thermal response testing

    Science.gov (United States)

    Wagner, Valentin; Blum, Philipp; Bayer, Peter

    2014-05-01

    Temperature as a major physical quantity of the subsurface, and naturally occurring thermal anomalies are recognized as promising passive tracers to characterize the subsurface. Accelerated by the increasing popularity of geothermal energy, also active thermal field experiments have gained interest in hydrogeology. Such experiments involve artificial local ground heating or cooling. Among these, the thermal response test (TRT) is one of the most established field investigation techniques in shallow geothermal applications. It is a common method to investigate important subsurface heat transport parameters to design sustainable ground-source heat pump (GSHP) systems. During the test, the borehole heat exchanger (BHE) is heated up with a defined amount of energy by circulating a heat carrier fluid. By comparing temperature change between BHE inlet and outlet, the ability of the BHE to transfer heat or cold to the ambient ground is assessed. However, standard interpretation does not provide any insight into the governing processes of in-situ heat transfer. We utilize a groundwater advection sensitive TRT evaluation approach based on the analytical moving line source equation. It is shown that the TRT as a classical geothermal field test can also be used as a hydrogeological field test. Our approach benefits from the fact that thermal properties, such as thermal conductivity, of natural aquifers typically are much less variable than hydraulic properties, such as hydraulic conductivity. It is possible to determine a relatively small hydraulic conductivity range with our TRT evaluation approach, given realistic ranges for thermal conductivity, volumetric heat capacity, thermal dispersivity and thermal borehole resistance. The method is successfully tested on a large-scale geothermal laboratory experiment (9 m × 6 m × 4.5 m) and with a commercially performed TRT in the field scale. The laboratory experiment consists of a layered artificial aquifer, which is penetrated

  18. Methodology for rapid assessment of aquifer recharge areas

    Directory of Open Access Journals (Sweden)

    Vitor Vieira Vasconcelos

    2013-06-01

    Full Text Available The environmental tools of local appliance, such as surveillance and permits of deforestations and water use, environmentalimpact assessments of local scale, and delimitation of preservation areas, demand customized methodologies to deal withhydrogeological issues. In this study, a structured one for rapid environmental assessment aiming at recharge of aquiferssafety was presented. This comprises qualitative and quantitative evaluations by means of textual and cartographicaldescriptions, complemented by weighted spreadsheets for rapid assessment. Applications in case studies took place in sitesselected in the Paracatu River Basin. The results showed a positive potential for knowledge and protection of aquifers inmicro-watersheds.

  19. A Microbiological Water Quality Evaluation of Ganges River Deltaic Aquifers

    Science.gov (United States)

    Yerby, C. J.; Gragg, S. E.; Page, J.; Leavens, J.; Bhattacharya, P.; Harrington, J.; Datta, S.

    2014-12-01

    Substantial natural contamination from trace elements (like arsenic) and pathogens make Ganges Deltaic aquifers an area of utmost concern. Following millions of cases of chronic arsenic poisoning from the groundwaters of the region, numerous residents are still knowingly ingesting water from shallow to intermediate accessible depth drinking water wells. Added to the calamity of arsenic is the prevalence of pathogenic bacteria in these waters. The increasing frequency of gastroenteritis signifies the need to quantify the magnitude and extensiveness of health degrading agents--bacterial pathogens (i.e. Salmonella) and non-pathogens (i.e. Enterobacteriaceae) --within the water supply in accessible Gangetic aquifers. To assess the dissolved microbiological quality in the region, present study sampling locations are along defined piezometer nests in an area in SE Asia (Bangladesh). Every nest contains samples from wells at varying depths covering shallow to deep aquifers. To date, 17 of the 76 water samples were analyzed for Salmonella, generic Escherichia coli (E. coli) and coliforms. Briefly, samples were plated in duplicate onto E. coli/Coliform petrifilm and incubated at 370C for 48 hours. Next, each sample was enriched in buffered peptone water and incubated at 370C for 18 hours. Bacterial DNA was extracted and amplified using a qPCR machine. Amplification plots were analyzed to determine presence/absence of microorganisms. All water samples (n=~76) are analyzed for Salmonella, Escherichia coli O157:H7, Listeria spp. and Shigella. Pathogen populations of PCR-positive water samples are enumerated using the agar direct plate method. Non-pathogenic bacterial indicator organisms (i.e. Enterobacteriaceae) will also be enumerated. Over the course of the experiment, we hypothesize that shallower wells will 1)have a higher pathogen prevalence and 2)harbor pathogens and nonpathogens at higher concentrations. While the 17 samples analyzed to date were negative for Salmonella

  20. Mineralization Of PAHs In Coal-Tar Impacted Aquifer Sediments And Associated Microbial Community Structure Investigated With FISH

    Science.gov (United States)

    The microbial community structure and mineralization of polycyclic aromatic hydrocarbons (PAHs) in a coal-tar contaminated aquifer were investigated spatially using fluorescence in situ hybridization (FISH) and in laboratory-scale incubations of the aquifer sediments. DAPI-detect...

  1. L'aquifère du bassin de la Mamora, Maroc: geometrie et ecoulements souterrainsThe aquifer of the Mamora Basin, Morocco: geometry and groundwater flow

    Science.gov (United States)

    Zouhri, L.

    2001-05-01

    The Mamora aquifer, in the northern Moroccan Meseta, constitutes the main regional water resource. Its impermeable basement is mostly composed of blue marls. The lithostratigraphy of the basin aquifer is characterised by a sequence of sandstones, sandy limestones, conglomerates and sandy clays. The structure of the basement of the Mamora aquifer, deduced from electrical resistivity measurements, allowed the hydrogeological behaviour of the reservoir, and the direction of the groundwater flow, to be established. The combination of the lithological, morphological, piezometric, geophysical and structural investigations revealed a northward thickening of the substrate with groundwater flow towards the Rharb (to the north) and towards the Atlantic Ocean (northwest). This 'multicriteria' approach enabled a structural model to be defined, which correlated well with the aquifer geometry and the groundwater flow. The variability of the hydrogeological units, and the northward thickening of the sedimentary facies, were controlled by northeast-southwest orientated faults, which affect their impermeability.

  2. Geodatabase of the datasets used to represent the four aquifer subunits of the Cambrian-Ordovician aquifer system, Illinois, Iowa, Michigan, Minnesota, and Wisconsin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This geodatabase includes spatial datasets that represent the Cambrian-Ordovician aquifer system in the States of Wisconsin, Michigan, Minnesota, Iowa, and...

  3. Hydrogeology - AQUIFERS_BEDROCK_USGS_IN: Bedrock Aquifer Systems in Indiana (United States Geological Survey, 1:500,000, Polygon Shapefile)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Four types of bedrock aquifers in 12 water-management basins identified by the Indiana Natural Resources Commission (INRC) in Indiana were identified by the USGS in...

  4. Hydrogeology - AQUIFERS_UNCONSOLIDATED_USGS_IN: Unconsolidated Aquifer Systems in Indiana (United States Geological Survey, 1:500,000, Polygon Shapefile)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Five types of unconsolidated aquifers in 12 water-management basins identified by the Indiana Natural Resources Commission (INRC) in Indiana were identified by the...

  5. Estimation of transit times in a Karst Aquifer system using environmental tracers: Application on the Jeita Aquifer system-Lebanon.

    Science.gov (United States)

    Doummar, Joanna; Hamdan, Ahmad

    2016-04-01

    Estimating transit times is essential for the assessment of aquifer vulnerability to contaminants. Groundwater in karst aquifer is assumed to be relatively young due to fast preferential pathways; slow flow components are present in water stored in the fissured matrix. Furthermore, transit times are site specific as they depend on recharge rates, temperatures, elevation, and flow media; saturated and unsaturated zones. These differences create significant variation in the groundwater age in karst systems as the water sampled will be a mix of different water that has been transported through different flow pathways (fissured matrix and conduits). Several methods can be applied to estimate water transit time of an aquifer such as artificial tracers, which provide an estimate for fast flow velocities. In this study, groundwater residence times in the Jeita spring aquifer (Lebanon) were estimated using several environmental tracers such as Chlorofluorocarbons (CFCs), Sulfur Hexafluoride (SF6), Helium-Tritium (3H, 3H- 3He). Additional stable isotope and major ion analysis was performed to characterize water types. Groundwater samples were collected from six different wells in the Jeita catchment area (Jurassic Kesrouane aquifer) as well as from the spring and cave itself. The results are reproducible for the Tritium-Helium method, unlike for the CFC/SF6 methods that yielded poor results due to sampling problems. Tritium concentrations in all groundwater samples show nearly the same concentration (~2.73 TU) except for one sample with relatively lower tritium concentration (~2.26 TU). Ages ranging from 0.07 ± 0.07 years to 23.59 ± 0.00 years were obtained. The youngest age is attributed to the spring/ cave while the oldest ages were obtained in wells tapping the fissured matrix. Neon in these samples showed considerable variations and high delta Ne in some samples indicating high excess air. Four (4) samples showed extreme excess air (Delta-Ne is greater than 70 %) and

  6. Characterization of aquifer heterogeneity using Cyclostratigraphy and geophysical methods in the upper part of the Karstic Biscayne Aquifer, Southeastern Florida

    Science.gov (United States)

    Cunningham, Kevin J.; Carlson, Janine L.; Wingard, G. Lynn; Robinson, Edward; Wacker, Michael A.

    2004-01-01

    This report identifies and characterizes candidate ground-water flow zones in the upper part of the shallow, eogenetic karst limestone of the Biscayne aquifer in the Lake Belt area of north-central Miami-Dade County using cyclostratigraphy, ground-penetrating radar (GPR), borehole geophysical logs, and continuously drilled cores. About 60 miles of GPR profiles were used to calculate depths to shallow geologic contacts and hydrogeologic units, image karst features, and produce qualitative views of the porosity distribution. Descriptions of the lithology, rock fabrics, and cyclostratigraphy, and interpretation of depositional environments of 50 test coreholes were linked to the geophysical interpretations to provide an accurate hydrogeologic framework. Molluscan and benthic foraminiferal paleontologic constraints guided interpretation of depositional environments represented by rockfabric facies. Digital borehole images were used to characterize and quantify large-scale vuggy porosity. Preliminary heat-pulse flowmeter data were coupled with the digital borehole image data to identify candidate ground-water flow zones. Combined results show that the porosity and permeability of the karst limestone of the Biscayne aquifer have a highly heterogeneous and anisotropic distribution that is mostly related to secondary porosity overprinting vertical stacking of rock-fabric facies within high-frequency cycles (HFCs). This distribution of porosity produces a dual-porosity system consisting of diffuse-carbonate and conduit flow zones. The nonuniform ground-water flow in the upper part of the Biscayne aquifer is mostly localized through secondary permeability, the result of solution-enlarged carbonate grains, depositional textures, bedding planes, cracks, root molds, and paleokarst surfaces. Many of the resulting pore types are classified as touching vugs. GPR, borehole geophysical logs, and whole-core analyses show that there is an empirical relation between formation porosity

  7. Regional assessment of aquifers for thermal energy storage. Volume 1. Regions 1 through 6

    Energy Technology Data Exchange (ETDEWEB)

    1981-06-01

    This volume contains information on the geologic and hydrologic framework, major aquifers, aquifers which are suitable and unsuitable for annual thermal energy storage (ATES) and the ATES potential of the following regions of the US: the Western Mountains; Alluvial Basins; Columbia LAVA Plateau; Colorado Plateau; High Plains; and Glaciated Central Region. (LCL)

  8. Carbonate Chemistry and Isotope Characteristics of Groundwater of Ljubljansko Polje and Ljubljansko Barje Aquifers in Slovenia

    Science.gov (United States)

    2013-01-01

    Ljubljansko polje and Ljubljansko Barje aquifers are the main groundwater resources for the needs of Ljubljana, the capital of Slovenia. Carbonate chemistry and isotope analysis of the groundwater were performed to acquire new hydrogeological data, which should serve as a base for improvement of hydrogeological conceptual models of both aquifers. A total of 138 groundwater samples were collected at 69 sampling locations from both aquifers. Major carbonate ions and the stable isotope of oxygen were used to identify differences in the recharging areas of aquifers. Four groups of groundwater were identified: (1) Ljubljansko polje aquifer, with higher Ca2+values, as limestone predominates in its recharge area, (2) northern part of Ljubljansko Barje aquifer, with prevailing dolomite in its recharge area, (3) central part of Ljubljansko Barje aquifer, which lies below surface cover of impermeable clay and is poor in carbonate, and (4) Brest and Iški vršaj aquifer in the southern part of Ljubljansko Barje with higher Mg2+ in groundwater and dolomite prevailing in its recharge area. The radioactive isotope tritium was also used to estimate the age of groundwater. Sampled groundwater is recent with tritium activity between 4 and 8 TU and residence time of up to 10 years. PMID:24453928

  9. Using Genetic Algorithm and MODFLOW to Characterize Aquifer System of Northwest Florida (Published Proceedings)

    Science.gov (United States)

    By integrating Genetic Algorithm and MODFLOW2005, an optimizing tool is developed to characterize the aquifer system of Region II, Northwest Florida. The history and the newest available observation data of the aquifer system is fitted automatically by using the numerical model c...

  10. Using Genetic Algorithm and MODFLOW to Characterize Aquifer System of Northwest Florida

    Science.gov (United States)

    By integrating Genetic Algorithm and MODFLOW2005, an optimizing tool is developed to characterize the aquifer system of Region II, Northwest Florida. The history and the newest available observation data of the aquifer system is fitted automatically by using the numerical model c...

  11. Use of stable isotope-labeled Escherichia coli as a tracer in karst aquifers

    Science.gov (United States)

    Bacterial contamination of karst aquifers is a large concern across the globe, yet bacterial transport in karst aquifers is not currently well understood. Groundwater tracers typically used in karst systems include fluorescent dyes and latex microspheres. Not only can these tracers can be cost-prohi...

  12. QTRACER PROGRAM FOR TRACER-BREAKTHROUGH CURVE ANALYSIS FOR KARST AND FRACTURED-ROCK AQUIFERS

    Science.gov (United States)

    Tracer tests are generally regarded as being the most reliable and efficient means of gathering subsurface hydraulic information. This is true for all types of aquifers, but especially so for karst and fractured-rock aquifers. Qualitative tracing tests have been conventionally em...

  13. 78 FR 19261 - Safe Drinking Water Act Sole Source Aquifer Program; Designation of Bainbridge Island, Washington...

    Science.gov (United States)

    2013-03-29

    ...Notice is hereby given that pursuant to Section 1424(e) of the Safe Drinking Water Act, the Administrator of the U.S. Environmental Protection Agency (EPA) has determined that the Bainbridge Island Aquifer System located in Kitsap County, Washington is the sole or principle source of drinking water for the citizens of Bainbridge Island and that this aquifer system, if contaminated would create......

  14. Palaeoclimatic trends deduced from the hydrochemistry of a Triassic sandstone aquifer, U.K

    International Nuclear Information System (INIS)

    A detailed geochemical study (elemental, isotopic and dissolved inert gases) of unconfined and confined sections of the Triassic non-marine sandstone aquifer in Eastern England has been undertaken. Aspects of the recharge history of this aquifer over the past 40 000 years are revealed by examination of the data. (orig./HK)

  15. Estimation of hydraulic parameters in a complex porous aquifer system using geoelectrical methods.

    Science.gov (United States)

    Kazakis, N; Vargemezis, G; Voudouris, K S

    2016-04-15

    Geoelectrical methods have been widely used for the estimation of aquifer hydraulic properties. In this study, geoelectrical methods were applied in a lithologically and hydrochemically complex porous aquifer to estimate its porosity, hydraulic conductivity and transmissivity. For this purpose, the electrical resistivity of the aquifer as well as the electrical conductivity of the groundwater was measured in 37 sites and wells. Initially, the Archie's law was used to generate sets of cementation factor (m) and alpha (α) parameter from which the mode values of α=0.98 and m=1.75 are representative of the studied aquifer. The transmissivity of the aquifer varies from 5.1×10(-3) to 3.1×10(-5)m(2)/s, whereas the mean value of its porosity is 0.45. The hydraulic conductivity of the aquifer which was calculated according to Archie's law varies from 2.08×10(-6) to 6.84×10(-5)m/s and is strongly correlated with the pumping test's hydraulic conductivity. In contrast, the hydraulic conductivity which was calculated using Dar-Zarrouk parameters presents lower correlation with the pumping test's hydraulic conductivity. Furthermore, a relation between aquifer resistivity and hydraulic conductivity was established for the studied aquifer to enable the estimation of these parameters in sites lacking data. PMID:26849338

  16. Regional assessment of aquifers for thermal-energy storage. Volume 2. Regions 7 through 12

    Energy Technology Data Exchange (ETDEWEB)

    1981-06-01

    This volume contains information on the geologic and hydrologic framework, major aquifers, aquifers which are suitable and unsuitable for annual thermal energy storage (ATES) and the ATES potential of the following regions of the US: Unglaciated Central Region; Glaciated Appalachians, Unglaciated Appalachians; Coastal Plain; Hawaii; and Alaska. (LCL)

  17. Estimation of hydraulic parameters in a complex porous aquifer system using geoelectrical methods.

    Science.gov (United States)

    Kazakis, N; Vargemezis, G; Voudouris, K S

    2016-04-15

    Geoelectrical methods have been widely used for the estimation of aquifer hydraulic properties. In this study, geoelectrical methods were applied in a lithologically and hydrochemically complex porous aquifer to estimate its porosity, hydraulic conductivity and transmissivity. For this purpose, the electrical resistivity of the aquifer as well as the electrical conductivity of the groundwater was measured in 37 sites and wells. Initially, the Archie's law was used to generate sets of cementation factor (m) and alpha (α) parameter from which the mode values of α=0.98 and m=1.75 are representative of the studied aquifer. The transmissivity of the aquifer varies from 5.1×10(-3) to 3.1×10(-5)m(2)/s, whereas the mean value of its porosity is 0.45. The hydraulic conductivity of the aquifer which was calculated according to Archie's law varies from 2.08×10(-6) to 6.84×10(-5)m/s and is strongly correlated with the pumping test's hydraulic conductivity. In contrast, the hydraulic conductivity which was calculated using Dar-Zarrouk parameters presents lower correlation with the pumping test's hydraulic conductivity. Furthermore, a relation between aquifer resistivity and hydraulic conductivity was established for the studied aquifer to enable the estimation of these parameters in sites lacking data.

  18. Carbonate Chemistry and Isotope Characteristics of Groundwater of Ljubljansko Polje and Ljubljansko Barje Aquifers in Slovenia

    Directory of Open Access Journals (Sweden)

    Sonja Cerar

    2013-01-01

    Full Text Available Ljubljansko polje and Ljubljansko Barje aquifers are the main groundwater resources for the needs of Ljubljana, the capital of Slovenia. Carbonate chemistry and isotope analysis of the groundwater were performed to acquire new hydrogeological data, which should serve as a base for improvement of hydrogeological conceptual models of both aquifers. A total of 138 groundwater samples were collected at 69 sampling locations from both aquifers. Major carbonate ions and the stable isotope of oxygen were used to identify differences in the recharging areas of aquifers. Four groups of groundwater were identified: (1 Ljubljansko polje aquifer, with higher Ca2+ values, as limestone predominates in its recharge area, (2 northern part of Ljubljansko Barje aquifer, with prevailing dolomite in its recharge area, (3 central part of Ljubljansko Barje aquifer, which lies below surface cover of impermeable clay and is poor in carbonate, and (4 Brest and Iški vršaj aquifer in the southern part of Ljubljansko Barje with higher Mg2+ in groundwater and dolomite prevailing in its recharge area. The radioactive isotope tritium was also used to estimate the age of groundwater. Sampled groundwater is recent with tritium activity between 4 and 8 TU and residence time of up to 10 years.

  19. TWO-DIMENSIONAL MODELING OF AQUIFER REMEDIATION INFLUENCED BY SORPTION NONEQUILIBRIUM AND HYDRAULIC CONDUCTIVITY HETEROGENEITY

    Science.gov (United States)

    A computational model was developed to simulate aquifer remediation by pump and treat for a confined, perfectly stratified aquifer. A split-operator finite element numerical technique was utilized to incorporate flow field heterogeneity and nonequilibrium sorption into a two-dime...

  20. Adsorption/desorption of phosphorus on limestone from the Biscayne Aquifer under freshwater and seawater conditions.

    Science.gov (United States)

    Areas of seawater intrusion are known geochemically active regions particularly in limestone aquifers, where carbonate mineral dissolution and ion exchange reactions are important. Both of these processes can lead to a release of phosphorus from the aquifer matrix to the groundwater as seawater int...

  1. Salt water intrusion in aquifers of the south oriental coastal zones of Sicily

    International Nuclear Information System (INIS)

    The study of coastal aquifers deserves special attention in research and management of underground water resources. In this work we study the increase of salinity in coastal aquifers of south east Sicily, from Syracuse to Donnalucata, an area subject to intense overexploitation. Results of analyses of water samples collected in 2002-2004 in wells, springs and submarine springs are presented. (author)

  2. Solute geochemistry of the Snake River Plain regional aquifer system, Idaho and eastern Oregon

    International Nuclear Information System (INIS)

    Three geochemical methods were used to determine chemical reactions that control solute concentrations in the Snake River Plain regional aquifer system: (1) calculation of a regional solute balance within the aquifer and of mineralogy in the aquifer framework to identify solute reactions, (2) comparison of thermodynamic mineral saturation indices with plausible solute reactions, and (3) comparison of stable isotope ratios of the groundwater with those in the aquifer framework. The geothermal groundwater system underlying the main aquifer system was examined by calculating thermodynamic mineral saturation indices, stable isotope ratios of geothermal water, geothermometry, and radiocarbon dating. Water budgets, hydrologic arguments, and isotopic analyses for the eastern Snake River Plain aquifer system demonstrate that most, if not all, water is of local meteoric and not juvenile or formation origin. Solute balance, isotopic, mineralogic, and thermodynamic arguments suggest that about 20% of the solutes are derived from reactions with rocks forming the aquifer framework. Reactions controlling solutes in the western Snake river basin are believed to be similar to those in the eastern basin but the regional geothermal system that underlies the Snake river Plain contains total dissolved solids similar to those in the overlying Snake River Plain aquifer system but contains higher concentrations of sodium, bicarbonate, silica, fluoride, sulfate, chloride, arsenic, boron, and lithium, and lower concentrations of calcium, magnesium, and hydrogen. 132 refs., 30 figs., 27 tabs

  3. A Columbia River Basalt Group Aquifer in Sustained Drought: Insight from Geophysical Methods

    Directory of Open Access Journals (Sweden)

    Mark W. Piersol

    2015-07-01

    Full Text Available Aquifers within the Columbia River Basalt Group (CRBG provide a critical water supply throughout much of the Pacific Northwest of the United States. Increased pumping has resulted in water level declines in this region. Recharge into this aquifer system is generally not well understood. Recent suggestions of probable decades-long droughts in the 21st century add to this problem. We show that geophysical methods can provide useful parameters for improved modeling of aquifers in a primary CRBG aquifer located on the eastern edge of the Columbia Plateau. Groundwater models depend in part on the area, thickness, porosity, storativity, and nature of confinement of this aquifer, most of which are poorly constrained by existing well information and previous stress tests. We have made use of surface gravity measurements, borehole gravity measurements, barometric efficiency estimates, earth tidal response, and earthquake seismology observations to constrain these parameters. We show that the aquifer, despite its persistent drawdown, receives a great deal of recharge annually. Much of the recharge to the aquifer is due to leakage from overlying flows, ultimately tied to precipitation, an important result for future aquifer management in times of sustained drought.

  4. Analytical solutions for whirling groundwater flow in two-dimensional heterogeneous anisotropic aquifers

    NARCIS (Netherlands)

    Hemker, K.; Bakker, M.

    2006-01-01

    Analytical solutions are derived for steady state groundwater flow in a heterogeneous, anisotropic, semiconfined aquifer. The aquifer consists of a number of horizontal layers, while each layer consists of a number of homogeneous cells with different hydraulic conductivity tensors. An exact solution

  5. Hydrogeology and aquifer test on the San Andres-Glorieta Aquifer on the southwest part of the Zuni Indian Reservation, Cibola County, New Mexico

    Science.gov (United States)

    Crouch, T.M.

    1994-01-01

    A large-yield aquifer test of the confined San Andres-Glorieta aquifer was conducted in 1988 to estimate aquifer properties and evaluate the potential effects of large-scale development on the aquifer by pumping from a cave-fracture system on the southwest part of the Zuni Indian Reservation. The San Andres-Glorieta aquifer underlies the reservation and in much of the area is the only aquifer capable of yielding large volumes of water. Two observation wells were drilled 1.2 and 2.7 miles from the pumped well. Water-level responses were recorded at distances from 179 feet to about 5 miles from the pumped well at these and other wells and at Rainbow Spring. Water levels declined at all observation wells and Rainbow Spring in response to pumping for more than 10 days at about 2,580 gallons per minute. Drawdown after 9 days varied from about 4 feet at the pumped well to about 0.2 foot at the most distant observation well and Rainbow Spring. If pumping continued at the average rate as the first 9 days of the test, 2,540 gallons per minute, and aquifer response remained constant, Rainbow Spring would have nearly 2 feet of drawdown after 30 years, and probably would be accompanied by a reduction in springflow of about 65 percent, to about 210 gallons per minute. Water quality remained generally unchanged throughout the aquifer test and is practically the same as that of samples collected at well ZS-1 in 1984 and Rainbow Spring in 1979.

  6. Assessing and modelling hard rock aquifer recharge based on complementary methodologies : a case study in the Gabbros of Beja Aquifer System, South Portugal

    OpenAIRE

    Paralta, Eduardo; Oliveira, M.

    2005-01-01

    The "Gabbros of Beja" Aquifer System extends for approximately 350 km2 and is one of the most important reservoirs of groundwater in the context of hard rocks aquifers of South Portugal (Alentejo Region). The average annual rainfall in the area is about 500 to 600 mm. Groundwater resources are used for public supply over 3 councils and irrigation. During drought cycles consumption increases and pumping rates decrease with correspondent management difficulties and conflicts between private ...

  7. Hydrogeology of the North Coast Limestone aquifer system of Puerto Rico

    Science.gov (United States)

    Rodríguez-Martínez, Jesús

    1995-01-01

    The North Coast Limestone aquifer system of Puerto Rico is composed of three regional hydrogeologic units: an upper aquifer that contains an underlying saltwater zone near the coast, a middle confining unit, and a lower aquifer. The upper aquifer is unconfined, except in coastal areas where it is locally confined by fine-grained surficial deposits. The upper aquifer is mostly absent in the Rio Piedras area of northeastern Puerto Rico. The confining unit is composed of calcareous claystone, marl, chalky and silicified limestone, and locally clayey fine-grained sandstone. Test hole data indicate that the confining unit is locally leaky in the San Juan metropolitan area. An artesian zone of limited areal extent exists within the middle confining unit, in the central part of the study area. The lower aquifer mostly contains ground water under confined conditions except in the outcrop areas, where it is unconfined. The lower aquifer is thickest and most transmissive in the north-central part of the study area. Water in the lower aquifer is fresh throughout much of the area, but is brackish in some areas near San Juan and Guaynabo. West of the Rio Grande de Arecibo, the extent of the lower aquifer is uncertain. Data are insufficient to determine whether or not the existing multiple water-bearing units in this area are an extension of the more productive lower aquifer in the Manati to Arecibo area. Zones of moderate permeability exist within small lenses of volcanic conglomerate and sandstone of the San Sebastian Formation, but in general this formation is not a productive aquifer. Transmissivity values for the upper aquifer range from 200 to more than 280,000 feet squared per day. The transmissivity values for the upper aquifer generally are highest in the area between the Rio de la Plata and Rio Grande de Arecibo, where transmissivity values have been reported to exceed 100,000 feet squared per day in six locations. Transmissivity estimates for the lower aquifer are

  8. Fluoride in the Serra Geral Aquifer System: Source Evaluation Using Stable Isotopes and Principal Component Analysis

    Directory of Open Access Journals (Sweden)

    Arthur Schmidt Nanni

    2013-01-01

    Full Text Available Groundwater with anomalous fluoride content and water mixture patterns were studied in the fractured Serra Geral Aquifer System, a basaltic to rhyolitic geological unit, using a principal component analysis interpretation of groundwater chemical data from 309 deep wells distributed in the Rio Grande do Sul State, Southern Brazil. A four-component model that explains 81% of the total variance in the Principal Component Analysis is suggested. Six hydrochemical groups were identified. δ18O and δ2H were analyzed in 28 Serra Geral Aquifer System samples in order to identify stable isotopes patterns and make comparisons with data from the Guarani Aquifer System and meteoric waters. The results demonstrated a complex water mixture between the Serra Geral Aquifer System and the Guarani Aquifer System, with meteoric recharge and ascending water infiltration through an intensive tectonic fracturing.

  9. Impact of climate change on groundwater in a confined Mediterranean aquifer

    Directory of Open Access Journals (Sweden)

    Y. Caballero

    2015-10-01

    Full Text Available This paper presents an inverse modeling method based on wavelet analysis, devoted to assessment of the impacts of climate change on the groundwater resources of a confined coastal multi-layer aquifer, located in the south of France (Pyrénées-Orientales. The hydraulic behavior of the aquifer is described based on the results of a model calibrated to simulate the groundwater dynamics observed on two representative piezometers. The relative contributions of the climate and pumping forcings to the piezometric variations are quantified. The results illustrate in quantitative terms the dominant influence of pumping on the temporal variations of the hydraulic head of the aquifer. Based on this specific behavior simulation, we show the moderate vulnerability of such confined aquifers to climate change. Some insights regarding pumping strategies for confined coastal aquifers that could contribute towards preserving their good status in future are also provided.

  10. Long term dynamic isotope and hydrochemical changes in the deep aquifer of 'Complexe terminal' (Southern Tunisia)

    International Nuclear Information System (INIS)

    It is common to consider that spatial scatter of isotopic composition within fossil aquifers is more significant than variations in time. These observations must be treated with some reserve, since the time of observations is often too short for detecting meaningful changes taking into account the slow rate of water movement in these aquifers. In the other hand, it is also noticeable that intensive uses of groundwater can bring about important changes in aquifer characteristics (flow rate, flow line, ...). In this paper, based on five (5) sampling campaign for chemical and isotopic studies of the 'Complexe terminal' aquifer in the Djerid basin and its borders, we intend to quantify content variation rates for 2H and 18O according to the exploitation of the aquifer since 1972, date of the first sampling campaign. (author)

  11. Longitudinal dispersion with time-dependent source concentration in semi-infinite aquifer

    Indian Academy of Sciences (India)

    Mritunjay Kumar Singh; Nav Kumar Mahato; Premlata Singh

    2008-12-01

    An analytical solution is obtained to predict the contaminant concentration along unsteady ground-water flow in semi-in finite aquifer. Initially,the aquifer is not supposed to be solute free ,i.e.,aquifer is not clean.A time-dependent source concentration is considered at the origin of the aquifer and at the other end of the aquifer, it is supposed to be zero. The time-dependent forms of unsteady velocities are considered in which one such form ,i.e., sinusoidal form represents the seasonal pattern in a year in tropical regions. The Laplace Transformation Technique (LTT)is used to get an analytical solution and a graphical representation is made through MATLAB.

  12. Evaluation of karstic aquifers contribution to streams by the statistical analysis of recession curves

    Indian Academy of Sciences (India)

    A Cem Koc

    2008-02-01

    Karstic aquifers significantly contribute to streams in most of Turkey’s river basins, so studies on karst water resources have great importance for Turkey. Karstic aquifer contributions are generally emerging at several locations near the river bed and are not readily measured by direct hydrometric methods. In this study, the extent of karstic aquifer contributions to a stream will be investigated by the statistical analysis of recession coefficients of recession curves. Six stream gauging stations on different streams in the western Mediterranean region of Turkey are selected. Recession periods of the streams are simulated by exponential and quadratic recession curve models. Recession coefficient series of the stream gauging stations are statistically investigated. The comparison of various statistical parameters shows that the recession coefficient series are fairly related to the karstic aquifer contributions. Especially, the measure of spread parameters, standard deviation and interquartile range of recession coefficient series are related to the extent of the karstic aquifer contributions to streams.

  13. Predicting aquifer response time for application in catchment modeling.

    Science.gov (United States)

    Walker, Glen R; Gilfedder, Mat; Dawes, Warrick R; Rassam, David W

    2015-01-01

    It is well established that changes in catchment land use can lead to significant impacts on water resources. Where land-use changes increase evapotranspiration there is a resultant decrease in groundwater recharge, which in turn decreases groundwater discharge to streams. The response time of changes in groundwater discharge to a change in recharge is a key aspect of predicting impacts of land-use change on catchment water yield. Predicting these impacts across the large catchments relevant to water resource planning can require the estimation of groundwater response times from hundreds of aquifers. At this scale, detailed site-specific measured data are often absent, and available spatial data are limited. While numerical models can be applied, there is little advantage if there are no detailed data to parameterize them. Simple analytical methods are useful in this situation, as they allow the variability in groundwater response to be incorporated into catchment hydrological models, with minimal modeling overhead. This paper describes an analytical model which has been developed to capture some of the features of real, sloping aquifer systems. The derived groundwater response timescale can be used to parameterize a groundwater discharge function, allowing groundwater response to be predicted in relation to different broad catchment characteristics at a level of complexity which matches the available data. The results from the analytical model are compared to published field data and numerical model results, and provide an approach with broad application to inform water resource planning in other large, data-scarce catchments. PMID:24842053

  14. Modeling cross-hole slug tests in an unconfined aquifer

    Science.gov (United States)

    Malama, Bwalya; Kuhlman, Kristopher L.; Brauchler, Ralf; Bayer, Peter

    2016-09-01

    A modified version of a published slug test model for unconfined aquifers is applied to cross-hole slug test data collected in field tests conducted at the Widen site in Switzerland. The model accounts for water-table effects using the linearized kinematic condition. The model also accounts for inertial effects in source and observation wells. The primary objective of this work is to demonstrate applicability of this semi-analytical model to multi-well and multi-level pneumatic slug tests. The pneumatic perturbation was applied at discrete intervals in a source well and monitored at discrete vertical intervals in observation wells. The source and observation well pairs were separated by distances of up to 4 m. The analysis yielded vertical profiles of hydraulic conductivity, specific storage, and specific yield at observation well locations. The hydraulic parameter estimates are compared to results from prior pumping and single-well slug tests conducted at the site, as well as to estimates from particle size analyses of sediment collected from boreholes during well installation. The results are in general agreement with results from prior tests and are indicative of a sand and gravel aquifer. Sensitivity analysis show that model identification of specific yield is strongest at late-time. However, the usefulness of late-time data is limited due to the low signal-to-noise ratios.

  15. Fate of triclocarban during soil aquifer treatment: Soil column studies

    KAUST Repository

    Essandoh, H. M K

    2010-04-01

    There are current concerns about the presence of persistent chemicals in recharge water used in soil aquifer treatment systems. Triclocarban (TCC) has been reported as a persistent, high production volume chemical with the potential to bioaccumulate in the environment. It is also known to have adverse effects such as toxicity and suspected endocrine disruption. This study was carried out to study the fate of TCC in soil aquifer treatment (SAT) through laboratory simulations in a soil column. The system performance was evaluated with regards to TCC influent concentration, sand (column) depth, and residence time. Results obtained confirmed the ability of SAT to reduce TCC concentrations in wastewater. Sorption and biodegradation were responsible for TCC removal, the latter mechanism however being unsustainable. The removal efficiency was found to be dependent on concentration and decreased over time and increased with column depth. Within the duration of the experimental run, TCC negatively impacted on treatment performance through a reduction in COD removals observed in the column. © IWA Publishing 2010.

  16. Exploring deep potential aquifer in water scarce crystalline rocks

    Indian Academy of Sciences (India)

    Subash Chandra; E Nagaiah; D V Reddy; V Ananda Rao; Shakeel Ahmed

    2012-12-01

    Characterization of the shear zone with pole–pole electrical resistivity tomography (ERT) was carried out to explore deep groundwater potential zone in a water scarce granitic area. As existing field conditions does not always allow to plant the remote electrodes at sufficiently far of distance, the effect of insufficient distance of remote electrodes on apparent resistivity measurement was studied and shown that the transverse pole–pole array affects less compared to the collinear pole–pole array. Correction factor have been computed for transverse pole–pole array for various positions of the remote electrodes. The above results helped in exploring deep aquifer site, where a 270 m deep well was drilled. Temporal hydro-chemical samples collected during the pumping indicated the hydraulic connectivity between the demarcated groundwater potential fractures. Incorporating all the information derived from different investigations, a subsurface model was synthetically simulated and generated 2D electrical resistivity response for different arrays and compared with the field responses to further validate the geoelectrical response of deep aquifer set-up associated with lineament.

  17. The utility of gravity and water-level monitoring at alluvial aquifer wells in southern Arizona

    Science.gov (United States)

    Pool, D.R.

    2008-01-01

    Coincident monitoring of gravity and water levels at 39 wells in southern Arizona indicate that water-level change might not be a reliable indicator of aquifer-storage change for alluvial aquifer systems. One reason is that water levels in wells that are screened across single or multiple aquifers might not represent the hydraulic head and storage change in a local unconfined aquifer. Gravity estimates of aquifer-storage change can be approximated as a one-dimensional feature except near some withdrawal wells and recharge sources. The aquifer storage coefficient is estimated by the linear regression slope of storage change (estimated using gravity methods) and water-level change. Nonaquifer storage change that does not percolate to the aquifer can be significant, greater than 3 ??Gal, when water is held in the root zone during brief periods following extreme rates of precipitation. Monitor-ing of storage change using gravity methods at wells also can improve understanding of local hydrogeologic conditions. In the study area, confined aquifer conditions are likely at three wells where large water-level variations were accompanied by little gravity change. Unconfined conditions were indicated at 15 wells where significant water-level and gravity change were positively linearly correlated. Good positive linear correlations resulted in extremely large specific-yield values, greater than 0.35, at seven wells where it is likely that significant ephemeral streamflow infiltration resulted in unsaturated storage change. Poor or negative linear correlations indicate the occurrence of confined, multiple, or perched aquifers. Monitoring of a multiple compressible aquifer system at one well resulted in negative correlation of rising water levels and subsidence-corrected gravity change, which suggests that water-level trends at the well are not a good indicatior of overall storage change. ?? 2008 Society of Exploration Geophysicists. All rights reserved.

  18. Major-ion and selected trace-metal chemistry of the Biscayne Aquifer, Southeast Florida

    Science.gov (United States)

    Radell, M.J.; Katz, B.G.

    1991-01-01

    The major-ion and selected trace-metal chemistry of the Biscayne aquifer was characterized as part of the Florida Ground-Water Quality Monitoring Network Program, a multiagency cooperative effort concerned with delineating baseline water quality for major aquifer systems in the State. The Biscayne aquifer is unconfined and serves as the sole source of drinking water for more than 3 million people in southeast Florida. The Biscayne aquifer consists of highly permeable interbedded limestone and sandstone of Pleistocene and Pliocene age underlying most of Dade and Broward Counties and parts of Palm Beach and Monroe Counties. The high permeability is largely caused by extensive carbonate dissolution. Water sampled from 189 wells tapping the Biscayne aquifer was predominantly a calcium bicarbonate type with some mixed types occurring in coastal areas and near major canals. Major - ion is areally uniform throughout the aquifer. According to nonparametric statistical tests of major ions and dissolved solids, the concentrations of calcium, sodium, bicarbonate, and dissolved solids increased significantly with well depth ( 0.05 significance level ), probably a result of less circulation at depth. Potassium and nitrate concentrations decreased significantly with depth. Although the source of recharge to the aquifer varies seasonally, there was no statistical difference in the concentration of major ions in pared water samples from 27 shallow wells collected during wet and dry seasons. Median concentrations for barium, chromium, copper, lead, and manganese were below maximum or secondary maximum contaminant levels set by the US Environmental Protection Agency. The median iron concentration only slightly exceeded the secondary maximum contaminant level. The concentration of barium was significantly related (0.05 significance level) to calcium and bicarbonate concentration. No distinct areal pattern or vertical distribution of the selected trace metals was evident in water from

  19. Influence of aquifer and streambed heterogeneity on the distribution of groundwater discharge

    Directory of Open Access Journals (Sweden)

    E. Kalbus

    2008-08-01

    Full Text Available The spatial distribution of groundwater fluxes through a streambed can be highly variable, most often resulting from a heterogeneous distribution of aquifer and streambed permeabilities along the flow pathways. In a previous study, observed temperature profiles in the streambed of a small stream in Germany were used to calibrate the subsurface parameters of a groundwater flow and heat transport model of the stream-aquifer system. Based on the model results, we defined four scenarios to simulate and assess the interplay of aquifer and streambed heterogeneity on the distribution of groundwater fluxes through the streambed: (a a homogeneous low-K streambed within a heterogeneous aquifer; (b a heterogeneous streambed within a homogeneous aquifer; (c a well connected heterogeneous low-K streambed within a heterogeneous aquifer; and (d a poorly connected heterogeneous low-K streambed within a heterogeneous aquifer. The results showed that the aquifer has a stronger influence on the distribution of groundwater fluxes through the streambed than the streambed itself. However, a homogeneous low-K streambed, a case often implemented in regional-scale groundwater flow models, resulted in a strong homogenization of fluxes, which may have important implications for the estimation of peak mass flows. The simulation results with heterogeneous low-K streambeds, whether or not well connected to the aquifer, were similar to the results of the base case scenario without a separate parameterization of the streambed, despite the lower permeability. We conclude that predictions of water flow and solute transport may significantly benefit from heterogeneous distributions of both aquifer and streambed properties in numerical simulation models.

  20. Hydrogeochemical study of water in some aquifers of the Estado de Mexico

    International Nuclear Information System (INIS)

    The National Institute of Nuclear Research of Mexico (ININ), has developed a technique that allows to study the association of recharge mechanisms, residence times of the water in the aquifers, as well as the local lithology and the geochemical parameters. The viability of this technique was proven on November 2004 in the aquifers (La Perita, El Tunel y El Pedregal) located in the Asuncion Tepexoyuca, Estado de Mexico. It was observed that so much the aquifer El Tunel like La Perita are used for the human consumption, the aquifer of El Pedregal is used for the fish cultivation. The studies were carried out during March 2003 to November 2004. In the aquifer La Perita the maximum values of the radon concentration (0.76 Bq L-1) they were observed in the summertime time (December). In the spring El Tunel the maximum values of the radon concentration (4.08 Bq L-1) they were observed in the rainy season (September) this increment can be due to the contributions of the recharge of aquifers that it allows the haulage of the radon of other alternating roads of infiltration of the rain water. Of the physicochemical and radiochemical analyses carried out in the water samples of the studied aquifers, it is deduced that they are waters of good quality since for the human consumption since that they are inside on the maximum permissible limits as for their potability according to national and international standards. Likewise it was observed that the water of the aquifers is a single aquifer, since that its differences they due to the time of permanency of the water inside the aquifer. The classification of the underground water deduced that it is calcic and/or magnesic bi carbonated water belonging to the type of meteoric waters of recent infiltration. (Author)

  1. Changing the scale of hydrogeophysical aquifer heterogeneity characterization

    Science.gov (United States)

    Paradis, Daniel; Tremblay, Laurie; Ruggeri, Paolo; Brunet, Patrick; Fabien-Ouellet, Gabriel; Gloaguen, Erwan; Holliger, Klaus; Irving, James; Molson, John; Lefebvre, Rene

    2015-04-01

    Contaminant remediation and management require the quantitative predictive capabilities of groundwater flow and mass transport numerical models. Such models have to encompass source zones and receptors, and thus typically cover several square kilometers. To predict the path and fate of contaminant plumes, these models have to represent the heterogeneous distribution of hydraulic conductivity (K). However, hydrogeophysics has generally been used to image relatively restricted areas of the subsurface (small fractions of km2), so there is a need for approaches defining heterogeneity at larger scales and providing data to constrain conceptual and numerical models of aquifer systems. This communication describes a workflow defining aquifer heterogeneity that was applied over a 12 km2 sub-watershed surrounding a decommissioned landfill emitting landfill leachate. The aquifer is a shallow, 10 to 20 m thick, highly heterogeneous and anisotropic assemblage of littoral sand and silt. Field work involved the acquisition of a broad range of data: geological, hydraulic, geophysical, and geochemical. The emphasis was put on high resolution and continuous hydrogeophysical data, the use of direct-push fully-screened wells and the acquisition of targeted high-resolution hydraulic data covering the range of observed aquifer materials. The main methods were: 1) surface geophysics (ground-penetrating radar and electrical resistivity); 2) direct-push operations with a geotechnical drilling rig (cone penetration tests with soil moisture resistivity CPT/SMR; full-screen well installation); and 3) borehole operations, including high-resolution hydraulic tests and geochemical sampling. New methods were developed to acquire high vertical resolution hydraulic data in direct-push wells, including both vertical and horizontal K (Kv and Kh). Various data integration approaches were used to represent aquifer properties in 1D, 2D and 3D. Using relevant vector machines (RVM), the mechanical and

  2. Innovative reactive layer to enhance soil aquifer treatment: successful installation in the Llobregat aquifer (Catalonia, ne Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, M.; Gilbert, O.; Bernat, X.; Valhondo, C.; Kock-Schulmeyer, M.; Huerta-Fontela, M.; Colomer, M. V.

    2014-10-01

    The Life+ ENSAT project has demonstrated the effectiveness of a reactive organic layer on the improvement of recharge water quality in an aquifer recharge system. The vegetal compost layer was installed at the bottom of an existing infiltration pond in the Llobregat Lower Valley (Barcelona region) with the purpose of promoting biodegradation and improving the removal emerging micro-pollutants from Llobregat River water. A comprehensive monitoring of water quality including bulk chemistry, emerging micro-pollutants and priority substances indicated that hydro biochemical changes within the organic layer enhance denitrification processes and reduce the levels of gemfibrozil and carbamazepine TP. This effect is due to the release of dissolved organic carbon which promotes biodegradation processes at local scale in the unsaturated zones, without affecting the furthest piezometers. The reactive layer is still active more than 3 years after its installation. The economic assessment of this innovative reactive layer shows that it is a promising solution for the improvement of aquifer recharge with low quality waters, not only technically but also from the economic sustainability standpoint. (Author)

  3. Innovative reactive layer to enhance soil aquifer treatment: successful installation in the Llobregat aquifer (Catalonia, ne Spain)

    International Nuclear Information System (INIS)

    The Life+ ENSAT project has demonstrated the effectiveness of a reactive organic layer on the improvement of recharge water quality in an aquifer recharge system. The vegetal compost layer was installed at the bottom of an existing infiltration pond in the Llobregat Lower Valley (Barcelona region) with the purpose of promoting biodegradation and improving the removal emerging micro-pollutants from Llobregat River water. A comprehensive monitoring of water quality including bulk chemistry, emerging micro-pollutants and priority substances indicated that hydro biochemical changes within the organic layer enhance denitrification processes and reduce the levels of gemfibrozil and carbamazepine TP. This effect is due to the release of dissolved organic carbon which promotes biodegradation processes at local scale in the unsaturated zones, without affecting the furthest piezometers. The reactive layer is still active more than 3 years after its installation. The economic assessment of this innovative reactive layer shows that it is a promising solution for the improvement of aquifer recharge with low quality waters, not only technically but also from the economic sustainability standpoint. (Author)

  4. Potentiometric surface, 2012, and water-level differences, 2005-12, of the Sparta Aquifer in north-central Louisiana

    Science.gov (United States)

    McGee, Benton D.; Brantly, Jeffrey A.

    2015-01-01

    The Sparta aquifer is used in 15 parishes in north-central Louisiana, primarily for public supply and industrial purposes. Of those parishes, eight (Bienville, Claiborne, Jackson, Lincoln, Ouachita, Union, Webster, and Winn) rely on the Sparta aquifer as their principal source of groundwater. In 2010, withdrawals from the Sparta aquifer in Louisiana totaled 63.11 million gallons per day (Mgal/d), a reduction of more than 11 percent from 1995, when the highest rate of withdrawals (71.32 Mgal/d) from the Sparta aquifer were documented. The Sparta aquifer provides water for a variety of purposes which include public supply (34.61 Mgal/d), industrial (25.60 Mgal/d), rural domestic (1.50 Mgal/d), and various agricultural (1.40 Mgal/d). Of the 13 major aquifers or aquifer systems in Louisiana, the Sparta aquifer is currently (2012) the sixth most heavily pumped. The Sparta aquifer is the second most heavily pumped aquifer in Arkansas, which borders Louisiana to the north. In 2005, 170 Mgal/d were withdrawn from the Sparta aquifer in eastern and southern Arkansas; of that total, about 15.55 Mgal/d were withdrawn from the aquifer in Union County, which borders Claiborne and Union Parishes to the north. By 1997, a large cone of depression (a cone-shaped depression in the potentiometric surface caused by and centered on a pumping well or wells) in the Sparta aquifer centered over Union County had merged with the cone of depression at West Monroe. In 2004, the rate of withdrawal from the Sparta aquifer in Union County began to decline and water levels in the aquifer began to rise in nearby areas of Arkansas and Louisiana.

  5. Geohydrology of the shallow aquifers in the Denver metropolitan area, Colorado

    Science.gov (United States)

    Robson, Stanley G.

    1996-01-01

    The Denver metropolitan area is underlain by shallow layers of water-bearing sediments (aquifers) consisting of unconsolidated gravel, sand, silt, and clay. The depth to water in these aquifers is less than 20 feet in much of the area, and the aquifers provide a ready source of water to numerous shallow, small-capacity wells. The shallow depth to water also makes the aquifers susceptible to contamination from the land surface. Water percolating downward from residential, commercial, and industrial property, spills of hazardous materials, and leaks from underground storage tanks and pipelines can cause contaminants to enter the shallow aquifers. Wet basements, unstable foundation materials, and waterlogged soils also are common in areas of very shallow ground water.Knowledge of the extent, thickness, and water-table altitude of the shallow aquifers is incomplete. This, coupled with the complexity of development in this large metropolitan area, makes effective use, management, and protection of these aquifers extremely difficult. Mapping of the geologic and hydrologic characteristics of these aquifers would provide the general public and technical users with information needed to better use, manage, and protect this water resource. A study to map the geohydrology of shallow aquifers in the Denver metropolitan area was begun in 1994. The work was undertaken by the U.S. Geological Survey in cooperation with the U.S. Army-Rocky Mountain Arsenal, U.S. Department of Energy-Rocky Flats Field Office, Colorado Department of Public Health and Environment, Colorado Department of Natural Resources-State Engineers Office, Denver Water Department, Littleton-Englewood Wastewater Treatment Plant, East Cherry Creek Valley Water and Sanitation District, Metro Wastewater Reclamation District, Willows Water District, and the cities of Aurora, Lakewood, and Thornton.This report presents the results of a systematic mapping of the extent, thickness, and water-table altitude of the shallow

  6. Chemograph analysis of two herbicides in a German karst aquifer

    Science.gov (United States)

    Hillebrand, Olav; Nödler, Karsten; Licha, Tobias; Sauter, Martin; Geyer, Tobias

    2013-04-01

    The dynamic of spring discharge of mature karst aquifers shows after strong precipitation events: Karst spring discharge increases rapidly and strongly, the chemical composition of the spring water is altered and contaminants may be transported from the land-surface towards the spring with the percolating rainwater. Contrary to rapid water transport, high travel times have been observed for parts of the spring discharge, employing stable isotopes as indicators. Monitoring the concentrations of Ca2+ and Cl- in spring water after a precipitation event one may observe the following: After a first increase, the concentrations of Ca2+ drop below the pre-event value, due to dilution with lowly mineralized rain water. On the other hand the concentrations of Cl- increase quickly and return to their background values nearly as fast. This difference in behavior arises from the different origins of these two inorganic ions. Ca2+ in spring water originates mainly from the dissolution of the carbonatic bedrock, while Cl- might be transported from the land-surface (e.g. from road salt) towards the spring. To investigate the dynamic of water in the Gallusquelle catchment in southwest Germany a one year sampling campaign was conducted, using different herbicides as indicator compounds. Depending on discharge conditions the sampling interval varied between 3 hours and several days. Among others, the currently applied and chemically unstable metazachlor was observed together with atrazine, which is prohibited since more than 20 years in Germany. While the detection frequency of atrazine in the spring water samples was nearly 100%, the concentrations ranged only up to 5.2 ng/L. On the other hand, the currently applied metazachlor was only detected in 30.7% of the samples, but its maximum concentration was 71.9 ng/L. An interesting feature was the different temporal concentration pattern of the two investigated herbicides: After precipitation events the concentration of metazachlor in

  7. Estimation of uranium migration parameters in sandstone aquifers.

    Science.gov (United States)

    Malov, A I

    2016-03-01

    The chemical composition and isotopes of carbon and uranium were investigated in groundwater samples that were collected from 16 wells and 2 sources in the Northern Dvina Basin, Northwest Russia. Across the dataset, the temperatures in the groundwater ranged from 3.6 to 6.9 °C, the pH ranged from 7.6 to 9.0, the Eh ranged from -137 to +128 mV, the total dissolved solids (TDS) ranged from 209 to 22,000 mg L(-1), and the dissolved oxygen (DO) ranged from 0 to 9.9 ppm. The (14)C activity ranged from 0 to 69.96 ± 0.69 percent modern carbon (pmC). The uranium content in the groundwater ranged from 0.006 to 16 ppb, and the (234)U:(238)U activity ratio ranged from 1.35 ± 0.21 to 8.61 ± 1.35. The uranium concentration and (234)U:(238)U activity ratio increased from the recharge area to the redox barrier; behind the barrier, the uranium content is minimal. The results were systematized by creating a conceptual model of the Northern Dvina Basin's hydrogeological system. The use of uranium isotope dating in conjunction with radiocarbon dating allowed the determination of important water-rock interaction parameters, such as the dissolution rate:recoil loss factor ratio Rd:p (a(-1)) and the uranium retardation factor:recoil loss factor ratio R:p in the aquifer. The (14)C age of the water was estimated to be between modern and >35,000 years. The (234)U-(238)U age of the water was estimated to be between 260 and 582,000 years. The Rd:p ratio decreases with increasing groundwater residence time in the aquifer from n × 10(-5) to n × 10(-7) a(-1). This finding is observed because the TDS increases in that direction from 0.2 to 9 g L(-1), and accordingly, the mineral saturation indices increase. Relatively high values of R:p (200-1000) characterize aquifers in sandy-clayey sediments from the Late Pleistocene and the deepest parts of the Vendian strata. In samples from the sandstones of the upper part of the Vendian strata, the R:p value is ∼ 24, i.e., sorption processes are

  8. Targeted Proteomics Approaches To Monitor Microbial Activity In Basalt Aquifer

    Science.gov (United States)

    Paszczynski, A. J.; Paidisetti, R.

    2007-12-01

    Microorganisms play a major role in biogeochemical cycles of the Earth. Information regarding microbial community composition can be very useful for environmental monitoring since the short generation times of microorganisms allows them to respond rapidly to changing environmental conditions. Microbial mediated attenuation of toxic chemicals offers great potential for the restoration of contaminated environments in an ecologically acceptable manner. Current knowledge regarding the structure and functional activities of microbial communities is limited, but more information is being acquired every day through many genomic- and proteomic- based methods. As of today, only a small fraction of the Earth's microorganisms has been cultured, and so most of the information regarding the biodegradation and therapeutic potentials of these uncultured microorganisms remains unknown. Sequence analysis of DNA and/or RNA has been used for identifying specific microorganisms, to study the community composition, and to monitor gene expression providing limited information about metabolic state of given microbial system. Proteomic studies can reveal information regarding the real-time metabolic state of the microbial communities thereby aiding in understanding their interaction with the environment. In research described here the involvement of microbial communities in the degradation of anthropogenic contaminants such as trichloroethylene (TCE) was studied using mass spectrometry-based proteomics. The co- metabolic degradation of TCE in the groundwater of the Snake River Plain Aquifer at the Test Area North (TAN) site of Idaho National Laboratory (INL) was monitored by the characterization of peptide sequences of enzymes such as methane monooxygenases (MMOs). MMOs, expressed by methanotrophic bacteria are involved in the oxidation of methane and non-specific co-metabolic oxidation of TCE. We developed a time- course cell lysis method to release proteins from complex microbial

  9. The University of Minnesota aquifer thermal energy storage (ATES) field test facility -- system description, aquifer characterization, and results of short-term test cycles

    Energy Technology Data Exchange (ETDEWEB)

    Walton, M.; Hoyer, M.C.; Eisenreich, S.J.; Holm, N.L.; Holm, T.R.; Kanivetsky, R.; Jirsa, M.A.; Lee, H.C.; Lauer, J.L.; Miller, R.T.; Norton, J.L.; Runke, H. (Minnesota Geological Survey, St. Paul, MN (United States))

    1991-06-01

    Phase 1 of the Aquifer Thermal Energy Storage (ATES) Project at the University of Minnesota was to test the feasibility, and model, the ATES concept at temperatures above 100{degrees}C using a confined aquifer for the storage and recovery of hot water. Phase 1 included design, construction, and operation of a 5-MW thermal input/output field test facility (FTF) for four short-term ATES cycles (8 days each of heat injection, storage, and heat recover). Phase 1 was conducted from May 1980 to December 1983. This report describes the FTF, the Franconia-Ironton-Galesville (FIG) aquifer used for the test, and the four short-term ATES cycles. Heat recovery; operational experience; and thermal, chemical, hydrologic, and geologic effects are all included. The FTF consists of monitoring wells and the source and storage well doublet completed in the FIG aquifer with heat exchangers and a fixed-bed precipitator between the wells of the doublet. The FIG aquifer is highly layered and a really anisotropic. The upper Franconia and Ironton-Galesville parts of the aquifer, those parts screened, have hydraulic conductivities of {approximately}0.6 and {approximately}1.0 m/d, respectively. Primary ions in the ambient ground water are calcium and magnesium bicarbonate. Ambient temperature FIG ground water is saturated with respect to calcium/magnesium bicarbonate. Heating the ground water caused most of the dissolved calcium to precipitate out as calcium carbonate in the heat exchanger and precipitator. Silica, calcium, and magnesium were significantly higher in recovered water than in injected water, suggesting dissolution of some constituents of the aquifer during the cycles. Further work on the ground water chemistry is required to understand water-rock interactions.

  10. Distribution of sulphur isotopes of sulphates in groundwaters from the principal artesian aquifer of Florida and the Edwards aquifer of Texas, United States of America

    International Nuclear Information System (INIS)

    New information on the sources of sulphate dissolved in groundwater is obtainable from the measurement of the sulphur isotope composition of sulphates. Field studies in the Floridan aquifer, Florida, and the Edwards aquifer, Texas, show that the use of sulphur isotope data in conjunction with hydrologic and geochemical techniques permits refinements of interpretation. In the Floridan the interpretation of the chemical data, particularly the SO42- concentration and the SO42-/Cl- ratio, leads to the conclusion that recharging maritime rainfall, solution of intraformational gypsum, and mixing with ocean-like saline waters are the sources of sulphate in the groundwater. Sulphur isotope data substantiate this interpretation. The Edwards in the area studied can be separated into two hydrologie units on the basis of water chemistry and aquifer characteristics. The sulphide-free waters in the part of the aquifer upgradient from a distinct sulphide boundary are low in sulphate (less than 100 mg/1) and contain no sulphide. The waters downgradient from that boundary contain greater than 150 mg/1 sulphate and all contain measurable quantities of sulphide. Interpretation of the SO42- concentration and SO42-/Cl ratio on the basis of the Florida study leads to the erroneous conclusion that the solution of intraformational gypsum is again a major source of sulphate in the sulphide-free part of the aquifer. Isotope analyses, however, show that the gypsum is likely to be Permian in age and introduced into the aquifer by the recharge water. The absence of evidence for enrichment in 34S in the sulphate in the sulphide-bearing portion of the aquifer leads to the possibility of H2S migration upgradient from downdip oil fields. (author)

  11. Upper Basalt-Confined Aquifer System in the Southern Hanford Site

    International Nuclear Information System (INIS)

    The 1990 DOE Tiger Team Finding GW/CF-202 found that the hydrogeologic regime at the Hanford Site was inadequately characterized. This finding also identified the need for completing a study of the confined aquifer in the central and southern portions of the Hanford Site. The southern portion of the site is of particular interest because hydraulic-head patterns in the upper basalt-confined aquifer system indicate that groundwater from the Hanford central plateau area, where contaminants have been found in the aquifer, flows southeast toward the southern site boundary. This results in a potential for offsite migration of contaminants through the upper basalt-confined aquifer system. Based on the review presented in this report, available hydrogeologic characterization information for the upper basalt-confined aquifer system in this area is considered adequate to close the action item. Recently drilled offsite wells have provided additional information on the structure of the aquifer system in and near the southern part of the Hanford Site. Information on hydraulic properties, hydrochemistry, hydraulic heads and flow directions for the upper basalt-confined aquifer system has been re-examined and compiled in recent reports including Spane and Raymond (1993), Spane and Vermeul ( 1994), and Spane and Webber (1995)

  12. Characterization of flow dynamics and vulnerability in a coastal aquifer system.

    Science.gov (United States)

    Murgulet, Dorina; Tick, Geoffrey R

    2013-01-01

    Traditional aquifer vulnerability techniques primarily rely on spatial property data for a region and are limited by their ability to directly or indirectly assess flow and transport processes occurring from the surface to depth within an aquifer system. The main objective of this study was to investigate groundwater vulnerability in terms of aquifer interconnectivity and flow dynamics. A combination of stable isotopes, groundwater age-dating (radiocarbon), and geomorphic/geogenic spatial analyses was applied to a regional, highly developed coastal aquifer to explain the presence of nitrate at depth. The average δ(13) C value (-17.3 ± 2‰ VPDB, n = 27) is characteristic of groundwater originating from locally infiltrated precipitation through extensively cultivated soils. The average δ(18) O and δD values (-4.0 ± 0.1‰ VSMOW, n = 27; δD: -19.3 ± 1‰ VSMOW, n = 27, respectively) are similar to precipitation water derived from maritime sources feeding the region's surface water and groundwater. Stable and radioactive isotopes reveal significant mixing between shallow and deep aquifers due to high velocities, hydraulic connection, and input of local recharge water to depths. Groundwater overdevelopment enhances deeper and faster modern water downward flux, amplifying aquifer vulnerability. Therefore, aquifer vulnerability is a variable, dependent on the type and degree of stress conditions experienced by a groundwater system as well as the geospatial properties at the near surface.

  13. Hydrogeology and water-supply potential of the water-table aquifer on Dauphin Island, Alabama

    Science.gov (United States)

    Kidd, R.E.

    1988-01-01

    The water table aquifer on Dauphin Island, Alabama, consists of a thin veneer of Holocene sand and an underlying Pleistocene unit locally known as the Gulfport Formation. The aquifer is from 28 to 35 ft thick with a thick marine clay at its base. Water in the aquifer generally is low in chloride content except near the coast. Excessively high iron concentrations in groundwater were found locally. A two-dimensional finite-difference groundwater flow model of the water table aquifer on Dauphin Island was used in the steady-state mode to evaluate the flow system under steady-state conditions. Model input data were obtained primarily from 40 test wells, 2 aquifer tests, continuous recording of groundwater levels, and rainfall. The model was calibrated to the low water-table conditions of July 1985 and high water table conditions of April 1985. The model was also used to simulate pumpage from the aquifer under transient conditions with no rainfall. Patterns of computed head changes compared favorably to the natural recession of water levels for the periods of April to May 1985 and May to June 1985. Simulation of groundwater withdrawals in the transient model showed the feasibility of producing 0.6 million gallons/day from eight wells that tap the water table aquifer without inducing lateral seawater encroachment. (USGS)

  14. Hydrochemical synthesis of Northern Switzerland: aquifers in Dogger, Lias, Keuper and Muschelkalk strata

    International Nuclear Information System (INIS)

    This report presents hydrochemical information for groundwaters from the Muschelkalk, Keuper, Lias, and Dogger aquifers, and constitutes the third and last part of a comprehensive hydrochemical synthesis of groundwaters from aquifers in northern Switzerland and adjacent areas. The data are mainly the results of the Nagra regional and supervisory programme, completed by a number of published analyses from external sources. From these data it was possible to show differences of waters specific to the formations concerned, particularly with the help of the relationships of minor elements and isotopes. Deep groundwaters in the Muschelkalk and Keuper aquifers distinguish themselves by solution of gypsum/anhydrite and halite, sometimes also by cation exchange or solution of mirabilite. In the deep groundwaters of the Lias and Dogger aquifers processes mainly of cation exchange and mixing with marine pore waters define the chemical compositions. Using specific hydrochemical attributes, in some cases it is possible to recognize mixing processes between groundwaters of different aquifers. Thus, it could be shown that the waters in that portion of the Muschelkalk aquifer thrusted over the southrim of the Folded Jura contain an important proportion of sodium chloride groundwaters which have ascended via faults from deeper aquifers. In the Muschelkalk of the Tabular Jura there are indications of such hydraulic connections in the area of the northern margin of the Permo-Carboniferous Trough of Northern Switzerland, as well as in the west, where the Tabular Jura is influenced by Rhine Graben tectonics. (author) figs., tabs., refs

  15. Spatial variation in microbial community structure, richness, and diversity in an alluvial aquifer.

    Science.gov (United States)

    Medihala, P G; Lawrence, J R; Swerhone, G D W; Korber, D R

    2012-09-01

    Relatively little is known regarding the spatial variability of microbial communities in aquifers where well fouling is an issue. In this study 2 water wells were installed in an alluvial aquifer located adjacent to the North Saskatchewan River and an associated piezometer network developed to facilitate the study of microbial community structure, richness, and diversity. Carbon utilization data analysis revealed reduced microbial activity in waters collected close to the wells. Functional PCR and quantitative PCR analysis indicated spatial variability in the potential for iron-, sulphate-, and nitrate-reducing activity at all locations in the aquifer. Denaturing gradient gel electrophoresis analysis of aquifer water samples using principal components analyses indicated that the microbial community composition was spatially variable, and denaturing gradient gel electrophoresis sequence analysis revealed that bacteria belonging to the genera Acidovorax , Rhodobacter , and Sulfuricurvum were common throughout the aquifer. Shannon's richness (H') and Pielou's evenness (J') indices revealed a varied microbial diversity (H' = 1.488-2.274) and an even distribution of microbial communities within the aquifer (J' = 0.811-0.917). Overall, these analyses revealed that the aquifer's microbial community varied spatially in terms of composition, richness, and metabolic activity. Such information may facilitate the diagnosis, prevention, and management of fouling. PMID:22913282

  16. Effect of faults on fluid flow and chloride contamination in a carbonate aquifer system

    Science.gov (United States)

    Maslia, M.L.; Prowell, D.C.

    1990-01-01

    A unified, multidiscipline hypothesis is proposed to explain the anomalous pattern by which chloride has been found in water of the Upper Floridan aquifer in Brunswick, Glynn County, Georgia. Analyses of geophysical, hydraulic, water chemistry, and aquifer test data using the equivalent porous medium (EPM) approach are used to support the hypothesis and to improve further the understanding of the fracture-flow system in this area. Using the data presented herein we show that: (1) four major northeast-southwest trending faults, capable of affecting the flow system of the Upper Floridan aquifer, can be inferred from structural analysis of geophysical data and from regional fault patterns; (2) the proposed faults account for the anomalous northeastward elongation of the potentiometric surface of the Upper Floridan aquifer; (3) the faults breach the nearly impermeable units that confine the Upper Floridan aquifer from below, allowing substantial quantities of water to leak vertically upward; as a result, aquifer transmissivity need not be excessively large (as previously reported) to sustain the heavy, long-term pumpage at Brunswick without developing a steep cone of depression in the potentiometric surface; (4) increased fracturing at the intersection of the faults enhances the development of conduits that allow the upward migration of high-chloride water in response to pumping from the Upper Floridan aquifer; and (5) the anomalous movement of the chloride plume is almost entirely controlled by the faults. ?? 1990.

  17. Saturated and Unsaturated Flow due to Tidal Fluctuation and Rainfall in a Coastal Aquifer

    Science.gov (United States)

    Yeh, Hund-Der; Chuang, Mo-Hsiung; Chang, Chia-Hao

    2016-04-01

    The prediction of groundwater level fluctuations due to tidal waves propagation and localized recharge in coastal aquifers is important for the development and management of water resources in coastal areas. Most of the past models for the recharge problem consider either saturated flow or unsaturated flow in the aquifers. However, it is expected that the recharge sources infiltrating from the ground surface have significant impact on the hydraulic heads in saturated and unsaturated zones of an unconfined aquifer in reality. The objective of this study is to derive a closed-form analytical expression for predicting tidal responses in a coastal aquifer system with considering rainfall recharge as well as coupled saturated and unsaturated flow. The model is composed of a linearized Richards equation for unsaturated flow coupled with the saturated groundwater flow equation. The top boundary at the ground surface is represented by the flux condition with a source term denoting the recharge in the coastal aquifer system. The solution of the model is developed in Cartesian coordinates based on the methods of Laplace transform and double-integral transform. On the basis of the analytical solution, the groundwater head fluctuations induced by the joint effect of rainfall and oceanic tides is examined in saturated and unsaturated zones of the aquifer. In addition, the influences of the unsaturated flow on the water table movement are also investigated and discussed. Key words: analytical solution, unsaturated flow, coastal aquifer.

  18. Hydrochemical investigations for delineating salt-water intrusion into the coastal aquifer of Maharlou Lake, Iran

    Science.gov (United States)

    Jahanshahi, Reza; Zare, Mohammad

    2016-09-01

    Groundwater quality depends on different factors such as geology, lithology, properties of aquifer, land use, the physical condition of boundaries etc. Studying these factors can help users to manage groundwater quality. This study deals with the groundwater quality of an aquifer located in the southeastern part of Maharlou salt lake, Iran. This lake is located in the southeast of Shiraz and is the outlet of Shiraz sewages. Due to overexploitation of groundwater from the aquifer, the gradient of water table is from the lake towards the aquifer and therefore, saline water migrates to the aquifer. The phenomenon of salt water intrusion contributes to the deterioration of groundwater. In this research, groundwater types, maps of iso EC and iso ions, ion exchange in the mixing of fresh and salt water, salinity variation of the groundwater in the profile of well water column, and the salinity-time variation of the groundwater were studied. The gradual increase of the salinity of groundwater with depth from top to down in the aquifer indicates that salt water is located under fresh water. The time variation of physical and chemical parameters in the groundwater discharged from a well shows that the saline water in the bottom of the aquifer moves upward and destroys the quality of groundwater in the study area. Furthermore, Sachoun geological formation formed by evaporate deposits and evaporation from shallow groundwater are two other factors which decrease the groundwater quality.

  19. A simple tool for the computation of the stream-aquifer coefficient.

    Science.gov (United States)

    Cousquer, Yohann; Pryet, Alexandre; Dupuy, Alain

    2015-04-01

    Most groundwater models consider a river network in interaction with aquifers, where the stream-aquifer boundary is usually modeled with a Cauchy-type boundary condition. This condition is parameterized with the so-called "river coefficient", which is a lumped parameter representing the effects of numerous geometric and hydrodynamic controlling factors. The value of the river coefficient is essential for the quantification of stream-aquifer flow but is challenging to determine. In recent years, many formulations for the river coefficient have been proposed from analytical and numerical approaches. However, these methods are either too simple to be realistic or too complex to be easily implemented by groundwater modelers. We propose a simple tool to infer the value of the river coefficient from a fine-grid numerical model. This tool allows the simple and fast computation of the river coefficient with various stream geometries and hydraulic parameters. A Python-based pre- and post-processor has been developed, which reduces the contribution of the operator to the definition of the model parameters: river geometry and aquifer properties. The numerical model is implemented with the USGS SUTRA finite element model and considers an aquifer in interaction with a stream in a 2D vertical cross-section. A Dirichlet-type boundary condition is imposed at the stream-aquifer interface. The linearity between the stream-aquifer flow and the head difference between river and the aquifer has been verified. For a given parameter set, the value of river coefficient is estimated by linear regression for different values of head difference between the river and the aquifer. The innovation is that the mesh size of the regional model is also considered for the computation of the river coefficient. This tool has been used to highlight the importance of parameters that were usually neglected for the computation of the river coefficient. The results of this work will be made available to the

  20. Hydrochemistry and hydrogeologic conditions within the Hanford Site upper basalt confined aquifer system

    International Nuclear Information System (INIS)

    As part of the Hanford Site Ground-Water Surveillance Project, Flow System Characterization Task. Pacific Northwest Laboratory examines the potential for offsite migration of contamination within the upper basalt confined aquifer system for the US Department of Energy (DOE). As part of this activity, groundwater samples were collected over the past 2 years from selected wells completed in the upper Saddle Mountains Basalt. The hydrochemical and isotopic information obtained from these groundwater samples provides hydrologic information concerning the aquifer-flow system. Ideally, when combined with other hydrologic property information, hydrochemical and isotopic data can be used to evaluate the origin and source of groundwater, areal groundwater-flow patterns, residence and groundwater travel time, rock/groundwater reactions, and aquifer intercommunication for the upper basalt confined aquifer system. This report presents the first comprehensive Hanford Site-wide summary of hydrochemical properties for the upper basalt confined aquifer system. This report provides the hydrogeologic characteristics (Section 2.0) and hydrochemical properties (Section 3.0) for groundwater within this system. A detailed description of the range of the identified hydrochemical parameter subgroups for groundwater in the upper basalt confined aquifer system is also presented in Section 3.0. Evidence that is indicative of aquifer contamination/aquifer intercommunication and an assessment of the potential for offsite migration of contaminants in groundwater within the upper basalt aquifer is provided in Section 4.0. The references cited throughout the report are given in Section 5.0. Tables that summarize groundwater sample analysis results for individual test interval/well sites are included in the Appendix

  1. Quality of groundwater in the Denver Basin aquifer system, Colorado, 2003-5

    Science.gov (United States)

    Musgrove, MaryLynn; Beck, Jennifer A.; Paschke, Suzanne; Bauch, Nancy J.; Mashburn, Shana L.

    2014-01-01

    Groundwater resources from alluvial and bedrock aquifers of the Denver Basin are critical for municipal, domestic, and agricultural uses in Colorado along the eastern front of the Rocky Mountains. Rapid and widespread urban development, primarily along the western boundary of the Denver Basin, has approximately doubled the population since about 1970, and much of the population depends on groundwater for water supply. As part of the National Water-Quality Assessment Program, the U.S. Geological Survey conducted groundwater-quality studies during 2003–5 in the Denver Basin aquifer system to characterize water quality of shallow groundwater at the water table and of the bedrock aquifers, which are important drinking-water resources. For the Denver Basin, water-quality constituents of concern for human health or because they might otherwise limit use of water include total dissolved solids, fluoride, sulfate, nitrate, iron, manganese, selenium, radon, uranium, arsenic, pesticides, and volatile organic compounds. For the water-table studies, two monitoring-well networks were installed and sampled beneath agricultural (31 wells) and urban (29 wells) land uses at or just below the water table in either alluvial material or near-surface bedrock. For the bedrock-aquifer studies, domestic- and municipal-supply wells completed in the bedrock aquifers were sampled. The bedrock aquifers, stratigraphically from youngest (shallowest) to oldest (deepest), are the Dawson, Denver, Arapahoe, and Laramie-Fox Hills aquifers. The extensive dataset collected from wells completed in the bedrock aquifers (79 samples) provides the opportunity to evaluate factors and processes affecting water quality and to establish a baseline that can be used to characterize future changes in groundwater quality. Groundwater samples were analyzed for inorganic, organic, isotopic, and age-dating constituents and tracers. This report discusses spatial and statistical distributions of chemical constituents

  2. Continental hydrosystem modelling: the concept of nested stream–aquifer interfaces

    Directory of Open Access Journals (Sweden)

    N. Flipo

    2014-01-01

    Full Text Available Recent developments in hydrological modelling are based on a view of the interface being a single continuum through which water flows. These coupled hydrological-hydrogeological models, emphasising the importance of the stream–aquifer interface, are more and more used in hydrological sciences for pluri-disciplinary studies aiming at investigating environmental issues. This notion of a single continuum, which is accepted by the hydrological modellers, originates in the historical modelling of hydrosystems based on the hypothesis of a homogeneous media that led to the Darcy law. There is then a need to first bridge the gap between hydrological and eco-hydrological views of the stream–aquifer interfaces, and, secondly, to rationalise the modelling of stream–aquifer interface within a consistent framework that fully takes into account the multi-dimensionality of the stream–aquifer interfaces. We first define the concept of nested stream–aquifer interfaces as a key transitional component of continental hydrosystem. Based on a literature review, we then demonstrate the usefulness of the concept for the multi-dimensional study of the stream–aquifer interface, with a special emphasis on the stream network, which is identified as the key component for scaling hydrological processes occurring at the interface. Finally we focus on the stream–aquifer interface modelling at different scales, with up-to-date methodologies and give some guidances for the multi-dimensional modelling of the interface using the innovative methodology MIM (Measurements-Interpolation-Modelling, which is graphically developed, scaling in space the three pools of methods needed to fully understand stream–aquifer interfaces at various scales. The outcome of MIM is the localisation in space of the stream–aquifer interface types that can be studied by a given approach. The efficiency of the method is demonstrated with two approaches from the local (~1 m to the

  3. A New Approach for Assessing Aquifer Sustainability and the Impact of Proposed Management Actions

    Science.gov (United States)

    Butler, J. J., Jr.; Whittemore, D. O.; Wilson, B. B.

    2015-12-01

    Aquifers are under stress worldwide as a result of large imbalances between inflows and outflows. These imbalances are particularly severe in aquifers in semi-arid regions that are heavily pumped for irrigation, such as the High Plains aquifer (HPA) in the United States. The water resources community has responded by placing an increasing emphasis on more sustainable management plans. To aid in the formulation of such plans, we have developed a simple, water-balance-based approach for rapid assessment of the impact of proposed management actions and the prospects for aquifer sustainability. This theoretically sound approach is particularly well suited for assessing the short- to medium-term (years to a few decades) response to management actions in seasonably pumped aquifers. The net inflow (capture) term of the aquifer water balance can also be directly calculated from water-level and water-use data with this approach. Application to the data-rich portion of the HPA in the state of Kansas reveals that practically achievable reductions in annual pumping would have a large impact. For example, a 22% reduction in average annual water use would have stabilized areally averaged water levels across northwest Kansas from 1996 to 2013 because of larger-than-expected and near-constant net inflows. Whether this is a short-term phenomenon or a path to long-term sustainability, however, has yet to be determined. Water resources managers are often in a quandary about the most effective use of scarce funds for data collection in support of aquifer assessment and management activities. This work demonstrates that a strong emphasis should be placed on collection of reliable water-use data; greater resources devoted to direct measurement of pumping will yield deeper insights into an aquifer's future. The Kansas HPA is similar to many other regional aquifers supporting critically needed agricultural production, so this approach should prove of value far beyond the borders of Kansas.

  4. Contribution of isotopic indicators to the assessment of groundwater mixture between Continental Intercalaire and Djeffara Aquifers (South-Eastern Tunisia)

    International Nuclear Information System (INIS)

    The Continental Intercalate and the Djeffara aquifers are the most important groundwater resources in Southern Tunisia. Previous hydrogeologic and isotopic studies (180, 2H, 3H, 14C) allow to define the main hydrodynamic and hydrochemical characteristics for each aquifer. The Continental Intercalaire aquifer, which has important water reserves contains very old groundwater with low 14C activities and very depleted values of stable isotopes (18O, 2H). This is why this aquifer is considered as fossil and contains non renewable resources. Compared to the Continental Intercalate aquifer, Djeffara aquifer has more scattered stable isotopes values which confirms that there are different, water origins. Near to the El Hamma faults, isotopic contents of Djeffara aquifer are very similar to the isotopic signature of the Continental Intercalate, indicating mixing flows between the two systems and showing that the recharge of Djeffara of Gabes is partially ensured by the discharge of the old water of the Continental Intercalate through faults. (author)

  5. Groundwater, surface-water, and water-chemistry data from C-aquifer monitoring program, northeastern Arizona, 2005-11

    Science.gov (United States)

    Brown, Christopher R.; Macy, Jamie P.

    2012-01-01

    The C aquifer is a regionally extensive multiple-aquifer system supplying water for municipal, agricultural, and industrial use in northeastern Arizona, northwestern New Mexico, and southeastern Utah. An increase in groundwater withdrawals from the C aquifer coupled with ongoing drought conditions in the study area increase the potential for drawdown within the aquifer. A decrease in the water table and potentiometric surface of C aquifer is illustrated locally by the drying up of Obed Meadows, a natural peat deposit, and Hugo Meadows, a natural wetland, both south of Joseph City, Arizona. Continual increase in water use from the C aquifer, including a planned increase in pumpage by the City of Flagstaff, is justification for continued monitoring of the C-aquifer system in order to quantify physical and chemical responses to pumping stresses.

  6. Water resources management in karst aquifers - concepts and modeling approaches

    Science.gov (United States)

    Sauter, M.; Schmidt, S.; Abusaada, M.; Reimann, T.; Liedl, R.; Kordilla, J.; Geyer, T.

    2011-12-01

    Water resources management schemes generally imply the availability of a spectrum of various sources of water with a variability of quantity and quality in space and time, and the availability and suitability of storage facilities to cover various demands of water consumers on quantity and quality. Aquifers are generally regarded as suitable reservoirs since large volumes of water can be stored in the subsurface, water is protected from contamination and evaporation and the underground passage assists in the removal of at least some groundwater contaminants. Favorable aquifer properties include high vertical hydraulic conductivities for infiltration, large storage coefficients and not too large hydraulic gradients / conductivities. The latter factors determine the degree of discharge, i.e. loss of groundwater. Considering the above criteria, fractured and karstified aquifers appear to not really fulfill the respective conditions for storage reservoirs. Although infiltration capacity is relatively high, due to low storativity and high hydraulic conductivities, the small quantity of water stored is rapidly discharged. However, for a number of specific conditions, even karst aquifers are suitable for groundwater management schemes. They can be subdivided into active and passive management strategies. Active management options include strategies such as overpumping, i.e. the depletion of the karst water resources below the spring outflow level, the construction of subsurface dams to prevent rapid discharge. Passive management options include the optimal use of the discharging groundwater under natural discharge conditions. System models that include the superposition of the effect of the different compartments soil zone, epikarst, vadose and phreatic zone assist in the optimal usage of the available groundwater resources, while taking into account the different water reservoirs. The elaboration and implementation of groundwater protection schemes employing well

  7. Groundwater exploration and exploitation of the Caracas aquifer, Venezuela

    International Nuclear Information System (INIS)

    The Caracas valley is bordered by crystalline rocks, and the valley fill (Caracas aquifer) comprises the weathering products of these rocks, such as fluvial gravels and sands, in addition to clay and silts from former lakes. All these sediments intercalate in a very irregular manner. Groundwater recharge below Caracas is pronounced because of significant exfiltrations of drinking water out of the distribution net. This creates an important dilution potential for pollutants and stimulates the development of microbiological activity. These, however, cannot favour groundwater withdrawal from the active recharge zone, because protection measures will be difficult to realize. It is therefore recommended that groundwater exploitation be restricted to the passive recharge zone by wells with filter screens more than 100 m below the surface

  8. Geochemical implications of brine leakage into freshwater aquifers.

    Science.gov (United States)

    Wunsch, Assaf; Navarre-Sitchler, Alexis K; McCray, John E

    2013-01-01

    CO(2) injection into deep saline formations as a way to mitigate climate change raises concerns that leakage of saline waters from the injection formations will impact water quality of overlying aquifers, especially underground sources of drinking water (USDWs). This paper aims to characterize the geochemical composition of deep brines, with a focus on constituents that pose a human health risk and are regulated by the U.S. Environmental Protection Agency (USEPA). A statistical analysis of the NATCARB brine database, combined with simple mixing model calculations, show total dissolved solids and concentrations of chloride, boron, arsenic, sulfate, nitrate, iron and manganese may exceed plant tolerance or regulatory levels. Twelve agricultural crops evaluated for decreased productivity in the event of brine leakage would experience some yield reduction due to increased TDS at brine-USDW ratios of United States are almost three times higher than public and domestic withdrawals.

  9. The supposed radioactive contamination of the Puelche aquifer

    International Nuclear Information System (INIS)

    The paper attempts to clarify the supposed radioactive contamination of the Puelche Aquifer in the Ezeiza Atomic Center Area, Ezeiza, province of Buenos Aires (Argentina). Reports are listed that show categorically that no anthropogenic uranium contamination is present. As far as the nitrates contamination is concerned, it is not generated by the Ezeiza Atomic Center, because the Center is downward from the contaminated zone. It is possible that the contamination is produced by houses in the area without suitable sewage. In the present case the best contribution to the environmental right, besides the adaptation and the systematization of the different legal instruments, is to found the analysis of the facts on the scientific and technical knowledge. (author)

  10. Groundwater Remediation in a Floodplain Aquifer at Shiprock, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, Dave [Navarro Research and Engineering; Miller, David [Navarro Research and Engineering; Kautsky, Mark [U. S. Department of Energy, Office of Legacy Management; Dander, David [Navarro Research and Engineering; Nofchissey, Joni [Navajo Nation Division of Natural Resources

    2016-03-06

    A uranium- and vanadium-ore-processing mill operated from 1954 to 1968 within the Navajo Nation near Shiprock, New Mexico. By September 1986, all tailings and structures on the former mill property were encapsulated in a disposal cell built on top of two existing tailings piles on the Shiprock site (the site) [1]. Local groundwater was contaminated by multiple inorganic constituents as a result of the milling operations. The U.S. Department of Energy (DOE) took over management of the site in 1978 as part of the Uranium Mill Tailings Remedial Action (UMTRA) Project. The DOE Office of Legacy Management currently manages ongoing activities at the former mill facility, including groundwater remediation. Remediation activities are designed primarily to reduce the concentrations and total plume mass of the mill-related contaminants sulfate, uranium, and nitrate. In addition to contaminating groundwater in alluvial and bedrock sediments directly below the mill site, ore processing led to contamination of a nearby floodplain bordering the San Juan River. Groundwater in a shallow alluvial aquifer beneath the floodplain is strongly influenced by the morphology of the river channel as well as changing flows in the river, which provides drainage for regional runoff from the San Juan Mountains of Colorado. As part of a recent study of the floodplain hydrology, a revised conceptual model was developed for the alluvial aquifer along with an updated status of contaminant plumes that have been impacted by more than 10 years of groundwater pumping for site remediation purposes. Several findings from the recent study will be discussed here.

  11. Radiolytic Hydrogen Production in the Subseafloor Basaltic Aquifer.

    Science.gov (United States)

    Dzaugis, Mary E; Spivack, Arthur J; Dunlea, Ann G; Murray, Richard W; D'Hondt, Steven

    2016-01-01

    Hydrogen (H2) is produced in geological settings by dissociation of water due to radiation from radioactive decay of naturally occurring uranium ((238)U, (235)U), thorium ((232)Th) and potassium ((40)K). To quantify the potential significance of radiolytic H2 as an electron donor for microbes within the South Pacific subseafloor basaltic aquifer, we use radionuclide concentrations of 43 basalt samples from IODP Expedition 329 to calculate radiolytic H2 production rates in basement fractures. The samples are from three sites with very different basement ages and a wide range of alteration types. U, Th, and K concentrations vary by up to an order of magnitude from sample to sample at each site. Comparison of our samples to each other and to the results of previous studies of unaltered East Pacific Rise basalt suggests that significant variations in radionuclide concentrations are due to differences in initial (unaltered basalt) concentrations (which can vary between eruptive events) and post-emplacement alteration. However, there is no clear relationship between alteration type and calculated radiolytic yields. Local maxima in U, Th, and K produce hotspots of H2 production, causing calculated radiolytic rates to differ by up to a factor of 80 from sample to sample. Fracture width also greatly influences H2 production, where microfractures are hotspots for radiolytic H2 production. For example, H2 production rates normalized to water volume are 190 times higher in 1 μm wide fractures than in fractures that are 10 cm wide. To assess the importance of water radiolysis for microbial communities in subseafloor basaltic aquifers, we compare electron transfer rates from radiolysis to rates from iron oxidation in subseafloor basalt. Radiolysis appears likely to be a more important electron donor source than iron oxidation in old (>10 Ma) basement basalt. Radiolytic H2 production in the volume of water adjacent to a square cm of the most radioactive SPG basalt may support as

  12. Internal corrosion of carbon steel piping in hot aquifers service

    Directory of Open Access Journals (Sweden)

    Simičić Miloš V.

    2011-01-01

    Full Text Available Internal corrosion of carbon steel pipelines is a major problem encountered in water service. In terms of prediction of the remaining lifetime for water pipelines based on the corrosion allowance, the three main approaches are corrosion modelling, corrosion inhibitor availability, and corrosion monitoring. In this study we used two theoretical corrosion models, CASSANDRA and NORSOK M-506 of quite different origin in order to predict uniform corrosivity of hot aquifers in eight different pipelines. Because of the varying calculation criteria for the different models, these can give very different corrosion rate predictions for the same data input. This is especially true under conditions where the formation of protective films may occur, such as at elevated temperatures. The evaluation of models was conducted by comparison using weight-loss coupons and three corrosion inhibitors were obtained from commercial suppliers. The tests were performed during the 60-day period. Even though inhibitors’ efficiencies of 98% had been achieved in laboratory testing, inhibitors’ availabilities of 85% have been used due to logistics problems and other issues. The results, given in mmpy, i.e. millimeter per year, are very consistent with NORSOK M-506 prediction. This is presumably because the model considers the effect of the formation of a passive iron carbonate film at temperatures above 80 °C and significant reduction in corrosion rate. Corrosion inhibitor A showed a better performance than inhibitors B and C in all cases but the target corrosion rates of less than 0.1 mmpy were achieved for all inhibitors. The chemical type of corrosion inhibitor A is based on quaternary amines mixed with methanol, isopropyl alcohol, xylene and ethylbenzene. Based on the obtained results the carbon steel lifetime of 30 years, provided proper inhibitors are present and 3mm corrosion allowance, can be achieved for hot aquifers service with presented water compositions.

  13. Potential contaminant pathways from hydraulically fractured shale to aquifers.

    Science.gov (United States)

    Myers, Tom

    2012-01-01

    Hydraulic fracturing of deep shale beds to develop natural gas has caused concern regarding the potential for various forms of water pollution. Two potential pathways-advective transport through bulk media and preferential flow through fractures-could allow the transport of contaminants from the fractured shale to aquifers. There is substantial geologic evidence that natural vertical flow drives contaminants, mostly brine, to near the surface from deep evaporite sources. Interpretative modeling shows that advective transport could require up to tens of thousands of years to move contaminants to the surface, but also that fracking the shale could reduce that transport time to tens or hundreds of years. Conductive faults or fracture zones, as found throughout the Marcellus shale region, could reduce the travel time further. Injection of up to 15,000,000 L of fluid into the shale generates high pressure at the well, which decreases with distance from the well and with time after injection as the fluid advects through the shale. The advection displaces native fluids, mostly brine, and fractures the bulk media widening existing fractures. Simulated pressure returns to pre-injection levels in about 300 d. The overall system requires from 3 to 6 years to reach a new equilibrium reflecting the significant changes caused by fracking the shale, which could allow advective transport to aquifers in less than 10 years. The rapid expansion of hydraulic fracturing requires that monitoring systems be employed to track the movement of contaminants and that gas wells have a reasonable offset from faults. PMID:22509908

  14. Geological storage, including costs and risks, in saline aquifers

    International Nuclear Information System (INIS)

    Capture and storage of CO2 can in the short to medium term play a part in sequestering already concentrated CO2 streams, such as from natural gas treatment or ammonia or hydrogen production plants. In the longer perspective CO2 storage may provide an important route to achieve the deep reductions in greenhouse gas emissions to atmosphere to possibly limit anthropogenic climate change. This is believed to be good news for an increasing global population and the global economy -as well as the oil and gas industry- into the 21 st century. The first decision to apply underground storage of carbon dioxide captured from natural gas -as a climate change mitigation effort- was taken by Statoil (operator) and partners in the Sleipner North Sea license in 1990. The second such decision was taken by Statoil (operator) and a different set of partners in the Snoehvit licence in the Barents Sea in the autumn of 2001. Sleipner has been injecting CO2 from 1996 while the Snoehvit project will start up in 2006. At Sleipner the CO2 is both extracted and injected offshore in a highly permeable sandstone formation, the Utsira formation 1000 meters below the seabed. Utsira is overlain by 800 meters of much denser rock. The CO2 injection at Sleipner has been keenly studied in a broadly based, multinational R and D effort, the so called SACS (Saline Aquifer CO2 storage programme). In the Snoehvit case the there will be no surface installations offshore and the CO2 rich natural gas will be sent to shore in a 160 kilometre long pipeline to be processed in an LNG (Liquefied Natural Gas) plant. After removal the CO2 is sent back to the field in a separate pipeline and be injected in a separate formation under the natural gas field itself. The paper will also discuss the safety aspects of CO2 storage in saline aquifers as well as costs associated with CO2 storage

  15. Radiolytic hydrogen production in the subseafloor basaltic aquifer

    Directory of Open Access Journals (Sweden)

    Mary E Dzaugis

    2016-02-01

    Full Text Available Hydrogen (H2 is produced in geological settings by dissociation of water due to radiation from radioactive decay of naturally occurring uranium (238U, 235U, thorium (232Th and potassium (40K. To quantify the potential significance of radiolytic H2 as an electron donor for microbes within the South Pacific subseafloor basaltic aquifer, we use radionuclide concentrations of 43 basalt samples from IODP Expedition 329 to calculate radiolytic H2 production rates in basement fractures. The samples are from three sites with very different basement ages and a wide range of alteration types. U, Th and K concentrations vary by up to an order of magnitude from sample to sample at each site. Comparison of our samples to each other and to the results of previous studies of unaltered East Pacific Rise basalt suggests that significant variations in radionuclide concentrations are due to differences in initial (unaltered basalt concentrations (which can vary between eruptive events and post-emplacement alteration. In our samples, there is no clear relationship between alteration type and calculated radiolytic yields. Local maxima in U, Th, and K produce hotspots of H2 production, causing calculated radiolytic rates to differ by up to a factor of 80 from sample to sample. Fracture width also greatly influences H2 production, where microfractures are hotspots for radiolytic H2 production. For example, H2 production rates normalized to water volume are 190 times higher in 1 μm wide fractures than in fractures that are 10 cm wide. To assess the importance of water radiolysis for microbial communities in subseafloor basaltic aquifers, we compare electron transfer rates from radiolysis to rates from iron oxidation in subseafloor basalt. Radiolysis appears likely to be a more important electron donor source than iron oxidation in old (>10 Ma basement basalt. Radiolytic H2 production in the volume of water adjacent to a square cm of the most radioactive SPG basalt may

  16. Radiolytic Hydrogen Production in the Subseafloor Basaltic Aquifer

    Science.gov (United States)

    Dzaugis, Mary E.; Spivack, Arthur J.; Dunlea, Ann G.; Murray, Richard W.; D’Hondt, Steven

    2016-01-01

    Hydrogen (H2) is produced in geological settings by dissociation of water due to radiation from radioactive decay of naturally occurring uranium (238U, 235U), thorium (232Th) and potassium (40K). To quantify the potential significance of radiolytic H2 as an electron donor for microbes within the South Pacific subseafloor basaltic aquifer, we use radionuclide concentrations of 43 basalt samples from IODP Expedition 329 to calculate radiolytic H2 production rates in basement fractures. The samples are from three sites with very different basement ages and a wide range of alteration types. U, Th, and K concentrations vary by up to an order of magnitude from sample to sample at each site. Comparison of our samples to each other and to the results of previous studies of unaltered East Pacific Rise basalt suggests that significant variations in radionuclide concentrations are due to differences in initial (unaltered basalt) concentrations (which can vary between eruptive events) and post-emplacement alteration. However, there is no clear relationship between alteration type and calculated radiolytic yields. Local maxima in U, Th, and K produce hotspots of H2 production, causing calculated radiolytic rates to differ by up to a factor of 80 from sample to sample. Fracture width also greatly influences H2 production, where microfractures are hotspots for radiolytic H2 production. For example, H2 production rates normalized to water volume are 190 times higher in 1 μm wide fractures than in fractures that are 10 cm wide. To assess the importance of water radiolysis for microbial communities in subseafloor basaltic aquifers, we compare electron transfer rates from radiolysis to rates from iron oxidation in subseafloor basalt. Radiolysis appears likely to be a more important electron donor source than iron oxidation in old (>10 Ma) basement basalt. Radiolytic H2 production in the volume of water adjacent to a square cm of the most radioactive SPG basalt may support as many as

  17. Occurrence of nitrate in Tanzanian groundwater aquifers: A review

    Science.gov (United States)

    Elisante, Eliapenda; Muzuka, Alfred N. N.

    2015-03-01

    More than 25 % of Tanzanian depends on groundwater as the main source of water for drinking, irrigation and industrial activities. The current trend of land use may lead to groundwater contamination and thus increasing risks associated with the usage of contaminated water. Nitrate is one of the contaminants resulting largely from anthropogenic activities that may find its way to the aquifers and thus threatening the quality of groundwater. Elevated levels of nitrate in groundwater may lead to human health and environmental problems. The current trend of land use in Tanzania associated with high population growth, poor sanitation facilities and fertilizer usage may lead to nitrate contamination of groundwater. This paper therefore aimed at providing an overview of to what extent human activities have altered the concentration of nitrate in groundwater aquifers in Tanzania. The concentration of nitrate in Tanzanian groundwater is variable with highest values observable in Dar es Salaam (up to 477.6 mg/l), Dodoma (up to 441.1 mg/l), Tanga (above 100 mg/l) and Manyara (180 mg/l). Such high values can be attributed to various human activities including onsite sanitation in urban centres and agricultural activities in rural areas. Furthermore, there are some signs of increasing concentration of nitrate in groundwater with time in some areas in response to increased human activities. However, reports on levels and trends of nitrate in groundwater in many regions of the country are lacking. For Tanzania to appropriately address the issue of groundwater contamination, a deliberate move to determine nitrate concentration in groundwater is required, as well as protection of recharge basins and improvement of onsite sanitation systems.

  18. The hydrodynamic functioning of the deep aquifer of the Senegalese basin: An isotopic approach

    International Nuclear Information System (INIS)

    This work represents a synthesis of the main results obtained from the hydrochemical and isotopic study run within the IAEA project framework registered under SEN/8/005 'Hydrogeological study of the deep aquifer of the Maastrichtian'. The study has allowed a better understanding of the structure of the aquifer with the help of the new hydrochemical and isotopic data; a good understanding of the motion of ground water inside the aquifers and their impact on the mineralisation which is important for the water quality assessment

  19. Contribution to the study of Arapey Salto-Aquifer System (Department of Salto - Uruguay)

    International Nuclear Information System (INIS)

    This paper provide hydrogeological data about the Salto Arapey aquifer system constituted by sedimentary deposits and fisurate effusive rocks, respectively Tertiary and Cretacic aged. The information belongs to an area located at latitude South 31º20' West. North of the Salto city (NW of Uruguay) 500 km away from Montevideo. A regional aquifer system can be defined where the biggest flows are originated in the basaltic fisurate d rocks of the Arapey formation. Environment features are also considered and data about the main polluting agents - both organic and inorganic ones- are provided, bearing in mind that they justify an urgent safety design to protect the aquifer system

  20. Degradation of the Pesticides Mecoprop and Atrazine in Unpolluted Sandy Aquifers

    DEFF Research Database (Denmark)

    Klint, Mikala; Arvin, Erik; Jensen, Bjørn K.

    1993-01-01

    The potential for biodegradation of the pesticides mecoprop ((+/-)-2-(4-chloro-2-methyl-phenoxy)propionic acid) and atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) in an aerobic aquifer was investigated in laboratory batch experiments. The experiments were performed with groundwater...... the aquifer. Atrazine was not degraded during an incubation period of 539 d in groundwater and 174 d in suspensions of groundwater and aquifer sediment. The addition of nutrients, primary substrates (acetate and naphthalene), and a pH or temperature increase had not effect on the recalcitrance of atrazine....

  1. Alluvial aquifers in the Mzingwane catchment: Their distribution, properties, current usage and potential expansion

    Science.gov (United States)

    Moyce, William; Mangeya, Pride; Owen, Richard; Love, David

    The Mzingwane River is a sand filled channel, with extensive alluvial aquifers distributed along its banks and bed in the lower catchment. LandSat TM imagery was used to identify alluvial deposits for potential groundwater resources for irrigation development. On the false colour composite band 3, band 4 and band 5 (FCC 345) the alluvial deposits stand out as white and dense actively growing vegetation stands out as green making it possible to mark out the lateral extent of the saturated alluvial plain deposits using the riverine fringe and vegetation . The alluvial aquifers form ribbon shaped aquifers extending along the channel and reaching over 20 km in length in some localities and are enhanced at lithological boundaries. These alluvial aquifers extend laterally outside the active channel, and individual alluvial aquifers have been measured with area ranging from 45 ha to 723 ha in the channels and 75 ha to 2196 ha on the plains. The alluvial aquifers are more pronounced in the Lower Mzingwane, where the slopes are gentler and allow for more sediment accumulation. Estimated water resources potential ranges between 175,000 m 3 and 5,430,000 m 3 in the channels and between 80,000 m 3 and 6,920,000 m 3 in the plains. Such a water resource potential can support irrigation ranging from 18 ha to 543 ha for channels alluvial aquifers and 8 ha to 692 ha for plain alluvial aquifers. Currently, some of these aquifers are being used to provide water for domestic use, livestock watering and dip tanks, commercial irrigation and market gardening. The water quality of the aquifers in general is fairly good due to regular recharge and flushing out of the aquifers by annual river flows and floodwater. Water salinity was found to increase significantly in the end of the dry season, and this effect was more pronounced in water abstracted from wells on the alluvial plains. During drought years, recharge is expected to be less and if the drought is extended water levels in the

  2. Water Conservation Policy Alternatives for the Ogallala Aquifer in the Texas Panhandle

    OpenAIRE

    TAYLOR, Robert H.; Almas, Lal K.; Lust, David G.

    2009-01-01

    The continued decline in the availability of water from the Ogallala Aquifer has led to an increased interest in conservation policies designed to extend the life of the aquifer to sustain rural economies in the Texas Panhandle. This study evaluates the effectiveness of five policies in terms of changes in the saturated thickness of the aquifer as well as the impact each policy has on crop mix, water use per acre, and the net present value of farm profits over a sixty-year planning horizon fo...

  3. Ground-water flow and quality in Wisconsin's shallow aquifer system

    Science.gov (United States)

    Kammerer, P.A.

    1995-01-01

    The areal concentration distribution of commonmineral constituents and properties of ground water in Wisconsin's shallow aquifer system are described in this report. Maps depicting the water quality and the altitude of the water table are included. The shallow aquifer system in Wisconsin, composed of unconsolidated sand and gravel and shallow bedrock, is the source of most potable ground-water supplies in the State. Most ground water in the shallow aquifer system moves in local flow systems, but it interacts with regional flow systems in some areas.

  4. Regional modelling of the confined aquifers below the Boom clay in NE-Belgium

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. In the framework of the Belgian research program on the long term management of high-level and/or long-lived radioactive waste coordinated by ONDRAF/NIRAS, the Boom Clay is considered as a reference host rock for the geological disposal of high-level radioactive waste in NE-Belgium (Campine area). The hydrogeological program at SCK.CEN supports the long-term performance assessments of the geological disposal of radioactive waste by performing a phenomenological research of the aquifer systems surrounding the studied disposal system. One of the important components of this programme is the regional hydrogeological modelling. The regional hydrogeology is studied using two main models - the steady state Neogene aquifer model (NAM) and the transient deep aquifer pumping model (DAP), developed to characterize and quantify the regional groundwater flow in, respectively, the aquifers lying above the Boom Clay in the Nete catchment area (NAM), and the aquifers lying below the Boom Clay in the Campine area (DAP). This paper describes the most recent update of the DAP model. The DAP model represents the confined part of the groundwater system located stratigraphically below the Boom Clay. This includes the parts of the Oligocene aquifer, the Bartoon aquitard system and the Ledo-Paniselian-Brusselian aquifer buried under the Boom Clay. Due to the considerable pumping from these aquifers in combination with a limited recharge, a gradual decrease in groundwater levels has been observed in more than 30-year piezometric records. In the DAP model, the shallow aquifer system overlying the Boom Clay is replaced by fixed head boundaries: this aquifer system is dominated by close-to-surface hydrological processes and the heads fluctuate seasonally without any apparent long-term trend. In the horizontal direction, the model extends to the south as far as the outcrops of the major aquitards: the Maldegem Formation confining the Ledo

  5. Aquifers and hyporheic zones: Towards an ecological understanding of groundwater

    Science.gov (United States)

    Hancock, Peter J.; Boulton, Andrew J.; Humphreys, William F.

    2005-03-01

    Ecological constraints in subsurface environments relate directly to groundwater flow, hydraulic conductivity, interstitial biogeochemistry, pore size, and hydrological linkages to adjacent aquifers and surface ecosystems. Groundwater ecology has evolved from a science describing the unique subterranean biota to its current form emphasising multidisciplinary studies that integrate hydrogeology and ecology. This multidisciplinary approach seeks to elucidate the function of groundwater ecosystems and their roles in maintaining subterranean and surface water quality. In aquifer-surface water ecotones, geochemical gradients and microbial biofilms mediate transformations of water chemistry. Subsurface fauna (stygofauna) graze biofilms, alter interstitial pore size through their movement, and physically transport material through the groundwater environment. Further, changes in their populations provide signals of declining water quality. Better integrating groundwater ecology, biogeochemistry, and hydrogeology will significantly advance our understanding of subterranean ecosystems, especially in terms of bioremediation of contaminated groundwaters, maintenance or improvement of surface water quality in groundwater-dependent ecosystems, and improved protection of groundwater habitats during the extraction of natural resources. Overall, this will lead to a better understanding of the implications of groundwater hydrology and aquifer geology to distributions of subsurface fauna and microbiota, ecological processes such as carbon cycling, and sustainable groundwater management. Les contraintes écologiques dans les environnements de subsurface sont en relation directe avec les écoulements des eaux souterraines, la conductivité hydraulique, la biogéochimie des milieux interstitiels, la taille des pores, et les liens hydrologiques avec les aquifères et les écosystèmes adjacents. L'écologie des eaux souterraines a évolué d'une science décrivant uniquement les

  6. Aquifers and hyporheic zones: Towards an ecological understanding of groundwater

    Science.gov (United States)

    Hancock, Peter J.; Boulton, Andrew J.; Humphreys, William F.

    2005-03-01

    Ecological constraints in subsurface environments relate directly to groundwater flow, hydraulic conductivity, interstitial biogeochemistry, pore size, and hydrological linkages to adjacent aquifers and surface ecosystems. Groundwater ecology has evolved from a science describing the unique subterranean biota to its current form emphasising multidisciplinary studies that integrate hydrogeology and ecology. This multidisciplinary approach seeks to elucidate the function of groundwater ecosystems and their roles in maintaining subterranean and surface water quality. In aquifer-surface water ecotones, geochemical gradients and microbial biofilms mediate transformations of water chemistry. Subsurface fauna (stygofauna) graze biofilms, alter interstitial pore size through their movement, and physically transport material through the groundwater environment. Further, changes in their populations provide signals of declining water quality. Better integrating groundwater ecology, biogeochemistry, and hydrogeology will significantly advance our understanding of subterranean ecosystems, especially in terms of bioremediation of contaminated groundwaters, maintenance or improvement of surface water quality in groundwater-dependent ecosystems, and improved protection of groundwater habitats during the extraction of natural resources. Overall, this will lead to a better understanding of the implications of groundwater hydrology and aquifer geology to distributions of subsurface fauna and microbiota, ecological processes such as carbon cycling, and sustainable groundwater management. Les contraintes écologiques dans les environnements de subsurface sont en relation directe avec les écoulements des eaux souterraines, la conductivité hydraulique, la biogéochimie des milieux interstitiels, la taille des pores, et les liens hydrologiques avec les aquifères et les écosystèmes adjacents. L'écologie des eaux souterraines a évolué d'une science décrivant uniquement les

  7. Preliminary study of the aquifers of the lower Mesilla Valley in Texas and New Mexico by model simulation

    Science.gov (United States)

    Gates, J.S.; White, D.E.; Leggat, E.R.

    1984-01-01

    The aquifers in the lower Mesilla Valley of Texas and New Mexico provide water for irrigation, industrial use, and municipal supply. The shallow aquifer principally is used for irrigation. The medium-depth aquifer and deep aquifer are used by the city of El Paso for municipal supply, about 120,000 acre-feet per year in 1975. The potential use of the medium-depth and deep aquifers for irrigation, together with a planned increase in pumping by the city, is causing concern about the impact of this development. A three-dimensional digital model of the aquifers was developed to evaluate the responses of water levels to various schemes of development, with particular emphasis on the medium-depth and deep aquifers in and near the Canutillo well field. The model simulations indicate that if pumpage increases to 10,000 acre-feet per year from the medium-depth aquifer and to 20,000 acre-feet per year from the deep aquifer, and elsewhere is constant, then additional lowering of water levels would be as much as 24 feet in the medium-depth aquifer and as much as 52 feet in the deep aquifer. The water levels would decline sharply during the first few months, after which the levels would become nearly stable because the leakage between the aquifers probably is enough to balance the increased pumpage. The model also indicated that lining of the channel of the Rio Grande would result in an additional lowering of water levels by 10 feet in the medium-depth aquifer and 8 feet in the deep aquifer. (USGS)

  8. Survey of groundwater isotopic composition (δ2H and δ18O) from the southwestern Edwards Aquifer and regionally associated aquifers

    Science.gov (United States)

    West, J. B.; Shallock, J. R.; Cooper, R.

    2009-12-01

    Aquifers are an important source of water for growing human populations, while they also support numerous critical ecosystem functions, including supplying water to springs and rivers necessary for terrestrial and aquatic ecosystems and the sometimes endangered species that are part of them. As human populations increase and the climate changes, demands on aquifer resources will continue to increase. To support these growing populations, urban areas in particular seek to develop additional water resources with, in some cases, not well-understood impacts on interconnected aquifers as well as the terrestrial and aquatic ecosystems that depend on spring-fed surface water. In addition, large-scale changes to terrestrial systems (e.g., removal of woody vegetation) can be motivated by a desire to enhance aquifer recharge, but an understanding of the effect of those efforts on the regional water cycle is hampered, in part, by a lack of detailed understanding of the interactions of various features below ground. It is critical therefore to understand the relationships between waters found in different formations, as well as among surface and ground waters to improve our understanding of the consequences of increasing human demands and the impacts of climate change. We have conducted a survey of wells in south central Texas that access major and minor aquifers, including the karst-type Edwards (BFZ) aquifer and several regional minor aquifers. The primary objective of this survey was to establish baseline information from which to develop further targeted research using event-based sampling and a range of additional data on precipitation, geology, and other spatially explicit information. We sampled multiple wells in an area west of San Antonio, TX that access the primary major and minor aquifers in the region. The isotopic compositions of water taken from these wells at various locations and depths were similar, suggesting that these aquifers experience significant mixing

  9. Conceptual understanding and groundwater quality of selected basin-fill aquifers in the Southwestern United States

    Science.gov (United States)

    Thiros, Susan A.; Bexfield, Laura M.; Anning, David W.; Huntington, Jena M.

    2010-01-01

    The National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey has been conducting a regional analysis of water quality in the principal aquifer systems in the southwestern United States (hereinafter, 'Southwest') since 2005. Part of the NAWQA Program, the objective of the Southwest Principal Aquifers (SWPA) study is to develop a better understanding of water quality in basin-fill aquifers in the region by synthesizing information from case studies of 15 basins into a common set of important natural and human-related factors found to affect groundwater quality. The synthesis consists of three major components: 1. Summary of current knowledge about the groundwater systems, and the status of, changes in, and influential factors affecting quality of groundwater in basin-fill aquifers in 15 basins previously studied by NAWQA (this report). 2. Development of a conceptual model of the primary natural and human-related factors commonly affecting groundwater quality, thereby building a regional understanding of the susceptibility and vulnerability of basin-fill aquifers to contaminants. 3. Development of statistical models that relate the concentration or occurrence of specific chemical constituents in groundwater to natural and human-related factors linked to the susceptibility and vulnerability of basin-fill aquifers to contamination. Basin-fill aquifers occur in about 200,000 mi2 of the 410,000 mi2 SWPA study area and are the primary source of groundwater supply for cities and agricultural communities. Four of the principal aquifers or aquifer systems of the United States are included in the basin-fill aquifers of the study area: (1) the Basin and Range basin-fill aquifers in California, Nevada, Utah, and Arizona; (2) the Rio Grande aquifer system in New Mexico and Colorado; (3) the California Coastal Basin aquifers; and (4) the Central Valley aquifer system in California. Because of the generally limited availability of surface-water supplies in

  10. Unravelling aquifer-wetland interaction using CSAMT and gravity methods: the Mollina-Camorra aquifer and the Fuente de Piedra playa-lake, southern Spain

    Science.gov (United States)

    Pedrera, A.; Martos-Rosillo, S.; Galindo-Zaldívar, J.; Rodríguez-Rodríguez, M.; Benavente, J.; Martín-Rodríguez, J. F.; Zúñiga-López, M. I.

    2016-06-01

    The hydrological regime of Fuente de Piedra playa-lake (Málaga, southern Spain) has been significantly affected by the intensive exploitation of groundwater in the area. The playa-lake is situated above clays, marls, and gypsum, and under unaltered conditions received surface-subsurface runoff within the watershed as well as groundwater discharge from two carbonate aquifers. We have analyzed the structure of the main one, the Mollina-Camorra carbonate aquifer, by combining controlled source audio magnetotellurics (CSAMT), gravity prospecting, and time-domain electromagnetic (TDEM) soundings. This geophysical information, together with new structural and hydrogeological data, was gathered to develop a new conceptual hydrogeological model. This model allows the hydrological linkage of the carbonate aquifer with the playa-lake system to be established. Moreover, the intensive exploitation in the carbonate aquifer, even outside the watershed of the playa-lake, has affected the hydrological regime of the system. This multidisciplinary work demonstrates the potential of geophysical methods for understanding wetland-aquifer interaction, having important groundwater management implications.

  11. Hydrogeological analysis of the upper Dupi Tila Aquifer, towards the implementation of a managed aquifer-recharge project in Dhaka City, Bangladesh

    Science.gov (United States)

    Rahman, Mohammad Azizur; Wiegand, Bettina A.; Badruzzaman, A. B. M.; Ptak, Thomas

    2013-08-01

    A preliminary feasibility assessment of managed aquifer-recharge (MAR) techniques was undertaken for Dhaka City, Bangladesh. Considering the top impermeable-layer (TIL) thickness and the land-use classification, four primary MAR techniques have been suggested: (1) soil-aquifer treatment (SAT) for TIL thickness 0-8 m, (2) cascade-type recharge trenches/pits for TIL thickness 9-30 m, (3) aquifer storage, transfer and recovery (ASR/ASTR) for TIL thickness 31-52 m, and (4) use of natural wetlands to recharge water collected from open spaces. The study suggests that recharge trenches and pits will be the most appropriate MAR techniques, which can be implemented in most parts of the recharge area (ca. 277 km2). In case of a recharge trench, the lower parts (15-20 m) that are in direct contact with the aquifer can be backfilled with biosand filters with a reactive layer containing metallic iron (Fe0) to offer pre-treatment of the infiltrated water. In addition to the suggested four techniques, the regional groundwater flow direction, from the northwest and northeast towards Dhaka City, may allow use of the aquifer as a natural treatment and transport medium for groundwater, if spreading basins are installed in the greater Dhaka area.

  12. Arsenic release from shallow aquifers of the Hetao Basin, Inner Mongolia: Evidence from bacterial community in aquifer sediments and groundwater

    Science.gov (United States)

    Li, Y.; Guo, H.

    2013-12-01

    Indigenous microbes play crucial roles in arsenic mobilization in high arsenic groundwater systems. Databases concerning the presence and the activity of microbial communities are very useful in evaluating the potential of microbe-mediated arsenic mobilization in shallow aquifers hosting high arsenic groundwater. This study characterized microbial communities in groundwaters at different depths with different arsenic concentrations by DGGE and one sediment by 16S rDNA gene clone library, and evaluated arsenic mobilization in microcosm batches with the presence of indigenous bacteria. DGGE fingerprints revealed that the community structure changed substantially with depth at the same location. It indicated that a relatively higher bacterial diversity was present in the groundwater sample with lower arsenic concentration. The clone library of sediment sample 2009M1 and DGGE profiles of microbial community structures of groundwater samples indicated NO3-, Fe(III) and SO42- reducing bacteria are abundant in the As-affected aquifer, which are facultative or anaerobic chemoautotrophic bacteria. Pseudomonas that was rich in both high arsenic groundwater and sediment included a great number of denitrifying bacterium strains that may contribute to the low concentration of nitrate in the groundwater. Fe(III)-reducing bacteria belonging to different species, such as Aquabacterium sp., Thauera sp., Georgfuchsia sp., Methyloversatilis sp., Clostridium sp., were widely found in the community. The genus Desulfosporosinus observed in the sediment sample of 2009M1 was believed to be sulfate reducer. These results offered direct evidences that anaerobic reducing bacteria play a role in the formation of toxic, mobile As(III) in the groundwater of the Hetao basin, especially Fe(III)-reducing bacteria. Incubation of sediments without the addition of organic carbon source showed a significant release of arsenic (predominantly as As(III)). By contrast, sterile incubations and incubations

  13. Framework for regional synthesis of water-quality data for the glacial aquifer system in the United States

    Science.gov (United States)

    Warner, Kelly L.; Arnold, Terri L.

    2005-01-01

    The glacial aquifer system is the largest principal aquifer in aerial extent and ground-water use for public supply in the United States. A principal aquifer is defined as a regionally extensive aquifer or aquifer system that has the potential to be used as a source of potable water (U.S. Geological Survey, 2003). Multiple aquifers often are grouped into large, extensive aquifer systems such as the glacial aquifer system. The glacial aquifer system is considered here to include all unconsolidated aquifers above bedrock north of the line of continental glaciation throughout the country (fig. 1). Total withdrawals from the glacial aquifer system were 3,560 million gallons per day in 2000, which constitutes almost 5 percent of total withdrawals from all aquifers in the United States (Maupin and Barber, 2005). Approximately 41 million people relied on the glacial aquifer for public supply and domestic use in 2000. The U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program began assessing the glacial aquifer system in 1991. The assessment of water-quality data on a regional scale, such as the glacial aquifer system, is coincident with the regional framework established by the Regional Aquifer-System Analysis Program (RASA) (Sun and others, 1997). From 1978 to 1995, the RASA Program systematically evaluated 25 of the Nation's most important groundwater systems including studies in the glacial aquifer system in the northeast, Midwest, and northern Midwest United States. The NAWQA Program is building on the work of the RASA Program to study the water quality of 16 of the most important ground-water systems (Lapham and others, 2005). Over 1,700 water-quality samples have been collected by the NAWQA Program from 1991 to 2004 to assess the glacial aquifer system. This large data set is unique in that the samples have been collected using a consistent sampling protocol, and multiple nested samples. The nested samples address the recently recharged shallow

  14. Three-dimensional conceptual model for the Hanford Site unconfined aquifer system: FY 1994 status report

    Energy Technology Data Exchange (ETDEWEB)

    Thorne, P.D.; Chamness, M.A.; Vermeul, V.R.; Macdonald, Q.C.; Schubert, S.E.

    1994-11-01

    This report documents work conducted during the fiscal year 1994 to development an improved three-dimensional conceptual model of ground-water flow in the unconfined aquifer system across the Hanford Site Ground-Water Surveillance Project, which is managed by Pacific Northwest Laboratory. The main objective of the ongoing effort to develop an improved conceptual model of ground-water flow is to provide the basis for improved numerical report models that will be capable of accurately predicting the movement of radioactive and chemical contaminant plumes in the aquifer beneath Hanford. More accurate ground-water flow models will also be useful in assessing the impacts of changes in facilities and operations. For example, decreasing volumes of operational waste-water discharge are resulting in a declining water table in parts of the unconfined aquifer. In addition to supporting numerical modeling, the conceptual model also provides a qualitative understanding of the movement of ground water and contaminants in the aquifer.

  15. Investigation of a shallow aquifer near the Fenton Hill hot dry rock site using DC resistivity

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, C.F.

    1981-10-01

    A shallow aquifer in the base of the Tertiary volcanic sequence was investigated using a series of 9 DC Schlumberger soundings taken within 10 km of the Fenton Hill hot dry rock geothermal site. The aquifer dips to the southwest following the top of the Abo formation, which acts as an aquiclude. Depth increases from 130 m in the eastern part of the study area to 260 m at 1.5 km west of the Fenton Hill site. Aquifer resistivities varied from 13..cap omega..-m to 126..cap omega..-m, which could be caused by variable permeability in the aquifer. Using results from empirical studies permeabilities ranging from 40 darcies to less than 0.3 darcies were estimated with the highest values occurring nearest to the Fenton Hill site.

  16. Altitude of the top of the Lower Hell Creek aquifer in the Williston structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the altitude, in feet above North American Vertical Datum of 1988 (NAVD88), of the Lower Hell Creek aquifer in the Williston structural basin....

  17. Thickness of the Lower Hell Creek aquifer in the Williston structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the thickness, in feet, of the Lower Hell Creek aquifer in the Williston structural basin. The data are presented as ASCII text files that can...

  18. Project Summary. IN-SITU AQUIFER RESTORATION OF CHLORINATED ALIPHATICS BY METHANOTROPHIC BACTERIA

    Science.gov (United States)

    This project evaluated the potential of an innovative approach to aquifer restoration: enhanced in-situ biotransformation of chlorinated aliphatic solvents by a bacterial community grown on methane under aerobic conditions. The target chlorinated compounds were trichloroethene (...

  19. Mississippi River Valley Alluvial Aquifer, Alabama, Arkansas, Illinois, Kentucky, Louisiana, Mississippi, Tennessee; 2006-2008

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Outcrop and subcrop extent of the Mississippi River Valley Alluvial Aquifer in Alabama, Arkansas, Illinois, Kentucky, Louisiana, Mississippi, and Tennessee.

  20. Thickness of the Fox Hills aquifer in the Williston structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the thickness, in feet, of the Fox Hills aquifer in the Williston structural basin. The data are presented as ASCII text files that can be...

  1. Thickness of the lower Fort Union aquifer in the Powder River structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the thickness, in feet, of the lower Fort Union aquifer in the Powder River basin. The data are presented as ASCII text files that can be...

  2. Altitude of the top of the lower Fort Union aquifer in the Williston structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the altitude, in feet above North American Vertical Datum of 1988 (NAVD88), of the lower Fort Union aquifer in the Williston structural basin....

  3. Thickness of the upper Fort Union aquifer in the Williston structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the thickness, in feet, of the upper Fort Union aquifer in the Williston structural basin. The data are presented as ASCII text files that can...

  4. Thickness of the lower Fort Union aquifer in the Williston structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the thickness, in feet, of the lower Fort Union aquifer in the Williston structural basin. The data are presented as ASCII text files that can...

  5. Altitude of the top of the upper Fort Union aquifer in the Powder River structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the altitude, in feet above North American Vertical Datum of 1988 (NAVD88), of the upper Fort Union aquifer in the Powder River basin. The data...

  6. Altitude of the top of the upper Fort Union aquifer in the Williston structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the altitude, in feet above North American Vertical Datum of 1988 (NAVD88), of the upper Fort Union aquifer in the Williston structural basin....

  7. Altitude of the top of the lower Fort Union aquifer in the Powder River structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the altitude, in feet above North American Vertical Datum of 1988 (NAVD88), of the lower Fort Union aquifer in the Powder River basin. The data...

  8. Thickness of the upper Fort Union aquifer in the Powder River structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the thickness, in feet, of the upper Fort Union aquifer in the Powder River basin. The data are presented as ASCII text files that can be...

  9. Altitude of the top of the Fox Hills aquifer in the Williston structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the altitude, in feet above North American Vertical Datum of 1988 (NAVD88), of the Fox Hills aquifer in the Williston structural basin. The...

  10. Superfund GIS - Physiographic Provinces, Aquifer Outcrops and Recharge Rates in Tennessee

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset is a coverage of the physiographic provinces, aquifer outcrops and recharge rates for Tennessee. Each polygon is attributed with its associated...

  11. Principal aquifers of Puerto Rico and the U.S. Virgin Islands

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This is polygon data of shallowest principal aquifers of Puerto Rico and the United States Virgin Islands, developed as part of the effort to produce a map...

  12. Environmental assessment of the potential effects of aquifer thermal energy storage systems on microorganisms in groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Hicks, R.J.; Stewart, D.L.

    1988-03-01

    The primary objective of this study was to evaluate the potential environmental effects (both adverse and beneficials) of aquifer thermal energy storage (ATES) technology pertaining to microbial communities indigenous to subsurface environments (i.e., aquifers) and the propagation, movement, and potential release of pathogenic microorganisms (specifically, Legionella) within ATES systems. Seasonal storage of thermal energy in aquifers shows great promise to reduce peak demand; reduce electric utility load problems; contribute to establishing favorable economics for district heating and cooling systems; and reduce pollution from extraction, refining, and combustion of fossil fuels. However, concerns that the widespread implementation of this technology may have adverse effects on biological systems indigeneous to aquifers, as well as help to propagate and release pathogenic organisms that enter thee environments need to be resolved. 101 refs., 2 tabs.

  13. Depth to water in the High Plains Aquifer in Colorado, 2000.

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data are in support of report DS 456 (Arnold and others, 2009). This grid represents the depth to groundwater in the High Plains Aquifer in Colorado in 2000....

  14. Preliminary Report for the location of drilling in the Raigon aquifer area

    International Nuclear Information System (INIS)

    This work is about the geological and hydrogeological characteristics of Santa Lucia basin belongs to the Raison Aquifer. The tectonic basin of Santa Lucia is a structural complex constituted by the crystalline basement, gneisses, amphibolite s, mica schists and metamorfites

  15. Regional flow and deformation analysis of Basin-fill aquifer systems using stress-dependent parameters.

    Science.gov (United States)

    Preisig, Giona; Cornaton, Fabien Joel; Perrochet, Pierre

    2014-01-01

    Changes in effective stress due to water pressure variations modify the intrinsic hydrodynamic properties of aquifers and aquitards. Overexploited groundwater systems, such as basins with heavy pumping, are subject to nonrecoverable modifications. This results in loss of permeability, porosity, and specific storage due to system consolidation. This paper presents (1) the analytical development of model functions relating effective stress to hydrodynamic parameters for aquifers and aquitards constituted of unconsolidated granular sediments, and (2) a modeling approach for the analysis of aquifer systems affected by effective stress variations, taking into account the aforementioned dependency. The stress-dependent functions were fit to laboratory data, and used in the suggested modeling approach. Based on only few unknowns, this approach is computationally simple, efficiently captures the hydromechanical processes that are active in regional aquifer systems under stress, and readily provides an estimate of their consolidation. PMID:23448260

  16. Middle Wilcox Aquifer: Alabama, Arkansas, Illinois, Kentucky, Louisiana, Missouri, Mississippi, Tennessee 2006-2008

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Digital hydrogeologic surface of the Middle Wolcox Aquifer in Alabama, Arkansas, Illinois, Kentucky, Louisiana, Missouri, Mississippi, Tennessee. The hydrogeologic...

  17. Origin and structures of groundwater humic substances from three Danish aquifers

    DEFF Research Database (Denmark)

    Grøn, C.; Wassenaar, L.; Krog, M.

    1996-01-01

    Structural, chemical, and isotopic parameters were used to identify the origins of groundwater humic substances from three Danish aquifers. A variety of analytical techniques (visible light absorption, molecular weight distribution, C-13-NMR spectroscopy, elemental composition with major elements...

  18. Upper Claiborne Aquifer: Alabama, Arkansas, Louisiana, Missouri, Mississippi, Tennessee 2006-2008

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Digital hydrogeologic surface of the Upper Claiborne Aquifer in Arkansas, Alabama, Louisiana, Missouri, Mississippi, and Tennessee. The hydrogeologic unit dataset...

  19. MICROBIAL COMMUNITY STRUCTURE IN A SHALLOW HYDROCARBON-CONTAMINATED AQUIFER ASSOCIATED WITH HIGH ELECTRICAL CONDUCTIVITY

    Science.gov (United States)

    Little is known about the complex interactions between microbial communities and electrical properties in contaminated aquifers. In order to investigate possible connections between these parameters a study was undertaken to investigate the hypothesis that the degradation of hydr...

  20. Estimated Thickness of Quaternary Sediment in the Wood River Valley aquifer system, South-Central Idaho

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset is the estimated thickness of Quaternary sediment of the Wood River Valley aquifer system. This isopach map was constructed by subtracting the...

  1. Soil Aquifer Treatment: Assessment and Applicability of Primary Effluent Reuse in Developing Countries

    NARCIS (Netherlands)

    Abel, C.D.T.

    2014-01-01

    This thesis showed that soil aquifer treatment (SAT) is an effective polishing technology for reuse of primary effluent. The study experimentally revealed relatively high removal of suspended solids, bulk organic matter, nutrients, pharmaceutically active compounds and pathogens indicators under var

  2. Thickness of the glacial aquifer system in the Williston structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the thickness, in feet, of the glacial aquifer system in the Williston structural basin. The data are presented as ASCII text files that can be...

  3. A new approach for assessing the future of aquifers supporting irrigated agriculture

    Science.gov (United States)

    Butler, James J.; Whittemore, Donald O.; Wilson, Blake B.; Bohling, Geoffrey C.

    2016-03-01

    Aquifers supporting irrigated agriculture are under stress worldwide as a result of large pumping-induced water deficits. To aid in the formulation of more sustainable management plans for such systems, we have developed a water balance approach for assessing the impact of proposed management actions and the prospects for aquifer sustainability. Application to the High Plains aquifer (HPA) in the state of Kansas in the United States reveals that practically achievable reductions in annual pumping (HPA from 1996 to 2013. This demonstrates that modest pumping reductions can have a significant impact and highlights the importance of reliable pumping data for determining the net inflow (capture) component of the water balance. The HPA is similar to many aquifers supporting critically needed agricultural production, so the presented approach should prove of value far beyond the area of this initial application.

  4. Water‐Data Report Grassy Island Undefined Aquifer Detroit River International Wildlife Refuge - 2014

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Grassy Island near Ecorse, MI Undefined Aquifer Detroit River International Wildlife Refuge, Michigan. Datum of records is Land surface and top of casing datum is...

  5. Hydrogeology and simulation of groundwater flow in the Arbuckle-Simpson aquifer, south-central Oklahoma

    Science.gov (United States)

    Christenson, Scott; Osborn, Noel I.; Neel, Christopher R.; Faith, Jason R.; Blome, Charles D.; Puckette, James; Pantea, Michael P.

    2011-01-01

    The Arbuckle-Simpson aquifer in south-central Oklahoma provides water for public supply, farms, mining, wildlife conservation, recreation, and the scenic beauty of springs, streams, and waterfalls. Proposed development of water supplies from the aquifer led to concerns that large-scale withdrawals of water would cause decreased flow in rivers and springs, which in turn could result in the loss of water supplies, recreational opportunities, and aquatic habitat. The Oklahoma Water Resources Board, in collaboration with the Bureau of Reclamation, the U.S. Geological Survey, Oklahoma State University, and the University of Oklahoma, studied the aquifer to provide the Oklahoma Water Resources Board the scientific information needed to determine the volume of water that could be withdrawn while protecting springs and streams. The U.S. Geological Survey, in coopertion with the Oklahoma Water Resources Board, did a study to describe the hydrogeology and simulation of groundwater flow of the aquifer.

  6. Creation of a Digital Aquifer Permeability Map for the Pacific Northwest

    Science.gov (United States)

    Hydrologic classification systems can provide a basis for broadscale assessments of the hydrologic functions of landscapes and watersheds and their responses to stressors such as climate change. One of the greatest challenges to this effort is obtaining consistent aquifer permea...

  7. Water and sediment quality in habitat springs of Edwards Aquifer salamanders

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Many springs associated with the Edwards Aquifer of Texas are inhabited by relict populations of neotenic salamanders in the genus Eurycea. This study was done to...

  8. Methanogenesis in a shallow sandy aquifer, Rømø, Denmark

    DEFF Research Database (Denmark)

    Hansen, L.K.; Jakobsen, Rasmus; Postma, Diederik Jan

    2001-01-01

    The degradation of organic matter and the formation of methane were investigated in a shallow sandy aquifer. The aquifer was found to be anoxic from the water table downward; the upper 2 m contained sulfate and was enriched in Fe(II). Methane was present in the groundwater from 2 to 3 m below...... part of the aquifer, rates of acetate oxidation of up to 4 mM/yr were measured in the same zone where sulfate reduction and the reduction of iron oxides takes place. Total methane formation rates range from 0.1 to 4 mM/yr and proceeds through both the pathway of CO2 reduction and acetate fermentation....... CO2 reduction was found to be the dominant pathway, although in some cases acetate fermentation contributed up to 50% of the total methane formation rate. High spatial variation, both vertically and horizontally, in methane formation rates are a characteristic feature of this aquifer sediment...

  9. Large sedimentary aquifer systems functioning. Constraints by classical isotopic and chemical tools, and REE in the Eocene sand aquifer, SW France

    Science.gov (United States)

    Petelet-Giraud, E.; Negrel, P. J.; Millot, R.; Guerrot, C.; Brenot, A.; Malcuit, E.

    2010-12-01

    Large sedimentary aquifer systems often constitute strategic water resources for drinking water supply, agriculture irrigation and industry, but can also represent an energetic resource for geothermal power. Large water abstractions can induce complete modification of the natural functioning of such aquifer systems, e.g. with seepage between aquifer layers that can lead to water quality degradation. These large aquifer systems thus require rational water management at the sedimentary basin scale in order to preserve both water quantity and quality. In addition to hydrogeological modelling mainly dealing with water quantity, chemical and isotopic methods were applied to evidence the spatial variability of water characteristics and to turn this into better understanding of hydrosystems functioning. The large Eocene Sand aquifer system of the Adour-Garonne sedimentary basin was studied through various hydrological, chemical and isotopic tools. This system extends over 116,000 km2 (one-fifth of the French territory, located in the South west part). The aquifer being artesian in the west of the district and confined with piezometric levels around 250-m depth in the east. The ‘Eocene Sands’, composed of sandy Tertiary sediments alternating with carbonate deposits, is a multi-layer system with high permeability and a thickness of several tens of metres to a hundred metres..The Eocene Sand aquifer system comprises at least five aquifers: Paleocene, Eocene infra-molassic sands (IMS), early Eocene, middle Eocene, and late Eocene. According to δ18O and δ2H values and estimated 14C ages, both present-day recharge (mainly located in the north of the area) and old recharge (16-35 ky) can be evidenced. High spatial variability was evidenced within a same aquifer layer, with temporal variability over one hydrological cycle limited to a few points located in the recharge areas. These results and especially the very old waters recharged under colder climate combined with the

  10. Digital model of predevelopment flow in the Tertiary limestone (Floridan) aquifer system in West-Central Florida

    Science.gov (United States)

    Ryder, Paul D.

    1982-01-01

    A computer model was calibrated to approximate predevelopment flow conditions in a multilayered aquifer system in 10,600 square miles in west-central Floria. The lowermost aquifer, called the Floridan aquifer, is confined in most of the study area and consists of carbonate rocks ranging up to 1,300 feet thick. The Floridan aquifer is the chief source for large withdrawals and natural springflow in the study area. Daily springflows within the study area have averaged about 2.4 billion gallons. The secondary artesian and the surficial aquifers are much less permeable than the Floridan aquifer. Where they are present and have heads higher than those in the Floridan aquifer, they provide recharge to the Floridan. Initial estimates of recharge to the Floridan aquifer were from water-balance calculations for surface-water basins; initial estimates of transmissivity were from aquifer tests and flow-net analyses. The model was calibrated for the predevelopment era, wherein steady-state flow conditions were assumed. Calibrated transmissivities for the Floridan aquifer range from less than 15,000 to several million feet squared per day. Recharge to the system was about 3,700 cubic feet per second. About 90% was discharged as springflow, and 10% was upward leakage. (USGS)

  11. Seismic velocities to characterize the soil-aquifer continuum on the Orgeval experimental basin (France)

    Science.gov (United States)

    Pasquet, S.; Ludovic, B.; Dhemaied, A.; Flipo, N.; Guérin, R.; Mouhri, A.; Faycal, R.; Vitale, Q.

    2013-12-01

    Among geophysical methods applied to hydrogeology, seismic prospecting is frequently confined to the characterization of aquifers geometry. The combined study of pressure- (P) and shear- (SH) wave velocities (respectively Vp and Vs) can however provide information about the aquifer parameters, as it is commonly done for most fluids in hydrocarbon exploration. This approach has recently been proposed in sandy aquifers with the estimation of Vp/Vs ratio. In order to address such issues in more complex aquifer systems (e.g. unconsolidated, heterogeneous or low-permeability media) we carried out P- and SH-wave seismic surveys on the Orgeval experimental basin (70 km east from Paris, France). This basin drains a multi-layer aquifer system monitored by a network of piezometers. The upper part of the aquifer system is characterized by tabular layers well delineated all over the basin thanks to Electrical Resistivity Tomography (ERT), Time Domain ElectroMagnetic (TDEM) soundings and wells. But the lateral variability of the intrinsic properties in each layer raises questions regarding the hydrodynamics of the upper aquifer and the validity of interpolations between piezometers. A simple interpretation of P- and SH-wave first arrivals for tabular models provides 1D velocity structures in very good agreement with the stratification anticipated from ERT and nearby geological logs. Vp/Vs ratios show a strong contrast at a depth consistent with the observed water table level, reinforcing the assumption of a free upper aquifer in the area. Similar experiments have to be conducted under different hydrological conditions to validate these observations. Anticipating the need to propose lateral applications of the method, we additionally performed tomographic inversions of the recorded data to retrieve 2D Vp and Vs models. If interpreted independently, both models fail to depict the stratification of the medium and the water table level cannot be straightforwardly identified

  12. Extrapolation of biodegradation results to groundwater aquifers: reductive dehalogenation of aromatic compounds.

    OpenAIRE

    Gibson, S. A.; Suflita, J M

    1986-01-01

    The reductive biodegradation of a variety of haloaromatic substrates was monitored in samples from two sites within a shallow anoxic aquifer and was compared with freshwater sediment and sewage sludge. The metabolic capacity existing in methane-producing aquifer material was very similar to that in sediment in that three of four chlorobenzoates, five of seven chlorophenols, and one of two chlorophenoxyacetate herbicides were reductively dehalogenated in both types of incubations. The 2,4-dich...

  13. Effects of Barometric Fluctuations on Well Water-Level Measurements and Aquifer Test Data

    Energy Technology Data Exchange (ETDEWEB)

    FA Spane, Jr.

    1999-12-16

    The Pacific Northwest National Laboratory, as part of the Hanford Groundwater Monitoring Project, examines the potential for offsite migration of contamination within underlying aquifer systems. Well water-level elevation measurements from selected wells within these aquifer systems commonly form the basis for delineating groundwater-flow patterns (i.e., flow direction and hydraulic gradient). In addition, the analysis of water-level responses obtained in wells during hydrologic tests provides estimates of hydraulic properties that are important for evaluating groundwater-flow velocity and transport characteristics. Barometric pressure fluctuations, however, can have a discernible impact on well water-level measurements. These barometric effects may lead to erroneous indications of hydraulic head within the aquifer. Total hydraulic head (i.e., sum of the water-table elevation and the atmospheric pressure at the water-table surface) within the aquifer, not well water-level elevation, is the hydrologic parameter for determining groundwater-flow direction and hydraulic gradient conditions. Temporal variations in barometric pressure may also adversely affect well water-level responses obtained during hydrologic tests. If significant, adjustments or removal of these barometric effects from the test-response record may be required for quantitative hydraulic property determination. This report examines the effects of barometric fluctuations on well water-level measurements and evaluates adjustment and removal methods for determining areal aquifer head conditions and aquifer test analysis. Two examples of Hanford Site unconfined aquifer tests are examined that demonstrate barometric response analysis and illustrate the predictive/removal capabilities of various methods for well water-level and aquifer total head values. Good predictive/removal characteristics were demonstrated with best corrective results provided by multiple-regression deconvolution methods.

  14. Transport behavior of groundwater protozoa and protozoan-sized microspheres in sandy aquifer sediments

    Science.gov (United States)

    Harvey, R.W.; Kinner, N.E.; Bunn, A.; MacDonald, D.; Metge, D.

    1995-01-01

    Transport behaviors of unidentified flagellated protozoa (flagellates) and flagellate-sized carboxylated microspheres in sandy, organically contaminated aquifer sediments were investigated in a small-scale (1 to 4-m travel distance) natural-gradient tracer test on Cape Cod and in flow-through columns packed with sieved (0.5-to 1.0-mm grain size) aquifer sediments. The minute (average in situ cell size, 2 to 3 ??m) flagellates, which are relatively abundant in the Cape Cod aquifer, were isolated from core samples, grown in a grass extract medium, labeled with hydroethidine (a vital eukaryotic stain), and coinjected into aquifer sediments along with bromide, a conservative tracer. The 2-??m flagellates appeared to be near the optimal size for transport, judging from flowthrough column experiments involving a polydispersed (0.7 to 6.2 ??m in diameter) suspension of carboxylated microspheres. However, immobilization within the aquifer sediments accounted for a log unit reduction over the first meter of travel compared with a log unit reduction over the first 10 m of travel for indigenous, free-living groundwater bacteria in earlier tests. High rates of flagellate immobilization in the presence of aquifer sediments also was observed in the laboratory. However, immobilization rates for the laboratory-grown flagellates (initially 4 to 5 ??m) injected into the aquifer were not constant and decreased noticeably with increasing time and distance of travel. The decrease in propensity for grain surfaces was accompanied by a decrease in cell size, as the flagellates presumably readapted to aquifer conditions. Retardation and apparent dispersion were generally at least twofold greater than those observed earlier for indigenous groundwater bacteria but were much closer to those observed for highly surface active carboxylated latex microspheres. Field and laboratory results suggest that 2- ??m carboxylated microspheres may be useful as analogs in investigating several abiotic

  15. Advective heat transport in the upper carbonate aquifer beneath Winnipeg, Manitoba

    Energy Technology Data Exchange (ETDEWEB)

    Ferguson, G.A.G.; Woodbury, A.D. [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Civil Engineering

    2003-07-01

    Air conditioning and industrial cooling in Winnipeg, Manitoba requires large volumes of groundwater, with the bulk of this water pumped from the Upper Carbonate Aquifer. Pumping takes place at the erosional surface of several dipping Paleozoic carbonate units beneath the city. To prevent excessive drawdown, wastewater from these processes is reinjected into the aquifer. Heat loading from the surface, combined with this practice, leads to the creation of areas of elevated temperature within the Upper Carbonate Aquifer. An industrial area located in eastern Winnipeg is the site of the largest of these anomalies, where the aquifer's permeability is enhanced by the presence of conduits and discrete fractures. The use of numerical modeling showed that the greatest temperature anomalies occur where there are very high permeabilities, especially in the form of conduits and discrete fractures. Groundwater velocities are increased by these factors, and could result in the creation of plumes of heated water. Plumes of heated water are less likely to occur where the aquifer is thicker and conduits are absent, due to advective heat transport becoming focused between the injection well and the production well in lower permeability situations. These areas also correspond to the areas of decreased transmissivity in several parts of the Upper Carbonate Aquifer, and may not be capable of producing the required volumes of groundwater for thermal applications. Taking into account these permeability features in planning and design of non-consumptive groundwater systems in the Upper Carbonate Aquifer helps to minimize both drawdown and changes in aquifer temperature. 8 refs., 2 figs.

  16. Origin and behaviour of microorganisms and particles in selected karst aquifer systems

    OpenAIRE

    Pronk, Michiel; Zwahlen, François; Goldscheider, Nico

    2009-01-01

    Karst aquifers represent an important groundwater resource world-wide. They are, however, highly vulnerable to contamination due to fast transport and limited contaminant attenuation processes encountered in such systems. Pathogenic microorganisms are among the most frequent and problematic contaminants in groundwater from karst aquifers. It is generally accepted that the presence of faecal indicator bacteria, such as Escherichia coli and enterococci, in groundwater indicates the possible pre...

  17. Conceptual and numerical modeling of the Guaraní Aquifer System

    Directory of Open Access Journals (Sweden)

    L. Rodríguez

    2012-08-01

    Full Text Available In large aquifers relevant for their considerable size, regional groundwater modeling remains challenging given geologic complexity and data scarcity in space and time. The Guaraní Aquifer System is the largest transboundary aquifer in South America. It contains an enormous volume of water, however, it is not well known being difficult to assess the impact of exploitation currently used to supply over 25 million inhabitants. This is a sensitive issue because the aquifer is shared by four countries. Moreover, an integrated groundwater model, and therefore, a global water balance were not available. In this work, a transient regional scale model for the entire aquifer based upon five simplified, equally plausible conceptual models represented by different hydraulic conductivity parametrizations, is used to analyze the flow system and water balance components. Combining an increasing number of hydraulic conductivity zones and an appropriate set of boundary conditions, the hypothesis of a continuous sedimentary unit yielded errors within the calibration target in a regional sense. The magnitude of the water budget terms resulted very similar for all parametrizations. Recharge and stream/aquifer fluxes were the dominant components representing, on average, 84.2% of total inflows and 61.4% of total outflows, respectively. However, leakage was small compared to stream discharges of main rivers. For instance, the simulated average leakage for the Uruguay river was 8 m3 s−1 while the observed absolute minimum discharge was 382 m3 s−1. Streams located in heavily pumped regions switched from a gaining condition on early years to a losing condition over time. Water is discharged through the aquifer boundaries, except at the eastern boundary. On average, pumping represented 16.2% of inflows while aquifer storage experienced a small overall increment. The model water balance indicates that the current rate of

  18. Putative Effect of Aquifer Recharge on the Abundance and Taxonomic Composition of Endemic Microbial Communities

    OpenAIRE

    Renee J Smith; Paterson, James S.; Cally A Sibley; John L Hutson; Mitchell, James G.

    2015-01-01

    Drought events and the overexploitation of freshwater resources have led to the increased need to manage groundwater reserves. Aquifer storage and recovery (ASR), whereby artificial water is injected into aquifers for storage, is one of the proposed methods by which freshwater supplies can be increased. Microbial clogging following injection, however, is a major issue. Here, during laboratory simulations of ASR, we used flow cytometry and bar-coded pyrosequencing to investigate changes in mic...

  19. Predicted nitrate and arsenic concentrations in basin-fill aquifers of the Southwestern United States

    Science.gov (United States)

    Anning, David W.; Paul, Angela P.; McKinney, Tim S.; Huntington, Jena M.; Bexfield, Laura M.; Thiros, Susan A.

    2012-01-01

    The National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey (USGS) is conducting a regional analysis of water quality in the principal aquifer systems across the United States. The Southwest Principal Aquifers (SWPA) study is building a better understanding of the susceptibility and vulnerability of basin-fill aquifers in the region to groundwater contamination by synthesizing baseline knowledge of groundwater-quality conditions in 16 basins previously studied by the NAWQA Program. The improved understanding of aquifer susceptibility and vulnerability to contamination is assisting in the development of tools that water managers can use to assess and protect the quality of groundwater resources. About 46.6 million people live in the SWPA study area, mostly in urban areas, but also in rural, agricultural communities that cultivate about 14.4 million acres of cropland. Other rural areas contain small communities with mining, retirement, or tourism/recreational-based economies. Because of the generally limited availability of surface-water supplies in the arid to semiarid climate, cultural and economic activities in the region are particularly dependent on good-quality groundwater supplies. In the year 2000, about 33.7 million acre-feet (acre-ft) of surface water was diverted from streams, and about 23.0 million acre-ft of groundwater was withdrawn from basin-fill aquifers in the SWPA study area. Irrigation and public-supply withdrawals from basin-fill aquifers in the study area for 2000 were about 18.0 million acre-ft and 4.1 million acre-ft, respectively, and together account for about one quarter of the total withdrawals from all aquifers in the United States. Although irrigation and public supply are the primary uses of basin-fill aquifer withdrawals in the study area, water use varies locally by basin, and withdrawals for industrial, mining, and electric power generation also are substantial in some areas.

  20. Groundwater – meltwater coupling in an active proglacial sandur aquifer in southeast Iceland [Abstract only

    OpenAIRE

    O Dochartaigh, Brighid; MacDonald, Alan; Wilson, Paul; Black, Andrew; Everest, Jez

    2015-01-01

    The sandur proglacial to Virkisjokull, a rapidly retreating glacier in southeast Iceland, forms a thick (at least 50-100m), high permeability, high storage aquifer that is actively coupled with the meltwater river. The sandur aquifer has been characterised by a combination of piezometer drilling, permeability testing and geophysics, and groundwater-meltwater coupling has been investigated by regular monitoring of hydrochemistry, stable isotopes and dissolved gases and by continuous monitoring...

  1. Enumeration and Biomass Estimation of Bacteria in Aquifer Microcosm Studies by Flow Cytometry

    OpenAIRE

    DeLeo, P. C.; Baveye, P

    1996-01-01

    Flow cytometry was used to enumerate and characterize bacteria from a sand column microcosm simulating aquifer conditions. Pure cultures of a species of Bacillus isolated from subsurface sediments or Bacillus megaterium were first evaluated to identify these organisms' characteristic histograms. Counting was then carried out with samples from the aquifer microcosms. Enumeration by flow cytometry was compared with more-traditional acridine orange direct counting. These two techniques gave stat...

  2. The vulnerability of the free aquifers using functions of time of trip

    International Nuclear Information System (INIS)

    The determination of an aquifers vulnerability degree represents a support instrument for hydraulic resources management. It is also important for territory ordering and planning because it guarantors groundwater conservation. Achieving the determination of procedures for vulnerability maps construction, using measurable parameters, integrated as a function, is a practical methodology with very important and vantages over traditional methodologies. It is considered that the pollutant trip time from the surface to the aquifers is a good vulnerability indicator

  3. The impact of boundary conditions on CO2 capacity estimation in aquifers

    OpenAIRE

    Smith, D.J.; Bentham, M.; Holloway, S.; Noy, D.J.; Chadwick, R.A.

    2010-01-01

    The boundary conditions of an aquifer determine the extent to which fluids (including formation water and CO2) and pressure can be transferred into adjacent geological formations, either laterally or vertically. Aquifer boundaries can be faults, lithological boundaries, formation pinch-outs, salt walls, or outcrop. In many cases compliance with regulations preventing CO2 storage influencing areas outside artificial boundaries defined by non-geological criteria (international bound...

  4. Relationships between microbial community structure and hydrochemistry in a landfill leachate-polluted aquifer.

    OpenAIRE

    Roling, W.F.M.; Breukelen, van, R.; Braster, M; Lin, B.; Verseveld, van, Marloes

    2001-01-01

    Knowledge about the relationship between microbial community structure and hydrogeochemistry (e.g., pollution, redox and degradation processes) in landfill leachate-polluted aquifers is required to develop tools for predicting and monitoring natural attenuation. In this study analyses of pollutant and redox chemistry were conducted in parallel with culture-independent profiling of microbial communities present in a well-defined aquifer (Banisveld, The Netherlands). Degradation of organic cont...

  5. Hysteresis, regime shifts, and non-stationarity in aquifer recharge-storage-discharge systems

    Science.gov (United States)

    Klammler, Harald; Jawitz, James; Annable, Michael; Hatfield, Kirk; Rao, Suresh

    2016-04-01

    Based on physical principles and geological information we develop a parsimonious aquifer model for Silver Springs, one of the largest karst springs in Florida. The model structure is linear and time-invariant with recharge, aquifer head (storage) and spring discharge as dynamic variables at the springshed (landscape) scale. Aquifer recharge is the hydrological driver with trends over a range of time scales from seasonal to multi-decadal. The freshwater-saltwater interaction is considered as a dynamic storage mechanism. Model results and observed time series show that aquifer storage causes significant rate-dependent hysteretic behavior between aquifer recharge and discharge. This leads to variable discharge per unit recharge over time scales up to decades, which may be interpreted as a gradual and cyclic regime shift in the aquifer drainage behavior. Based on field observations, we further amend the aquifer model by assuming vegetation growth in the spring run to be inversely proportional to stream velocity and to hinder stream flow. This simple modification introduces non-linearity into the dynamic system, for which we investigate the occurrence of rate-independent hysteresis and of different possible steady states with respective regime shifts between them. Results may contribute towards explaining observed non-stationary behavior potentially due to hydrological regime shifts (e.g., triggered by gradual, long-term changes in recharge or single extreme events) or long-term hysteresis (e.g., caused by aquifer storage). This improved understanding of the springshed hydrologic response dynamics is fundamental for managing the ecological, economic and social aspects at the landscape scale.

  6. The Effects of Subsurface Heterogeneity on Detectability of CO2 Leakage to Shallow Groundwater Aquifers

    Science.gov (United States)

    Wolaver, B. D.; Sun, A. Y.; Nicot, J.; Hovorka, S. D.; Nuñez-Lopez, V.; Young, M.

    2011-12-01

    Numerical simulations of CO2 storage reservoir leakage can be used to assess risks of shallow groundwater aquifer contamination during monitoring network design. Improperly plugged and abandoned wells are well known to represent one of the greatest risks to successful containment at geologic carbon sequestration sites. Casing and cement seal failure of wells penetrating the confining layer may create fast-flow pathways for CO2 and brine migration from the storage reservoir into the shallow subsurface. To protect drinking water aquifers from possible leaks, injection permits require identification of artificial penetrations and evaluation that wells are adequately plugged and abandoned. However, assumptions made during well evaluation may overlook the likelihood of well failure leading to a leak into an aquifer. We present a monitoring approach that provides quick and accurate detection in the event of a leak to an aquifer. Sand and shale facies are classified to simulate aquifer heterogeneity using representative borehole geophysical data from Texas, U.S.A. Gulf Coast Aquifer System wells. Numerical models simulate pressure perturbations in response to a leak to an aquifer overlying a storage reservoir. Candidate monitoring well locations for a possible leak of randomly selected location are chosen from a suite of possible wells based on the detectability of CO2 leakage from the groundwater model. We first show that the locations and magnitudes of leakage can be identified for homogeneous aquifers by using an inversion procedure and pressure observations. We then consider the effects of conceptual model uncertainty, pressure measurement error, and background noise on detectability of leaky wells. While substantial previous work quantified pressure perturbations caused by leaky wells using analytical solutions or simple numerical model configurations, the effects of formation heterogeneity on pressure perturbation and other uncertain factors are not well examined

  7. Seawater intrusion barrier in the deltaic Llobregat aquifer (Barcelona, Spain): performance and pilot phase results

    OpenAIRE

    Ortuño Gobern, Felip; Molinero Huguet, Jorge José; Custodio Gimena, Emilio; Juárez Álvarez, Iker; Garrido, Teresa; Fraile, Josep

    2011-01-01

    The main aquifer of the Llobregat Delta (Barcelona, Spain) is affected by seawater intrusion processes since the 1960s. The Catalan Water Agency is currently promoting several actions of artificial aquifer recharge, including the construction of a positive hydraulic barrier in order to stop the advance of the seawater intrusion. Such a positive hydraulic barrier works by injecting reclaimed water in 14 wells. This is the first time that a project of this type is performed in Spain and i...

  8. HISTORICAL CONTAMINATION OF GROUNDWATER RESOURCES IN THE NORTH COAST KARST AQUIFERS OF PUERTO RICO

    OpenAIRE

    Padilla, Ingrid; Irizarry, Celys; Steele, Katherine

    2011-01-01

    The North Coast Karst Aquifer System of Puerto Rico is the island’s most productive aquifer. The characteristics that make it highly productive also make it vulnerable to contamination. This research, which addresses the historical contamination of groundwater resources in the northern karst region was conducted through integration of spatial hydrogeologic and contaminant concentration data in the La Plata-Arecibo area. The study used GIS technologies and focused on phthalates and chlorinated...

  9. Hydrogeochemical and isotope study of the granular aquifer in the Comarca Lagunera, Mexico

    International Nuclear Information System (INIS)

    The Comarca Lagunera is one of the main agricultural, cattle raising, and mining regions of the country. Their sources of water are the rivers Nazas and Aguanaval (50%) and a quaternary multilayer granular aquifer (50%), which underlies an area of 15,000 km2. The overexploitation of the aquifer and the deterioration of its quality by the presence of arsenic, have carried out adverse effects on the health and economy of the region. There are three hypothesis about the arsenic origin: pesticides lixiviation, mineral wastes, and continental sediments deposited during the aquifer formation. These hypothesis do not explain satisfactorily the occurrence of arsenic and other heavy metals in the aquifer. The objectives of this study are to: a) Determine the origin and evolution of arsenic; b) estimate the vulnerability of regions where groundwater is still of good quality; and C) actualize the hydrogeochemical knowledge of the system. The used methodology is based on: The analysis of the physical framework, the hydrogeochemical actualization of the aquifer and the isotope characterization of the ground water (δ18O, δ2H, 3H γ 14C). The interpretation of results shows that the arsenic origin in the system could be a combining effect of two geologic events: 1) The magmatic process that generated the intrusive and extrusive igneous rocks of the region, originated an hydrothermal system which yielded a great variety of oligoelements; and 2) the sedimentation of alluvial-lacustrine materials bearing arsenic, which were transported by the rivers Nazas and Aguanaval during the aquifer formation. The water table has experimented drawdowns of 10 to 95 during 45 years of development. The groundwater is predominantly sodium - sulfate and calcium - sulfate. Extensive areas of the aquifer are quiet above the Mexican standards of TDS, Ca, Na, Cl, NO3, SO4, B, As, and Li. Furthermore, there are other collateral effects which are increasing the vulnerability of the aquifer and the soil

  10. AQUIFEM-SALT; a finite-element model for aquifers containing a seawater interface

    Science.gov (United States)

    Voss, C.I.

    1984-01-01

    Described are modifications to AQUIFEM, a finite element areal ground-water flow model for aquifer evaluation. The modified model, AQUIFEM-SALT, simulates an aquifer containing a freshwater body that freely floats on seawater. Parts of the freshwater lens may be confined above and below by less permeable units. Theory, code modifications, and model verification are discussed. A modified input data list is included. This report is intended as a companion to the original AQUIFEM documentation. (USGS)

  11. Origin of brackish groundwater in a sandstone aquifer on Bornholm, Denmark

    DEFF Research Database (Denmark)

    Jørgensen, Niels Oluf; Heinemeier, Jan

    2008-01-01

    A multi-isotope approach in combination with hydrochemical data and borehole logging is applied to identify the source of brackish groundwater in a borehole in the well field of Neksø Municipal Waterworks in Bornholm, Denmark. The aquifer lithology consists of fractured Lower Cambrian sandstones...... reflecting long water-rock interaction and suggest a contribution of palaeowater from the fractured crystalline basement which has intruded into the Lower Cambrian sandstone aquifer....

  12. Spatio-temporal analysis of potential aquifer recharge: Application to the Basin of Mexico

    Science.gov (United States)

    Carrera-Hernández, J. J.; Gaskin, S. J.

    2008-05-01

    SummaryRegional estimates of aquifer recharge are needed in data-scarce regions such as the Basin of Mexico, where nearly 20 million people are located and where the Basin's aquifer system represents the main water source. In order to develop the spatio-temporal estimates of aquifer recharge and to analyze to what extent urban growth has affected aquifer recharge, this work presents a daily soil water balance which uses different vegetation and soil types as well as the effect of topography on climatological variables and evapotranspiration. The soil water balance was applied on a daily time step in the Basin of Mexico for the period 1975-1986, obtaining an annually-lumped potential recharge flow of 10.9-23.8 m 3/s (35.9-78.1 mm) in the entire Basin, while the monthly values for the year with the largest lumped recharge value (1981 = 78.1 mm) range from 1 m 3/s (0.3 mm) in December to 87.9 m 3/s (23.7 mm) in June. As aquifer recharge in the Basin mainly occurs by subsurface flow from its enclosing mountains as Mountain Block Recharge, urban growth has had a minimal impact on aquifer recharge, although it has diminished recharge in the alluvial plain.

  13. Analysis of an unconfined aquifer subject to asynchronous dual-tide propagation

    Science.gov (United States)

    Rotzoll, K.; El-Kadi, A. I.; Gingerich, S.B.

    2008-01-01

    Most published solutions for aquifer responses to ocean tides focus on the one-sided attenuation of the signal as it propagates inland. However, island aquifers experience periodic forcing from the entire coast, which can lead to integrated effects of different tidal signals, especially on narrow high-permeability islands. In general, studies disregard a potential time lag as the tidal wave sweeps around the island. We present a one-dimensional analytical solution to the ground water flow equation subject to asynchronous and asymmetric oscillating head conditions on opposite boundaries and test it on data from an unconfined volcanic aquifer in Maui. The solution considers sediment-damping effects at the coastline. The response of Maui Aquifers indicate that water table elevations near the center of the aquifer are influenced by a combination of tides from opposite coasts. A better match between the observed ground water head and the theoretical response can be obtained with the proposed dual-tide solution than with single-sided solutions. Hydraulic diffusivity was estimated to be 2.3 ?? 107 m 2/d. This translates into a hydraulic conductivity of 500 m/d, assuming a specific yield of 0.04 and an aquifer thickness of 1.8 km. A numerical experiment confirmed the hydraulic diffusivity value and showed that the y-intercepts of the modal attenuation and phase differences estimated by regression can approximate damping factors caused by low-permeability units at the boundary.

  14. Pumping from unconfined aquifers of limited saturated thickness with reference to wellpoints and horizontal wells

    Science.gov (United States)

    Rushton, K. R.; Brassington, F. C.

    2016-03-01

    Groundwater in unconfined aquifers of limited saturated thickness can be a valuable resource but frequently it is not developed because conventional boreholes are unsuitable. However, successful exploitation of shallow unconfined aquifers has been achieved using either a line of wellpoints or horizontal wells extending for more than 100 m. The flow processes by which wellpoints and horizontal wells collect water from unconfined aquifers are explored by developing conceptual and computational models. Several representative examples are considered and it is found that similar discharges occur if the wellpoints are closely spaced. The sensitivity of the yield to physical dimensions of the wells and aquifers is explored; the impact of alternative aquifer parameters is also examined. Results from these computational models are used to identify the causes of air entry into wellpoint systems; the prevention of air entry into horizontal wells is also considered. This evaluation demonstrates that wellpoint systems and horizontal wells can efficiently abstract water from unconfined aquifers of limited saturated thickness provided that precautions are taken to prevent air entry.

  15. Snowmelt induced hydrologic perturbations drive dynamic microbiological and geochemical behaviors across a shallow riparian aquifer

    Science.gov (United States)

    Danczak, Robert; Yabusaki, Steven; Williams, Kenneth; Fang, Yilin; Hobson, Chad; Wilkins, Michael

    2016-05-01

    Shallow riparian aquifers represent hotspots of biogeochemical activity in the arid western US. While these environments provide extensive ecosystem services, little is known of how natural environmental perturbations influence subsurface microbial communities and associated biogeochemical processes. Over a six-month period we tracked the annual snowmelt-driven incursion of groundwater into the vadose zone of an aquifer adjacent to the Colorado River, leading to increased dissolved oxygen (DO) concentrations in the normally suboxic saturated zone. Strong biogeochemical heterogeneity was measured across the site, with abiotic reactions between DO and sulfide minerals driving rapid DO consumption and mobilization of redox active species in reduced aquifer regions. Conversely, extensive DO increases were detected in less reduced sediments. 16S rRNA gene surveys tracked microbial community composition within the aquifer, revealing strong correlations between increases in putative oxygen-utilizing chemolithoautotrophs and heterotrophs and rising DO concentrations. The gradual return to suboxic aquifer conditions favored increasing abundances of 16S rRNA sequences matching members of the Microgenomates (OP11) and Parcubacteria (OD1) that have been strongly implicated in fermentative processes. Microbial community stability measurements indicated that deeper aquifer locations were relatively less affected by geochemical perturbations, while communities in shallower locations exhibited the greatest change. Reactive transport modeling of the geochemical and microbiological results supported field observations, suggesting that a predictive framework can be applied to develop a greater understanding of such environments.

  16. 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.

  17. Aquifer Vulnerability Assessment Based on Sequence Stratigraphic and ³⁹Ar Transport Modeling.

    Science.gov (United States)

    Sonnenborg, Torben O; Scharling, Peter B; Hinsby, Klaus; Rasmussen, Erik S; Engesgaard, Peter

    2016-03-01

    A large-scale groundwater flow and transport model is developed for a deep-seated (100 to 300 m below ground surface) sedimentary aquifer system. The model is based on a three-dimensional (3D) hydrostratigraphic model, building on a sequence stratigraphic approach. The flow model is calibrated against observations of hydraulic head and stream discharge while the credibility of the transport model is evaluated against measurements of (39)Ar from deep wells using alternative parameterizations of dispersivity and effective porosity. The directly simulated 3D mean age distributions and vertical fluxes are used to visualize the two-dimensional (2D)/3D age and flux distribution along transects and at the top plane of individual aquifers. The simulation results are used to assess the vulnerability of the aquifer system that generally has been assumed to be protected by thick overlaying clayey units and therefore proposed as future reservoirs for drinking water supply. The results indicate that on a regional scale these deep-seated aquifers are not as protected from modern surface water contamination as expected because significant leakage to the deeper aquifers occurs. The complex distribution of local and intermediate groundwater flow systems controlled by the distribution of the river network as well as the topographical variation (Tóth 1963) provides the possibility for modern water to be found in even the deepest aquifers.

  18. Impacts of Soil-aquifer Heat and Water Fluxes on Simulated Global Climate

    Science.gov (United States)

    Krakauer, N.Y.; Puma, Michael J.; Cook, B. I.

    2013-01-01

    Climate models have traditionally only represented heat and water fluxes within relatively shallow soil layers, but there is increasing interest in the possible role of heat and water exchanges with the deeper subsurface. Here, we integrate an idealized 50m deep aquifer into the land surface module of the GISS ModelE general circulation model to test the influence of aquifer-soil moisture and heat exchanges on climate variables. We evaluate the impact on the modeled climate of aquifer-soil heat and water fluxes separately, as well as in combination. The addition of the aquifer to ModelE has limited impact on annual-mean climate, with little change in global mean land temperature, precipitation, or evaporation. The seasonal amplitude of deep soil temperature is strongly damped by the soil-aquifer heat flux. This not only improves the model representation of permafrost area but propagates to the surface, resulting in an increase in the seasonal amplitude of surface air temperature of >1K in the Arctic. The soil-aquifer water and heat fluxes both slightly decrease interannual variability in soil moisture and in landsurface temperature, and decrease the soil moisture memory of the land surface on seasonal to annual timescales. The results of this experiment suggest that deepening the modeled land surface, compared to modeling only a shallower soil column with a no-flux bottom boundary condition, has limited impact on mean climate but does affect seasonality and interannual persistence.

  19. Structural and hydrogeological features of a Lias carbonate aquifer in the Triffa Plain, NE Morocco

    Science.gov (United States)

    Sardinha, J.; Carneiro, J. F.; Zarhloule, Y.; Barkaoui, A.; Correia, A.; Boughriba, M.; Rimi, A.; El Houadi, B.

    2012-09-01

    The rising demand for water and the contamination of shallow water table aquifers has led authorities in NE Morocco to look for deeper groundwater resources in the Triffa Plain, namely in Lower Jurassic (Lias) dolomitic limestones. The liassic aquifer is of strategic importance for the development of the region, however, its hydrodynamic behaviour is poorly understood due to lack of hydrogeological data and block structure. This article presents a first effort towards understanding the structure and hydraulic behaviour of the aquifer. Exploration borehole data and results from geophysical campaigns were integrated into a GIS environment to build a preliminary model of the aquifer structure. The aquifer behaves as an unconfined aquifer in the northern part of the Béni Snassen Mountains (the recharge area), but as it dips to the north, it becomes confined by marls and shales of the Middle/Upper Jurassic. Even though piezometric level data are scarce, a tentative piezometric map was produced. Three blocks separated by NW-SE trending faults in a horst and graben structure, with distinct flow behaviours were identified: Berkane, Fezouane and Sidi Rahmoun blocks. Those blocks also show differences in hydraulic conductivity distribution. As a result of the reaction with the dolomitic limestones, the groundwater is of calcium-magnesium bicarbonate type. Groundwater temperature as measured in springs ranges from 29 °C to 37 °C in springs and constitutes a potential low enthalpy geothermal resource.

  20. Radionuclide transport in the Neogene aquifer system located in the environment of the Boom clay

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. In the framework the Belgian research program on the long term management of high-level and/or long-lived radioactive waste coordinated by ONDRAF/NIRAS, the Boom Clay is considered as a reference host rock for the geological disposal of high-level radioactive waste in NE-Belgium (Campine area). In the frame of the performance assessments of a disposal system located in the Boom Clay Formation, the transport of radionuclides diffusing through the clay barrier into the aquifers located above is modelled. The transport model for the Neogene aquifer is based on a series of groundwater flow models simulating the aquifer systems in the surroundings of the Boom Clay. This series of groundwater models include the regional north-eastern Belgium model simulating flow both above and below the Boom Clay, the recently updated deep-aquifer pumping model, simulating transient flow in the over-exploited aquifers below the Boom Clay and finally the catchment-scale Neogene aquifer model, simulating flow in the aquifer system above the Boom Clay. The Neogene aquifer system consists of two main aquifers. The Pliocene aquifer is located at the top, separated from the underlying Miocene aquifer by the Kasterlee Clay aquitard. The Miocene aquifer consists of three hydrostratigraphic units: the Diest, Berchem and Voort Formations; with the last two having a lower hydraulic conductivity than the Diest unit. The transport model for the Neogene aquifer represents a fraction of the catchment-scale Neogene aquifer model. It stretches from the local divide between the Grote and Kleine Nete Rivers up to the Kleine Nete River, representing the main model sink. The boundary conditions and the sources/sinks in the Pliocene aquifer are defined mostly by the surface water features, such as the rivers, brooks, lakes and canals. In the partially confined Miocene aquifer, the effect of the surface water features is dampened and the heads at the model