Inorganic carbon cycle in soil-rock-groundwater system in karst and fissured aquifers

Directory of Open Access Journals (Sweden)

Ajda Koceli

2013-12-01

Full Text Available The paper presents a systematic analysis of the isotopic composition of carbon (δ13CCaCO3 in carbonate rocks in central Slovenia, representing karst and fissured aquifers, and share of carbon contributions from carbonate dissolution and degradation of organic matter in aquifers, calculated from the mass balance equation. 59 samples of rocks (mainly dolomites from Upper Permian to Upper Triassic age were analyzed. Samples of carbonate rocks were pulverized and ground to fraction of 45 μm and for determination of δ13CCaCO3 analyzed with mass spectrometer for analyses of stable isotopes of light elements-IRMS. The same method was used for determination of isotopic composition of dissolved inorganic carbon (δ13CDIC in groundwater for 54 of 59 locations. Values of δ13CCaCO3 are in the range from -2.0 ‰ to +4.1 ‰, with an average δ13CCaCO3 value of +2.2 ‰. These values are typical for marine carbonates with δ13CCaCO3 around 0 ‰, although δ13CCaCO3 values differ between groups depending on the origin and age. Early diagenetic dolomites have relatively higher values of δ13CCaCO3 compared to other analyzed samples. The lowest values of δ13CCaCO3 were observed in Cordevolian and Bača dolomite, probably due to late diagenesis, during which meteoric water with lower isotopic carbon composition circulated in the process of sedimentation. Values of δ13CDIC range from -14.6 ‰ to -8.2 ‰. Higher δ13CDIC values (-8.2 ‰ indicate a low proportion of soil CO2 in the aquifer and rapid infiltration, while lower values (-14.6 ‰ indicate higher proportion of soil CO2 in the aquifer and slower infiltration. Calculated contributions of carbon from organic matter / dissolution of carbonates in the karstic and fissured aquifers s how a similar proportion (50 % : 50 %.

Fresh Water Generation from Aquifer-Pressured Carbon Storage: Annual Report FY09

Energy Technology Data Exchange (ETDEWEB)

Wolery, T; Aines, R; Hao, Y; Bourcier, W; Wolfe, T; Haussman, C

2009-11-25

This project is establishing the potential for using brine pressurized by Carbon Capture and Storage (CCS) operations in saline formations as the feedstock for desalination and water treatment technologies including reverse osmosis (RO) and nanofiltration (NF). The aquifer pressure resulting from the energy required to inject the carbon dioxide provides all or part of the inlet pressure for the desalination system. Residual brine is reinjected into the formation at net volume reduction, such that the volume of fresh water extracted balances the volume of CO{sub 2} injected into the formation. This process provides additional CO{sub 2} storage capacity in the aquifer, reduces operational risks (cap-rock fracturing, contamination of neighboring fresh water aquifers, and seismicity) by relieving overpressure in the formation, and provides a source of low-cost fresh water to offset costs or operational water needs. This multi-faceted project combines elements of geochemistry, reservoir engineering, and water treatment engineering. The range of saline formation waters is being identified and analyzed. Computer modeling and laboratory-scale experimentation are being used to examine mineral scaling and osmotic pressure limitations. Computer modeling is being used to evaluate processes in the storage aquifer, including the evolution of the pressure field. Water treatment costs are being evaluated by comparing the necessary process facilities to those in common use for seawater RO. There are presently limited brine composition data available for actual CCS sites by the site operators including in the U.S. the seven regional Carbon Sequestration Partnerships (CSPs). To work around this, we are building a 'catalog' of compositions representative of 'produced' waters (waters produced in the course of seeking or producing oil and gas), to which we are adding data from actual CCS sites as they become available. Produced waters comprise the most common

Hydrogeological impact of fault zones on a fractured carbonate aquifer, Semmering (Austria)

Science.gov (United States)

Mayaud, Cyril; Winkler, Gerfried; Reichl, Peter

2015-04-01

Fault zones are the result of tectonic processes and are geometrical features frequently encountered in carbonate aquifer systems. They can hamper the fluid migration (hydrogeological barriers), propagate the movement of fluid (draining conduits) or be a combination of both processes. Numerical modelling of fractured carbonate aquifer systems is strongly bound on the knowledge of a profound conceptual model including geological and tectonic settings such as fault zones. In further consequence, numerical models can be used to evaluate the conceptual model and its introduced approximations. The study was conducted in a fractured carbonate aquifer built up by permomesozoic dolo/limestones of the Semmering-Wechsel complex in the Eastern Alps (Austria). The aquifer has an assumed thickness of about 200 m and dips to the north. It is covered by a thin quartzite layer and a very low permeable layer of quartz-phyllite having a thickness of up to several hundred meters. The carbonate layer crops out only in the southern part of the investigation area, where it receives autogenic recharge. The geological complexity affects some uncertainties related to the extent of the model area, which was determined to be about 15 km². Three vertical fault zones cross the area approximately in a N-S direction. The test site includes an infrastructural pilot tunnel gallery of 4.3 km length with two pumping stations, respectively active since August 1997 and June 1998. The total pumping rate is about 90 l/s and the drawdown data were analysed analytically, providing a hydraulic conductivity of about 5E-05 m/s for the carbonate layer. About 120 m drawdown between the initial situation and situation with pumping is reported by piezometers. This led to the drying up of one spring located at the southern border of the carbonates. A continuum approach using MODFLOW-2005 was applied to reproduce numerically the observed aquifer behaviour and investigate the impact of the three fault zones. First

Near-surface, marine seismic-reflection data defines potential hydrogeologic confinement bypass in a tertiary carbonate aquifer, southeastern Florida

Science.gov (United States)

Cunningham, Kevin J.; Walker, Cameron; Westcott, Richard L.

2012-01-01

Approximately 210 km of near-surface, high-frequency, marine seismic-reflection data were acquired on the southeastern part of the Florida Platform between 2007 and 2011. Many high-resolution, seismic-reflection profiles, interpretable to a depth of about 730 m, were collected on the shallow-marine shelf of southeastern Florida in water as shallow as 1 m. Landward of the present-day shelf-margin slope, these data image middle Eocene to Pleistocene strata and Paleocene to Pleistocene strata on the Miami Terrace. This high-resolution data set provides an opportunity to evaluate geologic structures that cut across confining units of the Paleocene to Oligocene-age carbonate rocks that form the Floridan aquifer system.Seismic profiles image two structural systems, tectonic faults and karst collapse structures, which breach confining beds in the Floridan aquifer system. Both structural systems may serve as pathways for vertical groundwater flow across relatively low-permeability carbonate strata that separate zones of regionally extensive high-permeability rocks in the Floridan aquifer system. The tectonic faults occur as normal and reverse faults, and collapse-related faults have normal throw. The most common fault occurrence delineated on the reflection profiles is associated with karst collapse structures. These high-frequency seismic data are providing high quality structural analogs to unprecedented depths on the southeastern Florida Platform. The analogs can be used for assessment of confinement of other carbonate aquifers and the sealing potential of deeper carbonate rocks associated with reservoirs around the world.

Simulation of flow in the Edwards Aquifer, San Antonio region, Texas, and refinement of storage and flow concepts

Science.gov (United States)

Maclay, Robert W.; Land, Larry F.

1988-01-01

The Edwards aquifer is a complexly faulted, carbonate aquifer lying within the Balcones fault zone of south-central Texas. The aquifer consists of thin- to massive-bedded limestone and dolomite, most of which is in the form of mudstones and wackestones. Well-developed secondary porosity has formed in association with former erosional surfaces within the carbonate rocks, within dolomitized-burrowed tidal and evaporitic deposits, and along inclined fractures to produce an aquifer with transmissivities greater than 100 ft2/s. The aquifer is recharged mainly by streamflow losses in the outcrop area of the Edwards aquifer and is discharged by major springs located at considerable distances, as much as 150 mi, from the areas of recharge and by wells. Ground-water flow within the Edwards aquifer of the San Antonio region was simulated to investigate concepts relating to the storage and flow characteristics. The concepts of major interest were the effects of barrier faults on flow direction, water levels, springflow, and storage within the aquifer. A general-purpose, finite-difference model, modified to provide the capability of representing barrier faults, was used to simulate ground-water flow and storage in the aquifer. The approach in model development was to conduct a series of simulations beginning with a simple representation of the aquifer framework and then proceeding to subsequent representations of increasing complexity. The simulations investigated the effects of complex geologic structures and of significant changes in transmissivity, anisotropy, and storage coefficient. Initial values of transmissivity, anisotropy, and storage coefficient were estimated based on concepts developed in previous studies. Results of the simulations confirmed the original estimates of transmissivity values (greater than 100 square feet/s) in the confined zone of the aquifer between San Antonio and Comal Springs. A storage coefficient of 0.05 in the unconfined zone of the aquifer

Geostatistical Borehole Image-Based Mapping of Karst-Carbonate Aquifer Pores.

Science.gov (United States)

Sukop, Michael C; Cunningham, Kevin J

2016-03-01

Quantification of the character and spatial distribution of porosity in carbonate aquifers is important as input into computer models used in the calculation of intrinsic permeability and for next-generation, high-resolution groundwater flow simulations. Digital, optical, borehole-wall image data from three closely spaced boreholes in the karst-carbonate Biscayne aquifer in southeastern Florida are used in geostatistical experiments to assess the capabilities of various methods to create realistic two-dimensional models of vuggy megaporosity and matrix-porosity distribution in the limestone that composes the aquifer. When the borehole image data alone were used as the model training image, multiple-point geostatistics failed to detect the known spatial autocorrelation of vuggy megaporosity and matrix porosity among the three boreholes, which were only 10 m apart. Variogram analysis and subsequent Gaussian simulation produced results that showed a realistic conceptualization of horizontal continuity of strata dominated by vuggy megaporosity and matrix porosity among the three boreholes. © 2015, National Ground Water Association.

Potentially bioavailable natural organic carbon and hydrolyzable amino acids in aquifer sediments

Science.gov (United States)

Thomas, Lashun K.; Widdowson, Mark A.; Novak, John T.; Chapelle, Francis H.; Benner, Ronald; Kaiser, Karl

2012-01-01

This study evaluated the relationship between concentrations of operationally defined potentially bioavailable organic -carbon (PBOC) and hydrolyzable amino acids (HAAs) in sediments collected from a diverse range of chloroethene--contaminated sites. Concentrations of PBOC and HAA were measured using aquifer sediment samples collected at six selected study sites. Average concentrations of total HAA and PBOC ranged from 1.96 ± 1.53 to 20.1 ± 25.6 mg/kg and 4.72 ± 0.72 to 443 ± 65.4 mg/kg, respectively. Results demonstrated a statistically significant positive relationship between concentrations of PBOC and total HAA present in the aquifer sediment (p amino acids are known to be readily biodegradable carbon compounds, this relationship suggests that the sequential chemical extraction procedure used to measure PBOC is a useful indicator of bioavailable carbon in aquifer sediments. This, in turn, is consistent with the interpretation that PBOC measurements can be used for estimating the amount of natural organic carbon available for driving the reductive dechlorination of chloroethenes in groundwater systems.

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

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

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

Geochemical detection of carbon dioxide in dilute aquifers.

Science.gov (United States)

Carroll, Susan; Hao, Yue; Aines, Roger

2009-03-26

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 10(3) to 2 x 10(6) 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. 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 >or= 10(4) 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 in the lower most permeable unit and does

Microbial diversity and impact on carbonate geochemistry across a changing geochemical gradient in a karst aquifer.

Science.gov (United States)

Gray, Cassie J; Engel, Annette S

2013-02-01

Although microbes are known to influence karst (carbonate) aquifer ecosystem-level processes, comparatively little information is available regarding the diversity of microbial activities that could influence water quality and geological modification. To assess microbial diversity in the context of aquifer geochemistry, we coupled 16S rRNA Sanger sequencing and 454 tag pyrosequencing to in situ microcosm experiments from wells that cross the transition from fresh to saline and sulfidic water in the Edwards Aquifer of central Texas, one of the largest karst aquifers in the United States. The distribution of microbial groups across the transition zone correlated with dissolved oxygen and sulfide concentration, and significant variations in community composition were explained by local carbonate geochemistry, specifically calcium concentration and alkalinity. The waters were supersaturated with respect to prevalent aquifer minerals, calcite and dolomite, but in situ microcosm experiments containing these minerals revealed significant mass loss from dissolution when colonized by microbes. Despite differences in cell density on the experimental surfaces, carbonate loss was greater from freshwater wells than saline, sulfidic wells. However, as cell density increased, which was correlated to and controlled by local geochemistry, dissolution rates decreased. Surface colonization by metabolically active cells promotes dissolution by creating local disequilibria between bulk aquifer fluids and mineral surfaces, but this also controls rates of karst aquifer modification. These results expand our understanding of microbial diversity in karst aquifers and emphasize the importance of evaluating active microbial processes that could affect carbonate weathering in the subsurface.

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

Science.gov (United States)

1981-06-01

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 unglaciated central region, glaciated Appalachians, unglaciated Appalachians, coastal plain, Hawaii, and Alaska are discussed.

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.

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

Science.gov (United States)

1981-06-01

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 western mountains, alluvial basins, Columbia LAVA plateau, Colorado plateau, high plains, and glaciated central region are discussed.

Regional potentiometric-surface map of the Great Basin carbonate and alluvial aquifer system in Snake Valley and surrounding areas, Juab, Millard, and Beaver Counties, Utah, and White Pine and Lincoln Counties, Nevada

Science.gov (United States)

Gardner, Philip M.; Masbruch, Melissa D.; Plume, Russell W.; Buto, Susan G.

2011-01-01

Water-level measurements from 190 wells were used to develop a potentiometric-surface map of the east-central portion of the regional Great Basin carbonate and alluvial aquifer system in and around Snake Valley, eastern Nevada and western Utah. The map area covers approximately 9,000 square miles in Juab, Millard, and Beaver Counties, Utah, and White Pine and Lincoln Counties, Nevada. Recent (2007-2010) drilling by the Utah Geological Survey and U.S. Geological Survey has provided new data for areas where water-level measurements were previously unavailable. New water-level data were used to refine mapping of the pathways of intrabasin and interbasin groundwater flow. At 20 of these locations, nested observation wells provide vertical hydraulic gradient data and information related to the degree of connection between basin-fill aquifers and consolidated-rock aquifers. Multiple-year water-level hydrographs are also presented for 32 wells to illustrate the aquifer system's response to interannual climate variations and well withdrawals.

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.

Arsenic mobilization in an alluvial aquifer of the Terai region, Nepal

Directory of Open Access Journals (Sweden)

Jasmine Diwakar

2015-09-01

New Hydrological Insights for the Region: The aquifer is characterized by Ca-HCO3 type water and is multi-contaminated, with the WHO guideline values exceeded for As, Mn and F in 80%, 70% and 40% of cases respectively. The middle portion of the floodplain was heavily contaminated with As, predominantly as As(III. The river water displayed some evidence of reductive processes in the hyporheic zone contributing As, Fe and Mn to baseflow and also had elevated fluoride. The generally sub-oxic conditions, dominance of As(III and Fe2+ species and positive correlation between As and both NH3 and UV-absorbance at 254 nm suggests that oxidation of organic matter coupled with microbial mediated reductive processes are important for mobilizing As in the aquifer. The apparent decoupling between As(III(aq and Fe2+(aq may be explained by precipitation of siderite, but further work is required to resolve this unambiguously. Along with reductive processes, other geochemical mechanisms including silicate weathering and precipitation/dissolution of carbonate minerals, control the solute and major ion composition of groundwater.

Ground-water quality in the carbonate-rock aquifer of the Great Basin, Nevada and Utah, 2003

Science.gov (United States)

Schaefer, Donald H.; Thiros, Susan A.; Rosen, Michael R.

2005-01-01

The carbonate-rock aquifer of the Great Basin is named for the thick sequence of Paleozoic limestone and dolomite with lesser amounts of shale, sandstone, and quartzite. It lies primarily in the eastern half of the Great Basin and includes areas of eastern Nevada and western Utah as well as the Death Valley area of California and small parts of Arizona and Idaho. The carbonate-rock aquifer is contained within the Basin and Range Principal Aquifer, one of 16 principal aquifers selected for study by the U.S. Geological Survey’s National Water- Quality Assessment Program.Water samples from 30 ground-water sites (20 in Nevada and 10 in Utah) were collected in the summer of 2003 and analyzed for major anions and cations, nutrients, trace elements, dissolved organic carbon, volatile organic compounds (VOCs), pesticides, radon, and microbiology. Water samples from selected sites also were analyzed for the isotopes oxygen-18, deuterium, and tritium to determine recharge sources and the occurrence of water recharged since the early 1950s.Primary drinking-water standards were exceeded for several inorganic constituents in 30 water samples from the carbonate-rock aquifer. The maximum contaminant level was exceeded for concentrations of dissolved antimony (6 μg/L) in one sample, arsenic (10 μg/L) in eleven samples, and thallium (2 μg/L) in one sample. Secondary drinking-water regulations were exceeded for several inorganic constituents in water samples: chloride (250 mg/L) in five samples, fluoride (2 mg/L) in two samples, iron (0.3 mg/L) in four samples, manganese (0.05 mg/L) in one sample, sulfate (250 mg/L) in three samples, and total dissolved solids (500 mg/L) in seven samples.Six different pesticides or metabolites were detected at very low concentrations in the 30 water samples. The lack of VOC detections in water sampled from most of the sites is evidence thatVOCs are not common in the carbonate-rock aquifer. Arsenic values for water range from 0.7 to 45.7 �

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.

Assessing groundwater availability in a folded carbonate aquifer through the development of a numerical model

Science.gov (United States)

Di Salvo, Cristina; Romano, Emanuele; Guyennon, Nicolas; Bruna Petrangeli, Anna; Preziosi, Elisabetta

2015-04-01

The study of aquifer systems from a quantitative point of view is fundamental for adopting water management plans aiming at preserving water resources and reducing environmental risks related to groundwater level and discharge changes. This is also what the European Union Water Framework Directive (WFD, 2000/60/EC) states, holding the development of numerical models as a key aspect for groundwater management. The objective of this research is to i) define a methodology for modeling a complex hydrogeological structure in a structurally folded carbonate area and ii) estimate the concurrent effects of exploitation and climate changes on groundwater availability through the implementation of a 3D groundwater flow model. This study concerns the Monte Coscerno karst aquifer located in the Apennine chain in Central Italy in the Nera River Valley.This aquifer, is planned to be exploited in the near future for water supply. Negative trends of precipitation in Central Italy have been reported in relation to global climate changes, which are expected to affect the availability of recharge to carbonate aquifers throughout the region . A great concern is the combined impact of climate change and groundwater exploitation, hence scenarios are needed taking into account the effect of possible temperature and precipitation trends on recharge rates. Following a previous experience with model conceptualization and long-term simulation of groundwater flow, an integrated three-dimensional groundwater model has been developed for the Monte Coscerno aquifer. In a previous paper (Preziosi et al 2014) the spatial distribution of recharge to this aquifer was estimated through the Thornthwaite Mather model at a daily time step using as inputs past precipitation and temperature values (1951-2013) as well as soil and landscape properties. In this paper the numerical model development is described. On the basis of well logs from private consulting companies and literature cross sections the

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.

Fluid Dynamics of Carbon Dioxide Disposal into Saline Aquifers

Energy Technology Data Exchange (ETDEWEB)

Garcia, Julio Enrique [Univ. of California, Berkeley, CA (United States)

2003-01-01

Injection of carbon dioxide (CO₂) into saline aquifers has been proposed as a means to reduce greenhouse gas emissions (geological carbon sequestration). Large-scale injection of CO₂ 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 CO₂ and NaCl has been conducted. As a result, accurate representations and models for predicting the overall thermophysical behavior of the system CO₂-H₂O-NaCl are proposed and incorporated into the numerical simulator TOUGH2/ECO2. The basic problem of CO₂ 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 CO₂ injection project at the Sleipner Vest Field in the Norwegian sector of the North Sea and the evaluation of fluid flow dynamics effects of CO₂ 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 CO₂. 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 CO₂ 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 CO₂) the viscosity of carbon

EPA Region 1 Sole Source Aquifers

Science.gov (United States)

This coverage contains boundaries of EPA-approved sole source aquifers. Sole source aquifers are defined as an aquifer designated as the sole or principal source of drinking water for a given aquifer service area; that is, an aquifer which is needed to supply 50% or more of the drinking water for the area and for which there are no reasonable alternative sources should the aquifer become contaminated.The aquifers were defined by a EPA hydrogeologist. Aquifer boundaries were then drafted by EPA onto 1:24000 USGS quadrangles. For the coastal sole source aquifers the shoreline as it appeared on the quadrangle was used as a boundary. Delineated boundaries were then digitized into ARC/INFO.

Interlaboratory study of a method for determining nonvolatile organic carbon in aquifer materials

Science.gov (United States)

Caughey, M.E.; Barcelona, M.J.; Powell, R.M.; Cahill, R.A.; Gron, C.; Lawrenz, D.; Meschi, P.L.

1995-01-01

The organic carbon fraction in aquifer materials exerts a major influence on the subsurface mobilities of organic and organic-associated contaminants. The spatial distribution of total organic carbon (TOC) in aquifer materials must be determined before the transport of hydrophobic organic pollutants in aquifers can be modeled accurately. Previous interlaboratory studies showed that it is difficult to measure TOC concentrations 1%. We have tested a new analytical method designed to improve the accuracy and precision of nonvolatile TOC quantitation in geologic materials that also contain carbonate minerals. Four authentic aquifer materials and one NIST standard reference material were selected as test materials for a blind collaborative study. Nonvolatile TOC in these materials ranged from 0.05 to 1.4%, while TIC ranged from 0.46 to 12.6%. Sample replicates were digested with sulfurous acid, dried at 40??C, and then combusted at 950??C using LECO or UIC instruments. For the three test materials that contained >2% TIC, incomplete acidification resulted in a systematic positive bias of TOC values reported by five of the six laboratories that used the test method. Participants did not have enough time to become proficient with the new method before they analyzed the test materials. A seventh laboratory successfully used an alternative method that analyzed separate liquid and solid fractions of the acidified sample residues. ?? 1995 Springer-Verlag.

Regional Variation of CH4 and N2 Production Processes in the Deep Aquifers of an Accretionary Prism.

Science.gov (United States)

Matsushita, Makoto; Ishikawa, Shugo; Nagai, Kazushige; Hirata, Yuichiro; Ozawa, Kunio; Mitsunobu, Satoshi; Kimura, Hiroyuki

2016-09-29

Accretionary prisms are mainly composed of ancient marine sediment scraped from the subducting oceanic plate at a convergent plate boundary. Large amounts of anaerobic groundwater and natural gas, mainly methane (CH4) and nitrogen gas (N2), are present in the deep aquifers associated with an accretionary prism; however, the origins of these gases are poorly understood. We herein revealed regional variations in CH4 and N2 production processes in deep aquifers in the accretionary prism in Southwest Japan, known as the Shimanto Belt. Stable carbon isotopic and microbiological analyses suggested that CH4 is produced through the non-biological thermal decomposition of organic matter in the deep aquifers in the coastal area near the convergent plate boundary, whereas a syntrophic consortium of hydrogen (H2)-producing fermentative bacteria and H2-utilizing methanogens contributes to the significant production of CH4 observed in deep aquifers in midland and mountainous areas associated with the accretionary prism. Our results also demonstrated that N2 production through the anaerobic oxidation of organic matter by denitrifying bacteria is particularly prevalent in deep aquifers in mountainous areas in which groundwater is affected by rainfall.

Modeling carbon dioxide sequestration in saline aquifers: Significance of elevated pressures and salinities

International Nuclear Information System (INIS)

Allen, D.E.; Strazisar, B.R.; Soong, Y.; Hedges, S.W.

2005-01-01

The ultimate capacity of saline formations to sequester carbon dioxide by solubility and mineral trapping must be determined by simulating sequestration with geochemical models. These models, however, are only as reliable as the data and reaction scheme on which they are based. Several models have been used to make estimates of carbon dioxide solubility and mineral formation as a function of pressure and fluid composition. Intercomparison of modeling results indicates that failure to adjust all equilibrium constants to account for elevated carbon dioxide pressures results in significant errors in both solubility and mineral formation estimates. Absence of experimental data at high carbon dioxide pressures and high salinities make verification of model results difficult. Results indicate standalone solubility models that do not take mineral reactions into account will underestimate the total capacity of aquifers to sequester carbon dioxide in the long term through enhanced solubility and mineral trapping mechanisms. Overall, it is difficult to confidently predict the ultimate sequestration capacity of deep saline aquifers using geochemical models. (author)

Understanding the carbon cycle in a Late Quaternary-age limestone aquifer system using radiocarbon of dissolved inorganic and organic carbon

Science.gov (United States)

Bryan, Eliza; Meredith, Karina T.; Baker, Andy; Andersen, Martin S.; Post, Vincent E. A.

2017-04-01

Estimating groundwater residence time is critical for our understanding of hydrogeological systems, for groundwater resource assessments and for the sustainable management of groundwater resources. Due to its capacity to date groundwater up to 30 thousand years old, as well as the ubiquitous nature of dissolved carbon (as organic and inorganic forms) in groundwater, 14C is the most widely used radiogenic dating technique in regional aquifers. However, the geochemistry of carbon in groundwater systems includes interaction with the atmosphere, biosphere and geosphere, which results in multiple sources and sinks of carbon that vary in time and space. Identifying these sources of carbon and processes relating to its release or removal is important for understanding the evolution of the groundwater and essential for residence time calculations. This study investigates both the inorganic and organic facets of the carbon cycle in groundwaters throughout a freshwater lens and mixing zone of a carbonate island aquifer and identifies the sources of carbon that contribute to the groundwater system. Groundwater samples were collected from shallow (5-20 m) groundwater wells on a small carbonate Island in Western Australia in September 2014 and analysed for major and minor ions, stable water isotopes (SWIs: δ18O, δ2H), 3H, 14C and 13C carbon isotope values of both DIC and DOC, and 3H. The composition of groundwater DOC was investigated by Liquid Chromatography-Organic Carbon Detection (LC-OCD) analysis. The presence of 3H (0.12 to 1.35 TU) in most samples indicates that groundwaters on the Island are modern, however the measured 14CDIC values (8.4 to 97.2 pmc) suggest that most samples are significantly older due to carbonate dissolution and recrystallisation reactions that are identified and quantified in this work. 14CDOC values (46.6 to 105.6 pMC) were higher than 14CDIC values and were well correlated with 3H values, however deeper groundwaters had lower 14CDOC values than

Megaporosity and permeability of Thalassinoides-dominated ichnofabrics in the Cretaceous karst-carbonate Edwards-Trinity aquifer system, Texas

Science.gov (United States)

Cunningham, Kevin J.; Sukop, Michael C.

2012-01-01

Current research has demonstrated that trace fossils and their related ichnofabrics can have a critical impact on the fluid-flow properties of hydrocarbon reservoirs and groundwater aquifers. Most petroleum-associated research has used ichnofabrics to support the definition of depositional environments and reservoir quality, and has concentrated on siliciclastic reservoir characterization and, to a lesser degree, carbonate reservoir characterization (for example, Gerard and Bromley, 2008; Knaust, 2009). The use of ichnology in aquifer characterization has almost entirely been overlooked by the hydrologic community because the dynamic reservoir-characterization approach has not caught on with hydrologists and so hydrology is lagging behind reservoir engineering in this area (de Marsily and others, 2005). The objective of this research is to show that (1) ichnofabric analysis can offer a productive methodology for purposes of carbonate aquifer characterization, and (2) a clear relation can exist between ichnofabrics and groundwater flow in carbonate aquifers.

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.

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

International Nuclear Information System (INIS)

Wood, W.W.; Low, W.H.

1987-01-01

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

Fate of the herbicide glufosinate-ammonium in the sandy, low-organic-carbon aquifer at CFB Borden, Ontario, Canada

Science.gov (United States)

Allen-King, Richelle M.; Butler, Barbara J.; Reichert, Barbara

1995-04-01

The herbicide glufosinate-ammonium was persistent in aerobic sandy aquifer material in laboratory batch and field in situ microcosms when added at concentrations of 50-400 μg L -1. In contrast, the compound is biotransformed relatively quickly in surface soil. Glufosinate transformation and metabolite (3-methylphosphinyl-propionic acid) production in carbonamended laboratory microcosms demonstrated that the aquifer system was carbon-limited with respect to glufosinate transformation. Microbiological test showed that flufosinateammonium and sodium-glufosinate was be used as a nitrogen source, in the presence of sufficient carbon. Glufosinate was not used by the native microorganisms as a source of phosphorus, nor metabolized as a sole carbon and energy source. Ammonium appeared to be preferred over glufosinate as a nitrogen source. When representative microbial strains isolated from the Borden aquifer were tested, most were glufosinate-ammonium tolerant. Complete inhibition of some isolates was demonstrated only at very high concentrations of 2-4 g L -1. The research suggests that in an aquifer with a relatively low clay content and little labile organic carbon, such as the sandy aquifer at the field site, glufosinate will be persistent and transport will be essentially unretarded. The availability of alternative nitrogen sources was also indicated as a parameter that can affect persistence.

EPA Region 1 Sole Source Aquifers

Data.gov (United States)

U.S. Environmental Protection Agency — This coverage contains boundaries of EPA-approved sole source aquifers. Sole source aquifers are defined as an aquifer designated as the sole or principal source of...

Regional modelling of the confined aquifers below the Boom clay in NE-Belgium

International Nuclear Information System (INIS)

Vandersteen, K.; Gedeon, M.; Marivoet, J.; Wouters, L.

2012-01-01

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

Field Investigation and Modeling Development for Hydrological and Carbon Cycles in Southwest Karst Region of China

Science.gov (United States)

Hu, X. B.

2017-12-01

It is required to understanding water cycle and carbon cycle processes for water resource management and pollution prevention and global warming influence in southwest karst region of China. Lijiang river basin is selected as our study region. Interdisciplinary field and laboratory experiments with various technologies are conducted to characterize the karst aquifers in detail. Key processes in the karst water cycle and carbon cycle are determined. Based on the MODFLOW-CFP model, new watershed flow and carbon cycle models are developed coupled subsurface and surface water flow models. Our study focus on the karst springshed in Mao village, the mechanisms coupling carbon cycle and water cycle are explored. This study provides basic theory and simulation method for water resource management and groundwater pollution prevention in China karst region.

Engineered in situ bioremediation of a petroleum hydrocarbon-contaminated aquifer: assessment of mineralization based on alkalinity, inorganic carbon and stable carbon isotope balances

Science.gov (United States)

Hunkeler, Daniel; Höhener, Patrick; Bernasconi, Stefano; Zeyer, Josef

1999-04-01

A concept is proposed to assess in situ petroleum hydrocarbon mineralization by combining data on oxidant consumption, production of reduced species, CH 4, alkalinity and dissolved inorganic carbon (DIC) with measurements of stable isotope ratios. The concept was applied to a diesel fuel contaminated aquifer in Menziken, Switzerland, which was treated by engineered in situ bioremediation. In the contaminated aquifer, added oxidants (O 2 and NO 3-) were consumed, elevated concentrations of Fe(II), Mn(II), CH 4, alkalinity and DIC were detected and the DIC was generally depleted in 13C compared to the background. The DIC production was larger than expected based on the consumption of dissolved oxidants and the production of reduced species. Stable carbon isotope balances revealed that the DIC production in the aquifer originated mainly from microbial petroleum hydrocarbon mineralization, and that geochemical reactions such as carbonate dissolution produced little DIC. This suggests that petroleum hydrocarbon mineralization can be underestimated if it is determined based on concentrations of dissolved oxidants and reduced species.

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).

Hydrochemical Regions of the Glacial Aquifer System, Northern United States, and Their Environmental and Water-Quality Characteristics

Science.gov (United States)

Arnold, Terri L.; Warner, Kelly L.; Groschen, George E.; Caldwell, James P.; Kalkhoff, Stephen J.

2008-01-01

The glacial aquifer system in the United States is a large (953,000 square miles) regional aquifer system of heterogeneous composition. As described in this report, the glacial aquifer system includes all unconsolidated geologic material above bedrock that lies on or north of the line of maximum glacial advance within the United States. Examining ground-water quality on a regional scale indicates that variations in the concentrations of major and minor ions and some trace elements most likely are the result of natural variations in the geologic and physical environment. Study of the glacial aquifer system was designed around a regional framework based on the assumption that two primary characteristics of the aquifer system can affect water quality: intrinsic susceptibility (hydraulic properties) and vulnerability (geochemical properties). The hydrochemical regions described in this report were developed to identify and explain regional spatial variations in ground-water quality in the glacial aquifer system within the hypothetical framework context. Data analyzed for this study were collected from 1991 to 2003 at 1,716 wells open to the glacial aquifer system. Cluster analysis was used to group wells with similar ground-water concentrations of calcium, chloride, fluoride, magnesium, potassium, sodium, sulfate, and bicarbonate into five unique groups. Maximum Likelihood Classification was used to make the extrapolation from clustered groups of wells, defined by points, to areas of similar water quality (hydrochemical regions) defined in a geospatial model. Spatial data that represented average annual precipitation, average annual temperature, land use, land-surface slope, vertical soil permeability, average soil clay content, texture of surficial deposits, type of surficial deposit, and potential for ground-water recharge were used in the Maximum Likelihood Classification to classify the areas so the characteristics of the hydrochemical regions would resemble the

Managed aquifer recharge through off-season irrigation in agricultural regions

Science.gov (United States)

Niswonger, Richard G.; Morway, Eric D.; Triana, Enrique; Huntington, Justin L.

2017-08-01

Options for increasing reservoir storage in developed regions are limited and prohibitively expensive. Projected increases in demand call for new long-term water storage to help sustain agriculture, municipalities, industry, and ecological services. Managed aquifer recharge (MAR) is becoming an integral component of water resources around the world. However, MAR faces challenges, including infrastructure costs, difficulty in enhancing recharge, water quality issues, and lack of available water supplies. Here we examine, through simulation modeling of a hypothetical agricultural subbasin in the western U.S., the potential of agricultural managed aquifer recharge (Ag-MAR) via canal seepage and off-season field irrigation. Weather phenomenon in many regions around the world exhibit decadal and other multiyear cycles of extreme precipitation. An ongoing challenge is to develop approaches to store greater amounts of water during these events. Simulations presented herein incorporate Ag-MAR programs and demonstrate that there is potential to enhance regional recharge by 7-13%, increase crop consumptive use by 9-12%, and increase natural vegetation consumption by 20-30%, where larger relative increases occur for lower aquifer hydraulic conductivity and higher specific yield values. Annual increases in groundwater levels were 7 m, and sustained levels following several years of drought were greater than 2 m. Results demonstrate that Ag-MAR has great potential to enhance long-term sustainability of water resources in agricultural basins.

Managed aquifer recharge through off-season irrigation in agricultural regions

Science.gov (United States)

Niswonger, Richard; Morway, Eric D.; Triana, Enrique; Huntington, Justin L.

2017-01-01

Options for increasing reservoir storage in developed regions are limited and prohibitively expensive. Projected increases in demand call for new long-term water storage to help sustain agriculture, municipalities, industry, and ecological services. Managed aquifer recharge (MAR) is becoming an integral component of water resources around the world. However, MAR faces challenges, including infrastructure costs, difficulty in enhancing recharge, water quality issues, and lack of available water supplies. Here we examine, through simulation modeling of a hypothetical agricultural subbasin in the western U.S., the potential of agricultural managed aquifer recharge (Ag-MAR) via canal seepage and off-season field irrigation. Weather phenomenon in many regions around the world exhibit decadal and other multiyear cycles of extreme precipitation. An ongoing challenge is to develop approaches to store greater amounts of water during these events. Simulations presented herein incorporate Ag-MAR programs and demonstrate that there is potential to enhance regional recharge by 7–13%, increase crop consumptive use by 9–12%, and increase natural vegetation consumption by 20–30%, where larger relative increases occur for lower aquifer hydraulic conductivity and higher specific yield values. Annual increases in groundwater levels were 7 m, and sustained levels following several years of drought were greater than 2 m. Results demonstrate that Ag-MAR has great potential to enhance long-term sustainability of water resources in agricultural basins.

Heterogeneous carbonaceous matter in sedimentary rock lithocomponents causes significant trichloroethylene (TCE) sorption in a low organic carbon content aquifer/aquitard system.

Science.gov (United States)

Choung, Sungwook; Zimmerman, Lisa R; Allen-King, Richelle M; Ligouis, Bertrand; Feenstra, Stanley

2014-10-15

This study evaluated the effects of heterogeneous thermally altered carbonaceous matter (CM) on trichloroethylene (TCE) sorption for a low fraction organic carbon content (foc) alluvial sedimentary aquifer and aquitard system (foc=0.046-0.105%). The equilibrium TCE sorption isotherms were highly nonlinear with Freundlich exponents of 0.46-0.58. Kerogen+black carbon was the dominant CM fraction extracted from the sediments and accounted for >60% and 99% of the total in the sands and silt, respectively. Organic petrological examination determined that the kerogen included abundant amorphous organic matter (bituminite), likely of marine origin. The dark calcareous siltstone exhibited the greatest TCE sorption among aquifer lithocomponents and accounted for most sorption in the aquifer. The results suggest that the source of the thermally altered CM, which causes nonlinear sorption, was derived from parent Paleozoic marine carbonate rocks that outcrop throughout much of New York State. A synthetic aquifer-aquitard unit system (10% aquitard) was used to illustrate the effect of the observed nonlinear sorption on mass storage potential at equilibrium. The calculation showed that >80% of TCE mass contained in the aquifer was sorbed on the aquifer sediment at aqueous concentration TCE groundwater plume in the aquifer studied. It is implied that sorption may similarly contribute to TCE persistence in other glacial alluvial aquifers with similar geologic characteristics, i.e., comprised of sedimentary rock lithocomponents that contain thermally altered CM. Copyright © 2014 Elsevier B.V. All rights reserved.

Using Novel Laboratory Incubations and Field Experiments to Identify the Source and Fate of Reactive Organic Carbon in an Arsenic-contaminated Aquifer System

Science.gov (United States)

Stahl, M.; Tarek, M. H.; Badruzzaman, B.; Harvey, C. F.

2017-12-01

Characterizing the sources and fate of organic matter (OM) within aquifer systems is key to our understanding of both the broader global carbon cycle as well as the quality of our groundwater resources. The linkage between the subsurface carbon cycle and groundwater quality is perhaps nowhere more apparent than in the aquifer systems of South and Southeast Asia, where the contamination of groundwater with geogenic arsenic (As) is widespread and threatens the health of millions of individuals. OM fuels the biogeochemical processes driving As mobilization within these aquifers, however the source (i.e., modern surface-derived or aged sedimentary OM) of the reactive OM is widely debated. To characterize the sources of OM driving aquifer redox processes we tracked DIC and DOC concentrations and isotopes (stable and radiocarbon) along groundwater flow-paths and beneath an instrumented study pond at a field site in Bangladesh. We also conducted a set of novel groundwater incubation experiments, where we carbon-dated the DOC at the start and end of a experiment in order to determine the age of the OM that was mineralized. Our carbon/isotope balance reveals that aquifer recharge introduces a large quantity of young (i.e. near modern) OM that is efficiently mineralized within the upper few meters of the aquifer, effectively limiting this pool of reactive surface-sourced OM from being transported deeper into the aquifer where significant As mobilization takes place. The OM mineralized past the upper few meters is an aged, sedimentary source. Consistent with our field data, our incubation experiments show that past the upper few meters of the aquifer the reactive DOC is significantly older than the bulk DOC and has an age consistent with sedimentary OM. Combining our novel set of incubation experiments and a carbon/isotope balance along groundwater flow-paths and beneath our study pond we have identified the sources of reactive OM across different aquifer depths in a

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).

Organic and inorganic carbon dynamics in a karst aquifer: Santa Fe River Sink-Rise system, north Florida, USA

Science.gov (United States)

Jin, Jin; Zimmerman, Andrew R.; Moore, Paul J.; Martin, Jonathan B.

2014-03-01

Spatiotemporal variations in dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), major ions concentrations and other geochemical parameters including stable carbon isotopes of DIC (δ13CDIC), were measured in surface water and deep and shallow well water samples of the Santa Fe River Sink-Rise eogenetic karst system, north Florida, USA. Three end-member water sources were identified: one DOC-rich/DIC-poor/δ13CDIC-depleted, one DOC-poor/DIC-rich/δ13CDIC-enriched, and one enriched in major ions. Given their spatiotemporal distributions, they were presumed to represent soil water, upper aquifer groundwater, and deep aquifer water sources, respectively. Using assumed ratios of Na+, Cl, and SO42- for each end-member, a mixing model calculated the contribution of each water source to each sample. Then, chemical effects of biogeochemical reactions were calculated as the difference between those predicted by the mixing model and measured species concentrations. In general, carbonate mineral dissolution occurred throughout the Sink-Rise system, surface waters were net autotrophic and the subsurface was in metabolic balance, i.e., no net DOC or DIC production or consumption. However, there was evidence for chemolithoautotrophy, perhaps by hydrogen oxidizing microbes, at some deep aquifer sites. Mineralization of this autochthonous natural dissolved organic matter (NDOM) led to localized carbonate dissolution as did surface water-derived NDOM supplied to shallow well sites during the highest flow periods. This study demonstrates linkages between hydrology, abiotic and microbial processes and carbon dynamics and has important implications for groundwater quality, karst morphologic evolution, and hydrogeologic projects such as aquifer storage and recovery in karst systems.

Elucidating the Role of Carbon Sources on Abiotic and Biotic Release of Arsenic into Cambodian Aquifers

Science.gov (United States)

Koeneke, M.

2017-12-01

Arsenic (As) is a naturally occurring contaminant in Cambodia that has been contaminating well-water sources of millions of people. Commonly, studies look into the biotic factors that cause the arsenic to be released from aquifer sediments to groundwater. However, abiotic release of As from sediments, though little studied, may also play key roles in As contamination of well water. The goal of this research is to quantitatively compare organic-carbon mediated abiotic and biotic release of arsenic from sediments to groundwater. Batch anaerobic incubation experiments under abiotic (sodium azide used to immobilize microbes) and biotic conditions were conducted using Cambodian aquifer sediments, four different organic carbon sources (sodium lactate, sodium citrate, sodium oxalate, and humic acid), and six different carbon concentrations (0, 1, 2.5, 5, 10, 25mg C/L). Dissolved arsenic, iron(Fe), and manganese(Mn) concentrations in the treatments were measured 112 days . In addition, sediment and solution carbon solution was measured . Collectively, these show how different carbon sources, different carbon concentrations, and how abiotic and biotic factors impact the release of arsenic from Cambodian sediments into aquifers. Overall, an introduction of organic carbon to the soil increases the amount of As released from the sediment. The biotic + abiotic and abiotic conditions seemed to play a minimal role in the amount of As released. Dissolved species analysis showed us that 100% of the As was As(V), Our ICP-MS results vary due to the heterogeneity of samples, but when high levels are Fe are seen in solution, we also see high levels of As. We also see higher As concentrations when there is a smaller amount of Mn in solution.

Molecular characterization of organic matter mobilized from Bangladeshi aquifer sediment: tracking carbon compositional change during microbial utilization

Directory of Open Access Journals (Sweden)

L. E. Pracht

2018-03-01

Full Text Available Bioavailable organic carbon in aquifer recharge waters and sediments can fuel microbial reactions with implications for groundwater quality. A previous incubation experiment showed that sedimentary organic carbon (SOC mobilized off sandy sediment collected from an arsenic-contaminated and methanogenic aquifer in Bangladesh was bioavailable; it was transformed into methane. We used high-resolution mass spectrometry to molecularly characterize this mobilized SOC, reference its composition against dissolved organic carbon (DOC in surface recharge water, track compositional changes during incubation, and advance understanding of microbial processing of organic carbon in anaerobic environments. Organic carbon mobilized off aquifer sediment was more diverse, proportionately larger, more aromatic, and more oxidized than DOC in surface recharge. Mobilized SOC was predominately composed of terrestrially derived organic matter and had characteristics signifying that it evaded microbial processing within the aquifer. Approximately 50 % of identified compounds in mobilized SOC and in DOC from surface recharge water contained sulfur. During incubation, after mobilized SOC was converted into methane, new organosulfur compounds with high S-to-C ratios and a high nominal oxidation state of carbon (NOSC were detected. We reason that these detected compounds formed abiotically following microbial reduction of sulfate to sulfide, which could have occurred during incubation but was not directly measured or that they were microbially synthesized. Most notably, microbes transformed all carbon types during incubation, including those currently considered thermodynamically unviable for microbes to degrade in anaerobic conditions (i.e., those with a low NOSC. In anaerobic environments, energy yields from redox reactions are small and the amount of energy required to remove electrons from highly reduced carbon substrates during oxidation decreases the thermodynamic

Molecular characterization of organic matter mobilized from Bangladeshi aquifer sediment: tracking carbon compositional change during microbial utilization

Science.gov (United States)

Pracht, Lara E.; Tfaily, Malak M.; Ardissono, Robert J.; Neumann, Rebecca B.

2018-03-01

Bioavailable organic carbon in aquifer recharge waters and sediments can fuel microbial reactions with implications for groundwater quality. A previous incubation experiment showed that sedimentary organic carbon (SOC) mobilized off sandy sediment collected from an arsenic-contaminated and methanogenic aquifer in Bangladesh was bioavailable; it was transformed into methane. We used high-resolution mass spectrometry to molecularly characterize this mobilized SOC, reference its composition against dissolved organic carbon (DOC) in surface recharge water, track compositional changes during incubation, and advance understanding of microbial processing of organic carbon in anaerobic environments. Organic carbon mobilized off aquifer sediment was more diverse, proportionately larger, more aromatic, and more oxidized than DOC in surface recharge. Mobilized SOC was predominately composed of terrestrially derived organic matter and had characteristics signifying that it evaded microbial processing within the aquifer. Approximately 50 % of identified compounds in mobilized SOC and in DOC from surface recharge water contained sulfur. During incubation, after mobilized SOC was converted into methane, new organosulfur compounds with high S-to-C ratios and a high nominal oxidation state of carbon (NOSC) were detected. We reason that these detected compounds formed abiotically following microbial reduction of sulfate to sulfide, which could have occurred during incubation but was not directly measured or that they were microbially synthesized. Most notably, microbes transformed all carbon types during incubation, including those currently considered thermodynamically unviable for microbes to degrade in anaerobic conditions (i.e., those with a low NOSC). In anaerobic environments, energy yields from redox reactions are small and the amount of energy required to remove electrons from highly reduced carbon substrates during oxidation decreases the thermodynamic favorability of

A Study of the Connection Among Basin-Fill Aquifers, Carbonate-Rock Aquifers, and Surface-Water Resources in Southern Snake Valley, Nevada

Science.gov (United States)

,

2008-01-01

The Secretary of the Interior through the Southern Nevada Public Lands Management Act approved funding for research to improve understanding of hydrologic systems that sustain numerous water-dependent ecosystems on Federal lands in Snake Valley, Nevada. Some of the streams and spring-discharge areas in and adjacent to Great Basin National Park have been identified as susceptible to ground-water withdrawals (Elliott and others, 2006) and research has shown a high potential for ground-water flow from southern Spring Valley into southern Snake Valley through carbonate rocks that outcrop along a low topographic divide known as the Limestone Hills (Welch and others, 2007). Comprehensive geologic, hydrologic, and chemical information will be collected and analyzed to assess the hydraulic connection between basin-fill aquifers and surface-water resources, water-dependent ecological features, and the regional carbonate-rock aquifer, the known source of many high-discharge springs. Understanding these connections is important because proposed projects to pump and export ground water from Spring and Snake Valleys in Nevada may result in unintended capture of water currently supplying springs, streams, wetlands, limestone caves, and other biologically sensitive areas (fig. 1). The methods that will be used in this study may be transferable to other areas in the Great Basin. The National Park Service, Bureau of Land Management, U.S. Fish and Wildlife Service, and U.S. Forest Service submitted the proposal for funding this research to facilitate science-based land management. Scientists from the U.S. Geological Survey (USGS) Water Resources and Geologic Disciplines, and the University of Nevada, Reno, will accomplish four research elements through comprehensive data collection and analysis that are concentrated in two distinct areas on the eastern and southern flanks of the Snake Range (fig. 2). The projected time line for this research is from July 2008 through September 2011.

Microbial and geochemical investigations of dissolved organic carbon and microbial ecology of native waters from the Biscayne and Upper Floridan Aquifers

Science.gov (United States)

Lisle, John T.; Harvey, Ron W.; Aiken, George R.; Metge, David W.

2010-01-01

Groundwater resources in the United States are under ever-increasing demands for potable, irrigation, and recreational uses. Additionally, aquifer systems are being used or targeted for use as storage areas for treated surface waters and (or) groundwaters via injection (for example, aquifer storage and recovery). To date, the influence that the nutrients, including carbon, in the injected water have on native microbial communities and the biogeochemistry in the subsurface zones used for storage of the injectate has not been determined. In this report, we describe a series of experiments that establishes a baseline dataset for the quantity and quality of organic and inorganic carbon and nutrients in the Biscayne Aquifer (BA) and Upper Floridan Aquifer (UFA) in south Florida. The most significant differences between the BA (26 meters below surface) and UFA (366 meters below surface) are the average specific conductance (0.552 and 6.12 microsiemens per centimeter, respectively), dissolved oxygen (1.6 and 0 milligrams per liter, respectively), and oxidation-reduction potential (40.3 and -358 millivolts, respectively). The dissolved organic carbon from the BA is characterized by carbon originating from terrestrial sources and microbial activities, while the UFA has a distinctive microbial signature. Acetate and lactate are the dominant carbon constituents in both aquifers. Additionally, components of the dissolved organic carbon from the UFA have a total trihalomethane-formation potential that is approximately threefold greater than the maximum contaminat level of 80 micrograms per liter established by the U.S. Environmental Protection Agency. The average native bacterial abundances in the aquifers are similar with 4.69x10^4 cells per milliliter in the BA and 1.33x10^4 cells per milliliter in the UFA. The average bacteriophage abundances are also similar with 1.15x10^5 virus-like particles in the BA and 1.92x10^5 virus-like particles in the UFA. Interestingly, ciliated

Data-base system for northern Midwest regional aquifer-system analysis

Science.gov (United States)

Kontis, A.L.; Mandle, Richard J.

1980-01-01

The U.S. Geological Survey is conducting a study of the Cambrian and Ordovician aquifer system of the northern Midwest as part of a national series of Regional Aquifer-Systems Analysis (RASA). An integral part of this study will be a simulation of the ground-water flow regime using the Geological Survey's three-dimensional finite-difference model. The first step in the modeling effort is the design and development of a systematic set of processes to facilitate the collection, evaluation, manipulation, and use of large quantities of information. A computerized data-base system to accomplish these goals has been completed for the northern Midwest RASA.

Carbon dioxide (CO2) sequestration in deep saline aquifers and formations: Chapter 3

Science.gov (United States)

Rosenbauer, Robert J.; Thomas, Burt

2010-01-01

Carbon dioxide (CO2) capture and sequestration in geologic media is one among many emerging strategies to reduce atmospheric emissions of anthropogenic CO2. This chapter looks at the potential of deep saline aquifers – based on their capacity and close proximity to large point sources of CO2 – as repositories for the geologic sequestration of CO2. The petrochemical characteristics which impact on the suitability of saline aquifers for CO2 sequestration and the role of coupled geochemical transport models and numerical tools in evaluating site feasibility are also examined. The full-scale commercial CO2 sequestration project at Sleipner is described together with ongoing pilot and demonstration projects.

Quantifying the energy required for groundwater pumping across a regional aquifer system

Science.gov (United States)

Ronayne, M. J.; Shugert, D. T.

2017-12-01

Groundwater pumping can be a substantial source of energy expenditure, particularly in semiarid regions with large depths to water. In this study we assessed the energy required for groundwater pumping in the Denver Basin aquifer system, a group of sedimentary rock aquifers used for municipal water supply in Colorado. In recent decades, declining water levels in the Denver Basin aquifers has resulted in increased pumping lifts and higher energy use rates. We quantified the spatially variable energy intensity for groundwater pumping by analyzing spatial variations in the lift requirement. The median energy intensities for two major aquifers were 1.2 and 1.8 kWh m-3. Considering typical municipal well production rates and household water use in the study area, these results indicate that the energy cost associated with groundwater pumping can be a significant fraction (>20%) of the total electricity consumption for all household end uses. Pumping at this scale (hundreds of municipal wells producing from deep aquifers) also generates substantial greenhouse gas emissions. Analytical wellfield modeling conducted as part of this study clearly demonstrates how multiple components of the lift impact the energy requirement. Results provide guidance for water management strategies that reduce energy expenditure.

Water-level altitudes 2015 and water-level changes in the Chicot, Evangeline, and Jasper aquifers and compaction 1973-2014 in the Chicot and Evangeline aquifers, Houston-Galveston region, Texas

Science.gov (United States)

Kasmarek, Mark C.; Ramage, Jason K.; Houston, Natalie A.; Johnson, Michaela R.; Schmidt, Tiffany S.

2015-01-01

Most of the land-surface subsidence in the Houston-Galveston region, Texas, has occurred as a direct result of groundwater withdrawals for municipal supply, commercial and industrial use, and irrigation that depressured and dewatered the Chicot and Evangeline aquifers, thereby causing compaction of the aquifer sediments, mostly in the fine-grained silt and clay layers. This report, prepared by the U.S. Geological Survey 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, is one in an annual series of reports depicting water-level altitudes and water-level changes in the Chicot, Evangeline, and Jasper aquifers and measured cumulative compaction of subsurface sediments in the Chicot and Evangeline aquifers in the Houston-Galveston region. The report contains regional-scale maps depicting approximate 2015 water-level altitudes (represented by measurements made during December 2014–March 2015) for the Chicot, Evangeline, and Jasper aquifers; maps depicting 1-year (2014–15) water-level changes for each aquifer; maps depicting approximate contoured 5-year (2010–15) water-level changes for each aquifer; maps depicting approximate contoured long-term (1990–2015 and 1977–2015) water-level changes for the Chicot and Evangeline aquifers; a map depicting approximate contoured long-term (2000–15) water-level changes for the Jasper aquifer; a map depicting locations of borehole-extensometer sites; and graphs depicting measured cumulative compaction of subsurface sediments at the borehole extensometers during 1973–2014. Three tables listing the water-level data used to construct each water-level map for each aquifer and a table listing the measured cumulative compaction data for each extensometer site and graphs are included.

Exploration of buried carbonate aquifers by the inverse and forward modelling of the Controlled Source Audio-Magnetotelluric data

Science.gov (United States)

Šumanovac, Franjo; Orešković, Jasna

2018-06-01

On the selected cases, Gotalovec in the area of Pannonian basin and Baška in the Dinaridic karst area, that are representing a common hydrogeological model in both regions of Croatia, CSAMT data together with data of other geophysical methods (electrical resistivity tomography, electrical sounding and seismic reflection) enabled the definition of a reliable prognostic geological model. The model consists of carbonate aquifer which underlies an impermeable thick package of clastic deposits. There are great variations of the dolomitic aquifer depths in the Gotalovec area due to strong tectonic activity, while in the Baška area depth changes are caused by the layer folding. The CSAMT method provides the most complete data on lithological and structural relationships in cases of hydrogeological targets deeper than 100 m. Based on the presented models we can conclude that the CSAMT method can provide greater exploration depth than electrical resistivity tomography (ERT) and can be considered as a fundamental geophysical method for exploration of buried carbonate aquifers, deeper than 100 m. But, the CSAMT research may demonstrate its advantages only in the case of very dense layout of CSAMT stations (25-50 m), due to the greater sensitivity to noise in relation to resistivity methods. Interpretation of CSAMT data is more complex in relation to resistivity methods, and a forward modelling method sometimes gives better results than an inversion due to possibility of the use of additional data acquired by other geophysical methods (ERT, electrical sounding and seismic reflection). At greater depths, the resolution of all electrical methods including the CSAMT method is significantly reduced, and seismic reflection can be very useful to resolve deeper lithological interfaces.

Use of static Quantitative Microbial Risk Assessment to determine pathogen risks in an unconfined carbonate aquifer used for Managed Aquifer Recharge.

Science.gov (United States)

Toze, Simon; Bekele, Elise; Page, Declan; Sidhu, Jatinder; Shackleton, Mark

2010-02-01

Managed Aquifer Recharge (MAR) is becoming a mechanism used for recycling treated wastewater and captured urban stormwater and is being used as a treatment barrier to remove contaminants such as pathogens from the recharged water. There is still a need, however, to demonstrate the effectiveness of MAR to reduce any residual risk of pathogens in the recovered water. A MAR research site recharging secondary treated wastewater in an unconfined carbonate aquifer was used in conjunction with a static Quantitative Microbial Risk Assessment (QMRA) to assess the microbial pathogen risk in the recovered water following infiltration and aquifer passage. The research involved undertaking a detailed hydrogeological assessment of the aquifer at the MAR site and determining the decay rates of reference pathogens from an in-situ decay study. These variables along with literature data were then used in the static QMRA which demonstrated that the recovered water at this site did not meet the Australian Guidelines for recycled water when used for differing private green space irrigation scenarios. The results also confirmed the importance of obtaining local hydrogeological data as local heterogeneity can influence of residence time in the aquifer which, in turn, influences the outcomes. The research demonstrated that a static QMRA can be used to determine the residual risk from pathogens in recovered water and showed that it can be a valuable tool in the preliminary design and operation of MAR systems and the incorporation of complementary engineered treatment processes to ensure that there is acceptable health risk from the recovered water. Crown Copyright 2009. Published by Elsevier Ltd. All rights reserved.

Changes in the Regional Groundwater Aquifer and Potential Impacts on Surface Waters in Central Zealand, Denmark

DEFF Research Database (Denmark)

Thorn, Paul

The regional, confined aquifer on the island of Zealand, in eastern Denmark, is the primary aquifer used for large-scale abstraction for the supplies of all larger cities, including Roskilde and the greater Copenhagen metropolitan area. Large-scale groundwater abstraction from this aquifer...... in the area near Lejre Denmark (approximately 15km to the SW of Roskilde) began in 1937, exporting approximately 18 million m3 of water per year to supply the city of Copenhagen. After abstraction began, streams in the area were observed to go dry after extended periods without precipitation, where......, wetlands and lakes in the area. The results show that there was a significant impact on the regional groundwater aquifer in the Langvad river catchment, with groundwater as much as 17m lower in 1987 from 1936 (pre-abstraction). However, in the Elverdam river catchment, the levels remained virtually...

Insights from the salinity origins and interconnections of aquifers in a regional scale sedimentary aquifer system (Adour-Garonne district, SW France): Contributions of δ34S and δ18O from dissolved sulfates and the 87Sr/86Sr ratio

International Nuclear Information System (INIS)

Brenot, Agnès; Négrel, Philippe; Petelet-Giraud, Emmanuelle; Millot, Romain; Malcuit, Eline

2015-01-01

Highlights: • Regional sedimentary aquifer on the Aquitaine Basin (SW France). • Dealing with limited number of groundwater wells available. • Strong control of evaporite dissolution on groundwater dissolved elements. • Guidelines for decision-makers to manage water resources. - Abstract: The multi-layered Eocene aquifer is a regional scale sedimentary aquifer system occupying ∼120,000 km 2 within the Adour-Garonne district (France). Local authorities have recently identified the aquifer as being at risk from extensive irrigation abstractions, threatening the sustainability of this key resource. Because large water abstractions for human activities can significantly influence the natural functioning of such aquifer systems, e.g., with leakage between aquifer layers, which can lead to water quality degradation, the characterization of such large systems constitutes a key point to protect and prevent further deterioration of aquatic ecosystems. This study provides further insight on this large aquifer through a geochemical approach, which addresses the limited number of groundwater wells where sampling is possible. For that purpose, a geochemical analysis combining two isotope systems (δ 34 S SO4 , δ 18 O SO4 and 87 Sr/ 86 Sr) has been applied. The Eocene sedimentary aquifer system (detrital to carbonate deposits) is made up of four aquifer layers, Eocene Infra-Molassic sand, Early Eocene, Middle Eocene and Late Eocene, and has a mineralized area north of the Aquitaine Basin, where groundwater shows strong mineralization and anomalous levels of critical substances (SO 4 , F, etc.), increasing the difficulty of resource exploitation. The extreme heterogeneity of the geochemical composition of the groundwater between the aquifers and within a single aquifer is discussed in terms of the lithological control induced by the lateral variation of facies and interconnections between aquifer layers. Geochemical tools, especially the δ 34 S and δ 18 O from

Simulating flow in karst aquifers at laboratory and sub-regional scales using MODFLOW-CFP

Science.gov (United States)

Gallegos, Josue Jacob; Hu, Bill X.; Davis, Hal

2013-12-01

Groundwater flow in a well-developed karst aquifer dominantly occurs through bedding planes, fractures, conduits, and caves created by and/or enlarged by dissolution. Conventional groundwater modeling methods assume that groundwater flow is described by Darcian principles where primary porosity (i.e. matrix porosity) and laminar flow are dominant. However, in well-developed karst aquifers, the assumption of Darcian flow can be questionable. While Darcian flow generally occurs in the matrix portion of the karst aquifer, flow through conduits can be non-laminar where the relation between specific discharge and hydraulic gradient is non-linear. MODFLOW-CFP is a relatively new modeling program that accounts for non-laminar and laminar flow in pipes, like karst caves, within an aquifer. In this study, results from MODFLOW-CFP are compared to those from MODFLOW-2000/2005, a numerical code based on Darcy's law, to evaluate the accuracy that CFP can achieve when modeling flows in karst aquifers at laboratory and sub-regional (Woodville Karst Plain, Florida, USA) scales. In comparison with laboratory experiments, simulation results by MODFLOW-CFP are more accurate than MODFLOW 2005. At the sub-regional scale, MODFLOW-CFP was more accurate than MODFLOW-2000 for simulating field measurements of peak flow at one spring and total discharges at two springs for an observed storm event.

The relationship of uranium isotopes to oxidation/reduction in the Edwards carbonate aquifer of Texas

International Nuclear Information System (INIS)

Cowart, J.B.

1980-01-01

The concentration of dissolved uranium and 234 U/ 238 U alpha activity ratio ( A.R. ) were determined in water samples from 23 locations in the Edwards carbonate aquifer of south central Texas by isotope dilution methods and alpha spectrometry. (orig./ME)

Intrinsic vulnerability assessment of Sette Comuni Plateau aquifer (Veneto Region, Italy).

Science.gov (United States)

Cucchi, Franco; Franceschini, Giuliana; Zini, Luca; Aurighi, Marina

2008-09-01

Maps illustrating the different degrees of vulnerability within a given area are integral to environmental protection and management policies. The assessment of the intrinsic vulnerability of karst areas is difficult since the type and stage of karst development and the related underground discharge behavior are difficult to determine and quantify. Geographic Information Systems techniques are applied to the evaluation of the vulnerability of an aquifer in the alpine karst area of the Sette Comuni Plateau, in the Veneto Region of northern Italy. The water resources of the studied aquifer are of particular importance to the local communities. This aquifer must therefore be protected from both inappropriate use as well as possible pollution. The SINTACS and SINTACS P(RO) K(ARST) vulnerability assessment methods have been utilized here to create the vulnerability map. SINTACS P(RO) K(ARST) is an adaptation of the parametric managerial model (SINTACS) to karst hydrostructures. The vulnerability map reveals vast zones (81% of the analyzed areas) with a high degree of vulnerability. The presence of well-developed karst structures in these highly vulnerable areas facilitate water percolation, thereby enhancing the groundwater vulnerability risk. Only 1.5 of the studied aquifer have extremely high-vulnerability levels, however these areas include all of the major springs utilized for human consumption. This vulnerability map of the Sette Comuni Plateau aquifer is an indispensable tool for both the effective management of water resources and as support to environmental planning in the Sette Comuni Plateau area.

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.

Water-level altitudes 2013 and water-level changes in the Chicot, Evangeline, and Jasper aquifers and compaction 1973--2012 in the Chicot and Evangeline aquifers, Houston-Galveston region, Texas

Science.gov (United States)

Kasmarek, Mark C.; Johnson, Michaela R.; Ramage, Jason K.

2013-01-01

Most of the subsidence in the Houston-Galveston region, Texas, has occurred as a direct result of groundwater withdrawals for municipal supply, commercial and industrial use, and irrigation that depressured and dewatered the Chicot and Evangeline aquifers, thereby causing compaction mostly in the clay and silt layers of the aquifer sediments. This report, prepared by the U.S. Geological Survey 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, is one in an annual series of reports depicting water-level altitudes and water-level changes in the Chicot, Evangeline, and Jasper aquifers and measured compaction of subsurface sediments in the Chicot and Evangeline aquifers in the Houston-Galveston region. The report contains maps depicting approximate water-level altitudes for 2013 (represented by measurements made during December 2012-February 2013) for the Chicot, Evangeline, and Jasper aquifers; maps depicting 1-year (2012-13) water-level changes for each aquifer; maps depicting 5-year (2008--13) water-level changes for each aquifer; maps depicting long-term (1990-2013 and 1977-2013) water-level changes for the Chicot and Evangeline aquifers; a map depicting long-term (2000-13) water-level changes for the Jasper aquifer; a map depicting locations of borehole-extensometer sites; and graphs depicting measured compaction of subsurface sediments at the extensometers during 1973-2012. Tables listing the data used to construct each water-level map for each aquifer and the compaction graphs are included.

Simulation of groundwater flow in the Edwards-Trinity and related aquifers in the Pecos County region, Texas

Science.gov (United States)

Clark, Brian R.; Bumgarner, Johnathan R.; Houston, Natalie A.; Foster, Adam L.

2014-01-01

The Edwards-Trinity aquifer is a vital groundwater resource for agricultural, industrial, and public supply uses in the Pecos County region of western Texas. The U.S. Geological Survey completed a comprehensive, integrated analysis of available hydrogeologic data to develop a numerical groundwater-flow model of the Edwards-Trinity and related aquifers in the study area in parts of Brewster, Jeff Davis, Pecos, and Reeves Counties. The active model area covers about 3,400 square miles of the Pecos County region of Texas west of the Pecos River, and its boundaries were defined to include the saturated areas of the Edwards-Trinity aquifer. The model is a five-layer representation of the Pecos Valley, Edwards-Trinity, Dockum, and Rustler aquifers. The Pecos Valley aquifer is referred to as the alluvial layer, and the Edwards-Trinity aquifer is divided into layers representing the Edwards part of the Edwards-Trinity aquifer and the Trinity part of the Edwards-Trinity aquifer, respectively. The calibration period of the simulation extends from 1940 to 2010. Simulated hydraulic heads generally were in good agreement with observed values; 1,684 out of 2,860 (59 percent) of the simulated values were within 25 feet of the observed value. The average root mean square error value of hydraulic head for the Edwards-Trinity aquifer was 34.2 feet, which was approximately 4 percent of the average total observed change in groundwater-level altitude (groundwater level). Simulated spring flow representing Comanche Springs exhibits a pattern similar to observed spring flow. Independent geochemical modeling corroborates results of simulated groundwater flow that indicates groundwater in the Edwards-Trinity aquifer in the Leon-Belding and Fort Stockton areas is a mixture of recharge from the Barilla and Davis Mountains and groundwater that has upwelled from the Rustler aquifer.

Water-level altitudes 2014 and water-level changes in the Chicot, Evangeline, and Jasper aquifers and compaction 1973-2013 in the Chicot and Evangeline aquifers, Houston-Galveston region, Texas

Science.gov (United States)

Kasmarek, Mark C.; Johnson, Michaela R.; Ramage, Jason K.

2014-01-01

Most of the land-surface subsidence in the Houston-Galveston region, Texas, has occurred as a direct result of groundwater withdrawals for municipal supply, commercial and industrial use, and irrigation that depressured and dewatered the Chicot and Evangeline aquifers, thereby causing compaction of the aquifer sediments, mostly in the fine-grained clay and silt layers. This report, prepared by the U.S. Geological Survey 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, is one in an annual series of reports depicting water-level altitudes and water-level changes in the Chicot, Evangeline, and Jasper aquifers and measured compaction of subsurface sediments in the Chicot and Evangeline aquifers in the Houston-Galveston region. The report contains maps depicting approximate 2014 water-level altitudes (represented by measurements made during December 2013–March 2014) for the Chicot, Evangeline, and Jasper aquifers; maps depicting 1-year (2013–14) water-level changes for each aquifer; maps depicting contoured 5-year (2009–14) water-level changes for each aquifer; maps depicting contoured long-term (1990–2014 and 1977–2014) water-level changes for the Chicot and Evangeline aquifers; a map depicting contoured long-term (2000–14) water-level changes for the Jasper aquifer; a map depicting locations of borehole-extensometer sites; and graphs depicting measured cumulative compaction of subsurface sediments at the borehole extensometers during 1973–2013. Tables listing the data used to construct each water-level map for each aquifer and the compaction graphs are included.

Water-level altitudes 2012 and water-level changes in the Chicot, Evangeline, and Jasper aquifers and compaction 1973-2011 in the Chicot and Evangeline aquifers, Houston-Galveston region, Texas

Science.gov (United States)

Kasmarek, Mark C.; Johnson, Michaela R.; Ramage, Jason K.

2012-01-01

Most of the subsidence in the Houston–Galveston region, Texas, has occurred as a direct result of groundwater withdrawals for municipal supply, commercial and industrial use, and irrigation that depressured and dewatered the Chicot and Evangeline aquifers and caused compaction of the clay layers of the aquifer sediments. This report—prepared by the U.S. Geological Survey 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—is one in an annual series of reports depicting water-level altitudes and water-level changes in the Chicot, Evangeline, and Jasper aquifers and compaction in the Chicot and Evangeline aquifers in the Houston–Galveston region. The report contains maps showing approximate water-level altitudes for 2012 (calculated from measurements of water levels in wells made during December 2011–February 2012) for the Chicot, Evangeline, and Jasper aquifers; maps showing 1-year (2011–12) water-level-altitude changes for each aquifer; maps showing 5-year (2007–12) water-levelaltitude changes for each aquifer; maps showing long-term (1990–2012 and 1977–2012) water-level-altitude changes for the Chicot and Evangeline aquifers; a map showing long-term (2000–12) water-level-altitude change for the Jasper aquifer; a map showing locations of borehole extensometer sites; and graphs showing measured compaction of subsurface sediments at the extensometers from 1973 (or later) through 2011. Tables listing the data that were used to construct each water-level map for each aquifer and the cumulative compaction graphs are included.

Sequence-Stratigraphic Analysis of the Regional Observation Monitoring Program (ROMP) 29A Test Corehole and Its Relation to Carbonate Porosity and Regional Transmissivity in the Floridan Aquifer System, Highlands County, Florida

Science.gov (United States)

Ward, W. C.; Cunningham, K.J.; Renken, R.A.; Wacker, M.A.; Carlson, J.I.

2003-01-01

An analysis was made to describe and interpret the lithology of a part of the Upper Floridan aquifer penetrated by the Regional Observation Monitoring Program (ROMP) 29A test corehole in Highlands County, Florida. This information was integrated into a one-dimensional hydrostratigraphic model that delineates candidate flow zones and confining units in the context of sequence stratigraphy. Results from this test corehole will serve as a starting point to build a robust three-dimensional sequence-stratigraphic framework of the Floridan aquifer system. The ROMP 29A test corehole penetrated the Avon Park Formation, Ocala Limestone, Suwannee Limestone, and Hawthorn Group of middle Eocene to Pliocene age. The part of the Avon Park Formation penetrated in the ROMP 29A test corehole contains two composite depositional sequences. A transgressive systems tract and a highstand systems tract were interpreted for the upper composite sequence; however, only a highstand systems tract was interpreted for the lower composite sequence of the deeper Avon Park stratigraphic section. The composite depositional sequences are composed of at least five high-frequency depositional sequences. These sequences contain high-frequency cycle sets that are an amalgamation of vertically stacked high-frequency cycles. Three types of high-frequency cycles have been identified in the Avon Park Formation: peritidal, shallow subtidal, and deeper subtidal high-frequency cycles. The vertical distribution of carbonate-rock diffuse flow zones within the Avon Park Formation is heterogeneous. Porous vuggy intervals are less than 10 feet, and most are much thinner. The volumetric arrangement of the diffuse flow zones shows that most occur in the highstand systems tract of the lower composite sequence of the Avon Park Formation as compared to the upper composite sequence, which contains both a backstepping transgressive systems tract and a prograding highstand systems tract. Although the porous and permeable

Hydrodynamic framework of Saharan Triassic aquifers in South Tunisia and Algeria

Science.gov (United States)

Dhia, H. Ben; Chiarelli, A.

The main characteristics of the lower Triassic in the Saharan part of Tunisia are presented. This first study of the aquifer is made possible because of data available from numerous petroleum wells that exist in the region. The results show that the reservoir is of importance for either geothermal energy recovering or human water needs; especially since its salinity lies in the range 2 g/l to 60 g/l. Along the Tunisian-Llibyan frontier, because of its pressure and salinity (<3 g/l), the aquifer can be used for regional needs. The study also shows that the salinity gradient (SE-NW) increases orthogonally to the runoff direction (SW-NE). This phenomenon was unexpected and it is necessary to consider the aquifer in its regional North African framework and to include its Algerian part to understand it; when the salinity and potentiometric maps include both countries, a regional pattern is evident. Furthermore, a correspondence is noted between the salinity variations and the percentage of detritic elements in the reservoir. Salinity increases toward the NW, while the detritic elements decrease in that direction. Zones with salt content lower than 5 g/l seem to be related to good reservoirs and shales, that are rich in sands, and carbonates. The aquifer water supply is primarily linked to gravity flow and secondarily to compaction flow.

Planning report for the Gulf Coast Regional Aquifer-System Analysis in the Gulf of Mexico coastal plain, United States

Science.gov (United States)

Grubb, Hayes F.

1984-01-01

Large quantities of water for municipal, industrial and agriculture use are supplied from the aquifers in Tertiary and younger sediments over an area of about 225,000 square miles in the Coastal Plain of Alabama, Arkansas, Florida, Illinois, Kentucky, Louisiana, Mississippi, Missouri, Tennessee, and Texas. Three regional aquifer systems, the Mississippi Embayment aquifer system, the Coastal Lowlands aquifer system, and the Texas Coastal Uplands aquifer system have been developed to varying degrees throughout the area. A variety of problems has resulted from development such as movement of the saline-freshwater interface into parts of aquifers that were previously fresh, lowering of the potentiometric surface with resulting increases in pumping lift, and land-surface subsidence due to the compaction of clays within the aquifer. Increased demand for ground water is anticipated to meet the needs of urban growth, expanded energy development, and growth of irrigated agriculture. The U. S. Geological Survey initiated an eightyear study in 1981 to define the geohydrologic framework, describe the chemistry of the ground water, and to analyze the regional ground-water flow patterns. The objectives, plan, and organization of the study are described in this report and the major tasks to be undertaken are outlined.

Evidence for thermal convection in the deep carbonate aquifer of the eastern sector of the Po Plain, Italy

Science.gov (United States)

Pasquale, V.; Chiozzi, P.; Verdoya, M.

2013-05-01

Temperatures recorded in wells as deep as 6 km drilled for hydrocarbon prospecting were used together with geological information to depict the thermal regime of the sedimentary sequence of the eastern sector of the Po Plain. After correction for drilling disturbance, temperature data were analyzed through an inversion technique based on a laterally constant thermal gradient model. The obtained thermal gradient is quite low within the deep carbonate unit (14 mK m- 1), while it is larger (53 mK m- 1) in the overlying impermeable formations. In the uppermost sedimentary layers, the thermal gradient is close to the regional average (21 mK m- 1). We argue that such a vertical change cannot be ascribed to thermal conductivity variation within the sedimentary sequence, but to deep groundwater flow. Since the hydrogeological characteristics (including litho-stratigraphic sequence and structural setting) hardly permit forced convection, we suggest that thermal convection might occur within the deep carbonate aquifer. The potential of this mechanism was evaluated by means of the Rayleigh number analysis. It turned out that permeability required for convection to occur must be larger than 3 10- 15 m2. The average over-heat ratio is 0.45. The lateral variation of hydrothermal regime was tested by using temperature data representing the aquifer thermal conditions. We found that thermal convection might be more developed and variable at the Ferrara High and its surroundings, where widespread fracturing may have increased permeability.

Isotope characterization of shallow aquifers in the Horombe region, South of Madagascar

International Nuclear Information System (INIS)

Fareze, L.P.; Rajaobelison, J.; Ramaroson, V.; Raoelina Andriambololona; Andriamiarintsoa, G.; Razafitsalama, P.R.; Rahobisoa, J.J.; Randrianarison, H.; Ranaivoarisoa, A.; Marah, H.

2011-01-01

The present study deals with the problem of evaluation of the recharge mechanism and the characterization of the groundwater flow system in the basement shallow aquifer, which is one of the groundwater resource in the semi-arid South region of Madagascar. Stable isotopes (deuterium and oxygen-18) and tritium are used to achieve with accuracy the hydrogeological and geochemical dynamics study. Chemical analysis is used to provide complementary information to the investigation. A space distribution of tritium concentration and isotopic composition in groundwater shows evidence of two opposite categories of aquifers, which is confirmed by the chemical analysis results and by the geological features of the study site. Some groundwater flow path directions have been identified in the study area thanks to the tritium concentration space distribution and the geological formation. Besides, the groundwater recharge of the shallow aquifers in the South of Madagascar has been characterized by the exponential mixing model.

Carbon dynamics in a Late Quaternary-age coastal limestone aquifer system undergoing saltwater intrusion.

Science.gov (United States)

Bryan, Eliza; Meredith, Karina T; Baker, Andy; Andersen, Martin S; Post, Vincent E A

2017-12-31

This study investigates the inorganic and organic aspects of the carbon cycle in groundwaters throughout the freshwater lens and transition zone of a carbonate island aquifer and identifies the transformation of carbon throughout the system. We determined 14 C and 13 C carbon isotope values for both DIC and DOC in groundwaters, and investigated the composition of DOC throughout the aquifer. In combination with hydrochemical and 3 H measurements, the chemical evolution of groundwaters was then traced from the unsaturated zone to the deeper saline zone. The data revealed three distinct water types: Fresh (F), Transition zone 1 (T1) and Transition zone 2 (T2) groundwaters. The 3 H values in F and T1 samples indicate that these groundwaters are mostly modern. 14 C DOC values are higher than 14 C DIC values and are well correlated with 3 H values. F and T1 groundwater geochemistry is dominated by carbonate mineral recrystallisation reactions that add dead carbon to the groundwater. T2 groundwaters are deeper, saline and characterised by an absence of 3 H, lower 14 C DOC values and a different DOC composition, namely a higher proportion of Humic Substances relative to total DOC. The T2 groundwaters are suggested to result from either the slow circulation of water within the seawater wedge, or from old remnant seawater caused by past sea level highstands. While further investigations are required to identify the origin of the T2 groundwaters, this study has identified their occurrence and shown that they did not evolve along the same pathway as fresh groundwaters. This study has also shown that a combined approach using 14 C and 13 C carbon isotope values for both DIC and DOC and the composition of DOC, as well as hydrochemical and 3 H measurements, can provide invaluable information regarding the transformation of carbon in a groundwater system and the evolution of fresh groundwater recharge. Copyright © 2017 Elsevier B.V. All rights reserved.

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

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....... 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...

Screening for suitable areas for Aquifer Thermal Energy Storage within the Brussels Capital Region, Belgium using coupled groundwater flow and heat transport modelling tools

Science.gov (United States)

Anibas, Christian; Kukral, Janik; Touhidul Mustafa, Syed Md; Huysmans, Marijke

2017-04-01

Urban areas have a great potential for shallow geothermal systems. Their energy demand is high, but currently they have only a limited potential to cover their own energy demand. The transition towards a low-carbon energy regime offers alternative sources of energy an increasing potential. Urban areas however pose special challenges for the successful exploitation of shallow geothermal energy. High building densities limit the available space for drillings and underground investigations. Urban heat island effects and underground structures influence the thermal field, groundwater pollution and competing water uses limit the available subsurface. To tackle these challenges in the Brussels Capital Region, Belgium two projects 'BruGeo' and the recently finished 'Prospective Research of Brussels project 2015-PRFB-228' address the investigation in urban geothermal systems. They aim to identify the key factors of the underground with respect to Aquifer Thermal Energy Storage (ATES) installations like thermal properties, aquifer thicknesses, groundwater flow velocities and their heterogeneity. Combined numerical groundwater and heat transport models are applied for the assessment of both open and closed loop shallow geothermal systems. The Brussels Capital Region comprises of the Belgian Capital, the City of Brussels and 18 other municipalities covering 161 km2 with almost 1.2 million inhabitants. Beside the high population density the Brussels Capital Region has a pronounced topography and a relative complex geology. This is both a challenge and an opportunity for the exploitation of shallow geothermal energy. The most important shallow hydrogeological formation in the Brussels-Capital Region are the Brussels Sands with the Brussels Sands Aquifer. Scenarios where developed using criteria for the hydrogeological feasibility of ATES installations such as saturated aquifer thickness, groundwater flow velocity and the groundwater head below surface. The Brussels Sands

Carbon, metals and grain size correlate with bacterial community composition in sediments of a high arsenic aquifer

Directory of Open Access Journals (Sweden)

Teresa eLegg

2012-03-01

Full Text Available Bacterial communities can exert significant influence on the biogeochemical cycling of arsenic (As. This has globally important implications since As toxicity in drinking water affects the health of millions of people worldwide, including in the Ganges-Brahmaputra Delta region of Bangladesh where geogenic groundwater arsenic concentrations can be more than 10 times the World Health Organization’s limit. Thus, the goal of this research was to investigate patterns in bacterial community composition across environmental gradients in an aquifer with elevated groundwater As concentrations in Araihazar, Bangladesh. We characterized the bacterial community by pyrosequencing 16S rRNA genes from aquifer sediment samples collected at three locations along a groundwater flowpath, at a range of depths between 1.5 and 15 m. We identified significant shifts in bacterial community composition along the groundwater flowpath in the aquifer. In addition, we found that bacterial community structure was significantly related to sediment grain size, and sediment carbon (C, manganese (Mn, and iron (Fe concentrations. Deltaproteobacteria and Chloroflexi were more abundant in silty sediments with higher concentrations of C, Fe, and Mn. By contrast, Alphaproteobacteria and Betaproteobacteria were more abundant in sediments with higher concentrations of sand and Si, and lower concentrations of C and metals. Based on the phylogenetic affiliations of these taxa, these results may indicate a shift to more Fe-, Mn-, and humic substance- reducers in the high C and metal sediments. It is well-documented that C, Mn and Fe may influence the mobility of groundwater arsenic, and it is intriguing that these constituents may also structure the bacterial community.

Characterization of the Cretaceous aquifer structure of the Meskala region of the Essaouira Basin, Morocco

Science.gov (United States)

Hanich, L.; Zouhri, L.; Dinger, J.

2011-01-01

The aquifer of early Cretaceous age in the Meskala region of the Essaouira Basin is defined by interpretation of geological drilling data of oil and hydrogeological wells, field measurement and analysis of in situ fracture orientations, and the application of a morphostructural method to identify lineaments. These analyzes are used to develop a stratigraphic-structural model of the aquifer delimited by fault zones of two principal orientations: NNE and WNW. These fault zones define fault blocks that range in area from 4 to 150km2. These blocks correspond either to elevated zones (horsts) or depressed zones (grabens). This structural setting with faults blocks of Meskala region is in accordance with the structure of the whole Essaouira Basin. Fault zones disrupt the continuity of the aquifer throughout the study area, create recharge and discharge zones, and create dip to the units from approximately 10?? to near vertical in various orientations. Fracture measurements and morphometric-lineament analyzes help to identify unmapped faults, and represent features important to groundwater hydraulics and water quality within fault blocks. The above geologic features will enable a better understanding of the behaviour and hydro-geo-chemical and hydrodynamics of groundwater in the Meskala aquifer. ?? 2010 Elsevier Ltd.

A practical assessment of aquifer discharge for regional groundwater demand by characterizing leaky confined aquifer overlain on a Mesozoic granitic gneiss basement

Science.gov (United States)

Shih, David Ching-Fang

2018-04-01

Due to increasing population worldwide, there is an urgent need to manage these important but diminishing groundwater resources efficiently to ensure their continued availability. The major innovative design of this study is to provide a practical assessment process for groundwater discharge under a regional demand by characterizing the nature of leaky confined aquifers overlain on a Mesozoic granitic gneiss basement which involves the important groundwater system in the Kinmen region (Taiwan, ROC) and the assessment of adoptable groundwater discharge in aquifer is needed. The storage coefficient presents an order of one in a thousand and hydraulic conductivity is approximately at the order of 1-8 m/d and 0.4-0.9 m/d for aquifer and aquitard respectively. Groundwater discharge and admissible number of pumping well is suggested considering scheduled maximum groundwater volume and head decline change for eastern and western studied area respectively. The safety subjected to the conservative issue is then addressed by the use of scheduled maximum groundwater volume. It reveals that the safety can be ensured using the indicator as scheduled maximum groundwater volume with predefined scenarios. The result can be utilized practically for developing management strategy of groundwater resources due to the applicability and novel of method.

Regional Management of an Aquifer for Mining Under Fuzzy Environmental Objectives

Science.gov (United States)

BogáRdi, IstváN.; BáRdossy, AndráS.; Duckstein, Lucien

1983-12-01

A methodology is developed for the dynamic multiobjective management of a multipurpose regional aquifer. In a case study of bauxite mining in Western Hungary, ore deposits are often under the piezometric level of a karstic aquifer, while this same aquifer also provides recharge flows for thermal springs. N + 1 objectives are to be minimized, the first one being total discounted cost of control by dewatering or grouting; the other N objectives consist of the flow of thermal springs at N control points. However, there is no agreement among experts as to a set of numerical values that would constitute a "sound environment"; for this reason a fuzzy set analysis is used, and the N environmental objectives are combined into a single fuzzy membership function. The constraints include ore availability, various capacities, and the state transition function that describes the behavior of both piezometric head and underground flow. The model is linearized and solved as a biobjective dynamic program by using multiobjective compromise programming. A numerical example with N = 2 appears to lead to realistic control policies. Extension of the model to the nonlinear case is discussed.

Nuclear applications for the management of aquifers in the semi-arid region

International Nuclear Information System (INIS)

Simoes Filho, Fernando Lamego

2005-01-01

The semi-arid region of the Northeast of Brazil is characterized by a lack of superficial waters due to the low pluviometric precipitation and high evaporation rates. In addition to this, the precipitation events are irregular in time causing long periods of dryness or flooding with catastrophic consequences. Owing to adverse climatic conditions with recurrent droughts, intense pressure is being put on the use of groundwater resources. Groundwater occurrence on its turn depends on a series of geological and climatological characteristics that are very variable in the region. Because of this situation, groundwater is of strategical importance and represents a vital factor to its socioeconomic development. However, there is still insufficient knowledge of the basic aquifers characteristics leading to an over exploitation of the water resources. It is not surprising that, amongst other reasons, this situation contributes to the fact that areas with the lowest human development pattern are located in the semi-arid region of Brazil. Given the nature of hydrological problems that need to be addressed in semi-arid regions, nuclear/isotope techniques are increasingly recognized as indispensable tools for water resources assessment and development. However, information arising from these techniques has to cope with other hydrological methods in an integrated manner. The general objective was prospect nuclear technologies as tools for aquifer management, promoting sustainable use of groundwater in the semi-arid region. (author)

Hydrogeologic assessment of shallow clastic and carbonate rock aquifers in Hendry and Collier counties, southwestern Florida

Science.gov (United States)

Brown, C. Erwin; Krulikas, R.K.; Brendle, D.L.

1996-01-01

Direct-current electrical resistivity data were collected from 109 vertical electrical sounding sites in Hendry and Collier Counties, southwestern Florida. Selected direct-current electrical resistivity surveys, together with available borehole geologic and geophysical data, were used to determine the approximate areal extent of the shallow clastic aquifers composed of thick sands and carbonate lithologies. Results indicated that a complex pattern of shallow sands, clays, and carbonate lithologies occur throughout the area. Buried channel sands were found as deep as 50 meters below land surface in some places. The channels contain unconsolidated fine- to medium-grained quartz sand interbedded with sandy limestone, shell fragments, and gray-green sandy clay. Both surface and borehole geophysical techniques with lithologic data were necessary to approximately locate and define layers that might behave as confining layers and to locate and define the extent of any buried sand aquifers. The borehole geophysical data were used to analyze the zones of higher resistivity. Direct-current electrical resistivity data indicated the approximate location of certain layer boundaries. The conjunctive use of natural gamma and short- and long-normal resistivity logs was helpful in determining lithologic effects. Geohydrologic sections were prepared to identify potential locations of buried channels and carbonates containing freshwater. Buried channel sands and carbonate rock sections were identified in the subsurface that potentially may contain freshwater supplies.

Hydrogeological study of the aquifer system of the northern Sahara in the Algero-Tunisian border: A case study of Oued Souf region

Science.gov (United States)

Halassa, Younes; Zeddouri, Aziez; Mouhamadou, Ould Babasy; Kechiched, Rabah; Benhamida, Abdeldjebbar Slimane

2018-05-01

The aquifer system in The Algero-Tunisian border and Chotts region is mainly composed of two aquifers: The first is the Complex Terminal (CT) and the second is the Intercalary aquifer (CI). This study aims the identification and spatial evolution of factors that controlling the water quality in the Complex Terminal aquifer (CT) in the Chotts region (Oued Souf region - Southeastern of Algeria). The concentration of major elements, temperature, pH and salinity were monitored during 2015 in 34 wells from the CT aquifer. The geological, geophysical, hydrogeological and hydrochemical methods were applied in order to carried out a model for the investigated aquifer system and to characterize the hydrogeological and the geochemical behavior, as well as the geometrical and the lithological configuration. Multivariate statistical analyses such as Principal Component Analysis (PCA) were also used for the treatment of several data. Results show that the salinity follows the same regional distribution of Chloride, Sodium, Magnesium, Sulfate and Calcium. Note that the salinity shows low contents in the upstream part of investigated region suggesting restricted dissolution of salts. Hydro-chemical study and saturation indexes highlight the dominance of the dissolution and the precipitation of calcite, dolomite, anhydrite, gypsum and halite. The PCA analysis indicates that Na+, Cl-, Ca2+, Mg2+, SO42- and K+ variables that influence the water mineralization.

Reactions and reaction rates in the regional aquifer beneath the Pajarito Plateau, north-central New Mexico, USA

Science.gov (United States)

Hereford, Anne G.; Keating, Elizabeth H.; Guthrie, George D.; Zhu, Chen

2007-05-01

Reactions and reaction rates within aquifers are fundamental components of critical hydrological processes. However, reactions simulated in laboratory experiments typically demonstrate rates that are much faster than those observed in the field. Therefore, it is necessary to conduct more reaction rate analyses in natural settings. This study of geochemical reactions in the regional aquifer in the Pajarito Plateau near Los Alamos, New Mexico combines modeling with petrographic assessment to further knowledge and understanding of complex natural hydrologic systems. Groundwater geochemistry shows marked evolution along assumed flow paths. The flow path chosen for this study was evaluated using inverse mass balance modeling to calculate the mass transfer. X-ray diffraction and field emission gun scanning electron microscopy were used to identify possible reactants and products. Considering the mineralogy of the aquifer and saturation indices for the regional water refined initial interpretations. Calculations yielded dissolution rates for plagioclase on the order of 10-15 mol s-1 m-2 and for K-feldspar on the order of 10-17 mol s-1 m-2, orders of magnitude slower than laboratory rates. While these rates agree with other aquifer studies, they must be considered in the light of the uncertainty associated with geometric surface area estimates, 14C ages, and aquifer properties.

Impact of river stage prediction methods on stream-aquifer exchanges in a hydro(geo)logical model at the regional scale

Science.gov (United States)

Saleh, F.; Flipo, N.; de Fouquet, C.

2012-04-01

The main objective of this study is to provide a realistic simulation of river stage in regional river networks in order to improve the quantification of stream-aquifer exchanges and better assess the associated aquifer responses that are often impacted by the magnitude and the frequency of the river stage fluctuations. The study focuses on the Oise basin (17 000 km2, part of the 65 000 km2 Seine basin in Northern France) where stream-aquifer exchanges cannot be assessed directly by experimental methods. Nowadays numerical methods are the most appropriate approaches for assessing stream-aquifer exchanges at this scale. A regional distributed process-based hydro(geo)logical model, Eau-Dyssée, is used, which aims at the integrated modeling of the hydrosystem to manage the various elements involved in the quantitative and qualitative aspects of water resources. Eau-Dyssée simulates pseudo 3D flow in aquifer systems solving the diffusivity equation with a finite difference numerical scheme. River flow is simulated with a Muskingum model. In addition to the in-stream discharge, a river stage estimate is needed to calculate the water exchange at the stream-aquifer interface using the Darcy law. Three methods for assessing in-stream river stages are explored to determine the most appropriate representation at regional scale over 25 years (1980-2005). The first method consists in defining rating curves for each cell of a 1D Saint-Venant hydraulic model. The second method consists in interpolating observed rating curves (at gauging stations) onto the river cells of the hydro(geo)logical model. The interpolation technique is based on geostatistics. The last method assesses river stage using Manning equation with a simplified rectangular cross-section (water depth equals the hydraulic radius). Compared to observations, the geostatistical and the Manning methodologies lead to slightly less accurate (but still acceptable) results offering a low computational cost opportunity

Microcosm studies on iron and arsenic mobilization from aquifer sediments under different conditions of microbial activity and carbon source

Science.gov (United States)

Duan, Mengyu; Xie, Zuoming; Wang, Yanxin; Xie, Xianjun

2009-05-01

Microcosm experiments were conducted to understand the mechanism of microbially mediated mobilization of Fe and As from high arsenic aquifer sediments. Arsenic-resistant strains isolated from aquifer sediments of a borehole specifically drilled for this study at Datong basin were used as inoculated strains, and glucose and sodium acetate as carbon sources for the experiments. In abiotic control experiments, the maximum concentrations of Fe and As were only 0.47 mg/L and 0.9 μg/L, respectively. By contrast, the maximum contents of Fe and As in anaerobic microcosm experiments were much higher (up to 1.82 mg/L and 12.91 μg/L, respectively), indicating the crucial roles of microbial activities in Fe and As mobilization. The observed difference in Fe and As release with different carbon sources may be related to the difference in growth pattern and composition of microbial communities that develop in response to the type of carbon sources.

Carbon Sequestration in Saline Aquifers: Modeling Diffusive and Convective Transport Of a Carbon-­Dioxide Cap

KAUST Repository

Allen, Rebecca

2011-05-01

An increase in the earth’s surface temperature has been directly linked to the rise of carbon dioxide (CO2) levels In the atmosphere and an enhanced greenhouse effect. CO2 sequestration is one of the proposed mitigation Strategies in the effort to reduce atmospheric CO2 concentrations. Globally speaking, saline aquifers provide an adequate storage capacity for the world’s carbon emissions, and CO2 sequestration projects are currently underway in countries such as Norway, Germany, Japan, USA, and others. Numerical simulators serve as predictive tools for CO2 storage, yet must model fluid transport behavior while coupling different transport processes together accurately. With regards to CO2 sequestration, an extensive amount of research has been done on the diffusive-convective transport that occurs under a cap of CO2-saturated fluid, which results after CO2 is injected into an aquifer and spreads laterally under an area of low permeability. The diffusive-convective modeling reveals an enhanced storage capacity in saline aquifers, due to the density increase between pure fluid and CO2‐saturated fluid. This work presents the transport modeling equations that are used for diffusive- convective modeling. A cell-centered finite difference method is used, and simulations are run using MATLAB. Two cases are explored in order to compare the results from this work’s self-generated code with the results published in literature. Simulation results match relatively well, and the discrepancy for a delayed onset time of convective transport observed in this work is attributed to numerical artifacts. In fact, onset time in this work is directly attributed to the instability of the physical system: this instability arises from non-linear coupling of fluid flow, transport, and convection, but is triggered by numerical errors in these simulations. Results from this work enable the computation of a value for the numerical constant that appears in the onset time equation that

Hydraulic properties and scale effects investigation in regional rock aquifers, south-western Quebec, Canada

Science.gov (United States)

Nastev, M.; Savard, M. M.; Lapcevic, P.; Lefebvre, R.; Martel, R.

This paper reports on the characterization of hydraulic properties of regional rock aquifers carried out within a groundwater resources assessment project in the St. Lawrence Lowlands of south-western Quebec. To understand the aquifer behavior at both the fracture level and at field scale, hydraulic investigations were carried out using various aquifer tests. The groundwater flow at the local scale is controlled mostly by the fracture system. Results of the constant-head injection tests show a weak decreasing trend of hydraulic conductivity with depth indicating that a major part of the groundwater flow occurs in the first meters of the rock sequence. At the regional scale, the equivalent porous media approach is applicable. The hydraulic conductivity measurements were correlated to the scale of the aquifer tests expressed with the investigated aquifer volume. A simple interpolation procedure for the hydraulic conductivity field was developed based on the distance between field measurements and the tested aquifer volumes. The regional distribution of the hydraulic conductivity for the major fractured aquifer units indicates that dolostone is the most permeable whereas sandstone and crystalline rocks are the least permeable units. Este artículo trata de la caracterización de las propiedades hidráulicas en acuíferos regionales rocosos, la cual se llevó a cabo dentro del proyecto de evaluación de los recursos de agua subterránea en St. Lawrence Lowlands al suroeste de Quebec. Para entender el comportamiento del acuífero tanto a nivel de fractura como a escala del campo, se ejecutaron investigaciones hidráulicas usando varias pruebas de acuífero. El flujo del agua subterránea a escala local está controlado principalmente por el sistema de fracturas. Los resultados de las pruebas de inyección con cabeza constante muestran una tendencia decreciente débil de la conductividad hidráulica con la profundidad, indicando que la mayor parte del flujo de agua

Well-based stable carbon isotope leakage monitoring of an aquifer overlying the CO2 storage reservoir at the Ketzin pilot site, Germany

Science.gov (United States)

Nowak, Martin; Myrttinen, Anssi; Zimmer, Martin; van Geldern, Robert; Barth, Johannes A. C.

2014-05-01

At the pilot site for CO2 storage in Ketzin, a new well-based leakage-monitoring concept was established, comprising geochemical and hydraulic observations of the aquifer directly above the CO2 reservoir (Wiese et al., 2013, Nowak et al. 2013). Its purpose was to allow early detection of un-trapped CO2. Within this monitoring concept, we established a stable carbon isotope monitoring of dissolved inorganic carbon (DIC). If baseline isotope values of aquifer DIC (δ13CDIC) and reservoir CO2 (δ13CCO2) are known and distinct from each other, the δ13CDIC has the potential to serve as an an early indicator for an impact of leaked CO2 on the aquifer brine. The observation well of the overlying aquifer was equipped with an U-tube sampling system that allowed sampling of unaltered brine. The high alkaline drilling mud that was used during well drilling masked δ13CDIC values at the beginning of the monitoring campaign. However, subsequent monitoring allowed observing on-going re-equilibration of the brine, indicated by changing δ13CDIC and other geochemical values, until values ranging around -23 ‰ were reached. The latter were close to baseline values before drilling. Baselineδ13CDIC and δ13CCO2 values were used to derive a geochemical and isotope model that predicts evolution of δ13CDIC, if CO2 from the reservoir would leak into the aquifer. The model shows that equilibrium isotope fractionation would have to be considered if CO2 dissolves in the brine. The model suggests that stable carbon isotope monitoring is a suitable tool to assess the impact of injected CO2 in overlying groundwater aquifers. However, more data are required to close gaps of knowledge about fractionation behaviour within the CO2(g) - DIC system under elevated pressures and temperatures. Nowak, M., Myrttinen, A., Zimmer, M., Wiese, B., van Geldern, R., Barth, J.A.C., 2013. Well-based, Geochemical Leakage Monitoring of an Aquifer Immediately Above a CO2 Storage Reservoir by Stable Carbon

Potentiometric surface of the Upper Floridan aquifer in Florida and parts of Georgia, South Carolina, and Alabama, May – June 2010

Science.gov (United States)

Kinnaman, Sandra L.; Dixon, Joann F.

2011-01-01

The Floridan aquifer system covers nearly 100,000 square miles in the southeastern United States throughout Florida and in parts of Georgia, South Carolina, and Alabama, and is one of the most productive aquifers in the world (Miller, 1990). This sequence of carbonate rocks is hydraulically connected and is over 300 feet thick in south Florida and thins toward the north. Typically, this sequence is subdivided into the Upper Floridan aquifer, the middle confining unit, and the Lower Floridan aquifer. The majority of freshwater is contained in the Upper Floridan aquifer and is used for water supply (Miller, 1986). The Lower Floridan aquifer contains fresh to brackish water in northeastern Florida and Georgia, while in south Florida it is saline. The potentiometric surface of the Upper Floridan aquifer in May–June 2010 shown on this map was constructed as part of the U.S. Geological Survey Floridan Aquifer System Groundwater Availability Study (U.S. Geological Survey database, 2011). Previous synoptic measurements and regional potentiometric maps of the Upper Floridan aquifer were prepared for May 1980 (Johnston and others, 1981) and May 1985 (Bush and others, 1986) as part of the Floridan Regional Aquifer System Analysis.

Current knowledge and future research directions to link soil health and water conservation in the Ogallala Aquifer region.

Science.gov (United States)

The Ogallala Aquifer is one of the largest freshwater aquifers in the world. It acts as a valuable resource in agriculture, animal production, and public water supplies across eight Great Plains states. However, with high irrigation demand, low recharge rates across most of the region, and extreme c...

Water-level altitudes 2009 and water-level changes in the Chicot, Evangeline, and Jasper Aquifers and compaction 1973-2008 in the Chicot and Evangeline Aquifers, Houston-Galveston Region, Texas

Science.gov (United States)

Kasmarek, Mark C.; Houston, Natalie A.; Ramage, Jason K.

2009-01-01

This report, done in cooperation with the Harris-Galveston Subsidence District, the City of Houston, the Fort Bend Subsidence District, and the Lone Star Groundwater Conservation District, is one in an annual series of reports that depicts water-level altitudes and water-level changes in the Chicot, Evangeline, and Jasper aquifers, and compaction in the Chicot and Evangeline aquifers in the Houston-Galveston region, Texas. The report (excluding appendixes) contains 16 sheets and 15 tables: 3 sheets are maps showing current-year (2009) water-level altitudes for each aquifer, respectively; 3 sheets are maps showing 1-year (2008-09) water-level changes for each aquifer, respectively; 3 sheets are maps showing 5-year (2004-09) water-level changes for each aquifer, respectively; 4 sheets are maps showing long-term (1990-2009 and 1977-2009) water-level changes for the Chicot and Evangeline aquifers, respectively; 1 sheet is a map showing long-term (2000-2009) water-level change for the Jasper aquifer; 1 sheet is a map showing site locations of borehole extensometers; and 1 sheet comprises graphs showing measured compaction of subsurface material at the sites from 1973 or later through 2008, respectively. Tables listing the data used to construct the aquifer-data maps and the compaction graphs are included.

Managed Aquifer Recharge: from Local Research and Experiences to Regional Aquifer Storage and Recovery

Science.gov (United States)

Hendriks, D.; Faneca, M.; Oude Essink, G.; van Baaren, E.; Stuurman, R.; Delsman, J. R.; van Kempen, C.; de Louw, P.

2016-12-01

Many areas in the world experience periodic water shortages due to meteorological drought, salt water intrusion or over-exploitation of the water resources. Recently, it was established that the depletion of aquifers in many areas of the world is in an advanced state (Gleeson et al, 2012). This poses enormous challenges as 2.5 billion people and many companies depend on groundwater now and in the future (UN, 2015; ESG, 2016). A solution to increase robustness of water systems and prevent water shortage is subsurface storage of water during wet periods using Managed Aquifer Research (MAR). In addition to mitigation of water shortage, MAR can also reduce the occurrence and degree of flooding. Here, we present an overview of Deltares MAR expertise and available tools for up-scaling MAR. Deltares has experience with both research and implementation of MAR in different parts of the world under various hydro(geo)logical, climatic and socio-economic conditions. Various MAR techniques were assessed/tested in coastal areas of the Netherlands, Spain, New York, New Orleans and in Bangladesh. In some of these areas specific groundwater shortage related issues occur, such as salt water intrusion or subsidence. In Singapore, monitoring campaigns and modeling were done to design MAR by infiltration of water in over-exploited aquifers. In Abu Dhabi, geophysical methods were used to detect the optimal conditions for MAR systems. To effectively increase the robustness of groundwater systems up-scaling of MAR is required. For this purpose, Deltares developed tools that provide insight in the potential demand, possibilities and effectiveness of MAR at larger scales. The Quick scan tool for Fresh Groundwater Buffering provides insight on regional to national scale and is based on GIS-information of water demand, water resources, and subsurface properties. This quick scan tool has been applied for Mozambique, Kenya, India and Bangladesh. The Fresh Water Optimizer assesses the

Recent and old groundwater in the Niebla-Posadas regional aquifer (southern Spain): Implications for its management

Science.gov (United States)

Scheiber, Laura; Ayora, Carlos; Vázquez-Suñé, Enric; Cendón, Dioni I.; Soler, Albert; Custodio, Emilio; Baquero, Juan Carlos

2015-04-01

The Niebla-Posadas (NP) aquifer in southern Spain is one of the main groundwater sources for the lower Guadalquivir Valley, a semiarid region supporting an important population, agriculture and industry. To contribute to the understanding of this aquifer the assessment of sustainable use of groundwater, the residence time of groundwater in the NP aquifer has been estimated using 3H, 14C and 36Cl. Along the flow paths, recharged groundwater mixes with NaCl-type waters and undergoes calcite dissolution and is further modified by cation exchange (Ca-Na). Consequently, the water loses most of its calcium and the residual δ13CDIC in the groundwater is isotopically enriched. Further modifications take place along the flow path in deeper zones, where depleted δ13CDIC values are overprinted due to SO42- and iron oxide reduction, triggered by the presence of organic matter. Dating with 3H, 14C and 36Cl has allowed the differentiation of several zones: recharge zone (30 ky). An apparent link between the tectonic structure and the groundwater residence time zonation can be established. Regional faults clearly separates deep zone 1 from the distinctly older age (>30 ky) deep zone 2. From the estimated residence times, two groundwater areas of different behavior can be differentiated within the aquifer.

Salinization of aquifers at the regional scale by marine transgression: Time scales and processes

Science.gov (United States)

Armandine Les Landes, A.; Davy, P.; Aquilina, L.

2014-12-01

Saline fluids with moderate concentrations have been sampled and reported in the Armorican basement at the regional scale (northwestern France). The horizontal and vertical distributions of high chloride concentrations (60-1400mg/L) at the regional scale support the marine origin and provide constraints on the age of these saline fluids. The current distribution of fresh and "saline" groundwater at depth is the result mostly of processes occurring at geological timescales - seawater intrusion processes followed by fresh groundwater flushing -, and only slightly of recent anthropogenic activities. In this study, we focus on seawater intrusion mechanisms in continental aquifers. We argue that one of the most efficient processes in macrotidal environments is the gravity-driven downconing instability below coastal salinized rivers. 2-D numerical experiments have been used to quantify this process according to four main parameter types: (1) the groundwater system permeability, (2) the salinity degree of the river, (3) the river width and slope, and (4) the tidal amplitude. A general expression of the salinity inflow rates have been derived, which has been used to estimate groundwater salinization rates in Brittany, given the geomorphological and environmental characteristics (drainage basin area, river widths and slopes, tidal range, aquifer permeability). We found that downconing below coastal rivers entail very high saline rates, indicating that this process play a major role in the salinization of regional aquifers. This is also likely to be an issue in the context of climate change, where sea-level rise is expected.

Death Valley Lower Carbonate Aquifer Monitoring Program Wells Down gradient of the Proposed Yucca Mountain Nuclear Waste Repository

International Nuclear Information System (INIS)

Inyo County

2006-01-01

Inyo County has participated in oversight activities associated with the Yucca Mountain Nuclear Waste Repository since 1987. The overall goal of these studies are the evaluation of far-field issues related to potential transport, by ground water, or radionuclides into Inyo County, including Death Valley, and the evaluation of a connection between the Lower Carbonate Aquifer (LCA) and the biosphere. Our oversight and completed Cooperative Agreement research, and a number of other investigators research indicate that there is groundwater flow between the alluvial and carbonate aquifers both at Yucca Mountain and in Inyo County. In addition to the potential of radionuclide transport through the LCA, Czarnecki (1997), with the US Geological Survey, research indicate potential radionuclide transport through the shallower Tertiary-age aquifer materials with ultimate discharge into the Franklin Lake Playa in Inyo County. The specific purpose of this Cooperative Agreement drilling program was to acquire geological, subsurface geology, and hydrologic data to: (1) establish the existence of inter-basin flow between the Amargosa Basin and Death Valley Basin; (2) characterize groundwater flow paths in the LCA through Southern Funeral Mountain Range, and (3) Evaluation the hydraulic connection between the Yucca Mountain repository and the major springs in Death Valley through the LCA

Effects of regional groundwater flow on the performance of an aquifer thermal energy storage system under continuous operation

Science.gov (United States)

Lee, Kun Sang

2014-01-01

Numerical investigations and a thermohydraulic evaluation are presented for two-well models of an aquifer thermal energy storage (ATES) system operating under a continuous flow regime. A three-dimensional numerical model for groundwater flow and heat transport is used to analyze the thermal energy storage in the aquifer. This study emphasizes the influence of regional groundwater flow on the heat transfer and storage of the system under various operation scenarios. For different parameters of the system, performances were compared in terms of the temperature of recovered water and the temperature field in the aquifer. The calculated temperature at the producing well varies within a certain range throughout the year, reflecting the seasonal (quarterly) temperature variation of the injected water. The pressure gradient across the system, which determines the direction and velocity of regional groundwater flow, has a substantial influence on the convective heat transport and performance of aquifer thermal storage. Injection/production rate and geometrical size of the aquifer used in the model also impact the predicted temperature distribution at each stage and the recovery water temperature. The hydrogeological-thermal simulation is shown to play an integral part in the prediction of performance of processes as complicated as those in ATES systems.

Review of Aquifer Storage and Recovery Performance in the Upper Floridan Aquifer in Southern Florida

Science.gov (United States)

Reese, Ronald S.

2006-01-01

Introduction: Interest and activity in aquifer storage and recovery (ASR) in southern Florida has increased greatly during the past 10 to 15 years. ASR wells have been drilled to the carbonate Floridan aquifer system at 30 sites in southern Florida, mostly by local municipalities or counties located in coastal areas. The primary storage zone at these sites is contained within the brackish to saline Upper Floridan aquifer of the Floridan aquifer system. The strategy for use of ASR in southern Florida is to store excess freshwater available during the wet season in an aquifer and recover it during the dry season when needed for supplemental water supply. Each ASR cycle is defined by three periods: recharge, storage, and recovery. This fact sheet summarizes some of the findings of a second phase retrospective assessment of existing ASR facilities and sites.

Developing a probability-based model of aquifer vulnerability in an agricultural region

Science.gov (United States)

Chen, Shih-Kai; Jang, Cheng-Shin; Peng, Yi-Huei

2013-04-01

SummaryHydrogeological settings of aquifers strongly influence the regional groundwater movement and pollution processes. Establishing a map of aquifer vulnerability is considerably critical for planning a scheme of groundwater quality protection. This study developed a novel probability-based DRASTIC model of aquifer vulnerability in the Choushui River alluvial fan, Taiwan, using indicator kriging and to determine various risk categories of contamination potentials based on estimated vulnerability indexes. Categories and ratings of six parameters in the probability-based DRASTIC model were probabilistically characterized according to the parameter classification methods of selecting a maximum estimation probability and calculating an expected value. Moreover, the probability-based estimation and assessment gave us an excellent insight into propagating the uncertainty of parameters due to limited observation data. To examine the prediction capacity of pollutants for the developed probability-based DRASTIC model, medium, high, and very high risk categories of contamination potentials were compared with observed nitrate-N exceeding 0.5 mg/L indicating the anthropogenic groundwater pollution. The analyzed results reveal that the developed probability-based DRASTIC model is capable of predicting high nitrate-N groundwater pollution and characterizing the parameter uncertainty via the probability estimation processes.

The Implication of Agricultural Expansion on the Groundwater Flow Regime of Saq Aquifer in Al Qassim Region, Saudi Arabia

Science.gov (United States)

Alharbi, T.; Mansour Helmy, B. M.

2017-12-01

Al-Qassim Region in Saudi Arabia is characterized by expanding agricultural activities. Most agricultural fields are irrigated by groundwater, mainly from the Saq aquifer. Excessive water extraction from this aquifer and arid climatic conditions negatively alter the quality and quantity of the groundwater. In this study, detailed hydrological and hydrogeological investigations were carried out to characterize spatially the potential groundwater recharge zones, deal with the estimation of groundwater balance of the Saq aquifer in the study area and to assess the safe yield of the aquifer. Accordingly, the implication of agricultural expansion on groundwater flow regime of Saq aquifer and its relation with safe yield and groundwater recharge was evaluated. The water-budget was calculated and the main water Inputs and outputs were measured. Change detections of agricultural areas in the region for years, 1983, 1995 and 2005 were conducted using Landsat Satellite images and results were compared to water levels for same years. There are two potential recharge zones for Saq aquifer in the area, both are structurally controlled. The first zone is the outlet of wadi Ar Risha basin in south-eastern corner of the study area. The second is the western water divide of wadi Turfiya basin in the North west. Results of the study also indicated that 96.4 % of the total abstraction is consumed for agriculture supply. The present abstractions exceed both recharge and safe yield of the aquifer system, thus the aquifer is overexploited and mined. The average decrease in groundwater storage during the year 1983-2005 was estimated to be 33.4 Mm3, representing an average yearly decline of 1.98 m of the water table.

A multi-method approach for groundwater resource assessment in coastal carbonate (karst) aquifers: the case study of Sierra Almijara (southern Spain)

Science.gov (United States)

Andreo, B.; Barberá, J. A.; Mudarra, M.; Marín, A. I.; García-Orellana, J.; Rodellas, V.; Pérez, I.

2018-02-01

Understanding the transference of water resources within hydrogeological systems, particularly in coastal aquifers, in which groundwater discharge may occur through multiple pathways (through springs, into rivers and streams, towards the sea, etc.), is crucial for sustainable groundwater use. This research aims to demonstrate the usefulness of the application of conventional recharge assessment methods coupled to isotopic techniques for accurately quantifying the hydrogeological balance and submarine groundwater discharge (SGD) from coastal carbonate aquifers. Sierra Almijara (Southern Spain), a carbonate aquifer formed of Triassic marbles, is considered as representative of Mediterranean coastal karst formations. The use of a multi-method approach has permitted the computation of a wide range of groundwater infiltration rates (17-60%) by means of direct application of hydrometeorological methods (Thornthwaite and Kessler) and spatially distributed information (modified APLIS method). A spatially weighted recharge rate of 42% results from the most coherent information on physiographic and hydrogeological characteristics of the studied system. Natural aquifer discharge and groundwater abstraction have been volumetrically quantified, based on flow and water-level data, while the relevance of SGD was estimated from the spatial analysis of salinity, 222Rn and the short-lived radium isotope 224Ra in coastal seawater. The total mean aquifer discharge (44.9-45.9 hm3 year-1) is in agreement with the average recharged groundwater (44.7 hm3 year-1), given that the system is volumetrically equilibrated during the study period. Besides the groundwater resources assessment, the methodological aspects of this research may be interesting for groundwater management and protection strategies in coastal areas, particularly karst environments.

Results of a hydrogeological and hydrogeochemical study of a semi-arid karst aquifer in Tezbent plateau, Tebessa region, northeast of Algeria

Science.gov (United States)

Belfar, Dalila; Fehdi, Chemseddine; Baali, Fethi; Salameh, Elias

2017-06-01

The Hammamet Plain, situated in the northwest of the Tezbent mountain range, northeast of Algeria, drains carbonate aquifers through some important karst springs. The physical and chemical characteristics of spring and well water samples were studied for 2 years to assess the origin of groundwater and determine the factors driving the geochemical composition. The ionic speciation and mineral dissolution/precipitation was calculated. Water wells, characterizing groundwater circulation at shallow depths, are moderate to high mineralized waters of Na-HCO3 type. In contrast to the shallow environment, the CO2-rich, deeper waters are of the Ca-HCO3-SO4 type and undergo significant changes in the baseline chemistry along flow lines with increasing residence time. The main factors controlling the groundwater composition and its seasonal variations are the geology, because of the presence of carbonate formations, the elevation and the rate of karst development. In both groups, the carbonate chemistry is diagnostic of the effect of karst development. The supersaturation with respect to calcite indicates CO2 degassing, occurring either inside the aquifer in open conduits, or at the outlet in reservoirs. The undersaturation with respect to calcite shows the existence of fast flow and short residence time conditions inside the aquifer. Interaction between groundwater and surrounding host rocks is believed to be the main process responsible for the observed chemical characteristics of groundwater in the study area.

Krypton-81, Helium-4 and Carbon-14 based estimation of groundwater ages in the Guarani Aquifer System: implications for the He-4 geochronometer

Science.gov (United States)

Aggarwal, P. K.; Chang, H. K.; Gastmans, D.; Sturchio, N. C.; Araguas, L.; Matsumoto, T.; Lu, Z.; Jiang, W.; Yokochi, R.; Mueller, P.

2012-12-01

Characterization of aquifer systems remains a challenge, particularly for large aquifers with limited hydrogeological information. Groundwater age is an important parameter that integrates aquifer recharge and flow dynamics and provides the ability to reliably constrain groundwater models. We have used multiple isotope tracers (C-14, He-4, and Kr-81) to estimate the age of groundwater along a 400-km transect in the north-eastern part of the Guarani Aquifer System (GAS) in Brazil. Carbon-14 measurements were made with an AMS, He-4 by mass-spectrometry, and Kr-81 by atom trap trace analysis (ATTA). Groundwater samples were collected along a groundwater flow path that runs from the outcrop area in the east to the deep confined section in the west, where the aquifer is up to about 1000 m deep. Present groundwater recharge occurs in the outcrop areas, as indicated by the presence of tritium and modern 14C. Carbon-14 activities reach values below detection limit at relatively short distances (a few km) from the outcrop. Abundance of 81Kr (half-life 229 Ka), in samples free of C-14, decreases from 0.81±0.11 (expressed as (81Kr/Kr)sample/(81Kr/Kr)air) in the east to 0.18±0.03 in the western-most sample (estimated age = 566±60 ka). Measured 4He-excess is far above that expected from in-situ production rates in sandstone aquifers and overestimates the age by several orders of magnitude. We used 81Kr ages to calibrate the 4He geochronometer which indicates a basal flux of about 2.8 x10-11 cm3STP He/cm2/a. This flux is lower than most estimates of basal flux in previous studies and will allow a wider use of 4He for groundwater dating and aquifer characterization.

Reduced-Order Model for the Geochemical Impacts of Carbon Dioxide, Brine and Trace Metal Leakage into an Unconfined, Oxidizing Carbonate Aquifer, Version 2.1

Energy Technology Data Exchange (ETDEWEB)

Bacon, Diana H.

2013-03-31

The National Risk Assessment Partnership (NRAP) consists of 5 U.S DOE national laboratories collaborating to develop a framework for predicting the risks associated with carbon sequestration. The approach taken by NRAP is to divide the system into components, including injection target reservoirs, wellbores, natural pathways including faults and fractures, groundwater and the atmosphere. Next, develop a detailed, physics and chemistry-based model of each component. Using the results of the detailed models, develop efficient, simplified models, termed reduced order models (ROM) for each component. Finally, integrate the component ROMs into a system model that calculates risk profiles for the site. This report details the development of the Groundwater Geochemistry ROM for the Edwards Aquifer at PNNL. The Groundwater Geochemistry ROM for the Edwards Aquifer uses a Wellbore Leakage ROM developed at LANL as input. The detailed model, using the STOMP simulator, covers a 5x8 km area of the Edwards Aquifer near San Antonio, Texas. The model includes heterogeneous hydraulic properties, and equilibrium, kinetic and sorption reactions between groundwater, leaked CO2 gas, brine, and the aquifer carbonate and clay minerals. Latin Hypercube sampling was used to generate 1024 samples of input parameters. For each of these input samples, the STOMP simulator was used to predict the flux of CO2 to the atmosphere, and the volume, length and width of the aquifer where pH was less than the MCL standard, and TDS, arsenic, cadmium and lead exceeded MCL standards. In order to decouple the Wellbore Leakage ROM from the Groundwater Geochemistry ROM, the response surface was transformed to replace Wellbore Leakage ROM input parameters with instantaneous and cumulative CO2 and brine leakage rates. The most sensitive parameters proved to be the CO2 and brine leakage rates from the well, with equilibrium coefficients for calcite and dolomite, as well as the number of illite and kaolinite

Ground Water movement in crystalline rock aquifers

International Nuclear Information System (INIS)

Serejo, A.N.C.; Freire, C.; Siqueira, H.B. de; Frischkorn, H.; Torquato, J.R.F.; Santiago, M.M.F.; Barbosa, P.C.

1984-01-01

Ground water movement studies were performed in crystalline rock aquifers from the upper Acarau River hydrographic basin, state of Ceara, Brazil. The studies included carbon-14, 18 O/ 16 O and tritium measurements as well as chemical analysis. A total of 35 wells were surveyed during drought seasons. Carbon-14 values displayed little variation which implied that the water use was adequate despite of the slower recharge conditions. Fairly constant isotopic 18 O/ 16 O ratio values in the wells and their similarity with rainwater values indicated that the recharge is done exclusively by pluvial waters. A decreasing tendency within the tritium concentration values were interpreted as a periodic rainwater renewal for these aquifers. The chemical analysis demonstrated that there is in fact no correlation between salinity and the time the water remains in the aquifer itself. (D.J.M.) [pt

Water-level altitudes 2011 and water-level changes in the Chicot, Evangeline, and Jasper aquifers and compaction 1973-2010 in the Chicot and Evangeline aquifers, Houston-Galveston region, Texas

Science.gov (United States)

Johnson, Michaela R.; Ramage, Jason K.; Kasmarek, Mark C.

2011-01-01

Most of the subsidence in the Houston–Galveston region has occurred as a direct result of groundwater withdrawals for municipal supply, industrial use, and irrigation that depressured and dewatered the Chicot and Evangeline aquifers causing compaction of the clay layers of the aquifer sediments. This report, prepared by the U.S. Geological Survey, in cooperation with the Harris–Galveston Subsidence District, City of Houston, Fort Bend Subsidence District, and Lone Star Groundwater Conservation District, is one in an annual series of reports depicting water-level altitudes and water-level changes in the Chicot, Evangeline, and Jasper aquifers and compaction in the Chicot and Evangeline aquifers in the Houston–Galveston region. The report contains maps showing 2011 water-level altitudes for the Chicot, Evangeline, and Jasper aquifers; maps showing 1-year (2010–11) water-level-altitude changes for each aquifer; maps showing 5-year (2006–11) water-level-altitude changes for each aquifer; maps showing long-term (1990–2011 and 1977–2011) water-level-altitude changes for the Chicot and Evangeline aquifers; a map showing long-term (2000–11) water-level-altitude change for the Jasper aquifer; a map showing locations of borehole extensometer sites; and graphs showing measured compaction of subsurface material at the extensometers from 1973, or later, through 2010. Tables listing the data used to construct each aquifer-data map and the compaction graphs are included.Water levels in the Chicot, Evangeline, and Jasper aquifers were measured during December 2010–February 2011. In 2011, water-level-altitude contours for the Chicot aquifer ranged from 200 feet below North American Vertical Datum of 1988 (hereinafter, datum) in a small area in southwestern Harris County to 200 feet above datum in central to southwestern Montgomery County. Water-level-altitude changes in the Chicot aquifer ranged from a 40-foot decline to a 33-foot rise (2010–11), from a 10-foot

Water-level altitudes 2010 and water-level changes in the Chicot, Evangeline, and Jasper aquifers and compaction 1973-2009 in the Chicot and Evangeline aquifers, Houston-Galveston region, Texas

Science.gov (United States)

Kasmarek, Mark C.; Johnson, Michaela R.; Ramage, Jason K.

2010-01-01

Most of the subsidence in the Houston-Galveston region has occurred as a direct result of groundwater withdrawals for municipal supply, industrial use, and irrigation that depressured and dewatered the Chicot and Evangeline aquifers causing compaction of the clay layers of the aquifer sediments. This report, prepared by the U.S. Geological Survey, in cooperation with the Harris-Galveston Subsidence District, City of Houston, Fort Bend Subsidence District, and Lone Star Groundwater Conservation District, is one in an annual series of reports depicting water-level altitudes and water-level changes in the Chicot, Evangeline, and Jasper aquifers and compaction in the Chicot and Evangeline aquifers in the Houston-Galveston region. The report contains maps showing 2010 water-level altitudes for the Chicot, Evangeline, and Jasper aquifers, respectively; maps showing 1-year (2009-10) water-level-altitude changes for each aquifer; maps showing 5-year (2005-10) water-level-altitude changes for each aquifer; maps showing long-term (1990-2010 and 1977-2010) water-level-altitude changes for the Chicot and Evangeline aquifers; a map showing long-term (2000-10) water-level-altitude change for the Jasper aquifer; a map showing locations of borehole extensometer sites; and graphs showing measured compaction of subsurface material at the extensometers from 1973, or later, through 2009. Tables listing the data used to construct each aquifer-data map and the compaction graphs are included. Water levels in the Chicot, Evangeline, and Jasper aquifers were measured during December 2009-March 2010. In 2010, water-level-altitude contours for the Chicot aquifer ranged from 200 feet below National Geodetic Vertical Datum of 1929 or North American Vertical Datum of 1988 (hereinafter, datum) in a small area in southwestern Harris County to 200 feet above datum in central to southwestern Montgomery County. Water-level-altitude changes in the Chicot aquifer ranged from a 49-foot decline to a 67

Carbon-14 measurements and characterization of dissolved organic carbon in ground water

International Nuclear Information System (INIS)

Murphy, E.M.

1987-01-01

Carbon-14 was measured in the dissolved organic carbon (DOC) in ground water and compared with 14 C analyses of dissolved inorganic carbon (DIC). Two field sites were used for this study; the Stripa mine in central Sweden, and the Milk River Aquifer in southern Alberta, Canada. The Stripa mine consists of a Precambrian granite dominated by fracture flow, while the Milk River Aquifer is a Cretaceous sandstone aquifer characterized by porous flow. At both field sites, 14 C analyses of the DOC provide additional information on the ground-water age. Carbon-14 was measured on both the hydrophobic and hydrophilic organic fractions of the DOC. The organic compounds in the hydrophobic and hydrophilic fractions were also characterized. The DOC may originate from kerogen in the aquifer matrix, from soil organic matter in the recharge zone, of from a combination of these two sources. Carbon-14 analyses, along with characterization of the organics, were used to determine this origin. Carbon-14 analyses of the hydrophobic fraction in the Milk River Aquifer suggest a soil origin, while 14 C analyses of the hydrophilic fraction suggest an origin within the Cretaceous sediments (kerogen) or from the shale in contact with the aquifer

An evaluation of aquifer intercommunication between the unconfined and Rattlesnake Ridge aquifers on the Hanford Site

International Nuclear Information System (INIS)

Jensen, E.J.

1987-10-01

During 1986, Pacific Northwest Laboratory conducted a study of a portion of the Rattlesnake Ridge aquifer (confined aquifer) that lies beneath the B Pond - Gable Mountain Pond area of the Hanford Site. The purpose was to determine the extent of intercommunication between the unconfined aquifer and the uppermost regionally extensive confined aquifer, referred to as the Rattlesnake Ridge aquifer. Hydraulic head data and chemical data were collected from the ground water in the study area during December 1986. The hydraulic head data were used to determine the effects caused by water discharged to the ground from B Pond on both the water table of the unconfined aquifer and the potentiometric surface of the confined aquifer. The chemical data were collected to determine the extent of chemical constituents migrating from the unconfined aquifer to the confined aquifer. Analysis of chemical constituents in the Rattlesnake Ridge aquifer demonstrated that communication between the unconfined and confined aquifers had occurred. However, the levels of contaminants found in the Rattlesnake Ridge aquifer during this study were below the DOE Derived Concentration Guides

Multiple-scale hydraulic characterization of a surficial clayey aquitard overlying a regional aquifer in Louisiana

Science.gov (United States)

Chapman, Steven W.; Cherry, John A.; Parker, Beth L.

2018-03-01

The vertical hydraulic conductivity (Kv) of a 30-m thick surficial clayey aquitard overlying a regional aquifer at an industrial site in the Mississippi River Valley in Louisiana was investigated via intensive hydraulic characterization using high resolution vertical hydraulic head profiles with temporal monitoring and laboratory tests. A study area was instrumented with a semi-circular array of piezometers at many depths in the aquitard at equal distance from a large capacity pumping well including replicate piezometers. Profiles showed negligible head differential to 20 m bgs, below which there was an abrupt change in vertical gradients over the lower 8-10 m of the aquitard. Hydraulic characteristics are strongly associated with depositional environment; the upper zone of minimal head differentials with depth and minimal variation over time correlates with Paleo-Mississippi River backswamp deposits, while the lower zone with large head differentials and slow but moderate head changes correlates with lacustrine deposits. The lower zone restricts groundwater flow between the surface and underlying regional aquifer, which is hydraulically connected to the Mississippi River. Lab tests on lacustrine samples show low Kv (8 × 10-11-4 × 10-9 m/s) bracketing field estimates (6 × 10-10 m/s) from 1-D model fits to piezometric data in response to large aquifer head changes. The slow response indicates absence of through-going open fractures in the lacustrine unit, consistent with geotechnical properties (high plasticity, normal consolidation), suggesting high integrity that protects the underlying aquifer from surficial contamination. The lack of vertical gradients in the overlying backswamp unit indicates abundant secondary permeability features (e.g. fractures, rootholes) consistent with depositional and weathering conditions. 2-D stylized transient flow simulations including both units supports this interpretation. Other published reports on surficial aquitards in the

Pilot Studies of Geologic and Terrestrial Carbon Sequestration in the Big Sky Region, USA, and Opportunities for Commercial Scale Deployment of New Technologies

Science.gov (United States)

Waggoner, L. A.; Capalbo, S. M.; Talbott, J.

2007-05-01

Within the Big Sky region, including Montana, Idaho, South Dakota, Wyoming and the Pacific Northwest, industry is developing new coal-fired power plants using the abundant coal and other fossil-based resources. Of crucial importance to future development programs are robust carbon mitigation plans that include a technical and economic assessment of regional carbon sequestration opportunities. The objective of the Big Sky Carbon Sequestration Partnership (BSCSP) is to promote the development of a regional framework and infrastructure required to validate and deploy carbon sequestration technologies. Initial work compiled sources and potential sinks for carbon dioxide (CO2) in the Big Sky Region and developed the online Carbon Atlas. Current efforts couple geologic and terrestrial field validation tests with market assessments, economic analysis and regulatory and public outreach. The primary geological efforts are in the demonstration of carbon storage in mafic/basalt formations, a geology not yet well characterized but with significant long-term storage potential in the region and other parts of the world; and in the Madison Formation, a large carbonate aquifer in Wyoming and Montana. Terrestrial sequestration relies on management practices and technologies to remove atmospheric CO2 to storage in trees, plants, and soil. This indirect sequestration method can be implemented today and is on the front-line of voluntary, market-based approaches to reduce CO2 emissions. Details of pilot projects are presented including: new technologies, challenges and successes of projects and potential for commercial-scale deployment.

Can Remote Sensing Detect Aquifer Characteristics?: A Case Study in the Guarani Aquifer System

Science.gov (United States)

Richey, A. S.; Thomas, B.; Famiglietti, J. S.

2013-12-01

Global water supply resiliency depends on groundwater, especially regions threatened by population growth and climate change. Aquifer characteristics, even as basic as confined versus unconfined, are necessary to prescribe regulations to sustainably manage groundwater supplies. A significant barrier to sustainable groundwater management exists in the difficulties associated with mapping groundwater resources and characteristics at a large spatial scale. This study addresses this challenge by investigating if remote sensing, including with NASA's Gravity Recovery and Climate Experiment (GRACE), can detect and quantify key aquifer parameters and characteristics. We explore this through a case study in the Guarani Aquifer System (GAS) of South America, validating our remote sensing-based findings against the best available regional estimates. The use of remote sensing to advance the understanding of large aquifers is beneficial to sustainable groundwater management, especially in a trans-boundary system, where consistent information exchange can occur within hydrologic boundaries instead of political boundaries.

14C measurements in aquifers with methane

International Nuclear Information System (INIS)

Barker, J.F.; Fritz, P.; Brown, R.M.

1978-01-01

A survey of various groundwater systems indicates that methane is a common trace constituent and occasionally a major carbon species in groundwaters. Thermocatalytic methane had delta 13 CCH 4 > -45% 0 and microbially-produced or biogenic methane had delta 13 CCH 4 0 . Groundwaters containing significant biogenic methane had abnormally heavy delta 13 C values for the inorganic carbon. Thermocatalytic methane had no apparent effect on the inorganic carbon. Because methanogenesis seriously affects the carbon isotope geochemistry of groundwaters, the correction of raw 14 C ages of affected groundwaters must consider these effects. Conceptual models are developed which adjust the 14 C activity of the groundwater for the effects of methanogenesis and for the dilution of carbon present during infiltration by simple dissolution of rock carbonate. These preliminary models are applied to groundwaters from the Alliston sand aquifer where methanogenesis has affected most samples. In this system, methanogenic bacteria using organic matter present in the aquifer matrix as substrate, have added inorganic carbon to the groundwater which has initiated further carbonate rock dissolution. These processes have diluted the inorganic carbon 14 C activity. (orig.) [de

Ground-water-quality assessment of the Central Oklahoma Aquifer, Oklahoma: geochemical and geohydrologic investigations

Science.gov (United States)

Parkhurst, David L.; Christenson, Scott C.; Breit, George N.

1993-01-01

aquifer, and (3) a deep, regional flow system in the confined part of the aquifer. In the shallow, local flow system, water flows relatively quickly along short flowlines from the point of recharge to the point of discharge at the nearest stream. Many water samples from shallow wells contain large concentrations of tritium, which indicate ground-water ages of less than 40 years. In the deep, regional flow system in the unconfined part of the aquifer, water takes more time to flow along longer flowlines than in the shallow, local flow system. Much of the water in this flow system is recharged along ridges that correspond to ground-water divides between drainage basins. Transit times for water recharging the aquifer along ridges is greater than 5,000 years, computed using a numerical flow model in conjunction with a particle-tracking model. The deep, regional flow system in the confined part of the Garber Sandstone and Wellington Formation is recharged from a small part of the outcrop area of the Garber Sandstone. From the recharge area, water flows west under the confining unit to discharge to streams as far away as the Cimarron River. Flowpaths are relatively long, as much as 50 miles. The transit times in this flow system range from thousands to tens of thousands of years.The long-term hydrogeochemical process occurring in the Central Oklahoma aquifer is removal of unstable minerals, including dolomite, calcite, biotite, chlorite, and feldspars, and the replacement of exchangeable sodium on clays with calcium and magnesium. Over geologic time, the flux of water through the rapidly moving, local flow system has been sufficient to remove most of the dolomite, calcite, and exchangeable sodium. In places, chlorite and feldspars have been removed. In the deep, regional flow system of the unconfined part of the Garber Sandstone and Wellington Formation, the flux of water has been sufficient to remove most of the exchangeable sodium, but carbonate minerals remain sufficiently

Implementation of a 3d numerical model of a folded multilayer carbonate aquifer

Science.gov (United States)

Di Salvo, Cristina; Guyennon, Nicolas; Romano, Emanuele; Bruna Petrangeli, Anna; Preziosi, Elisabetta

2016-04-01

The main objective of this research is to present a case study of the numerical model implementation of a complex carbonate, structurally folded aquifer, with a finite difference, porous equivalent model. The case study aquifer (which extends over 235 km2 in the Apennine chain, Central Italy) provides a long term average of 3.5 m3/s of good quality groundwater to the surface river network, sustaining the minimum vital flow, and it is planned to be exploited in the next years for public water supply. In the downstream part of the river in the study area, a "Site of Community Importance" include the Nera River for its valuable aquatic fauna. However, the possible negative effects of the foreseen exploitation on groundwater dependent ecosystems are a great concern and model grounded scenarios are needed. This multilayer aquifer was conceptualized as five hydrostratigraphic units: three main aquifers (the uppermost unconfined, the central and the deepest partly confined), are separated by two locally discontinuous aquitards. The Nera river cuts through the two upper aquifers and acts as the main natural sink for groundwater. An equivalent porous medium approach was chosen. The complex tectonic structure of the aquifer requires several steps in defining the conceptual model; the presence of strongly dipping layers with very heterogeneous hydraulic conductivity, results in different thicknesses of saturated portions. Aquifers can have both unconfined or confined zones; drying and rewetting must be allowed when considering recharge/discharge cycles. All these characteristics can be included in the conceptual and numerical model; however, being the number of flow and head target scarce, the over-parametrization of the model must be avoided. Following the principle of parsimony, three steady state numerical models were developed, starting from a simple model, and then adding complexity: 2D (single layer), QUASI -3D (with leackage term simulating flow through aquitards) and

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)

Accounting for the Decreasing Reaction Potential of Heterogeneous Aquifers in a Stochastic Framework of Aquifer-Scale Reactive Transport

Science.gov (United States)

Loschko, Matthias; Wöhling, Thomas; Rudolph, David L.; Cirpka, Olaf A.

2018-01-01

Many groundwater contaminants react with components of the aquifer matrix, causing a depletion of the aquifer's reactivity with time. We discuss conceptual simplifications of reactive transport that allow the implementation of a decreasing reaction potential in reactive-transport simulations in chemically and hydraulically heterogeneous aquifers without relying on a fully explicit description. We replace spatial coordinates by travel-times and use the concept of relative reactivity, which represents the reaction-partner supply from the matrix relative to a reference. Microorganisms facilitating the reactions are not explicitly modeled. Solute mixing is neglected. Streamlines, obtained by particle tracking, are discretized in travel-time increments with variable content of reaction partners in the matrix. As exemplary reactive system, we consider aerobic respiration and denitrification with simplified reaction equations: Dissolved oxygen undergoes conditional zero-order decay, nitrate follows first-order decay, which is inhibited in the presence of dissolved oxygen. Both reactions deplete the bioavailable organic carbon of the matrix, which in turn determines the relative reactivity. These simplifications reduce the computational effort, facilitating stochastic simulations of reactive transport on the aquifer scale. In a one-dimensional test case with a more detailed description of the reactions, we derive a potential relationship between the bioavailable organic-carbon content and the relative reactivity. In a three-dimensional steady-state test case, we use the simplified model to calculate the decreasing denitrification potential of an artificial aquifer over 200 years in an ensemble of 200 members. We demonstrate that the uncertainty in predicting the nitrate breakthrough in a heterogeneous aquifer decreases with increasing scale of observation.

An Assessment of Regional Water Resources and Agricultural Sustainability in the Mississippi River Alluvial Aquifer System of Mississippi and Arkansas Under Current and Future Climate

Science.gov (United States)

Rigby, J.; Reba, M.

2011-12-01

The Lower Mississippi River Alluvial Plain is a highly productive agricultural region for rice, soy beans, and cotton that depends heavily on irrigation. Development of the Mississippi River Alluvial Aquifer (MRAA), one of the more prolific agricultural aquifers in the country, has traditionally been the primary source for irrigation in the region yielding over 1,100 Mgal/day to irrigation wells. Increasingly, the realities of changing climate and rapidly declining water tables have highlighted the necessity for new water management practices. Tail-water recovery and reuse is a rapidly expanding practice due in part to the efforts and cost-sharing of the NRCS, but regional studies of the potential for such practices to alleviate groundwater mining under current and future climate are lacking. While regional studies of aquifer geology have long been available, including assessments of regional groundwater flow, much about the aquifer is still not well understood including controls on recharge rates, a crucial component of water management design. We review the trends in regional availability of surface and groundwater resources, their current status, and the effects of recent changes in management practices on groundwater decline in Mississippi and Arkansas. Global and regional climate projections are used to assess scenarios of sustainable aquifer use under current land use and management along with the potential for more widely practiced surface water capture and reuse to alleviate groundwater decline. Finally, we highlight crucial knowledge gaps and challenges associated with the development of water management practices for sustainable agricultural use in the region.

Revised hydrogeologic framework of the Floridan aquifer system in Florida and parts of Georgia, Alabama, and South Carolina

Science.gov (United States)

Williams, Lester J.; Kuniansky, Eve L.

2015-04-08

The hydrogeologic framework for the Floridan aquifer system has been revised throughout its extent in Florida and parts of Georgia, Alabama, and South Carolina. The updated framework generally conforms to the original framework established by the U.S. Geological Survey in the 1980s, except for adjustments made to the internal boundaries of the Upper and Lower Floridan aquifers and the individual higher and contrasting lower permeability zones within these aquifers. The system behaves as one aquifer over much of its extent; although subdivided vertically into two aquifer units, the Upper and Lower Floridan aquifers. In the previous framework, discontinuous numbered middle confining units (MCUI–VII) were used to subdivide the system. In areas where less-permeable rocks do not occur within the middle part of the system, the system was previously considered one aquifer and named the Upper Floridan aquifer. In intervening years, more detailed data have been collected in local areas, resulting in some of the same lithostratigraphic units in the Floridan aquifer system being assigned to the Upper or Lower Floridan aquifer in different parts of the State of Florida. Additionally, some of the numbered middle confining units are found to have hydraulic properties within the same order of magnitude as the aquifers. A new term “composite unit” is introduced for lithostratigraphic units that cannot be defined as either a confining or aquifer unit over their entire extent. This naming convention is a departure from the previous framework, in that stratigraphy is used to consistently subdivide the aquifer system into upper and lower aquifers across the State of Florida. This lithostratigraphic mapping approach does not change the concept of flow within the system. The revised boundaries of the Floridan aquifer system were mapped by considering results from local studies and regional correlations of lithostratigraphic and hydrogeologic units or zones. Additional zones within

A conceptual model of the hydrogeologic framework, geochemistry, and groundwater-flow system of the Edwards-Trinity and related aquifers in the Pecos County region, Texas

Science.gov (United States)

Bumgarner, Johnathan R.; Stanton, Gregory P.; Teeple, Andrew; Thomas, Jonathan V.; Houston, Natalie A.; Payne, Jason; Musgrove, MaryLynn

2012-01-01

A conceptual model of the hydrogeologic framework, geochemistry, and groundwater-flow system of the Edwards-Trinity and related aquifers, which include the Pecos Valley, Igneous, Dockum, Rustler, and Capitan Reef aquifers, was developed as the second phase of a groundwater availability study in the Pecos County region in west Texas. The first phase of the study was to collect and compile groundwater, surface-water, water-quality, geophysical, and geologic data in the area. The third phase of the study involves a numerical groundwater-flow model of the Edwards-Trinity aquifer in order to simulate groundwater conditions based on various groundwater-withdrawal scenarios. Resource managers plan to use the results of the study to establish management strategies for the groundwater system. The hydrogeologic framework is composed of the hydrostratigraphy, structural features, and hydraulic properties of the groundwater system. Well and geophysical logs were interpreted to define the top and base surfaces of the Edwards-Trinity aquifer units. Elevations of the top and base of the Edwards-Trinity aquifer generally decrease from the southwestern part of the study area to the northeast. The thicknesses of the Edwards-Trinity aquifer units were calculated using the interpolated top and base surfaces of the hydrostratigraphic units. Some of the thinnest sections of the aquifer were in the eastern part of the study area and some of the thickest sections were in the Pecos, Monument Draw, and Belding-Coyanosa trough areas. Normal-fault zones, which formed as growth and collapse features as sediments were deposited along the margins of more resistant rocks and as overlying sediments collapsed into the voids created by the dissolution of Permian-age evaporite deposits, were delineated based on the interpretation of hydrostratigraphic cross sections. The lowest aquifer transmissivity values were measured in the eastern part of the study area; the highest transmissivity values were

Guarani aquifer

International Nuclear Information System (INIS)

2007-01-01

The environmental protection and sustain ability develop project of Guarani Aquifer System is a join work from Argentina, Brazil, Paraguay and Uruguay with a purpose to increase the knowledge resource and propose technical legal and organizational framework for sustainable management between countries.The Universities funds were created as regional universities support in promotion, training and academic research activities related to environmental al social aspects of the Guarani Aquifer System.The aim of the project is the management and protection of the underground waters resources taking advantage and assesment for nowadays and future generations

Resistivity method contribution in determining of fault zone and hydro-geophysical characteristics of carbonate aquifer, eastern desert, Egypt

Science.gov (United States)

Ammar, A. I.; Kamal, K. A.

2018-03-01

Determination of fault zone and hydro-geophysical characteristics of the fractured aquifers are complicated, because their fractures are controlled by different factors. Therefore, 60 VESs were carried out as well as 17 productive wells for determining the locations of the fault zones and the characteristics of the carbonate aquifer at the eastern desert, Egypt. The general curve type of the recorded rock units was QKH. These curves were used in delineating the zones of faults according to the application of the new assumptions. The main aquifer was included at end of the K-curve type and front of the H-curve type. The subsurface layers classified into seven different geoelectric layers. The fractured shaly limestone and fractured limestone layers were the main aquifer and their resistivity changed from low to medium (11-93 Ω m). The hydro-geophysical properties of this aquifer such as the areas of very high, high, and intermediate fracture densities of high groundwater accumulations, salinity, shale content, porosity distribution, and recharging and flowing of groundwater were determined. The statistical analysis appeared that depending of aquifer resistivity on the water salinities (T.D.S.) and water resistivities add to the fracture density and shale content. The T.D.S. increasing were controlled by Na+, Cl-, Ca2+, Mg2+, and then (SO4)2-, respectively. The porosity was calculated and its average value was 19%. The hydrochemical analysis of groundwater appeared that its type was brackish and the arrangements of cation concentrations were Na+ > Ca2+ > Mg2+ > K+ and anion concentrations were Cl- > (SO4)2- > HCO3 - > CO3 -. The groundwater was characterized by sodium-bicarbonate and sodium-sulfate genetic water types and meteoric in origin. Hence, it can use the DC-resistivity method in delineating the fault zone and determining the hydro-geophysical characteristics of the fractured aquifer with taking into account the quality of measurements and interpretation.

Estimating Groundwater Mounding in Sloping Aquifers for Managed Aquifer Recharge.

Science.gov (United States)

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

2017-11-01

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

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)

Duvert, Clément; Raiber, Matthias; Owen, Daniel D.R.; Cendón, Dioni I.; Batiot-Guilhe, Christelle; Cox, Malcolm E.

2015-01-01

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–HCO 3 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–HCO 3 –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

Denitrification in a hypersaline lake–aquifer system (Pétrola Basin, Central Spain): The role of recent organic matter and Cretaceous organic rich sediments

International Nuclear Information System (INIS)

Gómez-Alday, J.J.; Carrey, R.; Valiente, N.; Otero, N.; Soler, A.; Ayora, C.; Sanz, D.

2014-01-01

Agricultural regions in semi-arid to arid climates with associated saline wetlands are one of the most vulnerable environments to nitrate pollution. The Pétrola Basin was declared vulnerable to NO 3 − pollution by the Regional Government in 1998, and the hypersaline lake was classified as a heavily modified body of water. The study assessed groundwater NO 3 − through the use of multi-isotopic tracers (δ 15 N, δ 34 S, δ 13 C, δ 18 O) coupled to hydrochemistry in the aquifer connected to the eutrophic lake. Hydrogeologically, the basin shows two main flow components: regional groundwater flow from recharge areas (Zone 1) to the lake (Zone 2), and a density-driven flow from surface water to the underlying aquifer (Zone 3). In Zones 1 and 2, δ 15 N NO 3 and δ 18 O NO 3 suggest that NO 3 − from slightly volatilized ammonium synthetic fertilizers is only partially denitrified. The natural attenuation of NO 3 − can occur by heterotrophic reactions. However, autotrophic reactions cannot be ruled out. In Zone 3, the freshwater–saltwater interface (down to 12–16 m below the ground surface) is a reactive zone for NO 3 − attenuation. Tritium data suggest that the absence of NO 3 − in the deepest zones of the aquifer under the lake can be attributed to a regional groundwater flow with long residence time. In hypersaline lakes the geometry of the density-driven flow can play an important role in the transport of chemical species that can be related to denitrification processes. - Highlights: • Denitrification comes about in a hypersaline lake–aquifer system. • Nitrate in the basin is derived from synthetic fertilizers slightly volatilized. • Organic carbon oxidation is likely to be the main electron donor in denitrification. • Density driven flow transports organic carbon to deeper zones of the aquifer

Variations in hydraulic conductivity with scale of measurement during aquifer tests in heterogeneous, porous carbonate rocks

Science.gov (United States)

Schulze-Makuch, Dirk; Cherkauer, Douglas S.

Previous studies have shown that hydraulic conductivity of an aquifer seems to increase as the portion of the aquifer tested increases. To date, such studies have all relied on different methods to determine hydraulic conductivity at each scale of interest, which raises the possibility that the observed increase in hydraulic conductivity is due to the measurement method, not to the scale. This study analyzes hydraulic conductivity with respect to scale during individual aquifer tests in porous, heterogeneous carbonate rocks in southeastern Wisconsin, USA. Results from this study indicate that hydraulic conductivity generally increases during an individual test as the volume of aquifer impacted increases, and the rate of this increase is the same as the rate of increase determined by using different measurement methods. Thus, scale dependence of hydraulic conductivity during single tests does not depend on the method of measurement. This conclusion is supported by 22 of 26 aquifer tests conducted in porous-flow-dominated carbonate units within the aquifer. Instead, scale dependency is probably caused by heterogeneities within the aquifer, a conclusion supported by digital simulation. All of the observed types of hydraulic-conductivity variations with scale during individual aquifer tests can be explained by a conceptual model of a simple heterogeneous aquifer composed of high-conductivity zones within a low-conductivity matrix. Résumé Certaines études ont montré que la conductivité hydraulique d'un aquifère semble augmenter en même temps que la partie testée de l'aquifère s'étend. Jusqu'à présent, ces études ont toutes reposé sur des méthodes de détermination de la conductivité hydraulique différentes pour chaque niveau d'échelle, ce qui a conduit à penser que l'augmentation observée de la conductivité hydraulique pouvait être due aux méthodes de mesure et non à l'effet d'échelle. Cette étude analyse la conductivité hydraulique par

Application of the finite element groundwater model FEWA to three regional aquifers

International Nuclear Information System (INIS)

Wong, K.F.V.; Yeh, G.T.

1986-06-01

This report documents the calibration with field data and predictive application of a finite element model of water through aquifers (FEWA). FEWA was described in a report written by G.T. Yeh and D.D. Huff in 1983. The model was first compared with the United States Geological Survey (USGS) two-dimensional model and found superior in treating anisotropic media when the coordinates cannot be made to coincide with the principal directions of hydraulic conductivities. In addition, there was no necessity to define nodal points outside the region, as required by the USGS model. FEWA was next calibrated with measured potentiometric surfaces from the Love Canal area in New York and the Conesville area in Ohio. There were satisfactory matches between computed results and available field data. The calibration and predictive runs of FEWA were then accomplished with the Hialeah-Preston well field data over the Biscayne aquifer in south Florida. The calibration run yielded two values of hydraulic conductivity in the area, and the predictive run gave results that matched well with available data. 18 refs., 28 figs

Application of the finite element groundwater model FEWA to three regional aquifers

Energy Technology Data Exchange (ETDEWEB)

Wong, K.F.V.; Yeh, G.T.

1986-06-01

This report documents the calibration with field data and predictive application of a finite element model of water through aquifers (FEWA). FEWA was described in a report written by G.T. Yeh and D.D. Huff in 1983. The model was first compared with the United States Geological Survey (USGS) two-dimensional model and found superior in treating anisotropic media when the coordinates cannot be made to coincide with the principal directions of hydraulic conductivities. In addition, there was no necessity to define nodal points outside the region, as required by the USGS model. FEWA was next calibrated with measured potentiometric surfaces from the Love Canal area in New York and the Conesville area in Ohio. There were satisfactory matches between computed results and available field data. The calibration and predictive runs of FEWA were then accomplished with the Hialeah-Preston well field data over the Biscayne aquifer in south Florida. The calibration run yielded two values of hydraulic conductivity in the area, and the predictive run gave results that matched well with available data. 18 refs., 28 figs.

Rare Earth Element Concentrations and Fractionation Patterns Along Groundwater Flow Paths in Two Different Aquifer Types (i.e., Sand vs. Carbonate)

Science.gov (United States)

Johannesson, K. H.; Tang, J.

2003-12-01

Groundwater samples were collected in two different types of aquifer (i.e., Carrizo Sand Aquifer, Texas and Upper Floridan carbonate Aquifer, west-central Florida) to study the concentrations, fractionation, and speciation of rare earth elements (REE) along groundwater flow paths in each aquifer. Major solutes and dissolved organic carbon (DOC) were also measured in these groundwaters. The Carrizo Sand aquifer was sampled in October 2002 and June 2003, whereas, to date, we have only sampled the Floridan once (i.e., June 2003). The data reveal no significant seasonal differences in major solute and REE concentrations for the Carrizo. In Carrizo sand aquifer, groundwaters from relatively shallow wells (i.e., less than 167 m) in the recharge zone are chiefly Ca-Na-HCO3-Cl type waters. With flow down-gradient the groundwaters shift composition to the Na-HCO3 waters. pH and alkalinity initially decrease with flow away from the recharge zone before increasing again down-gradient. DOC is generally low (0.65 mg/L) along the flow path. REE concentrations are highest in groundwaters from the recharge zone (Nd 40.5 pmol/kg), and decrease substantially with flow down-gradient reaching relatively low and stable values (Nd 4.1-8.6 pmol/kg) roughly 10 km from the recharge zone. Generally, Carrizo groundwaters exhibit HREE-enriched shale-normalized patterns. The HREE enrichments are especially strong for waters from the recharge zone [(Yb/Nd)SN =1.7-5.6], whereas down-gradient (deep) groundwaters have flatter patterns [(Yb/Nd)SN =0.7-2.5]. All groundwaters have slightly positive Eu anomalies (Eu/Eu* 0.09-0.14) and negative Ce anomalies (Ce/Ce* -0.85 - -0.07). In the Upper Floridan Aquifer, Ca, Mg, SO4, and Cl concentrations generally increase along groundwater flow path, whereas pH and alkalinity generally decrease. DOC is higher (0.64 - 2.29 mg/L) than in the Carrizo and initially increases along the flow path and then decreases down-gradient. LREE (Nd) concentrations generally

Integrated and sustainable management of the shared aquifer systems in the Sahel region

International Nuclear Information System (INIS)

Edwerd, Mickel

2012-01-01

It highlights the project Justification, the long term objective, the specific objectives and the project implementation strategy. The countries which participate to this project are the following: Algeria, Benin, Burkina Faso, Cameroon, central African Republic, Chad, Gambia, Guinea-Bissau, Mali, Mauritania, Niger, Nigeria and Senegal. Regarding Aquifer System we have: Chad Basin, Liptako-Gourma Aquifer, Iullemeden Aquifer, Senegalo-Mauritanian Aquifer and Taoudeni/Tanezrouft Basin.

Preliminary study of the physico-chemical and hydrodynamical characteristics of the crystalline basement aquifer of the Ihorombe region (south of Madagascar)

International Nuclear Information System (INIS)

Rakotoaridera, Z.S.

2008-04-01

The hydrochemical, hydrogeological and isotopic data have been used to determine the chemical and hydrodynamical characteristics of crystalline basement aquifer of the Ihorombe region. The study area is located in the District of Ihosy, which is about 600 km in the south of Antananarivo along the national road 7. Two types of aquifer have been found in this area: a phreatic aquifer composed of alterd metamorphic rocks, and a semi confined aquifer, which flows in a fissured and fractured rocks such as gneiss, and leptinites.The ground water mineralization is controlled by HCO 3- , Ca 2+ , Na + , Cl - . The dominant hydrochemical types of water in the study area are calcium and sodium bicarbonate. Some water samples show chloride types. The groundwater mineralization process is especially due to water rock interaction. The ground water is directly recharged by rain water. For the phreatic aquifer, the tritium values have provide a mean resident time less than 50 years, and for the semi confined aquifer, it is approximately above 100 years. [fr

The Contribution of the Future SWOT Mission to Improve Simulations of River Stages and Stream-Aquifer Interactions at Regional Scale

Science.gov (United States)

Saleh, Firas; Filipo, Nicolas; Biancamaria, Sylvain; Habets, Florence; Rodriguez, Enersto; Mognard, Nelly

2013-09-01

The main objective of this study is to provide a realistic simulation of river stage in regional river networks in order to improve the quantification of stream-aquifer exchanges and better assess the associated aquifer responses that are often impacted by the magnitude and the frequency of the river stage fluctuations. This study extends the earlier work to improve the modeling of the Seine basin with a focus on simulating the hydrodynamics behavior of the Bassée alluvial wetland, a 120 km reach of the Seine River valley located south- east of Paris. The Bassée is of major importance for the drinking-water supply of Paris and surroundings, in addition to its particular hydrodynamic behavior due to the presence of a number of gravels. In this context, the understanding of stream-aquifer interactions is required for water quantity and quality preservation. A regional distributed process-based hydro(geo)logical model, Eau-Dyssée, is used. It aims at the integrated modeling of the hydrosystem to manage the various elements involved in the quantitative and qualitative aspects of water resources. Eau-Dyssée simulates pseudo 3D flow in aquifer systems solving the diffusivity equation with a finite difference numerical scheme. River flow is simulated with a Muskingum model. In addition to the in-stream discharge, a river stage estimate is needed to calculate the water exchange at the stream-aquifer interface using a conductance model. In this context, the future SWOT mission and its high-spatial resolution imagery can provide surface water level measurements at the regional scale that will permit to better characterize the Bassée complex hydro(geo)logical system and better assess soil water content. Moreover, the Bassée is considered as a potential target for the framework of the AirSWOT airborne campaign in France, 2013.

Effects of Land-Use Change and Managed Aquifer Recharge on Geochemical Reactions with Implications for Groundwater Quantity and Quality in Atoll Island Aquifers, Roi-Namur, Republic of the Marshall Islands

Science.gov (United States)

Hejazian, M.; Swarzenski, P. W.; Gurdak, J. J.; Odigie, K. O.; Storlazzi, C. D.

2015-12-01

This study compares the hydrogeochemistry of two contrasting atoll groundwater systems in Roi-Namur, Republic of the Marshall Islands. Roi-Namur houses a U.S. Department of Defense military installation and presents an ideal study location where a human impacted aquifer is co-located next to a natural aquifer as part of two artificially conjoined atoll islands. The hydrogeology and geochemistry of carbonate atoll aquifers has been well studied, particularly because of its small, well-defined hydrologic system that allows for relatively precise modeling. However, it is unknown how changes in land-use/land cover and managed aquifer recharge (MAR) alters natural geochemical processes in atoll aquifers. A better understanding of this has implications on groundwater quantity and quality, carbonate dissolution, and best aquifer management practices in the context of rising sea level and saltwater intrusion. Roi has been heavily modified to house military and civilian operations; here, lack of vegetation and managed recharge has increased the volume of potable groundwater and affected the geochemical processes in the freshwater lens and saltwater transition zone. Namur is heavily vegetated and the hydrogeology is indicative of a natural atoll island. A suite of monitoring wells were sampled across both island settings for major ions, nutrients, trace elements, DOC/DIC, δ13C and δ18O/2H isotopes. By modeling geochemical reactions using a conservative mixing approach, we measure deviations from expected reactions and compare the two contrasting settings using derived geochemical profiles through a wide salinity spectrum. Results indicate that groundwater on Namur is more heavily depleted in δ13C and has greater dissolved inorganic carbon, suggesting higher microbial oxidation and greater dissolution within the carbonate aquifer. This suggests MAR and reduction of vegetation makes the groundwater supply on atoll islands more resilient to sea level rise.

Trench infiltration for managed aquifer recharge to permeable bedrock

Science.gov (United States)

Heilweil, V.M.; Watt, D.E.

2011-01-01

Managed aquifer recharge to permeable bedrock is increasingly being utilized to enhance resources and maintain sustainable groundwater development practices. One such target is the Navajo Sandstone, an extensive regional aquifer located throughout the Colorado Plateau of the western United States. Spreading-basin and bank-filtration projects along the sandstone outcrop's western edge in southwestern Utah have recently been implemented to meet growth-related water demands. This paper reports on a new cost-effective surface-infiltration technique utilizing trenches for enhancing managed aquifer recharge to permeable bedrock. A 48-day infiltration trench experiment on outcropping Navajo Sandstone was conducted to evaluate this alternative surface-spreading artificial recharge method. Final infiltration rates through the bottom of the trench were about 0.5 m/day. These infiltration rates were an order of magnitude higher than rates from a previous surface-spreading experiment at the same site. The higher rates were likely caused by a combination of factors including the removal of lower permeability soil and surficial caliche deposits, access to open vertical sandstone fractures, a reduction in physical clogging associated with silt and biofilm layers, minimizing viscosity effects by maintaining isothermal conditions, minimizing chemical clogging caused by carbonate mineral precipitation associated with algal photosynthesis, and diminished gas clogging associated with trapped air and biogenic gases. This pilot study illustrates the viability of trench infiltration for enhancing surface spreading of managed aquifer recharge to permeable bedrock. ?? 2010.

A Regional Strategy for the Assessment and Management of Transboundary Aquifer Systems in the Americas

Science.gov (United States)

Hanson, R. T.; Rivera, A.; Tujchneider, O.; Guillén, C.; Campos, M.; Da Franca, N.; May, Z.; Aureli, A.

2015-12-01

The UNESCO-IHP ISARM-Americas technical committee has developed a regional strategy for the assessment and management of transboundary aquifer systems in the Americas as part of their ongoing cooperative assistance to help neighboring countries sustain water resources and reduce potential conflict. The fourth book in the series of publications sponsored by UNESCO and OAS documents this strategy. The goal of this strategy is the collective understanding, developing, managing, and protecting of the transboundary aquifers in the Americas This strategy includes technical, social, and governance recommendations for an integrated resource management of groundwater based on flexible arrangements that not only manage but also demand social participation in solving problems, consider changes in land use and water use and promote the increase of water sustainability for all transboundary neighbors. The successful implementation of this strategy starts with sharing information of the status and use of land and water as well as intergovernmental partnerships to link science and policy with existing instruments for managing the water resources. International organizations such as UNESCO and OAS also can help facilitate the development of transboundary agreements and establish cooperation on transboundary aquifers between neighbors. The UNESCO-IHP ISARM-Americas technical committee has been successful in creating a network of partners from 24 countries and in translating existing aquifer knowledge into a meaningful strategy for the American hemisphere. The strategy aims to explain and develop the role of science and the informed-decision approach. Examples from North and South America show how the process has begun to develop for selected transboundary aquifers. These include the Milk River basin between the US and Canada, the Rio Grande and Colorado River basins between the US and Mexico, and the Guarani River basin in South America.

Behaviour and fate of nine recycled water trace organics during managed aquifer recharge in an aerobic aquifer

Science.gov (United States)

Patterson, B. M.; Shackleton, M.; Furness, A. J.; Bekele, E.; Pearce, J.; Linge, K. L.; Busetti, F.; Spadek, T.; Toze, S.

2011-03-01

The fate of nine trace organic compounds was evaluated during a 12 month large-scale laboratory column experiment. The columns were packed with aquifer sediment and evaluated under natural aerobic and artificial anaerobic geochemical conditions, to assess the potential for natural attenuation of these compounds during aquifer passage associated with managed aquifer recharge (MAR). The nine trace organic compounds were bisphenol A (BPA), 17β-estradiol (E2), 17α-ethynylestradiol (EE2), N-nitrosodimethylamine (NDMA), N-nitrosomorpholine (NMOR), carbamazepine, oxazepam, iohexol and iodipamide. In the low organic carbon content Spearwood sediment, all trace organics were non-retarded with retardation coefficients between 1.0 and 1.2, indicating that these compounds would travel at near groundwater velocities within the aquifer. The natural aerobic geochemical conditions provided a suitable environment for the rapid degradation for BPA, E2, iohexol (half life NDMA and NMOR) did not degrade under either aerobic or anaerobic aquifer geochemical conditions (half life > 50 days). Field-based validation experiments with carbamazepine and oxazepam also showed no degradation. If persistent trace organics are present in recycled waters at concentrations in excess of their intended use, natural attenuation during aquifer passage alone may not result in extracted water meeting regulatory requirements. Additional pre treatment of the recycled water would therefore be required.

Behaviour and fate of nine recycled water trace organics during managed aquifer recharge in an aerobic aquifer.

Science.gov (United States)

Patterson, B M; Shackleton, M; Furness, A J; Bekele, E; Pearce, J; Linge, K L; Busetti, F; Spadek, T; Toze, S

2011-03-25

The fate of nine trace organic compounds was evaluated during a 12month large-scale laboratory column experiment. The columns were packed with aquifer sediment and evaluated under natural aerobic and artificial anaerobic geochemical conditions, to assess the potential for natural attenuation of these compounds during aquifer passage associated with managed aquifer recharge (MAR). The nine trace organic compounds were bisphenol A (BPA), 17β-estradiol (E2), 17α-ethynylestradiol (EE2), N-nitrosodimethylamine (NDMA), N-nitrosomorpholine (NMOR), carbamazepine, oxazepam, iohexol and iodipamide. In the low organic carbon content Spearwood sediment, all trace organics were non-retarded with retardation coefficients between 1.0 and 1.2, indicating that these compounds would travel at near groundwater velocities within the aquifer. The natural aerobic geochemical conditions provided a suitable environment for the rapid degradation for BPA, E2, iohexol (half life aquifer geochemical conditions (half life >50days). Field-based validation experiments with carbamazepine and oxazepam also showed no degradation. If persistent trace organics are present in recycled waters at concentrations in excess of their intended use, natural attenuation during aquifer passage alone may not result in extracted water meeting regulatory requirements. Additional pre treatment of the recycled water would therefore be required. Crown Copyright © 2010. Published by Elsevier B.V. All rights reserved.

Soft computing and hydrogeologic characterization of the Serra Geral-Guarani aquifer system, Parana state, Brazil

Science.gov (United States)

Iwashita, F.; Friedel, M. J.; Ferreira, F. J.; Fraser, S. J.

2011-12-01

The Self-organizing map (SOM) technique is used to estimate missing hydrogeologic (hydraulic and hydrochemical) properties and evaluate potential connectivity between the Serra Geral and Guarani aquifer system. K-means clustering of SOM neurons is useful for identifying hydrogeologic units (conceptual models) in which the Serra Geral waters are carbonate-calcium and carbonate-magnesium, and Guarani waters are sodium, chloride, fluoride and sulfate as characteristic elements. SOM predictions appear generally consistent with current connectivity models with vertical fluxes from Guarani aquifer strongly influenced by geological structures. Additionally, we identify other new hydrochemical facies in the Serra Geral aquifer indicating areas with potential connections between the two aquifers.

Water quality requirements for sustaining aquifer storage and recovery operations in a low permeability fractured rock aquifer.

Science.gov (United States)

Page, Declan; Miotliński, Konrad; Dillon, Peter; Taylor, Russel; Wakelin, Steve; Levett, Kerry; Barry, Karen; Pavelic, Paul

2011-10-01

A changing climate and increasing urbanisation has driven interest in the use of aquifer storage and recovery (ASR) schemes as an environmental management tool to supplement conventional water resources. This study focuses on ASR with stormwater in a low permeability fractured rock aquifer and the selection of water treatment methods to prevent well clogging. In this study two different injection and recovery phases were trialed. In the first phase ~1380 m(3) of potable water was injected and recovered over four cycles. In the second phase ~3300 m(3) of treated stormwater was injected and ~2410 m(3) were subsequently recovered over three cycles. Due to the success of the potable water injection cycles, its water quality was used to set pre-treatment targets for harvested urban stormwater of ≤ 0.6 NTU turbidity, ≤ 1.7 mg/L dissolved organic carbon and ≤ 0.2 mg/L biodegradable dissolved organic carbon. A range of potential ASR pre-treatment options were subsequently evaluated resulting in the adoption of an ultrafiltration/granular activated carbon system to remove suspended solids and nutrients which cause physical and biological clogging. ASR cycle testing with potable water and treated stormwater demonstrated that urban stormwater containing variable turbidity (mean 5.5 NTU) and organic carbon (mean 8.3 mg/L) concentrations before treatment could be injected into a low transmissivity fractured rock aquifer and recovered for irrigation supplies. A small decline in permeability of the formation in the vicinity of the injection well was apparent even with high quality water that met turbidity and DOC but could not consistently achieve the BDOC criteria. Copyright © 2011 Elsevier Ltd. All rights reserved.

Demonstrating managed aquifer recharge as a solution for climate change adaptation: results from Gabardine project and asemwaterNet coordination action in the Algarve region (Portugal

Directory of Open Access Journals (Sweden)

João Paulo Lobo Ferreira

2014-09-01

Full Text Available In the Algarve southern Portugal region, Managed Aquifer Recharge (MAR research activities have been developed to provide not only water surplus storage in aquifers during wet years, focusing in the Querença-Silves aquifer (FP6 ASEMWATERNet Coordination Action, but also groundwater quality rehabilitation in the Campina de Faro aquifer (FP6 Gabardine Project. Following MAR research potentialities in southern Portugal, this paper describes the objectives, conceptual demonstration, background and capabilities of one of the selected Circum-Mediterranean pilot sites (in Portugal that will be researched in the new FP7-ENV-2013-WATER-INNO-DEMO MARSOL project, which started Dec. 1st, 2013. In the Algarve pilot site, several case-study areas will be located in the Querença-Silves aquifer and in the Campina de Faro aquifer.

Conceptual and numerical modeling approach of the Guarani Aquifer System

Science.gov (United States)

Rodríguez, L.; Vives, L.; Gomez, A.

2013-01-01

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 the aquifer boundaries, except at the eastern boundary. On average

A conceptual hydrogeologic model for the hydrogeologic framework, geochemistry, and groundwater-flow system of the Edwards-Trinity and related aquifers in the Pecos County region, Texas

Science.gov (United States)

Thomas, Jonathan V.; Stanton, Gregory P.; Bumgarner, Johnathan R.; Pearson, Daniel K.; Teeple, Andrew; Houston, Natalie A.; Payne, Jason; Musgrove, MaryLynn

2013-01-01

The Edwards-Trinity aquifer is a vital groundwater resource for agricultural, industrial, and municipal uses in the Trans-Pecos region of west Texas. A conceptual model of the hydrogeologic framework, geochemistry, and groundwater-flow system in the 4,700 square-mile study area was developed by the U.S. Geological Survey (USGS) in cooperation with the Middle Pecos Groundwater Conservation District, Pecos County, City of Fort Stockton, Brewster County, and Pecos County Water Control and Improvement District No. 1. The model was developed to gain a better understanding of the groundwater system and to establish a scientific foundation for resource-management decisions. Data and information were collected or obtained from various sources to develop the model. Lithologic information obtained from well reports and geophysical data were used to describe the hydrostratigraphy and structural features of the groundwater system, and aquifer-test data were used to estimate aquifer hydraulic properties. Groundwater-quality data were used to evaluate groundwater-flow paths, water and rock interaction, aquifer interaction, and the mixing of water from different sources. Groundwater-level data also were used to evaluate aquifer interaction as well as to develop a potentiometric-surface map, delineate regional groundwater divides, and describe regional groundwater-flow paths.

Stressed aquifers in the Lower Segura basin and the Vinalopó basin in Easter Spain

Directory of Open Access Journals (Sweden)

Andrés Sahuquillo

2016-01-01

Full Text Available The carbonate aquifers of the Lower Segura Basin and the Vinalopó basin, along with some other granular aquifers are being exploited well above its average recharge for almost half a century. That causes a continuous decline of groundwater levels in most of the region, up to 5m/year in some cases and more than 300m from their initial situation in some areas, thus increasing the cost of groundwater pumping. The drop in levels produced the drying of springs and wetlands and increased salinity in some areas caused by the presence of saline formations. Against these problems is the increase in wealth created by the availability of water since the beginning of the intense exploitation of aquifers. The Water Framework Directive requires that aquifers being by 2015 in good quantitative and qualitative conditions, which is not possible, and neither would be delaying this date several decades. Simple analyses indicate that even eliminating pumping; groundwater would take between 100 and 1000years to recover. Several methods have been used for determining groundwater recharge and mathematical models that reproduce aquifer’s behaviour and could be used as valid tools for its management. The role that aquifers can play in the water resource management is discussed.

Water-level altitudes 2016 and water-level changes in the Chicot, Evangeline, and Jasper aquifers and compaction 1973–2015 in the Chicot and Evangeline aquifers, Houston-Galveston region, Texas

Science.gov (United States)

Kasmarek, Mark C.; Ramage, Jason K.; Johnson, Michaela R.

2016-10-07

Most of the land-surface subsidence in the Houston-Galveston region, Texas, has occurred as a direct result of groundwater withdrawals for municipal supply, commercial and industrial use, and irrigation that depressured and dewatered the Chicot and Evangeline aquifers, thereby causing compaction of the aquifer sediments, mostly in the fine-grained silt and clay layers. This report, prepared by the U.S. Geological Survey 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, is one in an annual series of reports depicting water-level altitudes and water-level changes in the Chicot, Evangeline, and Jasper aquifers and measured cumulative compaction of subsurface sediments in the Chicot and Evangeline aquifers in the Houston-Galveston region. The report contains regional-scale maps depicting approximate 2016 water-level altitudes (represented by measurements made during December 2015–March 2016) for the Chicot, Evangeline, and Jasper aquifers; maps depicting 1-year (2015–16) water-level changes for each aquifer; maps depicting approximate contoured 5-year (2011–16) water-level changes for each aquifer; maps depicting approximate contoured long-term (1990–2016 and 1977–2016) water-level changes for the Chicot and Evangeline aquifers; a map depicting approximate contoured long-term (2000–16) water-level changes for the Jasper aquifer; a map depicting locations of borehole-extensometer sites; and graphs depicting measured long-term cumulative compaction of subsurface sediments at the extensometers during 1973–2015. Tables listing the water-level data used to construct each water-level map for each aquifer and the measured long-term cumulative compaction data for each extensometer site are included. Graphs depicting water-level measurement data also are included; these graphs can be used to approximate

Radiocarbon dating of dissolved inorganic carbon in groundwater from confined parts of the Upper Floridan aquifer, Florida, USA

Science.gov (United States)

Plummer, Niel; Sprinkle, Craig

2001-03-01

Geochemical reaction models were evaluated to improve radiocarbon dating of dissolved inorganic carbon (DIC) in groundwater from confined parts of the Upper Floridan aquifer in central and northeastern Florida, USA. The predominant geochemical reactions affecting the 14C activity of DIC include (1) dissolution of dolomite and anhydrite with calcite precipitation (dedolomitization), (2) sulfate reduction accompanying microbial degradation of organic carbon, (3) recrystallization of calcite (isotopic exchange), and (4) mixing of fresh water with as much as 7% saline water in some coastal areas. The calculated cumulative net mineral transfers are negligibly small in upgradient parts of the aquifer and increase significantly in downgradient parts of the aquifer, reflecting, at least in part, upward leakage from the Lower Floridan aquifer and circulation that contacted middle confining units in the Floridan aquifer system. The adjusted radiocarbon ages are independent of flow path and represent travel times of water from the recharge area to the sample point in the aquifer. Downgradient from Polk City (adjusted age 1.7 ka) and Keystone Heights (adjusted age 0.4 ka), 14 of the 22 waters have adjusted 14C ages of 20-30 ka, indicating that most of the fresh-water resource in the Upper Floridan aquifer today was recharged during the last glacial period. All of the paleowaters are enriched in 18O and 2H relative to modern infiltration, with maximum enrichment in δ18O of approximately 2.0‰. Résumé. Les modèles de réactions géochimiques ont été évalués afin de tester la datation par le radiocarbone du carbone minéral dissous (CMD) des eaux souterraines dans les parties captives de la nappe supérieure de Floride, en Floride centrale et nord-orientale (États-Unis). Les réactions géochimiques prédominantes affectant l'activité en 14C du CMD comprennent (1) la dissolution de la dolomite et de l'anhydrite accompagnée de la précipitation de la calcite (d

Denitrification in a hypersaline lake–aquifer system (Pétrola Basin, Central Spain): The role of recent organic matter and Cretaceous organic rich sediments

Energy Technology Data Exchange (ETDEWEB)

Gómez-Alday, J.J., E-mail: JuanJose.Gomez@uclm.es [Hydrogeology Group, Institute for Regional Development (IDR), University of Castilla–La Mancha (UCLM), Campus Universitario s/n, 02071 Albacete (Spain); Carrey, R., E-mail: raulcarrey@ub.edu [Grup d’Mineralogia Aplicada i Medi Ambient, Dep. Cristallografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona, C/ Martí i Franquès s/n, 08028, Barcelona (Spain); Valiente, N., E-mail: Nicolas.Valiente@uclm.es [Hydrogeology Group, Institute for Regional Development (IDR), University of Castilla–La Mancha (UCLM), Campus Universitario s/n, 02071 Albacete (Spain); Otero, N., E-mail: notero@ub.edu [Grup d’Mineralogia Aplicada i Medi Ambient, Dep. Cristallografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona, C/ Martí i Franquès s/n, 08028, Barcelona (Spain); Soler, A., E-mail: albertsolergil@ub.edu [Grup d’Mineralogia Aplicada i Medi Ambient, Dep. Cristallografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona, C/ Martí i Franquès s/n, 08028, Barcelona (Spain); Ayora, C., E-mail: cayora1@gmail.com [Grup d' Hidrologia Subterrània (GHS), Institut de Diagnóstic Ambiental i Estudis de l' Aigua (IDAEA-CSIC), C/Jordi Girona 18, 08028 Barcelona (Spain); Sanz, D. [Hydrogeology Group, Institute for Regional Development (IDR), University of Castilla–La Mancha (UCLM), Campus Universitario s/n, 02071 Albacete (Spain); and others

2014-11-01

Agricultural regions in semi-arid to arid climates with associated saline wetlands are one of the most vulnerable environments to nitrate pollution. The Pétrola Basin was declared vulnerable to NO{sub 3}{sup −} pollution by the Regional Government in 1998, and the hypersaline lake was classified as a heavily modified body of water. The study assessed groundwater NO{sub 3}{sup −} through the use of multi-isotopic tracers (δ{sup 15}N, δ{sup 34}S, δ{sup 13}C, δ{sup 18}O) coupled to hydrochemistry in the aquifer connected to the eutrophic lake. Hydrogeologically, the basin shows two main flow components: regional groundwater flow from recharge areas (Zone 1) to the lake (Zone 2), and a density-driven flow from surface water to the underlying aquifer (Zone 3). In Zones 1 and 2, δ{sup 15}N{sub NO{sub 3}} and δ{sup 18}O{sub NO{sub 3}} suggest that NO{sub 3}{sup −} from slightly volatilized ammonium synthetic fertilizers is only partially denitrified. The natural attenuation of NO{sub 3}{sup −} can occur by heterotrophic reactions. However, autotrophic reactions cannot be ruled out. In Zone 3, the freshwater–saltwater interface (down to 12–16 m below the ground surface) is a reactive zone for NO{sub 3}{sup −} attenuation. Tritium data suggest that the absence of NO{sub 3}{sup −} in the deepest zones of the aquifer under the lake can be attributed to a regional groundwater flow with long residence time. In hypersaline lakes the geometry of the density-driven flow can play an important role in the transport of chemical species that can be related to denitrification processes. - Highlights: • Denitrification comes about in a hypersaline lake–aquifer system. • Nitrate in the basin is derived from synthetic fertilizers slightly volatilized. • Organic carbon oxidation is likely to be the main electron donor in denitrification. • Density driven flow transports organic carbon to deeper zones of the aquifer.

Environmental isotope studies related to groundwater flow and saline encroachment in the chalk aquifer of Lincolnshire, England

International Nuclear Information System (INIS)

Lloyd, J.W.; Howard, K.W.F.

1978-01-01

The isotopes of tritium and carbon are used to study part of the North Lincolnshire Chalk aquifer in England. The tritium data support the view that the aquifer is a thin fissure system and indicate that some changes in flow direction have occurred due to recent abstraction. The data are also consistent with other chemical data in elucidating groundwater entering the Chalk from deeper aquifers. Carbon isotopes are used to distinguish between saline water bodies and suggest that saline water was entrapped within the aquifer in the Eemian and Flandrian stages of the Pleistocene. (orig.) [de

Identifying and quantifying geochemical and mixing processes in the Matanza-Riachuelo Aquifer System, Argentina.

Science.gov (United States)

Armengol, S; Manzano, M; Bea, S A; Martínez, S

2017-12-01

The Matanza-Riachuelo River Basin, in the Northeast of the Buenos Aires Province, is one of the most industrialized and populated region in Argentina and it is worldwide known for its alarming environmental degradation. In order to prevent further damages, the aquifer system, which consists of two overlaid aquifers, is being monitored from 2008 by the river basin authority, Autoridad de la Cuenca Matanza-Riachuelo. The groundwater chemical baseline has been established in a previous paper (Zabala et al., 2016), and this one is devoted to the identification of the main physical and hydrogeochemical processes that control groundwater chemistry and its areal distribution. Thirty five representative groundwater samples from the Upper Aquifer and thirty four from the deep Puelche Aquifer have been studied with a multi-tool approach to understand the origin of their chemical and isotopic values. The resulting conceptual model has been validated though hydrogeochemical modeling. Most of the aquifer system has fresh groundwater, but some areas have brackish and salt groundwater. Water recharging the Upper Aquifer is of the Ca-HCO 3 type as a result of soil CO 2 and carbonate dissolution. Evapotranspiration plays a great role concentrating recharge water. After recharge, groundwater becomes Na-HCO 3 , mostly due to cation exchange with Na release and Ca uptake, which induces calcite dissolution. Saline groundwaters exist in the lower and upper sectors of the basin as a result of Na-HCO 3 water mixing with marine water of different origins. In the upper reaches, besides mixing with connate sea water other sources of SO 4 exist, most probably gypsum and/or sulfides. This work highlights the relevance of performing detailed studies to understand the processes controlling groundwater chemistry at regional scale. Moreover, it is a step forward in the knowledge of the aquifer system, and provides a sound scientific basis to design effective management programs and recovery plans

The use of carbon isotopes in the study of groundwater of the Bambui calcareous-central region of Bahia (Brazil)

International Nuclear Information System (INIS)

Cabral, F.C.F.

1978-06-01

Groundwater of 34 wells and of a spring of the Bambui limestone aquifer, in central Bahia, Brazil, were analized for the 14 C and 13 C content. One sample of soil CO 2 and four of soil organic matter were analized for 13 C. From these data were calculated the 14 C ages of these waters. A major difficulty in the use of radiocarbon in groundwater hydrology is the estimation of the initial 14 C concentration. In many cases, this can be simply determined by the fraction of carbon derived from soil gas, relative to the total carbon dissolved, by the use of Δ 13 C of the soil organic matter, limestone and dissolved carbon in water. This approach does not seem to be completely valid in arid ou semi-arid regions, specially where the pH of the soil is relatively high. In this case, the isotopic composition of the soil water can be determined if the pCO 2 and pH of the soil can be estimated and if the isotopic composition of the soil CO 2 can be known. The final isotopic composition of the groundwater is a combination of the isotopic composition of the soil water and any limestone thereafter dissolved. The 14 C ages of the water samples analized ranged from modern to about 13000 years. The recharge areas of the aquifer are clearly indicated, as the probable underground flow directions. The interpretation of the radiocarbon data is in accord with the hydrologic data. (Author) [pt

In situ aquifer bioremediation of organics including cyanide and carbon disulfide

International Nuclear Information System (INIS)

Abou-Rizk, J.A.M.; Leavitt, M.E.; Graves, D.A.

1995-01-01

Low levels (< 1 mg/L) of acetone, cyanide, phenol, naphthalene, 2-methylnaphthalene, and carbon disulfide from an inactive industrial landfill were found above background levels in a shallow aquifer at an eastern coastal site. In situ biodegradation was evaluated for treatment of these contaminants. Two soil samples and three groundwater samples were taken from the site for a laboratory bioassessment and a biotreatability test. The positive results of the bioassessment suggested moving forward with biotreatability testing. Biotreatability test results indicated suitable site conditions for bioremediation and that all the contaminants of concern at the site could be biodegraded to nondetect or very low levels (< 50 microg/L) with oxygen only; i.e., addition of nutrients was not required. Pilot-scale testing was undertaken on site to provide information for full-scale design, including oxygen requirements and air injection well spacing. This report describes the approach, the results, and their impact on the full-scale remediation system

Charaterising water-rock interaction in a mixed carbonate-evaporite karstified aquifer system, Qatar

Science.gov (United States)

Thirathititham, R.; Whitaker, F.

2017-12-01

Qatar is an arid country, most of the rainfall (80 mm/yr) occurring during intense storms. Surface runoff is endorheic and recharge is facilitated by karst features developed over an extended (c.30 Ma) period of exposure of the carbonate bedrock. In December 2016, we sampled a rare intense rainfall event (41 mm over 3 days), after which waters ponded within low-relief terminal depressions prior to infiltration. We compare the chemistry of these recharge waters with that of ground waters from 76 wells distributed across Qatar to understand the nature and spatial distribution of water-rock interaction. Using Cl- as a conservative tracer for seawater mixing, we calculate concentrations of rock-derived Ca2+, Mg2+ and SO42-. During surface detention, rain chemistry is modified by evaporation and interaction with clays and the surface bedrock over days to weeks. However, groundwater chemistry is dominated by subsurface interaction between recharge waters and the karstified Tertiary aquifers. These include the largely dolomitic Paleocene to Lower Eocene Umm er Radhuma (UER) and overlying Lower Eocene Rus, with the Middle Eocene Abarug limestone forming a locally important aquifer in the south west. Away from coastal areas which show clear evidence of salinisation, TDS of groundwaters in the interior of the peninsula increases from north to south. All groundwaters are significantly enriched in SO42-, but this enrichment is marked greater in the south. This likely reflects the presence of a unit of middle Rus gypsum that in the south of the country confines the Lower Rus and UER aquifers, whilst in the north either gypsum was not deposited or has been dissolved. Waters in the Abarug limestone show limited sulfate enrichment and a 1:1 molar ratio of rock-derived SO42-: Ca2+, but across much of the country both SO42- enrichment and SO42-: Ca2+ molar ratio are significantly higher, the latter reaching 2:1 and suggesting an additional sink for Ca2+. The dolomite aquifer waters

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

2014-09-01

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 (aquifers (nitrate, atrazine, deethylatrazine, tetrachloroethene, and chloroform). Specific consideration of water-quality protection efforts, well construction and placement, and aquifer response times to land-use changes and contaminant loading are discussed, with implications for karst groundwater management. © 2014 The Authors. Groundwater published by Wiley Periodicals, Inc. on behalf of National Ground Water Association.

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.

Contamination risk and drinking water protection for a large-scale managed aquifer recharge site in a semi-arid karst region, Jordan

Science.gov (United States)

Xanke, Julian; Liesch, Tanja; Goeppert, Nadine; Klinger, Jochen; Gassen, Niklas; Goldscheider, Nico

2017-09-01

Karst aquifers in semi-arid regions are particularly threatened by surface contamination, especially during winter seasons when extremely variable rainfall of high intensities prevails. An additional challenge is posed when managed recharge of storm water is applied, since karst aquifers display a high spatial variability of hydraulic properties. In these cases, adapted protection concepts are required to address the interaction of surface water and groundwater. In this study a combined protection approach for the surface catchment of the managed aquifer recharge site at the Wala reservoir in Jordan and the downstream Hidan wellfield, which are both subject to frequent bacteriological contamination, is developed. The variability of groundwater quality was evaluated by correlating contamination events to rainfall, and to recharge from the reservoir. Both trigger increased wadi flow downstream of the reservoir by surface runoff generation and groundwater seepage, respectively. A tracer test verified the major pathway of the surface flow into the underground by infiltrating from pools along Wadi Wala. An intrinsic karst vulnerability and risk map was adapted to the regional characteristics and developed to account for the catchment separation by the Wala Dam and the interaction of surface water and groundwater. Implementation of the proposed protection zones for the wellfield and the reservoir is highly recommended, since the results suggest an extreme contamination risk resulting from livestock farming, arable agriculture and human occupation along the wadi. The applied methods can be transferred to other managed aquifer recharge sites in similar karstic environments of semi-arid regions.

Assessing aquifer storage and recovery feasibility in the Gulf Coastal Plains of Texas

Directory of Open Access Journals (Sweden)

W. Benjamin Smith

2017-12-01

Full Text Available Study region: The Gulf Coast and Carrizo-Wilcox aquifer systems in the Gulf Coastal Plains of Texas. Study focus: Aquifer storage and recovery is a water storage alternative that is underutilized in Texas, a state with both long periods of drought and high intensity storms. Future water storage plans in Texas almost exclusively rely on surface reservoirs, subject to high evaporative losses. This study seeks to identify sites where aquifer storage and recovery (ASR may be successful, especially in recovery of injected waters, by analyzing publicly-available hydrogeologic data. Transmissivity, hydraulic gradient, well density, depth to aquifer, and depth to groundwater are used in a GIS-based index to determine feasibility of implementing an ASR system in the Gulf Coast and Carrizo-Wilcox aquifer systems. New hydrological insights for the region: Large regions of the central and northern Gulf Coast and the central and southern Carrizo-Wilcox aquifer systems are expected to be hydrologically feasible regions for ASR. Corpus Christi, Victoria, San Antonio, Bryan, and College Station are identified as possible cities where ASR would be a useful water storage strategy. Keywords: Aquifer storage and recovery (ASR, GIS, Gulf coast, Carrizo-Wilcox, Managed aquifer recharge (MAR

Geochemistry and origins of mineralized waters in the Floridan aquifer system, northeastern Florida

Science.gov (United States)

Phelps, G.G.

2001-01-01

Increases in chloride concentration have been observed in water from numerous wells tapping the Floridan aquifer system in northeastern Florida. Although most increases have been in the eastern part of Duval County, Florida, no spatial pattern in elevated chloride concentrations is discernible. Possible sources of the mineralized water include modern seawater intrusion; unflushed Miocene-to-Pleistocene-age seawater or connate water in aquifer sediments; or mineralized water from deeper zones of the aquifer system or from formations beneath the Floridan aquifer system. The purpose of this study was to document the chemical and isotopic characteristics of water samples from various aquifer zones, and from geochemical and hydrogeologic data, to infer the source of the increased mineralization. Water samples were collected from 53 wells in northeastern Florida during 1997-1999. Wells tapped various zones of the aquifer including: the Fernandina permeable zone (FPZ), the upper zone of the Lower Floridan aquifer (UZLF), the Upper Floridan aquifer (UFA), and both the UFA and the UZLF. Water samples were analyzed for major ions and trace constituents and for isotopes of carbon, oxygen, hydrogen, sulfur, strontium, chlorine, and boron. Samples of rock from the aquifer were analyzed for isotopes of oxygen, carbon, and strontium. In general, water from various aquifer zones cannot be differentiated based on chemistry, except for water from FPZ wells. Major-ion concentrations vary as much within the upper zone of the Lower Floridan aquifer and the Upper Floridan aquifer as between these two zones. Simple models of mixing between fresh ground water and either modern seawater or water from the FPZ as a mineralized end member show that many water samples from the UZLF aquifer and the UFA are enriched in bicarbonate, calcium, magnesium, sulfate, fluoride, and silica and are depleted in sodium and potassium (as compared to concentrations predicted by simple mixing). Chemical mass

Groundwater vulnerability mapping of Qatar aquifers

Science.gov (United States)

Baalousha, Husam Musa

2016-12-01

Qatar is one of the most arid countries in the world with limited water resources. With little rainfall and no surface water, groundwater is the only natural source of fresh water in the country. Whilst the country relies mainly on desalination of seawater to secure water supply, groundwater has extensively been used for irrigation over the last three decades, which caused adverse environmental impact. Vulnerability assessment is a widely used tool for groundwater protection and land-use management. Aquifers in Qatar are carbonate with lots of fractures, depressions and cavities. Karst aquifers are generally more vulnerable to contamination than other aquifers as any anthropogenic-sourced contaminant, especially above a highly fractured zone, can infiltrate quickly into the aquifer and spread over a wide area. The vulnerability assessment method presented in this study is based on two approaches: DRASTIC and EPIK, within the framework of Geographical Information System (GIS). Results of this study show that DRASTIC vulnerability method suits Qatar hydrogeological settings more than EPIK. The produced vulnerability map using DRASTIC shows coastal and karst areas have the highest vulnerability class. The southern part of the country is located in the low vulnerability class due to occurrence of shale formation within aquifer media, which averts downward movement of contaminants.

Origin and structures of groundwater humic substances from three Danish aquifers

DEFF Research Database (Denmark)

Grøn, C.; Wassenaar, L.; Krog, M.

1996-01-01

and halogens, hydrolyzable amino acids and carbohydrates, carbon isotopes) applied to aquatic humic and fulvic acids led to consistent structural interpretations for each of the three aquifers studied. For humic substances in two-aquifers, the analyses suggested source rocks in agreement with geological......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...

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

QUALITY OF WATERS OF AQUIFER WEBS OF BISKRA REGION

Directory of Open Access Journals (Sweden)

F. Bouchemal

2015-07-01

Full Text Available Controlling the quality of water distributed together with sound resource management is a factor of economic and social development. Also, the chemistry and knowledge of geological and hydrogeological aquifer, the object of this work, we identify the water quality examined through physical-chemical parameters. The study of these parameters more precisely the region of Biskra reveals a generally high mineralized whose origin is essentially the geological nature of enclosing land. However, the waters of the continental interlayer (Albian are the chemical profile weakest; however, its high temperature makes it difficult to use both to supply drinking water as well as for irrigation. After synthesis of the results for different sheets (groundwater, Miopliocene, Eocene, Albian, the limestone is most interesting at least for drinking water, part of its rate of mineralization (medium, the acceptable temperature (24°C and its relatively low salinity    (1 to 3 g/l. However, these waters are not used directly for human consumption. They requires further treatment.

Hydrogeology of the Umm Er Radhuma Aquifer (Arabian peninsula)

Science.gov (United States)

Dirks, Heiko; Al Ajmi, Hussain; Kienast, Peter; Rausch, Randolf

2018-03-01

The aim of this article is to enhance the understanding of the Umm Er Radhuma aquifer's genesis, and its hydraulic and hydrochemical development over time. This is a prerequisite for wise use of the fossil groundwater resources contained within. The Umm Er Radhuma is a karstified limestone aquifer, extending over 1.6 Mio. km2 in the eastern part of the Arabian Peninsula. Both epigene and hypogene karstification contributed to the genesis of what is today the most prolific aquifer in the region. Besides man-made abstractions, even the natural outflows are higher than the small recharge (natural storage depletion). The Umm Er Radhuma shows that large aquifers in arid regions are never in "steady state" (where inflows equal outflows), considering Quaternary climate history. The aquifer's adaption to climate changes (precipitation, sea level) can be traced even after thousands of years, and is slower than the climate changes themselves.

Simulating selenium and nitrogen fate and transport in coupled stream-aquifer systems of irrigated regions

Science.gov (United States)

Shultz, Christopher D.; Bailey, Ryan T.; Gates, Timothy K.; Heesemann, Brent E.; Morway, Eric D.

2018-01-01

Elevated levels of selenium (Se) in aqueous environments can harm aquatic life and endanger livestock and human health. Although Se occurs naturally in the rocks and soils of many alluvial aquifers, mining and agricultural activities can increase its rate of mobilization and transport to surface waters. Attention is given here to regions where nonpoint source return flows from irrigated lands carry pollutant loads to aquifers and streams, contributing to concentrations that violate regulatory and performance standards. Of particular concern is the heightened level and mobilization of Se influenced by nitrate (NO3), a harmful pollutant in its own right. We present a numerical model that simulates the reactive transport of Se and nitrogen (N) species in a coupled groundwater-surface water system. Building upon a conceptual model that incorporates the major processes affecting Se and NO3 transport in an irrigated watershed, the model links the finite-difference models MODFLOW, UZF-RT3D, and OTIS, to simulate flow and reactive transport of multiple chemical species in both the aquifer and a stream network, with mass exchange between the two. The capability of the new model is showcased by calibration, testing, and application to a 500 km2 region in Colorado’s Lower Arkansas River Valley using a rich data set gathered over a 10-yr period. Simulation of spatial and temporal distributions of Se concentration reveals conditions that exceed standards in groundwater for approximately 20% of the area. For the Arkansas River, standards are exceeded by 290%–450%. Simulation indicates that river concentrations of NO3 alone are near the current interim standard for the total of all dissolved N species. These results indicate the need for future use of the developed model to investigate the prospects for land and water best management practices to decrease pollutant levels.

Simulating selenium and nitrogen fate and transport in coupled stream-aquifer systems of irrigated regions

Science.gov (United States)

Shultz, Christopher D.; Bailey, Ryan T.; Gates, Timothy K.; Heesemann, Brent E.; Morway, Eric D.

2018-05-01

Elevated levels of selenium (Se) in aqueous environments can harm aquatic life and endanger livestock and human health. Although Se occurs naturally in the rocks and soils of many alluvial aquifers, mining and agricultural activities can increase its rate of mobilization and transport to surface waters. Attention is given here to regions where nonpoint source return flows from irrigated lands carry pollutant loads to aquifers and streams, contributing to concentrations that violate regulatory and performance standards. Of particular concern is the heightened level and mobilization of Se influenced by nitrate (NO3), a harmful pollutant in its own right. We present a numerical model that simulates the reactive transport of Se and nitrogen (N) species in a coupled groundwater-surface water system. Building upon a conceptual model that incorporates the major processes affecting Se and NO3 transport in an irrigated watershed, the model links the finite-difference models MODFLOW, UZF-RT3D, and OTIS, to simulate flow and reactive transport of multiple chemical species in both the aquifer and a stream network, with mass exchange between the two. The capability of the new model is showcased by calibration, testing, and application to a 500 km2 region in Colorado's Lower Arkansas River Valley using a rich data set gathered over a 10-yr period. Simulation of spatial and temporal distributions of Se concentration reveals conditions that exceed standards in groundwater for approximately 20% of the area. For the Arkansas River, standards are exceeded by 290%-450%. Simulation indicates that river concentrations of NO3 alone are near the current interim standard for the total of all dissolved N species. These results indicate the need for future use of the developed model to investigate the prospects for land and water best management practices to decrease pollutant levels.

Water-level altitudes 2017 and water-level changes in the Chicot, Evangeline, and Jasper Aquifers and compaction 1973–2016 in the Chicot and Evangeline Aquifers, Houston-Galveston region, Texas

Science.gov (United States)

Kasmarek, Mark C.; Ramage, Jason K.

2017-08-16

Most of the land-surface subsidence in the Houston-Galveston region, Texas, has occurred as a direct result of groundwater withdrawals for municipal supply, commercial and industrial use, and irrigation that depressured and dewatered the Chicot and Evangeline aquifers, thereby causing compaction of the aquifer sediments, mostly in the fine-grained silt and clay layers. This report, prepared by the U.S. Geological Survey 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, is one in an annual series of reports depicting water-level altitudes and water-level changes in the Chicot, Evangeline, and Jasper aquifers and measured cumulative compaction of subsurface sediments in the Chicot and Evangeline aquifers in the Houston-Galveston region. This report contains regional-scale maps depicting approximate 2017 water-level altitudes (represented by measurements made during December 2016 through March 2017) and long-term water-level changes for the Chicot, Evangeline, and Jasper aquifers; a map depicting locations of borehole-extensometer (hereinafter referred to as “extensometer”) sites; and graphs depicting measured long-term cumulative compaction of subsurface sediments at the extensometers during 1973–2016.In 2017, water-level-altitude contours for the Chicot aquifer ranged from 200 feet (ft) below the North American Vertical Datum of 1988 (hereinafter referred to as “datum”) in two localized areas in southwestern and northwestern Harris County to 200 ft above datum in west-central Montgomery County. The largest water-level-altitude decline (120 ft) depicted by the 1977–2017 water-level-change contours for the Chicot aquifer was in northwestern Harris County. A broad area where water-level altitudes declined in the Chicot aquifer extends from northwestern, north-central, and southwestern Harris County

Summary of the Snake River plain Regional Aquifer-System Analysis in Idaho and eastern Oregon

Science.gov (United States)

Lindholm, G.F.

1996-01-01

Regional aquifers underlying the 15,600-square-mile Snake River Plain in southern Idaho and eastern Oregon was studied as part of the U.S. Geological Survey's Regional Aquifer-System Analysis program. The largest and most productive aquifers in the Snake River Plain are composed of Quaternary basalt of the Snake River Group, which underlies most of the 10,8000-square-mile eastern plain. Aquifer tests and simulation indicate that transmissivity of the upper 200 feet of the basalt aquifer in the eastern plain commonly ranges from about 100,000 to 1,000,000 feet squared per day. However, transmissivity of the total aquifer thickness may be as much as 10 million feet squared per day. Specific yield of the upper 200 feet of the aquifer ranges from about 0.01 to 0.20. Average horizontal hydraulic conductivity of the upper 200 feet of the basalt aquifer ranges from less than 100 to 9,000 feet per day. Values may be one to several orders of magnitude higher in parts in individual flows, such as flow tops. Vertical hydraulic conductivity is probably several orders of magnitude lower than horizontal hydraulic conductivity and is generally related to the number of joints. Pillow lava in ancestral Snake River channels has the highest hydraulic conductivity of all rock types. Hydraulic conductivity of the basalt decreases with depth because of secondary filling of voids with calcite and silica. An estimated 80 to 120 million acre-feet of water is believed to be stored in the upper 200 feet of the basalt aquifer in the eastern plain. The most productive aquifers in the 4,800-square-mile western plain are alluvial sand and gravel in the Boise River valley. Although aquifer tests indicate that transmissivity of alluvium in the Boise River valley ranges from 5,000 to 160,000 feet squared per day, simulation suggests that average transmissivity of the upper 500 feet is generally less than 20,000 feet squared per day. Vertically averaged horizontal hydraulic conductivity of the upper

Aquifer Treatment of Sea Water to Remove Natural Organic Matter Before Desalination

KAUST Repository

Dehwah, Abdullah

2016-10-18

An investigation of a sea water reverse osmosis desalination facility located in western Saudi Arabia has shown that aquifer treatment of the raw sea water provides a high degree of removal of natural organic matter (NOM) that causes membrane biofouling. The aquifer is a carbonate system that has a good hydraulic connection to the sea and 14 wells are used to induce sea water movement 400 to 450 m from the sea to the wells. During aquifer transport virtually all of the algae, over 90% of the bacteria, over 90% of the biopolymer fraction of NOM, and high percentages of the humic substance, building blocks, and some of the low molecular weight fractions of NOM are removed. Between 44 and over 90% of the transparent exopolymer particles (TEP) are removed with a corresponding significant reduction in concentration of the colloidal fraction of TEP. The removal rate for TEP appears to be greater in carbonate aquifers compared to siliciclastic systems. Although the production wells range in age from 4 months to 14 years, no significant difference in the degree of water treatment provided by the aquifer was found.

Aquifer Treatment of Sea Water to Remove Natural Organic Matter Before Desalination

KAUST Repository

Dehwah, Abdullah; Almashharawi, Samir; Ng, Kim Choon; Missimer, Thomas M.

2016-01-01

An investigation of a sea water reverse osmosis desalination facility located in western Saudi Arabia has shown that aquifer treatment of the raw sea water provides a high degree of removal of natural organic matter (NOM) that causes membrane biofouling. The aquifer is a carbonate system that has a good hydraulic connection to the sea and 14 wells are used to induce sea water movement 400 to 450 m from the sea to the wells. During aquifer transport virtually all of the algae, over 90% of the bacteria, over 90% of the biopolymer fraction of NOM, and high percentages of the humic substance, building blocks, and some of the low molecular weight fractions of NOM are removed. Between 44 and over 90% of the transparent exopolymer particles (TEP) are removed with a corresponding significant reduction in concentration of the colloidal fraction of TEP. The removal rate for TEP appears to be greater in carbonate aquifers compared to siliciclastic systems. Although the production wells range in age from 4 months to 14 years, no significant difference in the degree of water treatment provided by the aquifer was found.

Vertical gradients in water chemistry and age in the Northern High Plains Aquifer, Nebraska, 2003

Science.gov (United States)

McMahon, P.B.; Böhlke, J.K.; Carney, C.P.

2007-01-01

The northern High Plains aquifer is the primary source of water used for domestic, industrial, and irrigation purposes in parts of Colorado, Kansas, Nebraska, South Dakota, and Wyoming. Despite the aquifer’s importance to the regional economy, fundamental ground-water characteristics, such as vertical gradients in water chemistry and age, remain poorly defined. As part of the U.S. Geological Survey’s National Water-Quality Assessment Program, water samples from nested, short-screen monitoring wells installed in the northern High Plains aquifer were analyzed for major ions, nutrients, trace elements, dissolved organic carbon, pesticides, stable and radioactive isotopes, dissolved gases, and other parameters to evaluate vertical gradients in water chemistry and age in the aquifer. Chemical data and tritium and radiocarbon ages show that water in the aquifer was chemically and temporally stratified in the study area, with a relatively thin zone of recently recharged water (less than 50 years) near the water table overlying a thicker zone of older water (1,800 to 15,600 radiocarbon years). In areas where irrigated agriculture was an important land use, the recently recharged ground water was characterized by elevated concentrations of major ions and nitrate and the detection of pesticide compounds. Below the zone of agricultural influence, major-ion concentrations exhibited small increases with depth and distance along flow paths because of rock/water interactions. The concentration increases were accounted for primarily by dissolved calcium, sodium, bicarbonate, sulfate, and silica. In general, the chemistry of ground water throughout the aquifer was of high quality. None of the approximately 90 chemical constituents analyzed in each sample exceeded primary drinking-water standards.Mass-balance models indicate that changes in groundwater chemistry along flow paths in the aquifer can be accounted for by small amounts of feldspar and calcite dissolution; goethite

Comparison of groundwater flow in Southern California coastal aquifers

Science.gov (United States)

Hanson, Randall T.; Izbicki, John A.; Reichard, Eric G.; Edwards, Brian D.; Land, Michael; Martin, Peter

2009-01-01

Development of the coastal aquifer systems of Southern California has resulted in overdraft, changes in streamflow, seawater intrusion, land subsidence, increased vertical flow between aquifers, and a redirection of regional flow toward pumping centers. These water-management challenges can be more effectively addressed by incorporating new understanding of the geologic, hydrologic, and geochemical setting of these aquifers.

Integration of crosswell seismic data for simulating porosity in a heterogeneous carbonate aquifer

Science.gov (United States)

Emery, Xavier; Parra, Jorge

2013-11-01

A challenge for the geostatistical simulation of subsurface properties in mining, petroleum and groundwater applications is the integration of well logs and seismic measurements, which can provide information on geological heterogeneities at a wide range of scales. This paper presents a case study conducted at the Port Mayaca aquifer, located in western Martin County, Florida, in which it is of interest to simulate porosity, based on porosity logs at two wells and high-resolution crosswell seismic measurements of P-wave impedance. To this end, porosity and impedance are transformed into cross-correlated Gaussian random fields, using local transformations. The model parameters (transformation functions, mean values and correlation structure of the transformed fields) are inferred and checked against the data. Multiple realizations of porosity can then be constructed conditionally to the impedance information in the interwell region, which allow identifying one low-porosity structure and two to three flow units that connect the two wells, mapping heterogeneities within these units and visually assessing fluid paths in the aquifer. In particular, the results suggest that the paths in the lower flow units, formed by a network of heterogeneous conduits, are not as smooth as in the upper flow unit.

Continental hydrosystem modelling: the concept of nested stream-aquifer interfaces

Science.gov (United States)

Flipo, N.; Mouhri, A.; Labarthe, B.; Biancamaria, S.; Rivière, A.; Weill, P.

2014-08-01

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. Based on an extensive literature review, stream-aquifer interfaces are described at five different scales: local [10 cm-~10 m], intermediate [~10 m-~1 km], watershed [10 km2-~1000 km2], regional [10 000 km2-~1 M km2] and continental scales [>10 M km2]. This led us to develop the concept of nested stream-aquifer interfaces, which extends the well-known vision of nested groundwater pathways towards the surface, where the mixing of low frequency processes and high frequency processes coupled with the complexity of geomorphological features and heterogeneities creates hydrological spiralling. This conceptual framework allows the identification of a hierarchical order of the multi-scale control factors of stream-aquifer hydrological exchanges, from the larger scale to the finer scale. The hyporheic corridor, which couples the river to its 3-D hyporheic zone, is then identified as the key component for scaling hydrological processes occurring at the interface. The identification of the hyporheic corridor as the support of the hydrological processes scaling is an important step for the development of regional studies, which is one of the main concerns for water practitioners and resources managers. In a second part, the modelling of the stream-aquifer interface at various scales is investigated with the help of the conductance model. Although the usage of the temperature as a tracer of the flow is a robust method for the assessment of stream-aquifer exchanges at the local scale, there is a crucial need to develop innovative methodologies for assessing stream-aquifer exchanges at the regional scale. After formulating the conductance model at the regional and intermediate scales, we address this challenging issue with the development of an

The addition of organic carbon and nitrate affects reactive transport of heavy metals in sandy aquifers

KAUST Repository

Satyawali, Yamini

2011-04-01

Organic carbon introduction in the soil to initiate remedial measures, nitrate infiltration due to agricultural practices or sulphate intrusion owing to industrial usage can influence the redox conditions and pH, thus affecting the mobility of heavy metals in soil and groundwater. This study reports the fate of Zn and Cd in sandy aquifers under a variety of plausible in-situ redox conditions that were induced by introduction of carbon and various electron acceptors in column experiments. Up to 100% Zn and Cd removal (from the liquid phase) was observed in all the four columns, however the mechanisms were different. Metal removal in column K1 (containing sulphate), was attributed to biological sulphate reduction and subsequent metal precipitation (as sulphides). In the presence of both nitrate and sulphate (K2), the former dominated the process, precipitating the heavy metals as hydroxides and/or carbonates. In the presence of sulphate, nitrate and supplemental iron (Fe(OH)3) (K3), metal removal was also due to precipitation as hydroxides and/or carbonates. In abiotic column, K4, (with supplemental iron (Fe(OH)3), but no nitrate), cation exchange with soil led to metal removal. The results obtained were modeled using the reactive transport model PHREEQC-2 to elucidate governing processes and to evaluate scenarios of organic carbon, sulphate and nitrate inputs. © 2010 Elsevier B.V.

Clay Mineralogy of AN Alluvial Aquifer in a Mountainous, Semiarid Terrain, AN Example from Rifle, Colorado

Science.gov (United States)

Elliott, W. C.; Lim, D.; Zaunbrecher, L. K.; Pickering, R. A.; Williams, K. H.; Navarre-Sitchler, A.; Long, P. E.; Noel, V.; Bargar, J.; Qafoku, N. P.

2015-12-01

Alluvial sediments deposited along the Colorado River corridor in the semi-arid regions of central to western Colorado can be important hosts for legacy contamination including U, V, As and Se. These alluvial sediments host aquifers which are thought to provide important "hot spots" and "hot moments" for microbiological activity controlling organic carbon processing and fluxes in the subsurface. Relatively little is known about the clay mineralogy of these alluvial aquifers and the parent alluvial sediments in spite of the fact that they commonly include lenses of silt-clay materials. These lenses are typically more reduced than coarser grained materials, but zones of reduced and more oxidized materials are present in these alluvial aquifer sediments. The clay mineralogy of the non-reduced parent alluvial sediments of the alluvial aquifer located in Rifle, CO (USA) is composed of chlorite, smectite, illite, kaolinite and quartz. The clay mineralogy of non-reduced fine-grained materials at Rifle are composed of the same suite of minerals found in the sediments plus a vermiculite-smectite intergrade that occurs near the bottom of the aquifer near the top of the Wasatch Formation. The clay mineral assemblages of the system reflect the mineralogically immature character of the source sediments. These assemblages are consistent with sediments and soils that formed in a moderately low rainfall climate and suggestive of minimal transport of the alluvial sediments from their source areas. Chlorite, smectite, smectite-vermiculite intergrade, and illite are the likely phases involved in the sorption of organic carbon and related microbial redox transformations of metals in these sediments. Both the occurrence and abundance of chlorite, smectite-vermiculite, illite and smectite can therefore exert an important control on the contaminant fluxes and are important determinants of biogeofacies in mountainous, semiarid terrains.

Geologic Setting and Hydrogeologic Units of the Columbia Plateau Regional Aquifer System, Washington, Oregon, and Idaho

Science.gov (United States)

Kahle, Sue C.; Olsen, Theresa D.; Morgan, David S.

2009-01-01

The Columbia Plateau Regional Aquifer System (CPRAS) covers approximately 44,000 square miles of northeastern Oregon, southeastern Washington, and western Idaho. The area supports a $6 billion per year agricultural industry, leading the Nation in production of apples and nine other commodities (State of Washington Office of Financial Management, 2007; U.S. Department of Agriculture, 2007). Groundwater availability in the aquifers of the area is a critical water-resource management issue because the water demand for agriculture, economic development, and ecological needs is high. The primary aquifers of the CPRAS are basalts of the Columbia River Basalt Group (CRBG) and overlying basin-fill sediments. Water-resources issues that have implications for future groundwater availability in the region include (1) widespread water-level declines associated with development of groundwater resources for irrigation and other uses, (2) reduction in base flow to rivers and associated effects on temperature and water quality, and (3) current and anticipated effects of global climate change on recharge, base flow, and ultimately, groundwater availability. As part of a National Groundwater Resources Program, the U.S. Geological Survey began a study of the CPRAS in 2007 with the broad goals of (1) characterizing the hydrologic status of the system, (2) identifying trends in groundwater storage and use, and (3) quantifying groundwater availability. The study approach includes documenting changes in the status of the system, quantifying the hydrologic budget for the system, updating the regional hydrogeologic framework, and developing a groundwater-flow simulation model for the system. The simulation model will be used to evaluate and test the conceptual model of the system and later to evaluate groundwater availability under alternative development and climate scenarios. The objectives of this study were to update the hydrogeologic framework for the CPRAS using the available

Water quality of the Mississippian carbonate aquifer in parts of middle Tennessee and northern Alabama, 1999

Science.gov (United States)

Kingsbury, James A.; Shelton, John M.

2002-01-01

Water-quality data for nitrate, fecal-indicator bacteria, pesticides, and volatile organic compounds collected in parts of Middle Tennessee and northern Alabama indicate that the Mississippian carbonate aquifer in these areas is susceptible to contamination from point and nonpoint sources. Thirty randomly located wells (predominantly domestic), two springs, and two additional public-supply wells were sampled in the summer of 1999 as part of the U.S. Geological Survey?s National Water-Quality Assessment (NAWQA) Program. These wells and springs were sampled to characterize the occurrence and distribution of the above constituents in this karst aquifer of Mississippian age and to determine the principal environmental factors related to their occurrence.Nitrate and fecal indicator bacteria were frequently detected at the sampled sites. Nitrate exceeded the drinking-water maximum contaminant level of 10 milligrams per liter in two samples; the median concentration for all samples was about 1.5 milligrams per liter. Correlation of nitrate concentrations to the amount of cropland near a site and to pesticide detections indicates that fertilizer application is the predominant source of nitrogen to the aquifer. Fecal-indicator bacteria were present in samples from about 40 percent of the sites. The presence of fecal-indicator bacteria is weakly correlated to the depth to ground water but is not correlated to a specific land use near the sites.Pesticides and pesticide breakdown products (metabolites) were detected at 74 percent of the sites sampled. Concentrations generally were less than 1 microgram per liter and no pesticide detections exceeded drinking-water maximum contaminant levels. The maximum total pesticide concentration measured was about 4 micrograms per liter. Intensity of pesticide use, proximity of sites to areas of pesticide application, and soil hydrologic group were the primary factors affecting the occurrence of pesticides.Volatile organic compounds were

A New Boundary for the High Plains - Ogallala Aquifer Complex

Science.gov (United States)

Haacker, E. M.; Nozari, S.; Kendall, A. D.

2017-12-01

In the semi-arid Great Plains, water is the key ingredient for crop growth: the difference between meager yields for many crops and an agricultural bonanza. The High Plains-Ogallala Aquifer complex (HPA) underlies 452,000 square kilometers of the region, and over 95% of water withdrawn from the aquifer is used for irrigation. Much of the HPA is being pumped unsustainably, and since the region is heavily reliant on this resource for its social and economic health, the High Plains has been a leader in groundwater management planning. However, the geographic boundary of the High Plains region fails to reflect the hydrogeological realities of the aquifer. The current boundary, recognizable from countless textbooks and news articles, is only slightly modified from a version from the 1980's, and largely follows the physiographic borders of the High Plains - defined by surface features such as escarpments and rivers - rather than the edges of water-bearing sediment sufficient for high-volume pumping. This is supported by three lines of evidence: hydrogeological observations from the original aquifer boundary determination; the extent of irrigated land, as estimated by MODIS-MIrAD data; and statistical estimates of saturated thickness, incorporating improved maps of the aquifer base and an additional 35 years of water table measurements. In this project, new maps of saturated thickness are used to create an updated aquifer boundary, which conforms with the standard definition of an aquifer as a package of sediment that yields enough water to be economically pumped. This has major implications for social and physical models, as well as water planning and estimates of sustainability for the HPA. Much of the area of the HPA that has been labeled `sustainable' based upon estimates of recharge relative to pumping estimates falls outside the updated aquifer boundary. In reality, the sustainably-pumped area of this updated aquifer boundary is far smaller—a fact that if more

Hydrogeology of the cave Vetrovna jama in karst aquifer north from Planinsko polje (Notranjska region, central Slovenia

Directory of Open Access Journals (Sweden)

Franci Gabrovšek

2009-06-01

Full Text Available For one year we have been measuring level and temperature of underground water in Vetrovna jama, to find outthe origin of underground water and hydraulic characteristics of the cave and karst aquifer north east of Planinsko polje (karst of Notranjska region, central Slovenia. Similar parameters as in Vetrovna jama were measured also at the Unica River and at the Cerknica Lake. Cave is located only 2.7 km north from the polje and is fed by the Unica River, according to measurements. But in contrast with our expectations, we did not directly detect undergroundwater flow, which drains from the Cerknica Lake. Hydrographs measured in Vetrovna jama were compared with those measured in some other caves within the aquifer. Hydrographs from Vetrovna jama are only partly comparablewith hydrographs obtained in other monitored caves, as comparison shows no statistical significant correlation.Final conclusion would be that drainage of water between “eastern” and “western” part of karst aquifer islimited. More over, out flow from Vetrovna jama strongly depends on local hydrogeological restriction, such as supposedrockfall under Laška kukava collapse doline.

State and Regional Control of Geological Carbon Sequestration

Energy Technology Data Exchange (ETDEWEB)

Reitze, Arnold [Univ. of Utah, Salt Lake City, UT (United States); Durrant, Marie [Univ. of Utah, Salt Lake City, UT (United States)

2011-03-01

The United States has economically recoverable coal reserves of about 261 billion tons, which is in excess of a 250-­year supply based on 2009 consumption rates. However, in the near future the use of coal may be legally restricted because of concerns over the effects of its combustion on atmospheric carbon dioxide concentrations. Carbon capture and geologic sequestration offer one method to reduce carbon emissions from coal and other hydrocarbon energy production. While the federal government is providing increased funding for carbon capture and sequestration, recent congressional legislative efforts to create a framework for regulating carbon emissions have failed. However, regional and state bodies have taken significant actions both to regulate carbon and facilitate its capture and sequestration. This article explores how regional bodies and state government are addressing the technical and legal problems that must be resolved in order to have a viable carbon sequestration program. Several regional bodies have formed regulations and model laws that affect carbon capture and storage, and three bodies comprising twenty-three states—the Regional Greenhouse Gas Initiative, the Midwest Regional Greenhouse Gas Reduction Accord, and the Western Climate initiative—have cap-­and-trade programs in various stages of development. State property, land use and environmental laws affect the development and implementation of carbon capture and sequestration projects, and unless federal standards are imposed, state laws on torts and renewable portfolio requirements will directly affect the liability and viability of these projects. This paper examines current state laws and legislative efforts addressing carbon capture and sequestration.

Model-based assessment of the potential of seasonal aquifer thermal energy storage and recovery as a groundwater ecosystem service for the Brussels-Capital Region

Science.gov (United States)

Anibas, Christian; Huysmans, Marijke

2015-04-01

Urban areas are characterized by their concentrated demand of energy, applying a high pressure on urban ecosystems including atmosphere, soils and groundwater. In the light of global warming, urbanization and an evolving energy system, it is important to know how urbanized areas can contribute to their own energy demands. One option is to use the possibilities aquifers offer as an ecosystem service (BONTE et al., 2011). If used effectively an improvement in air and groundwater quality is achieved. Additionally, the more efficient distribution of the used energy may also lead to a decrease in primary energy consumption (ZUURBIER, 2013). Therefore, investigations of the potential of seasonal aquifer thermal energy storage and recovery (ATES) for the Brussels-Capital Region, Belgium is being conducted. The potential of ATES systems are of special interest for energy demands in high density urban areas because of such infrastructure as office buildings, schools, hospitals and shopping malls. In an open water circuit ATES systems consist of two or more groundwater wells, where in seasonal cycles one subtracts and the other recharges water to the aquifer. Heat pumps use the heat capacity of water for heating or cooling a building. An important limitation of the methodology is the quality of the groundwater used (i.e. precipitation of Fe- or Mn-oxides can decrease the yield). However, ATES systems on the other hand can also improve groundwater quality and groundwater ecosystems. The current knowledge of the potential for ATES systems in the Brussels-Capital Region is based on geological assessments from VITO (2007). The Brussels-Capital Region is divided into a western and eastern section with respect to geology. While the western part has less favorable conditions for ATES, the eastern is composed of the Brussels Sand formation, which is a 20-40 m thick aquifer layer that has the highest potential for ATES systems in the region. By applying groundwater flow and heat

Aquifer recharging in South Carolina: radiocarbon in environmental hydrogeology

International Nuclear Information System (INIS)

Stone, P.A.; Knox, R.L.; Mathews, T.D.

1985-01-01

Radiocarbon activities of dissolved inorganic carbon (and tritium activities where infiltration rates are rapid and aquifers shallow) provide relatively unambiguous and inexpensive evidence for identification of significant recharge areas. Such evidence is for the actual occurrence of modern recharge in the aquifer and thus is less inferential than stratigraphic or potentiometric evidence. These underutilized isotopic techniques are neither arcane nor complex and have been more-or-less standardized by earlier researchers. In South Carolina, isotopic evidence has been used from both calcareous and siliceous sedimentary aquifers and fractured crystalline rock aquifers. The Tertiary limestone aquifer is shown not to be principally recharged in its subcrop area, unlike conditions assumed for many other sedimentary aquifers in southeastern United States, and instead receives considerable lateral recharge from interfingering updip Tertiary sand aquifers in the middle coastal plain. Induced recharging at Hilton Head Island is mixing ancient relict water and modern recharge water. Recharging to deeper portions of the Cretaceous Middendorf basal sand aquifer occurs at least as far coastward as the middle coastal plain, near sampling sites that stratigraphically appear to be confined. Pronounced mineralization of water in fractured rocks cannot be considered as evidence of ancient or relict ground water that is isolated from modern contaminants, some of these waters contain considerable radiocarbon and hydrogen-bomb tritium

Geochemical Characterization of the Upper and Middle Floridan Aquifer System, South Florida

Science.gov (United States)

Mirecki, J.; Richardson, E.; Bennett, M.; Hendel, J.

2008-05-01

Our study focus is to characterize the water quality and geochemical environment of the Floridan Aquifer System (FAS) throughout the regional flowpath. A synoptic survey of 21 wells (n=15, upper FAS; n=6 middle FAS) was supplemented by additional samples (n=11) obtained during exploratory well development at 4 aquifer storage recovery (ASR) pilot sites. Synoptic survey samples were analyzed intensively, yielding a dataset that consists of major and trace dissolved constituents (including metals), stable isotopes (δ18O, δ13C, δD, δ34S in sulfate and sulfide), carbon species (carbonate alkalinity and organic carbon), uranium-series radionuclides, nutrients, and selected microbes and pathogens. The objectives of this study are three-fold: 1) to provide baseline water-quality and geochemical information prior to initiation of ASR activities that are part of the Comprehensive Everglades Restoration Plan; 2) to quantify the major controls on geochemical evolution along upper and middle FAS flowpaths using geochemical modeling methods; and 3) to identify areas where water- quality may limit the feasibility of ASR methods in the FAS. Preliminary interpretations water quality changes along the regional FAS flowpath can be summarized as follows. Concentrations of dissolved constituents increase from north to south along the flow path; generally, the upper FAS has lower total dissolved solids than the middle FAS at locations where well pairs were analyzed. The redox environment changes from oxic to strongly anoxic, very close to the recharge area. Redox measurements, dissolved iron, sulfide, and sulfur isotope data are consistent with sulfate-reducing conditions. Uranium-series isotope concentrations and activities generally are below regulatory criteria, with few exceptions in both the upper and middle FAS. Areas with greater radionuclide activity occur primarily at distal flowpath locations or at the coast.

Natural isotopes and water stratification in the Judea Group aquifer (Judea Desert)

International Nuclear Information System (INIS)

Kornfeld, Loel; Vogel, John C.; Rosenthal, Asher

1992-01-01

Using environmental isotopes, the subaquifer of the Judea Group carbonate aquifer were studied from the recharge area in the Judea Hills, eastwords down the flanks of the escarpment to the Jordan River Valley. The oxygen isotope data confirms that the dominant source of recharge for the phreatic and confined subaquifers in the Judean Hills. Water-rock interactions develop the δ 13 C values rapidly in the recharge region. once established where is no significant subsequent modification due to interaction with the enveloping carbonate as the water travels down dip. The relative high tritium values encountered in the springs and several of the well waters would indicate modern waters. However, the low radiocarbon levels are often encountered in the same water sources implies that a mixture of young water with significanly older water has been encountered. There are indications, at least in the upper subaquifer, of agewise stratification of the waters. Water is transmitted very rapidly through the upper portions of the aquifer while the water in the lower portions may be moving slowly because of the low permeability. The timing of the recharge of the deeper portion of the subaquifer and much of the lower subaquifer occurred in the mid-to early Holocene. (authors)

Sequestration of carbon in saline aquifers - mathematical and numerical analysis

Energy Technology Data Exchange (ETDEWEB)

Nordbotten, Jan Martin

2004-01-01

The work in this thesis focuses equally on two main topics. The set of these subjects deals with development of criteria for monotonicity of control volume methods. These methods are important and frequently used for solving the pressure equation arising in porous media flow. First we consider homogeneous parallelogram grids, and subsequently general logical Cartesian grids in heterogeneous media. This subject is concluded by the development of a new class of Multi Point Flux Approximation methods, motivated by the monotonicity results obtained. The second topic of this thesis is the development of analytical and semi- analytical solutions to the problem of leakage through abandoned wells. More specially, we look at a set of aquifers, separated by impermeable layers (aquicludes), where injection of water or CO{sub 2} takes place in some or all the aquifers. The aquifers and aquicludes are frequently penetrated by abandoned wells from oil exploration, and our problem consists of finding solutions to flow and leakage through these wells. The goal is to obtain expressions for leakage rates that may be evaluated quickly enough such that Monte Carlo realizations over statistical distributions of properties for abandoned wells can be performed. (author)

River Intrusion in Karst Springs in Eogenetic Aquifers: Implications for Speleogenesis

Science.gov (United States)

Martin, J. B.; Gulley, J.; Screaton, E. J.

2008-12-01

Conceptual models of speleogenesis generally assume uni-directional transport in integrated conduit systems from discrete recharge points to discharge at karst springs. Estavelles, however, are karst springs that function intermittently as discrete recharge points when river stage rises more rapidly than local aquifer heads. As river water chemistry changes between baseflow and floods, estavelles should influence mass transport through (e.g. organic carbon, nutrients, and oxygen) and speleogenesis within karst systems. Estavelles are common in our study area in north-central Florida, particularly along the lower reaches of the Santa Fe River, where it flows across the unconfined karstic Floridan aquifer. River stage in this unconfined region can rise much faster than aquifer heads when large amounts of rain fall on the confined regions in its upper reaches. Backflooding into the estavelles during elevated river stage drives river water into the ground, causing some springs to reverse and other springs to recirculate large volumes of river water. Floodwaters originating in the confined region are highly undersaturated with respect to calcite, and thus river water transitions from slightly supersaturated to highly undersaturated with respect to calcite during flood events. As a result, conduits connected to estavelles are continuously enlarged as springs reverse or recirculate calcite-undersaturated river water. It has been suggested that currently flooded caves (i.e. karst conduits) associated with springs in Florida formed entirely underwater because speleothems, which are prevalent in flooded caves in the Yucatan and Bahamas, have not been observed by cave divers. Results of this study indicate that the absence of speleothems does not necessarily provide evidence of a continuous phreatic history for underwater caves. Instead speleothems that formed in caves while dry could have been dissolved by backflooding of estavelles with undersaturated water

Groundwater vulnerability assessment in karstic aquifers using COP method.

Science.gov (United States)

Bagherzadeh, Somayeh; Kalantari, Nasrollah; Nobandegani, Amir Fadaei; Derakhshan, Zahra; Conti, Gea Oliveri; Ferrante, Margherita; Malekahmadi, Roya

2018-05-02

Access to safe and reliable drinking water is amongst the important indicators of development in each society, and water scarcity is one of the challenges and limitations affecting development at national and regional levels and social life and economic activity areas. Generally, there are two types of drinking water sources: the first type is surface waters, including lakes, rivers, and streams and the second type is groundwaters existing in aquifers. Amongst aquifers, karst aquifers play an important role in supplying water sources of the world. Therefore, protecting these aquifers from pollution sources is of paramount importance. COP method is amongst the methods to investigate the intrinsic vulnerability of this type of aquifers, so that areas susceptible to contamination can be determined before being contaminated and these sources can be protected. In the present study, COP method was employed in order to spot the regions that are prone to contamination in the region. This method uses the properties of overlying geological layers above the water table (O factor), the concentration of flow (C factor), and precipitation (P factor) over the aquifer, as the parameters to assess the intrinsic vulnerability of groundwater resources. In this regard, geographical information system (GIS) and remote sensing (RS) were utilized to prepare the mentioned factors and the intrinsic vulnerability map was obtained. The results of COP method indicated that the northwest and the west of the region are highly and very vulnerable. This study indicated that regions with low vulnerability were observed in eastern areas, which accounted for 15.6% of the area. Moderate vulnerability was 40% and related to the northeast and southeast of the area. High vulnerability was 38.2% and related to western and southwestern regions. Very high vulnerability was 6.2% and related to the northwest of the area. By means of the analysis of sensitivity of the model, it was determined that the focus

Hydrogeology of the Besparmak (Pentadactilos) Mountains (TRNC) Karstic Aquifer

International Nuclear Information System (INIS)

Erduran, B.; Goekmenoglu, O.; Keskin, E.

2002-01-01

The Besparmak Mountains are located on the Nothern part of North Cyprus and lay paralel to the sea, 160 km 2 in length 10 km in width. Karstification, potential constituent and the hydro-dynamic structure of the Mesosoic aged carbonate rocks, located at high altitudes of the Besparmak Mountains have been investigated in this study. The Mesosoic aged carbonate rocks; dolomite, dolomitic limestones and recrytallized limestones are yhe units suitable for karstification in the exploration area. Surface area of the carbonate rocks is 84 km 2 . Chemical and isotopic samples have been collected, groundwater fluctuations have been observed and investigation wells have been openned for the definition of the karst aquifer. As the result of the geological, hydrogeological, drilling and geophysical investigations it was found that the Besparmak Mountains Karst Aquifer was formed of independent karstic systems and a total dynamic groundwater potential of aproximately 9 x 10 6 m 3 /year for these systems has been determined

Estimating Aquifer Properties Using Sinusoidal Pumping Tests

Science.gov (United States)

Rasmussen, T. C.; Haborak, K. G.; Young, M. H.

2001-12-01

We develop the theoretical and applied framework for using sinusoidal pumping tests to estimate aquifer properties for confined, leaky, and partially penetrating conditions. The framework 1) derives analytical solutions for three boundary conditions suitable for many practical applications, 2) validates the analytical solutions against a finite element model, 3) establishes a protocol for conducting sinusoidal pumping tests, and 4) estimates aquifer hydraulic parameters based on the analytical solutions. The analytical solutions to sinusoidal stimuli in radial coordinates are derived for boundary value problems that are analogous to the Theis (1935) confined aquifer solution, the Hantush and Jacob (1955) leaky aquifer solution, and the Hantush (1964) partially penetrated confined aquifer solution. The analytical solutions compare favorably to a finite-element solution of a simulated flow domain, except in the region immediately adjacent to the pumping well where the implicit assumption of zero borehole radius is violated. The procedure is demonstrated in one unconfined and two confined aquifer units near the General Separations Area at the Savannah River Site, a federal nuclear facility located in South Carolina. Aquifer hydraulic parameters estimated using this framework provide independent confirmation of parameters obtained from conventional aquifer tests. The sinusoidal approach also resulted in the elimination of investigation-derived wastes.

Machine-readable files developed for the High Plains Regional Aquifer-System analysis in parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming

Science.gov (United States)

Ferrigno, C.F.

1986-01-01

Machine-readable files were developed for the High Plains Regional Aquifer-System Analysis project are stored on two magnetic tapes available from the U.S. Geological Survey. The first tape contains computer programs that were used to prepare, store, retrieve, organize, and preserve the areal interpretive data collected by the project staff. The second tape contains 134 data files that can be divided into five general classes: (1) Aquifer geometry data, (2) aquifer and water characteristics , (3) water levels, (4) climatological data, and (5) land use and water use data. (Author 's abstract)

Fate of Arsenic during Red River Water Infiltration into Aquifers beneath Hanoi, Vietnam.

Science.gov (United States)

Postma, Dieke; Mai, Nguyen Thi Hoa; Lan, Vi Mai; Trang, Pham Thi Kim; Sø, Helle Ugilt; Nhan, Pham Quy; Larsen, Flemming; Viet, Pham Hung; Jakobsen, Rasmus

2017-01-17

Recharge of Red River water into arsenic-contaminated aquifers below Hanoi was investigated. The groundwater age at 40 m depth in the aquifer underlying the river was 1.3 ± 0.8 years, determined by tritium-helium dating. This corresponds to a vertical flow rate into the aquifer of 19 m/year. Electrical conductivity and partial pressure of CO 2 (P CO 2 ) indicate that water recharged from the river is present in both the sandy Holocene and gravelly Pleistocene aquifers and is also abstracted by the pumping station. Infiltrating river water becomes anoxic in the uppermost aquifer due to the oxidation of dissolved organic carbon. Further downward, sedimentary carbon oxidation causes the reduction of As-containing Fe-oxides. Because the release of arsenic by reduction of Fe-oxides is controlled by the reaction rate, arsenic entering the solution becomes highly diluted in the high water flux and contributes little to the groundwater arsenic concentration. Instead, the As concentration in the groundwater of up to 1 μM is due to equilibrium-controlled desorption of arsenic, adsorbed to the sediment before river water started to infiltrate due to municipal pumping. Calculations indicate that it will take several decades of river water infiltration to leach arsenic from the Holocene aquifer to below the World Health Organization limit of 10 μg/L.

Fate of Arsenic during Red River Water Infiltration into Aquifers beneath Hanoi, Vietnam

Science.gov (United States)

2016-01-01

Recharge of Red River water into arsenic-contaminated aquifers below Hanoi was investigated. The groundwater age at 40 m depth in the aquifer underlying the river was 1.3 ± 0.8 years, determined by tritium–helium dating. This corresponds to a vertical flow rate into the aquifer of 19 m/year. Electrical conductivity and partial pressure of CO2 (PCO2) indicate that water recharged from the river is present in both the sandy Holocene and gravelly Pleistocene aquifers and is also abstracted by the pumping station. Infiltrating river water becomes anoxic in the uppermost aquifer due to the oxidation of dissolved organic carbon. Further downward, sedimentary carbon oxidation causes the reduction of As-containing Fe-oxides. Because the release of arsenic by reduction of Fe-oxides is controlled by the reaction rate, arsenic entering the solution becomes highly diluted in the high water flux and contributes little to the groundwater arsenic concentration. Instead, the As concentration in the groundwater of up to 1 μM is due to equilibrium-controlled desorption of arsenic, adsorbed to the sediment before river water started to infiltrate due to municipal pumping. Calculations indicate that it will take several decades of river water infiltration to leach arsenic from the Holocene aquifer to below the World Health Organization limit of 10 μg/L. PMID:27958705

Estimating aquifer properties from the water level response to Earth tides.

Science.gov (United States)

Cutillo, Paula A; Bredehoeft, John D

2011-01-01

Water level fluctuations induced by tidal strains can be analyzed to estimate the elastic properties, porosity, and transmissivity of the surrounding aquifer material. We review underutilized methods for estimating aquifer properties from the confined response to earth tides. The earth tide analyses are applied to an open well penetrating a confined carbonate aquifer. The resulting range of elastic and hydraulic aquifer properties are in general agreement with that determined by other investigators for the area of the well. The analyses indicate that passive monitoring data from wells completed in sufficiently stiff, low porosity formations can provide useful information on the properties of the surrounding formation. Journal compilation © 2010 National Ground Water Association. No claim to original US government works.

Modeling aquifer behaviour under climate change and high consumption: Case study of the Sfax region, southeast Tunisia

Science.gov (United States)

Boughariou, Emna; Allouche, Nabila; Jmal, Ikram; Mokadem, Naziha; Ayed, Bachaer; Hajji, Soumaya; Khanfir, Hafedh; Bouri, Salem

2018-05-01

The water resources are exhausted by the increasing demand related to the population growth. They are also affected by climate circumstances, especially in arid and semi-arid regions. These areas are already undergoing noticeable shortages and low annual precipitation rate. This paper presents a numerical model of the Sfax shallow aquifer system that was developed by coupling the geographical information system tool ArcGIS 9.3 and ground water modeling system GMS6.5's interface, ground water flow modeling MODFLOW 2000. Being in coastal city and having an arid climate with high consumption rates, this aquifer is undergoing a hydraulic stress situation. Therefore, the groundwater piezometric variations were calibrated for the period 2003-2013 and simulated based on two scenarios; first the constant and growing consumption and second the rainfall forecast as a result of climate change scenario released by the Tunisian Ministry of Agriculture and Water Resources and the German International Cooperation Agency "GIZ" using HadCM3 as a general circulation model. The piezometric simulations globally forecast a decrease that is about 0.5 m in 2020 and 1 m in 2050 locally the decrease is more pronounced in "Chaffar" and "Djbeniana" regions and that is more evident for the increasing consumption scenario. The two scenarios announce a quantitative degradation of the groundwater by the year 2050 with an alarming marine intrusion in "Djbeniana" region.

Development of a regional groundwater flow model for the area of the Idaho National Engineering Laboratory, Eastern Snake River Plain Aquifer

International Nuclear Information System (INIS)

McCarthy, J.M.; Arnett, R.C.; Neupauer, R.M.

1995-03-01

This report documents a study conducted to develop a regional groundwater flow model for the Eastern Snake River Plain Aquifer in the area of the Idaho National Engineering Laboratory. The model was developed to support Waste Area Group 10, Operable Unit 10-04 groundwater flow and transport studies. The products of this study are this report and a set of computational tools designed to numerically model the regional groundwater flow in the Eastern Snake River Plain aquifer. The objective of developing the current model was to create a tool for defining the regional groundwater flow at the INEL. The model was developed to (a) support future transport modeling for WAG 10-04 by providing the regional groundwater flow information needed for the WAG 10-04 risk assessment, (b) define the regional groundwater flow setting for modeling groundwater contaminant transport at the scale of the individual WAGs, (c) provide a tool for improving the understanding of the groundwater flow system below the INEL, and (d) consolidate the existing regional groundwater modeling information into one usable model. The current model is appropriate for defining the regional flow setting for flow submodels as well as hypothesis testing to better understand the regional groundwater flow in the area of the INEL. The scale of the submodels must be chosen based on accuracy required for the study

SOUTHWEST REGIONAL PARTNERSHIP ON CARBON SEQUESTRATION

Energy Technology Data Exchange (ETDEWEB)

Brian McPherson; Rick Allis; Barry Biediger; Joel Brown; Jim Cappa; George Guthrie; Richard Hughes; Eugene Kim; Robert Lee; Dennis Leppin; Charles Mankin; Orman Paananen; Rajesh Pawar; Tarla Peterson; Steve Rauzi; Jerry Stuth; Genevieve Young

2004-11-01

The Southwest Partnership Region includes six whole states, including Arizona, Colorado, Kansas, New Mexico, Oklahoma, and Utah, roughly one-third of Texas, and significant portions of adjacent states. The Partnership comprises a large, diverse group of expert organizations and individuals specializing in carbon sequestration science and engineering, as well as public policy and outreach. The main objective of the Southwest Partnership project is to achieve an 18% reduction in carbon intensity by 2012. The Partnership made great progress in this first year. Action plans for possible Phase II carbon sequestration pilot tests in the region are almost finished, including both technical and non-technical aspects necessary for developing and carrying out these pilot tests. All partners in the Partnership are taking an active role in evaluating and ranking optimum sites and technologies for capture and storage of CO{sub 2} in the Southwest Region. We are identifying potential gaps in all aspects of potential sequestration deployment issues.

Soil aquifer treatment of artificial wastewater under saturated conditions

KAUST Repository

Essandoh, H. M K; Tizaoui, Chedly; Mohamed, Mostafa H A; Amy, Gary L.; Brdjanovic, Damir

2011-01-01

A 2000 mm long saturated laboratory soil column was used to simulate soil aquifer treatment under saturated conditions to assess the removal of chemical and biochemical oxygen demand (COD and BOD), dissolved organic carbon (DOC), nitrogen

CO2/Brine transport into shallow aquifers along fault zones.

Science.gov (United States)

Keating, Elizabeth H; Newell, Dennis L; Viswanathan, Hari; Carey, J W; Zyvoloski, G; Pawar, Rajesh

2013-01-02

Unintended release of CO(2) from carbon sequestration reservoirs poses a well-recognized risk to groundwater quality. Research has largely focused on in situ CO(2)-induced pH depression and subsequent trace metal mobilization. In this paper we focus on a second mechanism: upward intrusion of displaced brine or brackish-water into a shallow aquifer as a result of CO(2) injection. Studies of two natural analog sites provide insights into physical and chemical mechanisms controlling both brackish water and CO(2) intrusion into shallow aquifers along fault zones. At the Chimayó, New Mexico site, shallow groundwater near the fault is enriched in CO(2) and, in some places, salinity is significantly elevated. In contrast, at the Springerville, Arizona site CO(2) is leaking upward through brine aquifers but does not appear to be increasing salinity in the shallow aquifer. Using multiphase transport simulations we show conditions under which significant CO(2) can be transported through deep brine aquifers into shallow layers. Only a subset of these conditions favor entrainment of salinity into the shallow aquifer: high aspect-ratio leakage pathways and viscous coupling between the fluid phases. Recognition of the conditions under which salinity is favored to be cotransported with CO(2) into shallow aquifers will be important in environmental risk assessments.

Groundwater circulation in deep carbonate regions

Science.gov (United States)

Szönyi-Mádl, Judit; Tóth, Ádám

2016-04-01

The operation of the subsurface part of the hydrologic cycle is hardly understood on basin scale due to the limitation in validated knowledge. Therefore the water balance approach is used with simplified numerical approaches during solving water related problems. The understanding of hierarchical nature of gravity-driven groundwater flow in near-surface and other driving forces in the deeper part of the lithosphere are often neglected. In this context thick and deep carbonate regions are especially less understood because the applicability of the gravity-driven regional groundwater flow (GDRGF) concept for such ranges formerly was debated. This is because karst studies are focused rather on the understanding of heterogeneity of karst systems. In contrary, this study found, on the basis of REV concept, that at regional scale not the local permeability values but its regional distribution is decisive. Firstly, according to the hydraulic diffusivity values it was stated that hydraulic connectivity is more effective in basinal carbonates compared to siliciclastics. Consequently, the efficient hydraulic responses for hydraulic head changes (due to water production or injection) in a carbonate system can give an indirect clue regarding hydraulic connectivity of the system rather than understanding the detailed permeability distribution. The concerns of the applicability of the GDRGF concept, therefore could be resolved. Subsequently, the concept of GDRGF can be used as a working hypothesis for understanding basinal hydraulics and geologic agency of flowing groundwater in thick carbonate ranges (Mádl-Szonyi and Tóth 2015). The hydrogeologically complex thick carbonate system of the Transdanubian Range (TR) Hungary was used as a study area to reveal the role of GDRGF at basin scale. Water level changes in the system, due to long-term mine dewatering exemplify the hydraulic continuity and compartmentalization of the system. Clustering of spring data, numerical flow and

Potential impacts of leakage from deep CO2 geosequestration on overlying freshwater aquifers.

Science.gov (United States)

Little, Mark G; Jackson, Robert B

2010-12-01

Carbon Capture and Storage may use deep saline aquifers for CO(2) sequestration, but small CO(2) leakage could pose a risk to overlying fresh groundwater. We performed laboratory incubations of CO(2) infiltration under oxidizing conditions for >300 days on samples from four freshwater aquifers to 1) understand how CO(2) leakage affects freshwater quality; 2) develop selection criteria for deep sequestration sites based on inorganic metal contamination caused by CO(2) leaks to shallow aquifers; and 3) identify geochemical signatures for early detection criteria. After exposure to CO(2), water pH declines of 1-2 units were apparent in all aquifer samples. CO(2) caused concentrations of the alkali and alkaline earths and manganese, cobalt, nickel, and iron to increase by more than 2 orders of magnitude. Potentially dangerous uranium and barium increased throughout the entire experiment in some samples. Solid-phase metal mobility, carbonate buffering capacity, and redox state in the shallow overlying aquifers influence the impact of CO(2) leakage and should be considered when selecting deep geosequestration sites. Manganese, iron, calcium, and pH could be used as geochemical markers of a CO(2) leak, as their concentrations increase within 2 weeks of exposure to CO(2).

An Overview of Geologic Carbon Sequestration Potential in California

Energy Technology Data Exchange (ETDEWEB)

Cameron Downey; John Clinkenbeard

2005-10-01

As part of the West Coast Regional Carbon Sequestration Partnership (WESTCARB), the California Geological Survey (CGS) conducted an assessment of geologic carbon sequestration potential in California. An inventory of sedimentary basins was screened for preliminary suitability for carbon sequestration. Criteria included porous and permeable strata, seals, and depth sufficient for critical state carbon dioxide (CO{sub 2}) injection. Of 104 basins inventoried, 27 met the criteria for further assessment. Petrophysical and fluid data from oil and gas reservoirs was used to characterize both saline aquifers and hydrocarbon reservoirs. Where available, well log or geophysical information was used to prepare basin-wide maps showing depth-to-basement and gross sand distribution. California's Cenozoic marine basins were determined to possess the most potential for geologic sequestration. These basins contain thick sedimentary sections, multiple saline aquifers and oil and gas reservoirs, widespread shale seals, and significant petrophysical data from oil and gas operations. Potential sequestration areas include the San Joaquin, Sacramento, Ventura, Los Angeles, and Eel River basins, followed by the smaller Salinas, La Honda, Cuyama, Livermore, Orinda, and Sonoma marine basins. California's terrestrial basins are generally too shallow for carbon sequestration. However, the Salton Trough and several smaller basins may offer opportunities for localized carbon sequestration.

Contribution of environmental isotopes to the study of large aquifers in Morocco

International Nuclear Information System (INIS)

Kabbaj, A.; Zeryouhi, I.; Carlier, P.

1978-01-01

The geochemistry of environmental isotopes has been applied to several aquifers in Maroc, some of them quite large: Charf el Akab in the Tanger region, the Oum er Rbia basin and the Tadla aquifer, the free nappe of limnic limes tone in the Sais plane, and the lias limestone aquifer. The isotopic investigations on the basis of hydrogeochemical data have given more precise information on the supply conditions of these aquifers. The types of water of different origin from the Atlas or the phosphate plateau in the Sais plane and the Tadla basin have been distinguished, the supply from one aquifer to another Lias nappe which, via the flexures of the Sais plane, supplies the nappe of limic limestone has been assessed, the homogeneity or heterogeneity of these aquifers has been investigated as well as their impermeability, the Tadla aquifer and the special case of Charf el Akab compared with the marine region. The findings have proved the usefulness of these techniques and permitted a specification of the general conditions for their application. (orig.) [de

The quality of our Nation's waters: water quality in the Mississippi embayment-Texas coastal uplands aquifer system and Mississippi River Valley alluvial aquifer, south-central United States, 1994-2008

Science.gov (United States)

Kingsbury, James A.; Barlow, Jeannie R.; Katz, Brian G.; Welch, Heather L.; Tollett, Roland W.; Fahlquist, Lynne S.

2015-01-01

About 8 million people rely on groundwater from the Mississippi embayment—Texas coastal uplands aquifer system for drinking water. The Mississippi River Valley alluvial aquifer also provides drinking water for domestic use in rural areas but is of primary importance to the region as a source of water for irrigation. Irrigation withdrawals from this aquifer are among the largest in the Nation and play a key role in the economy of the area, where annual crop sales total more than $7 billion. The reliance of the region on both aquifers for drinking water and irrigation highlights the importance of long-term management to sustain the availability and quality of these resources.

Comparative analysis of the evaluation of the intrinsic vulnerability in carbonate aquifers (Canete Mountain Range, province of Malaga); Analisis comparativo de la evaluacion de la vulnerabilidad intrinseca de acuiferos carbonaticos (Sierra de Canete, provincia de Malaga)

Energy Technology Data Exchange (ETDEWEB)

Jimenez Madrid, A.; Carrasco Cantos, F.; Martinez Navarrete, C.

2009-07-01

Groundwater of the carbonate aquifers of Canete Mountain Range constitute a basic source for water supply to different populations. Vulnerability intrinsic assesment is one of the most useful tools for the protection of the groundwater bodies, for this reason, this area has been chosen, to realize a comparative analysis, by means of the use of tools of spatial analysis and technical statistics of a Geographical Information System. In this work, Reduced DRASTIC, COP and RISK method have been applied, due to the fact that they are the methods used by Spain, both first ones, to evaluate the vulnerability of the groundwater bodies in the inter communal basins of the whole national territory, and for BRGM of France, the last one, to approach the carbonate aquifers protection. The obtained results show as the COP and RISK methods, specifics of carbonate aquifers, there show results more according to the characteristics of Canete Mountain Range that the obtained ones with Reduced DRASTIC, which unsaturated zone valuation causes an undervaluing the results of vulnerability obtained. (Author) 35 refs.

Chemical controls on abiotic and biotic release of geogenic arsenic from Pleistocene aquifer sediments to groundwater.

Science.gov (United States)

Gillispie, Elizabeth C; Andujar, Erika; Polizzotto, Matthew L

2016-08-10

Over 150 million people in South and Southeast Asia consume unsafe drinking water from arsenic-rich Holocene aquifers. Although use of As-free water from Pleistocene aquifers is a potential mitigation strategy, such aquifers are vulnerable to geogenic As pollution, placing millions more people at potential risk. The goal of this research was to define chemical controls on abiotic and biotic release of geogenic As to groundwater. Batch incubations of sediments with natural chemical variability from a Pleistocene aquifer in Cambodia were conducted to evaluate how interactions among arsenic, manganese and iron oxides, and dissolved and sedimentary organic carbon influenced As mobilization from sediments. The addition of labile dissolved organic carbon produced the highest concentrations of dissolved As after >7 months, as compared to sediment samples incubated with sodium azide or without added carbon, and the extent of As release was positively correlated with the percent of initial extractable Mn released from the sediments. The mode of As release was impacted by the source of DOC supplied to the sediments, with biological processes responsible for 81% to 85% of the total As release following incubations with lactate and acetate but only up to 43% to 61% of the total As release following incubations with humic and fulvic acids. Overall, cycling of key redox-active elements and organic-carbon reactivity govern the potential for geogenic As release to groundwater, and results here may be used to formulate better predictions of the arsenic pollution potential of aquifers in South and Southeast Asia.

Predicting the denitrification capacity of sandy aquifers from shorter-term incubation experiments and sediment properties

Directory of Open Access Journals (Sweden)

W. Eschenbach

2013-02-01

Full Text Available Knowledge about the spatial variability of denitrification rates and the lifetime of denitrification in nitrate-contaminated aquifers is crucial to predict the development of groundwater quality. Therefore, regression models were derived to estimate the measured cumulative denitrification of aquifer sediments after one year of incubation from initial denitrification rates and several sediment parameters, namely total sulphur, total organic carbon, extractable sulphate, extractable dissolved organic carbon, hot water soluble organic carbon and potassium permanganate labile organic carbon.

For this purpose, we incubated aquifer material from two sandy Pleistocene aquifers in Northern Germany under anaerobic conditions in the laboratory using the ¹⁵N tracer technique. The measured amount of denitrification ranged from 0.19 to 56.2 mg N kg⁻¹ yr⁻¹. The laboratory incubations exhibited high differences between non-sulphidic and sulphidic aquifer material in both aquifers with respect to all investigated sediment parameters. Denitrification rates and the estimated lifetime of denitrification were higher in the sulphidic samples. For these samples, the cumulative denitrification measured during one year of incubation (D_cum(365 exhibited distinct linear regressions with the stock of reduced compounds in the investigated aquifer samples. D_cum(365 was predictable from sediment variables within a range of uncertainty of 0.5 to 2 (calculated D_cum(365/measured D_cum(365 for aquifer material with a D_cum(365 > 20 mg N kg⁻¹ yr⁻¹. Predictions were poor for samples with lower D_cum(365, such as samples from the NO₃⁻ bearing groundwater zone, which includes the non-sulphidic samples, from the upper part of both aquifers where denitrification is not sufficient to

Analysis of fracturing in the basalts of the Serra Geral Aquifer and the potential regional recharge of the Guarani Aquifer System; Analise de fraturas dos basaltos do Aquifero Serra Geral e o potencial de recarga regional do Sistema Aquifero Guarani

Energy Technology Data Exchange (ETDEWEB)

Fernandes, A. J.; Assis Negri, F. de; Azevedo Sobrino, J. M.; Varnier, C.

2012-11-01

The Geological Institute, belonging to the Ministry for the Environment of the State of Sao Paulo, is currently undertaking regional research into vertical groundwater flow through the basalts in the Serra Geral Aquifer (ASG), which influences recharge of the sandstones in the underlying Guarani Aquifer System (SAG) and therefore the quantity of groundwater available and its susceptibility to pollution. The study area corresponds to the outcropping region of the ASG, an area of the state of Sao Paulo that contains important urban centres. The methods used included: (1) field work, focused on characterizing the vertical tectonic structures and the stresses responsible for their origin; and (2) an analysis of the structural data collected, aimed at identifying brittle tectonic events and their influence on groundwater flow. Distinguishing between cooling and tectonic fractures is a relevant aspect of the field work as only the tectonic events are capable of cutting across the vesicular beds, which otherwise form a barrier against vertical flow and block any connection between the aquifers. Three tectonic strike-slip events have been identified, each having generated hybrid tectonic fractures, which, because they involve extension as well as shearing, potentially favour flow. Diagnostic features suggest the occurrence in the south-western zone of the study area of preferential flow along fractures in the direction N70-80W and N60-80E, and secondary ones trending N20W and N20E; in the northeastern zone there is flow along secondary fractures in the direction N15W and N5-10E and in the central zone N40-65W. (Author)

Aquifers in coastal reclaimed lands - real world assessments

Science.gov (United States)

Saha, A.; Bironne, A.; Vonhögen-Peeters, L.; Lee, W. K.; Babovic, V. M.; Vermeulen, P.; van Baaren, E.; Karaoulis, M.; Blanchais, F.; Nguyen, M.; Pauw, P.; Doornenbal, P.

2017-12-01

Climate change and population growth are significant concerns in coastal regions around the world, where more than 30% of the world's population reside. The numbers continue to rise as coastal areas are increasingly urbanized. Urbanization creates land shortages along the coasts, which has spurred coastal reclamation activities as a viable solution. In this study, we focus on these reclamation areas; reclaimed areas in Singapore, and in the Netherlands, and investigate the potential of these reclaimed bodies as artificial aquifers that could attenuate water shortage problems in addition to their original purpose. We compare how the reclamation methods determine the hydrogeological characteristics of these manmade aquifers. We highlight similarities in freshwater lens development in the artificial shallow aquifers under natural recharge under diverse conditions, i.e. tropical and temperate zones, using numerical models. The characteristics and responses of these aquifers with dynamic freshwater-saltwater interface are contrasted against naturally occurring coastal aquifers where equilibrium was disturbed by anthropogenic activities. Finally, we assess the risks associated with subsidence and saltwater intrusion, combining measurements and numerical models, in case these aquifers are planned for Aquifer Storage and Recovery (ASR) or Managed Aquifer Recharge (MAR) strategies. Relative performances of some ASR schemes are simulated and compared in the reclaimed lands.

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

International Nuclear Information System (INIS)

Mullican, W.F. III; Fryar, A.E.; Johns, N.D.

1993-01-01

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 ft 2 /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

Economic efficiency and cost implications of habitat conservation: An example in the context of the Edwards Aquifer region

Science.gov (United States)

Gillig, Dhazn; McCarl, Bruce A.; Jones, Lonnie L.; Boadu, Frederick

2004-04-01

Groundwater management in the Edwards Aquifer in Texas is in the process of moving away from a traditional right of capture economic regime toward a more environmentally sensitive scheme designed to preserve endangered species habitats. This study explores economic and environmental implications of proposed groundwater management and water development strategies under a proposed regional Habitat Conservation Plan. Results show that enhancing the habitat by augmenting water flow costs $109-1427 per acre-foot and that regional water development would be accelerated by the more extreme possibilities under the Habitat Conservation Plan. The findings also indicate that a water market would improve regional welfare and lower water development but worsen environmental attributes.

Mapping the carbon footprint of EU regions

Science.gov (United States)

Ivanova, Diana; Vita, Gibran; Steen-Olsen, Kjartan; Stadler, Konstantin; Melo, Patricia C.; Wood, Richard; Hertwich, Edgar G.

2017-05-01

While the EU Commission has encouraged Member States to combine national and international climate change mitigation measures with subnational environmental policies, there has been little harmonized effort towards the quantification of embodied greenhouse gas (GHG) emissions from household consumption across European regions. This study develops an inventory of carbon footprints associated with household consumption for 177 regions in 27 EU countries, thus, making a key contribution for the incorporation of consumption-based accounting into local decision-making. Footprint calculations are based on consumer expenditure surveys and environmental and trade detail from the EXIOBASE 2.3 multiregional input-output database describing the world economy in 2007 at the detail of 43 countries, 5 rest-of-the-world regions and 200 product sectors. Our analysis highlights the spatial heterogeneity of embodied GHG emissions within multiregional countries with subnational ranges varying widely between 0.6 and 6.5 tCO2e/cap. The significant differences in regional contribution in terms of total and per capita emissions suggest notable differences with regards to climate change responsibility. The study further provides a breakdown of regional emissions by consumption categories (e.g. housing, mobility, food). In addition, our region-level study evaluates driving forces of carbon footprints through a set of socio-economic, geographic and technical factors. Income is singled out as the most important driver for a region’s carbon footprint, although its explanatory power varies significantly across consumption domains. Additional factors that stand out as important on the regional level include household size, urban-rural typology, level of education, expenditure patterns, temperature, resource availability and carbon intensity of the electricity mix. The lack of cross-national region-level studies has so far prevented analysts from drawing broader policy conclusions that hold

Estimating Aquifer Storage and Recovery (ASR Regional and Local Suitability: A Case Study in Washington State, USA

Directory of Open Access Journals (Sweden)

Maria T. Gibson

2018-01-01

Full Text Available Developing aquifers as underground water supply reservoirs is an advantageous approach applicable to meeting water management objectives. Aquifer storage and recovery (ASR is a direct injection and subsequent withdrawal technology that is used to increase water supply storage through injection wells. Due to site-specific hydrogeological quantification and evaluation to assess ASR suitability, limited methods have been developed to identify suitability on regional scales that are also applicable at local scales. This paper presents an ASR site scoring system developed to qualitatively assess regional and local suitability of ASR using 9 scored metrics to determine total percent of ASR suitability, partitioned into hydrogeologic properties, operational considerations, and regulatory influences. The development and application of a qualitative water well suitability method was used to assess the potential groundwater response to injection, estimate suitability based on predesignated injection rates, and provide cumulative approximation of statewide and local storage prospects. The two methods allowed for rapid assessment of ASR suitability and its applicability to regional and local water management objectives at over 280 locations within 62 watersheds in Washington, USA. It was determined that over 50% of locations evaluated are suitable for ASR and statewide injection potential equaled 6400 million liters per day. The results also indicate current limitations and/or potential benefits of developing ASR systems at the local level with the intent of assisting local water managers in strategic water supply planning.

Nonstationary porosity evolution in mixing zone in coastal carbonate aquifer using an alternative modeling approach.

Science.gov (United States)

Laabidi, Ezzeddine; Bouhlila, Rachida

2015-07-01

In the last few decades, hydrogeochemical problems have benefited from the strong interest in numerical modeling. One of the most recognized hydrogeochemical problems is the dissolution of the calcite in the mixing zone below limestone coastal aquifer. In many works, this problem has been modeled using a coupling algorithm between a density-dependent flow model and a geochemical model. A related difficulty is that, because of the high nonlinearity of the coupled set of equations, high computational effort is needed. During calcite dissolution, an increase in permeability can be identified, which can induce an increase in the penetration of the seawater into the aquifer. The majority of the previous studies used a fully coupled reactive transport model in order to model such problem. Romanov and Dreybrodt (J Hydrol 329:661-673, 2006) have used an alternative approach to quantify the porosity evolution in mixing zone below coastal carbonate aquifer at steady state. This approach is based on the analytic solution presented by Phillips (1991) in his book Flow and Reactions in Permeable Rock, which shows that it is possible to decouple the complex set of equation. This equation is proportional to the square of the salinity gradient, which can be calculated using a density driven flow code and to the reaction rate that can be calculated using a geochemical code. In this work, this equation is used in nonstationary step-by-step regime. At each time step, the quantity of the dissolved calcite is quantified, the change of porosity is calculated, and the permeability is updated. The reaction rate, which is the second derivate of the calcium equilibrium concentration in the equation, is calculated using the PHREEQC code (Parkhurst and Apello 1999). This result is used in GEODENS (Bouhlila 1999; Bouhlila and Laabidi 2008) to calculate change of the porosity after calculating the salinity gradient. For the next time step, the same protocol is used but using the updated porosity

Unsafe Practice of Extracting Potable Water From Aquifers in the Southwestern Coastal Region of Bangladesh

Science.gov (United States)

Chowdhury, S. H.; Ahmed, A. U.; Iqbal, M. Z.

2009-05-01

The groundwater resource is of paramount importance to the lives and livelihoods of the millions of people in Bangladesh. Unfortunately, high levels of arsenic have been found in groundwater in many parts of Bangladesh. Besides, the salinity in water systems in the coastal areas has increased as a consequence of the flow diversion from the upper reaches of Ganges River by the neighboring country India. Since hand- pumped groundwater (tube) wells are the only viable sources of drinking water, maintaining drinking water security for over 6 million people in the south-west (SW) region has been a major challenge for the Bangladesh Government. Due to rapid exploitation of groundwater resources in excess of recharge capacity, non-saline water sources in the SW region have already been depleted and the hand tube wells have mostly been abandoned. Meanwhile, shrimp farming has resulted in saline water infiltration into the perched aquifer system in many areas. A recent survey covering123 wells out of 184, extending to a depth of 330 m, showed high salinity in water. Combined factors of rapid exploitation of shallow groundwater, depletion of the deep aquifers and the subsequent saline water intrusion into these aquifers have put long-term sustainability of the remaining fresh groundwater resource into jeopardy. Very high concentrations of nitrite are found in this study in many tube wells in the area where samples have been drawn from aquifer systems up to 244 m deep. Nitrite concentrations in 35 wells randomly sampled in this study range from 16.98 to 43.11 mg/L, averaging 27.55 mg/L. This is much higher than the Maximum Contaminant Level (MCL) of 1 mg/L set by the U.S. EPA for human consumption. Simultaneously, dissolved oxygen (DO) is found to be very low (0.1 to 2 mg/L). There are numerous reports and anecdotal evidences of "Blue Baby Syndrome" (methemoglobinemia) in the region, which is generally due to gradual suffocation caused by poor transport of oxygen from the

Bioremediation of a diesel fuel contaminated aquifer: simulation studies in laboratory aquifer columns

Science.gov (United States)

Hess, A.; Höhener, P.; Hunkeler, D.; Zeyer, J.

1996-08-01

The in situ bioremediation of aquifers contaminated with petroleum hydrocarbons is commonly based on the infiltration of groundwater supplemented with oxidants (e.g., O 2, NO 3-) and nutrients (e.g., NH 4+, PO 43-). These additions stimulate the microbial activity in the aquifer and several field studies describing the resulting processes have been published. However, due to the heterogeneity of the subsurface and due to the limited number of observation wells usually available, these field data do not offer a sufficient spatial and temporal resolution. In this study, flow-through columns of 47-cm length equipped with 17 sampling ports were filled with homogeneously contaminated aquifer material from a diesel fuel contaminated in situ bioremediation site. The columns were operated over 96 days at 12°C with artificial groundwater supplemented with O 2, NO 3- and PO 43-. Concentration profiles of O 2, NO 3-, NO 2-, dissolved inorganic and organic carbon (DIC and DOC, respectively), protein, microbial cells and total residual hydrocarbons were measured. Within the first 12 cm, corresponding to a mean groundwater residence time of < 3.6 h, a steep O 2 decrease from 4.6 to < 0.3 mg l -1, denitrification, a production of DIC and DOC, high microbial cell numbers and a high removal of hydrocarbons were observed. Within a distance of 24 to 40.5 cm from the infiltration, O 2 was below 0.1 mg l -1 and a denitrifying activity was found. In the presence and in the absence of O 2, n-alkanes were preferentially degraded compared to branched alkanes. The results demonstrate that: (1) infiltration of aerobic groundwater into columns filled with aquifer material contaminated with hydrocarbons leads to a rapid depletion of O 2; (2) O 2 and NO 3- can serve as oxidants for the mineralization of hydrocarbons; and (3) the modelling of redox processes in aquifers has to consider denitrifying activity in presence of O 2.

Uranium Isotopes as a Tracer of Groundwater Evolution in the Complexe Terminal Aquifer of Southern Tunisia

Energy Technology Data Exchange (ETDEWEB)

Hadj Ammar, F. [Laboratory of Radio-Analysis and Environment, National School of Engineering of Sfax, Sfax (Tunisia); Centre Europeen de Recherche et d' Enseignement de Geosciences de l' Environnement, Aix en Provence (France); Deschamps, P.; Hamelin, B. [Centre Europeen de Recherche et d' Enseignement de Geosciences de l' Environnement, Aix en Provence (France); Chkir, N.; Zouari, K. [Laboratory of Radio-Analysis and Environment, National School of Engineering of Sfax, Sfax (Tunisia)

2013-07-15

The Complexe Terminal (CT) aquifer system is the main water supply for remote areas of southern Tunisia. Its exploitation has resulted in significant draw-down of the water table. The CT aquifer is a multilayered aquifer lodged in Miocene sand deposits, Senonian limestones and Turonian carbonates. Little is known about the relationships and exchanges between the different layers. Here, uranium isotopic measurements carried out in groundwater samples from the CT aquifer are presented in order to constrain models for mixing of water masses, water-rock interaction and groundwater flow. Analyses were performed using a VG54 (TIMS) at the CEREGE. Results indicate a range in {sup 238}U concentration and {sup 234}U/{sup 238}U activity ratios of 1.5 to 8 ppb and 1.1 to 3.2 respectively. Together with major and trace analyses, uranium isotopic compositions provide important insights into the factors controlling the chemical evolution of groundwater and shows very distinct patterns between carbonate and sandstone layers. (author)

Assessing Sea Level Rise Impacts on the Surficial Aquifer in the Kennedy Space Center Region

Science.gov (United States)

Xiao, H.; Wang, D.; Hagen, S. C.; Medeiros, S. C.; Warnock, A. M.; Hall, C. R.

2014-12-01

Global sea level rise in the past century due to climate change has been seen at an average rate of approximately 1.7-2.2 mm per year, with an increasing rate over the next century. The increasing SLR rate poses a severe threat to the low-lying land surface and the shallow groundwater system in the Kennedy Space Center in Florida, resulting in saltwater intrusion and groundwater induced flooding. A three-dimensional groundwater flow and salinity transport model is implemented to investigate and evaluate the extent of floods due to rising water table as well as saltwater intrusion. The SEAWAT model is chosen to solve the variable-density groundwater flow and salinity transport governing equations and simulate the regional-scale spatial and temporal evolution of groundwater level and chloride concentration. The horizontal resolution of the model is 50 m, and the vertical domain includes both the Surficial Aquifer and the Floridan Aquifer. The numerical model is calibrated based on the observed hydraulic head and chloride concentration. The potential impacts of sea level rise on saltwater intrusion and groundwater induced flooding are assessed under various sea level rise scenarios. Based on the simulation results, the potential landward movement of saltwater and freshwater fringe is projected. The existing water supply wells are examined overlaid with the projected salinity distribution map. The projected Surficial Aquifer water tables are overlaid with data of high resolution land surface elevation, land use and land cover, and infrastructure to assess the potential impacts of sea level rise. This study provides useful tools for decision making on ecosystem management, water supply planning, and facility management.

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

Science.gov (United States)

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

2018-01-01

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

Arsenic mobility in groundwater/surface water systems in carbonate-rich Pleistocene glacial drift aquifers (Michigan)

International Nuclear Information System (INIS)

Szramek, Kathryn; Walter, Lynn M.; McCall, Patti

2004-01-01

Within the Lower Peninsula of Michigan, groundwaters from the Marshall Formation (Mississippian) contain As derived from As-rich pyrites, often exceeding the World Heath Organization drinking water limit of 10 μg/L. Many Michigan watersheds, established on top of Pleistocene glacial drift derived from erosion of the underlying Marshall Formation, also have waters with elevated As. The Huron River watershed in southeastern Lower Michigan is a well characterized hydrogeochemical system of glacial drift deposits, proximate to the Marshall Fm. subcrop, which hosts carbonate-rich groundwaters, streams, and wetlands (fens), and well-developed soil profiles. Aqueous and solid phase geochemistry was determined for soils, soil waters, surface waters (streams and fens) and groundwaters from glacial drift aquifers to better understand the hydrogeologic and chemical controls on As mobility. Soil profiles established on the glacial drift exhibit enrichment in both Fe and As in the oxyhydroxide-rich zone of accumulation. The amounts of Fe and As present as oxyhydroxides are comparable to those reported from bulk Marshall Fm. core samples by previous workers. However, the As host in core samples is largely unaltered pyrite and arsenopyrite. This suggests that the transformation of Fe sulfides to Fe oxyhydroxides largely retains As and Fe at the oxidative weathering site. Groundwaters have the highest As values of all the waters sampled, and many were at or above the World Health limit. Most groundwaters are anaerobic, within the zones of Fe 3+ and As(V) reduction. Although reduction of Fe(III) oxyhydroxides is the probable source of As, there is no correlation between As and Fe concentrations. The As/Fe mole ratios in drift groundwaters are about an order of magnitude greater than those in soil profiles, suggesting that As is more mobile than Fe. This is consistent with the dominance of As(III) in these groundwaters and with the partitioning of Fe 2+ into carbonate cements. Soil

Interpretation of Flow Logs from Nevada Test Site Boreholes to Estimate Hydraulic Conductivity Using Numerical Simulations Constrained by Single-Well Aquifer Tests

Science.gov (United States)

Garcia, C. Amanda; Halford, Keith J.; Laczniak, Randell J.

2010-01-01

Hydraulic conductivities of volcanic and carbonate lithologic units at the Nevada Test Site were estimated from flow logs and aquifer-test data. Borehole flow and drawdown were integrated and interpreted using a radial, axisymmetric flow model, AnalyzeHOLE. This integrated approach is used because complex well completions and heterogeneous aquifers and confining units produce vertical flow in the annular space and aquifers adjacent to the wellbore. AnalyzeHOLE simulates vertical flow, in addition to horizontal flow, which accounts for converging flow toward screen ends and diverging flow toward transmissive intervals. Simulated aquifers and confining units uniformly are subdivided by depth into intervals in which the hydraulic conductivity is estimated with the Parameter ESTimation (PEST) software. Between 50 and 150 hydraulic-conductivity parameters were estimated by minimizing weighted differences between simulated and measured flow and drawdown. Transmissivity estimates from single-well or multiple-well aquifer tests were used to constrain estimates of hydraulic conductivity. The distribution of hydraulic conductivity within each lithology had a minimum variance because estimates were constrained with Tikhonov regularization. AnalyzeHOLE simulated hydraulic-conductivity estimates for lithologic units across screened and cased intervals are as much as 100 times less than those estimated using proportional flow-log analyses applied across screened intervals only. Smaller estimates of hydraulic conductivity for individual lithologic units are simulated because sections of the unit behind cased intervals of the wellbore are not assumed to be impermeable, and therefore, can contribute flow to the wellbore. Simulated hydraulic-conductivity estimates vary by more than three orders of magnitude across a lithologic unit, indicating a high degree of heterogeneity in volcanic and carbonate-rock units. The higher water transmitting potential of carbonate-rock units relative

Interpretation of Flow Logs from Nevada Test Site Boreholes to Estimate Hydraulic conductivity Using Numerical Simulations Constrained by Single-Well Aquifer Tests

Energy Technology Data Exchange (ETDEWEB)

Garcia, C. Amanda; Halford, Keith J.; Laczniak, Randell J.

2010-02-12

Hydraulic conductivities of volcanic and carbonate lithologic units at the Nevada Test Site were estimated from flow logs and aquifer-test data. Borehole flow and drawdown were integrated and interpreted using a radial, axisymmetric flow model, AnalyzeHOLE. This integrated approach is used because complex well completions and heterogeneous aquifers and confining units produce vertical flow in the annular space and aquifers adjacent to the wellbore. AnalyzeHOLE simulates vertical flow, in addition to horizontal flow, which accounts for converging flow toward screen ends and diverging flow toward transmissive intervals. Simulated aquifers and confining units uniformly are subdivided by depth into intervals in which the hydraulic conductivity is estimated with the Parameter ESTimation (PEST) software. Between 50 and 150 hydraulic-conductivity parameters were estimated by minimizing weighted differences between simulated and measured flow and drawdown. Transmissivity estimates from single-well or multiple-well aquifer tests were used to constrain estimates of hydraulic conductivity. The distribution of hydraulic conductivity within each lithology had a minimum variance because estimates were constrained with Tikhonov regularization. AnalyzeHOLE simulated hydraulic-conductivity estimates for lithologic units across screened and cased intervals are as much as 100 times less than those estimated using proportional flow-log analyses applied across screened intervals only. Smaller estimates of hydraulic conductivity for individual lithologic units are simulated because sections of the unit behind cased intervals of the wellbore are not assumed to be impermeable, and therefore, can contribute flow to the wellbore. Simulated hydraulic-conductivity estimates vary by more than three orders of magnitude across a lithologic unit, indicating a high degree of heterogeneity in volcanic and carbonate-rock units. The higher water transmitting potential of carbonate-rock units relative

Flow of river water into a karstic limestone aquifer - 2. Dating the young fraction in groundwater mixtures in the Upper Floridan aquifer near Valdosta, Georgia

Science.gov (United States)

Plummer, Niel; Busenberg, E.; Drenkard, S.; Schlosser, P.; Ekwurzel, B.; Weppernig, R.; McConnell, J.B.; Michel, R.L.

1998-01-01

Tritium/helium-3 (3H/3He) and chlorofluorocarbon (CFCs, CFC-11, CFC-12, CFC-113) data are used to date the young fraction in groundwater mixtures from a karstic limestone aquifer near Valdosta, Georgia, where regional paleowater in the Upper Floridan aquifer receives recharge from two young sources the flow of Withlacoochee River water through sinkholes in the river bed, and leakage of infiltration water through post-Eocene semi-confining beds above the Upper Floridan aquifer. In dating the young fraction of mixtures using CFCs, it is necessary to reconstruct the CFC concentration that was in the young fraction prior to mixing. The 3H/3He age is independent of the extent of dilution with older (3H-free and 3He(trit)-free) water. The groundwater mixtures are designated as Type-I for mixtures of regional paleowater and regional infiltration water and Type-2 for mixtures containing more than approximately 4% of river water. The fractions of regional paleowater, regional infiltration water, and Withlacoochee River water in the groundwater mixtures were determined from Cl- and ??18O data for water from the Upper Floridan aquifer at Valdosta, Georgia The chlorofluorocarbons CFC-11 and CFC-113 are removed by microbial degradation and/or sorption processes in most allaerobic (Type-2) groundwater at Valdosta, but are present in some aerobic Type-I water. CFC-12 persists in both SO4-reducing and methanogenic water. The very low detection limits for CFCs (approximately 0.3 pg kg-1) permitted CFC-11 and CFC-12 dating of the fraction of regional infiltration water in Type-I mixtures, and CFC-12 dating of the river-water fraction in Type-2 mixtures. Overall, approximately 50% of the 85 water sam pies obtained from the Upper Floridan aquifer have CFC-12-based ages of the young traction that are consistent with the 3H concentration of the groundwater. Because of uncertainties associated with very low 3H and 3He content in dilute mixtures, 3H/3He dating is limited to the river

Hydrochemistry of New Zealand's aquifers

International Nuclear Information System (INIS)

Rosen, M.R.

2001-01-01

Groundwater chemistry on a national scale has never been studied in New Zealand apart from a few studies on nitrate concentrations and pesticides. These studies are covered in Chapter 8 of this book. However general studies of groundwater chemistry, groundwater-rock interaction and regional characteristics of water quality have not been previously addressed in much detail. This is partly because New Zealand aquifers are relatively small on a world scale and are geologically and tectonically diverse (see Chapter 3). But New Zealand has also recently lacked a centralised agency responsible for groundwater quality, and therefore, no national assessments have been undertaken. In recent years, the Institute of Geological and Nuclear Sciences has managed a programme of collecting and analysing the groundwater chemistry of key New Zealand aquifers. This programme is called the National Groundwater Monitoring Programme (NGMP) and is funded by the New Zealand Public Good Science Fund. The programme started in 1990 using only 22 wells, with four regional authorities of the country participating. The NGMP now includes all 15 regional and unitary authorities that use groundwater and over 100 monitoring sites. The NGMP is considered a nationally significant database by the New Zealand Foundation for Research Science and Technology. The NGMP allows a national comparison of aquifer chemistries because the samples are all analysed at one laboratory in a consistent manner and undergo stringent quality control checks. Poor quality analyses are thus minimised. In addition, samples are collected quarterly so that long-term seasonal trends in water quality can be analysed, and the effects of changes in land use and the vulnerability of aquifers to contaminant leaching can be assessed. This chapter summarises the water quality data collected for the NGMP over the past 10 years. Some records are much shorter than others, but most are greater than three years. Additional information is

Water-quality characteristics of quaternary unconsolidated-deposit aquifers and lower tertiary aquifers of the Bighorn Basin, Wyoming and Montana, 1999-2001

Science.gov (United States)

Bartos, Timothy T.; Eddy-Miller, Cheryl A.; Norris, Jody R.; Gamper, Merry E.; Hallberg, Laura L.

2004-01-01

As part of the Yellowstone River Basin National Water Quality Assessment study, ground-water samples were collected from Quaternary unconsolidated-deposit and lower Tertiary aquifers in the Bighorn Basin of Wyoming and Montana from 1999 to 2001. Samples from 54 wells were analyzed for physical characteristics, major ions, trace elements, nutrients, dissolved organic carbon, radionuclides, pesticide compounds, and volatile organic compounds (VOCs) to evaluate current water-quality conditions in both aquifers. Water-quality samples indicated that waters generally were suitable for most uses, and that natural conditions, rather than the effects of human activities, were more likely to limit uses of the waters. Waters in both types of aquifers generally were highly mineralized, and total dissolved-solids concentrations frequently exceeded the U.S. Environmental Protection Agency (USEPA) Secondary Maximum Contaminant Level (SMCL) of 500 milligrams per liter (mg/L). Because of generally high mineralization, waters from nearly one-half of the samples from Quaternary aquifers and more than one-half of the samples from lower Tertiary aquifers were not classified as fresh (dissolved-solids concentration were not less than 1,000 mg/L). The anions sulfate, fluoride, and chloride were measured in some ground-water samples at concentrations greater than SMCLs. Most waters from the Quaternary aquifers were classified as very hard (hardness greater than 180 mg/L), but hardness varied much more in waters from the lower Tertiary aquifers and ranged from soft (less than 60 mg/L) to very hard (greater than 180 mg/L). Major-ion chemistry varied with dissolved-solids concentrations. In both types of aquifers, the predominant anion changes from bicarbonate to sulfate with increasing dissolved-solids concentrations. Samples from Quaternary aquifers with fresh waters generally were calcium-bicarbonate, calcium-sodium-bicarbonate, and calcium-sodium-sulfate-bicarbonate type waters, whereas

Pesticide sorption by low organic carbon sediments: A sceening for seven herbicides

DEFF Research Database (Denmark)

Madsen, Lene; Lindhardt, Bo; Rosenberg, Per

2000-01-01

The sorption of seven pesticides in 10 Danish aquifer sediments has been studied. These sediments all have a total organic carbon (TOC) content below 1 g kg(-1), and include carbonate-bearing and carbonate-free Quatenary sand deposits and a Cretaceous chalk aquifer. Batch experiments were carried...

Southeast Regional Carbon Sequestration Partnership (SECARB)

Energy Technology Data Exchange (ETDEWEB)

Kenneth J. Nemeth

2005-09-30

The Southeast Regional Carbon Sequestration Partnership (SECARB) is a diverse partnership covering eleven states involving the Southern States Energy Board (SSEB) an interstate compact; regulatory agencies and/or geological surveys from member states; the Electric Power Research Institute (EPRI); academic institutions; a Native American enterprise; and multiple entities from the private sector. Figure 1 shows the team structure for the partnership. In addition to the Technical Team, the Technology Coalition, an alliance of auxiliary participants, in the project lends yet more strength and support to the project. The Technology Coalition, with its diverse representation of various sectors, is integral to the technical information transfer, outreach, and public perception activities of the partnership. The Technology Coalition members, shown in Figure 2, also provide a breadth of knowledge and capabilities in the multiplicity of technologies needed to assure a successful outcome to the project and serve as an extremely important asset to the partnership. The eleven states comprising the multi-state region are: Alabama; Arkansas; Florida; Georgia; Louisiana; Mississippi; North Carolina; South Carolina; Tennessee; Texas; and Virginia. The states making up the SECARB area are illustrated in Figure 3. The primary objectives of the SECARB project include: (1) Supporting the U.S. Department of Energy (DOE) Carbon Sequestration Program by promoting the development of a framework and infrastructure necessary for the validation and deployment of carbon sequestration technologies. This requires the development of relevant data to reduce the uncertainties and risks that are barriers to sequestration, especially for geologic storage in the SECARB region. Information and knowledge are the keys to establishing a regional carbon dioxide (CO{sub 2}) storage industry with public acceptance. (2) Supporting the President's Global Climate Change Initiative with the goal of reducing

Yield and quality of ground water from stratified-drift aquifers, Taunton River basin, Massachusetts : executive summary

Science.gov (United States)

Lapham, Wayne W.; Olimpio, Julio C.

1989-01-01

Water shortages are a chronic problem in parts of the Taunton River basin and are caused by a combination of factors. Water use in this part of the Boston metropolitan area is likely to increase during the next decade. The Massachusetts Division of Water Resources projects that about 50% of the cities and towns within and on the perimeter of the basin may have water supply deficits by 1990 if water management projects are not pursued throughout the 1980s. Estimates of the long-term yield of the 26 regional aquifers indicate that the yields of the two most productive aquifers equal or exceed 11.9 and 11.3 cu ft/sec, 90% of the time, respectively, if minimum stream discharge is maintained at 99.5% flow duration. Eighteen of the 26 aquifers were pumped for public water supply during 1983. Further analysis of the yield characteristics of these 18 aquifers indicates that the 1983 pumping rate of each of these 18 aquifers can be sustained at least 70% of the time. Selected physical properties and concentrations of major chemical constituents in groundwater from the stratified-drift aquifers at 80 sampling sites were used to characterize general water quality in aquifers throughout the basin. The pH of the groundwater ranged from 5.4 to 7.0. Natural elevated concentrations of Fe and Mn in water in the stratified-drift aquifers are present locally in the basin. Natural concentrations of these two metals commonly exceed the limits of 0.3 mg/L for Fe and 0.05 mg/L for Mn recommended for drinking water. Fifty-one analyses of selected trace metals in groundwater samples from stratified-drift aquifers throughout the basin were used to characterize trace metal concentrations in the groundwater. Of the 10 constituents sampled that have US EPA limits recommended for drinking water, only the Pb concentration in water at one site (60 micrograms/L) exceeded the recommended limit of 50 micrograms/L. Analyses of selected organic compounds in water in the stratified-drift aquifers at 74

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.

Radiocarbon ages of ground water as a basis for the determination of safe limits of aquifer exploitation

International Nuclear Information System (INIS)

Tamers, M.A.; Stipp, J.J.; Weiner, R.

1975-01-01

Deep ground waters of the Biscayne aquifer of south Florida were studied with radiocarbon dating techniques. Dissolved carbonates served as the material for the age determinations. Limestone dilution corrections of the measured carbon-14 activities were made by comparison of the relative concentrations of bicarbonate and total carbonates. The deep well waters of the southern portion of the deposit have corrected radiocarbon contents indicating thermonuclear weapon testing contamination; they are, therefore, less than 20 years old. The ages of the ground waters generally increase in the northern direction. This is interpreted as due to the greater depth of the deposit of that region. A model is formulated for ground water movement in an unconfined producing hydrological unit and applied to the radiocarbon results of the most intensively exploited zone of the Biscayne aquifer. It is shown that the water which is extracted by the municipal wells in this area is limited to the bottom third of the deposit. The avoidance of pollution from the surrounding septic tanks in the shallower depths of the area is explained in this way. The model leads to an objective estimation of the safe limit for the ground water extraction rate in the zone. By application of radiocarbon dating, it is possible to obtain useful information without disturbing the water supply

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

Science.gov (United States)

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

2011-01-01

capita water use for exempt wells. Accuracy of the simulated groundwater-flow system was evaluated by using observational control from water levels in wells, estimates of base flow from streamflow records, and estimates of spring discharge. Major results from the simulations include the importance of variations in recharge rates throughout the study area and recharge along ephemeral and losing stream reaches in alluvial basins. Insights about the groundwater-flow systems in individual basins include the hydrologic influence of geologic structures in some areas and that stream-aquifer interactions along the lower part of the Little Colorado River are an effective control on water level distributions throughout the Little Colorado River Plateau basin. Better information on several aspects of the groundwater flow system are needed to reduce uncertainty of the simulated system. Many areas lack documentation of the response of the groundwater system to changes in withdrawals and recharge. Data needed to define groundwater flow between vertically adjacent water-bearing units is lacking in many areas. Distributions of recharge along losing stream reaches are poorly defined. Extents of aquifers and alluvial lithologies are poorly defined in parts of the Big Chino and Verde Valley sub-basins. Aquifer storage properties are poorly defined throughout most of the study area. Little data exist to define the hydrologic importance of geologic structures such as faults and fractures. Discharge of regional groundwater flow to the Verde River is difficult to identify in the Verde Valley sub-basin because of unknown contributions from deep percolation of excess surface water irrigation.

Preliminary Analysis of the Role of Wetlands and Rivers in the Groundwater Discharge of the Guarani Aquifer System in NE Argentina

Energy Technology Data Exchange (ETDEWEB)

Vives, L., E-mail: lvives@faa.unicen.edu.ar [Instituto de Hidrologia de Llanuras, Universidad Nacional del Centro de la Provincia de Buenos Aires, Azul (Argentina); Rodriguez, L. [Centro de Estudios Hidroambientales, Facultad de Ingenieria y Ciencias Hidricas, Universidad Nacional del Litoral, Santa Fe (Argentina); Manzano, M. [Escuela de Ingenieria de Caminos y de Minas, Universidad Politecnica de Cartagena, Cartagena (Spain); Valladares, A. [Subsecretaria de Recursos Hidricos (Argentina); Aggarwal, P. K.; Araguas Araguas, L. [International Atomic Energy Angency, Vienna (Austria)

2013-07-15

The Guarani Aquifer System (GAS) is the largest aquifer in South America. Previous regional hydrochemical and isotopic studies suggested that discharge may occur at wetlands and reaches of the Parana and Uruguay Rivers. Preliminary findings of a project aimed at verifying the discharge hypothesis on the southern GAS region are presented. The hydrochemical- isotopic composition of 17 samples from surface and groundwater in that area were analysed. Some waters showed chemical facies and isotopic (stable isotope and carbon-14) signatures similar to the formerly identified as GAS+pre-GAS formations. Admixtures between modern and GAS+pre-GAS waters were found at depths between less than 100 m and 200 m. A 96 m deep well located near the Ibera lagoon showed chemical and isotopic composition indicating presence of GAS waters. The hydraulic gradient favours upward flow near the wetlands, but surface waters seem to originate from local recharge. Investigations continue, incorporating {sup 222}Rn and new sampling sites. (author)

Groundwater geochemistry of a Mio-Pliocene aquifer in the northeastern Algerian Sahara (Djamaa region)

Science.gov (United States)

Houari, Idir Menad; Nezli, Imed Eddine; Belksier, Mohamed Salah

2018-05-01

The groundwater resources in the Northern Sahara are represented by two superimposed major aquifer systems: the Intercalary Continental (CI) and the Terminal Complex (CT). The waters of these aquifers pose serious physical and chemical quality problems; they are highly mineralized and very hard. The present work aims to describe the water's geochemical evolution of sand groundwater (Mio-Pliocene) of the Terminal Complex in the area of Djamaa, by the research of the relationship between water's chemical composition and lithology of aquifer formations through. The results obtained show that the water's chemistry is essentially governed by the dissolution of evaporate formations, which gives to, waters an excessive mineralization expressed by high concentrations of sulfates, chlorides and sodium.

SRP baseline hydrogeologic investigation: Aquifer characterization

Energy Technology Data Exchange (ETDEWEB)

Strom, R.N.; Kaback, D.S.

1992-03-31

An investigation of the mineralogy and chemistry of the principal hydrogeologic units and the geochemistry of the water in the principal aquifers at Savannah River Site (SRS) was undertaken as part of the Baseline Hydrogeologic Investigation. This investigation was conducted to provide background data for future site studies and reports and to provide a site-wide interpretation of the geology and geochemistry of the Coastal Plain Hydrostratigraphic province. Ground water samples were analyzed for major cations and anions, minor and trace elements, gross alpha and beta, tritium, stable isotopes of hydrogen, oxygen, and carbon, and carbon-14. Sediments from the well borings were analyzed for mineralogy and major and minor elements.

Natural dissolved organic matter dynamics in karstic aquifer: O'Leno Sink-Rise system, Florida, USA

Science.gov (United States)

Jin, J.; Zimmerman, A. R.

2010-12-01

Natural dissolved organic matter (NDOM) dynamics in karstic aquifer remain poorly understood due to the inaccessibility and heterogeneity of the subsurface. Because the Santa Fe River sinks into the Floridan Aquifer and emerges 6 km down gradient, the O'Leno Sink-Rise system in Northern Florida provides an ideal setting to study NDOM transformation in groundwater. Water samples were collected at both high and low temporal resolutions over 3 years from the River Sink, Rise, and a series of shallow and deep wells. Analyses of dissolved organic and inorganic carbon, stable isotopic, and spectrophotometry (excitation-emission matrix or EEM) show that reversals of hydrologic head gradient in the conduit and matrix are closely related to the delivery of NDOM to the aquifer. In addition, the relative influence of biotic and abiotic processes varies along spatiotemporal gradients; regions of the aquifer with greatest connectivity to surface water (new NDOM and terminal electron acceptor supply) see the most microbial transformation of NDOM, while those with least connectivity see relatively greater abiotic transformation of NDOM. A source water mixing model was established for the Sink-Rise system using Mg2+ and SO42- concentrations from three end-members identified as allogenic recharge, upwelling deep water, and shallow groundwater of the Upper Floridan Aquifer. Biogeochemical processes were quantified after accounting for changes that occurred due to source water mixing, according to the model. In addition to NDOM remineralization by subsurface microbes which occurred mostly during wet periods, adsorption of NDOM onto aquifer materials as well as release of NDOM from aquifer materials was also observed. During wet periods when DOC-rich conduit water entered the matrix, progressive NDOM remineralization was found along the preferential flow paths from the conduits into the matrices. Both biotic and abiotic NDOM transformation processes were found to control channel

Quality of Waters of Aquifer Webs of Biskra Region | Bouchemal ...

African Journals Online (AJOL)

Controlling the quality of water distributed together with sound resource management is a factor of economic and social development. Also, the chemistry and knowledge of geological and hydrogeological aquifer, the object of this work, we identify the water quality examined through physical-chemical parameters. The study ...

Southwest Regional Partnership on Carbon Sequestration

Energy Technology Data Exchange (ETDEWEB)

Brian McPherson

2006-03-31

The Southwest Partnership on Carbon Sequestration completed its Phase I program in December 2005. The main objective of the Southwest Partnership Phase I project was to evaluate and demonstrate the means for achieving an 18% reduction in carbon intensity by 2012. Many other goals were accomplished on the way to this objective, including (1) analysis of CO{sub 2} storage options in the region, including characterization of storage capacities and transportation options, (2) analysis and summary of CO{sub 2} sources, (3) analysis and summary of CO{sub 2} separation and capture technologies employed in the region, (4) evaluation and ranking of the most appropriate sequestration technologies for capture and storage of CO{sub 2} in the Southwest Region, (5) dissemination of existing regulatory/permitting requirements, and (6) assessing and initiating public knowledge and acceptance of possible sequestration approaches. Results of the Southwest Partnership's Phase I evaluation suggested that the most convenient and practical ''first opportunities'' for sequestration would lie along existing CO{sub 2} pipelines in the region. Action plans for six Phase II validation tests in the region were developed, with a portfolio that includes four geologic pilot tests distributed among Utah, New Mexico, and Texas. The Partnership will also conduct a regional terrestrial sequestration pilot program focusing on improved terrestrial MMV methods and reporting approaches specific for the Southwest region. The sixth and final validation test consists of a local-scale terrestrial pilot involving restoration of riparian lands for sequestration purposes. The validation test will use desalinated waters produced from one of the geologic pilot tests. The Southwest Regional Partnership comprises a large, diverse group of expert organizations and individuals specializing in carbon sequestration science and engineering, as well as public policy and outreach. These partners

Hydrochemistry and isotope geochemistry as management tools for groundwater resources in multilayer aquifers: A study case from the Po plain (Lomellina, South-Western Lombardy, Italy)

Energy Technology Data Exchange (ETDEWEB)

Pilla, G; Sacchi, E; Ciancetti, G; Braga, G [Dipartimento di Scienze della Terra, Universita di Pavia, Pavia (Italy); Zuppi, G M [Dipartimento di Scienze Ambientali, Universita Ca' Foscari di Venezia, Venice (Italy)

2003-07-01

distinguished. All data were georeferenced and integrated in a GIS database. Subsequently, 40 wells and natural outflows were selected for the hydrochemical and isotopic characterisation. The selection was performed in order to cover homogeneously the studied region both in terms of extension and depth. Analyses included major ions, trace elements, pesticides, stable isotopes of the water molecule, {sup 13}C and {sup 14}C of dissolved inorganic carbon. Shallow waters containing high levels of nitrates were considered for the isotopic analysis of {sup 15}N and {sup 18}O of NO{sub 3}{sup -}. Hydrochemical analyses defined the hydrochemical facies as calcium-bicarbonate. Groundwaters generally show a decreasing conductivity and mineralisation with depth. The phreatic aquifer displays evidence for groundwater pollution from agricultural activities, namely high nitrate, sulphate and chloride contents and, locally, detectable levels of pesticides. Deep confined aquifers contain groundwater of excellent quality standards. Activity diagrams clearly allow the distinction between the phreatic aquifer and the confined aquifers, which display a higher degree of interaction with the aquifer matrix. Stable isotopes of the water molecule are in agreement with the results form adjacent sectors of the Po plain (Pilla, 1998), evidencing the lateral continuity of the aquifers. The phreatic aquifer and the different confined aquifers may be distinguished on the basis of their isotopic composition, which also allowed to verify their hydraulic confinement of deeper aquifers. Intermediate aquifers are in part recharged by the shallow phreatic aquifer, which in turn is fed by local infiltration and by streams and irrigation channels. The isotopic analysis of nitrates of 10 waters samples from outflows and shallow wells confirms the agricultural origin of contaminants in the phreatic aquifer. The isotopic signature is typical for the nitrification of synthetic fertilisers (Clark and Fritz, 1997). A

Hydrology of aquifer systems in the Memphis area, Tennessee

Science.gov (United States)

Criner, James H.; Sun, P-C. P.; Nyman, Dale J.

1964-01-01

. The average rate of depletion of storage in each aquifer since pumping began is about 1 mgd. Most of the recharge to the '500-foot' and '1,400-foot' sands occurs in outcrop areas about 30-80 miles east of Memphis. Also, water leaks from the terrace deposits to the '500-foot' sand in some places, and there may be some leakage from streams where the confining clay is thin or is breached by faults or streams. The quality of water from both the principal aquifers is very good. Iron, carbon dioxide, and hydrogen sulfide are the only constituents found in undesirable quantities. Water from the terrace deposits is hard but generally contains less iron and carbon dioxide than water from either of the principal aquifers. The hydraulic characteristics of both aquifers were determined by pumping tests and by applying the knowledge of the geology o# the area; these characteristics indicate that the aquifers are capable of producing more water than is currently being pumped from them. The '500-foot' sand will produce more water per unit decline of water level than will the '1,400-foot' sand. There appears to be no reason why the development of water supplies from both aquifers should not continue, but well spacing will remain a factor which could affect future development. Greater well spacing will tend to prolong the useful life of a well and the aquifers.

AQUIFER OF THE WESTERN PART OF THE PRGOVO POLJE ON THE ISLAND OF LASTOVO

Directory of Open Access Journals (Sweden)

Renato Buljan

2006-12-01

Full Text Available Two new-drilled wells in the Prgovo Polje are pumped and additionally tested for the water supply of the island Lastovo. The research works were aimed at finding boundary quantitative and qualitative parameters for their optimal exploitation, desalination and use of the pumped water in the existent water supply system. Collected hydrogeological and hydrogeochemical data indicate the presence of stratified aquifer in the western part of Prgovo Polje consisting of two poorly connected horizons. Water from the shallower part of the aquifer, drilled by the well MZ-2 in the carbonate rocks at the edge of polje, is good enough for desalination. The deeper part of aquifer, drilled by the well MZ-1 in the carbonate cavern below the polje’s clastic sediments, experiences the greater influence of the sea water. Its continuing pumping combined with low quantity of water is the main reason of the ever increasing influence of the sea water (the paper is published in Croatian.

Aquifer restoration at uranium in situ leach sites

International Nuclear Information System (INIS)

Anastasi, F.S.; Williams, R.E.

1985-01-01

In situ mining of uranium involves injection of a leaching solution (lixiviant) into an ore-bearing aquifer. Frequently, the ground water in the mined aquifer is a domestic or livestock water supply. As the lixiviant migrates through the ore body, uranium and various associated elements such as arsenic, selenium, molybdenum, vanadium and radium-226 are mobilized in the ground water. Aquifer restoration after in situ mining is not fully understood. Several methods have been developed to restore mined aquifers to pre-mining (baseline) quality. Commonly used methods include ground water sweeping, clean water injection, and treatment by ion exchange and reverse osmosis technologies. Ammonium carbonate lixiviant was used at one RandD in situ mine. Attempts were made to restore the aquifer using a variety of methods. Efforts were successful in reducing concentrations of the majority of contaminants to baseline levels. Concentrations of certain parameters, however, remained at levels above baseline six months after restoration ceased. Relatively large quantities of ground water were processed in the restoration attempt considering the small size of the project (1.25 acre). More thorough characterization of the hydrogeology of the site may have enhanced the effectiveness of restoration and reduced potential environmental impacts associated with the project. This paper presents some of the findings of a research project conducted by the Mineral Resources Waste Management Team at the University of Idaho in Moscow, Idaho. Views contained herein do not reflect U.S. Nuclear Regulatory Commission policy

Sources of high-chloride water and managed aquifer recharge in an alluvial aquifer in California, USA

Science.gov (United States)

O'Leary, David R.; Izbicki, John A.; Metzger, Loren F.

2015-11-01

As a result of pumping in excess of recharge, water levels in alluvial aquifers within the Eastern San Joaquin Groundwater Subbasin, 130 km east of San Francisco (California, USA), declined below sea level in the early 1950s and have remained so to the present. Chloride concentrations in some wells increased during that time and exceeded the US Environmental Protection Agency's secondary maximum contaminant level of 250 mg/L, resulting in removal of some wells from service. Sources of high-chloride water include irrigation return in 16 % of sampled wells and water from delta sediments and deeper groundwater in 50 % of sampled wells. Chloride concentrations resulting from irrigation return commonly did not exceed 100 mg/L, although nitrate concentrations were as high as 25 mg/L as nitrogen. Chloride concentrations ranged from less than 100-2,050 mg/L in wells affected by water from delta sediments and deeper groundwater. Sequential electromagnetic logs show movement of high-chloride water from delta sediments to pumping wells through permeable interconnected aquifer layers. δD and δ18O data show most groundwater originated as recharge along the front of the Sierra Nevada, but tritium and carbon-14 data suggest recharge rates in this area are low and have decreased over recent geologic time. Managed aquifer recharge at two sites show differences in water-level responses to recharge and in the physical movement of recharged water with depth related to subsurface geology. Well-bore flow logs also show rapid movement of water from recharge sites through permeable interconnected aquifer layers to pumping wells.

Sources of high-chloride water and managed aquifer recharge in an alluvial aquifer in California, USA

Science.gov (United States)

O'Leary, David; Izbicki, John A.; Metzger, Loren F.

2015-01-01

As a result of pumping in excess of recharge, water levels in alluvial aquifers within the Eastern San Joaquin Groundwater Subbasin, 130 km east of San Francisco (California, USA), declined below sea level in the early 1950s and have remained so to the present. Chloride concentrations in some wells increased during that time and exceeded the US Environmental Protection Agency’s secondary maximum contaminant level of 250 mg/L, resulting in removal of some wells from service. Sources of high-chloride water include irrigation return in 16 % of sampled wells and water from delta sediments and deeper groundwater in 50 % of sampled wells. Chloride concentrations resulting from irrigation return commonly did not exceed 100 mg/L, although nitrate concentrations were as high as 25 mg/L as nitrogen. Chloride concentrations ranged from less than 100–2,050 mg/L in wells affected by water from delta sediments and deeper groundwater. Sequential electromagnetic logs show movement of high-chloride water from delta sediments to pumping wells through permeable interconnected aquifer layers. δD and δ18O data show most groundwater originated as recharge along the front of the Sierra Nevada, but tritium and carbon-14 data suggest recharge rates in this area are low and have decreased over recent geologic time. Managed aquifer recharge at two sites show differences in water-level responses to recharge and in the physical movement of recharged water with depth related to subsurface geology. Well-bore flow logs also show rapid movement of water from recharge sites through permeable interconnected aquifer layers to pumping wells.

Sensitivity of the Gravity Recovery and Climate Experiment (GRACE) to the complexity of aquifer systems for monitoring of groundwater

Science.gov (United States)

Katpatal, Yashwant B.; Rishma, C.; Singh, Chandan K.

2018-05-01

The Gravity Recovery and Climate Experiment (GRACE) satellite mission is aimed at assessment of groundwater storage under different terrestrial conditions. The main objective of the presented study is to highlight the significance of aquifer complexity to improve the performance of GRACE in monitoring groundwater. Vidarbha region of Maharashtra, central India, was selected as the study area for analysis, since the region comprises a simple aquifer system in the western region and a complex aquifer system in the eastern region. Groundwater-level-trend analyses of the different aquifer systems and spatial and temporal variation of the terrestrial water storage anomaly were studied to understand the groundwater scenario. GRACE and its field application involve selecting four pixels from the GRACE output with different aquifer systems, where each GRACE pixel encompasses 50-90 monitoring wells. Groundwater storage anomalies (GWSA) are derived for each pixel for the period 2002 to 2015 using the Release 05 (RL05) monthly GRACE gravity models and the Global Land Data Assimilation System (GLDAS) land-surface models (GWSAGRACE) as well as the actual field data (GWSAActual). Correlation analysis between GWSAGRACE and GWSAActual was performed using linear regression. The Pearson and Spearman methods show that the performance of GRACE is good in the region with simple aquifers; however, performance is poorer in the region with multiple aquifer systems. The study highlights the importance of incorporating the sensitivity of GRACE in estimation of groundwater storage in complex aquifer systems in future studies.

Carbonate and carbon isotopic evolution of groundwater contaminated by produced water brine with hydrocarbons

International Nuclear Information System (INIS)

Atekwana, Eliot A.; Seeger, Eric J.

2015-01-01

The major ionic and dissolved inorganic carbon (DIC) concentrations and the stable carbon isotope composition of DIC (δ"1"3C_D_I_C) were measured in a freshwater aquifer contaminated by produced water brine with petroleum hydrocarbons. Our aim was to determine the effects of produced water brine contamination on the carbonate evolution of groundwater. The groundwater was characterized by three distinct anion facies: HCO_3"−-rich, SO_4"2"−-rich and Cl"−-rich. The HCO_3"−-rich groundwater is undergoing closed system carbonate evolution from soil CO_2_(_g_) and weathering of aquifer carbonates. The SO_4"2"−-rich groundwater evolves from gypsum induced dedolomitization and pyrite oxidation. The Cl"−-rich groundwater is contaminated by produced water brine and undergoes common ion induced carbonate precipitation. The δ"1"3C_D_I_C of the HCO_3"−-rich groundwater was controlled by nearly equal contribution of carbon from soil CO_2_(_g_) and the aquifer carbonates, such that the δ"1"3C of carbon added to the groundwater was −11.6‰. In the SO_4"2"−-rich groundwater, gypsum induced dedolomitization increased the "1"3C such that the δ"1"3C of carbon added to the groundwater was −9.4‰. In the produced water brine contaminated Cl"−-rich groundwater, common ion induced precipitation of calcite depleted the "1"3C such that the δ"1"3C of carbon added to the groundwater was −12.7‰. The results of this study demonstrate that produced water brine contamination of fresh groundwater in carbonate aquifers alters the carbonate and carbon isotopic evolution. - Highlights: • We studied carbonate and δ"1"3C evolution in groundwater contaminated by produced water brine. • Multiple processes affect the carbonate and δ"1"3C evolution of the groundwater. • The processes are carbonate weathering, dedolomitization and common ion induce calcite precipitation. • The δ"1"3C added to DIC was −11.6‰ for weathering, −9.4‰ for dedolomitization

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.

Microbial community evolution during simulated managed aquifer recharge in response to different biodegradable dissolved organic carbon (BDOC) concentrations

KAUST Repository

Li, Dong

2013-05-01

This study investigates the evolution of the microbial community in laboratory-scale soil columns simulating the infiltration zone of managed aquifer recharge (MAR) systems and analogous natural aquifer sediment ecosystems. Parallel systems were supplemented with either moderate (1.1 mg/L) or low (0.5 mg/L) biodegradable dissolved organic carbon (BDOC) for a period of six months during which time, spatial (1 cm, 30 cm, 60 cm, 90 cm, and 120 cm) and temporal (monthly) analyses of sediment-associated microbial community structure were analyzed. Total microbial biomass associated with sediments was positively correlated with BDOC concentration where a significant decline in BDOC was observed along the column length. Analysis of 16S rRNA genes indicated dominance by Bacteria with Archaea comprising less than 1 percent of the total community. Proteobacteria was found to be the major phylum in samples from all column depths with contributions from Betaproteobacteria, Alphaproteobacteria and Gammaproteobacteria. Microbial community structure at all the phylum, class and genus levels differed significantly at 1 cm between columns receiving moderate and low BDOC concentrations; in contrast strong similarities were observed both between parallel column systems and across samples from 30 to 120 cm depths. Samples from 1 cm depth of the low BDOC columns exhibited higher microbial diversity (expressed as Shannon Index) than those at 1 cm of moderate BDOC columns, and both increased from 5.4 to 5.9 at 1 cm depth to 6.7-8.3 at 30-120 cm depths. The microbial community structure reached steady state after 3-4 months since the initiation of the experiment, which also resulted in an improved DOC removal during the same time period. This study suggested that BDOC could significantly influence microbial community structure regarding both composition and diversity of artificial MAR systems and analogous natural aquifer sediment ecosystems. © 2013 Elsevier Ltd.

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

Numerical Simulation of Borehole Flow in Deep Monitor Wells, Pearl Harbor Aquifer, Oahu, Hawaii

Science.gov (United States)

Rotzoll, K.; Oki, D. S.; El-Kadi, A. I.

2010-12-01

Salinity profiles collected from uncased deep monitor wells are commonly used to monitor freshwater-lens thickness in coastal aquifers. However, vertical flow in these wells can cause the measured salinity to differ from salinity in the adjacent aquifer. Substantial borehole flow has been observed in uncased wells in the Pearl Harbor aquifer, Oahu, Hawaii. A numerical modeling approach, incorporating aquifer hydraulic characteristics and recharge rates representative of the Pearl Harbor aquifer, was used to evaluate the effects of borehole flow on measured salinity profiles from deep monitor wells. Borehole flow caused by vertical hydraulic gradients associated with the natural regional groundwater-flow system and local groundwater withdrawals was simulated. Model results were used to estimate differences between vertical salinity profiles in deep monitor wells and the adjacent aquifer in areas of downward, horizontal, and upward flow within the regional flow system—for cases with and without nearby pumped wells. Aquifer heterogeneity, represented in the model as layers of contrasting permeability, was incorporated in model scenarios. Results from this study provide insight into the magnitude of the differences between vertical salinity profiles from deep monitor wells and the salinity distributions in the aquifers. These insights are relevant and are critically needed for management and predictive modeling purposes.

Benzene dynamics and biodegradation in alluvial aquifers affected by river fluctuations.

Science.gov (United States)

Batlle-Aguilar, J; Morasch, B; Hunkeler, D; Brouyère, S

2014-01-01

The spatial distribution and temporal dynamics of a benzene plume in an alluvial aquifer strongly affected by river fluctuations was studied. Benzene concentrations, aquifer geochemistry datasets, past river morphology, and benzene degradation rates estimated in situ using stable carbon isotope enrichment were analyzed in concert with aquifer heterogeneity and river fluctuations. Geochemistry data demonstrated that benzene biodegradation was on-going under sulfate reducing conditions. Long-term monitoring of hydraulic heads and characterization of the alluvial aquifer formed the basis of a detailed modeled image of aquifer heterogeneity. Hydraulic conductivity was found to strongly correlate with benzene degradation, indicating that low hydraulic conductivity areas are capable of sustaining benzene anaerobic biodegradation provided the electron acceptor (SO4 (2-) ) does not become rate limiting. Modeling results demonstrated that the groundwater flux direction is reversed on annual basis when the river level rises up to 2 m, thereby forcing the infiltration of oxygenated surface water into the aquifer. The mobilization state of metal trace elements such as Zn, Cd, and As present in the aquifer predominantly depended on the strong potential gradient within the plume. However, infiltration of oxygenated water was found to trigger a change from strongly reducing to oxic conditions near the river, causing mobilization of previously immobile metal species and vice versa. MNA appears to be an appropriate remediation strategy in this type of dynamic environment provided that aquifer characterization and targeted monitoring of redox conditions are adequate and electron acceptors remain available until concentrations of toxic compounds reduce to acceptable levels. © 2013, National Ground Water Association.

Aquifer test at well SMW-1 near Moenkopi, Arizona

Science.gov (United States)

Carruth, Rob; Bills, Donald J.

2012-01-01

The Hopi villages of Lower Moencopi and Upper Moenkopi are on the Hopi Indian Reservation south of Tuba City in northern Arizona. These adjacent Hopi villages, located west and north of the confluence of Pasture Canyon Wash and Moenkopi Wash, are dependent on groundwater withdrawals from three wells that penetrate the N aquifer and from two springs that discharge from the N aquifer. The N aquifer is the principal aquifer in this region of northern Arizona and is composed of thick beds of sandstone between less permeable layers of siltstone and mudstone. The fine-grained character of the N aquifer inhibits rapid movement of water and large yields to wells; however, the aquifer is moderately productive at yields generally less than 25 gallons per minute in the study area. In recent years, the water level has declined in the three public-supply wells and the flow from the springs has decreased, causing concern that the current water supply will not be able to accommodate peak demand and allow for residential and economic growth. In addition to the challenge imposed by declining groundwater levels, the water-supply wells and springs are located about 2 miles downgradient from the Tuba City Landfill site where studies are ongoing to determine if uranium and other metals in groundwater beneath the landfill are higher than regional concentrations in the N aquifer. In August 2008, the U.S. Geological Survey, in cooperation with the Hopi Tribe, conducted an aquifer test on well SMW-1, designed to help the Hopi Tribe determine the potential yield and water quality of the N aquifer south of Moenkopi Wash as a possible source of additional water supply. Well SMW-1 was drilled south of Moenkopi Wash to a depth of 760 feet below land surface before being backfilled and cased to about 300 feet. The well penetrates, in descending order, the Navajo Sandstone and the Kayenta Formation, both units of the N aquifer. The pre-test water level in the well was 99.15 feet below land

Regional allocation of carbon emission quotas in China: Evidence from the Shapley value method

International Nuclear Information System (INIS)

Zhang, Yue-Jun; Wang, Ao-Dong; Da, Ya-Bin

2014-01-01

It is an important task for China to allocate carbon emission quotas among regions so as to realize its carbon reduction targets and establish the national cap-and-trade carbon market. Meanwhile, it is supposed to be cost-effective to jointly reduce China's carbon emissions through some collaborative activities among regions. Then a natural question is how to allocate the quotas among regions in light of the collaboration. For this purpose, the Shapley value method is adopted and the results show that, first, the regions with higher GDP, higher carbon outflow and higher carbon reduction connection should be allocated more carbon quotas. Moreover, when the collaboration is considered, the optimal allocation of carbon quotas among regions will change significantly compared to the basic quotas by the entropy method; and the Central region is allocated the largest proportion of carbon quota among regions, which indicates its largest radiation effect. Besides, the collaboration between the Central region and Northern coast region, and that between the Central region and the Eastern region should be paid close attention. These results may provide insightful support for decision makers to promote collaborative carbon reduction and allocate carbon quotas in China. - Highlights: • The paper allocates carbon quotas given the collaboration among regions in China. • The Shapley value method coupled with the entropy and gravity models is adopted. • The regions with higher GDP, carbon outflow and reduction connection allocate more. • The Central region has the largest radiation effect on others among all regions. • The collaboration of the Central and Northern coast regions should have priority

Attenuation of landfill leachate by UK Triassic sandstone aquifer materials. 1. Fate of inorganic pollutants in laboratory columns

Science.gov (United States)

Thornton, Steven F.; Tellam, John H.; Lerner, David N.

2000-05-01

The attenuation of inorganic contaminants in acetogenic and methanogenic landfill leachate by calcareous and carbonate-deficient, oxide-rich Triassic sandstone aquifer materials from the English Midlands was examined in laboratory columns. Aqueous equilibrium speciation modelling, simple transport modelling and chemical mass balance approaches are used to evaluate the key processes and aquifer geochemical properties controlling contaminant fate. The results indicate that leachate-rock interactions are dominated by ion-exchange processes, acid-base and redox reactions and sorption/precipitation of metal species. Leachate NH 4 is attenuated by cation exchange with the aquifer sediments; however, NH 4 migration could be described with a simple model using retardation factors. Organic acids in the acetogenic leachate buffered the system pH at low levels during flushing of the calcareous aquifer material. In contrast, equilibrium with Al oxyhydroxide phases initially buffered pH (˜4.5) during flushing of the carbonate-deficient sandstone with methanogenic leachate. This led to the mobilisation of sorbed and oxide-bound heavy metals from the aquifer sediment which migrated as a concentrated pulse at the leachate front. Abiotic reductive dissolution of Mn oxyhydroxides on each aquifer material by leachate Fe 2+ maintains high concentrations of dissolved Mn and buffers the leachate inorganic redox system. This feature is analogous to the Mn-reducing zones found in leachate plumes and in the experiments provides a sink for the leachate Fe load and other heavy metals. The availability of reactive solid phase Mn oxyhydroxides limits the duration of redox buffering and Fe attenuation by these aquifer sediments. Aquifer pH and redox buffering capacity exert a fundamental influence on leachate inorganic contaminant fate in these systems. The implications for the assessment of aquifer vulnerability at landfills are discussed and simple measurements of aquifer properties which

Numerical simulation of groundwater flow in the Columbia Plateau Regional Aquifer System, Idaho, Oregon, and Washington

Science.gov (United States)

Ely, D. Matthew; Burns, Erick R.; Morgan, David S.; Vaccaro, John J.

2014-01-01

A three-dimensional numerical model of groundwater flow was constructed for the Columbia Plateau Regional Aquifer System (CPRAS), Idaho, Oregon, and Washington, to evaluate and test the conceptual model of the system and to evaluate groundwater availability. The model described in this report can be used as a tool by water-resource managers and other stakeholders to quantitatively evaluate proposed alternative management strategies and assess the long‑term availability of groundwater. The numerical simulation of groundwater flow in the CPRAS was completed with support from the Groundwater Resources Program of the U.S. Geological Survey Office of Groundwater.

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...

Seasonal Hydrologic Controls on Uranium and Iron Biogeochemistry in a Riparian Aquifer

Science.gov (United States)

Wilkins, M.; Williams, K. H.; Danczak, R. E.; Yabusaki, S.; Fang, Y.; Hobson, C.

2015-12-01

The maintenance of geochemically reducing conditions is generally optimal for the formation and preservation of reduced metals and mineral phases that can limit contaminant fate and transport. At a riparian aquifer near Rifle, CO, we tracked over six months the biogeochemical response within the aquifer to an annual pulse of dissolved oxygen (DO) that results from snowmelt-driven changes in Colorado River stage. In reduced portions of the aquifer (naturally reduced zones; NRZs) the re-oxidation of abundant iron sulfide minerals was the dominant oxygen-consuming process, and resulted in little DO intrusion into the deeper aquifer. In less reduced areas, DO intruded through the entire vertical profile of the aquifer. Across both regions, these perturbations resulted in changes to the microbial community structure, and aqueous metal pools. Two potentially different mechanisms of uranium mobilization were observed; (1) re-oxidation of reduced U(IV) phases in response to DO intrusion, and (2) mobilization of U(VI) from the vadose zone during water table rise. This high-resolution, long-term monitoring of aquifer biogeochemistry at the Rifle site has revealed dynamic microbial and geochemical responses to predictable, annual hydrologic perturbations, and offers an opportunity to further refine modeling approaches for such regions.

Flow of river water into a karstic limestone aquifer-2. Dating the young fraction in groundwater mixtures in the Upper Floridan aquifer near Valdosta, Georgia

Energy Technology Data Exchange (ETDEWEB)

Plummer, L.N.; Busenberg, E. [U.S. Geological Survey, 432 National Center, Reston, VA (United States); Drenkard, S.; Schlosser, P.; Ekwurzel, B.; Weppernig, R. [Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY (United States); McConnell, J.B. [U.S. Geological Survey, 3039 Amwiler Rd., Atlanta, GA (United States); Michel, R.L. [U.S. Geological Survey, Mail Stop 434, 345 Middlefield Road, Menlo Park, CA (United States)

1998-11-01

Tritium/helium-3 ({sup 3}H/{sup 3}He) and chlorofluorocarbon (CFCs, CFC-11, CFC-12, CFC-113) data are used to date the young fraction in groundwater mixtures from a karstic limestone aquifer near Valdosta, Georgia, where regional paleowater in the Upper Floridan aquifer receives recharge from two young sources-the flow of Withlacoochee River water through sinkholes in the river bed, and leakage of infiltration water through post-Eocene semi-confining beds above the Upper Floridan aquifer. In dating the young fraction of mixtures using CFCs, it is necessary to reconstruct the CFC concentration that was in the young fraction prior to mixing. The {sup 3}H/{sup 3}He age is independent of the extent of dilution with older ({sup 3}H-free and {sup 3}He{sub trit}-free) water. The groundwater mixtures are designated as Type-1 for mixtures of regional paleowater and regional infiltration water and Type-2 for mixtures containing more than approximately 4% of river water. The fractions of regional paleowater, regional infiltration water, and Withlacoochee River water in the groundwater mixtures were determined from Cl{sup -} and {delta}{sup 18}O data for water from the Upper Floridan aquifer at Valdosta, Georgia.The chlorofluorocarbons CFC-11 and CFC-113 are removed by microbial degradation and/or sorption processes in most anaerobic (Type-2) groundwater at Valdosta, but are present in some aerobic Type-1 water. CFC-12 persists in both SO{sub 4}-reducing and methanogenic water. The very low detection limits for CFCs (approximately 0.3 pg kg{sup -1}) permitted CFC-11 and CFC-12 dating of the fraction of regional infiltration water in Type-1 mixtures, and CFC-12 dating of the river-water fraction in Type-2 mixtures. Overall, approximately 50% of the 85 water samples obtained from the Upper Floridan aquifer have CFC-12-based ages of the young fraction that are consistent with the {sup 3}H concentration of the groundwater. Because of uncertainties associated with very low {sup 3}H

Flow of river water into a karstic limestone aquifer-2. Dating the young fraction in groundwater mixtures in the Upper Floridan aquifer near Valdosta, Georgia

International Nuclear Information System (INIS)

Plummer, L.N.; Busenberg, E.; Drenkard, S.; Schlosser, P.; Ekwurzel, B.; Weppernig, R.; McConnell, J.B.; Michel, R.L.

1998-01-01

Tritium/helium-3 ( 3 H/ 3 He) and chlorofluorocarbon (CFCs, CFC-11, CFC-12, CFC-113) data are used to date the young fraction in groundwater mixtures from a karstic limestone aquifer near Valdosta, Georgia, where regional paleowater in the Upper Floridan aquifer receives recharge from two young sources-the flow of Withlacoochee River water through sinkholes in the river bed, and leakage of infiltration water through post-Eocene semi-confining beds above the Upper Floridan aquifer. In dating the young fraction of mixtures using CFCs, it is necessary to reconstruct the CFC concentration that was in the young fraction prior to mixing. The 3 H/ 3 He age is independent of the extent of dilution with older ( 3 H-free and 3 He trit -free) water. The groundwater mixtures are designated as Type-1 for mixtures of regional paleowater and regional infiltration water and Type-2 for mixtures containing more than approximately 4% of river water. The fractions of regional paleowater, regional infiltration water, and Withlacoochee River water in the groundwater mixtures were determined from Cl - and δ 18 O data for water from the Upper Floridan aquifer at Valdosta, Georgia.The chlorofluorocarbons CFC-11 and CFC-113 are removed by microbial degradation and/or sorption processes in most anaerobic (Type-2) groundwater at Valdosta, but are present in some aerobic Type-1 water. CFC-12 persists in both SO 4 -reducing and methanogenic water. The very low detection limits for CFCs (approximately 0.3 pg kg -1 ) permitted CFC-11 and CFC-12 dating of the fraction of regional infiltration water in Type-1 mixtures, and CFC-12 dating of the river-water fraction in Type-2 mixtures. Overall, approximately 50% of the 85 water samples obtained from the Upper Floridan aquifer have CFC-12-based ages of the young fraction that are consistent with the 3 H concentration of the groundwater. Because of uncertainties associated with very low 3 H and 3 He content in dilute mixtures, 3 H/ 3 He dating is

Water-Rock Interactions in the Peridotite Aquifer of the Oman-UAE Ophiolite: Strontium Isotopic Ratio and Geochemical Evolution of Groundwater

Science.gov (United States)

Bompard, Nicolas; Matter, Juerg; Teagle, Damon

2016-04-01

The peridotite aquifer in Wadi Tayin, Sultanate of Oman, is a perfect example of natural carbonation of ultramafic rocks. In situ mineral carbonation is considered the most safest and permanent option of CO2 Capture and Sequestration (CCS). However, the process itself is yet to be characterised and a better understanding of the mechanisms involved in natural mineral carbonation is needed before geo-engineering it. We used the 87Sr/86Sr system to follow the water-rock interactions along the groundwater flowpath in the peridotite aquifer and to determine the sources of divalent cations (Mg2+, Ca2+) required for mineral carbonation. The Sr-isotope data of groundwater show that the aquifer rocks are the main source for divalent cations (Mg2+, Ca2+ and Sr2+) and secondary carbonates are their main sink. The groundwater 87Sr/86Sr ratio evolves with its pH: from 87Sr/86Sr = 0.7087 (n=3) to 0.7082 (n=8) between pH 7 and 8, and from 0.7086 (n=6) at pH 9 to 0.07075 (n=9) at pH 11. This evolution seems to support a two-step model for the water-rock interactions in the peridotite aquifer. From pH 7 to 8, secondary Ca-carbonate precipitation buffers the pH rise resulting from peridotite serpentinisation. From pH 9 to 11, peridotite serpentinisation drives the pH to alkaline condition. The change from a Mg-rich to a Ca-rich groundwater at pH 9 seems to confirm the two-step model.

Aquifer configuration and geostructural links control the groundwater quality in thin-bedded carbonate-siliciclastic alternations of the Hainich CZE, central Germany

Science.gov (United States)

Kohlhepp, Bernd; Lehmann, Robert; Seeber, Paul; Küsel, Kirsten; Trumbore, Susan E.; Totsche, Kai U.

2017-12-01

The quality of near-surface groundwater reservoirs is controlled, but also threatened, by manifold surface-subsurface interactions. Vulnerability studies typically evaluate the variable interplay of surface factors (land management, infiltration patterns) and subsurface factors (hydrostratigraphy, flow properties) in a thorough way, but disregard the resulting groundwater quality. Conversely, hydrogeochemical case studies that address the chemical evolution of groundwater often lack a comprehensive analysis of the structural buildup. In this study, we aim to reconstruct the actual spatial groundwater quality pattern from a synoptic analysis of the hydrostratigraphy, lithostratigraphy, pedology and land use in the Hainich Critical Zone Exploratory (Hainich CZE). This CZE represents a widely distributed yet scarcely described setting of thin-bedded mixed carbonate-siliciclastic strata in hillslope terrains. At the eastern Hainich low-mountain hillslope, bedrock is mainly formed by alternated marine sedimentary rocks of the Upper Muschelkalk (Middle Triassic) that partly host productive groundwater resources. Spatial patterns of the groundwater quality of a 5.4 km long well transect are derived by principal component analysis and hierarchical cluster analysis. Aquifer stratigraphy and geostructural links were deduced from lithological drill core analysis, mineralogical analysis, geophysical borehole logs and mapping data. Maps of preferential recharge zones and recharge potential were deduced from digital (soil) mapping, soil survey data and field measurements of soil hydraulic conductivities (Ks). By attributing spatially variable surface and subsurface conditions, we were able to reconstruct groundwater quality clusters that reflect the type of land management in their preferential recharge areas, aquifer hydraulic conditions and cross-formational exchange via caprock sinkholes or ascending flow. Generally, the aquifer configuration (spatial arrangement of strata

The relationship of the Yucca Mountain repository block to the regional ground-water system: A geochemical model

International Nuclear Information System (INIS)

Matuska, N.A.; Hess, J.W.

1989-08-01

Yucca Mountain, in southern Nevada, is being studied by the Department of Energy and the State of Nevada as the site of a high-level nuclear waste repository. Geochemical and isotopic modeling were used in this study to define the relationship of the volcanic tuff aquifers and aquitards to the underlying regional carbonate ground-water system. The chemical evolution of a ground water as it passes through a hypothetical tuffaceous aquifer was developed using computer models PHREEQE, WATEQDR and BALANCE. The tuffaceous system was divided into five parts, with specific mineralogies, reaction steps and temperatures. The initial solution was an analysis of a soil water from Rainier Mesa. The ending solution in each part became the initial solution in the next part. Minerals consisted of zeolites, smectites, authigenic feldspars and quartz polymorphs from described diagentic mineral zones. Reaction steps were ion exchange with zeolites. The solution from the final zone, Part V, was chosen as most representative, in terms of pH, element molalities and mineral solubilities, of tuffaceous water. This hypothetical volcanic water from Part V was mixed with water from the regional carbonate aquifer, and the results compared to analyses of Yucca Mountain wells. Mixing and modeling attempts were conducted on wells in which studies indicated upward flow

Integrated subsurface water solutions for coastal environments through integrated pump&treat and aquifer storage and recovery (ASR) schemes

Science.gov (United States)

Perdikaki, Martha; Kallioras, Andreas; Christoforidis, Christophoros; Iossifidis, Dimitris; Zafeiropoulos, Anastasios; Dimitriadis, Klisthenis; Makropoulos, Christos; Raat, Klaasjan; van den Berg, Gerard

2016-04-01

Coastal wetlands in semi-arid regions, as in Circum-Mediterranean, are considered important ecosystems that provide valuable services to human population and the environment, such as: flood protection, erosion control, wildlife habitat, water quality, recreation and carbon sequestration. Un-managed surface and groundwater exploitation in these areas usually leads to deterioration of such sensitive ecosystems by means of water resources degradation and/or increased salinity. Groundwater usually plays a vital role for the sustainability of these hydrological systems, as the underlying aquifers operate as regulators for both quantity and quality of their waters. Multi-layer and multi-objective Managed Aquifer Recharge (MAR) systems can be proved effective groundwater engineered solutions for the restoration of deteriorated coastal wetlands in semi- and arid regions. The plain of Marathon is a typical Mediterranean environment that hosts a naturally occurring -and today degraded- coastal wetland with the characteristics of a distinct ecosystem linked to a typical coastal hydrogeological system of a semi-arid region; and therefore can serve as a model for similar systems world-wide. The geo-hydrological setting of the area involves a multi-layer aquifer system consisting of (i) an upper un-consolidated formation of depositional unit dominated mostly by fluvial sediments and (ii) the surrounding and underlying karstified marbles; both being linked to the investigated wetland and also subjected to seawater encroachment. A smart engineered MAR system via an optimised Pump & Treat system integrated with an Aquifer Storage and Recovery (ASR) scheme in this area would include the abstraction of brackish groundwater from the deeper karst aquifer at a location close to the shoreline and direct treatment with Reverse Osmosis (RO). for desalination. Two-fold re-use scheme of the purified effluent can then be engineered for (i) the restoration of the coastal wetland; and (ii

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

Residence times of groundwater and nitrate transport in coastal aquifer systems: Daweijia area, northeastern China

International Nuclear Information System (INIS)

Han, Dongmei; Cao, Guoliang; McCallum, James; Song, Xianfang

2015-01-01

Groundwater within the coastal aquifer systems of the Daweijia area in northeastern China is characterized by a large of variations (33–521 mg/L) in NO_3"− concentrations. Elevated nitrate concentrations, in addition to seawater intrusion in the Daweijia well field, both attributable to anthropogenic activities, may impact future water-management practices. Chemical and stable isotopic (δ"1"8O, δ"2H) analysis, "3H and CFCs methods were applied to provide a better understanding of the relationship between the distribution of groundwater mean residence time (MRT) and nitrate transport, and to identify sources of nitrate concentrations in the complex coastal aquifer systems. There is a relatively narrow range of isotopic composition (ranging from − 8.5 to − 7.0‰) in most groundwater. Generally higher tritium contents observed in the wet season relative to the dry season may result from rapid groundwater circulation in response to the rainfall through the preferential flow paths. In the well field, the relatively increased nitrate concentrations of groundwater, accompanied by the higher tritium contents in the wet season, indicate the nitrate pollution can be attributed to domestic wastes. The binary exponential and piston-flow mixing model (BEP) yielded feasible age distributions based on the conceptual model. The good inverse relationship between groundwater MRTs (92–467 years) and the NO_3"− concentrations in the shallow Quaternary aquifers indicates that elevated nitrate concentrations are attributable to more recent recharge for shallow groundwater. However, there is no significant relationship between the MRTs (8–411 years) and the NO_3"− concentrations existing in the carbonate aquifer system, due to the complex hydrogeological conditions, groundwater age distributions and the range of contaminant source areas. Nitrate in the groundwater system without denitrification effects could accumulate and be transported for tens of years, through the

Residence times of groundwater and nitrate transport in coastal aquifer systems: Daweijia area, northeastern China

Energy Technology Data Exchange (ETDEWEB)

Han, Dongmei [Key Laboratory of Water Cycle & Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China); National Centre for Groundwater Research and Training, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Cao, Guoliang [National Centre for Groundwater Research and Training, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Center for Water Research, College of Engineering, Peking University, Beijing 100871 (China); McCallum, James [National Centre for Groundwater Research and Training, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); School of the Environment, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Song, Xianfang [Key Laboratory of Water Cycle & Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China)

2015-12-15

Groundwater within the coastal aquifer systems of the Daweijia area in northeastern China is characterized by a large of variations (33–521 mg/L) in NO{sub 3}{sup −} concentrations. Elevated nitrate concentrations, in addition to seawater intrusion in the Daweijia well field, both attributable to anthropogenic activities, may impact future water-management practices. Chemical and stable isotopic (δ{sup 18}O, δ{sup 2}H) analysis, {sup 3}H and CFCs methods were applied to provide a better understanding of the relationship between the distribution of groundwater mean residence time (MRT) and nitrate transport, and to identify sources of nitrate concentrations in the complex coastal aquifer systems. There is a relatively narrow range of isotopic composition (ranging from − 8.5 to − 7.0‰) in most groundwater. Generally higher tritium contents observed in the wet season relative to the dry season may result from rapid groundwater circulation in response to the rainfall through the preferential flow paths. In the well field, the relatively increased nitrate concentrations of groundwater, accompanied by the higher tritium contents in the wet season, indicate the nitrate pollution can be attributed to domestic wastes. The binary exponential and piston-flow mixing model (BEP) yielded feasible age distributions based on the conceptual model. The good inverse relationship between groundwater MRTs (92–467 years) and the NO{sub 3}{sup −} concentrations in the shallow Quaternary aquifers indicates that elevated nitrate concentrations are attributable to more recent recharge for shallow groundwater. However, there is no significant relationship between the MRTs (8–411 years) and the NO{sub 3}{sup −} concentrations existing in the carbonate aquifer system, due to the complex hydrogeological conditions, groundwater age distributions and the range of contaminant source areas. Nitrate in the groundwater system without denitrification effects could accumulate and be

The Midwest Regional Carbon Sequestration Partnership (MRCSP)

Energy Technology Data Exchange (ETDEWEB)

James J. Dooley; Robert Dahowski; Casie Davidson

2005-12-01

This final report summarizes the Phase I research conducted by the Midwest regional Carbon Sequestration Partnership (MRCSP). The Phase I effort began in October 2003 and the project period ended on September 31, 2005. The MRCSP is a public/private partnership led by Battelle with the mission of identifying the technical, economic, and social issues associated with implementation of carbon sequestration technologies in its seven state geographic region (Indiana, Kentucky, Maryland, Michigan, Ohio, Pennsylvania, and West Virginia) and identifying viable pathways for their deployment. It is one of seven partnerships that together span most of the U.S. and parts of Canada that comprise the U.S. Department of Energy's (DOE's) Regional Carbon Sequestration Program led by DOE's national Energy Technology Laboratory (NETL). The MRCSP Phase I research was carried out under DOE Cooperative Agreement No. DE-FC26-03NT41981. The total value of Phase I was $3,513,513 of which the DOE share was $2,410,967 or 68.62%. The remainder of the cost share was provided in varying amounts by the rest of the 38 members of MRCSP's Phase I project. The next largest cost sharing participant to DOE in Phase I was the Ohio Coal Development Office within the Ohio Air Quality Development Authority (OCDO). OCDO's contribution was $100,000 and was contributed under Grant Agreement No. CDO/D-02-17. In this report, the MRCSP's research shows that the seven state MRCSP region is a major contributor to the U. S. economy and also to total emissions of CO2, the most significant of the greenhouse gases thought to contribute to global climate change. But, the research has also shown that the region has substantial resources for sequestering carbon, both in deep geological reservoirs (geological sequestration) and through improved agricultural and land management practices (terrestrial sequestration). Geological reservoirs, especially deep saline reservoirs, offer the potential

Geochemical Investigation of the Arbuckle-Simpson Aquifer, South-Central Oklahoma, 2004-06

Science.gov (United States)

Christenson, Scott; Hunt, Andrew G.; Parkhurst, David L.

2009-01-01

dolomite. The major ion chemistry for these 34 samples is consistent with a set of water-rock interactions. Rainfall infiltrates the soil zone, where the host rock, limestone or dolomite, dissolves as a result of uptake of carbon dioxide gas. Some continued dissolution of dolomite and precipitation of calcite occur as the water flows through the saturated zone. The major ion chemistry of the two samples from wells completed in the confined part of the aquifer indicates the water is a sodium chloride type. Geochemical inverse modeling determined that mixing of calcite-saturated recharge water with brine and dissolving calcite, dolomite, and gypsum accounts for the water composition of these two samples. One of the two samples, collected at Vendome Well in Chickasaw National Recreation Area, had a mixing fraction of brine of about 1 percent. The brine component of the sample at Vendome Well is likely to account for the relatively large concentrations of many of the trace elements (potassium, fluoride, bromide, iodide, ammonia, arsenic, boron, lithium, selenium, and strontium) measured in the water sample. Carbon-14, helium-3/tritium, and chlorofluorocarbons were used to calculate ground-water ages, recharge temperatures, and mixtures of ground water in the Arbuckle-Simpson aquifer. Thirty four of 36 water samples recharged the aquifer after 1950, indicating that water is moving quickly from recharge areas to discharge at streams and springs. Two exceptions to this classification were noted in samples 6 and 15 (Vendome Well). Ground-water ages determined for these two samples by using carbon-14 are 34,000 years (site 6) and 10,500 years (site 15). Concentrations of dissolved argon, neon, and xenon in water samples were used to determine the temperature of the water when it recharged the aquifer. The mean annual air temperature at Ada, Oklahoma, is 16 degrees Celsius (C) and the median temperature of the 30 reconnaissance water samples was 18.1 C. The av

Determination of the origin of dissolved inorganic carbon in groundwater around a reclaimed landfill in Otwock using stable carbon isotopes

Energy Technology Data Exchange (ETDEWEB)

Porowska, Dorota, E-mail: dorotap@uw.edu.pl

2015-05-15

Highlights: • Research showed the origin of DIC in the groundwater around a reclaimed landfill. • Carbon isotope was used to evaluate the contributions of carbon from different sources. • The leachate-contaminated water was isotopically distinct from the natural groundwater. • DIC in the natural groundwater comes from organic matter and dissolution of carbonates. • In the contaminated water, DIC comes from organic matter in the aquifer and landfill. - Abstract: Chemical and isotopic analyses of groundwater from piezometers located around a reclaimed landfill in Otwock (Poland) were performed in order to trace the origin of dissolved inorganic carbon (DIC) in the groundwater. Due to differences in the isotopic composition of carbon from different sources, an analysis of stable carbon isotopes in the groundwater, together with the Keeling plot approach and a two-component mixing model allow us to evaluate the relative contributions of carbon from these sources in the groundwater. In the natural (background) groundwater, DIC concentrations and the isotopic composition of DIC (δ{sup 13}C{sub DIC}) comes from two sources: decomposition of organic matter and carbonate dissolution within the aquifer sediments, whereas in the leachate-contaminated groundwater, DIC concentrations and δ{sup 13}C{sub DIC} values depend on the degradation of organic matter within the aquifer sediments and biodegradation of organic matter stored in the landfill. From the mixing model, about 4–54% of the DIC pool is derived from organic matter degradation and 96–46% from carbonate dissolution in natural conditions. In the leachate-contaminated groundwater, about 20–53% of the DIC is derived from organic matter degradation of natural origin and 80–47% from biodegradation of organic matter stored in the landfill. Partial pressure of CO{sub 2} (P CO{sub 2}) was generally above the atmospheric, hence atmospheric CO{sub 2} as a source of carbon in DIC pool was negligible in the

Coastal Aquifer Contamination and Geochemical Processes Evaluation in Tugela Catchment, South Africa—Geochemical and Statistical Approaches

Directory of Open Access Journals (Sweden)

Badana Ntanganedzeni

2018-05-01

Full Text Available Assessment of groundwater quality, contamination sources and geochemical processes in the coastal aquifer of Tugela Catchment, South Africa were carried out by the geochemical and statistical approach using major ion chemistry of 36 groundwater samples. Results suggest that the spatial distribution pattern of EC, TDS, Na, Mg, Cl and SO4 are homogenous and elevated concentrations are observed in the wells in the coastal region and few wells near the Tugela River. Wells located far from the coast are enriched by Ca, HCO3 and CO3. Durov diagrams, Gibbs plots, ionic ratios, chloro alkaline indices (CAI1 and CAI2 and correlation analysis imply that groundwater chemistry in the coastal aquifer of Tugela Catchment is regulated by the ion exchange, mineral dissolution, saline sources, and wastewater infiltration from domestic sewage; septic tank leakage and irrigation return flow. Principle component analysis also ensured the role of saline and anthropogenic sources and carbonates dissolution on water chemistry. Spatial distributions of factor score also justify the above predictions. Groundwater suitability assessment indicates that around 80% and 90% of wells exceeded the drinking water standards recommended by the WHO and South African drinking water standards (SAWQG, respectively. Based on SAR, RSC, PI, and MH classifications, most of the wells are suitable for irrigation in the study region. USSL classification suggests that groundwater is suitable for coarse-textured soils and salt-tolerant crops. The study recommends that a proper management plan is required to protect this coastal aquifer efficiently.

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.

Characterisation of Fractures and Fracture Zones in a Carbonate Aquifer Using Electrical Resistivity Tomography and Pricking Probe Methodes

Science.gov (United States)

Szalai, Sandor; Kovacs, Attila; Kuslits, Lukács; Facsko, Gabor; Gribovszki, Katalin; Kalmar, Janos; Szarka, Laszlo

2018-04-01

Position, width and fragmentation level of fracture zones and position, significance and characteristic distance of fractures were aimed to determine in a carbonate aquifer. These are fundamental parameters, e.g. in hydrogeological modelling of aquifers, due to their role in subsurface water movements. The description of small scale fracture systems is however a challenging task. In the test area (Kádárta, Bakony Mts, Hungary), two methods proved to be applicable to get reasonable information about the fractures: Electrical Resistivity Tomography (ERT) and Pricking-Probe (PriP). PriP is a simple mechanical tool which has been successfully applied in archaeological investigations. ERT results demonstrated its applicability in this small scale fracture study. PriP proved to be a good verification tool both for fracture zone mapping and detecting fractures, but in certain areas, it produced different results than the ERT. The applicability of this method has therefore to be tested yet, although its problems most probably origin from human activity which reorganises the near-surface debris distribution. In the test site, both methods displayed fracture zones including a very characteristic one and a number of individual fractures and determined their characteristic distance and significance. Both methods prove to be able to produce hydrogeologically important parameters even individually, but their simultaneous application is recommended to decrease the possible discrepancies.

Carbon Sequestration in Saline Aquifers: Modeling Diffusive and Convective Transport Of a Carbon-­Dioxide Cap

KAUST Repository

Allen, Rebecca

2011-01-01

done on the diffusive-convective transport that occurs under a cap of CO2-saturated fluid, which results after CO2 is injected into an aquifer and spreads laterally under an area of low permeability. The diffusive-convective modeling reveals an enhanced

Probabilistic modelling and uncertainty analysis of flux and water balance changes in a regional aquifer system due to coal seam gas development.

Science.gov (United States)

Sreekanth, J; Cui, Tao; Pickett, Trevor; Rassam, David; Gilfedder, Mat; Barrett, Damian

2018-09-01

Large scale development of coal seam gas (CSG) is occurring in many sedimentary basins around the world including Australia, where commercial production of CSG has started in the Surat and Bowen basins. CSG development often involves extraction of large volumes of water that results in depressurising aquifers that overlie and/or underlie the coal seams thus perturbing their flow regimes. This can potentially impact regional aquifer systems that are used for many purposes such as irrigation, and stock and domestic water. In this study, we adopt a probabilistic approach to quantify the depressurisation of the Gunnedah coal seams and how this impacts fluxes to, and from the overlying Great Artesian Basin (GAB) Pilliga Sandstone aquifer. The proposed method is suitable when effects of a new resource development activity on the regional groundwater balance needs to be assessed and account for large scale uncertainties in the groundwater flow system and proposed activity. The results indicated that the extraction of water and gas from the coal seam could potentially induce additional fluxes from the Pilliga Sandstone to the deeper formations due to lowering pressure heads in the coal seams. The median value of the rise in the maximum flux from the Pilliga Sandstone to the deeper formations is estimated to be 85ML/year, which is considered insignificant as it forms only about 0.29% of the Long Term Annual Average Extraction Limit of 30GL/year from the groundwater management area. The probabilistic simulation of the water balance components indicates only small changes being induced by CSG development that influence interactions of the Pilliga Sandstone with the overlying and underlying formations and with the surface water courses. The current analyses that quantified the potential maximum impacts of resource developments and how they influences the regional water balance, would greatly underpin future management decisions. Copyright © 2018 Elsevier B.V. All rights

Carbon dioxide in Arctic and subarctic regions

Energy Technology Data Exchange (ETDEWEB)

Gosink, T. A.; Kelley, J. J.

1981-03-01

A three year research project was presented that would define the role of the Arctic ocean, sea ice, tundra, taiga, high latitude ponds and lakes and polar anthropogenic activity on the carbon dioxide content of the atmosphere. Due to the large physical and geographical differences between the two polar regions, a comparison of CO/sub 2/ source and sink strengths of the two areas was proposed. Research opportunities during the first year, particularly those aboard the Swedish icebreaker, YMER, provided additional confirmatory data about the natural source and sink strengths for carbon dioxide in the Arctic regions. As a result, the hypothesis that these natural sources and sinks are strong enough to significantly affect global atmospheric carbon dioxide levels is considerably strengthened. Based on the available data we calculate that the whole Arctic region is a net annual sink for about 1.1 x 10/sup 15/ g of CO/sub 2/, or the equivalent of about 5% of the annual anthropogenic input into the atmosphere. For the second year of this research effort, research on the seasonal sources and sinks of CO/sub 2/ in the Arctic will be continued. Particular attention will be paid to the seasonal sea ice zones during the freeze and thaw periods, and the tundra-taiga regions, also during the freeze and thaw periods.

Conceptualization of the predevelopment groundwater flow system and transient water-level responses in Yucca Flat, Nevada National Security Site, Nevada

Science.gov (United States)

Fenelon, Joseph M.; Sweetkind, Donald S.; Elliott, Peggy E.; Laczniak, Randell J.

2012-01-01

Contaminants introduced into the subsurface of Yucca Flat, Nevada National Security Site, by underground nuclear testing are of concern to the U.S. Department of Energy and regulators responsible for protecting human health and safety. The potential for contaminant movement away from the underground test areas and into the accessible environment is greatest by groundwater transport. The primary hydrologic control on this transport is evaluated and examined through a set of contour maps developed to represent the hydraulic-head distribution within the two major aquifer systems underlying the area. Aquifers and confining units within these systems were identified and their extents delineated by merging and analyzing hydrostratigraphic framework models developed by other investigators from existing geologic information. Maps of the hydraulic-head distributions in the major aquifer systems were developed from a detailed evaluation and assessment of available water-level measurements. The maps, in conjunction with regional and detailed hydrogeologic cross sections, were used to conceptualize flow within and between aquifer systems. Aquifers and confining units are mapped and discussed in general terms as being one of two aquifer systems: alluvial-volcanic or carbonate. The carbonate aquifers are subdivided and mapped as independent regional and local aquifers, based on the continuity of their component rock. Groundwater flow directions, approximated from potentiometric contours, are indicated on the maps and sections and discussed for the alluvial-volcanic and regional carbonate aquifers. Flow in the alluvial-volcanic aquifer generally is constrained by the bounding volcanic confining unit, whereas flow in the regional carbonate aquifer is constrained by the siliceous confining unit. Hydraulic heads in the alluvial-volcanic aquifer typically range from 2,400 to 2,530 feet and commonly are elevated about 20-100 feet above heads in the underlying regional carbonate

Water-quality assessment of the Cambrian-Ordovician aquifer system in the northern Midwest, United States

Science.gov (United States)

Wilson, John T.

2012-01-01

This report provides a regional assessment of groundwater quality of the Cambrian-Ordovician aquifer system, based primarily on raw water samples collected by the NAWQA Program during 1995 through 2007. The NAWQA Program has published findings in local study-unit reports encompassing parts of the Cambrian-Ordovician aquifer system. Data collected from the aquifer system were used in national synthesis reports on selected topics such as specific water-quality constituent classes, well type, or aquifer material; however, a synthesis of groundwater quality at the principal aquifer scale has not been completed and is therefore the major purpose of this report. Water samples collected by the NAWQA Program were analyzed for various classes of characteristics including physical properties, major ions, trace elements, nutrients and dissolved organic carbon, radionuclides (tritium, radon, and radium), pesticides, and volatile organic compounds. Subsequent sections of this report provide discussions on these classes of characteristics. The assessment objectives of this report are to (1) summarize constituent concentrations and compare them to human-health benchmarks and non-health guidelines; (2) determine the geographic distribution of constituent concentrations and relate them to various factors such as confining conditions, well type, land use, and groundwater age; and (3) evaluate near-decadal-scale changes in nitrate concentrations and pesticide detections. The most recent sample collected from each well by the NAWQA Program was used for most analyses. Near-decadal-scale changes in nitrate concentrations and pesticide detections were evaluated for selected well networks by using the most recent sample from each well and comparing it to the results from a sample collected 7 or 11 years earlier. Because some of the NAWQA well networks provide a limited areal coverage of the aquifer system, data for raw water samples from other USGS sources and state agencies were included

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

International Nuclear Information System (INIS)

Pena, P.; Lopez, A.; Balcazar, M.; Flores, J.H.; Cardenas, S.; Schubert, M.

2005-01-01

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)

Hydrogeology and water-quality characteristics of the Lower Floridan aquifer in east-central Florida

Science.gov (United States)

O'Reilly, Andrew M.; Spechler, Rick M.; McGurk, Brian E.

2002-01-01

The hydrogeology and water-quality characteristics of the Lower Floridan aquifer and the relation of the Lower Floridan aquifer to the framework of the Floridan aquifer system were evaluated during a 6-year (1995-2001) study. The study area, a 7,500 square-mile area of east-central Florida, is underlain by three principal hydrogeologic units: the surficial aquifer system, the intermediate confining unit, and the Floridan aquifer system. The Floridan aquifer system, a carbonate-rock aquifer system composed of the Upper Floridan aquifer, a middle semiconfining unit, a middle confining unit, and the Lower Floridan aquifer, is the major source of water supply to east-central Florida. The Upper Floridan aquifer provides much of the water required to meet the current (2002) demand; however, the Lower Floridan aquifer is being used increasingly as a source of freshwater, particularly for municipal needs. For this reason, a better understanding of the aquifer is needed. The Lower Floridan aquifer is present throughout east-central Florida. The aquifer is composed of alternating beds of limestone and dolomite, and is characterized by abundant fractured dolomite zones and solution cavities. The altitude of the top of the Lower Floridan aquifer ranges from less than 600 feet below sea level in the northern part of the study area to more than 1,600 feet below sea level in the southwestern part. Thickness of the unit ranges from about 910 to 1,180 feet. The top of the Lower Floridan aquifer generally is marked by an increase in formation resistivity and by an increase in the occurrence of fractures and solution cavities within the carbonates. Also, a noticeable increase in borehole flow often marks the top of the unit. The bottom of the Lower Floridan aquifer is based on the first occurrence of evaporites. Ground-water in the Lower Floridan aquifer generally moves in a southwest-to-northeast direction across the study area. In September 1998, the altitude of the potentiometric

Characterising aquifer treatment for pathogens in managed aquifer recharge.

Science.gov (United States)

Page, D; Dillon, P; Toze, S; Sidhu, J P S

2010-01-01

In this study the value of subsurface treatment of urban stormwater during Aquifer Storage Transfer Recovery (ASTR) is characterised using quantitative microbial risk assessment (QMRA) methodology. The ASTR project utilizes a multi-barrier treatment train to treat urban stormwater but to date the role of the aquifer has not been quantified. In this study it was estimated that the aquifer barrier provided 1.4, 2.6, >6.0 log(10) removals for rotavirus, Cryptosporidium and Campylobacter respectively based on pathogen diffusion chamber results. The aquifer treatment barrier was found to vary in importance vis-à-vis the pre-treatment via a constructed wetland and potential post-treatment options of UV-disinfection and chlorination for the reference pathogens. The risk assessment demonstrated that the human health risk associated with potable reuse of stormwater can be mitigated (disability adjusted life years, DALYs aquifer is integrated with suitable post treatment options into a treatment train to attenuate pathogens and protect human health.

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...

Characterizing a complex aquifer system using geophysics, hydrodynamics and geochemistry: A new distribution of Miocene aquifers in the Zéramdine and Mahdia-Jébéniana blocks (east-central Tunisia)

Science.gov (United States)

Lachaal, Fethi; Bédir, Mourad; Tarhouni, Jamila; Gacha, Ayadi Ben; Leduc, Christian

2011-06-01

The Zéramdine and Mahdia-Jébéniana blocks are located in the Sahel region in east-central Tunisia. Active tectonics have divided the region into numerous sub-units, as result of multiple phases of distension and compression. The Miocene fluvio-deltaic sediment sandy layers have aquiferous capacities but their hydraulic properties are still unknown, due to the lack of investigation wells. This study proposes a new description of the regional hydrogeology of Miocene deposits. Seismic-reflection and wireline logging of petroleum and water wells were used to understand the structure and the geometry of the Miocene reservoirs. The groundwater flow and its relationship to the sedimentary and tectonic context were then identified by studying piezometry and hydrochemistry. Two Miocene deep aquifer systems were identified: (1) Zéramdine-Béni Hassen to the north and (2) Jébéniana-Ksour Essef to the south. These aquifers are separated by the Mahdia graben. Other major tectonic structures, such as the Zéramdine fault corridor, the Moknine graben, and the El-Jem half-graben represent lateral boundaries for these aquifers. Other deeper sandy and clayey-sandy reservoirs were also identified in the area. Their repartition, thickness and depth vary from one block to other. Hydrodynamics of the deep aquifers seems to be controlled by geological structures. Two independent compartments were identified: in the northern block groundwater flows from West to East and from Northwest to Southeast, while in the southern block it flows from Northwest to Southeast. Geochemical facies are of two types: Na-Ca-Cl-SO 4 for the Zéramdine-Béni Hassen deep aquifer and Na-Cl for the Jébéniana-Ksour Essef deep aquifer. The hydrodynamic and geochemical results confirm the sharing of the Miocene sediments into two aquifers.

Flow of river water into a Karstic limestone aquifer. 1. Tracing the young fraction in groundwater mixtures in the Upper Floridan Aquifer near Valdosta, Georgia

International Nuclear Information System (INIS)

Plummer, L.N.; Busenberg, E.; McConnell, J.B.; Drenkard, S.; Schlosser, P.; Michel, R.L.

1998-01-01

The quality of water in the Upper Floridan aquifer near Valdosta, Georgia is affected locally by discharge of Withlacoochee River water through sinkholes in the river bed. Data on transient tracers and other dissolved substances, including Cl - , 3 H, tritiogenic helium-3 ( 3 He), chlorofluorocarbons (CFC-11, CFC-12, CFC-113), organic C (DOC), O 2 (DO), H 2 S, CH 4 , δ 18 O, δD, and 14 C were investigated as tracers of Withlacoochee River water in the Upper Floridan aquifer. The concentrations of all tracers were affected by dilution and mixing. Dissolved Cl - , δ 18 O, δD, CFC-12, and the quantity ( 3 H+ 3 He) are stable in water from the Upper Floridan aquifer, whereas DOC, DO, H 2 S, CH 4 , 14 C, CFC-11, and CFC-113 are affected by microbial degradation and other geochemical processes occurring within the aquifer. Groundwater mixing fractions were determined by using dissolved Cl - and δ 18 O data, recognizing 3 end-member water types in the groundwater mixtures: (1) Withlacoochee River water (δ 18 O=-2.5±0.3per thousand, Cl - =12.2±2 mg/l), (2) regional infiltration water (δ 18 O=-4.2±0.1per thousand, Cl - =2.3±0.1 mg/l), and (3) regional paleowater resident in the Upper Floridan aquifer (δ 18 O=-3.4±0.1per thousand, Cl - =2.6±0.1 mg/l) (uncertainties are ±1σ). Error simulation procedures were used to define uncertainties in mixing fractions. Fractions of river water in groundwater range from 0 to 72% and average 10%. The influence of river-water discharge on the quality of water in the Upper Floridan aquifer was traced from the sinkhole area on the Withlacoochee River 25 km SE in the direction of regional groundwater flow. Infiltration of water is most significant to the N and NW of Valdosta, but becomes negligible to the S and SE in the direction of general thickening of post-Eocene confining beds overlying the Upper Floridan aquifer. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

Flow of river water into a Karstic limestone aquifer. 1. Tracing the young fraction in groundwater mixtures in the Upper Floridan Aquifer near Valdosta, Georgia

Energy Technology Data Exchange (ETDEWEB)

Plummer, L.N.; Busenberg, E. [U.S. Geological Survey, 432 National Center, Reston, VA (United States); McConnell, J.B. [U.S. Geological Survey, 3039 Amwiler Rd., Atlanta, GA (United States); Drenkard, S.; Schlosser, P. [Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY (United States); Michel, R.L. [U.S. Geological Survey, Mail Stop 434, 345 Middlefield Road, Menlo Park, CA (United States)

1998-11-01

he quality of water in the Upper Floridan aquifer near Valdosta, Georgia is affected locally by discharge of Withlacoochee River water through sinkholes in the river bed. Data on transient tracers and other dissolved substances, including Cl{sup -}, {sup 3}H, tritiogenic helium-3 ({sup 3}He), chlorofluorocarbons (CFC-11, CFC-12, CFC-113), organic C (DOC), O{sub 2} (DO), H{sub 2}S, CH{sub 4}, {delta}{sup 18}O, {delta}D, and {sup 14}C were investigated as tracers of Withlacoochee River water in the Upper Floridan aquifer. The concentrations of all tracers were affected by dilution and mixing. Dissolved Cl{sup -}, {delta}{sup 18}O, {delta}D, CFC-12, and the quantity ({sup 3}H+{sup 3}He) are stable in water from the Upper Floridan aquifer, whereas DOC, DO, H{sub 2}S, CH{sub 4}, {sup 14}C, CFC-11, and CFC-113 are affected by microbial degradation and other geochemical processes occurring within the aquifer. Groundwater mixing fractions were determined by using dissolved Cl{sup -} and {delta}{sup 18}O data, recognizing 3 end-member water types in the groundwater mixtures: (1) Withlacoochee River water ({delta}{sup 18}O=-2.5{+-}0.3per thousand, Cl{sup -}=12.2{+-}2 mg/l), (2) regional infiltration water ({delta}{sup 18}O=-4.2{+-}0.1per thousand, Cl{sup -}=2.3{+-}0.1 mg/l), and (3) regional paleowater resident in the Upper Floridan aquifer ({delta}{sup 18}O=-3.4{+-}0.1per thousand, Cl{sup -}=2.6{+-}0.1 mg/l) (uncertainties are {+-}1{sigma}). Error simulation procedures were used to define uncertainties in mixing fractions. Fractions of river water in groundwater range from 0 to 72% and average 10%. The influence of river-water discharge on the quality of water in the Upper Floridan aquifer was traced from the sinkhole area on the Withlacoochee River 25 km SE in the direction of regional groundwater flow. Infiltration of water is most significant to theN and NW of Valdosta, but becomes negligible to the S and SE in the direction of general thickening of post-Eocene confining

Subsurface imaging reveals a confined aquifer beneath an ice-sealed Antarctic lake

DEFF Research Database (Denmark)

Dugan, H. A.; Doran, P. T.; Tulaczyk, S.

2015-01-01

Liquid water oases are rare under extreme cold desert conditions found in the Antarctic McMurdo Dry Valleys. Here we report geophysical results that indicate that Lake Vida, one of the largest lakes in the region, is nearly frozen and underlain by widespread cryoconcentrated brine. A ground...... this zone to be a confined aquifer situated in sediments with a porosity of 23-42%. Discovery of this aquifer suggests that subsurface liquid water may be more pervasive in regions of continuous permafrost than previously thought and may represent an extensive habitat for microbial populations. Key Points...... Geophysical survey finds low resistivities beneath a lake in Antarctic Dry Valleys Liquid brine abundant beneath Antarctic lake Aquifer provides microbial refugium in cold desert environment...

Aquifers in the Sokoto basin, northwestern Nigeria, with a description of the general hydrogeology of the region

Science.gov (United States)

Anderson, H.R.; Ogilbee, William

1973-01-01

The Sokoto Basin of northwestern Nigeria lies in the sub-Saharan Sudan belt of west Africa in a zone of savannah-type vegetation. Rainfall, averaging about 30 inches annually in much of the basin, occurs chiefly in a wet season which lasts from May to October. A prolonged dry season extending from October to April is dominated by dusty harmattan winds from the northeast. April and May are the hottest months, when temperatures occasionally reach 105?F. Flow in streams of the Sokoto Basin is mostly overland runoff. Only in a few reaches, fed by ground-water discharge from the sedimentary rocks, are streams perennial. In the River Zamfara basin, ground-water discharge contributes almost 1 inch of the average 3.33 inches of total annual runoff. In the vicinity of Sokoto, the River Rima flows throughout the year sustained by spring discharge from perched ground water in limestone of the Kalambaina Formation. On the crystalline terrane where most of the streams rise, total annual runoff may exceed 5 inches, very little of which is ground-water discharge. The sedimentary rocks of the basin range in age from Cretaceous to Tertiary and are composed mostly of interbedded sand, clay, and some limestone; the beds dip gently toward the northwest. Alluvium of Quaternary age underlies the lowlands of the River Sokoto (now Sokoto) and its principal tributaries. These rocks contain three important artesian aquifers, in addition to regional unconfined ground-water bodies in all the principal outcron areas, and a perched water body in the outcrop of the Kalambaina Formation. Artesian aquifers occur at depth in the Gundumi Formation, the Rima Group, and the Gwandu Formation and are separated from one another by clay beds in the lower part of the Rima Group and the Dange Formation. In outcrop, clay in the Dange Formation also supports the perched water of the Kalambaina Formation. The Gundumi Formation, resting on the basement complex, is composed of varicolored clay, sand, and gravel

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

Science.gov (United States)

Rabelo, Jorge Luiz; Wendland, Edson

2009-11-01

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

Potential yields of wells in unconsolidated aquifers in upstate New York-- Adirondack sheet

Science.gov (United States)

Bugliosi, Edward F.; Trudell, Ruth A.; Casey, George D.

1988-01-01

This map shows the location and potential well yield from unconsolidated aquifers in the Adirondack region at a 1:250,000 scale. It also delineates segments of aquifers that are heavily used by community water systems and designated by the New York State Department of Environmental Conservation as ' Primary Water Supply ' aquifers and cites published reports that give detailed information on each area. Most aquifers were deposited in low-lying areas such as valleys or plains during deglaciation of the region. Thick, permeable, well-sorted sand and gravel deposits generally yield large quantities of water, greater than 100 gal/min. Thin sand, sand and gravel deposits, or thicker gravel units have a large content of silt and fine sand, yield moderate amounts of water, 10 to 100 gal/min. Wells dug in till and those drilled in bedrock commonly yield less than 10 gal/min. (USGS)

Assessing water quality and pollution origin of the Bou-Areg aquifer (north east Morocco)

OpenAIRE

Alonso, A.; Sbaa, M.; Vanclooster, M.

2011-01-01

This study aims to evaluate the quality of the groundwater and the sources of pollution of the Bou-Areg aquifer, situated in the Oriental region, in the northeast part of Morocco. We first elaborated the aquifer pollution risk map by crossing a vulnerability map, principally based on the physical characteristics of the area, with a pressures map based on the soil occupation. The resulting map showed that the aquifer is subjected to a medium to high risk for at least half of the total aquifer ...

Determination of the origin of dissolved inorganic carbon in groundwater around a reclaimed landfill in Otwock using stable carbon isotopes.

Science.gov (United States)

Porowska, Dorota

2015-05-01

Chemical and isotopic analyses of groundwater from piezometers located around a reclaimed landfill in Otwock (Poland) were performed in order to trace the origin of dissolved inorganic carbon (DIC) in the groundwater. Due to differences in the isotopic composition of carbon from different sources, an analysis of stable carbon isotopes in the groundwater, together with the Keeling plot approach and a two-component mixing model allow us to evaluate the relative contributions of carbon from these sources in the groundwater. In the natural (background) groundwater, DIC concentrations and the isotopic composition of DIC (δ(13)CDIC) comes from two sources: decomposition of organic matter and carbonate dissolution within the aquifer sediments, whereas in the leachate-contaminated groundwater, DIC concentrations and δ(13)CDIC values depend on the degradation of organic matter within the aquifer sediments and biodegradation of organic matter stored in the landfill. From the mixing model, about 4-54% of the DIC pool is derived from organic matter degradation and 96-46% from carbonate dissolution in natural conditions. In the leachate-contaminated groundwater, about 20-53% of the DIC is derived from organic matter degradation of natural origin and 80-47% from biodegradation of organic matter stored in the landfill. Partial pressure of CO2 (P CO2) was generally above the atmospheric, hence atmospheric CO2 as a source of carbon in DIC pool was negligible in the aquifer. P CO2 values in the aquifer in Otwock were always one to two orders of magnitude above the atmospheric P CO2, and thus CO2 escaped directly into the vadose zone. Copyright © 2015 Elsevier Ltd. All rights reserved.

Decadal oscillation of lakes and aquifers in the upper Great Lakes region of North America: hydroclimatic implications

Science.gov (United States)

Watras, C.J.; Read, J.S.; Holman, K.D.; Liu, Z.; Song, Y.-Y.; Watras, A.J.; Morgan, S.; Stanley, E.H.

2014-01-01

We report a unique hydrologic time-series which indicates that water levels in lakes and aquifers across the upper Great Lakes region of North America have been dominated by a climatically-driven, near-decadal oscillation for at least 70 years. The historical oscillation (~13y) is remarkably consistent among small seepage lakes, groundwater tables and the two largest Laurentian Great Lakes despite substantial differences in hydrology. Hydrologic analyses indicate that the oscillation has been governed primarily by changes in the net atmospheric flux of water (P-E) and stage-dependent outflow. The oscillation is hypothetically connected to large-scale atmospheric circulation patterns originating in the mid-latitude North Pacific that support the flux of moisture into the region from the Gulf of Mexico. Recent data indicate an apparent change in the historical oscillation characterized by a ~12y downward trend beginning in 1998. Record low water levels region-wide may mark the onset of a new hydroclimatic regime.

The Use of Stable Water Isotopes as Tracers in Soil Aquifer Treatment (SAT and in Regional Water Systems

Directory of Open Access Journals (Sweden)

Ido Negev

2017-01-01

Full Text Available This study examines the feasibility of tracing and quantifying the progress of different water sources along the water–effluent–SAT (Soil Aquifer Treatment chain using 2H and 18O isotopes. The research was conducted at the Dan Region Reclamation Plant (Shafdan, which reclaims ~135 MCM/year of effluent for irrigation. Water samples representing different stages along the chain were taken in two surveys during 2010–2011 and 2014. δ18O and δ2H values were used for mixing ratios (MR calculations, and compared with calculated MRs using chloride and carbamazepine concentrations. The results showed a relative enrichment of 18O and 2H in the Israeli water system compared to the regional groundwater, due to the addition of massive quantities of desalinated water. A linear correlation for δ2H vs. δ18O with a slope of 4.5 was found for the different freshwater sources and their mixing products, suggesting evaporation-mixing effects. MR values indicate on the spreading of new type of effluent originating from desalinated water in the aquifer. A dilution model explains the isotopic compositions in the water system and of the Shafdan effluents. Water isotopes have an advantage over other tracers, due to the ability to predict their ratio in the supply system and in the effluent, based on mass balance calculations and on knowledge of water supply volumes.

[Carbon sequestration status of forest ecosystems in Ningxia Hui Autonomous Region].

Science.gov (United States)

Gao, Yang; Jin, Jing-Wei; Cheng, Ji-Min; Su, Ji-Shuai; Zhu, Ren-Bin; Ma, Zheng-Rui; Liu, Wei

2014-03-01

Based on the data of Ningxia Hui Autonomous Region forest resources inventory, field investigation and laboratory analysis, this paper studied the carbon sequestration status of forest ecosystems in Ningxia region, estimated the carbon density and storage of forest ecosystems, and analyzed their spatial distribution characteristics. The results showed that the biomass of each forest vegetation component was in the order of arbor layer (46.64 Mg x hm(-2)) > litterfall layer (7.34 Mg x hm(-2)) > fine root layer (6.67 Mg x hm(-2)) > shrub-grass layer (0.73 Mg x hm(-2)). Spruce (115.43 Mg x hm(-2)) and Pinus tabuliformis (94.55 Mg x hm(-2)) had higher vegetation biomasses per unit area than other tree species. Over-mature forest had the highest arbor carbon density among the forests with different ages. However, the young forest had the highest arbor carbon storage (1.90 Tg C) due to its widest planted area. Overall, the average carbon density of forest ecosystems in Ningxia region was 265.74 Mg C x hm(-2), and the carbon storage was 43.54 Tg C. Carbon density and storage of vegetation were 27.24 Mg C x hm(-2) and 4.46 Tg C, respectively. Carbon storage in the soil was 8.76 times of that in the vegetation. In the southern part of Ningxia region, the forest carbon storage was higher than in the northern part, where the low C storage was mainly related to the small forest area and young forest age structure. With the improvement of forest age structure and the further implementation of forestry ecoengineering, the forest ecosystems in Ningxia region would achieve a huge carbon sequestration potential.

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

Simultaneous counter-flow of chlorinated volatile organic compounds across the saturated-unsaturated interface region of an aquifer.

Science.gov (United States)

Ronen, Daniel; Lev-Wiener, Hagit; Graber, Ellen R; Dahan, Ofer; Weisbrod, Noam

2010-04-01

Concentrations of chlorinated volatile organic compounds (Cl-VOCs) at the saturated-unsaturated interface region (SUIR; depth of approximately 18m) of a sandy phreatic aquifer were measured in two monitoring wells located 25m apart. The concentrations of the Cl-VOCs obtained above and below the water table along a 413-day period are interpreted to depict variable, simultaneous and independent movement of trichlorothene, tetrachloroethene, 1,1-dichloroethene, cis-1,2-dichloroethene, 1,1,1-trichloroethane, chloroform and 1,1-dichloroethane vapors in opposite directions across the SUIR. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Heat storage in the Hettangian aquifer in Berlin - results from a column experiment

Science.gov (United States)

Milkus, Chri(Sch)augott

2015-04-01

Aquifer Thermal Energy Storage (ATES) is a sustainable alternative for storage and seasonal availability of thermal energy. However, its impact on the subsurface flow regime is not well known. In Berlin (Germany), the Jurassic (Hettangian) sandstone aquifer with highly mineralized groundwater (TDS 27 g/L) is currently used for heat storage. The aim of this study was to examine the hydrogeochemical changes that are caused by the induced temperature shift and its effects on the hydraulic permeability of the aquifer. Column experiments were conducted, in which stainless steel columns were filled with sediment from the aquifer and flushed with native groundwater for several weeks. The initial temperature of the experiment was 20°C, comparable to the in-situ conditions within the aquifer. After reaching equilibrium between sediment and water, the temperature was increased to simulate heating of the aquifer. During the experiment, physical and chemical parameters (pH, ORP, dissolved oxygen and dissolved carbon dioxide) were measured at the outflow of the column and the effluent water was sampled. Using a Scanning Electron Microscope, the deposition of precipitated minerals and biofilm on sediment grains was analyzed. Changes in hydraulic properties of the sediment were studied by the use of tracer tests with Uranin.

Modeling CO₂ Sequestration in Saline Aquifer and Depleted Oil Reservoir To Evaluate Regional CO₂ Sequestration Potential of Ozark Plateau Aquifer System, South-Central Kansas

Energy Technology Data Exchange (ETDEWEB)

Watney, W. Lynn [University Of Kansas Center For Research, Inc. Lawrence, KS (United States); Rush, Jason [University Of Kansas Center For Research, Inc. Lawrence, KS (United States); Raney, Jennifer [University Of Kansas Center For Research, Inc. Lawrence, KS (United States)

2014-09-30

1. Drilled, cored, and logged three wells to the basement and collecting more than 2,700 ft of conventional core; obtained 20 mⁱ² of multicomponent 3D seismic imaging and merged and reprocessed more than 125 mi² of existing 3D seismic data for use in modeling CO₂- EOR oil recovery and CO₂ storage in five oil fields in southern Kansas. 2. Determined the technical feasibility of injecting and sequestering CO₂ in a set of four depleted oil reservoirs in the Cutter, Pleasant Prairie South, Eubank, and Shuck fields in southwest Kansas; of concurrently recovering oil from those fields; and of quantifying the volumes of CO2 sequestered and oil recovered during the process. 3. Formed a consortium of six oil operating companies, five of which own and operate the four fields. The consortium became part of the Southwest Kansas CO₂-EOR Initiative for the purpose of sharing data, knowledge, and interest in understanding the potential for CO₂-EOR in Kansas. 4. Built a regional well database covering 30,000 mi² and containing stratigraphic tops from ~90,000 wells; correlated 30 major stratigraphic horizons; digitized key wells, including wireline logs and sample logs; and analyzed more than 3,000 drill stem tests to establish that fluid levels in deep aquifers below the Permian evaporites are not connected to the surface and therefore pressures are not hydrostatic. Connectivity with the surface aquifers is lacking because shale aquitards and impermeable evaporite layers consist of both halite and anhydrite. 5. Developed extensive web applications and an interactive mapping system that do the following: a. Facilitate access to a wide array of data obtained in the study, including core descriptions and analyses, sample logs, digital (LAS) well logs, seismic data, gravity and magnetics maps, structural and stratigraphic maps, inferred fault traces, earthquakes, Class I and II disposal wells, and

Modeling CO₂ Sequestration in Saline Aquifer and Depleted Oil Reservoir To Evaluate Regional CO₂ Sequestration Potential of Ozark Plateau Aquifer System, South-Central Kansas

Energy Technology Data Exchange (ETDEWEB)

Watney, W. Lynn [University Of Kansas Center For Research, Inc. Lawrence, KS (United States)

2014-09-30

1. Drilled, cored, and logged three wells to the basement and collecting more than 2,700 ft of conventional core; obtained 20 mⁱ² of multicomponent 3D seismic imaging and merged and reprocessed more than 125 mi² of existing 3D seismic data for use in modeling CO₂- EOR oil recovery and CO₂ storage in five oil fields in southern Kansas. 2. Determined the technical feasibility of injecting and sequestering CO₂ in a set of four depleted oil reservoirs in the Cutter, Pleasant Prairie South, Eubank, and Shuck fields in southwest Kansas; of concurrently recovering oil from those fields; and of quantifying the volumes of CO2 sequestered and oil recovered during the process. 3. Formed a consortium of six oil operating companies, five of which own and operate the four fields. The consortium became part of the Southwest Kansas CO₂-EOR Initiative for the purpose of sharing data, knowledge, and interest in understanding the potential for CO₂-EOR in Kansas. 4. Built a regional well database covering 30,000 mi² and containing stratigraphic tops from ~90,000 wells; correlated 30 major stratigraphic horizons; digitized key wells, including wireline logs and sample logs; and analyzed more than 3,000 drill stem tests to establish that fluid levels in deep aquifers below the Permian evaporites are not connected to the surface and therefore pressures are not hydrostatic. Connectivity with the surface aquifers is lacking because shale aquitards and impermeable evaporite layers consist of both halite and anhydrite. 5. Developed extensive web applications and an interactive mapping system that do the following: a. Facilitate access to a wide array of data obtained in the study, including core descriptions and analyses, sample logs, digital (LAS) well logs, seismic data, gravity and magnetics maps, structural and stratigraphic maps, inferred fault traces, earthquakes, Class I and II disposal wells, and

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.

Geochemistry of the Springfield Plateau aquifer of the Ozark Plateaus Province in Arkansas, Kansas, Missouri and Oklahoma, USA

Science.gov (United States)

Adamski, J.C.

2000-01-01

Geochemical data indicate that the Springfield Plateau aquifer, a carbonate aquifer of the Ozark Plateaus Province in central USA, has two distinct hydrochemical zones. Within each hydrochemical zone, water from springs is geochemically and isotopically different than water from wells. Geochemical data indicate that spring water generally interacts less with the surrounding rock and has a shorter residence time, probably as a result of flowing along discrete fractures and solution openings, than water from wells. Water type throughout most of the aquifer was calcium bicarbonate, indicating that carbonate-rock dissolution is the primary geochemical process occurring in the aquifer. Concentrations of calcium, bicarbonate, dissolved oxygen and tritium indicate that most ground water in the aquifer recharged rapidly and is relatively young (less than 40 years). In general, field-measured properties, concentrations of many chemical constituents, and calcite saturation indices were greater in samples from the northern part of the aquifer (hydrochemical zone A) than in samples from the southern part of the aquifer (hydrochemical zone B). Factors affecting differences in the geochemical composition of ground water between the two zones are difficult to identify, but could be related to differences in chert content and possibly primary porosity, solubility of the limestone, and amount and type of cementation between zone A than in zone B. In addition, specific conductance, pH, alkalinity, concentrations of many chemical constituents and calcite saturation indices were greater in samples from wells than in samples from springs in each hydrochemical zone. In contrast, concentrations of dissolved oxygen, nitrite plus nitrate, and chloride generally were greater in samples from springs than in samples from wells. Water from springs generally flows rapidly through large conduits with minimum water-rock interactions. Water from wells flow through small fractures, which restrict

Microbial community evolution during simulated managed aquifer recharge in response to different biodegradable dissolved organic carbon (BDOC) concentrations.

Science.gov (United States)

Li, Dong; Alidina, Mazahirali; Ouf, Mohamed; Sharp, Jonathan O; Saikaly, Pascal; Drewes, Jörg E

2013-05-01

This study investigates the evolution of the microbial community in laboratory-scale soil columns simulating the infiltration zone of managed aquifer recharge (MAR) systems and analogous natural aquifer sediment ecosystems. Parallel systems were supplemented with either moderate (1.1 mg/L) or low (0.5 mg/L) biodegradable dissolved organic carbon (BDOC) for a period of six months during which time, spatial (1 cm, 30 cm, 60 cm, 90 cm, and 120 cm) and temporal (monthly) analyses of sediment-associated microbial community structure were analyzed. Total microbial biomass associated with sediments was positively correlated with BDOC concentration where a significant decline in BDOC was observed along the column length. Analysis of 16S rRNA genes indicated dominance by Bacteria with Archaea comprising less than 1 percent of the total community. Proteobacteria was found to be the major phylum in samples from all column depths with contributions from Betaproteobacteria, Alphaproteobacteria and Gammaproteobacteria. Microbial community structure at all the phylum, class and genus levels differed significantly at 1 cm between columns receiving moderate and low BDOC concentrations; in contrast strong similarities were observed both between parallel column systems and across samples from 30 to 120 cm depths. Samples from 1 cm depth of the low BDOC columns exhibited higher microbial diversity (expressed as Shannon Index) than those at 1 cm of moderate BDOC columns, and both increased from 5.4 to 5.9 at 1 cm depth to 6.7-8.3 at 30-120 cm depths. The microbial community structure reached steady state after 3-4 months since the initiation of the experiment, which also resulted in an improved DOC removal during the same time period. This study suggested that BDOC could significantly influence microbial community structure regarding both composition and diversity of artificial MAR systems and analogous natural aquifer sediment ecosystems. Copyright © 2013 Elsevier Ltd

Hydraulic contacts identification in the aquifers of limestone ridges: tracer tests in the Montelago pilot area (Central Apennines

Directory of Open Access Journals (Sweden)

Alberto Tazioli

2016-08-01

Full Text Available The investigated area, located in the inner part of the Marche region (central Italy and belonging to the carbonate Umbria- Marche ridges in the central Apennines, is characterised by very complex geo-structural setting and widespread karst phenomena that make difficult the definition of the relation among the aquifers basing only on the hydrogeological survey. Hence, the presence of different flowpaths among aquifers of the Umbria-Marche hydrostratigraphic sequence and of tectonic contacts among the different structures is verified using tracer tests. In particular, the tests showed that the Calcare Massiccio and the Maiolica aquifers are connected under certain tectonic conditions. A new tracer given by a single stranded DNA molecule and traditional fluorescent dyes have been injected into the Montelago sinkhole in different periods (during the recharge and during the discharge and recovered in several points along the expected hydrogeological basin, using either manual and automatic sampling. Fluorescent traps were positioned in creeks, rivers and springs. The DNA molecule is useful to trace surface water and groundwater, is detectable even at very low concentrations, no significant change in water density and viscosity can be observed and its use is not dangerous for the environment. The results stress the suitability of DNA as hydrogeological tracer, capable to identify connections among aquifers and study different flowpaths even in high flow conditions when traditional tracers are more and more diluted. Moreover, fluorescein tracer allowed for the transport parameter determination, giving mean velocities ranging from 100 to 3000 m/day and mean residence time from some tens to hundreds of hours, and determining the aquifer volumes.

Numerical simulation of CO2 disposal by mineral trapping in deep aquifers

International Nuclear Information System (INIS)

Xu Tianfu; Apps, John A.; Pruess, Karsten

2004-01-01

Carbon dioxide disposal into deep aquifers is a potential means whereby atmospheric emissions of greenhouse gases may be reduced. However, our knowledge of the geohydrology, geochemistry, geophysics, and geomechanics of CO 2 disposal must be refined if this technology is to be implemented safely, efficiently, and predictably. As a prelude to a fully coupled treatment of physical and chemical effects of CO 2 injection, the authors have analyzed the impact of CO 2 immobilization through carbonate mineral precipitation. Batch reaction modeling of the geochemical evolution of 3 different aquifer mineral compositions in the presence of CO 2 at high pressure were performed. The modeling considered the following important factors affecting CO 2 sequestration: (1) the kinetics of chemical interactions between the host rock minerals and the aqueous phase, (2) CO 2 solubility dependence on pressure, temperature and salinity of the system, and (3) redox processes that could be important in deep subsurface environments. The geochemical evolution under CO 2 injection conditions was evaluated. In addition, changes in porosity were monitored during the simulations. Results indicate that CO 2 sequestration by matrix minerals varies considerably with rock type. Under favorable conditions the amount of CO 2 that may be sequestered by precipitation of secondary carbonates is comparable with and can be larger than the effect of CO 2 dissolution in pore waters. The precipitation of ankerite and siderite is sensitive to the rate of reduction of Fe(III) mineral precursors such as goethite or glauconite. The accumulation of carbonates in the rock matrix leads to a considerable decrease in porosity. This in turn adversely affects permeability and fluid flow in the aquifer. The numerical experiments described here provide useful insight into sequestration mechanisms, and their controlling geochemical conditions and parameters

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.

Effects of a Reservoir Water on the GW Quality in a Coastal Aquifer of Semi-arid Region, North-east of Tunisia

Science.gov (United States)

Uchida, C.; Kawachi, A.; Tsujimura, M.; Tarhouni, J.

2015-12-01

This study investigated effects of a reservoir water in a salinized shallow aquifer based on spatial distribution of geochemical properties in groundwater (GW). In many coastal shallow aquifers of arid and semi-arid regions, groundwater table (GWT) depression and salinization have occurred due to GW overexploitation. In Korba aquifer, north-east of Tunisia, after a dam reservoir has been constructed in order to assure a water resource for irrigation, improvement of GW level and quality have been observed in the downstream area of the dam (area-A), while the GW in the other area (area-B) still has high salinity. This study, therefore, aimed to investigate the effects of the reservoir water on the GW quality. In June 2013, water quality survey and sampling were carried out at 60 wells (GW), a dam reservoir, river and the sea. Major ions, boron, bromide, and oxygen-18 and deuterium in collected samples were analyzed. From the results, in the area-B, the GWT was lower than the sea level and the high salinity were observed. The Br- concentration of the GW was correlated with the Cl- concentration, and the values of B/Cl- and Br-/Cl- of the GW were similar to the seawater. Since the GWT depression allowed the seawater to intrude into the aquifer, the GW salinization occurred in this area. On the other hand, in the area-A, GWT was higher than the seawater level, and the Na+ and Cl- concentrations were lower than the area-B. Especially, in the irrigated areas by using the reservoir water, the isotopic values, B/Cl- and Br-/Cl- of the GW were relatively higher than the others. The reservoir water has high isotopic values due to evaporation effect, and the B/Cl- and Br-/Cl- values become higher due to organic matters in sediment of the reservoir or soil in the filtration process. Thus, in addition to the direct infiltration from the reservoir into the aquifer, irrigation using a reservoir water probably has a positive impact on the GW quality in this area.

Microbial Reduction of Fe(III) and SO42- and Associated Microbial Communities in the Alluvial Aquifer Groundwater and Sediments.

Science.gov (United States)

Lee, Ji-Hoon; Lee, Bong-Joo

2017-11-25

Agricultural demands continuously increased use of groundwater, causing drawdown of water table and need of artificial recharge using adjacent stream waters. River water intrusion into groundwater can alter the geochemical and microbiological characteristics in the aquifer and subsurface. In an effort to investigate the subsurface biogeochemical activities before operation of artificial recharge at the test site, established at the bank of Nakdong River, Changwon, South Korea, organic carbon transported from river water to groundwater was mimicked and the effect on the indigenous microbial communities was investigated with the microcosm incubations of the groundwater and subsurface sediments. Laboratory incubations indicated microbial reduction of Fe(III) and sulfate. Next-generation Illumina MiSeq sequences of V4 region of 16S rRNA gene provided that the shifts of microbial taxa to Fe(III)-reducing and/or sulfate-reducing microorganisms such as Geobacter, Albidiferax, Desulfocapsa, Desulfuromonas, and Desulfovibrio were in good correlation with the sequential flourishment of microbial reduction of Fe(III) and sulfate as the incubations progressed. This suggests the potential role of dissolved organic carbons migrated with the river water into groundwater in the managed aquifer recharge system on the indigenous microbial community composition and following alterations of subsurface biogeochemistry and microbial metabolic activities.

Carbon Emissions from Deforestation in the Brazilian Amazon Region

Science.gov (United States)

Potter, C.; Klooster, S.; Genovese, V.

2009-01-01

A simulation model based on satellite observations of monthly vegetation greenness from the Moderate Resolution Imaging Spectroradiometer (MODIS) was used to estimate monthly carbon fluxes in terrestrial ecosystems of Brazilian Amazon and Cerrado regions over the period 2000-2002. The NASA-CASA (Carnegie Ames Stanford Approach) model estimates of annual forest production were used for the first time as the basis to generate a prediction for the standing pool of carbon in above-ground biomass (AGB; gC/sq m) for forested areas of the Brazilian Amazon region. Plot-level measurements of the residence time of carbon in wood in Amazon forest from Malhi et al. (2006) were interpolated by inverse distance weighting algorithms and used with CASA to generate a new regional map of AGB. Data from the Brazilian PRODES (Estimativa do Desflorestamento da Amazonia) project were used to map deforested areas. Results show that net primary production (NPP) sinks for carbon varied between 4.25 Pg C/yr (1 Pg=10(exp 15)g) and 4.34 Pg C for the region and were highest across the eastern and northern Amazon areas, whereas deforestation sources of CO2 flux from decomposition of residual woody debris were higher and less seasonal in the central Amazon than in the eastern and southern areas. Increased woody debris from past deforestation events was predicted to alter the net ecosystem carbon balance of the Amazon region to generate annual CO2 source fluxes at least two times higher than previously predicted by CASA modeling studies. Variations in climate, land cover, and forest burning were predicted to release carbon at rates of 0.5 to 1 Pg C/yr from the Brazilian Amazon. When direct deforestation emissions of CO2 from forest burning of between 0.2 and 0.6 Pg C/yr in the Legal Amazon are overlooked in regional budgets, the year-to-year variations in this net biome flux may appear to be large, whereas our model results implies net biome fluxes had actually been relatively consistent from

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

Aquifer Storage Recovery (ASR) of chlorinated municipal drinking water in a confined aquifer

Science.gov (United States)

Izbicki, John A.; Petersen, Christen E.; Glotzbach, Kenneth J.; Metzger, Loren F.; Christensen, Allen H.; Smith, Gregory A.; O'Leary, David R.; Fram, Miranda S.; Joseph, Trevor; Shannon, Heather

2010-01-01

About 1.02 x 106 m3 of chlorinated municipal drinking water was injected into a confined aquifer, 94-137 m below Roseville, California, between December 2005 and April 2006. The water was stored in the aquifer for 438 days, and 2.64 x 106 m3 of water were extracted between July 2007 and February 2008. On the basis of Cl data, 35% of the injected water was recovered and 65% of the injected water and associated disinfection by-products (DBPs) remained in the aquifer at the end of extraction. About 46.3 kg of total trihalomethanes (TTHM) entered the aquifer with the injected water and 37.6 kg of TTHM were extracted. As much as 44 kg of TTHMs remained in the aquifer at the end of extraction because of incomplete recovery of injected water and formation of THMs within the aquifer by reactions with freechlorine in the injected water. Well-bore velocity log data collected from the Aquifer Storage Recovery (ASR) well show as much as 60% of the injected water entered the aquifer through a 9 m thick, high-permeability layer within the confined aquifer near the top of the screened interval. Model simulations of ground-water flow near the ASR well indicate that (1) aquifer heterogeneity allowed injected water to move rapidly through the aquifer to nearby monitoring wells, (2) aquifer heterogeneity caused injected water to move further than expected assuming uniform aquifer properties, and (3) physical clogging of high-permeability layers is the probable cause for the observed change in the distribution of borehole flow. Aquifer heterogeneity also enhanced mixing of native anoxic ground water with oxic injected water, promoting removal of THMs primarily through sorption. A 3 to 4-fold reduction in TTHM concentrations was observed in the furthest monitoring well 427 m downgradient from the ASR well, and similar magnitude reductions were observed in depth-dependent water samples collected from the upper part of the screened interval in the ASR well near the end of the extraction

Evaporative concentration of arsenic in groundwater: health and environmental implications, La Laguna Region, Mexico.

Science.gov (United States)

Ortega-Guerrero, Adrián

2017-10-01

High arsenic concentrations in groundwater have been documented in La Laguna Region (LLR) in arid northern Mexico, where arsenic poisoning is both chronic and endemic. A heated debate has continued for decades on its origin. LLR consisted of a series of ancient connected lakes that developed at the end of a topographic depression under closed basin conditions. This study addresses the isotopic, chemical composition of the groundwater and geochemical modeling in the southeasternmost part of the LLR to determine the origin of arsenic. Groundwater samples were obtained from a carbonate and granular aquifers and from a clayey aquitard at terminal Viesca Lake. Results show that groundwater originated as meteoric water that reached the lakes mainly via abundant springs in the carbonate aquifer and perennial flooding of the Nazas-Aguanaval Rivers. Paleo-lake water underwent progressive evaporation as demonstrated by the enrichment of δ 18 O, δ 2 H and characteristic geochemical patterns in the granular aquifer and aquitard that resulted in highly saline (>90,000 mS/cm), arsenic-rich (up to 5000 μg/L) paleo-groundwater (>30,000 years BP). However, adsorption or co-precipitation on iron oxides, clay-mineral surfaces and organic carbon limited arsenic concentration in the groundwater. Arsenic-rich groundwater and other solutes are advancing progressively from the lacustrine margins toward the main granular aquifer, due to reversal of hydraulic gradients caused by intensive groundwater exploitation and the reduction in freshwater runoff provoked by dam construction on the main rivers. Desorption of arsenic will incorporate additional concentrations of arsenic into the groundwater and continue to have significant negative effects on human health and the environment.

San Pedro River Aquifer Binational Report

Science.gov (United States)

Callegary, James B.; Minjárez Sosa, Ismael; Tapia Villaseñor, Elia María; dos Santos, Placido; Monreal Saavedra, Rogelio; Grijalva Noriega, Franciso Javier; Huth, A. K.; Gray, Floyd; Scott, C. A.; Megdal, Sharon; Oroz Ramos, L. A.; Rangel Medina, Miguel; Leenhouts, James M.

2016-01-01

The United States and Mexico share waters in a number of hydrological basins and aquifers that cross the international boundary. Both countries recognize that, in a region of scarce water resources and expanding populations, a greater scientific understanding of these aquifer systems would be beneficial. In light of this, the Mexican and U.S. Principal Engineers of the International Boundary and Water Commission (IBWC) signed the “Joint Report of the Principal Engineers Regarding the Joint Cooperative Process United States-Mexico for the Transboundary Aquifer Assessment Program" on August 19, 2009 (IBWC-CILA, 2009). This IBWC “Joint Report” serves as the framework for U.S.-Mexico coordination and dialogue to implement transboundary aquifer studies. The document clarifies several details about the program such as background, roles, responsibilities, funding, relevance of the international water treaties, and the use of information collected or compiled as part of the program. In the document, it was agreed by the parties involved, which included the IBWC, the Mexican National Water Commission (CONAGUA), the U.S. Geological Survey (USGS), and the Universities of Arizona and Sonora, to study two priority binational aquifers, one in the San Pedro River basin and the other in the Santa Cruz River basin. This report focuses on the Binational San Pedro Basin (BSPB). Reasons for the focus on and interest in this aquifer include the fact that it is shared by the two countries, that the San Pedro River has an elevated ecological value because of the riparian ecosystem that it sustains, and that water resources are needed to sustain the river, existing communities, and continued development. This study describes the aquifer’s characteristics in its binational context; however, most of the scientific work has been undertaken for many years by each country without full knowledge of the conditions on the other side of the border. The general objective of this study is to

Geological study for identifying potential aquifer zone in Pakes and Bandung Villages, Konang District, Bangkalan Region

International Nuclear Information System (INIS)

I Gde Sukadana

2010-01-01

Konang District has a problem on fresh water supply particularly in dry season. Two villages in the district, namely Pakes and Konang, are densely populated areas having agriculture activities, so available of sufficient fresh water is necessary. A fresh water source that can be developed in this area is deep groundwater source from potential aquifers. A geological study has been conducted to identify potential aquifer based on lithological aspect and geological structure. According to the regional stratigraphy. the study area consists of Tawun Formation and Ngrayong Formation. They compose of carbonaceous clay stone (the oldest rock unit), carbonaceous clay stone with sandy limestone intercalations, sandy limestone interbed with carbonaceous clay stone, tuff sandstone with clay stone intercalations, and reef limestone (the youngest) respectively. Strike and dip positions of the rocks layers are N110°E/22° - N150°E/26°, located on the south anticline axis with wavy plan to gentle slope of hilly morphology. Among the rock unit, only sandy limestone has fine sand with sub angular in shape and open pack. Qualitatively. this rock has good porosity and permeability and is enables to save and to flow subsurface water. Thus. the sandy limestone is considered as a potential zone for fresh water resources. Whereas, carbonaceous clay stone with clay grain size has low porosity and permeability, so it is potential as a cap rock. (author)

Salting it away : Saskatchewan's Petroleum Technology Research Centre is leading the study of storing CO{sub 2} in saline aquifers

Energy Technology Data Exchange (ETDEWEB)

Collison, M.

2008-10-15

This paper discussed the 5-year Aquistore project that is being conducted to assess the feasibility of continuously injecting carbon dioxide (CO{sub 2}) into saline aquifers. Conducted by the Petroleum Technology Research Centre (PTRC), the aim of the project is to develop the monitoring technologies needed to prove that the CO{sub 2} can be safely and permanently stored. The $100 million dollar project will also develop technologies needed to build the necessary infrastructure for transporting the CO{sub 2} to the aquifers. Saline aquifers contain more than 10 times the capacity of depleted oil reservoirs. It is estimated that saline aquifers in the Western Canadian Sedimentary Basin (WCSB) contain enough capacity to absorb all reported emissions in Alberta and Saskatchewan every year for the next 1000 years. CO{sub 2} injected into the aquifers will become a supercritical fluid as a result of pressure and temperature forces within the aquifer and will subsequently mineralize and remain there permanently. A dedicated pipeline will transport CO{sub 2} from a refinery in Regina to the aquifer. The project is being funded by Sustainable Development Technology Canada (SDTC), an agency whose mandate is to accelerate the entry of promising energy conservation technologies into the Canadian marketplace. It is hoped that the project will develop saline storage technologies that can be used to promote carbon sequestration in Canada. 5 figs.

Hydrology of the Claiborne aquifer and interconnection with the Upper Floridan aquifer in southwest Georgia

Science.gov (United States)

Gordon, Debbie W.; Gonthier, Gerard

2017-04-24

The U.S. Geological Survey conducted a study, in cooperation with the Georgia Environmental Protection Division, to define the hydrologic properties of the Claiborne aquifer and evaluate its connection with the Upper Floridan aquifer in southwest Georgia. The effort involved collecting and compiling hydrologic data from the aquifer in subarea 4 of southwestern Georgia. Data collected for this study include borehole geophysical logs in 7 wells, and two 72-hour aquifer tests to determine aquifer properties.The top of the Claiborne aquifer extends from an altitude of about 200 feet above the North American Vertical Datum of 1988 (NAVD 88) in Terrell County to 402 feet below NAVD 88 in Decatur County, Georgia. The base of the aquifer extends from an altitude of about 60 feet above NAVD 88 in eastern Sumter County to about 750 feet below NAVD 88 in Decatur County. Aquifer thickness ranges from about 70 feet in eastern Early County to 400 feet in Decatur County.The transmissivity of the Claiborne aquifer, determined from two 72-hour aquifer tests, was estimated to be 1,500 and 700 feet squared per day in Mitchell and Early Counties, respectively. The storage coefficient was estimated to be 0.0006 and 0.0004 for the same sites, respectively. Aquifer test data from Mitchell County indicate a small amount of leakage occurred during the test. Groundwater-flow models suggest that the source of the leakage was the underlying Clayton aquifer, which produced about 2.5 feet of drawdown in response to pumping in the Claiborne aquifer. The vertical hydraulic conductivity of the confining unit between the Claiborne and Clayton aquifers was simulated to be about 0.02 foot per day.Results from the 72-hour aquifer tests run for this study indicated no interconnection between the Claiborne and overlying Upper Floridan aquifers at the two test sites. Additional data are needed to monitor the effects that increased withdrawals from the Claiborne aquifer may have on future water resources.

SAR interferometry monitoring of subsidence in a detritic basin related to water depletion in the underlying confined carbonate aquifer (Torremolinos, southern Spain).

Science.gov (United States)

Ruiz-Constán, A; Ruiz-Armenteros, A M; Martos-Rosillo, S; Galindo-Zaldívar, J; Lazecky, M; García, M; Sousa, J J; Sanz de Galdeano, C; Delgado-Blasco, J M; Jiménez-Gavilán, P; Caro-Cuenca, M; Luque-Espinar, J A

2018-04-30

This research underlines the need to improve water management policies for areas linked to confined karstic aquifers subjected to intensive exploitation, and to develop additional efforts towards monitoring their subsidence evolution. We analyze subsidence related to intensive use of groundwater in a confined karstic aquifer, through the use of the InSAR technique, by the southern coast of Spain (Costa del Sol). Carbonates are overlain by an unconfined detritic aquifer with interlayered high transmissivity rocks, in connection with the Mediterranean Sea, where the water level is rather stable. Despite this, an accumulated deformation in the line-of-sight (LOS) direction greater than -100 mm was observed by means of the ERS-1/2 (1992-2000) and Envisat (2003-2009) satellite SAR sensors. During this period, the Costa del Sol experienced a major population increase due to the expansion of the tourism industry, with the consequent increase in groundwater exploitation. The maximum LOS displacement rates recorded during both time spans are respectively -6 mm/yr and -11 mm/yr, respectively. During the entire period, there was an accumulated descent of the confined water level of 140 m, and several fluctuations of more than 80 m correlating with the subsidence trend observed for the whole area. Main sedimentary depocenters (up to 800 m), revealed by gravity prospecting, partly coincide with areas of subsidence maxima; yet ground deformation is also influenced by other factors, the main ones being the fine-grained facies distribution and rapid urbanization due to high touristic pressure. Copyright © 2018 Elsevier B.V. All rights reserved.

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...

Identifying and characterizing transboundary aquifers along the Mexico-US border: An initial assessment

Science.gov (United States)

Sanchez, Rosario; Lopez, Victoria; Eckstein, Gabriel

2016-04-01

The transboundary nature of water dividing Mexico and the United States (U.S.) transforms the entire border region into an instrument of cooperation, a source of conflict, a national security issue, and an environmental concern. Reasonable data collection and research analysis have been conducted for surface waters by joint governmental institutions and non-governmental bodies. However, with the exception of the U.S. Transboundary Assessment Act Program (TAAP) (focusing on the Hueco Bolson, Mesilla Bolson, San Pedro and Santa Cruz aquifers), there is no comparable research, institutional development, or assessment of transboundary groundwater issues on the frontier. Moreover, data collection and methodologies vary between the two countries, there is no broadly accepted definition of the transboundary nature of an aquifer, and available legal and policy frameworks are constrained by non-hydrological considerations. Hence, there is a conceptual and institutional void regarding transboundary groundwater resources between Mexico and the U.S. The purpose of this paper is to bridge this void and characterize transboundary aquifers on the Mexico-US border. It reviews existing international frameworks for identifying hydrological and social criteria that characterize an aquifer as transboundary. It then assesses data from both countries to propose where and which aquifers could be considered transboundary. Finally, the paper proposes an agenda for assessing Mexico-US transboundary aquifers as a means for improving groundwater management in the border region.

Potentiometric Surface in the Sparta-Memphis Aquifer of the Mississippi Embayment, Spring 2007

Science.gov (United States)

Schrader, T.P.

2008-01-01

The most widely used aquifer for industry and public supply in the Mississippi embayment in Arkansas, Louisiana, Mississippi, and Tennessee is the Sparta-Memphis aquifer. Decades of pumping from the Sparta-Memphis aquifer have affected ground-water levels throughout the Mississippi embayment. Regional assessments of water-level data from the aquifer are important to document regional water-level conditions and to develop a broad view of the effects of ground-water development and management on the sustainability and availability of the region's water supply. This information is useful to identify areas of water-level declines, identify cumulative areal declines that may cross State boundaries, evaluate the effectiveness of ground-water management strategies practiced in different States, and identify areas with substantial data gaps that may preclude effective management of ground-water resources. A ground-water flow model of the northern Mississippi embayment is being developed by the Mississippi Embayment Regional Aquifer Study (MERAS) to aid in answering questions about ground-water availability and sustainability. The MERAS study area covers parts of eight states including Alabama, Arkansas, Illinois, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee and covers approximately 70,000 square miles. The U.S. Geological Survey (USGS) and the Mississippi Department of Environmental Quality Office of Land and Water Resources measured water levels in wells completed in the Sparta-Memphis aquifer in the spring of 2007 to assist in the MERAS model calibration and to document regional water-level conditions. Measurements by the USGS and the Mississippi Department of Environmental Quality Office of Land and Water Resources were done in cooperation with the Arkansas Natural Resources Commission; the Arkansas Geological Survey; Memphis Light, Gas and Water; Shelby County, Tennessee; and the city of Germantown, Tennessee. In 2005, total water use from the Sparta

Southeast Regional Carbon Sequestration Partnership

Energy Technology Data Exchange (ETDEWEB)

Kenneth J. Nemeth

2006-08-30

The Southeast Regional Carbon Sequestration Partnership's (SECARB) Phase I program focused on promoting the development of a framework and infrastructure necessary for the validation and commercial deployment of carbon sequestration technologies. The SECARB program, and its subsequent phases, directly support the Global Climate Change Initiative's goal of reducing greenhouse gas intensity by 18 percent by the year 2012. Work during the project's two-year period was conducted within a ''Task Responsibility Matrix''. The SECARB team was successful in accomplishing its tasks to define the geographic boundaries of the region; characterize the region; identify and address issues for technology deployment; develop public involvement and education mechanisms; identify the most promising capture, sequestration, and transport options; and prepare action plans for implementation and technology validation activity. Milestones accomplished during Phase I of the project are listed below: (1) Completed preliminary identification of geographic boundaries for the study (FY04, Quarter 1); (2) Completed initial inventory of major sources and sinks for the region (FY04, Quarter 2); (3) Completed initial development of plans for GIS (FY04, Quarter 3); (4) Completed preliminary action plan and assessment for overcoming public perception issues (FY04, Quarter 4); (5) Assessed safety, regulatory and permitting issues (FY05, Quarter 1); (6) Finalized inventory of major sources/sinks and refined GIS algorithms (FY05, Quarter 2); (7) Refined public involvement and education mechanisms in support of technology development options (FY05, Quarter 3); and (8) Identified the most promising capture, sequestration and transport options and prepared action plans (FY05, Quarter 4).

Potential yields of wells in unconsolidated aquifers in upstate New York--Hudson-Mohawk sheet

Science.gov (United States)

Bugliosi, Edward F.; Trudell, Ruth A.; Casey, George D.

1988-01-01

This map shows the location and potential well yields of unconsolidated aquifers in the Hudson-Mohawk region at a scale of 1:250,000. It also delineates segments of aquifers that are heavily used by community water systems and designated by the New York State Department of Environmental Conservation as ' Primary Water Supply ' aquifers, and cites published reports that give detailed information on each area. Most aquifers were deposited in low-lying areas such as valleys or plains during deglaciations of the region. Thick, permeable, well-sorted sand and gravel deposits generally yield large quantities of water, greater than 100 gal/min. Thin sand, sand and gravel deposits, or thicker gravel units that have a large content of silt and fine sand, yield moderate amounts of water, 10 to 100 gal/min. Wells dug in till and those drilled in bedrock commonly yield less than 10 gal/min. (USGS)

Potential yields of wells in unconsolidated aquifers in upstate New York--lower Hudson sheet

Science.gov (United States)

Bugliosi, Edward F.; Trudell, Ruth A.

1988-01-01

This map shows the location and potential well yields from unconsolidated aquifers in the lower-Hudson region at a 1:250 ,000 scale. It also delineates segments of aquifers that are heavily used by community water systems and designated by the New York State Department of Environmental Conservation as ' Primary water supply ' aquifers and cites published reports that give detailed information on each area. Most aquifers were deposited in low-lying areas such as valleys or plains during deglaciation of the region. Thick, permeable, well-sorted sand and gravel deposits generally yield large quantities of water, more than 100 gal/min. Thin sand, sand and gravel deposits, or thicker gravel units that have a large content of silt and fine sand, yield moderate amounts of water, 10 to 100 gal/min. Wells dug in till and those drilled in bedrock commonly yield less than 10 gal/min. (USGS)

Estimating the uncertainty of the impact of climate change on alluvial aquifers. Case study in central Italy

Science.gov (United States)

Romano, Emanuele; Camici, Stefania; Brocca, Luca; Moramarco, Tommaso; Pica, Federico; Preziosi, Elisabetta

2014-05-01

There is evidence that the precipitation pattern in Europe is trending towards more humid conditions in the northern region and drier conditions in the southern and central-eastern regions. However, a great deal of uncertainty concerns how the changes in precipitations will have an impact on water resources, particularly on groundwater, and this uncertainty should be evaluated on the basis of that coming from 1) future climate scenarios of Global Circulation Models (GCMs) and 2) modeling chains including the downscaling technique, the infiltration model and the calibration/validation procedure used to develop the groundwater flow model. With the aim of quantifying the uncertainty of these components, the Valle Umbra porous aquifer (Central Italy) has been considered as a case study. This aquifer, that is exploited for human consumption and irrigation, is mainly fed by the effective infiltration from the ground surface and partly by the inflow from the carbonate aquifers bordering the valley. A numerical groundwater flow model has been developed through the finite difference MODFLOW2005 code and it has been calibrated and validated considering the recharge regime computed through a Thornthwaite-Mather infiltration model under the climate conditions observed in the period 1956-2012. Future scenarios (2010-2070) of temperature and precipitation have been obtained from three different GMCs: ECHAM-5 (Max Planck Institute, Germany), PCM (National Centre Atmospheric Research) and CCSM3 (National Centre Atmospheric Research). Each scenario has been downscaled (DSC) to the data of temperature and precipitation collected in the baseline period 1960-1990 at the stations located in the study area through two different statistical techniques (linear rescaling and quantile mapping). Then, stochastic rainfall and temperature time series are generated through the Neyman-Scott Rectangular Pulses model (NSRP) for precipitation and the Fractionally Differenced ARIMA model (FARIMA

The groundwater budget: A tool for preliminary estimation of the hydraulic connection between neighboring aquifers

Science.gov (United States)

Viaroli, Stefano; Mastrorillo, Lucia; Lotti, Francesca; Paolucci, Vittorio; Mazza, Roberto

2018-01-01

Groundwater management authorities usually use groundwater budget calculations to evaluate the sustainability of withdrawals for different purposes. The groundwater budget calculation does not always provide reliable information, and it must often be supported by further aquifer monitoring in the case of hydraulic connections between neighboring aquifers. The Riardo Plain aquifer is a strategic drinking resource for more than 100,000 people, water storage for 60 km2 of irrigated land, and the source of a mineral water bottling plant. Over a long period, the comparison between the direct recharge and the estimated natural outflow and withdrawals highlights a severe water deficit of approximately 40% of the total groundwater outflow. A groundwater budget deficit should be a clue to the aquifer depletion, but the results of long-term water level monitoring allowed the observation of the good condition of this aquifer. In fact, in the Riardo Plain, the calculated deficit is not comparable to the aquifer monitoring data acquired in the same period (1992-2014). The small oscillations of the groundwater level and the almost stable streambed spring discharge allows the presumption of an additional aquifer recharge source. The confined carbonate aquifer locally mixes with the above volcanic aquifer, providing an externally stable recharge that reduces the effects of the local rainfall variability. The combined approach of the groundwater budget results and long-term aquifer monitoring (spring discharge and/or hydraulic head oscillation) provides information about significant external groundwater exchanges, even if unidentified by field measurements, and supports the stakeholders in groundwater resource management.

Geohydrologic units and water-level conditions in the Terrace alluvial aquifer and Paluxy Aquifer, May 1993 and February 1994, near Air Force Plant 4, Fort Worth area, Texas

Science.gov (United States)

Rivers, Glen A.; Baker, Ernest T.; Coplin, L.S.

1996-01-01

The terrace alluvial aquifer underlying Air Force Plant 4 and the adjacent Naval Air Station (formerly Carswell Air Force Base) in the Fort Worth area, Texas, is contaminated locally with organic and metal compounds. Residents south and west of Air Force Plant 4 and the Naval Air Station are concerned that contaminants might enter the underlying Paluxy aquifer, which provides water to the city of White Settlement, south of Air Force Plant 4, and to residents west of Air Force Plant 4. The U.S. Environmental Protection Agency has qualified Air Force Plant 4 for Superfund cleanup. The pertinent geologic units include -A~rom oldest to youngest the Glen Rose, Paluxy, and Walnut Formations, Goodland Limestone, and terrace alluvial deposits. Except for the Glen Rose Formation, all units crop out at or near Air Force Plant 4 and the Naval Air Station. The terrace alluvial deposits, which nearly everywhere form the land surface, range from 0 to about 60 feet thick. These deposits comprise a mostly unconsolidated mixture of gravel, sand, silt, and clay. Mudstone and sandstone of the Paluxy Formation crop out north, west, and southwest of Lake Worth and total between about 130 and about 175 feet thick. The terrace alluvial deposits and the Paluxy Formation comprise the terrace alluvial aquifer and the Paluxy aquifer, respectively. These aquifers are separated by the Goodland-Walnut confining unit, composed of the Goodland Limestone and (or) Walnut Formation. Below the Paluxy aquifer, the Glen Rose Formation forms the Glen Rose confining unit. Water-level measurements during May 1993 and February 1994 from wells in the terrace alluvial aquifer indicate that, regionally, ground water flows toward the east-southeast beneath Air Force Plant 4 and the Naval Air Station. Locally, water appears to flow outward from ground-water mounds maintained by the localized infiltration of precipitation and reportedly by leaking water pipes and sanitary and (or) storm sewer lines beneath the

Lattice Boltzmann methods applied to large-scale three-dimensional virtual cores constructed from digital optical borehole images of the karst carbonate Biscayne aquifer in southeastern Florida

Science.gov (United States)

Sukop, Michael C.; Cunningham, Kevin J.

2014-11-01

Digital optical borehole images at approximately 2 mm vertical resolution and borehole caliper data were used to create three-dimensional renderings of the distribution of (1) matrix porosity and (2) vuggy megaporosity for the karst carbonate Biscayne aquifer in southeastern Florida. The renderings based on the borehole data were used as input into Lattice Boltzmann methods to obtain intrinsic permeability estimates for this extremely transmissive aquifer, where traditional aquifer test methods may fail due to very small drawdowns and non-Darcian flow that can reduce apparent hydraulic conductivity. Variogram analysis of the borehole data suggests a nearly isotropic rock structure at lag lengths up to the nominal borehole diameter. A strong correlation between the diameter of the borehole and the presence of vuggy megaporosity in the data set led to a bias in the variogram where the computed horizontal spatial autocorrelation is strong at lag distances greater than the nominal borehole size. Lattice Boltzmann simulation of flow across a 0.4 × 0.4 × 17 m (2.72 m3 volume) parallel-walled column of rendered matrix and vuggy megaporosity indicates a high hydraulic conductivity of 53 m s-1. This value is similar to previous Lattice Boltzmann calculations of hydraulic conductivity in smaller limestone samples of the Biscayne aquifer. The development of simulation methods that reproduce dual-porosity systems with higher resolution and fidelity and that consider flow through horizontally longer renderings could provide improved estimates of the hydraulic conductivity and help to address questions about the importance of scale.

Diagnosis of the Ghiss Nekor aquifer in order to elaborate the aquifer contract

Science.gov (United States)

Baite, Wissal; Boukdir, A.; Zitouni, A.; Dahbi, S. D.; Mesmoudi, H.; Elissami, A.; Sabri, E.; Ikhmerdi, H.

2018-05-01

The Ghiss-Nekor aquifer, located in the north-east of the action area of the ABHL, plays a strategic role in the drinkable water supply of the city of Al Hoceima and of the neighboring urban areas. It also participates in the irrigation of PMH. However, this aquifer has problems such as over-exploitation and pollution. In the face of these problems, the only Solution is the establishment of a new mode of governance, which privileges the participation, the involvement and the responsibility of the actors concerned in a negotiated contractual framework, namely the aquifer contract. The purpose of this study is to diagnose the current state of the Ghiss Nekor aquifer, the hydrogeological characterization of the aquifer, the use of the waters of the aquifer, the Problem identification and the introduction of the aquifer contract, which aims at the participatory and sustainable management of underground water resources in the Ghiss- Nekor plain, to ensure sustainable development.

The hydrogeochemical and isotopic investigations of the two-layered Shiraz aquifer in the northwest of Maharlou saline lake, south of Iran

Science.gov (United States)

Tajabadi, Mehdi; Zare, Mohammad; Chitsazan, Manouchehr

2018-03-01

Maharlou saline lake is the outlet of Shiraz closed basin in southern Iran, surrounded by several disconnected alluvial fresh water aquifers. These aquifers in the west and northwest of the lake are recharged by karstic anticlines such as Kaftarak in the north and Barmshour in the south. Here groundwater salinity varies along the depth so that better quality water is located below brackish or saline waters. The aim of this study is to investigate the reason for the salinity anomaly and the origin of the fresher groundwater in lower depth. Hence, the change in groundwater salinity along depth has been investigated by means of a set of geoelectrical, hydrogeological, hydrogeochemical, and environmental isotopes data. The interpretation of geoelectrical profiles and hydrogeological data indicates that the aquifer in the southeast of Shiraz plain is a two-layer aquifer separated by a fine-grained (silt and clay) layer with an approximate thickness of 40 m at the depth of about 100-120 m. Hydrgeochemistry showed that the shallow aquifer is recharged by Kaftarak karstic anticline and is affected by the saline lake water. The lake water fraction varies in different parts from zero for shallow aquifer close to the karstic anticlines to ∼70 percent in the margin of the lake. The deep aquifer is protected from the intrusion of saline lake water due to the presence of the above-mentioned confining layer with lake water fraction of zero. The stable isotopes signatures also indicate that the 'fresh' groundwater belonging to the deep aquifer is not subject to severe evaporation or mixing which is typical of the karstic water of the area. It is concluded that the characteristics of the deep aquifer are similar to those of the karstic carbonate aquifer. This karstic aquifer is most probably the Barmshour carbonated anticline buried under the shallow aquifer in the southern part. It may also be the extension of the Kaftarak anticline in the northern part.

Geochemical Impacts of Leaking CO2 from Subsurface Storage Reservoirs to Unconfined and Confined Aquifers

Energy Technology Data Exchange (ETDEWEB)

Qafoku, Nikolla; Brown, Christopher F.; Wang, Guohui; Sullivan, E. C.; Lawter, Amanda R.; Harvey, Omar R.; Bowden, Mark

2013-04-15

Experimental research work has been conducted and is undergoing at Pacific Northwest National Laboratory (PNNL) to address a variety of scientific issues related with the potential leaks of the carbon dioxide (CO2) gas from deep storage reservoirs. The main objectives of this work are as follows: • Develop a systematic understanding of how CO2 leakage is likely to influence pertinent geochemical processes (e.g., dissolution/precipitation, sorption/desorption and redox reactions) in the aquifer sediments. • Identify prevailing environmental conditions that would dictate one geochemical outcome over another. • Gather useful information to support site selection, risk assessment, policy-making, and public education efforts associated with geological carbon sequestration. In this report, we present results from experiments conducted at PNNL to address research issues related to the main objectives of this effort. A series of batch and column experiments and solid phase characterization studies (quantitative x-ray diffraction and wet chemical extractions with a concentrated acid) were conducted with representative rocks and sediments from an unconfined, oxidizing carbonate aquifer, i.e., Edwards aquifer in Texas, and a confined aquifer, i.e., the High Plains aquifer in Kansas. These materials were exposed to a CO2 gas stream simulating CO2 gas leaking scenarios, and changes in aqueous phase pH and chemical composition were measured in liquid and effluent samples collected at pre-determined experimental times. Additional research to be conducted during the current fiscal year will further validate these results and will address other important remaining issues. Results from these experimental efforts will provide valuable insights for the development of site-specific, generation III reduced order models. In addition, results will initially serve as input parameters during model calibration runs and, ultimately, will be used to test model predictive capability and

Ground-water quality assessment of the central Oklahoma Aquifer, Oklahoma; project description

Science.gov (United States)

Christenson, S.C.; Parkhurst, D.L.

1987-01-01

In April 1986, the U.S. Geological Survey began a pilot program to assess the quality of the Nation's surface-water and ground-water resources. The program, known as the National Water-Quality Assessment (NAWQA) program, is designed to acquire and interpret information about a variety of water-quality issues. The Central Oklahoma aquifer project is one of three ground-water pilot projects that have been started. The NAWQA program also incudes four surface-water pilot projects. The Central Oklahoma aquifer project, as part of the pilot NAWQA program, will develop and test methods for performing assessments of ground-water quality. The objectives of the Central Oklahoma aquifer assessment are: (1) To investigate regional ground-water quality throughout the aquifer in the manner consistent with the other pilot ground-water projects, emphasizing the occurrence and distribution of potentially toxic substances in ground water, including trace elements, organic compounds, and radioactive constituents; (2) to describe relations between ground-water quality, land use, hydrogeology, and other pertinent factors; and (3) to provide a general description of the location, nature, and possible causes of selected prevalent water-quality problems within the study unit; and (4) to describe the potential for water-quality degradation of ground-water zones within the study unit. The Central Oklahoma aquifer, which includes in descending order the Garber Sandstone and Wellington Formation, the Chase Group, the Council Grove Group, the Admire Group, and overlying alluvium and terrace deposits, underlies about 3,000 square miles of central Oklahoma and is used extensively for municipal, industrial, commercial, and domestic water supplies. The aquifer was selected for study by the NAWQA program because it is a major source for water supplies in central Oklahoma and because it has several known or suspected water-quality problems. Known problems include concentrations of arsenic, chromium

Plume Migration of Different Carbon Dioxide Phases During Geological Storage in Deep Saline Aquifers

Directory of Open Access Journals (Sweden)

Chien-Hao Shen

2015-01-01

Full Text Available This study estimates the plume migration of mobile supercritical phase (flowing, aqueous phase (dissolved, and ionic phase CO2 (bicarbonate, and evaluates the spatial distribution of immobile supercritical phase (residual and mineral phase CO2 (carbonates when CO2 was sequestered. This utilized a simulation, in an anticline structure of a deep saline aquifer in the Tiechenshan (TCS field, Taiwan. All of the trapping mechanisms and different CO2 phases were studied using the fully coupled geochemical equation-of-state GEM compositional simulator. The mobile supercritical phase CO2 moved upward and then accumulated in the up-dip of the structure because of buoyancy. A large amount of immobile supercritical phase CO2 was formed at the rear of the moving plume where the imbibition process prevailed. Both the aqueous and ionic phase CO2 finally accumulated in the down-dip of the structure because of convection. The plume volume of aqueous phase CO2 was larger than that of the supercritical phase CO2, because the convection process increased vertical sweep efficiency. The up-dip of the structure was not the major location for mineralization, which is different from mobile supercritical phase CO2 accumulation.

Processes of water rock interaction in the Turonian aquifer of Oum Er-Rabia Basin, Morocco

Science.gov (United States)

Ettazarini, Said

2005-12-01

Possible water rock interaction processes, in the Moroccan basin of Oum Er-Rabia, were discussed by a geochemical study of groundwater from the Turonian limestone aquifer, the most important water resource in the region. Different types of water according to the classification of Piper were defined. Waters have shown an evolution from dominant CHO3 Ca Mg type through mixed to SO4 Cl Ca Mg type. The use of geochemical diagrams and chemical speciation modeling method has shown that water rock interaction is mainly controlled by carbonate and anhydrite dissolution, ion exchange and reverse ion exchange processes. Water rock equilibrium conditions are favorable for the precipitation of calcite, dolomite, kaolinite and magnesian smectite.

Development Report on the Idaho National Laboratory Sitewide Three-Dimensional Aquifer Model

Energy Technology Data Exchange (ETDEWEB)

Thomas R. Wood; Catherine M. Helm-Clark; Hai Huang; Swen Magnuson; Travis McLing; Brennon Orr; Michael J. Rohe; Mitchell A. Plummer; Robert Podgorney; Erik Whitmore; Michael S. Roddy

2007-09-01

A sub-regional scale, three-dimensional flow model of the Snake River Plain Aquifer was developed to support remediation decisions for Waste Area Group 10, Operable Unit 10 08 at the Idaho National Laboratory (INL) Site. This model has been calibrated primarily to water levels and secondarily to groundwater velocities interpreted from stable isotope disequilibrium studies and the movement of anthropogenic contaminants in the aquifer from facilities at the INL. The three-dimensional flow model described in this report is one step in the process of constructing a fully three-dimensional groundwater flow and contaminant transport model as prescribed in the Idaho National Engineering and Environmental Laboratory Operable Unit 10-08 Sitewide Groundwater Model Work Plan. An updated three-dimensional hydrogeologic conceptual model is presented along with the geologic basis for the conceptual model. Sediment-dominated three-dimensional volumes were used to represent the geology and constrain groundwater flow as part of the conceptual model. Hydrological, geochemical, and geological data were summarized and evaluated to infer aquifer behavior. A primary observation from development and evaluation of the conceptual model was that relative to flow on a regional scale, the aquifer can be treated with steady-state conditions. Boundary conditions developed for the three-dimensional flow model are presented along with inverse simulations that estimate parameterization of hydraulic conductivity. Inverse simulations were performed using the pilot-point method to estimate permeability distributions. Thermal modeling at the regional aquifer scale and at the sub-regional scale using the inverted permeabilities is presented to corroborate the results of the flow model. The results from the flow model show good agreement with simulated and observed water levels almost always within 1 meter. Simulated velocities show generally good agreement with some discrepancies in an interpreted low

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

Directory of Open Access Journals (Sweden)

Andrea Sottani

2014-09-01

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

Chapter 9: Carbon fluxes across regions.

Science.gov (United States)

Beverly E. Law; Dave Turner; John Campbell; Michael Lefsky; Michael Guzy; Osbert Sun; Steve Van Tuyl; Warren Cohen

2006-01-01

Scaling biogeochemical processes to regions, continents, and the globe is critical for understanding feedbacks between the biosphere and atmosphere in the analysis of global change. This includes the effects of changing atmospheric carbon dioxide, climate, disturbances, and increasing nitrogen deposition from air pollution (Ehleringer and Field 1993, Vitousek et al....

Palaeoclimatic trends deduced from the hydrochemistry of a Triassic sandstone aquifer, United Kingdom

International Nuclear Information System (INIS)

Bath, A.H.; Edmunds, W.M.; Andrews, J.N.

1979-01-01

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. 14 C activity and delta 13 C values show downgradient decrease and increase, respectively, the latter from -12 to -13 per mille (PDB) at outcrop to -8.5 per mille in deep confined groundwaters, indicating a continuing reaction between water and carbonate mineral phases. Although the bulk carbonate contained in sandstone samples gives delta 13 C around -7 per mille, modelling of the carbon isotopic evolution and consideration of the resulting 14 C age corrections suggest that a carbonate with delta 13 C closer to 0 per mille has played a major role in at least the earlier stages of hydrochemical evolution. The corrected radiocarbon age ranges, generated by the computer program WATEQF-ISOTOP, are used as a framework in which the palaeo-environmental information from oxygen and hydrogen isotope data, inert gas contents, and chloride levels are discussed. The measurement of dissolved helium levels demonstrates an excess of 4 He in many samples, which correlates with radiocarbon ages. The assumption of bulk chemical and physical properties for the aquifer rock allows independent 'excess 4 He' ages to be computed, which are mostly in excess of the corrected 14 C ages. The trend of delta 18 O is from about -8 per mille at outcrop to -9.7 per mille (SMOW) downgradient, which is significantly more depleted than has been found in previous studies of UK basins. The delta 2 H and delta 18 O values are related by the regression line delta 2 H=6.6delta 18 O+1; data from other UK studies also lie close to this trend

Combining hydrologic and groundwater modelling to characterize a regional aquifer system within a rift setting (Gidabo River Basin, Main Ethiopian Rift)

Science.gov (United States)

Birk, Steffen; Mechal, Abraham; Wagner, Thomas; Dietzel, Martin; Leis, Albrecht; Winkler, Gerfried; Mogessie, Aberra

2016-04-01

The development of groundwater resources within the Ethiopian Rift is complicated by the strong physiographic contrasts between the rift floor and the highland and by the manifold hydrogeological setting composed of volcanic rocks of different type and age that are intersected by numerous faults. Hydrogeochemical and isotope data from various regions within the Ethiopian Rift suggest that the aquifers within the semi-arid rift floor receive a significant contribution of groundwater flow from the humid highland. For example, the major ion composition of groundwater samples from Gidabo River Basin (3302 km²) in the southern part of the Main Ethiopian Rift reveals a mixing trend from the highland toward the rift floor; moreover, the stable isotopes of water, deuterium and O-18, of the rift-floor samples indicate a component recharged in the highland. This work aims to assess if the hydrological and hydrogeological data available for Gidabo River Basin is consistent with these findings and to characterize the regional aquifer system within the rift setting. For this purpose, a two-step approach is employed: First, the semi-distributed hydrological model SWAT is used to obtain an estimate of the spatial and temporal distribution of groundwater recharge within the watershed; second, the numerical groundwater flow model MODFLOW is employed to infer aquifer properties and groundwater flow components. The hydrological model was calibrated and validated using discharge data from three stream gauging stations within the watershed (Mechal et al., Journal of Hydrology: Regional Studies, 2015, doi:10.1016/j.ejrh.2015.09.001). The resulting recharge distribution exhibits a strong decrease from the highland, where the mean annual recharge amounts to several hundred millimetres, to the rift floor, where annual recharge largely is around 100 mm and below. Using this recharge distribution as input, a two-dimensional steady-state groundwater flow model was calibrated to hydraulic

PGDP Trichloroethene Biodegradation Investigation Summary Report: Regional Gravel Aquifer & Northwest Plume

Energy Technology Data Exchange (ETDEWEB)

Hampson, Steve [Univ. of Kentucky, Lexington, KY (United States). Kentucky Research Consortium for Energy and Environment

2008-09-01

The evaluation of biological degradation processes addressed by this report are part of a broad trichloroethene (TCE) Fate and Transport Investigation that includes four (4) topics of phased investigation (Table ES1) relative to degradation and/or attenuation of TCE in the Regional Gravel Aquifer (RGA) underlying the United States Department of Energy Paducah Gaseous Diffusion Plant (PGDP). In order of implementation the project phases are: (1) derivation of a TCE first-order rate constant by normalization of TCE values against technetium-99 (⁹⁹Tc) and chloride. 2) identification of the presence of microbes capable of aerobic co-metabolic TCE biodegradation using enzyme activity probes (this report); 3) Compound-specific isotope analysis (CSIA) to support prevalence of biotic and/or abiotic degradation processes; and 4) evaluation of potential abiotic RGA-TCE attenuation mechanisms including sorption. This report summarizes the Phase II activities related to the identification and evaluation of biological degradation processes that may be actively influencing TCE fate and transport in the RGA contaminant plumes at the United States Department of Energy (DOE) PGDP and its environs (Figure ES1). The goals of these activities were to identify active biological degradation mechanisms in the RGA through multiple lines of evidence and to provide DOE with recommendations for future TCE biological degradation investigations.

Air Quality Co-Benefits of a Carbon Policy: Regional Implementation

Science.gov (United States)

Thompson, T. M.; Rausch, S.; Saari, R.; Selin, N. E.

2013-12-01

We use an integrated modeling framework to assess the air quality influence of climate change policies in the Northeast U.S. states for air pollution, and their relative health and economic benefits. We analyze three carbon policy scenarios, each reducing the same total amount of GHG emissions in the Northeast United States: an economy-wide Cap and Trade (CAT) program reducing emissions from all sectors of the economy, a Clean Energy Scenario (CES) reducing emissions from the electricity sector only, and a Transportation Scenario (TRN) reducing emissions from the transportation sector only. Regional CES policy and a regional TRN policy will cost about 10 times and 50 times more than a CAT policy, respectively. Regional CAT policy will lead to a 6% greater reduction in carbon emissions nationally in the year 2030 compared to an electric or transportation sector cap with the same regional targets. This is because, unlike a total economy cap, targeted policy options will likely cause increases in carbon emissions outside of the region covered (called carbon leakage). The human health benefits of the CAT, CES and TRN policies are 530%, 118%, and 10% of the costs of each policy respectively, meaning that the CAT and CES policies will likely fully pay for themselves in the NE U.S. We estimate that the value of human health co-benefits associated with reductions of ground level ozone and particulate matter of the CES scenario is twice that of the CAT and TRN scenarios. Economic welfare costs for each of three regionally applied carbon emissions reduction scenario are shown in blue. The calculated dollar amount of the human health benefits point estimate is shown in red with the 95% confidence interval, associated with human health response only, shown using the green line. Values are in billions of year 2006 US dollars.

Arsenic release during managed aquifer recharge (MAR)

Science.gov (United States)

Pichler, T.; Lazareva, O.; Druschel, G.

2013-12-01

The mobilization and addition of geogenic trace metals to groundwater is typically caused by anthropogenic perturbations of the physicochemical conditions in the aquifer. This can add dangerously high levels of toxins to groundwater, thus compromising its use as a source of drinking water. In several regions world-wide, aquifer storage and recovery (ASR), a form of managed aquifer recharge (MAR), faces the problem of arsenic release due to the injection of oxygenated storage water. To better understand this process we coupled geochemical reactive transport modeling to bench-scale leaching experiments to investigate and verify the mobilization of geogenic arsenic (As) under a range of redox conditions from an arsenic-rich pyrite bearing limestone aquifer in Central Florida. Modeling and experimental observations showed similar results and confirmed the following: (1) native groundwater and aquifer matrix, including pyrite, were in chemical equilibrium, thus preventing the release of As due to pyrite dissolution under ambient conditions; (2) mixing of oxygen-rich surface water with oxygen-depleted native groundwater changed the redox conditions and promoted the dissolution of pyrite, and (3) the behavior of As along a flow path was controlled by a complex series of interconnected reactions. This included the oxidative dissolution of pyrite and simultaneous sorption of As onto neo-formed hydrous ferric oxides (HFO), followed by the reductive dissolution of HFO and secondary release of adsorbed As under reducing conditions. Arsenic contamination of drinking water in these systems is thus controlled by the re-equilibration of the system to more reducing conditions rather than a purely oxidative process.

CO{sub 2} storage in saline aquifers; Stockage du CO{sub 2} dans les aquiferes salins

Energy Technology Data Exchange (ETDEWEB)

Bentham, M.; Kirby, G. [British Geological Survey (BGS), Kingsley Dunham Centre, Keyworth, Nottingham (United Kingdom)

2005-06-01

Saline aquifers represent a promising way for CO{sub 2} sequestration. Storage capacities of saline aquifers are very important around the world. The Sleipner site in the North Sea is currently the single case world-wide of CO{sub 2} storage in a saline aquifer. A general review is given on the specific risks for CO{sub 2} storage in saline aquifer. The regional distribution of CO{sub 2} storage potential is presented. Finally, the knowledge gaps and the future research in this field are defined. (authors)

Case studies of groundwater- surface water interactions and scale relationships in small alluvial aquifers

NARCIS (Netherlands)

Love, Dave; de Hamer, Wouter; Owen, Richard J.S.; Booij, Martijn J.; Uhlenbrook, Stefan; Hoekstra, Arjen Ysbert; van der Zaag, Pieter

2007-01-01

An alluvial aquifer can be described as a groundwater system, generally unconfined, that is hosted in laterally discontinuous layers of gravel, sand, silt and clay, deposited by a river in a river channel, banks or flood plain. In semi-arid regions, streams that are associated with alluvial aquifers

Delineating fresh water and brackish water aquifers by GIS and groundwater quality data

International Nuclear Information System (INIS)

Yasin, M.; Latif, M.

2007-01-01

This study was conducted in the Mona project area, Bhalwal, district Sargodha to delineate fresh water and brackish water aquifers by GIS (Geographic Information System) and historic groundwater quality data of 138 deep tube wells installed in the study area. The groundwater quality zonations were made by overlapping maps of TDS (Total Dissolved Solids), SAR (Sodium Adsorption Ratio) and RSC (Residual Sodium Carbonate). Seven zones of groundwater quality consisting of good, marginal, hazardous and their combinations were identified. The results indicated redistribution of salts in the aquifer and rise in water table in some parts of the study area from 1965-1997. (author)

Mapping groundwater level and aquifer storage variations from InSAR measurements in the Madrid aquifer, Central Spain

Science.gov (United States)

Béjar-Pizarro, Marta; Ezquerro, Pablo; Herrera, Gerardo; Tomás, Roberto; Guardiola-Albert, Carolina; Ruiz Hernández, José M.; Fernández Merodo, José A.; Marchamalo, Miguel; Martínez, Rubén

2017-04-01

Groundwater resources are under stress in many regions of the world and the future water supply for many populations, particularly in the driest places on Earth, is threatened. Future climatic conditions and population growth are expected to intensify the problem. Understanding the factors that control groundwater storage variation is crucial to mitigate its adverse consequences. In this work, we apply satellite-based measurements of ground deformation over the Tertiary detritic aquifer of Madrid (TDAM), Central Spain, to infer the spatio-temporal evolution of water levels and estimate groundwater storage variations. Specifically, we use Persistent Scatterer Interferometry (PSI) data during the period 1992-2010 and piezometric time series on 19 well sites covering the period 1997-2010 to build groundwater level maps and quantify groundwater storage variations. Our results reveal that groundwater storage loss occurred in two different periods, 1992-1999 and 2005-2010 and was mainly concentrated in a region of ∼200 km2. The presence of more compressible materials in that region combined with a long continuous water extraction can explain this volumetric deficit. This study illustrates how the combination of PSI and piezometric data can be used to detect small aquifers affected by groundwater storage loss helping to improve their sustainable management.

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.

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.

Groundwater nitrate pollution and climate change: learnings from a water balance-based analysis of several aquifers in a western Mediterranean region (Catalonia).

Science.gov (United States)

Mas-Pla, Josep; Menció, Anna

2018-04-11

Climate change will affect the dynamics of the hydrogeological systems and their water resources quality; in particular nitrate, which is herein taken as a paradigmatic pollutant to illustrate the effects of climate change on groundwater quality. Based on climatic predictions of temperature and precipitation for the horizon of 2021 and 2050, as well as on land use distribution, water balances are recalculated for the hydrological basins of distinct aquifer systems in a western Mediterranean region as Catalonia (NE Spain) in order to determine the reduction of available water resources. Besides the fact that climate change will represent a decrease of water availability, we qualitatively discuss the modifications that will result from the future climatic scenarios and their impact on nitrate pollution according to the geological setting of the selected aquifers. Climate effects in groundwater quality are described according to hydrological, environmental, socio-economic, and political concerns. Water reduction stands as a major issue that will control stream-aquifer interactions and subsurface recharge, leading to a general modification of nitrate in groundwater as dilution varies. A nitrate mass balance model provides a gross estimation of potential nitrate evolution in these aquifers, and it points out that the control of the fertilizer load will be crucial to achieve adequate nitrate content in groundwater. Reclaimed wastewater stands as local reliable resource, yet its amount will only satisfy a fraction of the loss of available resources due to climate change. Finally, an integrated management perspective is necessary to avoid unplanned actions from private initiatives that will jeopardize the achievement of sustainable water resources exploitation under distinct hydrological scenarios.

Contribution of piezometric measurement to knowledge and management of low water levels: examples on the chalk aquifer in the Champagne Ardennes region

Directory of Open Access Journals (Sweden)

P. Stollsteiner

2015-04-01

Full Text Available This article is based on a BRGM study on piezometric indicators, threshold values of discharge and groundwater levels for the assessment of potentially-exploitable water resources of chalky watersheds. A method for estimating low water levels based on groundwater levels is presented from three examples representing chalk aquifers with different cycles: annual, combined and interannual. The first is located in Picardy and the two others in the Champagne-Ardennes region. Piezometers with annual cycles, used in these examples, are supposed to be representative of the aquifer hydro-dynamics. Except for multi-annual systems, the analysis between discharge measurements at a hydrometric station and groundwater levels measured at a piezometer representative of the main aquifer, leads to relatively precise and satisfactory relationships within a chalky context. These relationships may be useful for monitoring, validation, extension or reconstruction of the low water flow data. On the one hand, they allow definition of the piezometric levels corresponding to the different alert thresholds of river discharges. On the other hand, they clarify the proportions of low surface water flow from runoff or drainage of the aquifer. Finally, these correlations give an assessment of the minimum flow for the coming weeks. However, these correlations cannot be used to optimize the value of the exploitable water resource because it seems to be difficult to integrate the value of the effective rainfall that could occur during the draining period. Moreover, in the case of multi-annual systems, the solution is to attempt a comprehensive system modelling and, if it is satisfactory, using the simulated values to get rid of parasites or running the model for forecasting purposes.

Contribution of piezometric measurement to knowledge and management of low water levels: examples on the chalk aquifer in the Champagne Ardennes region

Science.gov (United States)

Stollsteiner, P.; Bessiere, H.; Nicolas, J.; Allier, D.; Berthet, O.

2015-04-01

This article is based on a BRGM study on piezometric indicators, threshold values of discharge and groundwater levels for the assessment of potentially-exploitable water resources of chalky watersheds. A method for estimating low water levels based on groundwater levels is presented from three examples representing chalk aquifers with different cycles: annual, combined and interannual. The first is located in Picardy and the two others in the Champagne-Ardennes region. Piezometers with annual cycles, used in these examples, are supposed to be representative of the aquifer hydro-dynamics. Except for multi-annual systems, the analysis between discharge measurements at a hydrometric station and groundwater levels measured at a piezometer representative of the main aquifer, leads to relatively precise and satisfactory relationships within a chalky context. These relationships may be useful for monitoring, validation, extension or reconstruction of the low water flow data. On the one hand, they allow definition of the piezometric levels corresponding to the different alert thresholds of river discharges. On the other hand, they clarify the proportions of low surface water flow from runoff or drainage of the aquifer. Finally, these correlations give an assessment of the minimum flow for the coming weeks. However, these correlations cannot be used to optimize the value of the exploitable water resource because it seems to be difficult to integrate the value of the effective rainfall that could occur during the draining period. Moreover, in the case of multi-annual systems, the solution is to attempt a comprehensive system modelling and, if it is satisfactory, using the simulated values to get rid of parasites or running the model for forecasting purposes.

Quantification of the reactions in heat storage systems in the Malm aquifer

Science.gov (United States)

Ueckert, Martina; Baumann, Thomas

2017-04-01

Combined heat and power plants (CHP) are efficient and environmentally friendly because excess heat produced during power generation is used for heating purposes. While the power demand remains rather constant throughout the year, the heat demand shows seasonal variations. In a worst-case scenario, the heat production in winter is not sufficient, and the power production in summer has to be ramped down because the excess heat cannot be released to the environment. Therefore, storage of excess heat of CHP is highly beneficial from an economic and an ecological point of view. Aquifer thermal energy storage (ATES) is considered as a promising technology for energy storage. In a typical setting, water from an aquifer is produced, heated up by excess heat from the CHP and injected through a second borehole back into the aquifer. The carbonate rocks of the upper Jurrasic in the Molasse Basin seem to be promising sites for aquifer heat storage because of their high transmissivity combined with a typical geological setting with tight caprock. However, reactions in the aquifer cannot be neglected and may become the limiting process of the whole operation. While there have been several studies performed in clastic aquifers and for temperatures below 100°C, the knowledge about high injection temperatures and storage into a carbonatic aquifer matrix is still limited. Within a research project funded by the Bavarian State Ministry for Economic Affairs and the BMW Group, the storage and recuperation of excess heat energy into the Bavarian Malm aquifer with flow rates of 15 L/s and temperatures of up to 110°C was investigated. The addition of {CO_2} was used to prevent precipitations. Data from the field site was backed up by autoclave experiments and used to verify a conceptional hydrogeochemical model with PhreeqC for the heat storage operation. The model allows to parametrize the operation and to predict possible reactions in the aquifer.

Groundwater Flow Systems at the Nevada Test Site, Nevada: A Synthesis of Potentiometric Contours, Hydrostratigraphy, and Geologic Structures

Energy Technology Data Exchange (ETDEWEB)

Fenelon, Joseph M.; Sweetkind, Donald S.; Laczniak, Randell J.

2010-01-25

Contaminants introduced into the subsurface of the Nevada Test Site by underground nuclear testing are of concern to the U.S. Department of Energy and regulators responsible for protecting human health and safety. The potential for contaminant movement away from the underground test areas and into the accessible environment is greatest by groundwater transport. The primary hydrologic control on this transport is evaluated and examined through a series of contour maps developed to represent the hydraulic-head distribution within each of the major aquifers underlying the area. Aquifers were identified and their extents delineated by merging and analyzing multiple hydrostratigraphic framework models developed by other investigators from existing geologic information. A map of the hydraulic-head distribution in each major aquifer was developed from a detailed evaluation and assessment of available water-level measurements. Multiple spreadsheets that accompany this report provide pertinent water-level and geologic data by well or drill hole. Aquifers are mapped and discussed in general terms as being one of two types: alluvial-volcanic, or carbonate. Both aquifer types are subdivided and mapped as independent regional and local aquifers, based on the continuity of their component rock. Groundwater-flow directions, approximated from potentiometric contours that were developed from the hydraulic-head distribution, are indicated on the maps and discussed for each of the regional aquifers and for selected local aquifers. Hydraulic heads vary across the study area and are interpreted to range in altitude from greater than 5,000 feet in a regional alluvial-volcanic aquifer beneath a recharge area in the northern part of the study area to less than 2,300 feet in regional alluvial-volcanic and carbonate aquifers in the southwestern part of the study area. Flow directions throughout the study area are dominantly south-southwest with some local deviations. Vertical hydraulic

Groundwater Flow Systems at the Nevada Test Site, Nevada: A Synthesis of Potentiometric Contours, Hydrostratigraphy, and Geologic Structures

Science.gov (United States)

Fenelon, Joseph M.; Sweetkind, Donald S.; Laczniak, Randell J.

2010-01-01

Contaminants introduced into the subsurface of the Nevada Test Site by underground nuclear testing are of concern to the U.S. Department of Energy and regulators responsible for protecting human health and safety. The potential for contaminant movement away from the underground test areas and into the accessible environment is greatest by groundwater transport. The primary hydrologic control on this transport is evaluated and examined through a series of contour maps developed to represent the hydraulic-head distribution within each of the major aquifers underlying the area. Aquifers were identified and their extents delineated by merging and analyzing multiple hydrostratigraphic framework models developed by other investigators from existing geologic information. A map of the hydraulic-head distribution in each major aquifer was developed from a detailed evaluation and assessment of available water-level measurements. Multiple spreadsheets that accompany this report provide pertinent water-level and geologic data by well or drill hole. Aquifers are mapped and discussed in general terms as being one of two types: alluvial-volcanic, or carbonate. Both aquifer types are subdivided and mapped as independent regional and local aquifers, based on the continuity of their component rock. Groundwater-flow directions, approximated from potentiometric contours that were developed from the hydraulic-head distribution, are indicated on the maps and discussed for each of the regional aquifers and for selected local aquifers. Hydraulic heads vary across the study area and are interpreted to range in altitude from greater than 5,000 feet in a regional alluvial-volcanic aquifer beneath a recharge area in the northern part of the study area to less than 2,300 feet in regional alluvial-volcanic and carbonate aquifers in the southwestern part of the study area. Flow directions throughout the study area are dominantly south-southwest with some local deviations. Vertical hydraulic

Variable exchange between a stream and an aquifer in the Rio Grande Project Area

Science.gov (United States)

Sheng, Z.; Abudu, S.; Michelsen, A.; King, P.

2016-12-01

Both surface water and groundwater in the Rio Grande Project area in southern New Mexico and Far West Texas have been stressed by natural conditions such as droughts and human activities, including urban development and agricultural irrigation. In some area pumping stress in the aquifer becomes so great that it depletes the river flow especially during the irrigation season, typically from March through October. Therefore understanding such relationship between surface water and groundwater becomes more important in regional water resources planning and management. In this area, stream flows are highly regulated by the upstream reservoirs during the irrigation season and greatly influenced by return flows during non-irrigation season. During a drought additional groundwater pumping to supplement surface water shortage further complicates the surface water and groundwater interaction. In this paper the authors will use observation data and results of numerical models (MODFLOW) to characterize and quantify hydrological exchange fluxes between groundwater in the aquifers and surface water as well as impacts of groundwater pumping. The interaction shows a very interesting seasonal variation (irrigation vs. non-irrigation) as well as impact of a drought. Groundwater has been pumped for both municipal supplies and agricultural irrigation, which has imposed stresses toward both stream flows and aquifer storage. The results clearly show that historic groundwater pumping has caused some reaches of the river change from gaining stream to losing stream. Beyond the exchange between surface water and groundwater in the shallow aquifer, groundwater pumping in a deep aquifer could also enhance the exchanges between different aquifers through leaky confining layers. In the earlier history of pumping, pumping from the shallow aquifer is compensated by simple depletion of surface water, while deep aquifer tends to use the aquifer storage. With continued pumping, the cumulative

FEWA: a Finite Element model of Water flow through Aquifers

International Nuclear Information System (INIS)

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

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.

Estimation of Hydraulic Parameters and Aquifer Properties for a Managed Aquifer Recharge Pilot Study in The Lower Mississippi River Basin

Science.gov (United States)

Ozeren, Y.; Rigby, J.; Holt, R. M.

2017-12-01

Mississippi River Valley Alluvial Aquifer (MRVAA) is the major irrigation water resource in the in the lower Mississippi River basin. MRVAA has been significantly depleted in the last two decades due to excessive pumping. A wide range of measures to ensure sustainable groundwater supply in the region is currently under investigation. One of the possible solution under consideration is to use Managed Aquifer Recharge (MAR) by artificial recharge. The proposed artificial recharge technique in this study is to collect water through bank filtration, transfer water via pipeline to the critically low groundwater areas by a set of injection wells. A pilot study in the area is underway to investigate the possibility of artificial recharge in the area. As part of this study, a pumping test was carried out on an existing irrigation well along banks of Tallahatchie River near Money, MS. Geophysical surveys were also carried out in the pilot study area. Hydraulic response of the observation wells was used to determine stream bed conductance and aquifer parameters. The collected hydraulic parameters and aquifer properties will provide inputs for small-scale, high-resolution engineering model for abstraction-injection hydraulics along river. Here, preliminary results of the pilot study is presented.

Have We Overestimated Saline Aquifer CO2 Storage Capacities?

International Nuclear Information System (INIS)

Thibeau, S.; Mucha, V.

2011-01-01

During future, large scale CO 2 geological storage in saline aquifers, fluid pressure is expected to rise as a consequence of CO 2 injection, but the pressure build up will have to stay below specified values to ensure a safe and long term containment of the CO 2 in the storage site. The pressure build up is the result of two different effects. The first effect is a local overpressure around the injectors, which is due to the high CO 2 velocities around the injectors, and which can be mitigated by adding CO 2 injectors. The second effect is a regional scale pressure build up that will take place if the storage aquifer is closed or if the formation water that flows away from the pressurised area is not large enough to compensate volumetrically the CO 2 injection. This second effect cannot be mitigated by adding additional injectors. In the first section of this paper, we review some major global and regional assessments of CO 2 storage capacities in deep saline aquifers, in term of mass and storage efficiency. These storage capacities are primarily based on a volumetric approach: storage capacity is the volumetric sum of the CO 2 that can be stored through various trapping mechanisms. We then discuss in Section 2 storage efficiencies derived from a pressure build up approach, as stated in the CO2STORE final report (Chadwick A. et al. (eds) (2008) Best Practice for the Storage of CO 2 in Saline Aquifers, Observations and Guidelines from the SACS and CO2STORE Projects, Keyworth, Nottingham, BGS Occasional Publication No. 14) and detailed by Van der Meer and Egberts (van der Meer L.G.H., Egberts P.J.P. (2008) A General Method for Calculating Subsurface CO 2 Storage Capacity, OTC Paper 19309, presented at the OTC Conference held in Houston, Texas, USA, 5-8 May). A quantitative range of such storage efficiency is presented, based on a review of orders of magnitudes of pore and water compressibilities and allowable pressure increase. To illustrate the relevance of this

The Ozark Plateaus Regional Aquifer Study—Documentation of a groundwater-flow model constructed to assess water availability in the Ozark Plateaus

Science.gov (United States)

Clark, Brian R.; Richards, Joseph M.; Knierim, Katherine J.

2018-03-30

moving into or out of storage in the aquifer system resulting in changes in modeled groundwater levels.The goal of the model was to develop a model capable of suitable accuracy at regional scales. The intent was not to reproduce individual local-scale details, which are typically not possible given the uniform cell size of 1 square mile. Although the model may not represent each local-scale detail, the model can be applied for a better understanding of the regional flow system and to evaluate responses to changes in climate and groundwater pumping.

Workshop on assessments of National Carbon Budgets within the Nordic Region

DEFF Research Database (Denmark)

Hansen, Kristina; Koyama, Aki; Lansø, Anne Sofie

The three-day workshop organized by the three Nordic research projects; ECOCLIM, LAGGE and SnowCarbo brought together scientists and other actors from Nordic countries to communicate and discuss research on carbon budget estimations in the Nordic region. Through presentations of most recent...... research in the field and following scientific discussions, the workshop contributed to strengthen the scientific basis of the identification and quantification of major natural carbon sinks in the Nordic region on which integrated climate change abatement and management strategies and policy decisions...... status and knowledge on research on assessments of national carbon budgets as well as on projections and sensitivity to future changes in e.g. management and climate change in the Nordic Region....

Workshop on assessments of National Carbon Budgets within the Nordic Region

DEFF Research Database (Denmark)

Mørk, Eva Thorborg; Lansø, Anne Sofie; Hansen, Kristina

2013-01-01

The three-day workshop organized by the three Nordic research projects; ECOCLIM, LAGGE and SnowCarbo brought together scientists and other actors from Nordic countries to communicate and discuss research on carbon budget estimations in the Nordic region. Through presentations of most recent...... research in the field and following scientific discussions, the workshop contributed to strengthen the scientific basis of the identification and quantification of major natural carbon sinks in the Nordic region on which integrated climate change abatement and management strategies and policy decisions...... status and knowledge on research on assessments of national carbon budgets as well as on projections and sensitivity to future changes in e.g. management and climate change in the Nordic Region....

Estimating the carbon budget and maximizing future carbon uptake for a temperate forest region in the U.S.

Science.gov (United States)

2012-01-01

Background Forests of the Midwest U.S. provide numerous ecosystem services. Two of these, carbon sequestration and wood production, are often portrayed as conflicting. Currently, carbon management and biofuel policies are being developed to reduce atmospheric CO2 and national dependence on foreign oil, and increase carbon storage in ecosystems. However, the biological and industrial forest carbon cycles are rarely studied in a whole-system structure. The forest system carbon balance is the difference between the biological (net ecosystem production) and industrial (net emissions from forest industry) forest carbon cycles, but to date this critical whole system analysis is lacking. This study presents a model of the forest system, uses it to compute the carbon balance, and outlines a methodology to maximize future carbon uptake in a managed forest region. Results We used a coupled forest ecosystem process and forest products life cycle inventory model for a regional temperate forest in the Midwestern U.S., and found the net system carbon balance for this 615,000 ha forest was positive (2.29 t C ha-1 yr-1). The industrial carbon budget was typically less than 10% of the biological system annually, and averaged averaged 0.082 t C ha-1 yr-1. Net C uptake over the next 100-years increased by 22% or 0.33 t C ha-1 yr-1 relative to the current harvest rate in the study region under the optized harvest regime. Conclusions The forest’s biological ecosystem current and future carbon uptake capacity is largely determined by forest harvest practices that occurred over a century ago, but we show an optimized harvesting strategy would increase future carbon sequestration, or wood production, by 20-30%, reduce long transportation chain emissions, and maintain many desirable stand structural attributes that are correlated to biodiversity. Our results for this forest region suggest that increasing harvest over the next 100 years increases the strength of

Estimating the carbon budget and maximizing future carbon uptake for a temperate forest region in the U.S.

Directory of Open Access Journals (Sweden)

Peckham Scott D

2012-06-01

Full Text Available Abstract Background Forests of the Midwest U.S. provide numerous ecosystem services. Two of these, carbon sequestration and wood production, are often portrayed as conflicting. Currently, carbon management and biofuel policies are being developed to reduce atmospheric CO2 and national dependence on foreign oil, and increase carbon storage in ecosystems. However, the biological and industrial forest carbon cycles are rarely studied in a whole-system structure. The forest system carbon balance is the difference between the biological (net ecosystem production and industrial (net emissions from forest industry forest carbon cycles, but to date this critical whole system analysis is lacking. This study presents a model of the forest system, uses it to compute the carbon balance, and outlines a methodology to maximize future carbon uptake in a managed forest region. Results We used a coupled forest ecosystem process and forest products life cycle inventory model for a regional temperate forest in the Midwestern U.S., and found the net system carbon balance for this 615,000 ha forest was positive (2.29 t C ha-1 yr-1. The industrial carbon budget was typically less than 10% of the biological system annually, and averaged averaged 0.082 t C ha-1 yr-1. Net C uptake over the next 100-years increased by 22% or 0.33 t C ha-1 yr-1 relative to the current harvest rate in the study region under the optized harvest regime. Conclusions The forest’s biological ecosystem current and future carbon uptake capacity is largely determined by forest harvest practices that occurred over a century ago, but we show an optimized harvesting strategy would increase future carbon sequestration, or wood production, by 20-30%, reduce long transportation chain emissions, and maintain many desirable stand structural attributes that are correlated to biodiversity. Our results for this forest region suggest that increasing harvest over the next 100�

Interactive effects of environmental change and management strategies on regional forest carbon emissions.

Science.gov (United States)

Hudiburg, Tara W; Luyssaert, Sebastiaan; Thornton, Peter E; Law, Beverly E

2013-11-19

Climate mitigation activities in forests need to be quantified in terms of the long-term effects on forest carbon stocks, accumulation, and emissions. The impacts of future environmental change and bioenergy harvests on regional forest carbon storage have not been quantified. We conducted a comprehensive modeling study and life-cycle assessment of the impacts of projected changes in climate, CO2 concentration, and N deposition, and region-wide forest management policies on regional forest carbon fluxes. By 2100, if current management strategies continue, then the warming and CO2 fertilization effect in the given projections result in a 32-68% increase in net carbon uptake, overshadowing increased carbon emissions from projected increases in fire activity and other forest disturbance factors. To test the response to new harvesting strategies, repeated thinnings were applied in areas susceptible to fire to reduce mortality, and two clear-cut rotations were applied in productive forests to provide biomass for wood products and bioenergy. The management strategies examined here lead to long-term increased carbon emissions over current harvesting practices, although semiarid regions contribute little to the increase. The harvest rates were unsustainable. This comprehensive approach could serve as a foundation for regional place-based assessments of management effects on future carbon sequestration by forests in other locations.

Aquifer thermal-energy-storage modeling

Science.gov (United States)

Schaetzle, W. J.; Lecroy, J. E.

1982-09-01

A model aquifer was constructed to simulate the operation of a full size aquifer. Instrumentation to evaluate the water flow and thermal energy storage was installed in the system. Numerous runs injecting warm water into a preconditioned uniform aquifer were made. Energy recoveries were evaluated and agree with comparisons of other limited available data. The model aquifer is simulated in a swimming pool, 18 ft by 4 ft, which was filled with sand. Temperature probes were installed in the system. A 2 ft thick aquifer is confined by two layers of polyethylene. Both the aquifer and overburden are sand. Four well configurations are available. The system description and original tests, including energy recovery, are described.

Simulated effects of groundwater withdrawals from the Kirkwood-Cohansey aquifer system and Piney Point aquifer, Maurice and Cohansey River Basins, Cumberland County and vicinity, New Jersey

Science.gov (United States)

Gordon, Alison D.; Buxton, Debra E.

2018-05-10

groundwater demand in 2050 at municipal public-supply wells; and (5) estimated 2050 monthly groundwater demand at municipal public-supply wells for which pumping of selected municipal public-supply wells was moved to a deeper part of the Kirkwood-Cohansey aquifer system. The results of the baseline scenario (scenario 1) were used for comparison with the results of scenarios 2‒5.The results of scenarios 2‒3 indicate that simulated water-level declines occurred in the Cohansey River Basin when full-allocation groundwater withdrawals were incorporated (scenarios 2 and 3). In scenarios 2 and 3, full-allocation withdrawals in the Cohansey River Basin were approximately 266 and 407 percent greater, respectively, than in the baseline scenario. In scenario 2, the largest decline in simulated water levels was more than 67 ft in June and September of scenario year 11, whereas in scenario 3, simulated water levels declined as much as 90 ft in June and more than 100 ft in September of scenario year 11. These simulated declines occurred in a small area around one pumped well in the Cohansey River Basin. The average decline in simulated water levels for this basin was less than 10 ft for scenario 2 and less than 20 ft for scenario 3. In scenario 2, the Menantico Creek subbasin in the Maurice River Basin had a decrease in base flow during about 29 percent of the 11-year simulation period, and in scenario 3, the decrease occurred during about 71 percent of the 11-year simulation period. In scenario 3, base flow in the Cohansey River Basin was less than the 7-day 10-year low flow in all months of simulation years 7 through 11. Several agricultural-irrigation wells and a number of public-supply wells are within the Cohansey River Basin and the Menantico Creek subbasin.Three additional scenarios were simulated to evaluate the possible use of the Piney Point aquifer in the Cumberland County study area using the New Jersey Regional Aquifer-System Analysis model, which incorporates all

Assessment of Brine Management for Geologic Carbon Sequestration

Energy Technology Data Exchange (ETDEWEB)

Breunig, Hanna M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Birkholzer, Jens T. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Borgia, Andrea [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Price, Phillip N. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Oldenburg, Curtis M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; McKone, Thomas E. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division

2013-06-13

reluctant to invest in capital intensive, high risk GCS projects; early technical, economic, and environmental assessments of brine management are extremely valuable for determining the potential role of GCS in the US. We performed a first order feasibility and economic assessment, at three different locations in the US, of twelve GCS extracted-­water management options, including: geothermal energy extraction, desalination, salt and mineral harvesting, rare-­earth element harvesting, aquaculture, algae biodiesel production, road de-­icing, enhanced geothermal system (EGS) recharge, underground reinjection, landfill disposal, ocean disposal, and evaporation pond disposal. Three saline aquifers from different regions of the US were selected as hypothetical GCS project sites to encompass variation in parameters that are relevant to the feasibility and economics of brine disposal. The three aquifers are the southern Mt. Simon Sandstone Formation in the Illinois Basin, IL; the Vedder Formation in the southern San Joaquin Basin, CA; and the Jasper Interval in the eastern Texas Gulf Basin, TX. These aquifers are candidates for GCS due to their physical characteristics and their close proximity to large CO₂ emission sources. Feasibility and impacts were calculated using one mt-­CO₂ injected as the functional unit of brine management. Scenarios were performed for typical 1000MW coal-­fired power plants (CFPP) that incurred an assumed 24 percent carbon capture energy penalty (EP), injected 90 percent of CO₂ emissions (~9 million mt-­ CO₂ injected annually), and treated extracted water onsite. Net present value (NPV), land requirements, laws and regulations, and technological limits were determined for each stage of disposal, and used to estimate feasibility. The boundary of the assessment began once extracted water was brought to the surface, and ended once the water evaporated, was injected underground, or was discharged into

Discourse characteristics of ore-bearing aquifer of Chaidenghao in Husiliang area

International Nuclear Information System (INIS)

Zhou Bowen

2012-01-01

Call Sri Lanka article focuses primarily on wood board beam region trench features lots of ore-bearing aquifer, located in the ore-bearing aquifer under Zhiluo lower sub-section; A brief introduction to the work area's geology and stratigraphic structure, and a brief description of the main ore purpose of the lower layer Zhiluo under sub-section lithology; Shows aquifer top, bottom and described its characteristics, the two formed a 'watertight-water-impermeable' good hydrogeological structure of the ancient interlayer oxidation zone formation to create a favorable space. Based on the above description and analysis of the location of uranium mineralization in good condition, have a good vision of the mineralization. (author)

Isotopic and hydro geochemistry study of the granular aquifer from Comarca Lagunera, Mexico

International Nuclear Information System (INIS)

Gonzalez Hita, Luis; Sanchez Diaz, Luis Felipe

1994-01-01

The Comarca Lagunera is one of Mexico's biggest agricultural regions. Its water sources are the Nazas and Aguanaval Rivers and a quaternary granular aquifer. The over exploitation of the aquifer has led to deteriorated groundwater quality due to the presence of arsenic. This study aims to determine the origin and evolution of the arsenic and to update the system's hydrogeochemical information. The methodology used is based on an analysis of the physical framework and on the hydrogeochemical and isotope characterization of the groundwater. An interpretation of the results shows that the arsenic could have originated in two geological events: first, the magmatic processes that generated the region's intrusive and extrusive igneous rocks, and second, the sedimentation of alluvial-lacustrine materials bearing arsenic, which were transported by the Nazas and Aguanaval Rivers during the aquifer's formation. (author)

Biochemical indicators for the bioavailability of organic carbon in ground water

Science.gov (United States)

Chapelle, F.H.; Bradley, P.M.; Goode, D.J.; Tiedeman, C.; Lacombe, P.J.; Kaiser, K.; Benner, R.

2009-01-01

The bioavailability of total organic carbon (TOC) was examined in ground water from two hydrologically distinct aquifers using biochemical indicators widely employed in chemical oceanography. Concentrations of total hydrolyzable neutral sugars (THNS), total hydrolyzable amino acids (THAA), and carbon-normalized percentages of TOC present as THNS and THAA (referred to as "yields") were assessed as indicators of bioavailability. A shallow coastal plain aquifer in Kings Bay, Georgia, was characterized by relatively high concentrations (425 to 1492 ??M; 5.1 to 17.9 mg/L) of TOC but relatively low THNS and THAA yields (???0.2%-1.0%). These low yields are consistent with the highly biodegraded nature of TOC mobilized from relatively ancient (Pleistocene) sediments overlying the aquifer. In contrast, a shallow fractured rock aquifer in West Trenton, New Jersey, exhibited lower TOC concentrations (47 to 325 ??M; 0.6 to 3.9 mg/L) but higher THNS and THAA yields (???1% to 4%). These higher yields were consistent with the younger, and thus more bioavailable, TOC being mobilized from modern soils overlying the aquifer. Consistent with these apparent differences in TOC bioavailability, no significant correlation between TOC and dissolved inorganic carbon (DIC), a product of organic carbon mineralization, was observed at Kings Bay, whereas a strong correlation was observed at West Trenton. In contrast to TOC, THNS and THAA concentrations were observed to correlate with DIC at the Kings Bay site. These observations suggest that biochemical indicators such as THNS and THAA may provide information concerning the bioavailability of organic carbon present in ground water that is not available from TOC measurements alone.

Threshold amounts of organic carbon needed to initiate reductive dechlorination in groundwater systems

Science.gov (United States)

Chapelle, Francis H.; Thomas, Lashun K.; Bradley, Paul M.; Rectanus, Heather V.; Widdowson, Mark A.

2012-01-01

Aquifer sediment and groundwater chemistry data from 15 Department of Defense facilities located throughout the United States were collected and analyzed with the goal of estimating the amount of natural organic carbon needed to initiate reductive dechlorination in groundwater systems. Aquifer sediments were analyzed for hydroxylamine and NaOH-extractable organic carbon, yielding a probable underestimate of potentially bioavailable organic carbon (PBOC). Aquifer sediments were also analyzed for total organic carbon (TOC) using an elemental combustion analyzer, yielding a probable overestimate of bioavailable carbon. Concentrations of PBOC correlated linearly with TOC with a slope near one. However, concentrations of PBOC were consistently five to ten times lower than TOC. When mean concentrations of dissolved oxygen observed at each site were plotted versus PBOC, it showed that anoxic conditions were initiated at approximately 200 mg/kg of PBOC. Similarly, the accumulation of reductive dechlorination daughter products relative to parent compounds increased at a PBOC concentration of approximately 200 mg/kg. Concentrations of total hydrolysable amino acids (THAA) in sediments also increased at approximately 200 mg/kg, and bioassays showed that sediment CO2 production correlated positively with THAA. The results of this study provide an estimate for threshold amounts of bioavailable carbon present in aquifer sediments (approximately 200 mg/kg of PBOC; approximately 1,000 to 2,000 mg/kg of TOC) needed to support reductive dechlorination in groundwater systems.

Survival of bacterial indicators and the functional diversity of native microbial communities in the Floridan aquifer system, south Florida

Science.gov (United States)

Lisle, John T.

2014-01-01

The Upper Floridan aquifer in the southern region of Florida is a multi-use, regional scale aquifer that is used as a potable water source and as a repository for passively recharged untreated surface waters, and injected treated surface water and wastewater, industrial wastes, including those which contain greenhouse gases (for example, carbon dioxide). The presence of confined zones within the Floridan aquifer that range in salinity from fresh to brackish allow regulatory agencies to permit the injection of these different types of product waters into specific zones without detrimental effects to humans and terrestrial and aquatic ecosystems. The type of recharge that has received the most regulatory attention in south Florida is aquifer storage and recovery (ASR). The treated water, prior to injection and during recovery, must meet primary and secondary drinking water standards. The primary microbiology drinking water standard is total coliforms, which have been shown to be difficult to inactivate below the regulatory standard during the treatment process at some ASR facilities. The inefficient inactivation of this group of indicator bacteria permits their direct injection into the storage zones of the Floridan aquifer. Prior to this study, the inactivation rates for any member of the total coliform group during exposure to native geochemical conditions in groundwater from any zone of the Floridan aquifer had not been derived. Aboveground flow through mesocosms and diffusion chambers were used to quantify the inactivation rates of two bacterial indicators, Escherichia coli and Pseudomonas aeruginosa, during exposure to groundwater from six wells. These wells collect water from two ASR storage zones: the Upper Floridan aquifer (UFA) and Avon Park Permeable Zone (APPZ). Both bacterial strains followed a biphasic inactivation model. The E. coli populations had slower inactivation rates in the UFA (range: 0.217–0.628 per hour (h-1)) during the first phase of the

Arsenic release from shallow aquifers of the Hetao basin, Inner Mongolia: evidence from bacterial community in aquifer sediments and groundwater.

Science.gov (United States)