WorldWideScience

Sample records for melton valley groundwater

  1. Wetland survey of the X-10 Bethel Valley and Melton Valley groundwater operable units at Oak Ridge National Labortory Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    Rosensteel, B.A.

    1996-03-01

    Executive Order 11990, Protection of Wetlands, (May 24, 1977) requires that federal agencies avoid, to the extent possible, adverse impacts associated with the destruction and modification of wetlands and that they avoid direct and indirect support of wetlands development when there is a practicable alternative. In accordance with Department of Energy (DOE) Regulations for Compliance with Floodplains and Wetlands Environmental Review Requirements (Subpart B, 10 CFR 1022.11), surveys for wetland presence or absence were conducted in both the Melton Valley and the Bethel Valley Groundwater Operable Units (GWOU) on the DOE Oak Ridge Reservation (ORR) from October 1994 through September 1995. As required by the Energy and Water Development Appropriations Act of 1992, wetlands were identified using the criteria and methods set forth in the Wetlands Delineation Manual (Army Corps of Engineers, 1987). Wetlands were identified during field surveys that examined and documented vegetation, soils, and hydrologic evidence. Most of the wetland boundary locations and wetland sizes are approximate. Boundaries of wetlands in Waste Area Grouping (WAG) 2 and on the former proposed site of the Advanced Neutron Source in the upper Melton Branch watershed were located by civil survey during previous wetland surveys; thus, the boundary locations and areal sizes in these areas are accurate. The wetlands were classified according to the system developed by Cowardin et al. (1979) for wetland and deepwater habitats of the United States. A total of 215 individual wetland areas ranging in size from 0.002 ha to 9.97 ha were identified in the Bethel Valley and Melton Valley GWOUs. The wetlands are classified as palustrine forested broad-leaved deciduous (PFO1), palustrine scrub-shrub broad-leaved deciduous (PSS1), and palustrine persistent emergent (PEM1)

  2. Wetland survey of the X-10 Bethel Valley and Melton Valley groundwater operable units at Oak Ridge National Labortory Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    Rosensteel, B.A.

    1996-03-01

    Executive Order 11990, Protection of Wetlands, (May 24, 1977) requires that federal agencies avoid, to the extent possible, adverse impacts associated with the destruction and modification of wetlands and that they avoid direct and indirect support of wetlands development when there is a practicable alternative. In accordance with Department of Energy (DOE) Regulations for Compliance with Floodplains and Wetlands Environmental Review Requirements (Subpart B, 10 CFR 1022.11), surveys for wetland presence or absence were conducted in both the Melton Valley and the Bethel Valley Groundwater Operable Units (GWOU) on the DOE Oak Ridge Reservation (ORR) from October 1994 through September 1995. As required by the Energy and Water Development Appropriations Act of 1992, wetlands were identified using the criteria and methods set forth in the Wetlands Delineation Manual (Army Corps of Engineers, 1987). Wetlands were identified during field surveys that examined and documented vegetation, soils, and hydrologic evidence. Most of the wetland boundary locations and wetland sizes are approximate. Boundaries of wetlands in Waste Area Grouping (WAG) 2 and on the former proposed site of the Advanced Neutron Source in the upper Melton Branch watershed were located by civil survey during previous wetland surveys; thus, the boundary locations and areal sizes in these areas are accurate. The wetlands were classified according to the system developed by Cowardin et al. (1979) for wetland and deepwater habitats of the United States. A total of 215 individual wetland areas ranging in size from 0.002 ha to 9.97 ha were identified in the Bethel Valley and Melton Valley GWOUs. The wetlands are classified as palustrine forested broad-leaved deciduous (PFO1), palustrine scrub-shrub broad-leaved deciduous (PSS1), and palustrine persistent emergent (PEM1).

  3. Wetland Survey of the X-10 Bethel Valley and Melton Valley Groundwater Operable Units at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    Rosensteel, B.

    1993-01-01

    This wetland survey report regarding wetlands within Melton Valley and Bethel Valley areas of the Oak Ridge Reservation was prepared in accordance with requirements under the Comprehensive Environmental Response, Compensation, and Liability Act for reporting the results of a site characterization for public review. This work was done under Work Breakdown Structure number 1.4.12.6.1.15.41. This document provides the Environmental Restoration program with information on the results of the wetland survey conducted during fiscal year 1995. it includes information on the physical characteristics, location, approximate size, and classification of wetland areas identified during the field survey.

  4. Remedial investigation report on the Melton Valley watershed at Oak Ridge National Laboratory, Oak Ridge, Tennessee. Volume 3: Appendix C

    International Nuclear Information System (INIS)

    1997-05-01

    The Melton Valley watershed presents a multifaceted management and decision-making challenge because of the very heterogeneous conditions that exist with respect to contaminant type, disposal unit age, mode of disposal, release mechanism, and potential risk-producing pathways. The investigation presented here has assembled relevant site data in the geographic context with the intent of enabling program managers and decision-makers to understand site conditions and evaluate the necessity, relative priority, and scope of potential remedial actions. The industrial and recreational exposure scenarios are used to provide a risk assessment reference context to evaluate levels of contamination in surface water, groundwater, soil, and sediment within each subbasin of the Melton Valley watershed. All available analytical results for the media of interest that could be qualified for use in the risk assessment were screened to determine carcinogenic risk values and noncarcinogenic hazard indexes and to identify the chemicals of concern (COCs) for each evaluated media in each subbasin

  5. Remedial investigation report on the Melton Valley watershed at Oak Ridge National Laboratory, Oak Ridge, Tennessee. Volume 3: Appendix C

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-05-01

    The Melton Valley watershed presents a multifaceted management and decision-making challenge because of the very heterogeneous conditions that exist with respect to contaminant type, disposal unit age, mode of disposal, release mechanism, and potential risk-producing pathways. The investigation presented here has assembled relevant site data in the geographic context with the intent of enabling program managers and decision-makers to understand site conditions and evaluate the necessity, relative priority, and scope of potential remedial actions. The industrial and recreational exposure scenarios are used to provide a risk assessment reference context to evaluate levels of contamination in surface water, groundwater, soil, and sediment within each subbasin of the Melton Valley watershed. All available analytical results for the media of interest that could be qualified for use in the risk assessment were screened to determine carcinogenic risk values and noncarcinogenic hazard indexes and to identify the chemicals of concern (COCs) for each evaluated media in each subbasin.

  6. Development of a three-dimensional groundwater flow model for Western Melton Valley: Application of P-FEM on a DOE waste site

    Energy Technology Data Exchange (ETDEWEB)

    West, O.R.; Toran, L.E.

    1994-04-01

    Modeling the movement of hazardous waste in groundwater was identified by the US Department of Energy (DOE) as one of the grand challenges in scientific computation. In recognition of this need, DOE has provided support for a group of scientists from several national laboratories and universities to conduct research and development in groundwater flow and contaminant transport modeling. This group is part of a larger consortium of researchers, collectively referred to as the Partnership in Computational Science (PICS), that has been charged with the task of applying high-performance computational tools and techniques to grand challenge areas identified by DOE. One of the goals of the PICS Groundwater Group is to develop a new three-dimensional groundwater flow and transport code that is optimized for massively parallel computers. An existing groundwater flow code, 3DFEMWATER, was parallelized in order to serve as a benchmark for these new models. The application of P-FEM, the parallelized version of 3DFEMWATER, to a real field site is the subject of this report.

  7. Development of a three-dimensional groundwater flow model for Western Melton Valley: Application of P-FEM on a DOE waste site

    International Nuclear Information System (INIS)

    West, O.R.; Toran, L.E.

    1994-04-01

    Modeling the movement of hazardous waste in groundwater was identified by the US Department of Energy (DOE) as one of the grand challenges in scientific computation. In recognition of this need, DOE has provided support for a group of scientists from several national laboratories and universities to conduct research and development in groundwater flow and contaminant transport modeling. This group is part of a larger consortium of researchers, collectively referred to as the Partnership in Computational Science (PICS), that has been charged with the task of applying high-performance computational tools and techniques to grand challenge areas identified by DOE. One of the goals of the PICS Groundwater Group is to develop a new three-dimensional groundwater flow and transport code that is optimized for massively parallel computers. An existing groundwater flow code, 3DFEMWATER, was parallelized in order to serve as a benchmark for these new models. The application of P-FEM, the parallelized version of 3DFEMWATER, to a real field site is the subject of this report

  8. Oak Ridge National Laboratory Melton Valley Storage Tanks Waste Filtration Process Evaluation

    International Nuclear Information System (INIS)

    Walker, B.W.

    1998-01-01

    Cross-flow filtration is being evaluated as a pretreatment in the proposed treatment processes for aqueous high-level radioactive wastes at Oak Ridge National Laboratory (ORNL) to separate insoluble solids from aqueous waste from the Melton Valley Storage Tanks (MVST)

  9. Remedial investigation report on the Melton Valley watershed at Oak Ridge National Laboratory, Oak Ridge, Tennessee. Volume 2: Appendixes A and B

    International Nuclear Information System (INIS)

    1997-05-01

    The Melton Valley watershed presents a multifaceted management and decision-making challenge because of the very heterogeneous conditions that exist with respect to contaminant type, disposal unit age, mode of disposal, release mechanism, and potential risk-producing pathways. The investigation presented here has assembled relevant site data in the geographic context with the intent of enabling program managers and decision-makers to understand site conditions and evaluate the necessity, relative priority, and scope of potential remedial actions. The industrial and recreational exposure scenarios are used to provide a risk assessment reference context to evaluate levels of contamination in surface water, groundwater, soil, and sediment within each subbasin of the Melton Valley watershed. All available analytical results for the media of interest that could be qualified for use in the risk assessment were screened to determine carcinogenic risk values and noncarcinogenic hazard indexes and to identify the chemicals of concern (COCs) for each evaluated media in each subbasin

  10. Remedial investigation report on the Melton Valley watershed at Oak Ridge National Laboratory, Oak Ridge, Tennessee. Volume 2: Appendixes A and B

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-05-01

    The Melton Valley watershed presents a multifaceted management and decision-making challenge because of the very heterogeneous conditions that exist with respect to contaminant type, disposal unit age, mode of disposal, release mechanism, and potential risk-producing pathways. The investigation presented here has assembled relevant site data in the geographic context with the intent of enabling program managers and decision-makers to understand site conditions and evaluate the necessity, relative priority, and scope of potential remedial actions. The industrial and recreational exposure scenarios are used to provide a risk assessment reference context to evaluate levels of contamination in surface water, groundwater, soil, and sediment within each subbasin of the Melton Valley watershed. All available analytical results for the media of interest that could be qualified for use in the risk assessment were screened to determine carcinogenic risk values and noncarcinogenic hazard indexes and to identify the chemicals of concern (COCs) for each evaluated media in each subbasin.

  11. Melton Valley Storage Tanks Capacity Increase Project, Oak Ridge National Laboratory, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    1995-04-01

    The US Department of Energy (DOE) proposes to construct and maintain additional storage capacity at Oak Ridge National Laboratory (ORNL), Oak Ridge, Tennessee, for liquid low-level radioactive waste (LLLW). New capacity would be provided by a facility partitioned into six individual tank vaults containing one 100,000 gallon LLLW storage tank each. The storage tanks would be located within the existing Melton Valley Storage Tank (MVST) facility. This action would require the extension of a potable water line approximately one mile from the High Flux Isotope Reactor (HFIR) area to the proposed site to provide the necessary potable water for the facility including fire protection. Alternatives considered include no-action, cease generation, storage at other ORR storage facilities, source treatment, pretreatment, and storage at other DOE facilities

  12. Melton Valley Storage Tanks Capacity Increase Project, Oak Ridge National Laboratory, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-04-01

    The US Department of Energy (DOE) proposes to construct and maintain additional storage capacity at Oak Ridge National Laboratory (ORNL), Oak Ridge, Tennessee, for liquid low-level radioactive waste (LLLW). New capacity would be provided by a facility partitioned into six individual tank vaults containing one 100,000 gallon LLLW storage tank each. The storage tanks would be located within the existing Melton Valley Storage Tank (MVST) facility. This action would require the extension of a potable water line approximately one mile from the High Flux Isotope Reactor (HFIR) area to the proposed site to provide the necessary potable water for the facility including fire protection. Alternatives considered include no-action, cease generation, storage at other ORR storage facilities, source treatment, pretreatment, and storage at other DOE facilities.

  13. Radiological assessment of worker doses during sludge mobilization and removal at the Melton Valley storage tanks

    International Nuclear Information System (INIS)

    Kerr, G.D.; Coleman, R.L.; Kocher, D.C.; Wynn, C.C.

    1996-01-01

    This report presents an assessment of potential radiation doses to workers during mobilization and removal of contaminated sludges from the Melton Valley Storage Tanks at Oak Ridge National Laboratory. The assessment is based on (1) measurements of radionuclide concentrations in sludge and supernatant liquid samples from the waste storage tanks, (2) measurements of gamma radiation levels in various areas that will be accessed by workers during normal activities, (3) calculations of gamma radiation levels for particular exposure situations, especially when the available measurements are not applicable, and (4) assumed scenarios for worker activities in radiation areas. Only doses from external exposure are estimated in this assessment. Doses from internal exposure are assumed to be controlled by containment of radioactive materials or respiratory protection of workers and are not estimated

  14. Radiological assessment of worker doses during sludge mobilization and removal at the Melton Valley storage tanks

    Energy Technology Data Exchange (ETDEWEB)

    Kerr, G.D.; Coleman, R.L.; Kocher, D.C.; Wynn, C.C.

    1996-12-17

    This report presents an assessment of potential radiation doses to workers during mobilization and removal of contaminated sludges from the Melton Valley Storage Tanks at Oak Ridge National Laboratory. The assessment is based on (1) measurements of radionuclide concentrations in sludge and supernatant liquid samples from the waste storage tanks, (2) measurements of gamma radiation levels in various areas that will be accessed by workers during normal activities, (3) calculations of gamma radiation levels for particular exposure situations, especially when the available measurements are not applicable, and (4) assumed scenarios for worker activities in radiation areas. Only doses from external exposure are estimated in this assessment. Doses from internal exposure are assumed to be controlled by containment of radioactive materials or respiratory protection of workers and are not estimated.

  15. Cesium removal demonstration utilizing crystalline silicotitanate sorbent for processing Melton Valley Storage Tank supernate: Final report

    International Nuclear Information System (INIS)

    Walker, J.F. Jr.; Taylor, P.A.; Cummins, R.L.

    1998-03-01

    This report provides details of the Cesium Removal Demonstration (CsRD), which was conducted at Oak Ridge National Laboratory (ORNL) on radioactive waste from the Melton Valley Storage Tanks. The CsRD was the first large-scale use of state-of-the-art sorbents being developed by private industry for the selective removal of cesium and other radionuclides from liquid wastes stored across the DOE complex. The crystalline silicotitanate sorbent used in the demonstration was chosen because of its effectiveness in laboratory tests using bench-scale columns. The demonstration showed that the cesium could be removed from the supernate and concentrated on a small-volume, solid waste form that would meet the waste acceptance criteria for the Nevada Test Site. During this project, the CsRD system processed > 115,000 L (30,000 gal) of radioactive supernate with minimal operational problems. Sluicing, drying, and remote transportation of the sorbent, which could not be done on a bench scale, were successfully demonstrated. The system was then decontaminated to the extent that it could be contact maintained with the use of localized shielding only. By utilizing a modular, transportable design and placement within existing facilities, the system can be transferred to different sites for reuse. The initial unit has now been removed from the process building and is presently being reinstalled for use in baseline operations at ORNL

  16. Cesium removal demonstration utilizing crystalline silicotitanate sorbent for processing Melton Valley Storage Tank supernate: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Walker, J.F. Jr.; Taylor, P.A.; Cummins, R.L. [and others

    1998-03-01

    This report provides details of the Cesium Removal Demonstration (CsRD), which was conducted at Oak Ridge National Laboratory (ORNL) on radioactive waste from the Melton Valley Storage Tanks. The CsRD was the first large-scale use of state-of-the-art sorbents being developed by private industry for the selective removal of cesium and other radionuclides from liquid wastes stored across the DOE complex. The crystalline silicotitanate sorbent used in the demonstration was chosen because of its effectiveness in laboratory tests using bench-scale columns. The demonstration showed that the cesium could be removed from the supernate and concentrated on a small-volume, solid waste form that would meet the waste acceptance criteria for the Nevada Test Site. During this project, the CsRD system processed > 115,000 L (30,000 gal) of radioactive supernate with minimal operational problems. Sluicing, drying, and remote transportation of the sorbent, which could not be done on a bench scale, were successfully demonstrated. The system was then decontaminated to the extent that it could be contact maintained with the use of localized shielding only. By utilizing a modular, transportable design and placement within existing facilities, the system can be transferred to different sites for reuse. The initial unit has now been removed from the process building and is presently being reinstalled for use in baseline operations at ORNL.

  17. Oak Ridge National Laboratory Melton Valley Storage Tanks Waste filtration process evaluation

    International Nuclear Information System (INIS)

    Walker, B.W.; McCabe, D.J.

    1997-01-01

    The purpose of this filter study was to evaluate cross-flow filtration as effective solid-liquid separation technology for treating Oak Ridge National Laboratory wastes, outline operating conditions for equipment, examine the expected filter flow rates, and determine proper cleaning.The Gunite Tanks at the Oak Ridge National Laboratory contain heels which are a mixture of sludge, wash water, and bentonite clay. The tanks are to be cleaned out with a variety of flushing techniques and the dilute mixture transferred to another storage tank. One proposal is to transfer this mixture into existing Melton Valley Storage Tanks (MVST), which already contain a large amount of sludge and supernate. The mixed aqueous phase will then be transferred to new MVST, which are prohibited from containing insoluble solids. To separate the solid from the liquid and thereby prevent solids transfer into the new MVST, a technique is needed that can cleanly separate the sludge and bentonite clay from the supernate. One proposed method for solid liquid separation is cross-flow filtration. Cross-flow filtration has been used at the Savannah River and West Valley sites for treatment of tank waste, and is being tested for applicability at other sites. The performance of cross-flow filters with sludge has been tested, but the impact of sludge combined with bentonite clay has not. The objective of this test was to evaluate the feasibility of using cross-flow filters to perform the solid liquid separation required for the mixture of Gunite and MVST tank wastes

  18. Characterization and leaching study of sludge from Melton Valley Storage Tank W-25

    International Nuclear Information System (INIS)

    Collins, J.L.; Egan, B.Z.; Beahm, E.C.; Chase, C.W.; Anderson, K.K.

    1997-08-01

    One of the greatest challenges facing the Department of Energy (DOE) is the remediation of the 100 million gallons of high-level and low-level radioactive waste in the underground storage tanks at its Hanford, Savannah River, Oak Ridge, Idaho, and Fernald sites. Bench-scale batch tests have been conducted with sludge from the Melton Valley Storage Tank (MVST) Facility at Oak Ridge National Laboratory (ORNL) to evaluate separation processes for use in a comprehensive sludge-processing flow sheet for concentrating the radionuclides and reducing the volumes of storage tanks wastes for final disposal. This report discusses the hot cell apparatus, the characterization of the sludge, and the results obtained from a variety of basic and acidic leaching tests of samples of sludge. Approximately 5 L of sludge/supernate from MVST W-25 was retrieved and transferred to a stainless steel tank for mixing and storage in a hot cell. Samples were centrifuged to separate the sludge liquid and the sludge solids. Air-dried samples of sludge were analyzed to determine the concentrations of radionuclides, other metals, and anions. Based upon the air-dried weight, about 41% of the centrifuged, wet sludge solids was water. The major alpha-, gamma-, and beta-emitting radionuclides in the centrifuged, wet sludge solids were 137 Cs, 60 Co, 154 Eu, 241 Am, 244 Cm, 90 Sr, Pu, U, and Th. The other major metals (in addition to the U and Th) and the anions were Na, Ca, Al, K, Mg, NO 3 - , CO 3 2- , OH - , and O 2- . The organic carbon content was 3.0 ± 1.0%. The pH was 13

  19. Characterization and leaching study of sludge from Melton Valley Storage Tank W-25

    Energy Technology Data Exchange (ETDEWEB)

    Collins, J.L.; Egan, B.Z.; Beahm, E.C.; Chase, C.W.; Anderson, K.K.

    1997-08-01

    One of the greatest challenges facing the Department of Energy (DOE) is the remediation of the 100 million gallons of high-level and low-level radioactive waste in the underground storage tanks at its Hanford, Savannah River, Oak Ridge, Idaho, and Fernald sites. Bench-scale batch tests have been conducted with sludge from the Melton Valley Storage Tank (MVST) Facility at Oak Ridge National Laboratory (ORNL) to evaluate separation processes for use in a comprehensive sludge-processing flow sheet for concentrating the radionuclides and reducing the volumes of storage tanks wastes for final disposal. This report discusses the hot cell apparatus, the characterization of the sludge, and the results obtained from a variety of basic and acidic leaching tests of samples of sludge. Approximately 5 L of sludge/supernate from MVST W-25 was retrieved and transferred to a stainless steel tank for mixing and storage in a hot cell. Samples were centrifuged to separate the sludge liquid and the sludge solids. Air-dried samples of sludge were analyzed to determine the concentrations of radionuclides, other metals, and anions. Based upon the air-dried weight, about 41% of the centrifuged, wet sludge solids was water. The major alpha-, gamma-, and beta-emitting radionuclides in the centrifuged, wet sludge solids were {sup 137}Cs, {sup 60}Co, {sup 154}Eu, {sup 241}Am, {sup 244}Cm, {sup 90}Sr, Pu, U, and Th. The other major metals (in addition to the U and Th) and the anions were Na, Ca, Al, K, Mg, NO{sub 3}{sup {minus}}, CO{sub 3}{sup 2{minus}}, OH{sup {minus}}, and O{sub 2{minus}}. The organic carbon content was 3.0 {+-} 1.0%. The pH was 13.

  20. Melton Valley liquid low-level radioactive waste storage tanks evaluation

    International Nuclear Information System (INIS)

    1995-06-01

    The Melton Valley Liquid Low-Level Radioactive Waste Storage Tanks (MVSTs) store the evaporator concentrates from the Liquid Low-Level Radioactive Waste (LLLW) System at the Oak Ridge National Laboratory (ORNL). The eight stainless steel tanks contain approximately 375,000 gallons of liquid and sludge waste. These are some of the newer, better-designed tanks in the LLLW System. They have been evaluated and found by the US Environmental Protection Agency (EPA) and the Tennessee Department of Environment and Conservation to comply with all Federal Facility Agreement requirements for double containment. The operations and maintenance aspects of the tanks were also reviewed by the Defense Nuclear Facilities Safety Board (DNFSB) in September 1994. This document also contains an assessment of the risk to the public and ORNL workers from a leak in one of the MVSTs. Two primary scenarios were investigated: (1) exposure of the public to radiation from drinking Clinch River water contaminated by leaked LLLW, and (2) exposure of on-site workers to radiation by inhaling air contaminated by leaked LLLW. The estimated frequency of a leak from one of the MVSTs is about 8 x 10 -4 events per year, or about once in 1200 years (with a 95% confidence level). If a leak were to occur, the dose to a worker from inhalation would be about 2.3 x 10 -1 mrem (with a 95% confidence level). The dose to a member of the public through the drinking water pathway is estimated to be about 7 x 10 -1 mrem (with a 95% confidence level). By comparison with EPA Safe Drinking Water regulations, the allowable lifetime radiation dose is about 300 mrem. Thus, a postulated LLLW leak from the MVSTs would not add appreciably to an individual's lifetime radiation dose

  1. Fluid dynamic studies for a simulated Melton Valley Storage Tank slurry

    International Nuclear Information System (INIS)

    Hylton, T.D.; Youngblood, E.L.; Cummins, R.L.

    1994-07-01

    The Melton Valley Storage Tanks (MVSTs), are used for the collection and storage of remote-handled radioactive liquid wastes. These wastes, which were typically acidic when generated, were neutralized with the addition of sodium hydroxide to protect the storage tanks from corrosion, but this caused the transuranic and heavy metals to precipitate. These wastes will eventually need to be removed from the tanks for ultimate disposal. The objective of the research activities discussed in this report is to support the design of a pipeline transport system between the MVSTs and a treatment facility. Since the wastes in the MVSTs are highly radioactive, a surrogate slurry was developed for this study. Rheological properties of the simulated slurry were determined in a test loop in which the slurry was circulated through three pipeline viscometers of different diameters. Pressure drop data at varying flow rates were used to obtain shear stress and shear rate data. The data were analyzed, and the slurry rheological properties were analyzed by the Power Law model and the Bingham plastic model. The plastic viscosity and yield stress data obtained from the rheological tests were used as inputs for a piping design software package, and the pressure drops predicted by the software compared well with the pressure drop data obtained from the test loop. The minimum transport velocity was determine for the slurry by adding known nominal sizes of glass spheres to the slurry. However, it was shown that the surrogate slurry exhibited hindered settling, which may substantially decrease the minimum transport velocity. Therefore, it may be desired to perform additional tests with a surrogate with a lower concentration of suspended solids to determine the minimum transport velocity

  2. Surface radiological investigations along State Highway 95, Lagoon Road, and Melton Valley Drive, Oak Ridge Reservation, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    Tiner, P.F.; Uziel, M.S.; Rice, D.E.; Williams, J.K.

    1995-08-01

    The surface radiological investigation along State Highway 95, Lagoon Road, and Melton Valley Drive at the Oak Ridge Reservation was conducted as part of the Oak Ridge National Laboratory Environmental Restoration Program Surveillance and Maintenance activities. This report was prepared to document results of the investigation and subsequent remedial actions. The report details surface gamma radiation levels including gamma anomalies; surface beta radiation levels including beta anomalies; results of analysis of soil, water, and vegetation samples and smear samples collected from paved surfaces; remediation activities conducted as a result of the survey; and recommendations for further corrective measures

  3. White Oak Creek watershed: Melton Valley area Remedial Investigation report, at the Oak Ridge National Laboratory, Oak Ridge, Tennessee: Volume 2, Appendixes A and B

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-11-01

    This document contains Appendixes A ``Source Inventory Information for the Subbasins Evaluated for the White Oak Creek Watershed`` and B ``Human Health Risk Assessment for White Oak Creek / Melton Valley Area`` for the remedial investigation report for the White Oak Creek Watershed and Melton Valley Area. Appendix A identifies the waste types and contaminants for each subbasin in addition to the disposal methods. Appendix B identifies potential human health risks and hazards that may result from contaminants present in the different media within Oak Ridge National Laboratory sites.

  4. White Oak Creek watershed: Melton Valley area Remedial Investigation report, at the Oak Ridge National Laboratory, Oak Ridge, Tennessee: Volume 2, Appendixes A and B

    International Nuclear Information System (INIS)

    1996-11-01

    This document contains Appendixes A ''Source Inventory Information for the Subbasins Evaluated for the White Oak Creek Watershed'' and B ''Human Health Risk Assessment for White Oak Creek / Melton Valley Area'' for the remedial investigation report for the White Oak Creek Watershed and Melton Valley Area. Appendix A identifies the waste types and contaminants for each subbasin in addition to the disposal methods. Appendix B identifies potential human health risks and hazards that may result from contaminants present in the different media within Oak Ridge National Laboratory sites

  5. Basic and Acidic Leaching of Sludge from Melton Valley Storage Tank W-25

    Energy Technology Data Exchange (ETDEWEB)

    Collins, J.L., Egan, B.Z., Beahm, E.C., Chase, C.W., Anderson, K.K.

    1997-10-01

    Bench-scale leaching tests were conducted with samples of tank waste sludge from the Melton Valley Storage Tank (MVST) Facility at Oak Ridge National Laboratory (ORNL) to evaluate separation technology processes for use in concentrating the radionuclides and reducing the volume of waste for final disposal. This paper discusses the hot cell apparatus, the characterization of the sludge, the leaching methodology, and the results obtained from a variety of basic and acidic leaching tests of samples of sludge at ambient temperature. Basic leaching tests were also conducted at 75 and 95 deg C. The major alpha-,gamma., and beta-emitting radionuclides in the centrifuged, wet sludge solids were {sup 137}Cs, {sup 60}Co, {sup 154}Eu, {sup 241}Am, {sup 244}Cm {sup 90}Sr, Pu, U, and Th. The other major metals (in addition to the U and Th) and anions were Na, Ca, Al, K, Mg, NO{sub 3}{sup -},CO{sub 3}{sup 2-}, OH{sup -}, and O{sup 2-} organic carbon content was 3.0 +/- 1.0%. The pH was 13. A surprising result was that about 93% of the {sup 137}Cs in the centrifuged, wet sludge solids was bound in the solids and could not be solubilized by basic leaching at ambient temperature and 75 deg C. However, the solubility of the {sup 137}Cs was enhanced by heating the sludge to 95 deg C. In one of the tests,about 42% of the {sup 137}Cs was removed by leaching with 6.3 M NaOH at 95 deg C.Removing {sup 137}Cs from the W-25 sludge with nitric acid was a slow process. About 13% of the {sup 137}Cs was removed in 16 h with 3.0 M HNO{sub 3}. Only 22% of the {sup 137}Cs was removed in 117 h usi 6.0 M HNO{sub 3}. Successive leaching of sludge solids with 0.5 M, 3.0 M, 3.0 M; and 6.0 M HNO{sub 3} for a total mixing time of 558 h removed 84% of the {sup 137}Cs. The use of caustic leaching prior to HNO{sub 3} leaching, and the use of HF with HNO{sub 3} in acidic leaching, increased the rate of {sup 137}Cs dissolution. Gel formation proved to be one of the biggest problems associated with HNO{sub 3

  6. Basic and Acidic Leaching of Sludge from Melton Valley Storage Tank W-25

    International Nuclear Information System (INIS)

    Collins, J.L.; Egan, B.Z.; Beahm, E.C.; Chase, C.W.; Anderson, K.K.

    1997-10-01

    Bench-scale leaching tests were conducted with samples of tank waste sludge from the Melton Valley Storage Tank (MVST) Facility at Oak Ridge National Laboratory (ORNL) to evaluate separation technology processes for use in concentrating the radionuclides and reducing the volume of waste for final disposal. This paper discusses the hot cell apparatus, the characterization of the sludge, the leaching methodology, and the results obtained from a variety of basic and acidic leaching tests of samples of sludge at ambient temperature. Basic leaching tests were also conducted at 75 and 95 deg C. The major alpha-,gamma., and beta-emitting radionuclides in the centrifuged, wet sludge solids were 137 Cs, 60 Co, 154 Eu, 241 Am, 244 Cm 90 Sr, Pu, U, and Th. The other major metals (in addition to the U and Th) and anions were Na, Ca, Al, K, Mg, NO 3 - ,CO 3 2- , OH - , and O 2- organic carbon content was 3.0 +/- 1.0%. The pH was 13. A surprising result was that about 93% of the 137 Cs in the centrifuged, wet sludge solids was bound in the solids and could not be solubilized by basic leaching at ambient temperature and 75 deg C. However, the solubility of the 137 Cs was enhanced by heating the sludge to 95 deg C. In one of the tests,about 42% of the 137 Cs was removed by leaching with 6.3 M NaOH at 95 deg C.Removing 137 Cs from the W-25 sludge with nitric acid was a slow process. About 13% of the 137 Cs was removed in 16 h with 3.0 M HNO 3 . Only 22% of the 137 Cs was removed in 117 h usi 6.0 M HNO 3 . Successive leaching of sludge solids with 0.5 M, 3.0 M, 3.0 M; and 6.0 M HNO 3 for a total mixing time of 558 h removed 84% of the 137 Cs. The use of caustic leaching prior to HNO 3 leaching, and the use of HF with HNO 3 in acidic leaching, increased the rate of 137 Cs dissolution. Gel formation proved to be one of the biggest problems associated with HNO 3 leaching of the W-25 sludge

  7. Final Verification Success Story Using the Triad Approach at the Oak Ridge National Laboratory's Melton Valley Soils and Sediment Project

    International Nuclear Information System (INIS)

    King, D.A.; Haas, D.A.; Cange, J.B.

    2006-01-01

    The United States Environmental Protection Agency recently published guidance on the Triad approach, which supports the use of smarter, faster, and better technologies and work strategies during environmental site assessment, characterization, and cleanup. The Melton Valley Soils and Sediment Project (Project) at the Oak Ridge National Laboratory embraced this three-pronged approach to characterize contaminants in soil/sediment across the 1000-acre Melton Valley Watershed. Systematic Project Planning is the first of three prongs in the Triad approach. Management initiated Project activities by identifying key technical personnel, included regulators early in the planning phase, researched technologies, and identified available resources necessary to meet Project objectives. Dynamic Work Strategies is the second prong of the Triad approach. Core Team members, including State and Federal regulators, helped develop a Sampling and Analysis Plan that allowed experienced field managers to make real-time, in-the-field decisions and, thus, to adjust to conditions unanticipated during the planning phase. Real-time Measurement Technologies is the third and last prong of the Triad approach. To expedite decision-making, the Project incorporated multiple in-field technologies, including global positioning system equipment integrated with field screening instrumentation, magnetometers for utility clearance, and an on-site gamma spectrometer (spec) for rapid contaminant speciation and quantification. As a result of a relatively complex but highly efficient program, a Project field staff of eight collected approximately 1900 soil samples for on-site gamma spec analysis (twenty percent were also shipped for off-site analyses), 4.7 million gamma radiation measurements, 1000 systematic beta radiation measurements, and 3600 systematic dose rate measurements between July 1, 2004, and October 31, 2005. The site database previously contained results for less than 500 soil samples dating

  8. White Oak Creek Watershed: Melton Valley Area Remedial Investigation Report, Oak Ridge National Laboratory, Oak Ridge, Tennessee: Volume 1 Main Text

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-11-01

    The purpose of this Remedial Investigation (RI) report is to present an analysis of the Melton Valley portion of the White Oak Creek (WOC) watershed, which will enable the US Department of Energy (DOE) to pursue a series of cost-effective remedial actions resulting in site cleanup and stabilization. In this RI existing levels of contamination and radiological exposure are compared to levels acceptable for future industrial and potential recreational use levels at the site. This comparison provides a perspective for the magnitude of remedial actions required to achieve a site condition compatible with relaxed access restrictions over existing conditions. Ecological risk will be assessed to evaluate measures required for ecological receptor protection. For each subbasin, this report will provide site-specific analyses of the physical setting including identification of contaminant source areas, description of contaminant transport pathways, identification of release mechanisms, analysis of contaminant source interactions with groundwater, identification of secondary contaminated media associated with the source and seepage pathways, assessment of potential human health and ecological risks from exposure to contaminants, ranking of each source area within the subwatershed, and outline the conditions that remedial technologies must address to stop present and future contaminant releases, prevent the spread of contamination and achieve the goal of limiting environmental contamination to be consistent with a potential recreational use of the site.

  9. White Oak Creek Watershed: Melton Valley Area Remedial Investigation Report, Oak Ridge National Laboratory, Oak Ridge, Tennessee: Volume 1 Main Text

    International Nuclear Information System (INIS)

    1996-11-01

    The purpose of this Remedial Investigation (RI) report is to present an analysis of the Melton Valley portion of the White Oak Creek (WOC) watershed, which will enable the US Department of Energy (DOE) to pursue a series of cost-effective remedial actions resulting in site cleanup and stabilization. In this RI existing levels of contamination and radiological exposure are compared to levels acceptable for future industrial and potential recreational use levels at the site. This comparison provides a perspective for the magnitude of remedial actions required to achieve a site condition compatible with relaxed access restrictions over existing conditions. Ecological risk will be assessed to evaluate measures required for ecological receptor protection. For each subbasin, this report will provide site-specific analyses of the physical setting including identification of contaminant source areas, description of contaminant transport pathways, identification of release mechanisms, analysis of contaminant source interactions with groundwater, identification of secondary contaminated media associated with the source and seepage pathways, assessment of potential human health and ecological risks from exposure to contaminants, ranking of each source area within the subwatershed, and outline the conditions that remedial technologies must address to stop present and future contaminant releases, prevent the spread of contamination and achieve the goal of limiting environmental contamination to be consistent with a potential recreational use of the site

  10. Remedial investigation report on the Melton Valley Watershed at Oak Ridge National Laboratory, Oak Ridge, Tennessee. Volume 1: Evaluation, interpretation, and data summary

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-05-01

    The Melton Valley watershed presents a multifaceted management and decision-making challenge because of the very heterogeneous conditions that exist with respect to contaminant type, disposal unit age, mode of disposal, release mechanism, and potential risk-producing pathways. The investigation presented here has assembled relevant site data in the geographic context with the intent of enabling program managers and decision-makers to understand site conditions and evaluate the necessity, relative priority, and scope of potential remedial actions.

  11. Remedial investigation report on the Melton Valley Watershed at Oak Ridge National Laboratory, Oak Ridge, Tennessee. Volume 1: Evaluation, interpretation, and data summary

    International Nuclear Information System (INIS)

    1997-05-01

    The Melton Valley watershed presents a multifaceted management and decision-making challenge because of the very heterogeneous conditions that exist with respect to contaminant type, disposal unit age, mode of disposal, release mechanism, and potential risk-producing pathways. The investigation presented here has assembled relevant site data in the geographic context with the intent of enabling program managers and decision-makers to understand site conditions and evaluate the necessity, relative priority, and scope of potential remedial actions

  12. White Oak Creek Watershed: Melton Valley Area Remedial Investigation Report, Oak Ridge National Laboratory, Oak Ridge, Tennessee: Volume 3 Appendix C

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-11-01

    This report provides details on the baseline ecological risk assessment conducted in support of the Remedial Investigation (RI) Report for the Melton Valley areas of the White Oak Creek watershed (WOCW). The RI presents an analysis meant to enable the US Department of Energy (DOE) to pursue a series of remedial actions resulting in site cleanup and stabilization. The ecological risk assessment builds off of the WOCW screening ecological risk assessment. All information available for contaminated sites under the jurisdiction of the US Department of Energy`s Comprehensive Environmental Response, Compensation, and Liability Act Federal Facilities Agreement within the White Oak Creek (WOC) RI area has been used to identify areas of potential concern with respect to the presence of contamination posing a potential risk to ecological receptors within the Melton Valley area of the White Oak Creek watershed. The risk assessment report evaluates the potential risks to receptors within each subbasin of the watershed as well as at a watershed-wide scale. The WOC system has been exposed to contaminant releases from Oak Ridge National Laboratory and associated operations since 1943 and continues to receive contaminants from adjacent waste area groupings.

  13. White Oak Creek Watershed: Melton Valley Area Remedial Investigation Report, Oak Ridge National Laboratory, Oak Ridge, Tennessee: Volume 3 Appendix C

    International Nuclear Information System (INIS)

    1996-11-01

    This report provides details on the baseline ecological risk assessment conducted in support of the Remedial Investigation (RI) Report for the Melton Valley areas of the White Oak Creek watershed (WOCW). The RI presents an analysis meant to enable the US Department of Energy (DOE) to pursue a series of remedial actions resulting in site cleanup and stabilization. The ecological risk assessment builds off of the WOCW screening ecological risk assessment. All information available for contaminated sites under the jurisdiction of the US Department of Energy's Comprehensive Environmental Response, Compensation, and Liability Act Federal Facilities Agreement within the White Oak Creek (WOC) RI area has been used to identify areas of potential concern with respect to the presence of contamination posing a potential risk to ecological receptors within the Melton Valley area of the White Oak Creek watershed. The risk assessment report evaluates the potential risks to receptors within each subbasin of the watershed as well as at a watershed-wide scale. The WOC system has been exposed to contaminant releases from Oak Ridge National Laboratory and associated operations since 1943 and continues to receive contaminants from adjacent waste area groupings

  14. Hydrogeochemical assessment of groundwater in Kashmir Valley ...

    Indian Academy of Sciences (India)

    Groundwater samples ( = 163) were collected across Kashmir Valley in 2010 to assess the hydrogeochemistry of the groundwater in shallow and deep aquifers and its suitability for domestic, agriculture, horticulture, and livestock purposes. The groundwater is generally alkaline in nature. The electrical conductivity (EC) ...

  15. Hydrogeochemical assessment of groundwater in Kashmir Valley ...

    Indian Academy of Sciences (India)

    Groundwater samples (n = 163) were collected across Kashmir Valley in 2010 to assess the hydrogeo- chemistry of the groundwater in shallow and deep aquifers and its suitability for domestic, agriculture, horticulture, and livestock purposes. The groundwater is generally alkaline in nature. The electrical conductivity (EC) ...

  16. Groundwater links between Kenyan Rift Valley lakes

    OpenAIRE

    Becht, Robert; Mwango, Fred; Muno, Fred Amstrong

    2006-01-01

    The series of lakes in the bottom of the Kenyan Rift valley are fed by rivers and springs. Based on the water balance, the relative positions determining the regional groundwater flow systems and the analysis of natural isotopes it can be shown that groundwater flows from lake Naivasha to lake Magadi, Elementeita, Nakuru and Bogoria.

  17. Groundwater quality in Coachella Valley, California

    Science.gov (United States)

    Dawson, Barbara J. Milby; Belitz, Kenneth

    2012-01-01

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. Coachella Valley is one of the study areas being evaluated. The Coachella study area is approximately 820 square miles (2,124 square kilometers) and includes the Coachella Valley groundwater basin (California Department of Water Resources, 2003). Coachella Valley has an arid climate, with average annual rainfall of about 6 inches (15 centimeters). The runoff from the surrounding mountains drains to rivers that flow east and south out of the study area to the Salton Sea. Land use in the study area is approximately 67 percent (%) natural, 21% agricultural, and 12% urban. The primary natural land cover is shrubland. The largest urban areas are the cities of Indio and Palm Springs (2010 populations of 76,000 and 44,000, respectively). Groundwater in this basin is used for public and domestic water supply and for irrigation. The main water-bearing units are gravel, sand, silt, and clay derived from surrounding mountains. The primary aquifers in Coachella Valley are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database. Public-supply wells in Coachella Valley are completed to depths between 490 and 900 feet (149 to 274 meters), consist of solid casing from the land surface to a depth of 260 to 510 feet (79 to 155 meters), and are screened or perforated below the solid casing. Recharge to the groundwater system is primarily runoff from the surrounding mountains, and by direct infiltration of irrigation. The primary sources of discharge are pumping wells, evapotranspiration, and underflow to

  18. Groundwater quality in the Antelope Valley, California

    Science.gov (United States)

    Dawson, Barbara J. Milby; Belitz, Kenneth

    2012-01-01

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. Antelope Valley is one of the study areas being evaluated. The Antelope study area is approximately 1,600 square miles (4,144 square kilometers) and includes the Antelope Valley groundwater basin (California Department of Water Resources, 2003). Antelope Valley has an arid climate and is part of the Mojave Desert. Average annual rainfall is about 6 inches (15 centimeters). The study area has internal drainage, with runoff from the surrounding mountains draining towards dry lakebeds in the lower parts of the valley. Land use in the study area is approximately 68 percent (%) natural (mostly shrubland and grassland), 24% agricultural, and 8% urban. The primary crops are pasture and hay. The largest urban areas are the cities of Palmdale and Lancaster (2010 populations of 152,000 and 156,000, respectively). Groundwater in this basin is used for public and domestic water supply and for irrigation. The main water-bearing units are gravel, sand, silt, and clay derived from surrounding mountains. The primary aquifers in Antelope Valley are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database. Public-supply wells in Antelope Valley are completed to depths between 360 and 700 feet (110 to 213 meters), consist of solid casing from the land surface to a depth of 180 to 350 feet (55 to 107 meters), and are screened or perforated below the solid casing. Recharge to the groundwater system is primarily runoff from the surrounding mountains, and by direct infiltration of irrigation and sewer and septic

  19. Groundwater quality in the Owens Valley, California

    Science.gov (United States)

    Dawson, Barbara J. Milby; Belitz, Kenneth

    2012-01-01

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. Owens Valley is one of the study areas being evaluated. The Owens study area is approximately 1,030 square miles (2,668 square kilometers) and includes the Owens Valley groundwater basin (California Department of Water Resources, 2003). Owens Valley has a semiarid to arid climate, with average annual rainfall of about 6 inches (15 centimeters). The study area has internal drainage, with runoff primarily from the Sierra Nevada draining east to the Owens River, which flows south to Owens Lake dry lakebed at the southern end of the valley. Beginning in the early 1900s, the City of Los Angeles began diverting the flow of the Owens River to the Los Angeles Aqueduct, resulting in the evaporation of Owens Lake and the formation of the current Owens Lake dry lakebed. Land use in the study area is approximately 94 percent (%) natural, 5% agricultural, and 1% urban. The primary natural land cover is shrubland. The largest urban area is the city of Bishop (2010 population of 4,000). Groundwater in this basin is used for public and domestic water supply and for irrigation. The main water-bearing units are gravel, sand, silt, and clay derived from surrounding mountains. Recharge to the groundwater system is primarily runoff from the Sierra Nevada, and by direct infiltration of irrigation. The primary sources of discharge are pumping wells, evapotranspiration, and underflow to the Owens Lake dry lakebed. The primary aquifers in Owens Valley are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database

  20. Groundwater quality in the western San Joaquin Valley, California

    Science.gov (United States)

    Fram, Miranda S.

    2017-06-09

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. The Western San Joaquin Valley is one of the study units being evaluated. 

  1. Groundwater recharge on east side soils of the Salinas Valley

    Science.gov (United States)

    After four years of drought, groundwater levels in the Salinas Valley are at historically low levels which threaten to adversely affect farming in the Salinas Valley. Given the prospect of a strong El Niño this coming winter, it seems prudent to plan to capture as much of the rainfall as possible to...

  2. Groundwater availability of the Central Valley Aquifer, California

    Science.gov (United States)

    Faunt, Claudia C.

    2009-01-01

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

  3. Hydrogeochemical assessment of groundwater in Kashmir Valley ...

    Indian Academy of Sciences (India)

    local surface topography which not only modifies the hydrogeochemical facies but also controls their distribution. The groundwater ... sodium carbonate, and PI suggested that groundwater is good for drinking, livestock, and irrigation purposes. 1. Introduction ... Hydrogeochemical study is a useful tool in under- standing and ...

  4. Groundwater quality in the Indian Wells Valley, California

    Science.gov (United States)

    Dawson, Barbara J. Milby; Belitz, Kenneth

    2012-01-01

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. Indian Wells Valley is one of the study areas being evaluated. The Indian Wells study area is approximately 600 square miles (1,554 square kilometers) and includes the Indian Wells Valley groundwater basin (California Department of Water Resources, 2003). Indian Wells Valley has an arid climate and is part of the Mojave Desert. Average annual rainfall is about 6 inches (15 centimeters). The study area has internal drainage, with runoff from the surrounding mountains draining towards dry lake beds in the lower parts of the valley. Land use in the study area is approximately 97.0 percent (%) natural, 0.4% agricultural, and 2.6% urban. The primary natural land cover is shrubland. The largest urban area is the city of Ridgecrest (2010 population of 28,000). Groundwater in this basin is used for public and domestic water supply and for irrigation. The main water-bearing units are gravel, sand, silt, and clay derived from the Sierra Nevada to the west and from the other surrounding mountains. Recharge to the groundwater system is primarily runoff from the Sierra Nevada and to the west and from the other surrounding mountains. Recharge to the groundwater system is primarily runoff from the Sierra Nevada and direct infiltration from irrigation and septic systems. The primary sources of discharge are pumping wells and evapotranspiration near the dry lakebeds. The primary aquifers in the Indian Wells study area are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database. Public-supply wells in

  5. Groundwater-flow and land-subsidence model of Antelope Valley, California

    Science.gov (United States)

    Siade, Adam J.; Nishikawa, Tracy; Rewis, Diane L.; Martin, Peter; Phillips, Steven P.

    2014-01-01

    Antelope Valley, California, is a topographically closed basin in the western part of the Mojave Desert, about 50 miles northeast of Los Angeles. The Antelope Valley groundwater basin is about 940 square miles and is separated from the northern part of Antelope Valley by faults and low-lying hills. Prior to 1972, groundwater provided more than 90 percent of the total water supply in the valley; since 1972, it has provided between 50 and 90 percent. Most groundwater pumping in the valley occurs in the Antelope Valley groundwater basin, which includes the rapidly growing cities of Lancaster and Palmdale. Groundwater-level declines of more than 270 feet in some parts of the groundwater basin have resulted in an increase in pumping lifts, reduced well efficiency, and land subsidence of more than 6 feet in some areas. Future urban growth and limits on the supply of imported water may increase reliance on groundwater.

  6. Hydrogeochemical investigations of groundwater in Ziarat valley, Baluchistan

    International Nuclear Information System (INIS)

    Akram, W.; Ahmad, M.; Rafiq, M.

    2010-03-01

    Present study was undertaken in Ziarat Valley, Baluchistan to investigate recent trends of groundwater chemistry (geochemical facies, geochemical evolution) and assess the groundwater quality for drinking and irrigation purposes. For this purpose samples of groundwater (open wells, tube wells, karezes, springs) were periodically collected from different locations and analyzed for dissolved chemical constituents such as sodium, potassium, magnesium, calcium, carbonate, bicarbonate, chloride and sulphate. The data indicated that concentrations of sodium, potassium, calcium and magnesium vary from 5 to 113,0.3 to 3,18 to 62 and 27 to 85 mg/l respectively. Values of anions i. e. bicarbonate, chloride and sulphate lie in the range of 184 to 418, 14 to 77 and 8 to 318 mg/l respectively. Hydrogeochemical facies revealed that groundwater in the study area belongs to Mg-HCO/sub 3/ type at 72% surveyed locations. Dissolution and calcite precipitation were found to be the main processes controlling the groundwater chemistry. Chemical quality was assessed for drinking use by comparing with WHO, Indian and proposed national standards, and for irrigation use using empirical indices such as SAR and RSC. The results show that groundwater is quite suitable for irrigation and drinking purposes. (author)

  7. Preliminary hydrogeologic assessment near the boundary of the Antelope Valley and El Mirage Valley groundwater basins, California

    Science.gov (United States)

    Stamos, Christina L.; Christensen, Allen H.; Langenheim, Victoria

    2017-07-19

    The increasing demands on groundwater for water supply in desert areas in California and the western United States have resulted in the need to better understand groundwater sources, availability, and sustainability. This is true for a 650-square-mile area that encompasses the Antelope Valley, El Mirage Valley, and Upper Mojave River Valley groundwater basins, about 50 miles northeast of Los Angeles, California, in the western part of the Mojave Desert. These basins have been adjudicated to ensure that groundwater rights are allocated according to legal judgments. In an effort to assess if the boundary between the Antelope Valley and El Mirage Valley groundwater basins could be better defined, the U.S. Geological Survey began a cooperative study in 2014 with the Mojave Water Agency to better understand the hydrogeology in the area and investigate potential controls on groundwater flow and availability, including basement topography.Recharge is sporadic and primarily from small ephemeral washes and streams that originate in the San Gabriel Mountains to the south; estimates range from about 400 to 1,940 acre-feet per year. Lateral underflow from adjacent basins has been considered minor in previous studies; underflow from the Antelope Valley to the El Mirage Valley groundwater basin has been estimated to be between 100 and 1,900 acre-feet per year. Groundwater discharge is primarily from pumping, mostly by municipal supply wells. Between October 2013 and September 2014, the municipal pumpage in the Antelope Valley and El Mirage Valley groundwater basins was reported to be about 800 and 2,080 acre-feet, respectively.This study was motivated by the results from a previously completed regional gravity study, which suggested a northeast-trending subsurface basement ridge and saddle approximately 3.5 miles west of the boundary between the Antelope Valley and El Mirage Valley groundwater basins that might influence groundwater flow. To better define potential basement

  8. Groundwater quality in the Monterey Bay and Salinas Valley groundwater basins, California

    Science.gov (United States)

    Kulongoski, Justin T.; Belitz, Kenneth

    2011-01-01

    The Monterey-Salinas study unit is nearly 1,000 square miles and consists of the Santa Cruz Purisima Formation Highlands, Felton Area, Scotts Valley, Soquel Valley, West Santa Cruz Terrace, Salinas Valley, Pajaro Valley, and Carmel Valley groundwater basins (California Department of Water Resources, 2003; Kulongski and Belitz, 2011). These basins were grouped into four study areas based primarily on geography. Groundwater basins in the north were grouped into the Santa Cruz study area, and those to the south were grouped into the Monterey Bay, the Salinas Valley, and the Paso Robles study areas (Kulongoski and others, 2007). The study unit has warm, dry summers and cool, moist winters. Average annual rainfall ranges from 31 inches in Santa Cruz in the north to 13 inches in Paso Robles in the south. The study areas are drained by several rivers and their principal tributaries: the Salinas, Pajaro, and Carmel Rivers, and San Lorenzo Creek. The Salinas Valley is a large intermontane valley that extends southeastward from Monterey Bay to Paso Robles. It has been filled, up to a thickness of 2,000 feet, with Tertiary and Quaternary marine and terrestrial sediments that overlie granitic basement. The Miocene-age Monterey Formation and Pliocene- to Pleistocene-age Paso Robles Formation, and Pleistocene to Holocene-age alluvium contain freshwater used for supply. The primary aquifers in the study unit are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database. Public-supply wells are typically drilled to depths of 200 to 650 feet, consist of solid casing from the land surface to depths of about 175 to 500 feet, and are perforated below the solid casing. Water quality in the primary aquifers may differ from that in the shallower and deeper parts of the aquifer system. Groundwater movement is generally from the southern part of the Salinas Valley north towards the Monterey Bay

  9. Appraisal of groundwater resources of Ziarat valley using isotopic techniques

    International Nuclear Information System (INIS)

    Ahmad, M.; Akram, W.; Tasneem, M.A.; Rafique, M.

    2009-07-01

    Study of water resources of Ziarat Valley was carried out to investigate groundwater recharge mechanism and effectiveness of delay action dams. Samples of precipitation (rain, snow), dam reservoirs and groundwater (dug wells, tube wells, karezes, springs) were periodically collected from different locations and analyzed for environmental isotopes (/sup 2/H, /sup 3/H, /sup 18/O, /sup 34/S). The data indicate that rainfall and snow samples show wide ranges of delta /sup 2/H and delta /sup 18/O. However, the mean values for these isotopes are -6.4% and -37% respectively. Mean tritium value of rain is 9TU. Delta /sup 2/H and delta /sup 18/O values of dam reservoirs range from -6.7 to +4.9% and -42 to +30% respectively. Average isotopic indices of all the karezes are close to each other. Mean delta /sup 18/O and delta /sup 2/H values of Sandaman Tangi, Faran Tangi and Quaid springs vary from -6.3 to -6% and -40 to -31%. Tritium concentration of Sandaman Tangi and Faran Tangi springs (7 TU) is less than Quaid spring (11TU). Ranges of mean delta /sup 18/O and delta /sup 2/H values of all the groundwater samples (wells, karezes, springs) are -6.6 to -2.2% and -40 to -16% respectively. Delta /sup 34/S values of dissolved sulphates in groundwater vary from -8.5 to -0.8%. In /sup 18/O vs. /sup 2/H plot, most of the groundwater samples lie close to LMWL indicating the meteoric origin. Reservoir water in Pechi Dam shows highly enriched isotopic values in summer due to evaporation. Such enriched values are not depicted by the groundwater in the wells and karezes downstream of the dam. This implies that there is no significant recharge from this dam. Similar is the case of Mana Dam. Vouch Ghouski Dam has some contribution towards groundwater recharge while Warchoom Dam is much effective and makes significant contribution. Results of tritium dating suggest that residence time of groundwater is quite short (only few years). (author)

  10. Lateral groundwater inflows into alluvial aquifers of main alpine valleys

    Science.gov (United States)

    Burger, Ulrich

    2015-04-01

    In alpine regions the topography is mainly characterised by deep incised valleys, mountain slopes and ridges. Usually the main valleys contain aquifers in alluvial soft rock. Lateral these aquifers are confined by mountainous hard rock slopes covered by heterogeneous sediments with different thickness. The slopes can be incised by lateral valleys. Numerical models for the main alluvial aquifers ask for lateral hydrogeological boundaries. Usually no flow boundaries or Constant head Boundaries are used, even if the lateral inflows to the main aquifers are rarely known. In this example a data set for a detailed investigated and monitored area is studied to give an answer on the location and the quantification of these lateral subsurface inflows. The study area is a typical main alpine valley with a thick alluvial aquifer (appr. 120m thick), lateral confined by granite, covered at the base of the steep slopes by quaternary sediments (Burger at al. 2012). The study consists of several steps 1.) Analytical calculation of the inflows on the base of investigated and monitored 2d profiles along fault zones (Perello et al 2013) which pinch out in the main valley 2.) Analytical models along typical W-dipping slopes with monitored slope springs 3.) Evaluating temperature and electrical conductivity profiles measured in approx. 30 groundwater wells in the alluvial aquifers and along the slopes to locate main lateral subsurface inflows 4.) Output of a regional model used for the hydrogeological back analyses of the excavation of a tunnel (Baietto et al. 2014) 5.) Output of a local numerical model calibrated with a monitoring dataset and results of a pumping test of big scale (450l/s for 10days) Results of these analyses are shown to locate and quantify the lateral groundwater inflows in the main alluvial aquifer. References Baietto A., Burger U., Perello P. (2014): Hydrogeological modelling applications in tunnel excavations: examples from tunnel excavations in granitic rocks

  11. The effects of drainage on groundwater quality and plant species distribution in stream valley meadows

    NARCIS (Netherlands)

    Grootjans, A.P.; Diggelen, R. van; Wassen, M.J.; Wiersinga, W.A.

    1988-01-01

    Conditions in fen meadows in Dutch stream valleys are influenced by both deep (Ca2+-rich) and shallow (Ca2+-poor) groundwater flows. The distribution patterns of phreatophytic (groundwater-influenced) plant species showed distinct relationships with the distribution of different groundwater types.

  12. A Comparison of Groundwater Storage Using GRACE Data, Groundwater Levels, and a Hydrological Model in Californias Central Valley

    Science.gov (United States)

    Kuss, Amber; Brandt, William; Randall, Joshua; Floyd, Bridget; Bourai, Abdelwahab; Newcomer, Michelle; Skiles, Joseph; Schmidt, Cindy

    2011-01-01

    The Gravity Recovery and Climate Experiment (GRACE) measures changes in total water storage (TWS) remotely, and may provide additional insight to the use of well-based data in California's agriculturally productive Central Valley region. Under current California law, well owners are not required to report groundwater extraction rates, making estimation of total groundwater extraction difficult. As a result, other groundwater change detection techniques may prove useful. From October 2002 to September 2009, GRACE was used to map changes in TWS for the three hydrological regions (the Sacramento River Basin, the San Joaquin River Basin, and the Tulare Lake Basin) encompassing the Central Valley aquifer. Net groundwater storage changes were calculated from the changes in TWS for each of the three hydrological regions and by incorporating estimates for additional components of the hydrological budget including precipitation, evapotranspiration, soil moisture, snow pack, and surface water storage. The calculated changes in groundwater storage were then compared to simulated values from the California Department of Water Resource's Central Valley Groundwater- Surface Water Simulation Model (C2VSIM) and their Water Data Library (WDL) Geographic Information System (GIS) change in storage tool. The results from the three methods were compared. Downscaling GRACE data into the 21 smaller Central Valley sub-regions included in C2VSIM was also evaluated. This work has the potential to improve California's groundwater resource management and use of existing hydrological models for the Central Valley.

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

    Science.gov (United States)

    Patel, Tanya; Hindshaw, Ruth; Singer, Michael

    2015-04-01

    Water is a vital resource in any agricultural watershed, yet in the arid western United States farming practices threaten the quality and availability of groundwater. This is a pressing concern in the San Luis Valley, southern Colorado, where agriculture comprises 30% of the local economy, and employs over half the valley population. Although 54 % of the water used for irrigation is surface water, farmers do not usually apply this water directly to their fields. Instead, the water is often diverted into pits which recharge the aquifer, and the water is subsequently pumped during the following irrigation season. The Rio Grande Water Conservation District recognises that recharge to the unconfined aquifer has been outpaced by commercial irrigation for at least four decades, resulting in a decline in groundwater levels. Recycled irrigation water, and leakage from unlined canals now represent the greatest recharge contribution to the unconfined aquifer in this region. This makes the shallow groundwater particularly susceptible to agricultural contamination. The purpose of this study is to assess groundwater contamination in the unconfined and upper confined aquifers of the San Luis Valley, which are the most susceptible to contamination due to their close proximity to the surface. Although concentrations of potentially harmful contaminants from agricultural runoff are regularly monitored, the large spatial and temporal fluctuations in values make it difficult to determine long-term trends. We have analysed δ18O, δ2H and major-ion chemistry of 57 groundwater, stream and precipitation samples, collected in June 2014, and interpreted them alongside regional stream flow data and groundwater levels. This will allow us to study the seasonality and locality of groundwater recharge to provide greater insight into the watershed's potential for pollution. A groundwater vulnerability assessment was performed using the model DRASTIC (Depth to water, Recharge, Aquifer media, Soil

  14. Groundwater quality in the Bear Valley and Lake Arrowhead Watershed, California

    Science.gov (United States)

    Mathany, Timothy; Burton, Carmen; Fram, Miranda S.

    2017-06-20

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. The Bear Valley and Lake Arrowhead Watershed study areas in southern California compose one of the study units being evaluated.

  15. Assessment of groundwater vulnerability and risk to pollution in Kathmandu Valley, Nepal.

    Science.gov (United States)

    Shrestha, Sangam; Semkuyu, Dickson John; Pandey, Vishnu P

    2016-06-15

    Groundwater vulnerability and risk assessment is a useful tool for groundwater pollution prevention and control. In this study, GIS based DRASTIC model have been used to assess intrinsic aquifer vulnerability to pollution whereas Groundwater Risk Assessment Model (GRAM) was used to assess the risk to groundwater pollution in the groundwater basin of Kathmandu Valley. Seven hydrogeological factors were used in DRASTIC model to produce DRASTIC Index (DI) map which represent intrinsic groundwater vulnerability to pollution of the area. The seven hydrogeological factors used were depth to water, net recharge, aquifer media, soil media, topography, impact of vadose zone, and hydraulic conductivity of aquifer. GIS based GRAM was used to produce likelihood of release of hazards, likelihood of detection of hazards, consequence of hazards and residual risk of groundwater contamination in terms of nitrate in the groundwater basin. It was found that more than 50% of the groundwater basin area in the valley is susceptible to groundwater pollution and these areas are mostly in Northern groundwater district Low and very low vulnerable areas account for only 13% and are located in Central and Southern groundwater districts. However after taking into account the barriers to groundwater pollution and likelihood of hazards release and detection, it was observed that most areas i.e. about 87% of the groundwater basin are at moderate residual risk to groundwater pollution. The resultant groundwater vulnerability and risk map provides a basis for policy makers and planner's ability to use information effectively for decision making at protecting the groundwater from pollutants. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    International Nuclear Information System (INIS)

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

    1995-01-01

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

  17. Budgets and chemical characterization of groundwater for the Diamond Valley flow system, central Nevada, 2011–12

    Science.gov (United States)

    Berger, David L.; Mayers, C. Justin; Garcia, C. Amanda; Buto, Susan G.; Huntington, Jena M.

    2016-07-29

    The Diamond Valley flow system consists of six hydraulically connected hydrographic areas in central Nevada. The general down-gradient order of the areas are southern and northern Monitor Valleys, Antelope Valley, Kobeh Valley, Stevens Basin, and Diamond Valley. Groundwater flow in the Diamond Valley flow system terminates at a large playa in the northern part of Diamond Valley. Concerns relating to continued water-resources development of the flow system resulted in a phased hydrologic investigation that began in 2005 by the U.S. Geological Survey in cooperation with Eureka County. This report presents the culmination of the phased investigation to increase understanding of the groundwater resources of the basin-fill aquifers in the Diamond Valley flow system through evaluations of groundwater chemistry and budgets. Groundwater chemistry was characterized using major ions and stable isotopes from groundwater and precipitation samples. Groundwater budgets accounted for all inflows, outflows, and changes in storage, and were developed for pre-development (pre-1950) and recent (average annual 2011–12) conditions. Major budget components include groundwater discharge by evapotranspiration and groundwater withdrawals; groundwater recharge by precipitation, and interbasin flow; and storage change.

  18. Field Scale Groundwater Nitrate Loading Model for the Central Valley, California, 1945-Current

    Science.gov (United States)

    Harter, T.; Dzurella, K.; Bell, A.; Kourakos, G.

    2015-12-01

    Anthropogenic groundwater nitrate contamination in the Central Valley aquifer system, California, is widespread, with over 40% of domestic wells in some counties exceeding drinking water standards. Sources of groundwater nitrate include leaky municipal wastewater systems, municipal wastewater recharge, onsite wastewater treatment (septic) systems, atmospheric nitrogen deposition, animal farming, application of organic waste materials (sludge, biosolids, animal manure) to agricultural lands, and synthetic fertilizer. At the site or field scale, nitrogen inputs to the landscape are balanced by plant nitrogen uptake and harvest, atmospheric nitrogen losses, surface runoff of nitrogen, soil nitrogen storage changes, and leaching to groundwater. Irrigated agriculture is a dominant player in the Central Valley nitrogen cycle: The largest nitrogen fluxes are synthetic fertilizer and animal manure applications to cropland, crop nitrogen uptake, and groundwater nitrogen losses. We construct a historic field/parcel scale groundwater nitrogen loading model distinguishing urban and residential areas, individual animal farming areas, leaky wastewater lagoons, and approximately 50 different categories of agricultural crops. For non-agricultural landuses, groundwater nitrate loading is based on reported leaching values, animal population, and human population. For cropland, groundwater nitrate loading is computed from mass balance, taking into account diverse and historically changing management practices between different crops. Groundwater nitrate loading is estimated for 1945 to current. Significant increases in groundwater nitrate loading are associated with the expansion of synthetic fertilizer use in the 1950s to 1970s. Nitrate loading from synthetic fertilizer use has stagnated over the past 20 years due to improvements in nutrient use efficiency. However, an unbroken 60 year exponential increase in dairy production until the late 2000s has significantly impacted the

  19. A Guide for Using the Transient Ground-Water Flow Model of the Death Valley Regional Ground-Water Flow System, Nevada and California

    Energy Technology Data Exchange (ETDEWEB)

    Joan B. Blainey; Claudia C. Faunt, and Mary C. Hill

    2006-05-16

    This report is a guide for executing numerical simulations with the transient ground-water flow model of the Death Valley regional ground-water flow system, Nevada and California using the U.S. Geological Survey modular finite-difference ground-water flow model, MODFLOW-2000. Model inputs, including observations of hydraulic head, discharge, and boundary flows, are summarized. Modification of the DVRFS transient ground-water model is discussed for two common uses of the Death Valley regional ground-water flow system model: predictive pumping scenarios that extend beyond the end of the model simulation period (1998), and model simulations with only steady-state conditions.

  20. Vulnerability of Groundwater Recharge to Climate Change in an Alpine Basin (Martis Valley, California)

    Science.gov (United States)

    Visser, A.; Segal, D.; Urióstegui, S. H.; Singleton, M. J.; Moran, J. E.; Esser, B. K.

    2013-12-01

    Martis Valley's groundwater basin is experiencing increasing water demand and changes in the amount and timing of snowmelt due to climate change. Groundwater is the exclusive water supply for the town of Truckee and its surrounding ski resorts and golf courses. The objective of this study was to examine seasonal variability in the aquifer recharge by analyzing supply wells for: 1) tritium and helium isotopes to determine groundwater sources and age, 2) dissolved noble gases to determine recharge temperatures and excess air concentrations and 3) stable isotopes to determine groundwater sources. Recharge temperatures were found to be similar to mean annual air temperatures at lower elevations, suggesting that most recharge is occurring at lower elevations after equilibrating in the vadose zone. Low levels of excess air found in groundwater confirm that most recharge is occurring in the valley alluvium rather than the mountain block. The mean integrated groundwater flow depth was estimated for each well from the temperature difference between recharge and discharge and the geothermal gradient. Groundwater samples contained large amounts of excess terrigenic helium, from both mantle and radiogenic sources. Terrigenic helium and tritium concentrations were used to reconstruct the mixing between the younger and older groundwater sources. Mantle helium originating from the Polaris Fault was used to trace groundwater flow directions. Higher seasonal variability was found in wells with younger groundwater and shallower flow depths, suggesting that changes in the timing and amount of recharge under warmer climate conditions will rather quickly impact at least a portion of the aquifer system in Martis Valley. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  1. ANALYSIS OF SPATIAL CHANGES IN GROUNDWATER RETENTION FOR THE ODER VALLEY IN THE MALCZYCE REGION

    Directory of Open Access Journals (Sweden)

    Edyta Nowicka

    2015-10-01

    Full Text Available The paper presents the analysis of spatial changes of groundwater retention for a part of the Oder valley situated below the barrage in Brzeg Dolny. For the analysis of selected monthly average elevations of the groundwater table of the selected measuring points (32 piezometers located in the area described, and 7 gauges on the Oder river, Średzka Woda, Jeziorka and Nowy Rów. The change of groundwater retention is presented in spatial terms for vegetation periods of years: 2010, 2011 and 2012. The database was made interpolating the groundwater table elevation for the area in question. On this basis, differences between ordinates the groundwater table were calculated. The next step was to obtain the spatial distribution of groundwater retention states and its analysis. The results show significant changes in the states of groundwater retention on the selected portion of the valley in the individual growing seasons. According to formation of changes in status of groundwater retention relative to the distance from the Odra river was analysed.

  2. The transport of contaminants during storms in the White Oak Creek and Melton Branch Watersheds

    International Nuclear Information System (INIS)

    Solomon, D.K.; Marsh, J.D.; Wickliff, D.S.; Larsen, I.L.; Clapp, R.B.

    1989-03-01

    This report documents are transport of contaminants from SWSA 5 along two principle pathways: the saturated groundwater system and the intermittently saturated stormflow system. The results of a baseflow sampling effort and a dye tracer study, indicated that much of the transport through the saturated groundwater system occurs along discrete geologic features. These features appear to be related to the contact between the Maryville and Nolichucky members of the Conasauga shale. Three discrete sources of tritium to Melton Branch Stream (MBS) were identified and traced to SWSA 5 by measuring soil moisture and evapotranspiration along transects between MBS and SWSA 5

  3. Groundwater-Mining-Induced Subsidence and Earth Fissures in Cedar Valley, Southwestern Utah

    Science.gov (United States)

    Knudsen, T. R.; Inkenbrandt, P.; Lund, W. R.; Lowe, M.; Bowman, S. D.

    2014-12-01

    Groundwater pumping in excess of recharge (groundwater mining) has lowered the potentiometric surface in Cedar Valley, southwestern Utah, by as much as 114 feet since 1939. Lowering the potentiometric surface (head decline) has caused permanent compaction of fine-grained sediments of the Cedar Valley aquifer. Recently acquired interferometric synthetic aperture radar (InSAR) imagery shows that land subsidence is occurring over an ~100 square-mile area, including two pronounced subsidence bowls in the northeastern (Enoch graben) and southwestern (Quichapa Lake area) parts of the valley. A lack of accurate historical benchmark elevation data over much of the valley prevents detailed long-term quantification of subsidence. In response to the land subsidence, earth fissures have formed along the margins of the Enoch graben and north and west of Quichapa Lake. Our initial inventory of Cedar Valley fissures, which relied on aerial-photography analysis, identified 3.9 miles of fissures in 2009. With newly acquired light detection and ranging (LiDAR) coverage in 2011, we more than doubled the total length of mapped fissures to 8.3 miles. Fissures on the west side of the Enoch graben exhibit ongoing vertical surface displacement with rates as high as 1.7 inches/year. The largest Enoch-graben-west fissure has displaced street surfaces, curb and gutter, and sidewalks, and has reversed the flow direction of a sewer line in a partially developed subdivision. Several Cedar Valley fissures are closely associated with, and in some places coincident with, mapped Quaternary faults. While the majority of Cedar Valley fissures are mapped in agricultural areas, continued groundwater mining and resultant subsidence will likely cause existing fissures to lengthen and new fissures to form that may eventually impact other developed areas of the valley.

  4. Geochemical and Isotopic Interpretations of Groundwater Flow in the Oasis Valley Flow System, Southern Nevada

    Energy Technology Data Exchange (ETDEWEB)

    J.M. Thomas; F.C. Benedict, Jr.; T.P. Rose; R.L. Hershey; J.B. Paces; Z.E. Peterman; I.M. Farnham; K.H. Johannesson; A.K. Singh; K.J. Stetzenbach; G.B. Hudson; J.M. Kenneally; G.F. Eaton; D.K. Smith

    2003-01-08

    This report summarizes the findings of a geochemical investigation of the Pahute Mesa-Oasis Valley groundwater flow system in southwestern Nevada. It is intended to provide geochemical data and interpretations in support of flow and contaminant transport modeling for the Western and Central Pahute Mesa Corrective Action Units.

  5. Geochemical and Isotopic Interpretations of Groundwater Flow in the Oasis Valley Flow System, Southern Nevada

    International Nuclear Information System (INIS)

    Thomas, J.M.; Benedict, F.C. Jr.; Rose, T.P.; Hershey, R.L.; Paces, J.B.; Peterman, Z.E.; Farnham, I.M.; Johannesson, K.H.; Singh, A.K.; Stetzenbach, K.J.; Hudson, G.B.; Kenneally, J.M.; Eaton, G.F.; Smith, D.K.

    2003-01-01

    This report summarizes the findings of a geochemical investigation of the Pahute Mesa-Oasis Valley groundwater flow system in southwestern Nevada. It is intended to provide geochemical data and interpretations in support of flow and contaminant transport modeling for the Western and Central Pahute Mesa Corrective Action Units

  6. Evaluation of index-overlay methods for groundwater vulnerability and risk assessment in Kathmandu Valley, Nepal.

    Science.gov (United States)

    Shrestha, Sangam; Kafle, Ranjana; Pandey, Vishnu Prasad

    2017-01-01

    This study aimed at evaluating three index-overlay methods of vulnerability assessment (i.e., DRASTIC, GOD, and SI) for estimating risk to pollution of shallow groundwater aquifer in the Kathmandu Valley, Nepal. The Groundwater Risk Assessment Model (GRAM) model was used to compute the risk to groundwater pollution. Results showed that DRASTIC and SI methods are comparable for vulnerability assessment as both methods delineate around 80% of the groundwater basin area under high vulnerable zone. From the perspective of risk to pollution results, DRASTIC and GOD methods are comparable. Nevertheless, all the three methods estimate that at least 60% of the groundwater basin is under moderate risk to NO 3 -N pollution, which goes up to 75% if DRASTIC or GOD-based vulnerabilities are considered as exposure pathways. Finally, based on strength and significance of correlation between the estimated risk and observed NO 3 -N concentrations, it was found that SI method is a better-suited one to assess the vulnerability and risk to groundwater pollution in the study area. Findings from this study are useful to design strategies and actions aimed to prevent nitrate pollution in groundwater of Kathmandu Valley in Nepal. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Investigating Groundwater Depletion and Aquifer Degradation in Central Valley California from Space

    Science.gov (United States)

    Ojha, C.; Shirzaei, M.; Werth, S.; Argus, D. F.

    2017-12-01

    The Central Valley in California includes one of the world's largest and yet most stressed aquifer systems. The large demand for groundwater, accelerated by population growth and extreme droughts, has been depleting the region's groundwater resources for decades. However, the lack of dense monitoring networks and inaccurate information on geophysical aquifer response pose serious challenges to water management efforts in the area and put the groundwater at high risk. Here, we performed a joint analysis of large SAR interferometric data sets acquired by ALOS L-band satellite in conjunction with the groundwater level observations across the Central Valley. We used 420 L-band SAR images acquired on the ascending orbit track during period Dec 24, 2006 - Jan 1, 2010, and generated more than 1600 interferograms with a pixel size of 100 m × 100 m. We also use data from 1600 observational wells providing continuous measurements of groundwater level within the study period for our analysis. We find that in the south and near Tulare Lake, north of Tule and south of Kaweah basin in San Joaquin valley, the subsidence rate is greatest at up to 20-25 cm/yr, while in Sacramento Valley the subsidence rate is lower at 1-3 cm/yr. From the characterization of the elastic and inelastic storage coefficients, we find that Kern, Tule, Tulare, Kaweah and Merced basins in the San Joaquin Valley are more susceptible to permanent compaction and aquifer storage loss. Kern County shows 0.23%-1.8% of aquifer storage loss during the study period, and has higher percentage loss than adjacent basins such as Tule and Tulare Lake with 0.15%-1.2% and 0.2 %-1.5% loss, respectively. Overall, we estimate that the aquifers across the valley lost a total of 28 km3 of groundwater and 2% of their storage capacity during the study period. Our unique observational evidence including valley-wide estimate of mechanical properties of aquifers and model results will not only facilitate monitoring water deficits

  8. Sulphate balance of lakes and shallow groundwater in the Vasavere buried valley, Northeast Estonia

    International Nuclear Information System (INIS)

    Erg, K.

    2003-01-01

    Groundwater is an important component of many water resource systems supplying water for domestic use, industry, and agriculture. In recent years the attention has been focused on groundwater contamination by mine water. Decline in mining activities and introduction of new technologies together with economic measures has improved the situation but much should be done during coming years. Oil shale mining brings about changes in the groundwater regime and chemical composition. The correlation between the natural (meteorological and hydrological) and technogenic (mining-technological, hydrogeological, hydrochemical) factors caused by the oil shale mining in the Vasavere valley during 1970-2000 has been studied. As a result of extensive drainage of mining shafts and water consumption, the groundwater table has noticeably lowered in the area and sulphate content in lakes and groundwater is especially high

  9. Groundwater salinity influenced by Holocene seawater trapped in incised valleys in the Red River delta plain

    Science.gov (United States)

    Larsen, Flemming; Tran, Long Vu; van Hoang, Hoan; Tran, Luu Thi; Christiansen, Anders Vest; Pham, Nhan Quy

    2017-04-01

    Salty and brackish groundwater has been observed at least 100 km inland in some aquifers contained within Quaternary delta plains. This phenomenon limits access to fresh groundwater resources, particularly in the densely populated deltas of Southeast Asia. However, the causes of inland salinity are unclear. Here we present borehole and geophysical data that show that in the Red River delta plain of Vietnam, salty and brackish groundwater primarily occurs in incised valleys that were formed during sea-level lowstands during the Pleistocene. During the mid-Holocene, these valleys were filled with fine-grained marine deposits containing trapped seawater. We conduct groundwater flow simulations that show that the age, thickness, and permeability of the marine sediments are the primary controls on the leaching of salty porewater into the freshwater aquifer. We find that salty groundwater originating from this trapped seawater is still present in Holocene-aged sediments with low permeability, and affects groundwater salinity in adjacent aquifers. In contrast, trapped seawater from all Pleistocene-aged sediments has been leached. We identify a number of brackish to saline delta aquifers elsewhere in Asia and throughout the world that have a similar sedimentary history, and thus are likely to be influenced by this leaching process.

  10. Groundwater contamination assessment for sustainable water supply in Kathmandu Valley, Nepal.

    Science.gov (United States)

    Khatlwada, N R; Takizawa, S; Tran, T V N; Inoue, M

    2002-01-01

    A study was carried out to assess the water quality situation of groundwater sources in Kathmandu Valley, Nepal. Groundwater has remained to be a major water supply source for a population of 1.5 million at present in the valley. The focus of this study was to evaluate the extent and sources of groundwater contamination. Water sampling was carried out in selected deep wells and shallow sources. The level of pollution was evaluated by comparing the water quality results with WHO guidelines. The major problems with the dug wells, hand pumps and spouts were found to be the elevated nitrate and mercury contents. The deep wells located on the central aquifer were found to have a serious threat of ammonia pollution. Deep wells were also found to have iron, manganese and mercury concentrations exceeding the guideline values. Multivariate statistical analysis was carried out to cluster the sampling sources and identify the common factors describing the potential sources and possible mechanisms associated with the contaminants. The results suggested that disintegration of the sediment organic matter under strong reducing environment leads to the origin of the unusual water qualities at the central confined aquifer. This process may be microbially mediated and occurs with the simultaneous reduction of species such as arsenic, iron, manganese and sulfate. Both natural and anthropogenic water quality problems were observed in the groundwater system of Kathmandu valley. Attention should be focused to consider distinct strategies to address these problems.

  11. Groundwater discharge by evapotranspiration, Dixie Valley, west-central Nevada, March 2009-September 2011

    Science.gov (United States)

    Garcia, C. Amanda; Huntington, Jena M; Buto, Susan G.; Moreo, Michael T.; Smith, J. LaRue; Andraski, Brian J.

    2014-01-01

    With increasing population growth and land-use change, urban communities in the desert Southwest are progressively looking toward remote basins to supplement existing water supplies. Pending applications by Churchill County for groundwater appropriations from Dixie Valley, Nevada, a primarily undeveloped basin east of the Carson Desert, have prompted a reevaluation of the quantity of naturally discharging groundwater. The objective of this study was to develop a revised, independent estimate of groundwater discharge by evapotranspiration (ETg) from Dixie Valley using a combination of eddy-covariance evapotranspiration (ET) measurements and multispectral satellite imagery. Mean annual ETg was estimated during water years 2010 and 2011 at four eddy-covariance sites. Two sites were in phreatophytic shrubland dominated by greasewood, and two sites were on a playa. Estimates of total ET and ETg were supported with vegetation cover mapping, soil physics considerations, water‑level measurements from wells, and isotopic water sourcing analyses to allow partitioning of ETg into evaporation and transpiration components. Site-based ETg estimates were scaled to the basin level by combining remotely sensed imagery with field reconnaissance. Enhanced vegetation index and brightness temperature data were compared with mapped vegetation cover to partition Dixie Valley into five discharging ET units and compute basin-scale ETg. Evapotranspiration units were defined within a delineated groundwater discharge area and were partitioned as (1) playa lake, (2) playa, (3) sparse shrubland, (4) moderate-to-dense shrubland, and (5) grassland.

  12. Calibration and Groundwater Management Scenario Analysis with the Scott Valley Integrated Hydrologic Model

    Science.gov (United States)

    Tolley, D. G.; Foglia, L.; Neumann, J.; Harter, T.

    2014-12-01

    Late summer streamflow for the Scott River in northern California has decreased approximately 50% since the mid 1960's, resulting in increased water temperatures and disconnection of certain portions of the stream which negatively impacts aquatic habitat of fish species such as coho and fall-run Chinook salmon. In collaboration with local stakeholders, the Scott Valley Integrated Hydrologic Model has been developed, which combines a water budget model and a groundwater-surface water model (MODLFOW) of the 200 km2 basin. The goal of the integrated model is to better understand the hydrologic system of the valley and explore effects of different groundwater management scenarios on late summer streamflow. The groundwater model has a quarter-hectare resolution with aggregated monthly stress periods over a 21 year period (1990-2011). The Scott River is represented using either the river (RIV) or streamflow routing (SFR) package. UCODE was used for sensitivity analysis and calibration using head observations for 52 wells in the basin and gain/loss observations for two sections of the river. Of 32 model parameters (hydraulic conductivity, specific storage, riverbed conductance and mountain recharge), 13 were found significantly sensitive to observations. Results from the calibration show excellent agreement between modeled and observed heads and to seasonal and interannual variations in streamflow. The calibrated model was used to evaluate several management scenarios: 1) alternative water budget which takes into account measured irrigation rates in the valley, 2) in-lieu recharge where surface-water instead of groundwater is used to irrigate fields near the river while streamflow is sufficiently high, and 3) managed recharge on agricultural fields in gulches on the eastern side of the valley in the winter months. Preliminary results indicate that alternative water management scenarios (in-lieu and managed recharge) significantly increase late summer streamflow by keeping

  13. Economic and Water Supply Effects of Ending Groundwater Overdraft in California's Central Valley

    Directory of Open Access Journals (Sweden)

    Timothy Nelson

    2016-03-01

    Full Text Available doi: http://dx.doi.org/10.15447/sfews.2016v14iss1art7Surface water and groundwater management are often tightly linked, even when linkage is not intended or expected. This link is especially common in semi-arid regions, such as California. This paper summarizes a modeling study on the effects of ending long-term overdraft in California’s Central Valley, the state’s largest aquifer system. The study focuses on economic and operational aspects, such as surface water pumping and diversions, groundwater recharge, water scarcity, and the associated operating and water scarcity costs. This analysis uses CALVIN, a hydro-economic optimization model for California’s water resource system that suggests operational changes to minimize net system costs for a given set of conditions, such as ending long-term overdraft. Based on model results, ending overdraft might induce some major statewide operational changes, including large increases to Delta exports, more intensive conjunctive-use operations with increasing artificial and in-lieu recharge, and greater water scarcity for Central Valley agriculture. The statewide costs of ending roughly 1.2 maf yr-1 of groundwater overdraft are at least $50 million per year from additional direct water shortage and additional operating costs. At its worst, the costs of ending Central Valley overdraft could be much higher, perhaps comparable to the recent economic effects of drought. Driven by recent state legislation to improve groundwater sustainability, ending groundwater overdraft has important implications statewide for water use and management, particularly in the Sacramento–San Joaquin Delta. Ending Central Valley overdraft will amplify economic pressure to increase Delta water exports rather than reduce them, tying together two of California’s largest water management problems.

  14. Baseline risk assessment for groundwater contamination at the uranium mill tailings site near Monument Valley, Arizona

    International Nuclear Information System (INIS)

    1993-09-01

    This baseline risk assessment evaluates potential impact to public health or the environment resulting from groundwater contamination at the former uranium mill processing site near Monument Valley, Arizona. The tailings and other contaminated material at this site are being relocated and stabilized in a disposal cell at Mexican Hat, Utah, through the US Department of Energy (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. The tailings removal is planned for completion by spring 1994. After the tailings are removed, groundwater contamination at the site will continue to be evaluated. This risk assessment is the first document specific to this site for the Groundwater Project. It will be used to assist in determining what remedial action is needed for contaminated groundwater at the site

  15. Hydrogeologic and geochemical characterization of groundwater resources in Rush Valley, Tooele County, Utah

    Science.gov (United States)

    Gardner, Philip M.; Kirby, Stefan

    2011-01-01

    The water resources of Rush Valley were assessed during 2008–2010 with an emphasis on refining the understanding of the groundwater-flow system and updating the groundwater budget. Surface-water resources within Rush Valley are limited and are generally used for agriculture. Groundwater is the principal water source for most other uses including supplementing irrigation. Most groundwater withdrawal in Rush Valley is from the unconsolidated basin-fill aquifer where conditions are generally unconfined near the mountain front and confined at lower altitudes near the valley center. Productive aquifers also occur in fractured bedrock along the valley margins and beneath the basin-fill deposits in some areas.Drillers’ logs and geophysical gravity data were compiled and used to delineate seven hydrogeologic units important to basin-wide groundwater movement. The principal basin-fill aquifer includes the unconsolidated Quaternary-age alluvial and lacustrine deposits of (1) the upper basin-fill aquifer unit (UBFAU) and the consolidated and semiconsolidated Tertiary-age lacustrine and alluvial deposits of (2) the lower basin-fill aquifer unit (LBFAU). Bedrock hydrogeologic units include (3) the Tertiary-age volcanic unit (VU), (4) the Pennsylvanian- to Permian-age upper carbonate aquifer unit (UCAU), (5) the upper Mississippian- to lower Pennsylvanian-age upper siliciclastic confining unit (USCU), (6) the Middle Cambrian- to Mississippian-age lower carbonate aquifer unit (LCAU), and (7) the Precambrian- to Lower Cambrian-age noncarbonate confining unit (NCCU). Most productive bedrock wells in the Rush Valley groundwater basin are in the UCAU.Average annual recharge to the Rush Valley groundwater basin is estimated to be about 39,000 acre-feet. Nearly all recharge occurs as direct infiltration of snowmelt and rainfall within the mountains with smaller amounts occurring as infiltration of streamflow and unconsumed irrigation water at or near the mountain front. Groundwater

  16. Anthropogenic Influence On Groundwater Quality In Jericho and And Adjoining Wadis (Lower Jordan Valley, Palestine)

    Science.gov (United States)

    Geyer, S.; Khayat, S.; Roediger, T.; Siebert, C.

    2008-12-01

    The Lower Jordan Valley is part of the Jordan-Dead Sea Rift. The graben is filled by sedmiments of limnological and marine origin. Towards the Dead Sea, the occurance of gipseous and salty sediments on the valley floor increase. The southern part of the Lower Jordan Valley, where the city of Jericho is situated, is an arid area (SMART-project, is to understand the vulnerability of the Jericho groundwater aquifers in connection with lowering the groundwater table by overexploitation and the intensively use of pesticides Jericho and its vicinity are of most importance for the Palestinians. However, beside the about 25,000 residents, the tourism industry and the vital agriculture depend on sufficient and expoitable fresh water resources. Because the demand of water is increasing, overexpoitaion takes place. Due to over extraction of groundwater a huge depression cone is evolving during the dry season which is filled up again according to the groundwater recharge in the rainy season. Concomitantly, depression cone in the fresh water aquifers leads to an infiltration of the surrounding saltwater. The amount of saltwater which infiltrates into the freshwater resource was calculated by different stable isotope methods (d2H, d18O) and hydrochemical analyses of wellwater. The agriculture is main consumer of groundwater - over 60% of the pumped water is used for inefficient irrigation. Additionally, an intensive use of pesticides in concentrated liquid and gaseous forms for vegetable gardening hold the danger to pollute the groundwater via irrigation return flow. This return flow most probably endangers the quality of the water resource, because shallow wells nearby extract it directly from the underground. However, one result of the first screening campaign concerning pesticide remnants in the groundwater wells of Jericho, just traces have been detected. Thus, the higher amount of chemicals is retained by the soil during infiltration of irrigated water. The detected low

  17. Updated comparison of groundwater flow model results and isotopic data in the Leon Valley, Mexico

    Science.gov (United States)

    Hernandez-Garcia, G. D.

    2015-12-01

    Northwest of Mexico City, the study area is located in the State of Guanajuato. Leon Valley has covered with groundwater its demand of water, estimated in 20.6 cubic meters per second. The constant increase of population and economic activities in the region, mainly in cities and automobile factories, has also a constant growth in water needs. Related extraction rate has produced an average decrease of approximately 1.0 m per year over the past two decades. This suggests that the present management of the groundwater should be checked. Management of groundwater in the study area involves the possibility of producing environmental impacts by extraction. This vital resource under stress becomes necessary studying its hydrogeological functioning to achieve scientific management of groundwater in the Valley. This research was based on the analysis and integration of existing information and the field generated by the authors. On the base of updated concepts like the geological structure of the area, the hydraulic parameters and the composition of deuterium-delta and delta-oxygen -18, this research has new results. This information has been fully analyzed by applying a groundwater flow model with particle tracking: the result has also a similar result in terms of travel time and paths derived from isotopic data.

  18. A groundwater-flow model for the Treasure Valley and surrounding area, southwestern Idaho

    Science.gov (United States)

    Bartolino, James R.; Vincent, Sean

    2017-04-17

    The U.S. Geological Survey (USGS), in partnership with the Idaho Department of Water Resources (IDWR) and Idaho Water Resource Board (IWRB), will construct a numerical groundwater-flow model of the Treasure Valley and surrounding area. Resource managers will use the model to simulate potential anthropogenic and climatic effects on groundwater for water-supply planning and management. As part of model construction, the hydrogeologic understanding of the aquifer system will be updated with information collected during the last two decades, as well as new data collected for the study.

  19. Initial characterization of the groundwater system near the Lower Colorado Water Supply Project, Imperial Valley, California

    Science.gov (United States)

    Coes, Alissa L.; Land, Michael; Densmore, Jill N.; Landrum, Michael T.; Beisner, Kimberly R.; Kennedy, Jeffrey R.; Macy, Jamie P.; Tillman, Fred D.

    2015-01-01

    In 2009, the U.S. Geological Survey, in cooperation with the city of Needles, began a study of the hydrogeology along the All-American Canal, which conveys water from the Colorado River to the Imperial Valley. The focus of this study was to gain a better understanding of the effect of lining the All-American Canal, and other management actions, on future total dissolved solids concentrations in groundwater pumped by Lower Colorado Water Supply Project wells that is delivered to the All-American Canal. The study included the compilation and evaluation of previously published hydrogeologic and geochemical information, establishment of a groundwater-elevation and groundwater-quality monitoring network, results of monitoring groundwater elevations and groundwater quality from 2009 to 2011, site-specific hydrologic investigations of the Lower Colorado Water Supply Project area, examination of groundwater salinity by depth by using time-domain electromagnetic surveys, and monitoring of groundwater-storage change by using microgravity methods. 

  20. Ground-Water Modeling of the Death Valley Region, Nevada and California

    International Nuclear Information System (INIS)

    USGS

    2006-01-01

    Water is a precious commodity, especially in the arid southwest region of the US, where there is a limited supply of both surface water and ground water. Ground water has a variety of uses (such as agricultural, commercial, and domestic) in the Death Valley regional ground-water flow system (DVRFS) of southern Nevada and eastern California. The DVRFS, an area of about 100,000 square kilometers, contains very complex geology and hydrology. Using a computer model to represent this complex system the US Geological Survey (USGS) simulated ground-water flow in the Death Valley region for use with US Department of Energy (DOE) projects in southern Nevada. The model was created to help address contaminant cleanup activities associated with the underground nuclear testing conducted from 1951 to 1992 at the Nevada Test Site and to support the licensing process for the Nation's proposed geologic repository for high-level nuclear waste at Yucca Mountain, Nevada

  1. Chronology, sedimentology, and microfauna of groundwater discharge deposits in the central Mojave Desert, Valley Wells, California

    Science.gov (United States)

    Pigati, Jeffrey S.; Miller, David M.; Bright, Jordon E.; Mahan, Shannon; Nekola, Jeffrey C.; Paces, James B.

    2011-01-01

    During the late Pleistocene, emergent groundwater supported persistent and long-lived desert wetlands in many broad valleys and basins in the American Southwest. When active, these systems provided important food and water sources for local fauna, supported hydrophilic and phreatophytic vegetation, and acted as catchments for eolian and alluvial sediments. Desert wetlands are represented in the geologic record by groundwater discharge deposits, which are also called spring or wetland deposits. Groundwater discharge deposits contain information on the timing and magnitude of past changes in water-table levels and, thus, are a source of paleohydrologic and paleoclimatic information. Here, we present the results of an investigation of extensive groundwater discharge deposits in the central Mojave Desert at Valley Wells, California. We used geologic mapping and stratigraphic relations to identify two distinct wetland sequences at Valley Wells, which we dated using radiocarbon, luminescence, and uranium-series techniques. We also analyzed the sediments and microfauna (ostracodes and gastropods) to reconstruct the specific environments in which they formed. Our results suggest that the earliest episode of high water-table conditions at Valley Wells began ca. 60 ka (thousands of calendar yr B.P.), and culminated in peak discharge between ca. 40 and 35 ka. During this time, cold (4–12 °C) emergent groundwater supported extensive wetlands that likely were composed of a wet, sedge-rush-tussock meadow mixed with mesic riparian forest. After ca. 35 ka, the water table dropped below the ground surface but was still shallow enough to support dense stands of phreatophytes through the Last Glacial Maximum (LGM). The water table dropped further after the LGM, and xeric conditions prevailed until modest wetlands returned briefly during the Younger Dryas cold event (13.0–11.6 ka). We did not observe any evidence of wet conditions during the Holocene at Valley Wells. The timing

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

    Science.gov (United States)

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

    2014-12-01

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

  3. Effect of faulting on ground-water movement in the Death Valley region, Nevada and California

    Energy Technology Data Exchange (ETDEWEB)

    Faunt, C.C.

    1997-12-31

    This study characterizes the hydrogeologic system of the Death Valley region, an area covering approximately 100,000 square kilometers. The study also characterizes the effects of faults on ground-water movement in the Death Valley region by synthesizing crustal stress, fracture mechanics,a nd structural geologic data. The geologic conditions are typical of the Basin and Range Province; a variety of sedimentary and igneous intrusive and extrusive rocks have been subjected to both compressional and extensional deformation. Faulting and associated fracturing is pervasive and greatly affects ground-water flow patterns. Faults may become preferred conduits or barriers to flow depending on whether they are in relative tension, compression, or shear and other factors such as the degree of dislocations of geologic units caused by faulting, the rock types involved, the fault zone materials, and the depth below the surface. The current crustal stress field was combined with fault orientations to predict potential effects of faults on the regional ground-water flow regime. Numerous examples of fault-controlled ground-water flow exist within the study area. Hydrologic data provided an independent method for checking some of the assumptions concerning preferential flow paths. 97 refs., 20 figs., 5 tabs.

  4. Effect of faulting on ground-water movement in the Death Valley region, Nevada and California

    International Nuclear Information System (INIS)

    Faunt, C.C.

    1997-01-01

    This study characterizes the hydrogeologic system of the Death Valley region, an area covering approximately 100,000 square kilometers. The study also characterizes the effects of faults on ground-water movement in the Death Valley region by synthesizing crustal stress, fracture mechanics,a nd structural geologic data. The geologic conditions are typical of the Basin and Range Province; a variety of sedimentary and igneous intrusive and extrusive rocks have been subjected to both compressional and extensional deformation. Faulting and associated fracturing is pervasive and greatly affects ground-water flow patterns. Faults may become preferred conduits or barriers to flow depending on whether they are in relative tension, compression, or shear and other factors such as the degree of dislocations of geologic units caused by faulting, the rock types involved, the fault zone materials, and the depth below the surface. The current crustal stress field was combined with fault orientations to predict potential effects of faults on the regional ground-water flow regime. Numerous examples of fault-controlled ground-water flow exist within the study area. Hydrologic data provided an independent method for checking some of the assumptions concerning preferential flow paths. 97 refs., 20 figs., 5 tabs

  5. Dissolved phosphorus distribution in shallow groundwater beneath dairy farms, Central Valley, California

    Science.gov (United States)

    Young, M. B.; Lockhart, K.; Holstege, D.; Applegate, O.; Harter, T.

    2012-12-01

    Concentrated animal farming operations (CAFOs) often produce surface runoff with high phosphorus (P) concentrations, but much less is known about P leaching and distributions in shallow groundwater beneath CAFOs. In this study, concentrations of soluble P were measured in shallow groundwater beneath ten dairies located in the Central Valley, California between 1998 and 2009 to assess spatial and temporal variability in areas of higher and lower hydrogeological vulnerability to groundwater contamination, and to investigate both land uses and physiochemical parameters associated with soluble P distribution. Distribution of bioavailable soil phosphate (bicarbonate extraction) was also examined in soil cores from several of the dairies in order to asses potential links between P distribution in the vadose zone and dissolved P concentrations near the top of the groundwater table. Dissolved P and other geochemical constituents were measured in 200 domestic drinking water wells to examine differences in shallow and deeper groundwater within the region. Samples from dairies and domestic wells were collected from two distinct regions in the Central Valley. The northern region (northeastern San Joaquin Valley) is characterized by a shallower water table, sandy soils, and groundwater discharges to surface water, whereas the southern region (Tulare Lake Basin) is characterized by a much deeper water table and does not have natural discharges of groundwater to surface water. Mean dissolved P concentrations were highest in the two dairies with the shallowest water table and sandiest soils, although dissolved P concentrations were highly variable across monitoring wells within individual dairies. Dissolved P ranged from below detection (waste lagoons, corrals, and manured fields); however phosphate concentrations in soil cores appeared to be strongly influenced by dairy land use, with the highest values occurring in cores adjacent to waste lagoons, followed by cores taken from

  6. Groundwater quality in the Madera and Chowchilla subbasins of the San Joaquin Valley, California

    Science.gov (United States)

    Shelton, Jennifer L.; Fram, Miranda S.; Belitz, Kenneth

    2013-01-01

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s untreated groundwater quality and increases public access to groundwater-quality information. The Madera and Chowchilla subbasins of the San Joaquin Valley constitute one of the study units being evaluated. The Madera-Chowchilla study unit is about 860 square miles and consists of the Madera and Chowchilla groundwater subbasins of the San Joaquin Valley Basin (California Department of Water Resources, 2003; Shelton and others, 2009). The study unit has hot, dry summers and cool, moist winters. Average annual rainfall ranges from 11 to 15 inches, most of which occurs between November and February. The main surface-water features in the study unit are the San Joaquin, Fresno, and Chowchilla Rivers, and the Madera and Chowchilla canals. Land use in the study unit is about 69 percent (%) agricultural, 28% natural (mainly grasslands), and 3% urban. The primary crops are orchards and vineyards. The largest urban area is the city of Madera. The primary aquifer system is defined as those parts of the aquifer corresponding to the perforated intervals of wells listed in the California Department of Public Health (CDPH) database. In the Madera-Chowchilla study unit, these wells typically are drilled to depths between 200 and 800 feet, consist of a solid casing from land surface to a depth of about 140 to 400 feet, and are perforated below the solid casing. Water quality in the primary aquifer system may differ from that in the shallower and deeper parts of the aquifer system. The primary aquifer system in the study unit consists of Quaternary-age alluvial-fan and fluvial deposits that were formed by the rivers draining the Sierra Nevada. Sediments consist of gravels, sands

  7. Groundwater quality in the Western San Joaquin Valley study unit, 2010: California GAMA Priority Basin Project

    Science.gov (United States)

    Fram, Miranda S.

    2017-06-09

    Water quality in groundwater resources used for public drinking-water supply in the Western San Joaquin Valley (WSJV) was investigated by the USGS in cooperation with the California State Water Resources Control Board (SWRCB) as part of its Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin Project. The WSJV includes two study areas: the Delta–Mendota and Westside subbasins of the San Joaquin Valley groundwater basin. Study objectives for the WSJV study unit included two assessment types: (1) a status assessment yielding quantitative estimates of the current (2010) status of groundwater quality in the groundwater resources used for public drinking water, and (2) an evaluation of natural and anthropogenic factors that could be affecting the groundwater quality. The assessments characterized the quality of untreated groundwater, not the quality of treated drinking water delivered to consumers by water distributors.The status assessment was based on data collected from 43 wells sampled by the U.S. Geological Survey for the GAMA Priority Basin Project (USGS-GAMA) in 2010 and data compiled in the SWRCB Division of Drinking Water (SWRCB-DDW) database for 74 additional public-supply wells sampled for regulatory compliance purposes between 2007 and 2010. To provide context, concentrations of constituents measured in groundwater were compared to U.S. Environmental Protection Agency (EPA) and SWRCB-DDW regulatory and non-regulatory benchmarks for drinking-water quality. The status assessment used a spatially weighted, grid-based method to estimate the proportion of the groundwater resources used for public drinking water that has concentrations for particular constituents or class of constituents approaching or above benchmark concentrations. This method provides statistically unbiased results at the study-area scale within the WSJV study unit, and permits comparison of the two study areas to other areas assessed by the GAMA Priority Basin Project

  8. Environmental impacts of groundwater extraction at the Drentsche Aa brook valley. Vegetation development and greenhouse gas emission reductions of rewetting measures.

    NARCIS (Netherlands)

    Hoetz, Christiaan

    2013-01-01

    Summary The Drentsche Aa brook valley contains various valuable ecosystems and harbours many rare species. Groundwater is extracted in the area to produce drinking water. This affects the local ecosystems by reducing groundwater exfiltration, which can c

  9. Shallow groundwater in the Matanuska-Susitna Valley, Alaska—Conceptualization and simulation of flow

    Science.gov (United States)

    Kikuchi, Colin P.

    2013-01-01

    The Matanuska-Susitna Valley is in the Upper Cook Inlet Basin and is currently undergoing rapid population growth outside of municipal water and sewer service areas. In response to concerns about the effects of increasing water use on future groundwater availability, a study was initiated between the Alaska Department of Natural Resources and the U.S. Geological Survey. The goals of the study were (1) to compile existing data and collect new data to support hydrogeologic conceptualization of the study area, and (2) to develop a groundwater flow model to simulate flow dynamics important at the regional scale. The purpose of the groundwater flow model is to provide a scientific framework for analysis of regional-scale groundwater availability. To address the first study goal, subsurface lithologic data were compiled into a database and were used to construct a regional hydrogeologic framework model describing the extent and thickness of hydrogeologic units in the Matanuska-Susitna Valley. The hydrogeologic framework model synthesizes existing maps of surficial geology and conceptual geochronologies developed in the study area with the distribution of lithologies encountered in hundreds of boreholes. The geologic modeling package Geological Surveying and Investigation in Three Dimensions (GSI3D) was used to construct the hydrogeologic framework model. In addition to characterizing the hydrogeologic framework, major groundwater-budget components were quantified using several different techniques. A land-surface model known as the Deep Percolation Model was used to estimate in-place groundwater recharge across the study area. This model incorporates data on topography, soils, vegetation, and climate. Model-simulated surface runoff was consistent with observed streamflow at U.S. Geological Survey streamgages. Groundwater withdrawals were estimated on the basis of records from major water suppliers during 2004-2010. Fluxes between groundwater and surface water were

  10. Groundwater Quality and Nitrogen Use Efficiency in Nebraska's Central Platte River Valley.

    Science.gov (United States)

    Ferguson, Richard B

    2015-03-01

    Groundwater nitrate contamination has been an issue in the Platte River Valley of Nebraska since the 1960s, with groundwater nitrate-N concentrations frequently in excess of 10 mg L. This article summarizes education and regulatory efforts to reduce the environmental impact of irrigated crop production in the Platte River Valley. In 1988, a Groundwater Management Area (GWMA) was implemented in the Central Platte Natural Resources District to encourage adoption of improved management practices. Since 1988, there have been steady declines in average groundwater nitrate-N concentrations of about 0.15 mg NO-N L yr in much of the GWMA (from 19 to 15 mg NO-N L). However, N use efficiency (NUE) (partial factor productivity for N [PFP]) has increased very little from 1988 to 2012 (60-65 kg grain kg N), whereas statewide PFP increased from 49 to 67 kg grain kg N in the same period. Although growers are encouraged to credit N from sources besides fertilizer (e.g., soil residual, legumes, irrigation water, and manure), confidence in and use of credits tended to decrease as credits became larger; there was a tendency toward an average N rate regardless of credit-based recommendations. This information, coupled with data from other studies, suggests that much of the decline in groundwater nitrate can be attributed to improved irrigation management-especially conversion from furrow to sprinkler irrigation-and to a lesser extent to improved timing of N application. The development and adoption of improved N management practices, such as fertigation, controlled-release N formulation, and use of crop canopy sensors for in-season N application may be required for further significant NUE gains in these irrigated systems. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  11. Characterization of source rocks and groundwater radioactivity at the Chihuahua valley

    International Nuclear Information System (INIS)

    Renteria V, M.; Montero C, M.E.; Reyes C, M.; Herrera P, E.F.; Valenzuela H, M.; Rodriguez P, A.; Manjon C, G.; Garcia T, R.; Crespo, T.

    2007-01-01

    As part of a scientific research project about alpha radioactivity in groundwater for human consumption at the Chihuahua City, the characterization of rock sources of radioactivity around de Chihuahua valley was developed. The radioactivity of groundwater and sediments was determined, too. The radioactivity of uranium- and thorium- series isotopes contained in rocks was obtained by high resolution gamma-ray spectroscopy. Some representative values are 50 Bq/kg for the mean value of Bi-214 activity, and 121.5 Bq/kg for the highest value at West of the city. The activity of sediments, extracted during wells perforation, was determined using a Nal(TI) detector. A non-reported before uranium ore was localized at the San Marcos range formation. Its outcrops are inside the Chihuahua-Sacramento valley basin and its activity characterization was performed. Unusually high specific uranium activities, determined by alpha spectrometry, were obtained in water, plants, sediments and fish extracted at locations close to outcrops of uranium minerals. The activity of water of the San Marcos dam reached 7.7 Bq/L. The activity of fish, trapped at San Marcos dam, is 0.99 Bq/kg. Conclusions about the contamination of groundwater at North of Chihuahua City were obtained. (Author)

  12. Characterization of source rocks and groundwater radioactivity at the Chihuahua valley

    Energy Technology Data Exchange (ETDEWEB)

    Renteria V, M.; Montero C, M.E.; Reyes C, M.; Herrera P, E.F.; Valenzuela H, M. [Centro de lnvestigacion en Materiales Avanzados, Miguel de Cervantes 120, 31109 Chihuahua, (Mexico); Rodriguez P, A. [World Wildlife Fund (WWF), Chihuahuan Desert Program, Coronado 1005, 31000 Chihuahua (Mexico); Manjon C, G.; Garcia T, R. [Universidad de Sevilla, Departamento de Fisica Aplicada 11, ETS Arquitectura, Av. Reina Mercedes 2, 41012 Sevilla, (Spain); Crespo, T. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Av. Complutense 22, 28040 Madrid, (Spain)]. e-mail: elena.montero@cimav.edu.mx

    2007-07-01

    As part of a scientific research project about alpha radioactivity in groundwater for human consumption at the Chihuahua City, the characterization of rock sources of radioactivity around de Chihuahua valley was developed. The radioactivity of groundwater and sediments was determined, too. The radioactivity of uranium- and thorium- series isotopes contained in rocks was obtained by high resolution gamma-ray spectroscopy. Some representative values are 50 Bq/kg for the mean value of Bi-214 activity, and 121.5 Bq/kg for the highest value at West of the city. The activity of sediments, extracted during wells perforation, was determined using a Nal(TI) detector. A non-reported before uranium ore was localized at the San Marcos range formation. Its outcrops are inside the Chihuahua-Sacramento valley basin and its activity characterization was performed. Unusually high specific uranium activities, determined by alpha spectrometry, were obtained in water, plants, sediments and fish extracted at locations close to outcrops of uranium minerals. The activity of water of the San Marcos dam reached 7.7 Bq/L. The activity of fish, trapped at San Marcos dam, is 0.99 Bq/kg. Conclusions about the contamination of groundwater at North of Chihuahua City were obtained. (Author)

  13. Deep groundwater and potential subsurface habitats beneath an Antarctic dry valley.

    Science.gov (United States)

    Mikucki, J A; Auken, E; Tulaczyk, S; Virginia, R A; Schamper, C; Sørensen, K I; Doran, P T; Dugan, H; Foley, N

    2015-04-28

    The occurrence of groundwater in Antarctica, particularly in the ice-free regions and along the coastal margins is poorly understood. Here we use an airborne transient electromagnetic (AEM) sensor to produce extensive imagery of resistivity beneath Taylor Valley. Regional-scale zones of low subsurface resistivity were detected that are inconsistent with the high resistivity of glacier ice or dry permafrost in this region. We interpret these results as an indication that liquid, with sufficiently high solute content, exists at temperatures well below freezing and considered within the range suitable for microbial life. These inferred brines are widespread within permafrost and extend below glaciers and lakes. One system emanates from below Taylor Glacier into Lake Bonney and a second system connects the ocean with the eastern 18 km of the valley. A connection between these two basins was not detected to the depth limitation of the AEM survey (∼350 m).

  14. Groundwater quality in the shallow aquifers of the Madera–Chowchilla and Kings subbasins, San Joaquin Valley, California

    Science.gov (United States)

    Fram, Miranda S.; Shelton, Jennifer L.

    2018-01-08

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Program’s Priority Basin Project assesses the quality of groundwater resources used for drinking-water supply and increases public access to groundwater-quality information. Many households and small communities in the Madera– Chowchilla and Kings subbasins of the San Joaquin Valley rely on private domestic wells for their drinking-water supplies.

  15. Deep groundwater and potential subsurface habitats beneath an Antarctic dry valley

    DEFF Research Database (Denmark)

    Mikucki, J. A.; Auken, E.; Tulaczyk, S.

    2015-01-01

    subsurface resistivity were detected that are inconsistent with the high resistivity of glacier ice or dry permafrost in this region. We interpret these results as an indication that liquid, with sufficiently high solute content, exists at temperatures well below freezing and considered within the range......The occurrence of groundwater in Antarctica, particularly in the ice-free regions and along the coastal margins is poorly understood. Here we use an airborne transient electromagnetic (AEM) sensor to produce extensive imagery of resistivity beneath Taylor Valley. Regional-scale zones of low...

  16. Death Valley regional groundwater flow model calibration using optimal parameter estimation methods and geoscientific information systems

    Science.gov (United States)

    D'Agnese, F. A.; Faunt, C.C.; Hill, M.C.; Turner, A.K.

    1996-01-01

    A three-layer Death Valley regional groundwater flow model was constructed to evaluate potential regional groundwater flow paths in the vicinity of Yucca Mountain, Nevada. Geoscientific information systems were used to characterize the complex surface and subsurface hydrogeological conditions of the area, and this characterization was used to construct likely conceptual models of the flow system. The high contrasts and abrupt contacts of the different hydrogeological units in the subsurface make zonation the logical choice for representing the hydraulic conductivity distribution. Hydraulic head and spring flow data were used to test different conceptual models by using nonlinear regression to determine parameter values that currently provide the best match between the measured and simulated heads and flows.

  17. Groundwater vulnerability assessment in Jaworzynka's Valley catchment basin (Tatra Mountains, Poland)

    Science.gov (United States)

    Cypel, M.

    2012-04-01

    During the research an attempt was made to assess an intrinsic groundwater vulnerability to contamination in Tatra Mountains (Poland. Assessment of the degree of hazard of permeating pollutions from land surface directly to the ground water table was the main target of the research. The Jaworzynka's Valley in West Tatra Mountains was chosen as the exact research area. Jaworzynka's Valley is a typical karst catchment basin. Location of study area wasn't accidental, because in the north part of the valley there is a well which is being used as drinking water intake for the whole Zakopane City. This is the reason, why the quality of ground water is so important. The method used in this research, entitled KARSTIC, wasn't applied in Poland before. This is a parametric method of groundwater vulnerability assessment. KARSTIC is a modification of much better known DRASTIC method, specialized for specific karst terrain. KARSTIC method created by A. Davis and others (1994), was used for the first time, during a research in the Black Hills Mountains, USA. Research in Jaworzynka's Valley was based on the Black Hills study. In order to apply this method in Tatra Mountains, it was necessary to make a few changes in relation to original area. Applying KARSTIC method consists of successive stages. Schematization of hydrogeological conditions is an inseparable part of KARSTIC method. The first step bases on collecting all of available data such as maps, databases and documentations. Next stage consists of classifying all parameters employed in this method and then assigning a ratings and weights for this parameters. Subsequently it is necessary to use a mathematical formula, named Pollution Potential Index, which presents a ground water vulnerability in each point. The final step is visualization on the ground water vulnerability map. The result of research displays the high vulnerability in close proximity of the drinking water intake. The most vulnerable areas in Jaworzynka

  18. The use of natural isotopes for identifying the origins of groundwater flows: Drentsche Aa Brook Valley, The Netherlands.

    Science.gov (United States)

    Elshehawi, Samer; Grootjans, Ab; Bregman, Enno

    2017-04-01

    This paper investigates the origin of various groundwater flows in a small brook valley reserve Drentsche Aa Valley in the northern part of the Netherlands. The aim was also to validate a hydrological model that simulated coupled particle flow in this area and also incorporated different scenarios for groundwater abstraction in order to predict future implications of groundwater abstraction on ecological values. Water samples from various sites and depths were analysed for macro-ionic composition, stable isotopes (2H and 18O) and also 14C. Three sites have 14C activities over 100%, indicating very recent water. The main groundwater discharge areas showed inflow of old groundwater up to 5000 years. Inflow of different groundwater flows of various ages could be detected most clearly from the 14C data. Downstream area that were affected by groundwater abstraction showed distinct infiltration characteristics, both in macro-ionic composition and contents of natural isotopes, to a depth of 6m below surface In the main exfiltration areas, we found that at 95 meters below the surface, the groundwater was characterized by a NaCl type groundwater facies. But the absolute concentrations were not high enough to conclude that double diffusive convection (DDC) near a salt diapir was responsible for this effect.

  19. Knowledge, transparency, and refutability in groundwater models, an example from the Death Valley regional groundwater flow system

    Science.gov (United States)

    Hill, Mary C.; Faunt, Claudia C.; Belcher, Wayne; Sweetkind, Donald; Tiedeman, Claire; Kavetski, Dmitri

    2013-01-01

    This work demonstrates how available knowledge can be used to build more transparent and refutable computer models of groundwater systems. The Death Valley regional groundwater flow system, which surrounds a proposed site for a high level nuclear waste repository of the United States of America, and the Nevada National Security Site (NNSS), where nuclear weapons were tested, is used to explore model adequacy, identify parameters important to (and informed by) observations, and identify existing old and potential new observations important to predictions. Model development is pursued using a set of fundamental questions addressed with carefully designed metrics. Critical methods include using a hydrogeologic model, managing model nonlinearity by designing models that are robust while maintaining realism, using error-based weighting to combine disparate types of data, and identifying important and unimportant parameters and observations and optimizing parameter values with computationally frugal schemes. The frugal schemes employed in this study require relatively few (10–1000 s), parallelizable model runs. This is beneficial because models able to approximate the complex site geology defensibly tend to have high computational cost. The issue of model defensibility is particularly important given the contentious political issues involved.

  20. Knowledge, transparency, and refutability in groundwater models, an example from the Death Valley regional groundwater flow system

    Science.gov (United States)

    Hill, Mary C.; Faunt, Claudia C.; Belcher, Wayne R.; Sweetkind, Donald S.; Tiedeman, Claire R.; Kavetski, Dmitri

    This work demonstrates how available knowledge can be used to build more transparent and refutable computer models of groundwater systems. The Death Valley regional groundwater flow system, which surrounds a proposed site for a high level nuclear waste repository of the United States of America, and the Nevada National Security Site (NNSS), where nuclear weapons were tested, is used to explore model adequacy, identify parameters important to (and informed by) observations, and identify existing old and potential new observations important to predictions. Model development is pursued using a set of fundamental questions addressed with carefully designed metrics. Critical methods include using a hydrogeologic model, managing model nonlinearity by designing models that are robust while maintaining realism, using error-based weighting to combine disparate types of data, and identifying important and unimportant parameters and observations and optimizing parameter values with computationally frugal schemes. The frugal schemes employed in this study require relatively few (10-1000 s), parallelizable model runs. This is beneficial because models able to approximate the complex site geology defensibly tend to have high computational cost. The issue of model defensibility is particularly important given the contentious political issues involved.

  1. Groundwater influence on water budget of a small constructed floodplain wetland in the Ridge and Valley of Virginia, USA

    OpenAIRE

    Ludwig, Andrea L.; Hession, W. Cully

    2015-01-01

    Study region: A floodplain in the headwaters of a tributary to the Chesapeake Bay, Ridge and Valley of the Eastern United States. Study focus: This study investigated the influence of groundwater exchange in the annual wetland hydrologic budget and identified spatial and temporal variability in groundwater hydraulic gradients using an array of nested piezometers. New hydrological insights for the region: Data showed that the created wetland met hydrologic success criteria, and that t...

  2. Modeling the long-term fate of agricultural nitrate in groundwater in the San Joaquin Valley, California

    Science.gov (United States)

    Chapelle, Francis H.; Campbell, Bruce G.; Widdowson, Mark A.; Landon, Mathew K.

    2013-01-01

    Nitrate contamination of groundwater systems used for human water supplies is a major environmental problem in many parts of the world. Fertilizers containing a variety of reduced nitrogen compounds are commonly added to soils to increase agricultural yields. But the amount of nitrogen added during fertilization typically exceeds the amount of nitrogen taken up by crops. Oxidation of reduced nitrogen compounds present in residual fertilizers can produce substantial amounts of nitrate which can be transported to the underlying water table. Because nitrate concentrations exceeding 10 mg/L in drinking water can have a variety of deleterious effects for humans, agriculturally derived nitrate contamination of groundwater can be a serious public health issue. The Central Valley aquifer of California accounts for 13 percent of all the groundwater withdrawals in the United States. The Central Valley, which includes the San Joaquin Valley, is one of the most productive agricultural areas in the world and much of this groundwater is used for crop irrigation. However, rapid urbanization has led to increasing groundwater withdrawals for municipal public water supplies. That, in turn, has led to concern about how contaminants associated with agricultural practices will affect the chemical quality of groundwater in the San Joaquin Valley. Crop fertilization with various forms of nitrogen-containing compounds can greatly increase agricultural yields. However, leaching of nitrate from soils due to irrigation has led to substantial nitrate contamination of shallow groundwater. That shallow nitrate-contaminated groundwater has been moving deeper into the Central Valley aquifer since the 1960s. Denitrification can be an important process limiting the mobility of nitrate in groundwater systems. However, substantial denitrification requires adequate sources of electron donors in order to drive the process. In many cases, dissolved organic carbon (DOC) and particulate organic carbon

  3. wrv: An R Package for Groundwater Flow Model Construction, Wood River Valley Aquifer System, Idaho

    Science.gov (United States)

    Fisher, J. C.

    2014-12-01

    Groundwater models are one of the main tools used in the hydrogeological sciences to assess resources and to simulate possible effects from future water demands and changes in climate. The hydrological inputs to groundwater models can be numerous and can vary in both time and space. Difficulties associated with model construction are often related to extensive datasets and cumbersome data processing tasks. To mitigate these difficulties, a graphical user interface (GUI) is often employed to aid the input of data for creating models. Unfortunately, GUI software presents an obstacle to reproducibility, a cornerstone of research. The considerable effort required to document processing steps in a GUI program, and the rapid obsoleteness of these steps with subsequent versions of the software, has prompted modelers to explicitly write down processing steps as source code to make them 'easily' reproducible. This research describes the R package wrv, a collection of datasets and functions for pre- and post-processing the numerical groundwater flow model of the Wood River Valley aquifer system, south-central Idaho. R largely facilitates reproducible modeling with the package vignette; a document that is a combination of content and source code. The code is run when the vignette is built, and all data analysis output (such as figures and tables) is created on the fly and inserted into the final document. The wrv package includes two vignettes that explain and run steps that (1) create package datasets from raw data files located on a publicly accessible repository, and (2) create and run the groundwater flow model. MODFLOW-USG, the numerical groundwater model used in this study, is executed from the vignette, and model output is returned for exploratory analyses. The ability of R to perform all processing steps in a single workflow is attributed to its comprehensive list of features; that include geographic information system and time series functionality.

  4. Ground-water flow and simulated effects of development in Paradise Valley, a basin tributary to the Humboldt River in Humboldt County, Nevada

    Science.gov (United States)

    Prudic, David E.; Herman, M.E.

    1996-01-01

    A computer model was used to characterize ground-water flow in Paradise Valley, Nevada, and to evaluate probable long-term effects of five hypothetical development scenarios. One finding of the study is that concentrating pumping at the south end of Paradise Valley may increase underflow from the adjacent Humboldt River valley, and might affect flow in the river.

  5. Assessing the solubility controls on vanadium in groundwater, northeastern San Joaquin Valley, CA

    Science.gov (United States)

    Wright, Michael T.; Stollenwerk, Kenneth G.; Belitz, Kenneth

    2014-01-01

    The solubility controls on vanadium (V) in groundwater were studied due to concerns over possible harmful health effects of ingesting V in drinking water. Vanadium concentrations in the northeastern San Joaquin Valley ranged from 25 μg/L) and lowest in samples collected from anoxic groundwater (70% 2VO4−. Adsorption/desorption reactions with mineral surfaces and associated oxide coatings were indicated as the primary solubility control of V5+ oxyanions in groundwater. Environmental data showed that V concentrations in oxic groundwater generally increased with increasing groundwater pH. However, data from adsorption isotherm experiments indicated that small variations in pH (7.4–8.2) were not likely as an important a factor as the inherent adsorption capacity of oxide assemblages coating the surface of mineral grains. In suboxic groundwater, accurate SM modeling was difficult since Eh measurements of source water were not measured in this study. Vanadium concentrations in suboxic groundwater decreased with increasing pH indicating that V may exist as an oxycationic species [e.g. V(OH)3+]. Vanadium may complex with dissolved inorganic and organic ligands under suboxic conditions, which could alter the adsorption behavior of V in groundwater. Speciation modeling did not predict the existence of V-inorganic ligand complexes and organic ligands were not collected as part of this study. More work is needed to determine processes governing V solubility under suboxic groundwater conditions. Under anoxic groundwater conditions, SM predicts that aqueous V exists as the uncharged V(OH)3 molecule. However, exceedingly low V concentrations show that V is sparingly soluble in anoxic conditions. Results indicated that V may be precipitating as V3+- or mixed V3+/Fe3+-oxides in anoxic groundwater, which is consistent with results of a previous study. The fact that V appears insoluble in anoxic (Fe reducing) redox conditions indicates that the behavior of V is different than

  6. Hydrology and simulation of ground-water flow in Cedar Valley, Iron County, Utah

    Science.gov (United States)

    Brooks, Lynette E.; Mason, James L.

    2005-01-01

    Cedar Valley, located in the eastern part of Iron County in southwestern Utah, is experiencing rapid population growth. Cedar Valley traditionally has supported agriculture, but the growing population needs a larger share of the available water resources. Water withdrawn from the unconsolidated basin fill is the primary source for public supply and is a major source of water for irrigation. Water managers are concerned about increasing demands on the water supply and need hydrologic information to manage this limited water resource and minimize flow of water unsuitable for domestic use toward present and future public-supply sources.Surface water in the study area is derived primarily from snowmelt at higher altitudes east of the study area or from occasional large thunderstorms during the summer. Coal Creek, a perennial stream with an average annual discharge of 24,200 acre-feet per year, is the largest stream in Cedar Valley. Typically, all of the water in Coal Creek is diverted for irrigation during the summer months. All surface water is consumed within the basin by irrigated crops, evapotranspiration, or recharge to the ground-water system.Ground water in Cedar Valley generally moves from primary recharge areas along the eastern margin of the basin where Coal Creek enters, to areas of discharge or subsurface outflow. Recharge to the unconsolidated basin-fill aquifer is by seepage of unconsumed irrigation water, streams, direct precipitation on the unconsolidated basin fill, and subsurface inflow from consolidated rock and Parowan Valley and is estimated to be about 42,000 acre-feet per year. Stable-isotope data indicate that recharge is primarily from winter precipitation. The chloride mass-balance method indicates that recharge may be less than 42,000 acre-feet per year, but is considered a rough approximation because of limited chloride concentration data for precipitation and Coal Creek. Continued declining water levels indicate that recharge is not

  7. Analysis of the Carmel Valley alluvial ground-water basin, Monterey County, California

    Science.gov (United States)

    Kapple, Glenn W.; Mitten, Hugh T.; Durbin, Timothy J.; Johnson, Michael J.

    1984-01-01

    A two-dimensional, finite-element, digital model was developed for the Carmel Valley alluvial ground-water basin using measured, computed, and estimated discharge and recharge data for the basin. Discharge data included evapotranspiration by phreatophytes and agricultural, municipal, and domestic pumpage. Recharge data included river leakage, tributary runoff, and pumping return flow. Recharge from subsurface boundary flow and rainfall infiltration was assumed to be insignificant. From 1974 through 1978, the annual pumping rate ranged from 5,900 to 9,100 acre-feet per year with 55 percent allotted to municipal use principally exported out of the valley, 44 percent to agricultural use, and 1 percent to domestic use. The pumpage return flow within the valley ranged from 900 to 1,500 acre-feet per year. The aquifer properties of transmissivity (about 5,900 feet squared per day) and of the storage coefficient (0.19) were estimated from an average alluvial thickness of 75 feet and from less well-defined data on specific capacity and grain-size distribution. During calibration the values estimated for hydraulic conductivity and storage coefficient for the lower valley were reduced because of the smaller grain size there. The river characteristics were based on field and laboratory analyses of hydraulic conductivity and on altitude survey data. The model is intended principally for simulation of flow conditions using monthly time steps. Time variations in transmissivity and short-term, highrecharge potential are included in the model. The years 1974 through 1978 (including "pre-" and "post-" drought) were selected because of the extreme fluctuation in water levels between the low levels measured during dry years and the above-normal water levels measured during the preceding and following wet years. Also, during this time more hydrologic information was available. Significantly, computed water levels were generally within a few feet of the measured levels, and computed

  8. Groundwater Quality Data for the Northern Sacramento Valley, 2007: Results from the California GAMA Program

    Science.gov (United States)

    Bennett, Peter A.; Bennett, George L.; Belitz, Kenneth

    2009-01-01

    Groundwater quality in the approximately 1,180-square-mile Northern Sacramento Valley study unit (REDSAC) was investigated in October 2007 through January 2008 as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Project was developed in response to the Groundwater Quality Monitoring Act of 2001, and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). The study was designed to provide a spatially unbiased assessment of the quality of raw groundwater used for public water supplies within REDSAC and to facilitate statistically consistent comparisons of groundwater quality throughout California. Samples were collected from 66 wells in Shasta and Tehama Counties. Forty-three of the wells were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study area (grid wells), and 23 were selected to aid in evaluation of specific water-quality issues (understanding wells). The groundwater samples were analyzed for a large number of synthetic organic constituents (volatile organic compounds [VOC], pesticides and pesticide degradates, and pharmaceutical compounds), constituents of special interest (perchlorate and N-nitrosodimethylamine [NDMA]), naturally occurring inorganic constituents (nutrients, major and minor ions, and trace elements), radioactive constituents, and microbial constituents. Naturally occurring isotopes (tritium, and carbon-14, and stable isotopes of nitrogen and oxygen in nitrate, stable isotopes of hydrogen and oxygen of water), and dissolved noble gases also were measured to help identify the sources and ages of the sampled ground water. In total, over 275 constituents and field water-quality indicators were investigated. Three types of quality-control samples (blanks, replicates, and sampmatrix spikes) were collected at approximately 8

  9. Applications of remote sensing, GIS, and groundwater flow modeling in evaluating groundwater resources: Two case studies; East Nile Delta, Egypt and Gold Valley, California, USA

    Science.gov (United States)

    Abdelaziz Ali Ismael, Abdulaziz Mohamed

    jeopardizes a considerable area of the agricultural land with soil salinity and water logging. Therefore, three strategies, each with three scenarios, extending between 2004 and 2024 were designed to involve different pumping stress and infiltration rates from irrigation return to control the rising water level and estimate the production potential of the aquifer during drought. Gold Valley, Death Valley, California, USA. This study evaluates the hydrogeology of Gold Valley as a typical example of intermountain basins of Death Valley area and develops a GIS-based model that reasonably estimates the precipitation infiltration rates from altitude and slope data of the catchment area. Water balance calculations of the hydrological parameters in Gold Valley, provided by Inyo County, California, indicated that the majority of recharge takes place at high altitude (>1100 m) during winter with a negligible effect of evaporation on the stable isotopic composition of groundwater. Furthermore, water balance calculations in Gold Valley were utilized in identifying the coefficients of a GIS-based model that subsequently was refined to the best fit with the calculations of the water budget. A resistivity survey conducted in Gold Valley showed that groundwater is collected in upstream compartmentalized reservoirs and suggests that groundwater flow mostly takes place through the fracture zone of the bedrock. This pattern explains the relationship between precipitational infiltration in the Gold Valley catchment area and the attachment spring flow in Willow Creek. The estimated water budget in Gold Valley and the geoelectric profiles provided from this study can be investigated into the Death Valley Regional Groundwater Flow model (DVRGWF). In addition, the GIS-based model can be efficiently applied in other intermountain basins in Death Valley or other areas of arid environment of the Western U.S. to estimate the local precipitational infiltration. Accurate estimates of flux, well defined

  10. Land subsidence, groundwater levels, and geology in the Coachella Valley, California, 1993-2010

    Science.gov (United States)

    Sneed, Michelle; Brandt, Justin T.; Solt, Mike

    2014-01-01

    Land subsidence associated with groundwater-level declines has been investigated by the U.S. Geological Survey in the Coachella Valley, California, since 1996. Groundwater has been a major source of agricultural, municipal, and domestic supply in the valley since the early 1920s. Pumping of groundwater resulted in water-level declines as much as 15 meters (50 feet) through the late 1940s. In 1949, the importation of Colorado River water to the southern Coachella Valley began, resulting in a reduction in groundwater pumping and a recovery of water levels during the 1950s through the 1970s. Since the late 1970s, demand for water in the valley has exceeded deliveries of imported surface water, resulting in increased pumping and associated groundwater-level declines and, consequently, an increase in the potential for land subsidence caused by aquifer-system compaction. Global Positioning System (GPS) surveying and Interferometric Synthetic Aperture Radar (InSAR) methods were used to determine the location, extent, and magnitude of the vertical land-surface changes in the southern Coachella Valley during 1993–2010. The GPS measurements taken at 11 geodetic monuments in 1996 and in 2010 in the southern Coachella Valley indicated that the elevation of the land surface changed –136 to –23 millimeters (mm) ±54 mm (–0.45 to –0.08 feet (ft) ±0.18 ft) during the 14-year period. Changes at 6 of the 11 monuments exceeded the maximum expected uncertainty of ±54 mm (±0.18 ft) at the 95-percent confidence level, indicating that subsidence occurred at these monuments between June 1996 and August 2010. GPS measurements taken at 17 geodetic monuments in 2005 and 2010 indicated that the elevation of the land surface changed –256 to +16 mm ±28 mm (–0.84 to +0.05 ft ±0.09 ft) during the 5-year period. Changes at 5 of the 17 monuments exceeded the maximum expected uncertainty of ±28 mm (±0.09 ft) at the 95-percent confidence level, indicating that subsidence occurred

  11. Hydrogeologic and geochemical characterization of groundwater resources in Deep Creek Valley and adjacent areas, Juab and Tooele Counties, Utah, and Elko and White Pine Counties, Nevada

    Science.gov (United States)

    Gardner, Philip M.; Masbruch, Melissa D.

    2015-09-18

    The water resources of Deep Creek Valley were assessed during 2012–13 with an emphasis on better understanding the groundwater flow system and groundwater budget. Surface-water resources are limited in Deep Creek Valley and are generally used for agriculture. Groundwater is the predominant water source for most other uses and to supplement irrigation. Most groundwater withdrawal in Deep Creek Valley occurs from the unconsolidated basin-fill deposits, in which conditions are generally unconfined near the mountain front and confined in the lower-altitude parts of the valley. Productive aquifers are also present in fractured bedrock that occurs along the valley margins and beneath the basin-fill deposits. The consolidated-rock and basin-fill aquifers are hydraulically connected in many areas with much of the recharge occurring in the consolidated-rock mountain blocks and most of the discharge occurring from the lower-altitude basin-fill deposits.

  12. Tritium as a tracer for the movement of surface water and groundwater in the Glatt Valley, Switzerland

    International Nuclear Information System (INIS)

    Santschi, P.H.; Hoehn, E.; Lueck, A.; Farrenkothen, K.

    1987-01-01

    A pulse of tritiated water (∼ 500 Ci) accidentally discharged by an isotope processing plant in the Glatt River Valley, northern Switzerland, allowed us to observe the migration of a contaminant pulse through a sewage treatment plant, rivers, and various wells of infiltrated groundwater. The accident pointed to various memory effects of the tritium, which acted as a conservative tracer. Tritium concentrations in surface water and groundwater were used to test predictions for the transport of conservative anthropogenic trace contaminants accidentally discharged into the sewer system. Mass balance calculations indicate that about 2-10% of the tritium pulse infiltrated to the groundwater and about 0.5% of the total reached eight major drinking water wells of this densely populated area. In spite of the complex hydrogeology of the lower Glatt River Valley, tritium breakthrough curves could be effectively simulated with modeling approaches developed from an experimental well field

  13. Evaluation of ground-water quality in the Santa Maria Valley, California

    Science.gov (United States)

    Hughes, Jerry L.

    1977-01-01

    The quality and quantity of recharge to the Santa Maria Valley, Calif., ground-water basin from natural sources, point sources, and agriculture are expressed in terms of a hydrologic budget, a solute balance, and maps showing the distribution of select chemical constituents. Point sources includes a sugar-beet refinery, oil refineries, stockyards, golf courses, poultry farms, solid-waste landfills, and municipal and industrial wastewater-treatment facilities. Pumpage has exceeded recharge by about 10,000 acre-feet per year. The result is a declining potentiometric surface with an accumulation of solutes and an increase in nitrogen in ground water. Nitrogen concentrations have reached as much as 50 milligrams per liter. In comparison to the solutes from irrigation return, natural recharge, and rain, discharge of wastewater from municipal and industrial wastewater-treatment facilities contributes less than 10 percent. The quality of treated wastewater is often lower in select chemical constituents than the receiving water. (Woodard-USGS)

  14. Survey of 218 organic contaminants in groundwater derived from the world's largest untreated wastewater irrigation system: Mezquital Valley, Mexico.

    Science.gov (United States)

    Lesser, Luis E; Mora, Abrahan; Moreau, Cristina; Mahlknecht, Jürgen; Hernández-Antonio, Arturo; Ramírez, Aldo I; Barrios-Piña, Héctor

    2018-05-01

    The Mezquital Valley system is the world's oldest and largest example with regard to use of untreated wastewater for agricultural irrigation. Because of the artificial high recharge associated with the Mezquital Valley aquifers, groundwater is extracted for human consumption, and there are plans to use this groundwater as a water resource for Mexico City. Thus, this study analyzed 218 organic micro-contaminants in wastewater, springs, and groundwater from Mezquital Valley. Five volatile organic compounds (VOCs) and nine semi-volatile organic compounds (SVOCs) were detected in the wastewater used for irrigation. Only two SVOCs [bis-2-(ethylhexyl) phthalate and dibutyl phthalate] were detected in all the wastewater canals and groundwater sources, whereas no VOCs were detected in groundwater and springs. Of the 118 pharmaceutically active compounds (PhACs) and 7 reproductive hormones measured, 65 PhACs and 3 hormones were detected in the wastewater. Of these, metformin, caffeine, and acetaminophen account for almost sixty percent of the total PhACs in wastewater. Nevertheless, 23 PhACs were detected in groundwater sources, where the majority of these compounds have low detection frequencies. The PhACs sulfamethoxazole, N,N-diethyl-meta-toluamide, carbamazepine, and benzoylecgonine (primary cocaine metabolite) were frequently detected in groundwater, suggesting that although the soils act as a filter adsorbing and degrading the majority of the organic pollutant content in wastewater, these PhACs still reach the aquifer. Therefore, the presence of these PhACs, together with the high levels of the endocrine disruptor bis-2-(ethylhexyl) phthalate, indicate that water sources derived from the recharge of the studied aquifers may pose a risk to consumer health. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. Insights into controls on hexavalent chromium in groundwater provided by environmental tracers, Sacramento Valley, California, USA

    Science.gov (United States)

    Manning, Andrew H.; Mills, Christopher T.; Morrison, Jean M.; Ball, Lyndsay B.

    2015-01-01

    Environmental tracers are useful for determining groundwater age and recharge source, yet their application in studies of geogenic Cr(VI) in groundwater has been limited. Environmental tracer data from 166 wells located in the Sacramento Valley, northern California, were interpreted and compared to Cr concentrations to determine the origin and age of groundwater with elevated Cr(VI), and better understand where Cr(VI) becomes mobilized and how it evolves along flowpaths. In addition to major ion and trace element concentrations, the dataset includes δ18O, δ2H, 3H concentration, 14C activity (of dissolved inorganic C), δ13C, 3He/4He ratio, and noble gas concentrations (He, Ne, Ar, Kr, Xe). Noble gas recharge temperatures (NGTs) were computed, and age-related tracers were interpreted in combination to constrain the age distribution in samples and sort them into six different age categories spanning from 10,000 yr old. Nearly all measured Cr is in the form of Cr(IV). Concentrations range from 3 mg L−1), and commonly have δ18O values enriched relative to local precipitation. These samples likely contain irrigation water and are elevated due to accelerated mobilization of Cr(VI) in the unsaturated zone (UZ) in irrigated areas. Group 2 samples are from throughout the valley and typically contain water 1000–10,000 yr old, have δ18O values consistent with local precipitation, and have unexpectedly warm NGTs. Chromium(VI) concentrations in Group 2 samples may be elevated for multiple reasons, but the hypothesis most consistent with all available data (notably, the warm NGTs) is a relatively long UZ residence time due to recharge through a deep UZ near the margin of the basin. A possible explanation for why Cr(VI) may be primarily mobilized in the UZ rather than farther along flowpaths in the oxic portion of the saturated zone is more dynamic cycling of Mn in the UZ due to transient moisture and redox conditions.

  16. An Integrated Hydrologic Model and Remote Sensing Synthesis Approach to Study Groundwater Extraction During a Historic Drought in the California Central Valley

    Science.gov (United States)

    Thatch, L. M.; Maxwell, R. M.; Gilbert, J. M.

    2017-12-01

    Over the past century, groundwater levels in California's San Joaquin Valley have dropped more than 30 meters in some areas due to excessive groundwater extraction to irrigate agricultural lands and feed a growing population. Between 2012 and 2016 California experienced the worst drought in its recorded history, further exacerbating this groundwater depletion. Due to lack of groundwater regulation, exact quantities of extracted groundwater in California are unknown and hard to quantify. We use a synthesis of integrated hydrologic model simulations and remote sensing products to quantify the impact of drought and groundwater pumping on the Central Valley water tables. The Parflow-CLM model was used to evaluate groundwater depletion in the San Joaquin River basin under multiple groundwater extraction scenarios simulated from pre-drought through recent drought years. Extraction scenarios included pre-development conditions, with no groundwater pumping; historical conditions based on decreasing groundwater level measurements; and estimated groundwater extraction rates calculated from the deficit between the predicted crop water demand, based on county land use surveys, and available surface water supplies. Results were compared to NASA's Gravity Recover and Climate Experiment (GRACE) data products to constrain water table decline from groundwater extraction during severe drought. This approach untangles various factors leading to groundwater depletion within the San Joaquin Valley both during drought and years of normal recharge to help evaluate which areas are most susceptible to groundwater overdraft, as well as further evaluating the spatially and temporally variable sustainable yield. Recent efforts to improve water management and ensure reliable water supplies are highlighted by California's Sustainable Groundwater Management Act (SGMA) which mandates Groundwater Sustainability Agencies to determine the maximum quantity of groundwater that can be withdrawn through

  17. Stream seepage and groundwater levels, Wood River Valley, south-central Idaho, 2012-13

    Science.gov (United States)

    Bartolino, James R.

    2014-01-01

    Stream discharge and water levels in wells were measured at multiple sites in the Wood River Valley, south-central Idaho, in August 2012, October 2012, and March 2013, as a component of data collection for a groundwater-flow model of the Wood River Valley aquifer system. This model is a cooperative and collaborative effort between the U.S. Geological Survey and the Idaho Department of Water Resources. Stream-discharge measurements for determination of seepage were made during several days on three occasions: August 27–28, 2012, October 22–24, 2012, and March 27–28, 2013. Discharge measurements were made at 49 sites in August and October, and 51 sites in March, on the Big Wood River, Silver Creek, their tributaries, and nearby canals. The Big Wood River generally gains flow between the Big Wood River near Ketchum streamgage (13135500) and the Big Wood River at Hailey streamgage (13139510), and loses flow between the Hailey streamgage and the Big Wood River at Stanton Crossing near Bellevue streamgage (13140800). Shorter reaches within these segments may differ in the direction or magnitude of seepage or may be indeterminate because of measurement uncertainty. Additional reaches were measured on Silver Creek, the North Fork Big Wood River, Warm Springs Creek, Trail Creek, and the East Fork Big Wood River. Discharge measurements also were made on the Hiawatha, Cove, District 45, Glendale, and Bypass Canals, and smaller tributaries to the Big Wood River and Silver Creek. Water levels in 93 wells completed in the Wood River Valley aquifer system were measured during October 22–24, 2012; these wells are part of a network established by the U.S. Geological Survey in 2006. Maps of the October 2012 water-table altitude in the unconfined aquifer and the potentiometric-surface altitude of the confined aquifer have similar topology to those on maps of October 2006 conditions. Between October 2006 and October 2012, water-table altitude in the unconfined aquifer rose by

  18. Prediction and visualization of redox conditions in the groundwater of Central Valley, California

    Science.gov (United States)

    Rosecrans, Celia Z.; Nolan, Bernard T.; Gronberg, JoAnn M.

    2017-03-01

    Regional-scale, three-dimensional continuous probability models, were constructed for aspects of redox conditions in the groundwater system of the Central Valley, California. These models yield grids depicting the probability that groundwater in a particular location will have dissolved oxygen (DO) concentrations less than selected threshold values representing anoxic groundwater conditions, or will have dissolved manganese (Mn) concentrations greater than selected threshold values representing secondary drinking water-quality contaminant levels (SMCL) and health-based screening levels (HBSL). The probability models were constrained by the alluvial boundary of the Central Valley to a depth of approximately 300 m. Probability distribution grids can be extracted from the 3-D models at any desired depth, and are of interest to water-resource managers, water-quality researchers, and groundwater modelers concerned with the occurrence of natural and anthropogenic contaminants related to anoxic conditions. Models were constructed using a Boosted Regression Trees (BRT) machine learning technique that produces many trees as part of an additive model and has the ability to handle many variables, automatically incorporate interactions, and is resistant to collinearity. Machine learning methods for statistical prediction are becoming increasing popular in that they do not require assumptions associated with traditional hypothesis testing. Models were constructed using measured dissolved oxygen and manganese concentrations sampled from 2767 wells within the alluvial boundary of the Central Valley, and over 60 explanatory variables representing regional-scale soil properties, soil chemistry, land use, aquifer textures, and aquifer hydrologic properties. Models were trained on a USGS dataset of 932 wells, and evaluated on an independent hold-out dataset of 1835 wells from the California Division of Drinking Water. We used cross-validation to assess the predictive performance of

  19. Baseline risk assessment for groundwater contamination at the uranium mill tailings site near Monument Valley, Arizona. Draft

    Energy Technology Data Exchange (ETDEWEB)

    1993-09-01

    This baseline risk assessment evaluates potential impact to public health or the environment resulting from groundwater contamination at the former uranium mill processing site near Monument Valley, Arizona. The tailings and other contaminated material at this site are being relocated and stabilized in a disposal cell at Mexican Hat, Utah, through the US Department of Energy (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. The tailings removal is planned for completion by spring 1994. After the tailings are removed, groundwater contamination at the site will continue to be evaluated. This risk assessment is the first document specific to this site for the Groundwater Project. It will be used to assist in determining what remedial action is needed for contaminated groundwater at the site.

  20. Potential effects of existing and proposed groundwater withdrawals on water levels and natural groundwater discharge in Snake Valley and surrounding areas, Utah and Nevada

    Science.gov (United States)

    Masbruch, Melissa D.; Brooks, Lynette E.

    2017-04-14

    Several U.S. Department of Interior (DOI) agencies are concerned about the cumulative effects of groundwater development on groundwater resources managed by, and other groundwater resources of interest to, these agencies in Snake Valley and surrounding areas. The new water uses that potentially concern the DOI agencies include 12 water-right applications filed in 2005, totaling approximately 8,864 acre-feet per year. To date, only one of these applications has been approved and partially developed. In addition, the DOI agencies are interested in the potential effects of three new water-right applications (UT 18-756, UT 18-758, and UT 18-759) and one water-right change application (UT a40687), which were the subject of a water-right hearing on April 19, 2016.This report presents a hydrogeologic analysis of areas in and around Snake Valley to assess potential effects of existing and future groundwater development on groundwater resources, specifically groundwater discharge sites, of interest to the DOI agencies. A previously developed steady-state numerical groundwater-flow model was modified to transient conditions with respect to well withdrawals and used to quantify drawdown and capture (withdrawals that result in depletion) of natural discharge from existing and proposed groundwater withdrawals. The original steady-state model simulates and was calibrated to 2009 conditions. To investigate the potential effects of existing and proposed groundwater withdrawals on the groundwater resources of interest to the DOI agencies, 10 withdrawal scenarios were simulated. All scenarios were simulated for periods of 5, 10, 15, 30, 55, and 105 years from the start of 2010; additionally, all scenarios were simulated to a new steady state to determine the ultimate long-term effects of the withdrawals. Capture maps were also constructed as part of this analysis. The simulations used to develop the capture maps test the response of the system, specifically the reduction of natural

  1. Modeling groundwater/surface-water interactions in an Alpine valley (the Aosta Plain, NW Italy): the effect of groundwater abstraction on surface-water resources

    Science.gov (United States)

    Stefania, Gennaro A.; Rotiroti, Marco; Fumagalli, Letizia; Simonetto, Fulvio; Capodaglio, Pietro; Zanotti, Chiara; Bonomi, Tullia

    2018-02-01

    A groundwater flow model of the Alpine valley aquifer in the Aosta Plain (NW Italy) showed that well pumping can induce river streamflow depletions as a function of well location. Analysis of the water budget showed that ˜80% of the water pumped during 2 years by a selected well in the downstream area comes from the baseflow of the main river discharge. Alluvial aquifers hosted in Alpine valleys fall within a particular hydrogeological context where groundwater/surface-water relationships change from upstream to downstream as well as seasonally. A transient groundwater model using MODFLOW2005 and the Streamflow-Routing (SFR2) Package is here presented, aimed at investigating water exchanges between the main regional river (Dora Baltea River, a left-hand tributary of the Po River), its tributaries and the underlying shallow aquifer, which is affected by seasonal oscillations. The three-dimensional distribution of the hydraulic conductivity of the aquifer was obtained by means of a specific coding system within the database TANGRAM. Both head and flux targets were used to perform the model calibration using PEST. Results showed that the fluctuations of the water table play an important role in groundwater/surface-water interconnections. In upstream areas, groundwater is recharged by water leaking through the riverbed and the well abstraction component of the water budget changes as a function of the hydraulic conditions of the aquifer. In downstream areas, groundwater is drained by the river and most of the water pumped by wells comes from the base flow component of the river discharge.

  2. Geology and ground-water resources of the Ahtanum Valley, Yakima County, Washington

    Science.gov (United States)

    Foxworthy, B.L.

    1962-01-01

    The Ahtanum Valley covers an area of about 100 square miles in an important agricultural district in central Yakima County, Wash. Because the area is semiarid, virtually all crops require irrigation. Surface-water supplies are inadequate in most of the area, and ground water is being used increasingly for irrigation. The purpose of this investigation was the collection and interpretation of data, pertaining to ground water in the area as an aid in the proper development and management of the water resources. The occurrence and movement of ground water in the Ahtanum Valley are directly related to the geology. The valley occupies part of a structural trough (Ahtanum-Moxee subbasin) that is underlain by strongly folded flow layers of a thick sequence of the Yakima basalt. The upper part of the basalt sequence interfingers with, and is conformably overlying by, sedimentary rocks of the Ellensburg formation which are as much as 1,000 feet thick. These rocks are in turn overlying unconformably by cemented basalt gravel as much as 400 feet thick. Unconsolidated alluvial sand and gravel, as much as 30 feet thick, form the valley floor. Although ground water occurs in each of the rock units within the area, the Yakima basalt and the unconsolidated alluvium yield about three-fourths of the ground water currently used. Wells in the area range in depth from a few feet to more than 1,200 feet and yield from less than 1 to more than 1,030 gallons per minute. Although water levels in water-table wells usually are shallow--often less than 5 feet below the land surface--levels in deeper wells tapping confined water range from somewhat above the land surface (in flowing wells) to about 200 feet below. Wells drilled into aquifers in the Yakima basalt, the Ellensburg formation, and the cemented gravel usually tap confined water, and at least 12 wells in the area flow or have flowed in the past. Ground-water levels fluctuate principally in response to changes in stream levels

  3. Data Validation Package, December 2015, Groundwater and Surface Water Sampling at the Monument Valley, Arizona, Processing Site March 2016

    Energy Technology Data Exchange (ETDEWEB)

    Tyrrell, Evan [Navarro Research and Engineering, Inc., Oak Ridge, NV (United States); Denny, Angelita [USDOE Office of Legacy Management, Washington, DC (United States)

    2016-03-23

    Fifty-two groundwater samples and one surface water sample were collected at the Monument Valley, Arizona, Processing Site to monitor groundwater contaminants for evaluating the effectiveness of the proposed compliance strategy as specified in the 1999 Final Site Observational Work Plan for the UMTRA Project Site at Monument Valley, Arizona. Sampling and analyses were conducted as specified in the Sampling and Analysis Plan for U.S. Department of Energy Office of Legacy Management Sites (LMS/PRO/S04351, continually updated, http://energy.gov/lm/downloads/sampling-and-analysis-plan-us-department- energy-office-legacy-management-sites). Samples were collected for metals, anions, nitrate + nitrite as N, and ammonia as N analyses at all locations.

  4. A statistical learning framework for groundwater nitrate models of the Central Valley, California, USA

    Science.gov (United States)

    Nolan, Bernard T.; Fienen, Michael N.; Lorenz, David L.

    2015-01-01

    We used a statistical learning framework to evaluate the ability of three machine-learning methods to predict nitrate concentration in shallow groundwater of the Central Valley, California: boosted regression trees (BRT), artificial neural networks (ANN), and Bayesian networks (BN). Machine learning methods can learn complex patterns in the data but because of overfitting may not generalize well to new data. The statistical learning framework involves cross-validation (CV) training and testing data and a separate hold-out data set for model evaluation, with the goal of optimizing predictive performance by controlling for model overfit. The order of prediction performance according to both CV testing R2 and that for the hold-out data set was BRT > BN > ANN. For each method we identified two models based on CV testing results: that with maximum testing R2 and a version with R2 within one standard error of the maximum (the 1SE model). The former yielded CV training R2 values of 0.94–1.0. Cross-validation testing R2 values indicate predictive performance, and these were 0.22–0.39 for the maximum R2 models and 0.19–0.36 for the 1SE models. Evaluation with hold-out data suggested that the 1SE BRT and ANN models predicted better for an independent data set compared with the maximum R2 versions, which is relevant to extrapolation by mapping. Scatterplots of predicted vs. observed hold-out data obtained for final models helped identify prediction bias, which was fairly pronounced for ANN and BN. Lastly, the models were compared with multiple linear regression (MLR) and a previous random forest regression (RFR) model. Whereas BRT results were comparable to RFR, MLR had low hold-out R2 (0.07) and explained less than half the variation in the training data. Spatial patterns of predictions by the final, 1SE BRT model agreed reasonably well with previously observed patterns of nitrate occurrence in groundwater of the Central Valley.

  5. Simulation of recharge for the Death Valley regional groundwater flow system using an integrated hydrologic model

    Science.gov (United States)

    Hevesi, J. A.; Regan, R. S.; Hill, M. C.; Heywood, C.; Kohn, M. S.

    2012-12-01

    A proof-of-concept study was conducted using the integrated hydrologic model, GSFLOW, to simulate spatially and temporally distributed recharge for the Death Valley regional groundwater flow system (DVRFS). GSFLOW is an integrated groundwater - surface water flow model that combines two modeling applications: the Precipitation-Runoff-Modeling-System (PRMS) and MODFLOW. Previous methods used to estimate recharge for the DVRFS include empirical models based on precipitation, applications of the chloride mass-balance method, and applications of a precipitation-runoff model, INFIL, which used a daily time step to simulate recharge as net infiltration through the root zone. The GSFLOW model offers several potential advantages compared to the previous methods including (1) the ability to simulate complex flow through a thick unsaturated zone (UZ), allowing for the dampening and time delay of recharge relative to the infiltration signal at the top of the UZ and also allowing for the redistribution of flow within the UZ, as enabled by the MODFLOW-NWT and UZF capabilities, (2) the simulation of rejected recharge in response to the dynamics of groundwater discharge and low permeability zones in the UZ, (3) a more explicit representation of streamflow and recharge processes in the mostly ephemeral stream channels that characterize the DVRFS, and (4) the ability to simulate complex flow paths for runoff occurring as both overland flow and shallow subsurface flow (interflow) in the soil zone using a network of cascades connecting hydrologic response units (HRUs). Simulations were done using a daily time step for water years 1980-2010. Preliminary estimates of recharge using GSFLOW indicate that the distribution of recharge is highly variable both spatially and temporally due to variability in precipitation, snowmelt, evapotranspiration, runoff, and the permeability of bedrock and alluvium underlying the root zone. Results averaged over the areas of subbasins were similar to

  6. Drought resilience of the California Central Valley surface-groundwater-conveyance system

    Energy Technology Data Exchange (ETDEWEB)

    Miller, N.L.; Dale, L.L.; Brush, C.; Vicuna, S.; Kadir, T.N.; Dogrul, E.C.; Chung, F.I.

    2009-05-15

    A series of drought simulations were performed for the California Central Valley using computer applications developed by the California Department of Water Resources and historical datasets representing a range of droughts from mild to severe for time periods lasting up to 60 years. Land use, agricultural cropping patterns, and water demand were held fixed at the 2003 level and water supply was decreased by amounts ranging between 25 and 50%, representing light to severe drought types. Impacts were examined for four hydrologic subbasins, the Sacramento Basin, the San Joaquin Basin, the Tulare Basin, and the Eastside Drainage. Results suggest the greatest impacts are in the San Joaquin and Tulare Basins, regions that are heavily irrigated and are presently overdrafted in most years. Regional surface water diversions decrease by as much as 70%. Stream-to-aquifer flows and aquifer storage declines were proportional to drought severity. Most significant was the decline in ground water head for the severe drought cases, where results suggest that under these scenarios the water table is unlikely to recover within the 30-year model-simulated future. However, the overall response to such droughts is not as severe as anticipated and the Sacramento Basin may act as ground-water insurance to sustain California during extended dry periods.

  7. Quality of groundwater and surface water, Wood River Valley, south-central Idaho, July and August 2012

    Science.gov (United States)

    Hopkins, Candice B.; Bartolino, James R.

    2013-01-01

    Residents and resource managers of the Wood River Valley of south-central Idaho are concerned about the effects that population growth might have on the quality of groundwater and surface water. As part of a multi-phase assessment of the groundwater resources in the study area, the U.S. Geological Survey evaluated the quality of water at 45 groundwater and 5 surface-water sites throughout the Wood River Valley during July and August 2012. Water samples were analyzed for field parameters (temperature, pH, specific conductance, dissolved oxygen, and alkalinity), major ions, boron, iron, manganese, nutrients, and Escherichia coli (E.coli) and total coliform bacteria. This study was conducted to determine baseline water quality throughout the Wood River Valley, with special emphasis on nutrient concentrations. Water quality in most samples collected did not exceed U.S. Environmental Protection Agency standards for drinking water. E. coli bacteria, used as indicators of water quality, were detected in all five surface-water samples and in two groundwater samples collected. Some analytes have aesthetic-based recommended drinking water standards; one groundwater sample exceeded recommended iron concentrations. Nitrate plus nitrite concentrations varied, but tended to be higher near population centers and in agricultural areas than in tributaries and less populated areas. These higher nitrate plus nitrite concentrations were not correlated with boron concentrations or the presence of bacteria, common indicators of sources of nutrients to water. None of the samples collected exceeded drinking-water standards for nitrate or nitrite. The concentration of total dissolved solids varied considerably in the waters sampled; however a calcium-magnesium-bicarbonate water type was dominant (43 out of 50 samples) in both the groundwater and surface water. Three constituents that may be influenced by anthropogenic activity (chloride, boron, and nitrate plus nitrite) deviate from this

  8. Valley formation by groundwater seepage, pressurized groundwater outbursts and crater-lake overflow in flume experiments with implications for Mars

    NARCIS (Netherlands)

    Marra, Wouter A.; Braat, Lisanne; Baar, Anne W.; Kleinhans, Maarten G.

    2014-01-01

    Remains of fluvial valleys on Mars reveal the former presence of water on the surface. However, the source of water and the hydrological setting is not always clear, especially in types of valleys that are rare on Earth and where we have limited knowledge of the processes involved. We investigated

  9. Detection of Waterborne Protozoa, Viruses, and Bacteria in Groundwater and Other Water Samples in the Kathmandu Valley, Nepal

    Science.gov (United States)

    Haramoto, E.

    2018-03-01

    In this study, the prevalence of various waterborne pathogens in water samples collected in the Kathmandu Valley, Nepal, and the applicability of Escherichia coli as an indicator of pathogen contamination in groundwater were assessed. Fifty-three water samples, including shallow groundwater and river water, were analyzed to examine the presence of protozoan (oo)cysts via fluorescence microscopy and that of viral and bacterial genomes via quantitative PCR. At least one of the seven types of pathogens tested (i.e., Cryptosporidium, Giardia, human adenoviruses, noroviruses of genogroups I and II, group A rotaviruses, and Vibrio cholerae) was detected in 68% (15/22) of the shallow dug well water samples; groundwater in the shallow dug wells was more contaminated compared with that in shallow tube wells (8/15, 53%). River water and sewage samples were contaminated with extremely high concentrations of multiple pathogens, whereas a tap water sample supplied by a water tanker tested positive for human adenoviruses and V. cholerae. The detection of host-specific Bacteroidales genetic markers revealed the effects of human and animal feces on groundwater contamination. The tested pathogens were sometimes detected even in E. coli-negative groundwater samples, indicative of the limitations of using E. coli as an indicator for waterborne pathogens in groundwater.

  10. Hydrochemistry of the Mahomet Bedrock Valley Aquifer, East-Central Illinois: indicators of recharge and ground-water flow

    Science.gov (United States)

    Panno, S.V.; Hackley, Keith C.; Cartwright, K.; Liu, Chao-Li

    1994-01-01

    A conceptual model of the ground-water flow and recharge to the Mahomet Bedrock Valley Aquifer (MVA), east-central Illinois, was developed using major ion chemistry and isotope geochemistry. The MVA is a 'basal' fill in the east-west trending buried bedrock valley composed of clean, permeable sand and gravel to thicknesses of up to 61 m. It is covered by a thick sequence of glacial till containing thinner bodies of interbedded sand and gravel. Ground water from the MVA was found to be characterized by clearly defined geochemical regions with three distinct ground-water types. A fourth ground-water type was found at the confluence of the MVA and the Mackinaw Bedrock Valley Aquifer (MAK) to the west. Ground water in the Onarga Valley, a northeastern tributary of the MVA, is of two types, a mixed cation-SO42- type and a mixed cation-HCO3- type. The ground water is enriched in Na+, Ca2+, Mg2+, and SO42- which appears to be the result of an upward hydraulic gradient and interaction of deeper ground water with oxidized pyritic coals and shale. We suggest that recharge to the Onarga Valley and overlying aquifers is 100% from bedrock (leakage) and lateral flow from the MVA to the south. The central MVA (south of the Onarga Valley) is composed of relatively dilute ground water of a mixed cation-HCO3- type, with low total dissolved solids, and very low concentrations of Cl- and SO42-. Stratigraphic relationships of overlying aquifers and ground-water chemistry of these and the MVA suggest recharge to this region of the MVA (predominantly in Champaign County) is relatively rapid and primarily from the surface. Midway along the westerly flow path of the MVA (western MVA), ground water is a mixed cation-HCO3- type with relatively high Cl-, where Cl- increases abruptly by one to ??? two orders of magnitude. Data suggest that the increase in Cl- is the result of leakage of saline ground water from bedrock into the MVA. Mass-balance calculations indicate that approximately 9.5% of

  11. Ground-water flow and recharge in the Mahomet Bedrock Valley Aquifer, east-central Illinois: A conceptual model based on hydrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Panno, S.V.; Hackley, K.C.; Cartwright, K.; Liu, C.L. (Illinois State Geological Survey, Champaign, IL (United States))

    1994-04-01

    Major-ion and isotopic analyses of ground water have been used to develop a conceptual model of flow and recharge to the Mahomet Bedrock Valley Aquifer (MVA). The MVA is composed of clean, permeable sands and gravels and forms a basal'' fill up to 60 m thick in a buried, west-trending bedrock valley. A thick succession of glacial tills, some containing interbedded lenses of sand and gravel, covers the MVA. Three regions within the MVA have hydrochemically distinct ground-water types. A fourth ground-water type was found at the confluence of the MVA and the Mackinaw Bedrock Valley Aquifer (MAK) to the west.

  12. Hydrogeology of, and simulation of ground-water flow in a mantled carbonate-rock system, Cumberland Valley, Pennsylvania

    Science.gov (United States)

    Chichester, D.C.

    1996-01-01

    The U.S. Geological Survey conducted a study in a highly productive and complex regolith-mantled carbonate valley in the northeastern part of the Cumberland Valley, Pa., as part of its Appalachian Valleys and Piedmont Regional Aquifer-system Analysis program. The study was designed to quantify the hydrogeologic characteristics and understand the ground-water flow system of a highly productive and complex thickly mantled carbonate valley. The Cumberland Valley is characterized by complexly folded and faulted carbonate bedrock in the valley bottom, by shale and graywacke to the north, and by red-sedimentary and diabase rocks in the east-southeast. Near the southern valley hillslope, the carbonate rock is overlain by wedge-shaped deposit of regolith, up to 450 feet thick, that is composed of residual material, alluvium, and colluvium. Locally, saturated regolith is greater than 200 feet thick. Seepage-run data indicate that stream reaches, near valley walls, are losing water from the stream, through the regolith, to the ground-water system. Results of hydrograph-separation analyses indicate that base flow in stream basins dominated by regolith-mantled carbonate rock, carbonate rock, and carbonate rock and shale are 81.6, 93.0, and 67.7 percent of total streamflow, respectively. The relative high percentage for the regolith-mantled carbonate-rock basin indicates that the regolith stores precipitation and slowly, steadily releases this water to the carbonate-rock aquifer and to streams as base flow. Anomalies in water-table gradients and configuration are a result of topography and differences in the character and distribution of overburden material, permeability, rock type, and geologic structure. Most ground-water flow is local, and ground water discharges to nearby springs and streams. Regional flow is northeastward to the Susquehanna River. Average-annual water budgets were calculated for the period of record from two continuous streamflow-gaging stations. Average

  13. The geochemistry of Don Juan Pond: Evidence for a deep groundwater flow system in Wright Valley, Antarctica

    Science.gov (United States)

    Toner, J. D.; Catling, D. C.; Sletten, R. S.

    2017-09-01

    Don Juan Pond (DJP), Antarctica, is one of the most unusual surface waters on Earth because of its CaCl2-rich composition. To investigate the evolution of pond waters during closed-basin evaporation and to understand the source of brines responsible for the chemistry of DJP, we apply a newly developed low-temperature aqueous model in the Na-K-Ca-Mg-Cl system to DJP. By modeling the closed-basin evaporation of DJP and comparing ionic ratios between DJP surface water, deep groundwater, shallow groundwater, and other surface chemistries in Wright Valley, we find that DJP is best explained by upwelling deep groundwater, as opposed to recent hypotheses proposing shallow groundwater sources. The early closed-basin evolution of brines in our model accurately predicts observed chemistries in DJP; however, late-stage closed-basin evaporation produces Mg-K-rich brines and salts that do not match the CaCl2-rich brine in DJP. Based on groundwater inflow rates to DJP, we estimate that even the most concentrated brines in DJP have undergone closed-basin evaporation for less than a year. To explain the observed lack of Mg2+ and K+ accumulation in DJP over time, and the surprisingly young age for the brines, we deduce that DJP is a localized upwelling from a regional groundwater flow-through system in which evaporated DJP brines are recycled back into the subsurface over yearly timescales. The existence of a regional groundwater flow system beneath DJP has implications for water and solute budgets in cold desert ecosystems, and may provide clues for the formation of groundwater and aqueous flows on Mars.

  14. Factors affecting groundwater quality in the Valley and Ridge aquifers, eastern United States, 1993-2002

    Science.gov (United States)

    Johnson, Gregory C.; Zimmerman, Tammy M.; Lindsey, Bruce D.; Gross, Eliza L.

    2011-01-01

    Chemical and microbiological analyses of water from 230 wells and 35 springs in the Valley and Ridge Physiographic Province, sampled between 1993 and 2002, indicated that bedrock type (carbonate or siliciclastic rock) and land use were dominant factors influencing groundwater quality across a region extending from northwestern Georgia to New Jersey. The analyses included naturally occurring compounds (major mineral ions and radon) and anthropogenic contaminants [pesticides and volatile organic compounds (VOCs)], and contaminants, such as nitrate and bacteria, which commonly increase as a result of human activities. Natural factors, such as topographic position and the mineral composition of underlying geology, act to produce basic physical and geochemical conditions in groundwater that are reflected in physical properties, such as pH, temperature, specific conductance, and alkalinity, and in chemical concentrations of dissolved oxygen, radon, and major mineral ions. Anthropogenic contaminants were most commonly found in water from wells and springs in carbonate-rock aquifers. Nitrate concentrations exceeded U.S. Environmental Protection Agency maximum contaminant levels in 12 percent of samples, most of which were from carbonate-rock aquifers. Escherichia coli (E. coli), pesticide, and VOC detection frequencies were significantly higher in samples from sites in carbonate-rock aquifers. Naturally occurring elements, such as radon, iron, and manganese, were found in higher concentrations in siliciclastic-rock aquifers. Radon levels exceeded the proposed maximum contaminant level of 300 picocuries per liter in 74 percent of the samples, which were evenly distributed between carbonate- and siliciclastic-rock aquifers. The land use in areas surrounding wells and springs was another significant explanatory variable for the occurrence of anthropogenic compounds. Nitrate and pesticide concentrations were highest in samples collected from sites in agricultural areas and

  15. Hydrogeologic evaluation and numerical simulation of the Death Valley regional ground-water flow system, Nevada and California

    International Nuclear Information System (INIS)

    D'Agnese, F.A.; Faunt, C.C.; Turner, A.K.; Hill, M.C.

    1997-01-01

    Yucca Mountain is being studied as a potential site for a high-level radioactive waste repository. In cooperation with the U.S. Department of Energy, the U.S. Geological Survey is evaluating the geologic and hydrologic characteristics of the ground-water system. The study area covers approximately 100,000 square kilometers between lat 35 degrees N., long 115 degrees W and lat 38 degrees N., long 118 degrees W and encompasses the Death Valley regional ground-water flow system. Hydrology in the region is a result of both the and climatic conditions and the complex described as dominated by interbasinal flow and may be conceptualized as having two main components: a series of relatively shallow and localized flow paths that are superimposed on deeper regional flow paths. A significant component of the regional ground-water flow is through a thick Paleozoic carbonate rock sequence. Throughout the regional flow system, ground-water flow is probably controlled by extensive and prevalent structural features that result from regional faulting and fracturing. Hydrogeologic investigations over a large and hydrogeologically complex area impose severe demands on data management. This study utilized geographic information systems and geoscientific information systems to develop, store, manipulate, and analyze regional hydrogeologic data sets describing various components of the ground-water flow system

  16. Hydrogeologic evaluation and numerical simulation of the Death Valley regional ground-water flow system, Nevada and California

    Energy Technology Data Exchange (ETDEWEB)

    D`Agnese, F.A.; Faunt, C.C.; Turner, A.K.; Hill, M.C.

    1997-12-31

    Yucca Mountain is being studied as a potential site for a high-level radioactive waste repository. In cooperation with the U.S. Department of Energy, the U.S. Geological Survey is evaluating the geologic and hydrologic characteristics of the ground-water system. The study area covers approximately 100,000 square kilometers between lat 35{degrees}N., long 115{degrees}W and lat 38{degrees}N., long 118{degrees}W and encompasses the Death Valley regional ground-water flow system. Hydrology in the region is a result of both the and climatic conditions and the complex described as dominated by interbasinal flow and may be conceptualized as having two main components: a series of relatively shallow and localized flow paths that are superimposed on deeper regional flow paths. A significant component of the regional ground-water flow is through a thick Paleozoic carbonate rock sequence. Throughout the regional flow system, ground-water flow is probably controlled by extensive and prevalent structural features that result from regional faulting and fracturing. Hydrogeologic investigations over a large and hydrogeologically complex area impose severe demands on data management. This study utilized geographic information systems and geoscientific information systems to develop, store, manipulate, and analyze regional hydrogeologic data sets describing various components of the ground-water flow system.

  17. Status and understanding of groundwater quality in the Santa Clara River Valley, 2007-California GAMA Priority Basin Project

    Science.gov (United States)

    Burton, Carmen A.; Montrella, Joseph; Landon, Matthew K.; Belitz, Kenneth

    2011-01-01

    Groundwater quality in the approximately 460-square-mile Santa Clara River Valley study unit was investigated from April through June 2007 as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Project is conducted by the U.S. Geological Survey (USGS) in collaboration with the California State Water Resources Control Board and the Lawrence Livermore National Laboratory. The Santa Clara River Valley study unit contains eight groundwater basins located in Ventura and Los Angeles Counties and is within the Transverse and Selected Peninsular Ranges hydrogeologic province. The Santa Clara River Valley study unit was designed to provide a spatially unbiased assessment of the quality of untreated (raw) groundwater in the primary aquifer system. The assessment is based on water-quality and ancillary data collected in 2007 by the USGS from 42 wells on a spatially distributed grid, and on water-quality data from the California Department of Public Health (CDPH) database. The primary aquifer system was defined as that part of the aquifer system corresponding to the perforation intervals of wells listed in the CDPH database for the Santa Clara River Valley study unit. The quality of groundwater in the primary aquifer system may differ from that in shallow or deep water-bearing zones; for example, shallow groundwater may be more vulnerable to surficial contamination. Eleven additional wells were sampled by the USGS to improve understanding of factors affecting water quality.The status assessment of the quality of the groundwater used data from samples analyzed for anthropogenic constituents, such as volatile organic compounds (VOCs) and pesticides, as well as naturally occurring inorganic constituents, such as major ions and trace elements. The status assessment is intended to characterize the quality of untreated groundwater resources in the primary aquifers of the Santa Clara River Valley study unit

  18. Transport of contaminants during storms in the White Oak Creek and Melton Branch watersheds

    International Nuclear Information System (INIS)

    Solomon, D.K.; Marsh, J.D.; Larsen, I.L.; Wickliff, D.S.; Clapp, R.B.

    1991-01-01

    This report documents the transport of contaminants from Solid Waste Storage Area (SWSA) 5 along two principle pathways: the saturated groundwater system and the intermittently saturated storm flow system. The results of the storm flow sampling show a 90 Sr anomaly in SWSA 5 that is suggested by the similar mobility of 3 H and 90 Sr, in spite of the reactive nature of 90 Sr. An empirical relationship between concentration and discharge was established for 3 H and 90 Sr in the Melton Branch Watershed. The relationship is of the form C = AD b , where C is concentration of either 3 H or 90 Sr, D is discharge at MBS, and A and b are empirical constants. A model was developed and a computer program written to separate the discharge into quick-flow and base flow components. The results of the modeling, using data collected during storm flow, showed that 44% of the annual stream discharge occurred as quick flow, whereas only 16% of the 3 H and 27% of the 90 Sr occurred as quick flow. The data show that for SWSA 5 the saturated groundwater pathway is quite important in dry years, such as the 1988 water year. Data from other areas, such as SWSA 6 suggest that the storm flow pathway may be more important in wet years. This study has several important implications for remedial actions and site monitoring. 23 refs., 52 figs., 2 tabs

  19. Tracing deep sources of groundwater salinisation in the Dead Sea Rift Valley a stable isotope and Rare Earth Element approach

    Science.gov (United States)

    Geyer, S.; Möller, P.; Siebert, C.

    2003-04-01

    Salinisation of fresh groundwater reservoirs is a widespread problem, especially in arid regions. As a first step for protection it is crucial to identify its sources and mechanisms. The Jordan Rift Valley between Israel and Jordan is the deepest land depression on earth with the Dead Sea with -410 m below sea level, functioning as a receiving reservoir for the surrounding highlands. Groundwater quality changes drastically within sharp boundaries indicating an admixture of saline groundwater components of different origins. For example Lake Kinneret (Sea of Galilee), situated in the northern part of the Jordan Rift Graben, serves as an important drinking water reservoir for Israel and by treaty also for Jordan. The water quality is affected by an influx of saline groundwater by salty springs located at the lake shore but also within the lake and by an up welling seepage via the lake floor. More or less two main groups of theories exist about the primary origin of the salinity. One is that the salinisation derives by dilution of an ancient, intensively evaporated brine developed in a lake formed in the Rift Valley following seawater intrusion during late Miocene [1]. The other is that the salinisation derives from dissolved evaporative sediments in a depth of 2000 meters or more. The existence of these sediments is not proven but strong hints exists [2]. Based on isotope and chemical data at least three different water types can be distinguished which all can be explained by mixing of more or less one original brine with recent young groundwater. Literature [1]Bergelson et al. (1999): Salinization and dilution history of ground water discharging into the Sea of Galilee, The Dead Sea Transform, Israel.-- Appl. Geochem. 14: 91--118. [2] Flexer et al. (2000): A Neogene salt body as the primary source of salinity in Lake Kinneret.-- Arch. Hydrobiol. Spec. Issues Advanc. Limnol. 55: 69--85.

  20. Ground-water quality and geochemistry in Dayton, Stagecoach, and Churchill Valleys, western Nevada

    Science.gov (United States)

    Thomas, James M.; Lawrence, Stephen J.

    1994-01-01

    The U.S. Geological Survey investigated the quality of ground water in the Dayton, Stagecoach, and Churchill Valleys as part of the Carson River Basin National Water-Quality Assessment (NAWQA) pilot study. Four aquifer systems have been de- lineated in the study area. Principal aquifers are unconsolidated deposits at altitudes of less than 4,900 feet above sea level and more than 50 feet below land surface. Shallow aquifers are at altitudes of less than 4,900 feet and less than 50 feet below land surface. Upland aquifers are above 4,900 feet and provide recharge to the principal aquifers. Thermal aquifers, defined as those having a water temperature greater than 30 degrees Celsius, are also present. Ground water used in Dayton, Stagecoach, and Churchill Valleys is pumped from principal aquifers in unconsolidated basin-fill deposits. Ground water in these aquifers originates as precipitation in the adjacent mountains and is recharged by the Carson River and by underflow from adjacent upstream valleys. Ground-water flow is generally parallel to the direction of surface-water flow in the Carson River. Ground water is discharged by pumping, evapo- transpiration, and underflow into the Carson River. The results of geochemical modeling indicate that as ground water moves from upland aquifers in mountainous recharge areas to principal aquifers in basin-fill deposits, the following processes probably occur: (1) plagioclase feldspar, sodium chloride, gypsum (or pyrite), potassium feldspar, and biotite dissolve; (2) calcite precipitates; (3) kaolinite forms; (4) small amounts of calcium and magnesium in the water exchange for potassium on aquifer minerals; and (5) carbon dioxide is gained or lost. The geochemical models are consistent with (1) phases identified in basin- fill sediments; (2) chemical activity of major cations and silica; (3) saturation indices of calcite and amorphous silica; (4) phase relations for aluminosilicate minerals indicated by activity diagrams; and

  1. Potential effects of groundwater pumping on water levels, phreatophytes, and spring discharges in Spring and Snake Valleys, White Pine County, Nevada, and adjacent areas in Nevada and Utah

    Science.gov (United States)

    Halford, Keith J.; Plume, Russell W.

    2011-01-01

    Assessing hydrologic effects of developing groundwater supplies in Snake Valley required numerical, groundwater-flow models to estimate the timing and magnitude of capture from streams, springs, wetlands, and phreatophytes. Estimating general water-table decline also required groundwater simulation. The hydraulic conductivity of basin fill and transmissivity of basement-rock distributions in Spring and Snake Valleys were refined by calibrating a steady state, three-dimensional, MODFLOW model of the carbonate-rock province to predevelopment conditions. Hydraulic properties and boundary conditions were defined primarily from the Regional Aquifer-System Analysis (RASA) model except in Spring and Snake Valleys. This locally refined model was referred to as the Great Basin National Park calibration (GBNP-C) model. Groundwater discharges from phreatophyte areas and springs in Spring and Snake Valleys were simulated as specified discharges in the GBNP-C model. These discharges equaled mapped rates and measured discharges, respectively. Recharge, hydraulic conductivity, and transmissivity were distributed throughout Spring and Snake Valleys with pilot points and interpolated to model cells with kriging in geologically similar areas. Transmissivity of the basement rocks was estimated because thickness is correlated poorly with transmissivity. Transmissivity estimates were constrained by aquifer-test results in basin-fill and carbonate-rock aquifers. Recharge, hydraulic conductivity, and transmissivity distributions of the GBNP-C model were estimated by minimizing a weighted composite, sum-of-squares objective function that included measurement and Tikhonov regularization observations. Tikhonov regularization observations were equations that defined preferred relations between the pilot points. Measured water levels, water levels that were simulated with RASA, depth-to-water beneath distributed groundwater and spring discharges, land-surface altitudes, spring discharge at

  2. Assessment of regional change in nitrate concentrations in groundwater in the Central Valley, California, USA, 1950s-2000s

    Science.gov (United States)

    Burow, Karen R.; Jurgens, Bryant C.; Belitz, Kenneth; Dubrovsky, Neil M.

    2013-01-01

    A regional assessment of multi-decadal changes in nitrate concentrations was done using historical data and a spatially stratified non-biased approach. Data were stratified into physiographic subregions on the basis of geomorphology and soils data to represent zones of historical recharge and discharge patterns in the basin. Data were also stratified by depth to represent a shallow zone generally representing domestic drinking-water supplies and a deep zone generally representing public drinking-water supplies. These stratifications were designed to characterize the regional extent of groundwater with common redox and age characteristics, two factors expected to influence changes in nitrate concentrations over time. Overall, increasing trends in nitrate concentrations and the proportion of nitrate concentrations above 5 mg/L were observed in the east fans subregion of the Central Valley. Whereas the west fans subregion has elevated nitrate concentrations, temporal trends were not detected, likely due to the heterogeneous nature of the water quality in this area and geologic sources of nitrate, combined with sparse and uneven data coverage. Generally low nitrate concentrations in the basin subregion are consistent with reduced geochemical conditions resulting from low permeability soils and higher organic content, reflecting the distal portions of alluvial fans and historical groundwater discharge areas. Very small increases in the shallow aquifer in the basin subregion may reflect downgradient movement of high nitrate groundwater from adjacent areas or overlying intensive agricultural inputs. Because of the general lack of regionally extensive long-term monitoring networks, the results from this study highlight the importance of placing studies of trends in water quality into regional context. Earlier work concluded that nitrate concentrations were steadily increasing over time in the eastern San Joaquin Valley, but clearly those trends do not apply to other

  3. Ground-water discharge determined from measurements of evapotranspiration, other available hydrologic components, and shallow water-level changes, Oasis Valley, Nye County, Nevada

    International Nuclear Information System (INIS)

    Reiner, S.R.; Laczniak, R.J.; DeMeo, G.A.; Smith LaRue, J.; Elliott, P.E.; Nylund, W.E.; Fridrich, C.J.

    2002-01-01

    Oasis Valley is an area of natural ground-water discharge within the Death Valley regional ground-water flow system of southern Nevada and adjacent California. Ground water discharging at Oasis Valley is replenished from inflow derived from an extensive recharge area that includes the northwestern part of the Nevada Test Site (NTS). Because nuclear testing has introduced radionuclides into the subsurface of the NTS, the U.S. Department of Energy currently is investigating the potential transport of these radionuclides by ground water flow. To better evaluate any potential risk associated with these test-generated contaminants, a number of studies were undertaken to accurately quantify discharge from areas downgradient in the regional ground-water flow system from the NTS. This report refines the estimate of ground-water discharge from Oasis Valley. Ground-water discharge from Oasis Valley was estimated by quantifying evapotranspiration (ET), estimating subsurface outflow, and compiling ground-water withdrawal data. ET was quantified by identifying areas of ongoing ground-water ET, delineating areas of ET defined on the basis of similarities in vegetation and soil-moisture conditions and computing ET rates for each of the delineated areas. A classification technique using spectral-reflectance characteristics determined from satellite imagery acquired in 1992 identified eight unique areas of ground-water ET. These areas encompass about 3,426 acres of sparsely to densely vegetated grassland, shrubland, wetland, and open water. Annual ET rates in Oasis Valley were computed with energy-budget methods using micrometeorological data collected at five sites. ET rates range from 0.6 foot per year in a sparse, dry saltgrass environment to 3.1 feet per year in dense meadow vegetation. Mean annual ET from Oasis Valley is estimated to be about 7,800 acre-feet. Mean annual ground-water discharge by ET from Oasis Valley, determined by removing the annual local precipitation

  4. Guide to user modification of a three-dimensional digital ground-water model for Salt Lake Valley, Utah

    Science.gov (United States)

    Seiler, R.L.; Waddell, K.M.

    1986-01-01

    A digital-computer model was calibrated to simulate, in three dimensions, the ground-water flow in the principal and shallow-unconfined aquifers in Salt Lake Valley, Utah. The model can be used to predict water-level and waterbudget changes that would be caused by changes in well recharge or discharge. This report shows how a user can revise the input data so that recharging or discharging wells may be simulated and how stress-period intervals can be varied to simulate different periods of recharge or discharge.

  5. Correlation between geology and radon levels in groundwater, soil and indoor air in Bhilangana Valley, Garhwal Himalaya, India

    International Nuclear Information System (INIS)

    Choubey, V.M.; Ramola, R.C.

    1997-01-01

    Radon concentrations were measured in soil, air and groundwater in Bhilangana Valley, Garhwal Himalaya, India by using an LR-115 plastic track detector and radon emanometer. Radon concentrations were found to vary from 1 KBq/m 3 to 57 KBq/m 3 in soil, 5 Bq/l to 887 Bq/l in water and 95 Bq/m 3 to 208 Bq/m 3 in air. The recorded values are quite high due to associated uranium mineralization in the area. Radon concentration was also found to depend on the tectonic structure and geology of the area. (orig.)

  6. Importance of the vertical component of groundwater flow: a hydrogeochemical approach in the valley of San Luis Potosi, Mexico

    Science.gov (United States)

    Carrillo-Rivera, J. J.; Cardona, A.; Moss, D.

    1996-11-01

    Fractured volcanics exert a control on groundwater flow in the San Luis Potosi (SLP) valley. The chemical composition and temperature of water pumped from boreholes partially penetrating the fractured volcanics indicate that the produced water originates from an upward vertical flow. Most of the thermal groundwater has been detected in areas related to regional faults and lineaments. Intensive and uncontrolled pumping from the upper {1}/{4} of the aquifer (total depth > 1500 m) causes the rise of water from a deep regional flow system that mixes with the shallower waters. The deep waters contain high fluoride concentrations that contaminate the mixture and cause substantial health related effects. The recharge controls on the regional flow system require further research; however, hydrogeochemical evidence supports the view that the origin of this recharge is limited to the western bounding Sierra Madre Occidental. Higher levels of dissolved Na +, Li +, F - (and SO 4-2) derived from Tertiary volcanics have been introduced into the exploited region; the concentrations indicate lengthy and deep circulation flow. Li + concentration was used as an indicator of groundwater residence time, and therefore of the length of the groundwater flow path. Hydrogeochemical interpretation indicates the presence of three flow systems: a shallow local one controlled by a clay layer that subcrops most of the valley floor, an intermediate system in which water infiltrates just beyond the boundary of the clay layer, and a deep regional system which originates outside the surface catchment. The local and intermediate systems circulate through materials with comparatively low hydraulic conductivity. Low Cl - concentrations suggest rapid flow in the regional system. Concentrations of Li + and F - can be used to calculate percentages of waters in mixtures of regional and intermediate flows. Concentrations of Na +, Ca 2+ and SO 4-2 appear to be controlled by water-rock reactions

  7. Inverse geochemical modeling of groundwater evolution with emphasis on arsenic in the Mississippi River Valley alluvial aquifer, Arkansas (USA)

    Science.gov (United States)

    Sharif, M.U.; Davis, R.K.; Steele, K.F.; Kim, B.; Kresse, T.M.; Fazio, J.A.

    2008-01-01

    Inverse geochemical modeling (PHREEQC) was used to identify the evolution of groundwater with emphasis on arsenic (As) release under reducing conditions in the shallow (25-30 m) Mississippi River Valley Alluvial aquifer, Arkansas, USA. The modeling was based on flow paths defined by high-precision (??2 cm) water level contour map; X-ray diffraction (XRD), scanning electron microscopic (SEM), and chemical analysis of boring-sediments for minerals; and detailed chemical analysis of groundwater along the flow paths. Potential phases were constrained using general trends in chemical analyses data of groundwater and sediments, and saturation indices data (MINTEQA2) of minerals in groundwater. Modeling results show that calcite, halite, fluorite, Fe oxyhydroxide, organic matter, H2S (gas) were dissolving with mole transfers of 1.40E - 03, 2.13E - 04, 4.15E - 06, 1.25E + 01, 3.11, and 9.34, respectively along the dominant flow line. Along the same flow line, FeS, siderite, and vivianite were precipitating with mole transfers of 9.34, 3.11, and 2.64E - 07, respectively. Cation exchange reactions of Ca2+ (4.93E - 04 mol) for Na+ (2.51E - 04 mol) on exchange sites occurred along the dominant flow line. Gypsum dissolution reactions were dominant over calcite dissolution in some of the flow lines due to the common ion effect. The concentration of As in groundwater ranged from rate of reduction of Fe oxyhydroxide over SO42 - with co-precipitation of As into sulfide is the limiting factor controlling dissolved As in groundwater. ?? 2007 Elsevier B.V. All rights reserved.

  8. Groundwater and surface water flow to the Merced River, Yosemite Valley, California: 36Cl and Cl- evidence

    Science.gov (United States)

    Shaw, Glenn D.; Conklin, Martha H.; Nimz, Gregory J.; Liu, Fengjing

    2014-03-01

    Our current understanding of water fluxes and flow paths within the mountain block is limited, and improved understanding is necessary to assess hydrology more accurately above the mountain front. Source waters and the processes controlling their mixing were characterized in the Merced River basin within Yosemite National Park, California, using 36Cl and Cl-, supported by 222Rn, δ18O, δD, and streamflow data. Streams, snow, groundwater, and springs were sampled seasonally from July 2004 to October 2007. Three source water end-members were identified: (i) near surface runoff of recent meltwater containing bomb-pulse 36Cl (36ClBP), (ii) shallow, evapotranspired groundwater, and (iii) groundwater containing Cl- derived through extended rock interaction. Both groundwater end-members mix in Yosemite Valley and then later discharge to the Merced River. Near surface runoff dominates all stream hydrographs during snowmelt, whereas the two groundwater end-members become significantly more important during base flow. Tributaries consist of mixtures of the shallow evapotranspired groundwater and near surface runoff, whereas the Merced River is composed of the mixture of all source water end-members. Snow is not an obvious end-member, and elevated 36ClBP in the near surface runoff suggests that 36ClBP was retained efficiently, and is being slowly released as meltwater interacts with the soil. The use of 36Cl as a natural tracer is important in revealing the processes controlling streamflow generation in large montane catchments and the results will be helpful in configuring and calibrating hydrologic models.

  9. Hydrogeology of, and ground-water flow in, a valley-fill and carbonate-rock aquifer system near Long Valley in the New Jersey Highlands

    Science.gov (United States)

    Nicholson, R.S.; McAuley, S.D.; Barringer, J.L.; Gordon, A.D.

    1996-01-01

    The hydrogeology of and ground-water flow in a valley-fill and carbonate-rock aquifer system were evaluated by using numerical-modeling techniques and geochemical interpretations to address concerns about the adequacy of the aquifer system to meet increasing demand for water. The study was conducted during 1987-90 by the U.S. Geological Survey, in cooperation with the New Jersey Department of Environmental Protection and Energy. The effects of recent and anticipated ground-water withdrawals on water levels, stream base flows, and water budgets were estimated. Simulation results indicate that recent withdrawals of 4.7 million gallons per day have resulted in water-level declines of up to 35 feet. Under conditions of increases in withdrawals of 121 percent, water levels would decline up to an additional 28 feet. The magnitude of predicted average base-flow depletion, when compared with historic low flows, indicates that projected increases in withdrawals may substantially deplete seasonal low flow of Drakes Brook and South Branch Raritan River. Results of a water-budget analysis indicate that the sources of water to additional supply wells would include leakage from the overlying valley-fill aquifer and induced leakage of surface water into the aquifer system. Results of water-quality analyses indicate that human activities are affecting the quality of the ground water. With the exception of an elevated iron concentration in water from one well, concentrations of inorganic constituents in water from 75 wells did not exceed New Jersey primary or secondary drinking-water regulations. Volatile organic compounds were detected in water from several wells; in two samples, concentrations of specific compounds exceeded drinking-water regulations.

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

    Science.gov (United States)

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

    2013-05-01

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

  11. Bayesian nitrate source apportionment to individual groundwater wells in the Central Valley by use of elemental and isotopic tracers

    Science.gov (United States)

    Ransom, Katherine M.; Grote, Mark N.; Deinhart, Amanda; Eppich, Gary; Kendall, Carol; Sanborn, Matthew E.; Souders, A. Kate; Wimpenny, Joshua; Yin, Qing-zhu; Young, Megan; Harter, Thomas

    2016-07-01

    Groundwater quality is a concern in alluvial aquifers that underlie agricultural areas, such as in the San Joaquin Valley of California. Shallow domestic wells (less than 150 m deep) in agricultural areas are often contaminated by nitrate. Agricultural and rural nitrate sources include dairy manure, synthetic fertilizers, and septic waste. Knowledge of the relative proportion that each of these sources contributes to nitrate concentration in individual wells can aid future regulatory and land management decisions. We show that nitrogen and oxygen isotopes of nitrate, boron isotopes, and iodine concentrations are a useful, novel combination of groundwater tracers to differentiate between manure, fertilizers, septic waste, and natural sources of nitrate. Furthermore, in this work, we develop a new Bayesian mixing model in which these isotopic and elemental tracers were used to estimate the probability distribution of the fractional contributions of manure, fertilizers, septic waste, and natural sources to the nitrate concentration found in an individual well. The approach was applied to 56 nitrate-impacted private domestic wells located in the San Joaquin Valley. Model analysis found that some domestic wells were clearly dominated by the manure source and suggests evidence for majority contributions from either the septic or fertilizer source for other wells. But, predictions of fractional contributions for septic and fertilizer sources were often of similar magnitude, perhaps because modeled uncertainty about the fraction of each was large. For validation of the Bayesian model, fractional estimates were compared to surrounding land use and estimated source contributions were broadly consistent with nearby land use types.

  12. Ground-Water Quality Data in the Middle Sacramento Valley Study Unit, 2006 - Results from the California GAMA Program

    Science.gov (United States)

    Schmitt, Stephen J.; Fram, Miranda S.; Milby Dawson, Barbara J.; Belitz, Kenneth

    2008-01-01

    Ground-water quality in the approximately 3,340 square mile Middle Sacramento Valley study unit (MSACV) was investigated from June through September, 2006, as part of the California Groundwater Ambient Monitoring and Assessment (GAMA) program. The GAMA Priority Basin Assessment project was developed in response to the Groundwater Quality Monitoring Act of 2001 and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). The Middle Sacramento Valley study was designed to provide a spatially unbiased assessment of raw ground-water quality within MSACV, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from 108 wells in Butte, Colusa, Glenn, Sutter, Tehama, Yolo, and Yuba Counties. Seventy-one wells were selected using a randomized grid-based method to provide statistical representation of the study unit (grid wells), 15 wells were selected to evaluate changes in water chemistry along ground-water flow paths (flow-path wells), and 22 were shallow monitoring wells selected to assess the effects of rice agriculture, a major land use in the study unit, on ground-water chemistry (RICE wells). The ground-water samples were analyzed for a large number of synthetic organic constituents (volatile organic compounds [VOCs], gasoline oxygenates and degradates, pesticides and pesticide degradates, and pharmaceutical compounds), constituents of special interest (perchlorate, N-nitrosodimethylamine [NDMA], and 1,2,3-trichloropropane [1,2,3-TCP]), inorganic constituents (nutrients, major and minor ions, and trace elements), radioactive constituents, and microbial indicators. Naturally occurring isotopes (tritium, and carbon-14, and stable isotopes of hydrogen, oxygen, nitrogen, and carbon), and dissolved noble gases also were measured to help identify the sources and ages of the sampled ground water. Quality-control samples (blanks

  13. A hybrid machine learning model to estimate nitrate contamination of production zone groundwater in the Central Valley, California

    Science.gov (United States)

    Ransom, K.; Nolan, B. T.; Faunt, C. C.; Bell, A.; Gronberg, J.; Traum, J.; Wheeler, D. C.; Rosecrans, C.; Belitz, K.; Eberts, S.; Harter, T.

    2016-12-01

    A hybrid, non-linear, machine learning statistical model was developed within a statistical learning framework to predict nitrate contamination of groundwater to depths of approximately 500 m below ground surface in the Central Valley, California. A database of 213 predictor variables representing well characteristics, historical and current field and county scale nitrogen mass balance, historical and current landuse, oxidation/reduction conditions, groundwater flow, climate, soil characteristics, depth to groundwater, and groundwater age were assigned to over 6,000 private supply and public supply wells measured previously for nitrate and located throughout the study area. The machine learning method, gradient boosting machine (GBM) was used to screen predictor variables and rank them in order of importance in relation to the groundwater nitrate measurements. The top five most important predictor variables included oxidation/reduction characteristics, historical field scale nitrogen mass balance, climate, and depth to 60 year old water. Twenty-two variables were selected for the final model and final model errors for log-transformed hold-out data were R squared of 0.45 and root mean square error (RMSE) of 1.124. Modeled mean groundwater age was tested separately for error improvement in the model and when included decreased model RMSE by 0.5% compared to the same model without age and by 0.20% compared to the model with all 213 variables. 1D and 2D partial plots were examined to determine how variables behave individually and interact in the model. Some variables behaved as expected: log nitrate decreased with increasing probability of anoxic conditions and depth to 60 year old water, generally decreased with increasing natural landuse surrounding wells and increasing mean groundwater age, generally increased with increased minimum depth to high water table and with increased base flow index value. Other variables exhibited much more erratic or noisy behavior in

  14. Hydrogeology of, and Simulation of Ground-Water Flow In, the Pohatcong Valley, Warren County, New Jersey

    Science.gov (United States)

    Carleton, Glen B.; Gordon, Alison D.

    2007-01-01

    A numerical ground-water-flow model was constructed to simulate ground-water flow in the Pohatcong Valley, including the area within the U.S. Environmental Protection Agency Pohatcong Valley Ground Water Contamination Site. The area is underlain by glacial till, alluvial sediments, and weathered and competent carbonate bedrock. The northwestern and southeastern valley boundaries are regional-scale thrust faults and ridges underlain by crystalline rocks. The unconsolidated sediments and weathered bedrock form a minor surficial aquifer and the carbonate rocks form a highly transmissive fractured-rock aquifer. Ground-water flow in the carbonate rocks is primarily downvalley towards the Delaware River, but the water discharges through the surficial aquifer to Pohatcong Creek under typical conditions. The hydraulic characteristics of the carbonate-rock aquifer are highly heterogeneous. Horizontal hydraulic conductivities span nearly five orders of magnitude, from 0.5 feet per day (ft/d) to 1,800 ft/d. The maximum transmissivity calculated is 37,000 feet squared per day. The horizontal hydraulic conductivities calculated from aquifer tests using public supply wells open to the Leithsville Formation and Allentown Dolomite are 34 ft/d (effective hydraulic conductivity) and 85 to 190 ft/d (minimum and maximum hydraulic conductivity, respectively, yielding a horizontal anisotropy ratio of 0.46). Stream base-flow data were used to estimate the net gain (or loss) for selected reaches on Brass Castle Creek, Shabbecong Creek, three smaller tributaries to Pohatcong Creek, and for five reaches on Pohatcong Creek. Estimated mean annual base flows for Brass Castle Creek, Pohatcong Creek at New Village, and Pohatcong Creek at Carpentersville (from correlations of partial- and continuous-record stations) are 2.4, 25, and 45 cubic feet per second (ft3/s) (10, 10, and 11 inches per year (in/yr)), respectively. Ground-water ages estimated using sulfur hexafluoride (SF6

  15. Groundwater.

    Science.gov (United States)

    Braids, Olin C.; Gillies, Nola P.

    1978-01-01

    Presents a literature review of groundwater quality covering publications of 1977. This review includes: (1) sources of groundwater contamination; and (2) management of groundwater. A list of 59 references is also presented. (HM)

  16. Modeling The Evolution Of A Regional Aquifer System With The California Central Valley Groundwater-Surface Water Simulation Model (C2VSIM)

    Science.gov (United States)

    Brush, C. F.; Dogrul, E. C.; Kadir, T. N.; Moncrief, M. R.; Shultz, S.; Tonkin, M.; Wendell, D.

    2006-12-01

    The finite element application IWFM has been used to develop an integrated groundwater-surface water model for California's Central Valley, an area of ~50,000 km2, to simulate the evolution of the groundwater flow system and historical groundwater-surface water interactions on a monthly time step from October 1921 to September 2003. The Central Valley's hydrologic system changed significantly during this period. Prior to 1920, most surface water flowed unimpeded from source areas in the mountains surrounding the Central Valley through the Sacramento-San Joaquin Delta to the Pacific Ocean, and groundwater largely flowed from recharge areas on the valley rim to discharge as evapotransipration in extensive marshes along the valley's axis. Rapid agricultural development led to increases in groundwater pumping from ~0.5 km3/yr in the early 1920's to 13-18 km3/yr in the 1940's to 1970's, resulting in strong vertical head gradients, significant head declines throughout the valley, and subsidence of >0.3 m over an area of 13,000 km2. Construction of numerous dams and development of an extensive surface water delivery network after 1950 altered the surface water flow regime and reduced groundwater pumping to the current ~10 km3/yr, increasing net recharge and leading to local head gradient reversals and water level recoveries. A model calibrated to the range of historical flow regimes in the Central Valley will provide robust estimations of stream-groundwater interactions for a range of projected future scenarios. C2VSIM uses the IWFM application to simulate a 3-D finite element groundwater flow process dynamically coupled with 1-D land surface, stream flow, lake and unsaturated zone processes. The groundwater flow system is represented with three layers each having 1393 elements. Land surface processes are simulated using 21 subregions corresponding to California DWR water-supply planning areas. The surface-water network is simulated using 431 stream nodes representing 72

  17. Groundwater-Quality Data in the Antelope Valley Study Unit, 2008: Results from the California GAMA Program

    Science.gov (United States)

    Schmitt, Stephen J.; Milby Dawson, Barbara J.; Belitz, Kenneth

    2009-01-01

    Groundwater quality in the approximately 1,600 square-mile Antelope Valley study unit (ANT) was investigated from January to April 2008 as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Project was developed in response to the Groundwater Quality Monitoring Act of 2001, and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). The study was designed to provide a spatially unbiased assessment of the quality of raw groundwater used for public water supplies within ANT, and to facilitate statistically consistent comparisons of groundwater quality throughout California. Samples were collected from 57 wells in Kern, Los Angeles, and San Bernardino Counties. Fifty-six of the wells were selected using a spatially distributed, randomized, grid-based method to provide statistical representation of the study area (grid wells), and one additional well was selected to aid in evaluation of specific water-quality issues (understanding well). The groundwater samples were analyzed for a large number of organic constituents (volatile organic compounds [VOCs], gasoline additives and degradates, pesticides and pesticide degradates, fumigants, and pharmaceutical compounds), constituents of special interest (perchlorate, N-nitrosodimethylamine [NDMA], and 1,2,3-trichloropropane [1,2,3-TCP]), naturally occurring inorganic constituents (nutrients, major and minor ions, and trace elements), and radioactive constituents (gross alpha and gross beta radioactivity, radium isotopes, and radon-222). Naturally occurring isotopes (strontium, tritium, and carbon-14, and stable isotopes of hydrogen and oxygen in water), and dissolved noble gases also were measured to help identify the sources and ages of the sampled groundwater. In total, 239 constituents and water-quality indicators (field parameters) were investigated. Quality

  18. Ground-Water Quality Data in the Coachella Valley Study Unit, 2007: Results from the California GAMA Program

    Science.gov (United States)

    Goldrath, Dara A.; Wright, Michael T.; Belitz, Kenneth

    2009-01-01

    Ground-water quality in the approximately 820 square-mile Coachella Valley Study Unit (COA) was investigated during February and March 2007 as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Project was developed in response to the Groundwater Quality Monitoring Act of 2001, and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). The study was designed to provide a spatially unbiased assessment of raw ground water used for public-water supplies within the Coachella Valley, and to facilitate statistically consistent comparisons of ground-water quality throughout California. Samples were collected from 35 wells in Riverside County. Nineteen of the wells were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study unit (grid wells). Sixteen additional wells were sampled to evaluate changes in water chemistry along selected ground-water flow paths, examine land use effects on ground-water quality, and to collect water-quality data in areas where little exists. These wells were referred to as 'understanding wells'. The ground-water samples were analyzed for a large number of organic constituents (volatile organic compounds [VOC], pesticides and pesticide degradates, pharmaceutical compounds, and potential wastewater-indicator compounds), constituents of special interest (perchlorate and 1,2,3-trichloropropane [1,2,3-TCP]), naturally occurring inorganic constituents (nutrients, major and minor ions, and trace elements), radioactive constituents, and microbial indicators. Naturally occurring isotopes (uranium, tritium, carbon-14, and stable isotopes of hydrogen, oxygen, and boron), and dissolved noble gases (the last in collaboration with Lawrence Livermore National Laboratory) also were measured to help identify the source and age of the sampled

  19. Ground-Water Storage Change and Land Subsidence in Tucson Basin and Avra Valley, Southeastern Arizona, 1998-2002

    Science.gov (United States)

    Pool, Donald R.; Anderson, Mark T.

    2008-01-01

    Gravity and land subsidence were measured annually at wells and benchmarks within two networks in Tucson Basin and Avra Valley from 1998 to 2002. Both networks are within the Tucson Active Management Area. Annual estimates of ground-water storage change, ground-water budgets, and land subsidence were made based on the data. Additionally, estimates of specific yield were made at wells within the monitored region. Increases in gravity and water-level rises followed above-average natural recharge during winter 1998 in Tucson Basin. Overall declining gravity and water-level trends from 1999 to 2002 in Tucson Basin reflected general declining ground-water storage conditions and redistribution of the recent recharge throughout a larger region of the aquifer. The volume of stored ground-water in the monitored portion of Tucson Basin increased 200,000 acre-feet from December 1997 to February 1999; however, thereafter an imbalance in ground-water pumpage in excess of recharge led to a net storage loss for the monitoring period by February 2002. Ground-water storage in Avra Valley increased 70,000 acre-feet during the monitoring period, largely as a result of artificial and incidental recharge in the monitored region. The water-budget for the combined monitored regions of Tucson Basin and Avra Valley was dominated by about 460,000 acre-feet of recharge during 1998 followed by an average-annual recharge rate of about 80,000 acre-feet per year from 1999 to 2002. Above-average recharge during winter 1998, followed by average-annual deficit conditions, resulted in an overall balanced water budget for the monitored period. Monitored variations in storage compared well with simulated average-annual conditions, except for above-average recharge from 1998 to 1999. The difference in observed and simulated conditions indicate that ground-water flow models can be improved by including climate-related variations in recharge rates rather than invariable rates of average-annual recharge

  20. Plant Water Use in Owens Valley, CA: Understanding the Influence of Climate and Depth to Groundwater

    OpenAIRE

    Pataki, Diane E

    2008-01-01

    There is a long-standing controversy in Owens Valley, California about the potential impacts of water exports on the local ecosystem. It is currently extremely difficult to attribute changes in plant cover and community composition to hydrologic change, as the interactions between ecological and hydrologic processes are relatively poorly understood. Underlying predictions about losses of grasslands and expansion of shrublands in response to declining water tables in Owens Valley are assumptio...

  1. Temporal trends in concentrations of DBCP and nitrate in groundwater in the eastern San Joaquin Valley, California, USA

    Science.gov (United States)

    Burow, K.R.; Dubrovsky, N.M.; Shelton, James L.

    2007-01-01

    Temporal monitoring of the pesticide 1,2-dibromo-3-chloropropane (DBCP) and nitrate and indicators of mean groundwater age were used to evaluate the transport and fate of agricultural chemicals in groundwater and to predict the long-term effects in the regional aquifer system in the eastern San Joaquin Valley, California. Twenty monitoring wells were installed on a transect along an approximate groundwater flow path. Concentrations of DBCP and nitrate in the wells were compared to concentrations in regional areal monitoring networks. DBCP persists at concentrations above the US Environmental Protection Agency's maximum contaminant level (MCL) at depths of nearly 40 m below the water table, more than 25 years after it was banned. Nitrate concentrations above the MCL reached depths of more than 20 m below the water table. Because of the intensive pumping and irrigation recharge, vertical flow paths are dominant. High concentrations (above MCLs) in the shallow part of the regional aquifer system will likely move deeper in the system, affecting both domestic and public-supply wells. The large fraction of old water (unaffected by agricultural chemicals) in deep monitoring wells suggests that it could take decades for concentrations to reach MCLs in deep, long-screened public-supply wells, however. ?? Springer-Verlag 2007.

  2. Simulation of Multiscale Ground-Water Flow in Part of the Northeastern San Joaquin Valley, California

    Science.gov (United States)

    Phillips, Steven P.; Green, Christopher T.; Burow, Karen R.; Shelton, Jennifer L.; Rewis, Diane L.

    2007-01-01

    The transport and fate of agricultural chemicals in a variety of environmental settings is being evaluated as part of the U.S. Geological Survey (USGS) National Water-Quality Assessment Program. One of the locations being evaluated is a 2,700-km2 (square kilometer) regional study area in the northeastern San Joaquin Valley surrounding the city of Modesto, an area dominated by irrigated agriculture in a semi-arid climate. Ground water is a key source of water for irrigation and public supply, and exploitation of this resource has altered the natural flow system. The aquifer system is predominantly alluvial, and an unconfined to semiconfined aquifer overlies a confined aquifer in the southwestern part of the study area; these aquifers are separated by the lacustrine Corcoran Clay. A regional-scale 16-layer steady-state model of ground-water flow in the aquifer system in the regional study area was developed to provide boundary conditions for an embedded 110-layer steady-state local-scale model of part of the aquifer system overlying the Corcoran Clay along the Merced River. The purpose of the local-scale model was to develop a better understanding of the aquifer system and to provide a basis for simulation of reactive transport of agricultural chemicals. The heterogeneity of aquifer materials was explicitly incorporated into the regional and local models using information from geologic and drillers? logs of boreholes. Aquifer materials were differentiated in the regional model by the percentage of coarse-grained sediments in a cell, and in the local model by four hydrofacies (sand, silty sand, silt, and clay). The calibrated horizontal hydraulic conductivity values of the coarse-grained materials in the zone above the Corcoran Clay in the regional model and of the sand hydrofacies used in the local model were about equal (30?80 m/d [meter per day]), and the vertical hydraulic conductivity values in the same zone of the regional model (median of 0.012 m/d), which is

  3. Geology, water-quality, hydrology, and geomechanics of the Cuyama Valley groundwater basin, California, 2008--12

    Science.gov (United States)

    Everett, Rhett; Gibbs, Dennis R.; Hanson, Randall T.; Sweetkind, Donald S.; Brandt, Justin T.; Falk, Sarah E.; Harich, Christopher R.

    2013-01-01

    To assess the water resources of the Cuyama Valley groundwater basin in Santa Barbara County, California, a series of cooperative studies were undertaken by the U.S. Geological Survey and the Santa Barbara County Water Agency. Between 2008 and 2012, geologic, water-quality, hydrologic and geomechanical data were collected from selected sites throughout the Cuyama Valley groundwater basin. Geologic data were collected from three multiple-well groundwater monitoring sites and included lithologic descriptions of the drill cuttings, borehole geophysical logs, temperature logs, as well as bulk density and sonic velocity measurements of whole-core samples. Generalized lithologic characterization from the monitoring sites indicated the water-bearing units in the subsurface consist of unconsolidated to partly consolidated sand, gravel, silt, clay, and occasional cobbles within alluvial fan and stream deposits. Analysis of geophysical logs indicated alternating layers of finer- and coarser-grained material that range from less than 1 foot to more than 20 feet thick. On the basis of the geologic data collected, the principal water-bearing units beneath the monitoring-well sites were found to be composed of younger alluvium of Holocene age, older alluvium of Pleistocene age, and the Tertiary-Quaternary Morales Formation. At all three sites, the contact between the recent fill and younger alluvium is approximately 20 feet below land surface. Water-quality samples were collected from 12 monitoring wells, 27 domestic and supply wells, 2 springs, and 4 surface-water sites and were analyzed for a variety of constituents that differed by site, but, in general, included trace elements; nutrients; dissolved organic carbon; major and minor ions; silica; total dissolved solids; alkalinity; total arsenic and iron; arsenic, chromium, and iron species; and isotopic tracers, including the stable isotopes of hydrogen and oxygen, activities of tritium, and carbon-14 abundance. Of the 39

  4. Groundwater flow system in the valley of Toluca, Mexico: an assay of natural radionuclide specific activities

    Energy Technology Data Exchange (ETDEWEB)

    Segovia, N.; Tamez, E.; Pena, P.; Acosta, E.; Iturbe, J.L. [ININ, Mexico D.F. (Mexico); Carrillo, J. [UACPyP-CCH, UNAM, Mexico D.F. (Mexico); Armienta, M.A. [IGFUNAM, C. Universitaria, Mexico D.F. (Mexico)

    1999-03-01

    Natural radionuclides and physicochemical parameters have been evaluated in groundwater samples from boreholes belonging to the drinking water supply system of the Toluca City, Mexico. The results obtained for radon and radium, together with the physicochemical parameters of the studied samples, indicate a fast and efficient recharge pattern. The presence of a local and a regional groundwater flows was also observed. The local flow belongs to shallower water, recognized by its low radon content and dissolved ions, as compared with the regional, deeper groundwater flow with a longer residence time.

  5. Methods for using groundwater model predictions to guide hydrogeologic data collection, with application to the Death Valley regional groundwater flow system

    Science.gov (United States)

    Tiedeman, C.R.; Hill, M.C.; D'Agnese, F. A.; Faunt, C.C.

    2003-01-01

    Calibrated models of groundwater systems can provide substantial information for guiding data collection. This work considers using such models to guide hydrogeologic data collection for improving model predictions by identifying model parameters that are most important to the predictions. Identification of these important parameters can help guide collection of field data about parameter values and associated flow system features and can lead to improved predictions. Methods for identifying parameters important to predictions include prediction scaled sensitivities (PSS), which account for uncertainty on individual parameters as well as prediction sensitivity to parameters, and a new "value of improved information" (VOII) method presented here, which includes the effects of parameter correlation in addition to individual parameter uncertainty and prediction sensitivity. In this work, the PSS and VOII methods are demonstrated and evaluated using a model of the Death Valley regional groundwater flow system. The predictions of interest are advective transport paths originating at sites of past underground nuclear testing. Results show that for two paths evaluated the most important parameters include a subset of five or six of the 23 defined model parameters. Some of the parameters identified as most important are associated with flow system attributes that do not lie in the immediate vicinity of the paths. Results also indicate that the PSS and VOII methods can identify different important parameters. Because the methods emphasize somewhat different criteria for parameter importance, it is suggested that parameters identified by both methods be carefully considered in subsequent data collection efforts aimed at improving model predictions.

  6. Analysis of fault rupture potential resulting from large-scale groundwater withdrawal: application to Spring Valley, Nevada

    Science.gov (United States)

    Anderson, B. J.; Schumer, R.; McCoy, S. W.; Hammond, W. C.

    2016-12-01

    Hydrospheric mass changes create subsurface stress perturbations on a scale that can trigger seismic events or accelerate frequency of seismicity on proximal faults. For example, groundwater pumping has been implicated in the 2011 Mw 5.1 earthquake in Lorca, Spain and the 2010 Mw 7.1 El-Mayor Cucapah earthquake in northern Baja California. Previous work on effects of pumping on seismicity is retrospective. We propose a method to assess changes in rupture potential on faults near areas of large-scale groundwater withdrawal ahead before pumping begins. Changes in potentiometric head due to pumping predicted by (MODFLOW) groundwater flow models can be used as the change in surface load input for analytical solutions from Boussinesq [1885] to resolve changes in the subsurface state of stress. Coulomb stress, which quantifies a fault's tendency toward failure, is then resolved on proximal faults. These stress changes can be compared with a 10 kPa stress threshold developed in previous work from statistical correlation of aftershock occurrence with spatial patterns of post-seismic Coulomb stress change on surrounding faults. Stress changes on critical to near-critically stressed faults above the threshold represent a higher likelihood of seismic rupture. The method is applied to a proposed groundwater development project in Spring Valley, Nevada. Proposed pumping in excess of 50 years will result in stress change on the proximal normal fault exceeding the 10 kPa threshold. This change in Coulomb stress is in the realm of earthquake-inducing pumping. However, the low seismic hazard in the region determined from geodetic and paleo-seismic analysis does not suggest imminent rupture.

  7. Land Subsidence and Groundwater Resources Investigations with the Use of D-InSAR, Numerical Modeling, and Field Data in the Toluca Valley, Mexico

    Science.gov (United States)

    Calderhead, A. I.; Martel, R.; Rivera, A.; Garfias, J.; Therrien, R.

    2008-12-01

    In the Toluca Valley, Mexico, urban and industrial growth have resulted in groundwater pumping exceeding recharge. Currently, there is a significant water budget deficit within the basin primarily due to groundwater pumping, and the loss is increasing with time. The stresses on the aquifer have caused significant changes on the water flow patterns, a reversal in the direction of hydraulic gradients, the disappearance of artesian springs and wetlands and noticeable land subsidence within the basin. The focus of this study is the investigation of water resources and land subsidence with the use of Differential Synthetic Aperture Radar Interferometry (D-InSAR), numerical modeling, and field data. The study is divided into two parts: 1) investigation of groundwater depletion in the Toluca Valley; and 2) assessment of land subsidence in the Toluca Valley. A spatially variable recharge model based on the Hydrologic Evaluation of Landfill Performance (HELP) numerical model examines the recharge; pumping estimates are based on a recent census and differences in piezometric surfaces. Currently there is a net loss (recharge - pumping) of over 150 million cubic meters per year of groundwater within the Toluca Basin aquifers. We examine various changes in regional flow patterns, and groundwater levels decline throughout the valley. At the current rate of consumption, groundwater resources are not sustainable for the population of the valley. Directly related to the decrease in groundwater levels is the occurrence of land subsidence. Regional land subsidence of the Toluca Valley is observed with the use of SAR images obtained from the European Space agency's ERS-1, ERS-2 and ENVISAT Satellites and the Canadian Space Agency's RADARSAT-1 satellite. Data from years 1996 to 2008 are used to locate and quantify the subsidence; with subsidence rates reaching more than 15 cm/year. Results from the different sensors are also compared. The findings are verified with in

  8. Understanding surface-water availability in the Central Valley as a means to projecting future groundwater storage with climate variability

    Science.gov (United States)

    Goodrich, J. P.; Cayan, D. R.

    2017-12-01

    California's Central Valley (CV) relies heavily on diverted surface water and groundwater pumping to supply irrigated agriculture. However, understanding the spatiotemporal character of water availability in the CV is difficult because of the number of individual farms and local, state, and federal agencies involved in using and managing water. Here we use the Central Valley Hydrologic Model (CVHM), developed by the USGS, to understand the relationships between climatic variability, surface water inputs, and resulting groundwater use over the historical period 1970-2013. We analyzed monthly surface water diversion data from >500 CV locations. Principle components analyses were applied to drivers constructed from meteorological data, surface reservoir storage, ET, land use cover, and upstream inflows, to feed multiple regressions and identify factors most important in predicting surface water diversions. Two thirds of the diversion locations ( 80% of total diverted water) can be predicted to within 15%. Along with monthly inputs, representations of cumulative precipitation over the previous 3 to 36 months can explain an additional 10% of variance, depending on location, compared to results that excluded this information. Diversions in the southern CV are highly sensitive to inter-annual variability in precipitation (R2 = 0.8), whereby more surface water is used during wet years. Until recently, this was not the case in the northern and mid-CV, where diversions were relatively constant annually, suggesting relative insensitivity to drought. In contrast, this has important implications for drought response in southern regions (eg. Tulare Basin) where extended dry conditions can severely limit surface water supplies and lead to excess groundwater pumping, storage loss, and subsidence. In addition to fueling our understanding of spatiotemporal variability in diversions, our ability to predict these water balance components allows us to update CVHM predictions before

  9. Geochemical tracing and hydrogeochemical modelling of water-rock interactions during salinization of alluvial groundwater (Upper Rhine Valley, France)

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, Y., E-mail: yann.lucas@eost.u-strasbg.fr [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France); Schmitt, A.D., E-mail: anne-desiree.schmitt@univ-fcomte.fr [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France)] [Universite de Franche-Comte et CNRS-UMR 6249, Chrono-Environnement, 16, Route de Gray, 25030 Besancon Cedex (France); Chabaux, F., E-mail: francois.chabaux@eost.u-strasbg.fr [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France); Clement, A.; Fritz, B. [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France); Elsass, Ph. [BRGM, GEODERIS, 1, rue Claude Chappe, 57070 Metz (France); Durand, S. [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France)

    2010-11-15

    Research highlights: {yields} Major and trace elements along with strontium and uranium isotopic ratios show that groundwater geochemical characteristics along the saline plumes cannot reflect a conservative mixing. {yields} A coupled hydrogeochemical model demonstrates that cationic exchange between alkalis from polluted waters and alkaline-earth elements from montmorillonite present in the host rock of the aquifer is the primary process. {yields} The model requires only a small amount of montmorillonite. {yields} It is necessary to consider the pollution history to explain the important chloride, sodium and calcium concentration modifications. {yields} The model shows that the rapidity of the cationic exchange reactions insures a reversibility of the cation fixation on clays in the aquifer. - Abstract: In the southern Upper Rhine Valley, groundwater has undergone intensive saline pollution caused by the infiltration of mining brines, a consequence of potash extraction carried out during the 20th century. Major and trace elements along with Sr and U isotopic ratios show that groundwater geochemical characteristics along the saline plumes cannot reflect conservative mixing between saline waters resulting from the dissolution of waste heaps and one or more unpolluted end-members. The results imply the occurrence of interactions between host rocks and polluted waters, and they suggest that cationic exchange mechanisms are the primary controlling process. A coupled hydrogeochemical model has been developed with the numerical code KIRMAT, which demonstrates that cationic exchange between alkalis from polluted waters and alkaline-earth elements from montmorillonite present in the host rock of the aquifer is the primary process controlling the geochemical evolution of the groundwater. The model requires only a small amount of montmorillonite (between 0.75% and 2.25%), which is in agreement with the observed mineralogical composition of the aquifer. The model also proves

  10. Assessing potential effects of changes in water use with a numerical groundwater-flow model of Carson Valley, Douglas County, Nevada, and Alpine County, California

    Science.gov (United States)

    Yager, Richard M.; Maurer, Douglas K.; Mayers, C.J.

    2012-01-01

    Rapid growth and development within Carson Valley in Douglas County, Nevada, and Alpine County, California, has caused concern over the continued availability of groundwater, and whether the increased municipal demand could either impact the availability of water or result in decreased flow in the Carson River. Annual pumpage of groundwater has increased from less than 10,000 acre feet per year (acre-ft/yr) in the 1970s to about 31,000 acre-ft/yr in 2004, with most of the water used in agriculture. Municipal use of groundwater totaled about 10,000 acre-feet in 2000. In comparison, average streamflow entering the valley from 1940 to 2006 was 344,100 acre-ft/yr, while average flow exiting the valley was 297,400 acre-ft/yr. Carson Valley is underlain by semi-consolidated Tertiary sediments that are exposed on the eastern side and dip westward. Quaternary fluvial and alluvial deposits overlie the Tertiary sediments in the center and western side of the valley. The hydrology of Carson Valley is dominated by the Carson River, which supplies irrigation water for about 39,000 acres of farmland and maintains the water table less than 5 feet (ft) beneath much of the valley floor. Perennial and ephemeral watersheds drain the Carson Range and the Pine Nut Mountains, and mountain-front recharge to the groundwater system from these watersheds is estimated to average 36,000 acre-ft/yr. Groundwater in Carson Valley flows toward the Carson River and north toward the outlet of the Carson Valley. An upward hydraulic gradient exists over much of the valley, and artesian wells flow at land surface in some areas. Water levels declined as much as 15 ft since 1980 in some areas on the eastern side of the valley. Median estimated transmissivities of Quaternary alluvial-fan and fluvial sediments, and Tertiary sediments are 316; 3,120; and 110 feet squared per day (ft2/d), respectively, with larger transmissivity values in the central part of the valley and smaller values near the valley

  11. Natural and Enhanced Attenuation of Soil and Groundwater at the Monument Valley, Arizona, DOE Legacy Waste Site—10281

    Energy Technology Data Exchange (ETDEWEB)

    Waugh, W.J. [S.M. Stoller Corporation, Grand Junction, CO; Miller, D.E. [S.M. Stoller Corporation, Grand Junction, CO; Morris, S.A. [S.M. Stoller Corporation, Grand Junction, CO; Sheader, L.R. [S.M. Stoller Corporation, Grand Junction, CO; Glenn, E.P. [University of Arizona, Tucson, AZ; Moore, D. [University of Arizona, Tucson, AZ; Carroll, K.C. [University of Arizona, Tucson, AZ; Benally, L. [Navajo Nation, Window Rock, AZ; Roanhorse, M. [Navajo Nation, Window Rock, AZ; Bush, R.P. [U.S. Department of Energy, Grand Junction, CO; none,

    2010-03-07

    The U.S. Department of Energy (DOE), the Navajo Nation, and the University of Arizona are exploring natural and enhanced attenuation remedies for groundwater contamination at a former uranium-ore processing site near Monument Valley, Arizona. DOE removed radioactive tailings from the Monument Valley site in 1994. Nitrate and ammonium, waste products of the milling process, remain in an alluvial groundwater plume spreading from the soil source where tailings were removed. Planting and irrigating two native shrubs, fourwing saltbush and black greasewood, markedly reduced both nitrate and ammonium in the source area over an 8-year period. Total nitrogen dropped from 350 mg/kg in 2000 to less than 200 mg/kg in 2008. Most of the reduction is attributable to irrigation-enhanced microbial denitrification rather than plant uptake. However, soil moisture and percolation flux monitoring show that the plantings control the soil water balance in the source area, preventing additional leaching of nitrogen compounds. Enhanced denitrification and phytoremediation also look promising for plume remediation. Microcosm experiments, nitrogen isotopic fractionation analysis, and solute transport modeling results suggest that (1) up to 70 percent of nitrate in the plume has been lost through natural denitrification since the mill was closed in 1968, and (2) injection of ethanol may accelerate microbial denitrification in plume hot spots. A field-scale ethanol injection pilot study is underway. Landscape-scale remote sensing methods developed for the project suggest that transpiration from restored native phreatophyte populations rooted in the aquifer could limit further expansion of the plume. An evaluation of landfarm phytoremediation, the irrigation of native shrub plantings with high nitrate water pumped from the alluvial aquifer, is also underway.

  12. Ground-Water Quality Data in the Santa Clara River Valley Study Unit, 2007: Results from the California GAMA Program

    Science.gov (United States)

    Montrella, Joseph; Belitz, Kenneth

    2009-01-01

    Ground-water quality in the approximately 460-square-mile Santa Clara River Valley study unit (SCRV) was investigated from April to June 2007 as part of the statewide Priority Basin project of the Ground-Water Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin project was developed in response to the Groundwater Quality Monitoring Act of 2001 and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). The study was designed to provide a spatially unbiased assessment of the quality of raw ground water used for public water supplies within SCRV, and to facilitate a statistically consistent basis for comparing water quality throughout California. Fifty-seven ground-water samples were collected from 53 wells in Ventura and Los Angeles Counties. Forty-two wells were selected using a randomized grid-based method to provide statistical representation of the study area (grid wells). Eleven wells (understanding wells) were selected to further evaluate water chemistry in particular parts of the study area, and four depth-dependent ground-water samples were collected from one of the eleven understanding wells to help understand the relation between water chemistry and depth. The ground-water samples were analyzed for a large number of synthetic organic constituents (volatile organic compounds [VOC], pesticides and pesticide degradates, potential wastewater-indicator compounds, and pharmaceutical compounds), a constituent of special interest (perchlorate), naturally occurring inorganic constituents (nutrients, major and minor ions, and trace elements), radioactive constituents, and microbial constituents. Naturally occurring isotopes (tritium, carbon-13, carbon-14 [abundance], stable isotopes of hydrogen and oxygen in water, stable isotopes of nitrogen and oxygen in nitrate, chlorine-37, and bromine-81), and dissolved noble gases also were measured to help identify the source

  13. Use of environmental tracers to evaluate ground-water age and water-quality trends in a buried-valley aquifer, Dayton area, southwestern, Ohio

    Science.gov (United States)

    Rowe, Gary L.; Shapiro, Stephanie Dunkle; Schlosser, Peter

    1999-01-01

    Chlorofluorocarbons (CFC method) and tritium and helium isotopes (3H-3He method) were used as environmental tracers to estimate ground-water age in conjunction with efforts to develop a regional ground-water flow model of the buried-valley aquifer in the Dayton area, southwestern Ohio. This report describes results of CFC and water-quality sampling, summarizes relevant aspects of previously published work, and describes the use of 3H-3He ages to characterize temporal trends in ground-water quality of the buried-valley aquifer near Dayton, Ohio. Results of CFC sampling indicate that approximately 25 percent of the 137 sampled wells were contaminated with excess CFC's that rendered the ground water unsuitable for age dating. Evaluation of CFC ages obtained for the remaining samples indicated that the CFC compounds used for dating were being affected by microbial degradation. The degradation occurred under anoxic conditions that are found in most parts of the buried-valley aquifer. As a result, ground-water ages derived by the CFC method were too old and were inconsistent with measured tritium concentrations and independently derived 3H-3He ages. Limited data indicate that dissolved methane may play an important role in the degradation of the CFC's. In contrast, the 3H-3He technique was found to yield ground-water ages that were chemically and hydrologically reasonable. Ground-water ages derived by the 3H-3He technique were compared to values for selected water- quality characteristics to evaluate temporal trends in ground-water quality in the buried- valley aquifer. Distinct temporal trends were not identified for pH, alkalinity, or calcium and magnesium because of rapid equilibration of ground-water with calcite and dolomite in aquifer sediments. Temporal trends in which the amount of scatter and the number of outlier concentrations increased as ground-water age decreased were noted for sodium, potassium, boron, bromide, chloride, ammonia, nitrate, phosphate

  14. Status of groundwater quality in the Southern, Middle, and Northern Sacramento Valley study units, 2005-08: California GAMA Priority Basin Project

    Science.gov (United States)

    Bennett, George L.; Fram, Miranda S.; Belitz, Kenneth

    2011-01-01

    Groundwater quality in the Southern, Middle, and Northern Sacramento Valley study units was investigated as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study units are located in California's Central Valley and include parts of Butte, Colusa, Glenn, Placer, Sacramento, Shasta, Solano, Sutter, Tehama, Yolo, and Yuba Counties. The GAMA Priority Basin Project is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey and the Lawrence Livermore National Laboratory. The three study units were designated to provide spatially-unbiased assessments of the quality of untreated groundwater in three parts of the Central Valley hydrogeologic province, as well as to provide a statistically consistent basis for comparing water quality regionally and statewide. Samples were collected in 2005 (Southern Sacramento Valley), 2006 (Middle Sacramento Valley), and 2007-08 (Northern Sacramento Valley). The GAMA studies in the Southern, Middle, and Northern Sacramento Valley were designed to provide statistically robust assessments of the quality of untreated groundwater in the primary aquifer systems that are used for drinking-water supply. The assessments are based on water-quality data collected by the USGS from 235 wells in the three study units in 2005-08, and water-quality data from the California Department of Public Health (CDPH) database. The primary aquifer systems (hereinafter, referred to as primary aquifers) assessed in this study are defined by the depth intervals of the wells in the CDPH database for each study unit. The quality of groundwater in shallow or deep water-bearing zones may differ from quality of groundwater in the primary aquifers; shallow groundwater may be more vulnerable to contamination from the surface. The status of the current quality of the groundwater resource was assessed by using data from samples analyzed for volatile organic

  15. Isotopic composition in precipitation and groundwater in the northern mountainous region of the Central Valley of Costa Rica.

    Science.gov (United States)

    Sánchez-Murillo, Ricardo; Esquivel-Hernández, Germain; Sáenz-Rosales, Oscar; Piedra-Marín, Gilberto; Fonseca-Sánchez, Alicia; Madrigal-Solís, Helga; Ulloa-Chaverri, Franz; Rojas-Jiménez, Luis D; Vargas-Víquez, José A

    2017-03-01

    The linkage between precipitation and recharge is still poorly understood in the Central America region. This study focuses on stable isotopic composition in precipitation and groundwater in the northern mountainous region of the Central Valley of Costa Rica. During the dry season, rainfall samples corresponded to enriched events with high deuterium excess. By mid-May, the Intertropical Convergence Zone poses over Costa Rica resulting in a depletion of 18 O/ 16 O and 2 H/H ratios. A parsimonious four-variable regression model (r 2  = 0.52) was able to predict daily δ 18 O in precipitation. Air mass back trajectories indicated a combination of Caribbean Sea and Pacific Ocean sources, which is clearly depicted in groundwater isoscape. Aquifers relying on Pacific-originated recharge exhibited a more depleted pattern, whereas recharge areas relying on Caribbean parental moisture showed an enrichment trend. These results can be used to enhance modelling efforts in Central America where scarcity of long-term data limits water resources management plans.

  16. Computer simulation of groundwater flow at a commercial radioactive-waste landfill near West Valley, Cattaraugus County, New York

    International Nuclear Information System (INIS)

    Prudic, D.E.

    1980-01-01

    Commercial low-level radioactive wastes were buried in trenches excavated in a clay-rich till of low hydraulic conductivity near West Valley, NY, from 1963 to 1975. Groundwater from the trenches flows out laterally and downward through approximately 25 m of till. A two-dimensional finite-element computer model was used to evaluate factors controlling groundwater flow is two vertical sections. Measured heads in 24 piezometers along these sections were most accurately reproduced by simulating four geologic units, each internally isotropic but differing in hydraulic conductivity to reflect fracturing near land surface and increased consolidation with depth. The model accurately simulated the changes in head that followed removal of water from one of the trenches. Specific-storage values required to calibrate the model for transient conditions agreed well with values derived from four consolidation tests of till samples. Infiltration rates ranging from 3.8 centimeters per year near swampy areas to 1.5 cm/y along scraped or smooth, sloping surfaces were used to simulate observed areal variation of head in the till. Simulations indicated that water flowing laterally out of trench would not intersect nearby intermittent streams as long as the water level in that trench remained below the trench cover

  17. Groundwater-quality data in the Western San Joaquin Valley study unit, 2010 - Results from the California GAMA Program

    Science.gov (United States)

    Mathany, Timothy M.; Landon, Matthew K.; Shelton, Jennifer L.; Belitz, Kenneth

    2013-01-01

    Groundwater quality in the approximately 2,170-square-mile Western San Joaquin Valley (WSJV) study unit was investigated by the U.S. Geological Survey (USGS) from March to July 2010, as part of the California State Water Resources Control Board (SWRCB) Groundwater Ambient Monitoring and Assessment (GAMA) Program's Priority Basin Project (PBP). The GAMA-PBP was developed in response to the California Groundwater Quality Monitoring Act of 2001 and is being conducted in collaboration with the SWRCB and Lawrence Livermore National Laboratory (LLNL). The WSJV study unit was the twenty-ninth study unit to be sampled as part of the GAMA-PBP. The GAMA Western San Joaquin Valley study was designed to provide a spatially unbiased assessment of untreated-groundwater quality in the primary aquifer system, and to facilitate statistically consistent comparisons of untreated groundwater quality throughout California. The primary aquifer system is defined as parts of aquifers corresponding to the perforation intervals of wells listed in the California Department of Public Health (CDPH) database for the WSJV study unit. Groundwater quality in the primary aquifer system may differ from the quality in the shallower or deeper water-bearing zones; shallow groundwater may be more vulnerable to surficial contamination. In the WSJV study unit, groundwater samples were collected from 58 wells in 2 study areas (Delta-Mendota subbasin and Westside subbasin) in Stanislaus, Merced, Madera, Fresno, and Kings Counties. Thirty-nine of the wells were selected by using a spatially distributed, randomized grid-based method to provide statistical representation of the study unit (grid wells), and 19 wells were selected to aid in the understanding of aquifer-system flow and related groundwater-quality issues (understanding wells). The groundwater samples were analyzed for organic constituents (volatile organic compounds [VOCs], low-level fumigants, and pesticides and pesticide degradates

  18. Regional oxygen reduction and denitrification rates in groundwater from multi-model residence time distributions, San Joaquin Valley, USA

    Science.gov (United States)

    Green, Christopher T.; Jurgens, Bryant; Zhang, Yong; Starn, Jeffrey; Singleton, Michael J.; Esser, Bradley K.

    2016-01-01

    Rates of oxygen and nitrate reduction are key factors in determining the chemical evolution of groundwater. Little is known about how these rates vary and covary in regional groundwater settings, as few studies have focused on regional datasets with multiple tracers and methods of analysis that account for effects of mixed residence times on apparent reaction rates. This study provides insight into the characteristics of residence times and rates of O2 reduction and denitrification (NO3− reduction) by comparing reaction rates using multi-model analytical residence time distributions (RTDs) applied to a data set of atmospheric tracers of groundwater age and geochemical data from 141 well samples in the Central Eastern San Joaquin Valley, CA. The RTD approach accounts for mixtures of residence times in a single sample to provide estimates of in-situ rates. Tracers included SF6, CFCs, 3H, He from 3H (tritiogenic He),14C, and terrigenic He. Parameter estimation and multi-model averaging were used to establish RTDs with lower error variances than those produced by individual RTD models. The set of multi-model RTDs was used in combination with NO3− and dissolved gas data to estimate zero order and first order rates of O2 reduction and denitrification. Results indicated that O2 reduction and denitrification rates followed approximately log-normal distributions. Rates of O2 and NO3− reduction were correlated and, on an electron milliequivalent basis, denitrification rates tended to exceed O2 reduction rates. Estimated historical NO3− trends were similar to historical measurements. Results show that the multi-model approach can improve estimation of age distributions, and that relatively easily measured O2 rates can provide information about trends in denitrification rates, which are more difficult to estimate.

  19. Riparian hydraulic gradient and stream-groundwater exchange dynamics in steep headwater valleys

    Science.gov (United States)

    T.J. Voltz; M.N. Gooseff; A.S. Ward; K. Singha; M. Fitzgerald; T. Wagener

    2013-01-01

    Patterns of riparian hydraulic gradients and stream-groundwater exchange in headwater catchments provide the hydrologic context for important ecological processes. Although the controls are relatively well understood, their dynamics during periods of hydrologic change is not. We investigate riparian hydraulic gradients over three different time scales in two steep,...

  20. Ground-Water Quality Data in the Southeast San Joaquin Valley, 2005-2006 - Results from the California GAMA Program

    Science.gov (United States)

    Burton, Carmen A.; Belitz, Kenneth

    2008-01-01

    Ground-water quality in the approximately 3,800 square-mile Southeast San Joaquin Valley study unit (SESJ) was investigated from October 2005 through February 2006 as part of the Priority Basin Assessment Project of Ground-Water Ambient Monitoring and Assessment (GAMA) Program. The GAMA Statewide Basin Assessment project was developed in response to the Ground-Water Quality Monitoring Act of 2001 and is being conducted by the California State Water Resources Control Board (SWRCB) in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory (LLNL). The SESJ study was designed to provide a spatially unbiased assessment of raw ground-water quality within SESJ, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from 99 wells in Fresno, Tulare, and Kings Counties, 83 of which were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study area (grid wells), and 16 of which were sampled to evaluate changes in water chemistry along ground-water flow paths or across alluvial fans (understanding wells). The ground-water samples were analyzed for a large number of synthetic organic constituents (volatile organic compounds [VOCs], pesticides and pesticide degradates, and pharmaceutical compounds), constituents of special interest (perchlorate, N-nitrosodimethylamine, and 1,2,3-trichloropropane), naturally occurring inorganic constituents (nutrients, major and minor ions, and trace elements), radioactive constituents, and microbial indicators. Naturally occurring isotopes (tritium, and carbon-14, and stable isotopes of hydrogen, oxygen, nitrogen, and carbon), and dissolved noble gases also were measured to help identify the source and age of the sampled ground water. Quality-control samples (blanks, replicates, samples for matrix spikes) were collected at approximately 10 percent of the wells, and the results

  1. Ground-Water Quality Data in the Southern Sacramento Valley, California, 2005 - Results from the California GAMA Program

    Science.gov (United States)

    Milby Dawson, Barbara J.; Bennett, George L.; Belitz, Kenneth

    2008-01-01

    Ground-water quality in the approximately 2,100 square-mile Southern Sacramento Valley study unit (SSACV) was investigated from March to June 2005 as part of the Statewide Basin Assessment Project of Ground-Water Ambient Monitoring and Assessment (GAMA) Program. This study was designed to provide a spatially unbiased assessment of raw ground-water quality within SSACV, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from 83 wells in Placer, Sacramento, Solano, Sutter, and Yolo Counties. Sixty-seven of the wells were selected using a randomized grid-based method to provide statistical representation of the study area. Sixteen of the wells were sampled to evaluate changes in water chemistry along ground-water flow paths. Four additional samples were collected at one of the wells to evaluate water-quality changes with depth. The GAMA Statewide Basin Assessment project was developed in response to the Ground-Water Quality Monitoring Act of 2001 and is being conducted by the California State Water Resources Control Board (SWRCB) in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory (LLNL). The ground-water samples were analyzed for a large number of man-made organic constituents (volatile organic compounds [VOCs], pesticides and pesticide degradates, pharmaceutical compounds, and wastewater-indicator constituents), constituents of special interest (perchlorate, N-nitrosodimethylamine [NDMA], and 1,2,3-trichloropropane [1,2,3-TCP]), naturally occurring inorganic constituents (nutrients, major and minor ions, and trace elements), radioactive constituents, and microbial indicators. Naturally occurring isotopes (tritium, and carbon-14, and stable isotopes of hydrogen, oxygen, and carbon), and dissolved noble gases also were measured to help identify the source and age of the sampled ground water. Quality-control samples (blanks, replicates, matrix spikes

  2. Bayesian Nitrate Source Apportionment to Individual Groundwater Wells in the Central Valley by use of Nitrogen, Oxygen, and Boron Isotopic Tracers

    Science.gov (United States)

    Lockhart, K.; Harter, T.; Grote, M.; Young, M. B.; Eppich, G.; Deinhart, A.; Wimpenny, J.; Yin, Q. Z.

    2014-12-01

    Groundwater quality is a concern in alluvial aquifers underlying agricultural areas worldwide, an example of which is the San Joaquin Valley, California. Nitrate from land applied fertilizers or from animal waste can leach to groundwater and contaminate drinking water resources. Dairy manure and synthetic fertilizers are the major sources of nitrate in groundwater in the San Joaquin Valley, however, septic waste can be a major source in some areas. As in other such regions around the world, the rural population in the San Joaquin Valley relies almost exclusively on shallow domestic wells (≤150 m deep), of which many have been affected by nitrate. Consumption of water containing nitrate above the drinking water limit has been linked to major health effects including low blood oxygen in infants and certain cancers. Knowledge of the proportion of each of the three main nitrate sources (manure, synthetic fertilizer, and septic waste) contributing to individual well nitrate can aid future regulatory decisions. Nitrogen, oxygen, and boron isotopes can be used as tracers to differentiate between the three main nitrate sources. Mixing models quantify the proportional contributions of sources to a mixture by using the concentration of conservative tracers within each source as a source signature. Deterministic mixing models are common, but do not allow for variability in the tracer source concentration or overlap of tracer concentrations between sources. Bayesian statistics used in conjunction with mixing models can incorporate variability in the source signature. We developed a Bayesian mixing model on a pilot network of 32 private domestic wells in the San Joaquin Valley for which nitrate as well as nitrogen, oxygen, and boron isotopes were measured. Probability distributions for nitrogen, oxygen, and boron isotope source signatures for manure, fertilizer, and septic waste were compiled from the literature and from a previous groundwater monitoring project on several

  3. Groundwater dependent pools in seasonal and permanent streams in the Clare Valley of South Australia

    Directory of Open Access Journals (Sweden)

    Erick Bestland

    2017-02-01

    In this Mediterranean climate with cool wet winters and dry hot summers strong salinity changes (up to 2.5 times due to seasonal cycles of wetting and drying were observed in surface water. Oxygen and hydrogen isotope values from pool sites showed strong evaporative enrichment during the dry season with up to 50% net evaporation calculated. Water isotopes from groundwater, however, cluster at the depleted end of the local meteoric water line and most do not show change despite significant seasonal salinity changes. Strontium isotope values and concentrations from the pools over the one year period do not define a mixing relationship. Instead, most pool sites have unchanging strontium isotope values despite the large seasonal change in salinity indicating strong evaporation of groundwater fed pools during this drought year.

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

    Siade, Adam; Nishikawa, Tracy; Martin, Peter

    2015-09-01

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

  6. A three-dimensional numerical model of predevelopment conditions in the Death Valley regional ground-water flow system, Nevada and California

    Energy Technology Data Exchange (ETDEWEB)

    D' Agnese, F.A.; O' Brien, G.M.; Faunt, C.C.; Belcher, W.R.; San Juan, Carma

    2002-11-22

    In the early 1990's, two numerical models of the Death Valley regional ground-water flow system were developed by the U.S. Department of Energy. In general, the two models were based on the same basic hydrogeologic data set. In 1998, the U.S. Department of Energy requested that the U.S. Geological Survey develop and maintain a ground-water flow model of the Death Valley region in support of U.S. Department of Energy programs at the Nevada Test Site. The purpose of developing this ''second-generation'' regional model was to enhance the knowledge and understanding of the ground-water flow system as new information and tools are developed. The U.S. Geological Survey also was encouraged by the U.S. Department of Energy to cooperate to the fullest extent with other Federal, State, and local entities in the region to take advantage of the benefits of their knowledge and expertise. The short-term objective of the Death Valley regional ground-water flow system project was to develop a steady-stat e representation of the predevelopment conditions of the ground-water flow system utilizing the two geologic interpretations used to develop the previous numerical models. The long-term objective of this project was to construct and calibrate a transient model that simulates the ground-water conditions of the study area over the historical record that utilizes a newly interpreted hydrogeologic conceptual model. This report describes the result of the predevelopment steady-state model construction and calibration.

  7. Groundwater quality monitoring well installation for Waste Area Groupings 8 and 9 at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    Mortimore, J.A.; Ebers, M.L.

    1994-09-01

    This report documents the drilling and installation of nine groundwater quality monitoring (GQM) wells on the perimeter of Waste Area Grouping (WAG) 8 and two GQM wells on the perimeter of WAG 9. WAG 8 encompasses approximately 34 acres, most of which are located in Melton Valley. Irregular in shape, the site has two sinuous extensions from its northern end that contain the low-level radioactive waste (LLW) transfer lines. WAG 8 contains 22 solid waste management units (SWMUs) that can be divided into 4 groups. These groups include the High Flux Isotope Reactor/Transuranium Processing Facility waste collection basins, the LLW line leak sites, and the active LLW tanks. WAG 9 encompasses about 3 acres and is located west of the main portion of WAG 8 and south of Melton Valley Drive. WAG 9 contains four SWMUs. The wells in WAGs 8 and 9 were drilled and developed from June 1989 to March 1990. Monitoring wells were installed to characterize and assess the WAGs in accordance with applicable Department of Energy, state, and Environmental Protection Agency regulatory requirements. The purpose of the well installation program was to install GQM wells for groundwater characterization at WAGs 8 and 9. Data packages produced during installation activities by the ERCE hydrogeologists are an important product of the program. These packages document the well drilling, installation, and development activities and provide valuable data for well sampling and WAG characterization. The forms contained in the packages include predrilling and postdrilling checklists, drilling and construction logs, development and hydraulic conductivity records, and quality control-related documents

  8. Status and understanding of groundwater quality in the Monterey Bay and Salinas Valley Basins, 2005-California GAMA Priority Basin Project

    Science.gov (United States)

    Kulongoski, Justin T.; Belitz, Kenneth

    2011-01-01

    Groundwater quality in the approximately 1,000 square mile (2,590 km2) Monterey Bay and Salinas Valley Basins (MS) study unit was investigated as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study unit is located in central California in Monterey, Santa Cruz, and San Luis Obispo Counties. The GAMA Priority Basin Project is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory. The GAMA MS study was designed to provide a spatially unbiased assessment of the quality of untreated (raw) groundwater in the primary aquifer systems (hereinafter referred to as primary aquifers). The assessment is based on water-quality and ancillary data collected in 2005 by the USGS from 97 wells and on water-quality data from the California Department of Public Health (CDPH) database. The primary aquifers were defined by the depth intervals of the wells listed in the CDPH database for the MS study unit. The quality of groundwater in the primary aquifers may be different from that in the shallower or deeper water-bearing zones; shallow groundwater may be more vulnerable to surficial contamination. The first component of this study, the status of the current quality of the groundwater resource, was assessed by using data from samples analyzed for volatile organic compounds (VOC), pesticides, and naturally occurring inorganic constituents, such as major ions and trace elements. This status assessment is intended to characterize the quality of groundwater resources in the primary aquifers of the MS study unit, not the treated drinking water delivered to consumers by water purveyors. Relative-concentrations (sample concentration divided by the health- or aesthetic-based benchmark concentration) were used for evaluating groundwater quality for those constituents that have Federal and (or) California regulatory or

  9. Ground-water flow and transport modeling of the NRC-licensed waste disposal facility, West Valley, New York

    International Nuclear Information System (INIS)

    Kool, J.B.; Wu, Y.S.

    1991-10-01

    This report describes a simulation study of groundwater flow and radionuclide transport from disposal at the NRC licensed waste disposal facility in West Valley, New York. A transient, precipitation driven, flow model of the near-surface fractured till layer and underlying unweathered till was developed and calibrated against observed inflow data into a recently constructed interceptor trench for the period March--May 1990. The results suggest that lateral flow through the upper, fractured till layer may be more significant than indicated by previous, steady state flow modeling studies. A conclusive assessment of the actual magnitude of lateral flow through the fractured till could however not be made. A primary factor contributing to this uncertainty is the unknown contribution of vertical infiltration through the interceptor trench cap to the total trench inflow. The second part of the investigation involved simulation of the migration of Sr-90, Cs-137 and Pu-239 from the one of the fuel hull disposal pits. A first-order radionuclide leach rate with rate coefficient of 10 -6 /day was assumed to describe radionuclide release into the disposal pit. The simulations indicated that for wastes buried below the fractured till zone, no significant migration would occur. However, under the assumed conditions, significant lateral migration could occur for radionuclides present in the upper, fractured till zone. 23 refs., 68 figs., 12 tabs

  10. Simulated effects of climate change on the Death Valley regional ground-water flow system, Nevada and California

    International Nuclear Information System (INIS)

    D'Agnese, F.A.; O'Brien, G.M.; Faunt, C.C.; San Juan, C.A.

    1999-01-01

    The US Geological Survey, in cooperation with the US Department of Energy, is evaluating the geologic and hydrologic characteristics of the Death Valley regional flow system as part of the Yucca Mountain Project. As part of the hydrologic investigation, regional, three-dimensional conceptual and numerical ground-water-flow models have been developed to assess the potential effects of past and future climates on the regional flow system. A simulation that is based on climatic conditions 21,000 years ago was evaluated by comparing the simulated results to observation of paleodischarge sites. Following acceptable simulation of a past climate, a possible future ground-water-flow system, with climatic conditions that represent a doubling of atmospheric carbon dioxide, was simulated. The steady-state simulations were based on the present-day, steady-state, regional ground-water-flow model. The finite-difference model consisted of 163 rows, 153 columns, and 3 layers and was simulated using MODFLOWP. Climate changes were implemented in the regional ground-water-flow model by changing the distribution of ground-water recharge. Global-scale, average-annual, simulated precipitation for both past- and future-climate conditions developed elsewhere were resampled to the model-grid resolution. A polynomial function that represents the Maxey-Eakin method for estimating recharge from precipitation was used to develop recharge distributions for simulation

  11. Comparison of Two AEM Groundwater Mineralisation Surveys in the Werra River Valley, Germany

    Science.gov (United States)

    Siemon, B.; Ullmann, A.; Vasterling, M.; Meyer, U.; Steuer, A.; Beer, W. W.; Pluemacher, J.

    2010-12-01

    The dissolution of Zechstein salt and the discharge of saltwater of the potash salt producing industry into the river Werra near the Hessian-Thuringian border in central Germany has led to a considerable mineralisation of ground and surface waters. In order to reduce the amount of saline water emissions directly into the river, the injection of waste water into the so called Plattendolomit was introduced. About 1000 million cubic meters have been stored in this porous and karstic limestone and dolomite bed of some ten metres thickness at about 500 meters depth. The waste water displaced the formation water upwards and in areas where fault zones exist saltwater rising occurred. Contracted by K+S KALI GmbH, BGR conducted a regional (1128 square kilometers) airborne geophysical survey in 2008 in addition to smaller survey (576 square kilometers) flown in 1996/97, both at 200/2000 meters line/tie-line spacing. Of particular interest was an area where a test disposal of saline waste water (9.5 million cubic meters) in the Gerstungen syncline took place between 1999 and 2007. Although complicated by the use of different helicopter-borne frequency-domain electromagnetic (HEM) systems (Dighem III and Resolve), it has been possible to quantitatively compare the results of both HEM surveys in order to map and outline changes of the near-surface groundwater mineralisation. Taking into account the challenging survey conditions, no significant increase in groundwater mineralisation could be substantiated within the achievable exploration depths of about 20 meters (saltwater ponds) and 200 meters (hard rock).

  12. Probability of Elevated Volatile Organic Compound (VOC) Concentrations in Groundwater in the Eagle River Watershed Valley-Fill Aquifer, Eagle County, North-Central Colorado, 2006-2007

    Science.gov (United States)

    Rupert, Michael G.; Plummer, Niel

    2009-01-01

    This raster data set delineates the predicted probability of elevated volatile organic compound (VOC) concentrations in groundwater in the Eagle River watershed valley-fill aquifer, Eagle County, North-Central Colorado, 2006-2007. This data set was developed by a cooperative project between the U.S. Geological Survey, Eagle County, the Eagle River Water and Sanitation District, the Town of Eagle, the Town of Gypsum, and the Upper Eagle Regional Water Authority. This project was designed to evaluate potential land-development effects on groundwater and surface-water resources so that informed land-use and water management decisions can be made. This groundwater probability map and its associated probability maps was developed as follows: (1) A point data set of wells with groundwater quality and groundwater age data was overlaid with thematic layers of anthropogenic (related to human activities) and hydrogeologic data by using a geographic information system to assign each well values for depth to groundwater, distance to major streams and canals, distance to gypsum beds, precipitation, soils, and well depth. These data then were downloaded to a statistical software package for analysis by logistic regression. (2) Statistical models predicting the probability of elevated nitrate concentrations, the probability of unmixed young water (using chlorofluorocarbon-11 concentrations and tritium activities), and the probability of elevated volatile organic compound concentrations were developed using logistic regression techniques. (3) The statistical models were entered into a GIS and the probability map was constructed.

  13. Probability of Elevated Nitrate Concentrations in Groundwater in the Eagle River Watershed Valley-Fill Aquifer, Eagle County, North-Central Colorado, 2006-2007

    Science.gov (United States)

    Rupert, Michael G.; Plummer, Niel

    2009-01-01

    This raster data set delineates the predicted probability of elevated nitrate concentrations in groundwater in the Eagle River watershed valley-fill aquifer, Eagle County, North-Central Colorado, 2006-2007. This data set was developed by a cooperative project between the U.S. Geological Survey, Eagle County, the Eagle River Water and Sanitation District, the Town of Eagle, the Town of Gypsum, and the Upper Eagle Regional Water Authority. This project was designed to evaluate potential land-development effects on groundwater and surface-water resources so that informed land-use and water management decisions can be made. This groundwater probability map and its associated probability maps was developed as follows: (1) A point data set of wells with groundwater quality and groundwater age data was overlaid with thematic layers of anthropogenic (related to human activities) and hydrogeologic data by using a geographic information system to assign each well values for depth to groundwater, distance to major streams and canals, distance to gypsum beds, precipitation, soils, and well depth. These data then were downloaded to a statistical software package for analysis by logistic regression. (2) Statistical models predicting the probability of elevated nitrate concentrations, the probability of unmixed young water (using chlorofluorocarbon-11 concentrations and tritium activities), and the probability of elevated volatile organic compound concentrations were developed using logistic regression techniques. (3) The statistical models were entered into a GIS and the probability map was constructed.

  14. Ground-Water Flow Model for the Spokane Valley-Rathdrum Prairie Aquifer, Spokane County, Washington, and Bonner and Kootenai Counties, Idaho

    Science.gov (United States)

    Hsieh, Paul A.; Barber, Michael E.; Contor, Bryce A.; Hossain, Md. Akram; Johnson, Gary S.; Jones, Joseph L.; Wylie, Allan H.

    2007-01-01

    This report presents a computer model of ground-water flow in the Spokane Valley-Rathdrum Prairie (SVRP) aquifer in Spokane County, Washington, and Bonner and Kootenai Counties, Idaho. The aquifer is the sole source of drinking water for more than 500,000 residents in the area. In response to the concerns about the impacts of increased ground-water withdrawals resulting from recent and projected urban growth, a comprehensive study was initiated by the Idaho Department of Water Resources, the Washington Department of Ecology, and the U.S. Geological Survey to improve the understanding of ground-water flow in the aquifer and of the interaction between ground water and surface water. The ground-water flow model presented in this report is one component of this comprehensive study. The primary purpose of the model is to serve as a tool for analyzing aquifer inflows and outflows, simulating the effects of future changes in ground-water withdrawals from the aquifer, and evaluating aquifer management strategies. The scale of the model and the level of detail are intended for analysis of aquifer-wide water-supply issues. The SVRP aquifer model was developed by the Modeling Team formed within the comprehensive study. The Modeling Team consisted of staff and personnel working under contract with the Idaho Department of Water Resources, personnel working under contract with the Washington Department of Ecology, and staff of the U.S. Geological Survey. To arrive at a final model that has the endorsement of all team members, decisions on modeling approach, methodology, assumptions, and interpretations were reached by consensus. The ground-water flow model MODFLOW-2000 was used to simulate ground-water flow in the SVPR aquifer. The finite-difference model grid consists of 172 rows, 256 columns, and 3 layers. Ground-water flow was simulated from September 1990 through September 2005 using 181 stress periods of 1 month each. The areal extent of the model encompasses an area of

  15. Questa Baseline and Pre-Mining Ground-Water Quality Investigation. 25. Summary of Results and Baseline and Pre-Mining Ground-Water Geochemistry, Red River Valley, Taos County, New Mexico, 2001-2005

    Science.gov (United States)

    Nordstrom, D. Kirk

    2008-01-01

    Active and inactive mine sites are challenging to remediate because of their complexity and scale. Regulations meant to achieve environmental restoration at mine sites are equally challenging to apply for the same reasons. The goal of environmental restoration should be to restore contaminated mine sites, as closely as possible, to pre-mining conditions. Metalliferous mine sites in the Western United States are commonly located in hydrothermally altered and mineralized terrain in which pre-mining concentrations of metals were already anomalously high. Typically, those pre-mining concentrations were not measured, but sometimes they can be reconstructed using scientific inference. Molycorp?s Questa molybdenum mine in the Red River Valley, northern New Mexico, is located near the margin of the Questa caldera in a highly mineralized region. The State of New Mexico requires that ground-water quality standards be met on closure unless it can be shown that potential contaminant concentrations were higher than the standards before mining. No ground water at the mine site had been chemically analyzed before mining. The aim of this investigation, in cooperation with the New Mexico Environment Department (NMED), is to infer the pre-mining ground-water quality by an examination of the geologic, hydrologic, and geochemical controls on ground-water quality in a nearby, or proximal, analog site in the Straight Creek drainage basin. Twenty-seven reports contain details of investigations on the geological, hydrological, and geochemical characteristics of the Red River Valley that are summarized in this report. These studies include mapping of surface mineralogy by Airborne Visible-Infrared Imaging Spectrometry (AVIRIS); compilations of historical surface- and ground- water quality data; synoptic/tracer studies with mass loading and temporal water-quality trends of the Red River; reaction-transport modeling of the Red River; environmental geology of the Red River Valley; lake

  16. Maps of the Bonsall area of the San Luis Rey River valley, San Diego County, California, showing geology, hydrology, and ground-water quality

    Science.gov (United States)

    Izbicki, John A.

    1985-01-01

    In November 1984, 84 wells and 1 spring in the Bonsall area of the San Luis Rey River valley were inventoried by U.S. Geological Survey personnel. Depth to water in 38 wells ranged from 1.3 to 38 ft and 23 wells had depths to water less than 10 feet. Dissolved solids concentration of water from 29 wells and 1 spring sampled in autumn 1983 and spring 1984 ranged from 574 to 2,370 mgs/L. Groundwater with a dissolved solids concentration less than 1,000 mgs/L was generally restricted to the eastern part of the aquifer. The total volume of alluvial fill in the Bonsall area is 113,000 acre-feet; the amount of groundwater storage available in the alluvial aquifer is 18,000 acre-feet. The alluvial aquifer is, in part, surrounded and underlain by colluvium and weathered crystalline rock that add some additional groundwater storage capacity to the system. Data in this report are presented on five maps showing well locations , thickness of alluvial fill, water level contours in November 1983 and hydrographs of selected wells, groundwater quality in spring 1960 and graphs showing changes in dissolved solids concentrations of water from selected wells with time, and groundwater quality in spring 1984. This report is part of a larger cooperative project between the Rainbow Municipal Irrigation District and the U.S. Geological Survey. The purpose of the larger project is to develop an appropriate groundwater management plan for the Bonsall area of the San Luis Rey River valley. (USGS)

  17. Groundwater Quality, Age, and Probability of Contamination, Eagle River Watershed Valley-Fill Aquifer, North-Central Colorado, 2006-2007

    Science.gov (United States)

    Rupert, Michael G.; Plummer, Niel

    2009-01-01

    The Eagle River watershed is located near the destination resort town of Vail, Colorado. The area has a fastgrowing permanent population, and the resort industry is rapidly expanding. A large percentage of the land undergoing development to support that growth overlies the Eagle River watershed valley-fill aquifer (ERWVFA), which likely has a high predisposition to groundwater contamination. As development continues, local organizations need tools to evaluate potential land-development effects on ground- and surface-water resources so that informed land-use and water management decisions can be made. To help develop these tools, the U.S. Geological Survey (USGS), in cooperation with Eagle County, the Eagle River Water and Sanitation District, the Town of Eagle, the Town of Gypsum, and the Upper Eagle Regional Water Authority, conducted a study in 2006-2007 of the groundwater quality, age, and probability of contamination in the ERWVFA, north-central Colorado. Ground- and surface-water quality samples were analyzed for major ions, nutrients, stable isotopes of hydrogen and oxygen in water, tritium, dissolved gases, chlorofluorocarbons (CFCs), and volatile organic compounds (VOCs) determined with very low-level laboratory methods. The major-ion data indicate that groundwaters in the ERWVFA can be classified into two major groups: groundwater that was recharged by infiltration of surface water, and groundwater that had less immediate recharge from surface water and had elevated sulfate concentrations. Sulfate concentrations exceeded the USEPA National Secondary Drinking Water Regulations (250 milligrams per liter) in many wells near Eagle, Gypsum, and Dotsero. The predominant source of sulfate to groundwater in the Eagle River watershed is the Eagle Valley Evaporite, which is a gypsum deposit of Pennsylvanian age located predominantly in the western one-half of Eagle County.

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

    Science.gov (United States)

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

    2012-01-01

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

  19. Simulated Ground-Water Withdrawals by Cabot WaterWorks from the Mississippi River Valley Alluvial Aquifer, Lonoke County, Arkansas

    Science.gov (United States)

    Czarnecki, John B.

    2007-01-01

    Cabot WaterWorks, located in Lonoke County, Arkansas, plans to increase ground-water withdrawals from the Mississippi River Valley alluvial aquifer from a 2004 rate of approximately 2.24 million gallons per day to between 4.8 and 8 million gallons per day by the end of 2049. The effects of increased pumping from several wells were simulated using a digital model of ground-water flow. The proposed additional withdrawals by Cabot WaterWorks were specified in three 1-square-mile model cells with increased pumping beginning in 2007. Increased pumping was specified at various combined rates for a period of 44 years. In addition, augmented pumping from wells owned by Grand Prairie Water Users Association, located about 2 miles from the nearest Cabot WaterWorks wells, was added to the model beginning in 2007 and continuing through to the end of 2049 in 10 of the 16 scenarios analyzed. Eight of the scenarios included reductions in pumping rates in model cells corresponding to either the Grand Prairie Water Users Association wells or to wells contained within the Grand Prairie Area Demonstration Project. Drawdown at the end of 44 years of pumping at 4.8 million gallons per day from the Cabot WaterWorks wells ranged from 15 to 25 feet in the three model cells; pumping at 8 million gallons per day resulted in water-level drawdown ranging from about 15 to 40 feet. Water levels in those cells showed no indication of leveling out at the end of the simulation period, indicating non-steady-state conditions after 44 years of pumping. From one to four new dry cells occurred in each of the scenarios by the end of 2049 when compared to a baseline scenario in which pumping was maintained at 2004 rates, even in scenarios with reduced pumping in the Grand Prairie Area Demonstration Project; however, reduced pumping produced cells that were no longer dry when compared to the baseline scenario at the end of 2049. Saturated thickness at the end of 2049 in the three Cabot WaterWorks wells

  20. Delineating the Drainage Structure and Sources of Groundwater Flux for Lake Basaka, Central Rift Valley Region of Ethiopia

    Directory of Open Access Journals (Sweden)

    Megersa Olumana Dinka

    2017-11-01

    Full Text Available As opposed to most of the other closed basin type rift valley lakes in Ethiopia, Lake Basaka is found to be expanding at an alarming rate. Different studies indicated that the expansion of the lake is challenging the socio-economics and environment of the region significantly. This study result and previous reports indicated that the lake’s expansion is mostly due to the increased groundwater (GW flux to the lake. GW flux accounts for about 56% of the total inflow in recent periods (post 2000 and is found to be the dominant factor for the hydrodynamics and existence of the lake. The analysis of the drainage network for the area indicates the existence of a huge recharge area on the western and upstream side of the catchment. This catchment has no surface outlet; hence most of the incoming surface runoff recharges the GW system. The recharge area is the main source of GW flux to the lake. In addition to this, the likely sources/causes of GW flux to the lake could be: (i an increase of GW recharge following the establishment of irrigation schemes in the region; (ii subsurface inflow from far away due to rift system influence, and (iii lake neotectonism. Overall, the lake’s expansion has damaging effect to the region, owing to its poor water quality; hence the identification of the real causes of GW flux and mitigation measures are very important for sustainable lake management. Therefore a comprehensive and detailed investigation of the parameters related to GW flux and the interaction of the lake with the GW system of the area is highly recommended.

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

    Science.gov (United States)

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

    2017-12-01

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

  2. Soil water storage and groundwater behaviour in a catenary sequence beneath forest in central Amazonia: I. Comparisons between plateau, slope and valley floor

    Directory of Open Access Journals (Sweden)

    M. G. Hodnett

    1997-01-01

    Full Text Available Soil water storage was monitored in three landscape elements in the forest (plateau, slope and valley floor over a 3 year period to identify differences in sub-surface hydrological response. Under the plateau and slope, the changes of storage were very similar and there was no indication of surface runoff on the slope. The mean maximum seasonal storage change was 156 mm in the 2 m profile but it was clear that, in the dry season, the forest was able to take up water from below 3.6 m. Soil water availability was low. Soil water storage changes in the valley were dominated by the behaviour of a shallow water table which, in normal years, varied between 0.1 m below the surface at the end of the wet season and 0.8 m at the end of the dry season. Soil water storage changes were small because root uptake was largely replenished by groundwater flow towards the stream. The groundwater behaviour is controlled mainly by the deep drainage from beneath the plateau and slope areas. The groundwater gradient beneath the slope indicated that recharge beneath the plateau and slope commences only after the soil water deficits from the previous dry season have been replenished. Following a wet season with little recharge, the water table fell, ceasing to influence the valley soil water storage, and the stream dried up. The plateau and slope, a zone of very high porosity between 0.4 and 1.1 m, underlain by a less conductive layer, is a probable route for interflow during, and for a few hours after, heavy and prolonged rainfall.

  3. Analyzing tree cores to detect petroleum hydrocarbon-contaminated groundwater at a former landfill site in the community of Happy Valley-Goose Bay, eastern Canadian subarctic

    DEFF Research Database (Denmark)

    Fonkwe, Merline L D; Trapp, Stefan

    2016-01-01

    Valley-Goose Bay, Labrador. Petroleum hydrocarbon contamination at the landfill site is the result of environmentally unsound pre-1990s disposal of households and industrial solid wastes. Tree cores were taken from trembling aspen, black spruce, and white birch and analyzed by headspace......-gas chromatography-mass spectrometry. BTEX compounds were detected in tree cores, corroborating known groundwater contamination. A zone of anomalously high concentrations of total BTEX constituents was identified and recommended for monitoring by groundwater wells. Tree cores collected outside the landfill site...... at a local control area suggest the migration of contaminants off-site. Tree species exhibit different concentrations of BTEX constituents, indicating selective uptake and accumulation. Toluene in wood exhibited the highest concentrations, which may also be due to endogenous production. Meanwhile, MTBE...

  4. Using remote sensing and GIS techniques to estimate discharge and recharge fluxes for the Death Valley regional groundwater flow system, USA

    Science.gov (United States)

    D'Agnese, F. A.; Faunt, C.C.; Turner, A.K.; ,

    1996-01-01

    The recharge and discharge components of the Death Valley regional groundwater flow system were defined by techniques that integrated disparate data types to develop a spatially complex representation of near-surface hydrological processes. Image classification methods were applied to multispectral satellite data to produce a vegetation map. The vegetation map was combined with ancillary data in a GIS to delineate different types of wetlands, phreatophytes and wet playa areas. Existing evapotranspiration-rate estimates were used to calculate discharge volumes for these area. An empirical method of groundwater recharge estimation was modified to incorporate data describing soil-moisture conditions, and a recharge potential map was produced. These discharge and recharge maps were readily converted to data arrays for numerical modelling codes. Inverse parameter estimation techniques also used these data to evaluate the reliability and sensitivity of estimated values.The recharge and discharge components of the Death Valley regional groundwater flow system were defined by remote sensing and GIS techniques that integrated disparate data types to develop a spatially complex representation of near-surface hydrological processes. Image classification methods were applied to multispectral satellite data to produce a vegetation map. This map provided a basis for subsequent evapotranspiration and infiltration estimations. The vegetation map was combined with ancillary data in a GIS to delineate different types of wetlands, phreatophytes and wet playa areas. Existing evapotranspiration-rate estimates were then used to calculate discharge volumes for these areas. A previously used empirical method of groundwater recharge estimation was modified by GIS methods to incorporate data describing soil-moisture conditions, and a recharge potential map was produced. These discharge and recharge maps were readily converted to data arrays for numerical modelling codes. Inverse parameter

  5. Treatability study on the Bear Creek Valley characterization area at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee. Phase II work plan for S-3 site contaminated groundwater interception--in-field media evaluation and groundwater capture methods

    International Nuclear Information System (INIS)

    1996-12-01

    A treatability study is being conducted to support implementation:of early actions at the S-3 Site in the Bear Creek Valley (BCV) Characterization Area (CA). The objectives of the early actions Will be (1) to reduce concentrations of uranium and nitrate in Bear Creek and (2) to reduce contaminants of concern in North Tributary (NT)-1 and NT-2. The BCV CA is located within the US DOE's Oak Ridge Reservation in Tennessee. Hazardous and radioactive materials from the Y-12 Plant operations were, disposed of at various sites within BCV. Groundwater and surface water in the BCV CA have been contaminated. The remedial investigation (RI) for the BCV CA identified that the greatest mass flux of contaminants from the various sources migrates via groundwater at the source and discharges to surface water in Bear Creek and its tributaries. In the RI, the combined discharge from the S-3 Site and the Boneyard/Burnyard (BYBY) was identified as accounting for 75% of the cancer risk and more than 80% of the chemical toxicity to Potential downgradient human receptors. In addition, the S-3 Site has caused degradation of surface water quality in upper Bear Creek and two of its tributaries. The BCV CA treatability study focuses on capture and treatment of shallow groundwater before it discharges to tributary waters. The objectives Of treatment of this groundwater are (1) to reduce the concentrations of uranium and nitrate in NT-1 and Bear Creek such that the concentrations of these chemicals in surface water and groundwater are reduced to acceptable levels, (2) to reduce the concentrations of nitrate and metals, and reduce the overall concentration of total dissolved solids; and (3) to hydraulically contain the plume of contaminated, groundwater that is moving in bedrock in the Nolichucky Shale such that the rate of contaminant discharge will be reduced in the long term. The objective of Phase II is to produce conceptual designs for treatment system configurations

  6. Chromium(VI) generation in vadose zone soils and alluvial sediments of the southwestern Sacramento Valley, California: a potential source of geogenic Cr(VI) to groundwater

    Science.gov (United States)

    Mills, Christopher T.; Morrison, Jean M.; Goldhaber, Martin B.; Ellefsen, Karl J.

    2011-01-01

    Concentrations of geogenic Cr(VI) in groundwater that exceed the World Health Organization’s maximum contaminant level for drinking water (50 μg L−1) occur in several locations globally. The major mechanism for mobilization of this Cr(VI) at these sites is the weathering of Cr(III) from ultramafic rocks and its subsequent oxidation on Mn oxides. This process may be occurring in the southern Sacramento Valley of California where Cr(VI) concentrations in groundwater can approach or exceed 50 μg L−1. To characterize Cr geochemistry in the area, samples from several soil auger cores (approximately 4 m deep) and drill cores (approximately 25 m deep) were analyzed for total concentrations of 44 major, minor and trace elements, Cr associated with labile Mn and Fe oxides, and Cr(VI). Total concentrations of Cr in these samples ranged from 140 to 2220 mg per kg soil. Between 9 and 70 mg per kg soil was released by selective extractions that target Fe oxides, but essentially no Cr was associated with the abundant reactive Mn oxides (up to ~1000 mg hydroxylamine-reducible Mn per kg soil was present). Both borehole magnetic susceptibility surveys performed at some of the drill core sites and relative differences between Cr released in a 4-acid digestion versus total Cr (lithium metaborate fusion digestion) suggest that the majority of total Cr in the samples is present in refractory chromite minerals transported from ultramafic exposures in the Coast Range Mountains. Chromium(VI) in the samples studied ranged from 0 to 42 μg kg−1, representing a minute fraction of total Cr. Chromium(VI) content was typically below detection in surface soils (top 10 cm) where soil organic matter was high, and increased with increasing depth in the soil auger cores as organic matter decreased. Maximum concentrations of Cr(VI) were up to 3 times greater in the deeper drill core samples than the shallow auger cores. Although Cr(VI) in these vadose zone soils and sediments was only a

  7. Contributions of Phosphorus from Groundwater to Streams in the Piedmont, Blue Ridge, and Valley and Ridge Physiographic Provinces, Eastern United States

    Science.gov (United States)

    Denver, Judith M.; Cravotta,, Charles A.; Ator, Scott W.; Lindsey, Bruce D.

    2011-01-01

    Phosphorus from natural and human sources is likely to be discharged from groundwater to streams in certain geochemical environments. Water-quality data collected from 1991 through 2007 in paired networks of groundwater and streams in different hydrogeologic and land-use settings of the Piedmont, Blue Ridge, and Valley and Ridge Physiographic Provinces in the eastern United States were compiled and analyzed to evaluate the sources, fate, and transport of phosphorus. The median concentrations of phosphate in groundwater from the crystalline and siliciclastic bedrock settings (0.017 and 0.020 milligrams per liter, respectively) generally were greater than the median for the carbonate setting (less than 0.01 milligrams per liter). In contrast, the median concentrations of dissolved phosphate in stream base flow from the crystalline and siliciclastic bedrock settings (0.010 and 0.014 milligrams per liter, respectively) were less than the median concentration for base-flow samples from the carbonate setting (0.020 milligrams per liter). Concentrations of phosphorus in many of the stream base-flow and groundwater samples exceeded ecological criteria for streams in the region. Mineral dissolution was identified as the dominant source of phosphorus in the groundwater and stream base flow draining crystalline or siliciclastic bedrock in the study area. Low concentrations of dissolved phosphorus in groundwater from carbonate bedrock result from the precipitation of minerals and (or) from sorption to mineral surfaces along groundwater flow paths. Phosphorus concentrations are commonly elevated in stream base flow in areas underlain by carbonate bedrock, however, presumably derived from in-stream sources or from upland anthropogenic sources and transported along short, shallow groundwater flow paths. Dissolved phosphate concentrations in groundwater were correlated positively with concentrations of silica and sodium, and negatively with alkalinity and concentrations of calcium

  8. Groundwater-quality data in the Bear Valley and Selected Hard Rock Areas study unit, 2010: Results from the California GAMA Program

    Science.gov (United States)

    Mathany, Timothy M.; Belitz, Kenneth

    2013-01-01

    Groundwater quality in the 112-square-mile Bear Valley and Selected Hard Rock Areas (BEAR) study unit was investigated by the U.S. Geological Survey (USGS) from April to August 2010, as part of the California State Water Resources Control Board (SWRCB) Groundwater Ambient Monitoring and Assessment (GAMA) Program’s Priority Basin Project (PBP). The GAMA-PBP was developed in response to the California Groundwater Quality Monitoring Act of 2001 and is being conducted in collaboration with the SWRCB and Lawrence Livermore National Laboratory (LLNL). The BEAR study unit was the thirty-first study unit to be sampled as part of the GAMA-PBP. The GAMA Bear Valley and Selected Hard Rock Areas study was designed to provide a spatially unbiased assessment of untreated-groundwater quality in the primary aquifer system and to facilitate statistically consistent comparisons of untreated groundwater quality throughout California. The primary aquifer system is defined as the zones corresponding to the perforation intervals of wells listed in the California Department of Public Health (CDPH) database for the BEAR study unit. Groundwater quality in the primary aquifer system may differ from the quality in the shallow or deep water-bearing zones; shallow groundwater may be more vulnerable to surficial contamination. In the BEAR study unit, groundwater samples were collected from two study areas (Bear Valley and Selected Hard Rock Areas) in San Bernardino County. Of the 38 sampling sites, 27 were selected by using a spatially distributed, randomized grid-based method to provide statistical representation of the primary aquifer system in the study unit (grid sites), and the remaining 11 sites were selected to aid in the understanding of the potential groundwater-quality issues associated with septic tank use and with ski areas in the study unit (understanding sites). The groundwater samples were analyzed for organic constituents (volatile organic compounds [VOCs], pesticides and

  9. Using a Three-Dimensional Hydrogeologic Framework to Investigate Potential Sources of Water Springs in the Death Valley Regional Groundwater Flow System

    Science.gov (United States)

    Hill, M. C.; Belcher, W. R.; Sweetkind, D. S.; Faunt, C.

    2014-12-01

    The Death Valley regional groundwater flow system encompasses a proposed site for a high-level nuclear waste repository of the United States of America, the Nevada National Security Site (NNSS), where nuclear weapons were tested, and National Park and BLM properties, and provides water for local communities. The model was constructed using a three-dimensional hydrogeologic framework and has been used as a resource planning mechanism by the many stakeholders involved, including four United States (U.S) federal agencies (U.S. Department of Energy, National Park Service, Bureau of Land Management, and U.S. Fish and Wildlife Service) and local counties, towns, and residents. One of the issues in recent model development is simulation of insufficient water to regional discharge areas which form springs in valleys near the center of the system. Given what seems to be likely rock characteristics and geometries at depth, insufficient water is simulated to reach the discharge areas. This "surprise" thus challenges preconceived notions about the system. Here we use the hydrogeologic model to hypothesize alternatives able to produce the observed flow and use the groundwater simulation to test the hypotheses with other available data. Results suggest that the transmissivity measurements need to be used carefully because wells in this system are never fully penetrating, that multiple alternatives are able to produce the springflow, and that one most likely alternative cannot be identified given available data. Consequences of the alternatives are discussed.

  10. Comparison of alternative representations of hydraulic-conductivity anisotropy in folded fractured-sedimentary rock: Modeling groundwater flow in the Shenandoah Valley (USA)

    Science.gov (United States)

    Yager, R.M.; Voss, C.I.; Southworth, S.

    2009-01-01

    A numerical representation that explicitly represents the generalized three-dimensional anisotropy of folded fractured-sedimentary rocks in a groundwater model best reproduces the salient features of the flow system in the Shenandoah Valley, USA. This conclusion results from a comparison of four alternative representations of anisotropy in which the hydraulic-conductivity tensor represents the bedrock structure as (model A) anisotropic with variable strikes and dips, (model B) horizontally anisotropic with a uniform strike, (model C) horizontally anisotropic with variable strikes, and (model D) isotropic. Simulations using the US Geological Survey groundwater flow and transport model SUTRA are based on a representation of hydraulic conductivity that conforms to bedding planes in a three-dimensional structural model of the valley that duplicates the pattern of folded sedimentary rocks. In the most general representation, (model A), the directions of maximum and medium hydraulic conductivity conform to the strike and dip of bedding, respectively, while the minimum hydraulic-conductivity direction is perpendicular to bedding. Model A produced a physically realistic flow system that reflects the underlying bedrock structure, with a flow field that is significantly different from those produced by the other three models. ?? Springer-Verlag 2009.

  11. Natural methane occurrence in domestic wells is common in sodium-rich shallow groundwater in valley settings overlying the Marcellus Shale

    Science.gov (United States)

    Lautz, L.; Christian, K.; Hoke, G. D.; Siegel, D. I.; Lu, Z.; Kessler, J. D.

    2015-12-01

    Unconventional gas production from the Marcellus shale has proliferated in the past decade, raising concerns regarding impacts on fresh groundwater resources. Methane contamination of shallow groundwater can result from faulty seals on gas production wells or migration of methane along fractures during well development. Characterizing such contamination is of particular concern in the rural Marcellus shale region, where the water supply is primarily private, domestic wells and methane occurs naturally in shallow groundwater. High volume hydraulic fracturing (HVHF) is currently used to produce gas in all states overlying the Marcellus shale, with the exception of New York (NY), where HVHF is permanently banned. Given the similar regional geology, climate, and land use across areas underlain by the Marcellus, studies of methane occurrence in domestic wells in NY are representative of methane occurrence prior to HVHF in an area with conventional gas production. We measured methane concentrations in 137 domestic wells across 5 counties in southern NY covering an area of 10,230 km2. For each well, we determined the topographic position (valley or upland), the geologic unit of water extraction, the chemical water type, and distances to the nearest fault, lineament, and active or other conventional gas well. Methane concentrations in domestic wells were not significantly different between geologic units of extraction, nor did they correlate with distances to faults, lineaments, or gas wells. Methane concentrations did differ between valleys and uplands, but the significance of such differences varied based on the method of classification. Methane concentrations were significantly different between water types; Na-HCO3 waters had significantly higher methane concentrations than Ca-HCO3 waters (median values of 0.78 and 0.002 mg/L, respectively). Combining methane and water quality data from this study and other prior studies in NY and Pennsylvania (n=724), we found that

  12. Status and understanding of groundwater quality in the Bear Valley and Lake Arrowhead Watershed Study Unit, 2010: California GAMA Priority Basin Project

    Science.gov (United States)

    Mathany, Timothy; Burton, Carmen

    2017-06-20

    Groundwater quality in the 112-square-mile Bear Valley and Lake Arrowhead Watershed (BEAR) study unit was investigated as part of the Priority Basin Project (PBP) of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study unit comprises two study areas (Bear Valley and Lake Arrowhead Watershed) in southern California in San Bernardino County. The GAMA-PBP is conducted by the California State Water Resources Control Board (SWRCB) in cooperation with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory.The GAMA BEAR study was designed to provide a spatially balanced, robust assessment of the quality of untreated (raw) groundwater from the primary aquifer systems in the two study areas of the BEAR study unit. The assessment is based on water-quality collected by the USGS from 38 sites (27 grid and 11 understanding) during 2010 and on water-quality data from the SWRCB-Division of Drinking Water (DDW) database. The primary aquifer system is defined by springs and the perforation intervals of wells listed in the SWRCB-DDW water-quality database for the BEAR study unit.This study included two types of assessments: (1) a status assessment, which characterized the status of the quality of the groundwater resource as of 2010 by using data from samples analyzed for volatile organic compounds, pesticides, and naturally present inorganic constituents, such as major ions and trace elements, and (2) an understanding assessment, which evaluated the natural and human factors potentially affecting the groundwater quality. The assessments were intended to characterize the quality of groundwater resources in the primary aquifer system of the BEAR study unit, not the treated drinking water delivered to consumers. Bear Valley study area and the Lake Arrowhead Watershed study area were also compared statistically on the basis of water-quality results and factors potentially affecting the groundwater quality.Relative concentrations (RCs

  13. Impacts of future changes on groundwater recharge and flow in highly-connected river-aquifer systems: A case study of the Spokane Valley-Rathdrum Prairie Aquifer

    Science.gov (United States)

    Nguyen, T. T.; Baxter, H.; Barber, M. E.; Hossain, A.; Orr, C. H.; Adam, J. C.

    2013-12-01

    The Spokane, Washington-Coeur d'Alene, Idaho Corridor is well-known for its Spokane Valley-Rathdrum Prairie (SVRP) Aquifer which is a sole source of drinking water for more than 500,000 people. The aquifer is highly connected to the Spokane River and responds very fast to natural and human perturbations, making it relatively vulnerable to climate and anthropogenic changes in future decades. Recent studies have indicated a decline in minimum daily flow in the Spokane River in the last 100 years, while projecting an increase in cool-season precipitation into the future. We investigated the potential impacts of these projected future climate-driven hydrologic changes on groundwater recharge and flow in the SVRP. A distributed, physically-based hydrological model, the Precipitation Runoff Modeling System (PRMS), was coupled with an existing Modular three-dimensional finite-difference ground-water model (MODFLOW) to have better estimates of recharge into the SVRP as well as the interaction of surface water and groundwater. The couple model was calibrated and validated at a daily time-step within the Model-Independent Parameter Estimation (PEST) framework using 16 years of both observed streamflow and observed well data (1990 - 2005). To assess future climate change impacts, statistically downscaled climate projections of temperature and precipitation between 2010 and 2050 from four general circulation models were used. The results from the coupled model provide insight on the interplay between snowmelt, streamflow, groundwater recharge and discharge in such a highly-connected system. Moreover, the relative sensitivities of groundwater recharge and flow with respect to changes in climate and land cover are also examined. These results can be used as good references for long term water resources management and planning in the region.

  14. A new concept of irrigation response units for effective management of surface and groundwater resources: a case study from the multi-country Fergana Valley, Central Asia

    KAUST Repository

    Awan, Usman Khalid

    2016-09-09

    When estimating canal water supplies for large-scale irrigation schemes and especially in arid regions worldwide, the impact of all factors affecting the gross irrigation requirements (GIR) are not properly accounted for, which results in inefficient use of precious freshwater resources. This research shows that the concept of irrigation response units (IRU)—areas having unique combinations of factors effecting the GIR—allows for more precise estimates of GIR. An overlay analysis of soil texture and salinity, depth and salinity of groundwater, cropping patterns and irrigation methods was performed in a GIS environment, which yielded a total of 17 IRUs combinations of the Oktepa Zilol Chashmasi water consumers’ association in multi-country Fergana Valley, Central Asia. Groundwater contribution, leaching requirements, losses in the irrigation system through field application and conveyance and effective rainfall were included in GIR estimates. The GIR varied significantly among IRUs [average of 851 mm (±143 mm)] with a maximum (1051 mm) in IRU-12 and a minimum (629 mm) in IRUs-15, 16. Owing to varying groundwater levels in each IRU, the groundwater contribution played a key role in the estimation of the GIR. The maximum groundwater contribution occurred in IRUs dominated by cotton–fallow rotations as evidenced by an average value of 159 mm but a maximum of 254 mm and a minimum of 97 mm. Percolation losses depended on irrigation methods for different crops in their respective IRUs. The novel approach can guide water managers in this and similar regions to increase the accuracy of irrigation demands based on all the factor effecting the GIR. © 2016 Springer-Verlag Berlin Heidelberg

  15. A multi-isotope (B, Sr, O, H) and age dating (3H-3He, 14C) study of groundwater from Salinas Valley, California

    International Nuclear Information System (INIS)

    Vengosh, A.; Gill, J.; Davisson, M.L.; Hudson, G.B.

    1999-01-01

    This study investigates the chemical and isotopic compositions of groundwater from Salinas Valley, California in order to constrain the origin and rates of groundwater contamination. We use an array of geochemical, environmental isotopes of water ( 18 O/ 16 O, D/H, 3 H- 3 He) and dissolved salts ( 11 B/ 10 B, 87 Sr/ 86 Sr, 14 C) to establish a reliable conceptual model for the basin. The basin consists of a deep, confined '400-foot aquifer' overlying the '180-foot aquifer' and a perched aquifer, all made up of sand, gravels, clays, and alluvial deposits. Our 3 H- 3 He, 14 C, and δ 18 O results show different replenishment zones and rates in the basin: (1) rapid replenishment ( 14 C concentrations of 72 to 98 pmc) in the perched and 180-foot aquifers in the northern area; (2) fast arrival (15 years) of 18 O- and NO 3 -enriched agriculture-return flows in the unconfined 180-foot aquifer in the central valley; (3) young water recharge (6 to 20 years) fi-om the Salinas River, which is enriched in 18 O and D relative to GMWL, occurs in the southern basin; and (4) travel time of >10,000 years ( 14 C = 21.3 PMC) in the deep 400-foot aquifer in the northern area of the valley, indicating pristine slow recharge. We identified several different end-member saline components with distinguishable chemical and isotopic fingerprints: (1) agriculture return flow in the perched aquifer (e.g., high NO 3 and SO 4 , low 87 Sr/ 86 Sr 0.7082, δ 11 B = 19 per mille); (2) salt-water intrusion in the northern basin (e.g., low Na/Cl, marine Br/Cl, high Ca/Mg, δ 11 B = 17 to 38 per mille, 87 Sr/ 86 Sr = 0.7088 to 0.7096; (3) non-marine saline water in the southern part of the valley (e.g., high SO 4 , high Na/Cl, δ 11 B = 24 to 30 per mille, 87 Sr/ 86 Sr = 0.70852). The geochemical and isotopic fingerprints of the different water sources enables us to delineate the impact of these sources in different areas of the valley as well as to evaluate the origin of the saline, Sod-enriched plume

  16. Combined cGPS and InSAR time series for observing subsidence in the southern Central Valley due to groundwater exploitation

    Science.gov (United States)

    Neely, W.; Borsa, A. A.; Silverii, F.

    2017-12-01

    Recent droughts have increased reliance on groundwater for agricultural production in California's Central Valley. Using Interferometric Synthetic Aperture Radar (InSAR), we observe upwards of 25 cm/yr of subsidence from November 2014 to February 2017 due to intense pumping. However, these observations are contaminated by atmospheric noise and orbital errors. We present a novel method for correcting long wavelength errors in InSAR deformation estimates using time series from continuous Global Positioning System (cGPS) stations within the SAR footprint, which we apply to C-band data from the Sentinel mission. We test our method using 49 SAR acquisitions from the Sentinel 1 satellites and 107 cGPS times series from the Geodesy Advancing Geoscience and EarthScope (GAGE) network in southern Central Valley. We correct each interferogram separately, implementing an intermittent Small Baseline Subset (ISBAS) technique to produce a time series of line-of-sight surface motion from 276 InSAR pairs. To estimate the vertical component of this motion, we remove horizontal tectonic displacements predicted by the Southern California Earthquake Center's (SCEC) Community Geodetic Model. We validate our method by comparing the corrected InSAR results with independent cGPS data and find a marked improvement in agreement between the two data sets, particularly in the deformation rates. Using this technique, we characterize the time evolution of surface vertical deformation in the southern Central Valley related to human exploitation of local groundwater resources. This methodology is applicable to data from other SAR satellites, including ALOS-2 and the upcoming US-India NISAR mission.

  17. Groundwater-level analysis of selected wells in the Hoosic River Valley near Hoosick Falls, New York, for aquifer framework and properties

    Science.gov (United States)

    Williams, John H.; Heisig, Paul M.

    2018-03-05

    The U.S. Geological Survey, in cooperation with the New York State Department of Environmental Conservation, analyzed groundwater levels, drilling record logs, and field water-quality data from selected wells, and the surficial geology in the Hoosic River valley south of the village of Hoosick Falls, New York, to provide information about the framework and properties of a confined aquifer. The aquifer, which consists of ice-contact sand and gravel overlain by lacustrine clay and silt, was evaluated by the New York State Department of Environmental Conservation as part of their investigation of alternate water supplies for the village whose wellfield has been affected by perfluorooctanoic acid. Wells inventoried in the study area were classified as confined, water table, or transitional between the two aquifer conditions. Groundwater levels in three confined-aquifer wells and a transitional-aquifer well responded to pumping of a test production well finished in the confined aquifer. Groundwater levels in a water-table well showed no detectable water-level change in response to test-well pumping. Analysis of drawdown and recovery data from the three confined-aquifer wells and a transitional-aquifer well through the application of the Theis type-curve method provided estimates of aquifer properties. Representation of a constant-head boundary in the analysis where an unnamed pond and fluvial-terrace deposits abut the valley wall resulted in satisfactory matches of the Theis type curves with the observed water-level responses. Aquifer transmissivity estimates ranged from 1,160 to 1,370 feet squared per day. Aquifer storativity estimates ranged from 5.2×10–5 to 1.1×10–3 and were consistent with the inferred degree of confinement and distance from the represented recharge boundary.

  18. Ground-Water Quality Data in the Monterey Bay and Salinas Valley Basins, California, 2005 - Results from the California GAMA Program

    Science.gov (United States)

    Kulongoski, Justin T.; Belitz, Kenneth

    2007-01-01

    Ground-water quality in the approximately 1,000-square-mile Monterey Bay and Salinas Valley study unit was investigated from July through October 2005 as part of the California Ground-Water Ambient Monitoring and Assessment (GAMA) program. The study was designed to provide a spatially unbiased assessment of raw ground-water quality, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from 94 public-supply wells and 3 monitoring wells in Monterey, Santa Cruz, and San Luis Obispo Counties. Ninety-one of the public-supply wells sampled were selected to provide a spatially distributed, randomized monitoring network for statistical representation of the study area. Six wells were sampled to evaluate changes in water chemistry: three wells along a ground-water flow path were sampled to evaluate lateral changes, and three wells at discrete depths from land surface were sampled to evaluate changes in water chemistry with depth from land surface. The ground-water samples were analyzed for volatile organic compounds (VOCs), pesticides, pesticide degradates, nutrients, major and minor ions, trace elements, radioactivity, microbial indicators, and dissolved noble gases (the last in collaboration with Lawrence Livermore National Laboratory). Naturally occurring isotopes (tritium, carbon-14, helium-4, and the isotopic composition of oxygen and hydrogen) also were measured to help identify the source and age of the sampled ground water. In total, 270 constituents and water-quality indicators were investigated for this study. This study did not attempt to evaluate the quality of water delivered to consumers; after withdrawal from the ground, water typically is treated, disinfected, and (or) blended with other waters to maintain water quality. In addition, regulatory thresholds apply to treated water that is served to the consumer, not to raw ground water. In this study, only six constituents, alpha radioactivity, N

  19. Trends in nitrate concentrations and determination of its origin using stable isotopes (18O and 15N) in groundwater of the Western Central Valley, Costa Rica.

    Science.gov (United States)

    Reynolds-Vargas, Jenny; Fraile-Merino, Julio; Hirata, Ricardo

    2006-08-01

    A study was conducted to evaluate long-term trends in nitrate concentrations and to try to identify the origin of nitrate using stable isotopes (15N(NO3-) and 18O(NO3-)) in the aquifers of the western Central Valley, Costa Rica, where more than 1 million people depend on groundwater to satisfy their daily needs. Data from 20 sites periodically sampled for 4 to 17 years indicate an increasing trend in nitrate concentrations at five sites, which in a period ranging from 10 to 40 years, will exceed recommended maximum concentrations. Results of isotopic analysis indicate a correspondence between land use patterns and the isotopic signature of nitrate in groundwater and suggest that urbanization processes without adequate waste disposal systems, followed by coffee fertilization practices, are threatening water quality in the region. We conclude that groundwater management in this area is not sustainable, and that land use substitution processes from agricultural activity to residential occupation that do not have proper sewage disposal systems may cause a significant increment in the nitrate contaminant load.

  20. Remedial Investigation work plan for Bear Creek Valley Operable Unit 4 (shallow groundwater in Bear Creek Valley) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    1993-09-01

    To effectively evaluate the cumulative impact of releases from multiple sources of contamination, a structured approach has been adopted for Oak Ridge Reservation (ORR) based on studies of the groundwater and surface water separate from studies of the sources. Based on the realization of the complexity of the hydrogeologic regime of the ORR, together with the fact that there are numerous sources contributing to groundwater contamination within a geographical area, it was agreed that more timely investigations, at perhaps less cost, could be achieved by separating the sources of contamination from the groundwater and surface water for investigation and remediation. The result will be more immediate attention [Records of Decision (RODS) for interim measures or removal actions] for the source Operable Units (OUs) while longer-term remediation investigations continue for the hydrogeologic regime's, which are labeled as integrator OUs. This Remedial Investigation work plan contains summaries of geographical, historical, operational, geological, and hydrological information specific to the unit. Taking advantage of the historical data base and ongoing monitoring activities and applying the observational approach to focus data gathering activities will allow the Feasibility Study to evaluate all probable or likely alternatives

  1. Remedial investigation work plan for Bear Creek Valley Operable Unit 4 (shallow groundwater in Bear Creek Valley) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    1993-07-01

    To effectively evaluate the cumulative impact of releases from multiple sources of contamination, a structured approach has been adopted for Oak Ridge Reservation (ORR) based on studies of the groundwater and surface water separate from studies of the sources. Based on the realization of the complexity of the hydrogeologic regime of the ORR, together with the fact that there are numerous sources contributing to groundwater contamination within a geographical area, it was agreed that more timely investigations, at perhaps less cost, could be achieved by separating the sources of contamination from the groundwater and surface water for investigation and remediation. The result will be more immediate attention [Records of Decision (RODs) for interim measures or removal actions] for the source Operable Units (OUs) while longer-term remediation investigations continue for the hydrogeologic regimes, which are labeled as integrator OUs. This remedial investigation work plan contains summaries of geographical, historical, operational, geological, and hydrological information specific to the unit. Taking advantage of the historical data base and ongoing monitoring activities and applying the observational approach to focus data gathering activities will allow the feasibility study to evaluate all probable or likely alternatives.

  2. Remedial Investigation work plan for Bear Creek Valley Operable Unit 4 (shallow groundwater in Bear Creek Valley) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    1993-09-01

    To effectively evaluate the cumulative impact of releases from multiple sources of contamination, a structured approach has been adopted for Oak Ridge Reservation (ORR) based on studies of the groundwater and surface water separate from studies of the sources. Based on the realization of the complexity of the hydrogeologic regime of the ORR, together with the fact that there are numerous sources contributing to groundwater contamination within a geographical area, it was agreed that more timely investigations, at perhaps less cost, could be achieved by separating the sources of contamination from the groundwater and surface water for investigation and remediation. The result will be more immediate attention [Records of Decision (RODS) for interim measures or removal actions] for the source Operable Units (OUs) while longer-term remediation investigations continue for the hydrogeologic regime`s, which are labeled as integrator OUs. This Remedial Investigation work plan contains summaries of geographical, historical, operational, geological, and hydrological information specific to the unit. Taking advantage of the historical data base and ongoing monitoring activities and applying the observational approach to focus data gathering activities will allow the Feasibility Study to evaluate all probable or likely alternatives.

  3. Remedial investigation work plan for Bear Creek Valley Operable Unit 4 (shallow groundwater in Bear Creek Valley) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    1993-07-01

    To effectively evaluate the cumulative impact of releases from multiple sources of contamination, a structured approach has been adopted for Oak Ridge Reservation (ORR) based on studies of the groundwater and surface water separate from studies of the sources. Based on the realization of the complexity of the hydrogeologic regime of the ORR, together with the fact that there are numerous sources contributing to groundwater contamination within a geographical area, it was agreed that more timely investigations, at perhaps less cost, could be achieved by separating the sources of contamination from the groundwater and surface water for investigation and remediation. The result will be more immediate attention [Records of Decision (RODs) for interim measures or removal actions] for the source Operable Units (OUs) while longer-term remediation investigations continue for the hydrogeologic regimes, which are labeled as integrator OUs. This remedial investigation work plan contains summaries of geographical, historical, operational, geological, and hydrological information specific to the unit. Taking advantage of the historical data base and ongoing monitoring activities and applying the observational approach to focus data gathering activities will allow the feasibility study to evaluate all probable or likely alternatives

  4. Questa baseline and pre-mining ground-water quality investigation. 14. Interpretation of ground-water geochemistry in catchments other than the Straight Creek catchment, Red River Valley, Taos County, New Mexico, 2002-2003

    Science.gov (United States)

    Nordstrom, D. Kirk; McCleskey, R. Blaine; Hunt, Andrew G.; Naus, Cheryl A.

    2005-01-01

    The U.S. Geological Survey, in cooperation with the New Mexico Environment Department, is investigating the pre-mining ground-water chemistry at the Molycorp molybdenum mine in the Red River Valley, New Mexico. The primary approach is to determine the processes controlling ground-water chemistry at an unmined, off-site but proximal analog. The Straight Creek catchment, chosen for this purpose, consists of the same Tertiary-age quartz-sericite-pyrite altered andesite and rhyolitic volcanics as the mine site. Straight Creek is about 5 kilometers east of the eastern boundary of the mine site. Both Straight Creek and the mine site are at approximately the same altitude, face south, and have the same climatic conditions. Thirteen wells in the proximal analog drainage catchment were sampled for ground-water chemistry. Eleven wells were installed for this study and two existing wells at the Advanced Waste-Water Treatment (AWWT) facility were included in this study. Eight wells were sampled outside the Straight Creek catchment: one each in the Hansen, Hottentot, and La Bobita debris fans, four in a well cluster in upper Capulin Canyon (three in alluvial deposits and one in bedrock), and an existing well at the U.S. Forest Service Questa Ranger Station in Red River alluvial deposits. Two surface waters from the Hansen Creek catchment and two from the Hottentot drainage catchment also were sampled for comparison to ground-water compositions. In this report, these samples are evaluated to determine if the geochemical interpretations from the Straight Creek ground-water geochemistry could be extended to other ground waters in the Red River Valley , including the mine site. Total-recoverable major cations and trace metals and dissolved major cations, selected trace metals, anions, alkalinity; and iron-redox species were determined for all surface- and ground-water samples. Rare-earth elements and low-level As, Bi, Mo, Rb, Re, Sb, Se, Te, Th, U, Tl, V, W, Y, and Zr were

  5. Status and understanding of groundwater quality in the two southern San Joaquin Valley study units, 2005-2006 - California GAMA Priority Basin Project

    Science.gov (United States)

    Burton, Carmen A.; Shelton, Jennifer L.; Belitz, Kenneth

    2012-01-01

    Groundwater quality in the southern San Joaquin Valley was investigated from October 2005 through March 2006 as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Project is conducted by the U.S. Geological Survey (USGS) in collaboration with the California State Water Resources Control Board and the Lawrence Livermore National Laboratory. There are two study units located in the southern San Joaquin Valley: the Southeast San Joaquin Valley (SESJ) study unit and the Kern County Subbasin (KERN) study unit. The GAMA Priority Basin Project in the SESJ and KERN study units was designed to provide a statistically unbiased, spatially distributed assessment of untreated groundwater quality within the primary aquifers. The status assessment is based on water-quality and ancillary data collected in 2005 and 2006 by the USGS from 130 wells on a spatially distributed grid, and water-quality data from the California Department of Public Health (CDPH) database. Data was collected from an additional 19 wells for the understanding assessment. The aquifer systems (hereinafter referred to as primary aquifers) were defined as that part of the aquifer corresponding to the perforation interval of wells listed in the CDPH database for the SESJ and KERN study units. The status assessment of groundwater quality used data from samples analyzed for anthropogenic constituents such as volatile organic compounds (VOCs) and pesticides, as well as naturally occurring inorganic constituents such as major ions and trace elements. The status assessment is intended to characterize the quality of untreated groundwater resources within the primary aquifers in the SESJ and KERN study units, not the quality of drinking water delivered to consumers. Although the status assessment applies to untreated groundwater, Federal and California regulatory and non-regulatory water-quality benchmarks that apply to drinking water are used

  6. Groundwater influence on water budget of a small constructed floodplain wetland in the Ridge and Valley of Virginia, USA

    Directory of Open Access Journals (Sweden)

    Andrea L. Ludwig

    2015-09-01

    New hydrological insights for the region: Data showed that the created wetland met hydrologic success criteria, and that the wetland storage was fully connected with the groundwater table. Water-surface storage fluctuation was not fully explained by precipitation and evapotranspiration, suggesting that storage was highly influenced by groundwater inputs. The potentiometric surface showed that hillslope seep recharge was the dominant groundwater vector. However, during the summer and fall months, the adjacent stream channel was a losing system, and storm-driven rise in stream stage affected wetland storage. The complex hydrology of this relatively small wetland indicates that predicting the fluctuations of storage for design of unconfined floodplain wetlands is challenging, and that if the influence of groundwater seepage is negated, then fluctuations may be underestimated to the point of harming vegetation.

  7. Hydrology and numerical simulation of groundwater movement and heat transport in Snake Valley and surrounding areas, Juab, Miller, and Beaver Counties, Utah, and White Pine and Lincoln Counties, Nevada

    Science.gov (United States)

    Masbruch, Melissa D.; Gardner, Philip M.; Brooks, Lynette E.

    2014-01-01

    Snake Valley and surrounding areas, along the Utah-Nevada state border, are part of the Great Basin carbonate and alluvial aquifer system. The groundwater system in the study area consists of water in unconsolidated deposits in basins and water in consolidated rock underlying the basins and in the adjacent mountain blocks. Most recharge occurs from precipitation on the mountain blocks and most discharge occurs from the lower altitude basin-fill deposits mainly as evapotranspiration, springflow, and well withdrawals.The Snake Valley area regional groundwater system was simulated using a three-dimensional model incorporating both groundwater flow and heat transport. The model was constructed with MODFLOW-2000, a version of the U.S. Geological Survey’s groundwater flow model, and MT3DMS, a transport model that simulates advection, dispersion, and chemical reactions of solutes or heat in groundwater systems. Observations of groundwater discharge by evapotranspiration, springflow, mountain stream base flow, and well withdrawals; groundwater-level altitudes; and groundwater temperatures were used to calibrate the model. Parameter values estimated by regression analyses were reasonable and within the range of expected values.This study represents one of the first regional modeling efforts to include calibration to groundwater temperature data. The inclusion of temperature observations reduced parameter uncertainty, in some cases quite significantly, over using just water-level altitude and discharge observations. Of the 39 parameters used to simulate horizontal hydraulic conductivity, uncertainty on 11 of these parameters was reduced to one order of magnitude or less. Other significant reductions in parameter uncertainty occurred in parameters representing the vertical anisotropy ratio, drain and river conductance, recharge rates, and well withdrawal rates.The model provides a good representation of the groundwater system. Simulated water-level altitudes range over

  8. Geochemical tracing of As pollution in the Orbiel Valley (southern France): 87Sr/86Sr as a tracer of the anthropogenic arsenic in surface and groundwater.

    Science.gov (United States)

    Khaska, Mahmoud; Le Gal La Salle, Corinnne; Lancelot, Joël; Verdoux, Patrick; Boutin, René

    2014-05-01

    The environmental impacts of arsenic mining activities and their effects on ecosystem and human health are observed in many stream waters and groundwater. The aim of this study is to identify the origin of As content in a mining environment using Sr isotopes. At the Salsigne gold mine, before the closure in 2004, high arsenic content has been observed in surface water and groundwater in the Orbiel valley. At the site, immobilization of As, in As rich leachate, is carried out by adding CaO. High contrast in 87Sr/86Sr between Arsenic rich minerals associated with Variscan metamorphic rocks (0.714888-0.718835), together with rich As waste water (0.713463-715477), and the CaO (0.707593) allows as to trace the origin of anthropogenic As. In 2012, Orbiel stream waters were sampled monthly upstream and downstream from the ancient ore processing site and once after an important rainy event (117mm). The upstream valley samples showed low and relatively constant As content with natural regional background of 3.6 and 5.6 μg/L. The rainy event induced only a slight increase in the As content up to 6.3 μg/L. High 87Sr/86Sr ratios suggested an influence of radiogenic Sr issued from the Variscan metamorphic basement. Downstream from the area, the As content was at least10 time as high. In the wet season, stream water As content clearly increased to 13.9-24 μg/L, reaching 120.5 μg/L during the rainy event. Associated 87Sr/86Sr ratio showed to be less radiogenic (0.712276-0.714002). The anti correlation observed between As and 87Sr/86Sr suggest that As issued from a natural origin is characterised by a high 87Sr/86Sr compared to As derived from the CaO treatement used on site and characterized by a low 87Sr/86Sr ratio. During the dry season, increase in As content was observed reaching 110 μg/L. These highlights the contribution of alluvial groundwater to base flow, probably associated with As reach leachate from the site. Contribution from the alluvial aquifer is confirmed by

  9. Remedial investigation work plan for Bear Creek Valley Operable Unit 4 (shallow groundwater in Bear Creek Valley) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    1992-12-01

    The enactment of the Resource Conservation and Recovery Act (RCRA) in 1976 and the Hazardous and Solid Waste Amendments (HSWA) to RCRA in 1984 created management requirements for hazardous waste fadities. The facilities within the Oak Ridge Reservation (ORR) were in the process of meeting the RCRA requirements when ORR was placed on the Comprehensive Environmental Response, Compensation, and Liability Act (CERCIA) National Priorities List (NPL) on November 21, 1989. Under RCRA, the actions typically follow the RCRA Facility Assessment (RIFA)/RCRA Facility Investigation (RFI)/Coffective Measures Study (CMS)/Corrective Measures Implementation process. Under CERCLA, the actions follow the Pre at sign ary Assessment/Site Investigation (PA/Sl) Remedial Investigation Feasibility Study (RI/FS)/Remedial Design/Remedial Action process. The development of this document will incorporate requirements under both RCRA and CERCIA into an RI Work Plan for the lint phase of characterization of Bear Creek Valley (BCV) Operable Unit (OU) 4

  10. Groundwater quality monitoring well installation for Upper Waste Areas Grouping 2 at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    Mortimore, J.A.; Lee, T.A.

    1994-09-01

    This report documents the drilling and installation of seven groundwater quality monitoring (GQM) wells on the perimeter of Upper Waste Area Grouping (WAG) 2. Upper WAG 2 is composed of portions of White Oak Creek (WOC), Melton Branch, two of Melton Branch's tributaries, and the floodplains surrounding these water bodies. The WOC section of the subject site begins at the confluence of WOC and Melton Branch and extends 0.62 mile upstream to the 7,500 bridge. The Melton Branch portion of the site also begins at the confluence of WOC and Melton Branch and extends eastward 0.88 mile upstream. The wells at Upper WAG 2 were drilled and developed between December 1989 and October 1990. These wells were installed to characterize and assess the WAG in accordance with applicable Department of Energy, state, and Environmental Protection Agency regulatory requirements. The purpose of the well installation program was to install GQM wells for groundwater characterization at Upper WAG-2. Data packages produced during installation activities by the ERCE hydrogeologists are an important product of the program. These packages document the well drilling, installation, and development activities and provide valuable data for well sampling and WAG characterization. The forms contained in the packages include predrilling and postdrilling checklists, drilling and construction logs, development and hydraulic conductivity records, and quality control-related documents

  11. Application of water quality index to evaluate groundwater quality (temporal and spatial variation) of an intensively exploited aquifer (Puebla valley, Mexico).

    Science.gov (United States)

    Salcedo-Sánchez, Edith R; Garrido Hoyos, Sofía E; Esteller Alberich, Ma Vicenta; Martínez Morales, Manuel

    2016-10-01

    The spatial and temporal variation of water quality in the urban area of the Puebla Valley aquifer was evaluated using historical and present data obtained during this investigation. The current study assessed water quality based on the Water Quality Index developed by the Canadian Council of Ministers of the Environment (CCME-WQI), which provides a mathematical framework to evaluate the quality of water in combination with a set of conditions representing quality criteria, or limits. This index is flexible regarding the type and number of variables used by the evaluation given that the variables of interest are selected according to the characteristics and objectives of development, conservation and compliance with regulations. The CCME-WQI was calculated using several variables that assess the main use of the wells in the urban area that is public supply, according to criteria for human use and consumption established by Mexican law and international standards proposed by the World Health Organization. The assessment of the index shows a gradual deterioration in the quality of the aquifer over time, as the amount of wells with excellent quality have decreased and those with lower index values (poor quality) have increased throughout the urban area of the Puebla Valley aquifer. The parameters affecting groundwater quality are: total dissolved solids, sulfate, calcium, magnesium and total hardness.

  12. Ground-Water Quality Data in the Owens and Indian Wells Valleys Study Unit, 2006: Results from the California GAMA Program

    Science.gov (United States)

    Densmore, Jill N.; Fram, Miranda S.; Belitz, Kenneth

    2009-01-01

    Ground-water quality in the approximately 1,630 square-mile Owens and Indian Wells Valleys study unit (OWENS) was investigated in September-December 2006 as part of the Priority Basin Project of Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Project was developed in response to the Groundwater Quality Monitoring Act of 2001 and is being conducted by the U.S. Geological Survey (USGS) in collaboration with the California State Water Resources Control Board (SWRCB). The Owens and Indian Wells Valleys study was designed to provide a spatially unbiased assessment of raw ground-water quality within OWENS study unit, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from 74 wells in Inyo, Kern, Mono, and San Bernardino Counties. Fifty-three of the wells were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study area (grid wells), and 21 wells were selected to evaluate changes in water chemistry in areas of interest (understanding wells). The ground-water samples were analyzed for a large number of synthetic organic constituents [volatile organic compounds (VOCs), pesticides and pesticide degradates, pharmaceutical compounds, and potential wastewater- indicator compounds], constituents of special interest [perchlorate, N-nitrosodimethylamine (NDMA), and 1,2,3- trichloropropane (1,2,3-TCP)], naturally occurring inorganic constituents [nutrients, major and minor ions, and trace elements], radioactive constituents, and microbial indicators. Naturally occurring isotopes [tritium, and carbon-14, and stable isotopes of hydrogen and oxygen in water], and dissolved noble gases also were measured to help identify the source and age of the sampled ground water. This study evaluated the quality of raw ground water in the aquifer in the OWENS study unit and did not attempt to evaluate the quality of treated water

  13. Hydrogeological characterization and environmental effects of the deteriorating urban karst groundwater in a karst trough valley: Nanshan, SW China

    Science.gov (United States)

    Jiang, Yongjun; Cao, Min; Yuan, Daoxian; Zhang, Yuanzhu; He, Qiufang

    2018-02-01

    The unique hydrogeology of karst makes the associated groundwater respond quickly to rainfall events and vulnerable to anthropogenic pollutions. In this study, high-frequency monitoring of spring discharge, temperature, electrical conductivity (EC) and pH, along with monthly hydrochemical and microbial analyses, was undertaken at the outlet of Laolondong karst underground river in Nanshan, southwestern China. The aim was to explore the environmental effects of the catchment's urban area on the karst groundwater resources. The monitoring data of a tracer test and the response of discharge to rainfall events demonstrate that conduits and narrow fissures coexist in the Laolongdong karst aquifer. The EC, Na+, Cl- and SO4 2- values (840 μS/cm, 33.7, 38.6 and 137.2 μg/L, respectively), along with high concentrations of fecal coliform bacteria, at the outlet indicate considerable urban pollution in this area. The contaminants sulfate and nitrate showed different relationships with discharge and EC in different stages of a rainfall event. This behavior provided information about aquifer structure and the influence of transport properties. Meanwhile, the hydrological processes of groundwater flow could be modified by urbanization and result in increasing magnitude of urban floods in the underground river. In addition, sulfuric and nitric acids introduced by urbanization not only impact the karst groundwater quality, but also result in a significant perturbation to the carbon cycling system in the karst area.

  14. Groundwater quality monitoring well installation for Waste Area Grouping 3 at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    Mortimore, J.A.; Ebers, M.L.

    1994-09-01

    This report documents the drilling and installation of 15 groundwater quality monitoring (GQM) wells on the perimeter of Waste Area Grouping (WAG) 3. WAG 3 is located in Melton Valley, approximately 3,000 ft west of the west gate of Oak Ridge National Laboratory, and consists of an estimated 22 acres. The subject site contains three solid waste management units: the Contractors' Landfill, the Closed Scrap Metal Area, and Solid Waste Storage Area 3. The wells at WAG 3 were drilled and developed between September 1987 and August 1990. These wells were installed to characterize and assess the WAG in accordance with applicable Department of Energy, state, and Environmental Protection Agency regulatory requirements. The wells at WAG 3 were drilled with auger or air rotary rigs. Depending upon the hydrogeologic conditions present at each proposed well location, one of four basic installation methods was utilized. The purpose of the well installation program was to install GQM wells for groundwater characterization at WAG 3. Data packages produced during installation activities by the ERCE hydrogeologists are an important product of the program. These packages document the well drilling, installation, and development activities and provide valuable data for well sampling and WAG characterization. The forms contained in the packages include predrilling and postdrilling checklists, drilling and construction logs, development and hydraulic conductivity records, and quality control-related documents

  15. Groundwater quality monitoring well installation for Waste Area Grouping 5 at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    Mortimore, J.A.; Ebers, M.L.

    1994-09-01

    This report documents the drilling and installation of 22 groundwater quality monitoring (GQM) wells on the perimeter of Waste Area Grouping (WAG) 5. WAG 5 is located south of the Oak Ridge National Laboratory main plant area in Melton Valley and includes 33 solid waste management units. The wells at WAG 5 were drilled and developed between July 1987 and March 1990. These wells were installed to characterize and assess the WAG in accordance with applicable Department of Energy, state, and Environmental Protection Agency regulatory requirements. The purpose of the well installation program was to install GQM wells for groundwater characterization at WAG 5. Data packages produced during installation activities by the ERCE hydrogeologists are an important product of the program. These packages document the well drilling, installation, and development activities and provide valuable data for well sampling and WAG characterization. The forms contained in the packages include predrilling and postdrilling checklists, drilling and construction logs, development and hydraulic conductivity records, and quality control-related documents

  16. Groundwater quality monitoring well installation for Waste Area Grouping 4 at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    Mortimore, J.A.

    1994-09-01

    This report documents the drilling and installation of 15 groundwater quality monitoring (GQM) wells on the perimeter of Waste Area Grouping (WAG) 4. WAG 4 is comprised of about 27 acres located in Melton Valley approximately 2700 ft southwest of the Oak Ridge National Laboratory main plant. It contains three inactive solid waste management units: (1) the abandoned intermediate level liquid waste transfer line located along the WAG's northwestern boundary, (2) the experimental pilot pit area, and (3) SWSA 4, the largest unit in the WAG. The wells at WAG 4 were drilled and developed between September 1987 and October 1990. These wells were installed to characterize and assess the WAG in accordance with applicable Department of Energy (DOE), state, and Environmental Protection Agency regulatory requirements. The wells at WAG 4 were drilled with auger or air rotary rigs. Depending on the hydrogeologic conditions present at each proposed well location, one of four basic installation methods was utilized. The purpose of the well installation program was to install GQM wells for groundwater characterization at WAG 4. Data packages produced during installation activities by the ERCE hydrogeologists are an important product of the program. These packages document the well drilling, installation, and development activities and provide valuable data for well sampling and WAG characterization. The forms contained in the packages include predrilling and postdrilling checklists, drilling and construction logs, development and hydraulic conductivity records, and quality control-related documents

  17. Report on surface geology and groundwater investigations of Mortons and Green Valley Well Fields. Final technical report, November 1980-May 1982. [Proposed WyCoalGas Project, Converse County, Wyoming; site evaluation

    Energy Technology Data Exchange (ETDEWEB)

    None

    1982-01-01

    The general region of investigation of this report is in the southern part of the Powder River Basin near the Town of Douglas, Wyoming. Two specific areas within this region were investigated to determine the groundwater potential with drilling and testing programs during the years 1973 to 1975. One area of investigation is located approximately 12 miles west of Douglas in T32 and 33N, R73 and 74W, and is known as the Green Valley Well Field. This area is situated in the foothills of the north end of the Laramie Range and encompasses approximately 25 square miles. In this area the Madison Formation limestone and the Flathead Formation sandstone are the aquifers of interest for groundwater production. The second area is located approximately 13 miles north of Douglas in T34 and 35N, R70 and 71W, and is known as the Mortons Well Field. This area encompasses about 30 square miles. In this area, the Lance Formation and Fox Hills Formation sandstones are the aquifers of interest. Contained within the body of this report are two geologic studies prepared by consulting geologists, Dr. Peter Huntoon and Henry Richter. These studies define the pertinent structural and groundwater geologic features in and in the vicinities of the Mortons and Green Valley Well Fields. A relatively complex structural geology was encountered in the Green Valley area. The study of the Mortons area suggests that the geology of this area is relatively uniform. Inventories of the water users in the vicinities of the two study areas are included at the back of this report in Appendix B. These inventories are comprised of water appropriations as recognized by the Wyoming State Engineer's Office. Both groundwater and surface water appropriations are inventoried within the Green Valley study area. Only groundwater appropriations are inventoried within the Mortons study area.

  18. Ground-water flow directions and estimation of aquifer hydraulic properties in the lower Great Miami River Buried Valley aquifer system, Hamilton Area, Ohio

    Science.gov (United States)

    Sheets, Rodney A.; Bossenbroek, Karen E.

    2005-01-01

    The Great Miami River Buried Valley Aquifer System is one of the most productive sources of potable water in the Midwest, yielding as much as 3,000 gallons per minute to wells. Many water-supply wells tapping this aquifer system are purposely placed near rivers to take advantage of induced infiltration from the rivers. The City of Hamilton's North Well Field consists of 10 wells near the Great Miami River, all completed in the lower Great Miami River Buried Valley Aquifer System. A well-drilling program and a multiple-well aquifer test were done to investigate ground-water flow directions and to estimate aquifer hydraulic properties in the lower part of the Great Miami River Buried Valley Aquifer System. Descriptions of lithology from 10 well borings indicate varying amounts and thickness of clay or till, and therefore, varying levels of potential aquifer confinement. Borings also indicate that the aquifer properties can change dramatically over relatively short distances. Grain-size analyses indicate an average bulk hydraulic conductivity value of aquifer materials of 240 feet per day; the geometric mean of hydraulic conductivity values of aquifer material was 89 feet per day. Median grain sizes of aquifer material and clay units were 1.3 millimeters and 0.1 millimeters, respectively. Water levels in the Hamilton North Well Field are affected by stream stage in the Great Miami River and barometric pressure. Bank storage in response to stream stage is evident. Results from a multiple-well aquifer test at the well field indicate, as do the lithologic descriptions, that the aquifer is semiconfined in some areas and unconfined in others. Transmissivity and storage coefficient of the semiconfined part of the aquifer were 50,000 feet squared per day and 5x10-4, respectively. The average hydraulic conductivity (450 feet per day) based on the aquifer test is reasonable for glacial outwash but is higher than calculated from grain-size analyses, implying a scale effect

  19. Nutrient management programs, nitrogen fertilizer practices, and groundwater quality in Nebraska's Central Platte Valley (U.S.), 1989-1998.

    Science.gov (United States)

    Daberkow, S; Taylor, H; Gollehon, N; Moravek, M

    2001-11-21

    Given the societal concern about groundwater pollution from agricultural sources, public programs have been proposed or implemented to change farmer behavior with respect to nutrient use and management. However, few of these programs designed to change farmer behavior have been evaluated due to the lack of detailed data over an appropriate time frame. The Central Platte Natural Resources District (CPNRD) in Nebraska has identified an intensively cultivated, irrigated area with average groundwater nitrate-nitrogen (N) levels about double the EPA"s safe drinking water standard. The CPNRD implemented a joint education and regulatory N management program in the mid-1980s to reduce groundwater N. This analysis reports N use and management, yield, and groundwater nitrate trends in the CPNRD for nearly 3000 continuous-corn fields from 1989 to 1998, where producers faced limits on the timing of N fertilizer application but no limits on amounts. Groundwater nitrate levels showed modest improvement over the 10 years of this analysis, falling from the 1989-1993 average of 18.9 to 18.1 mg/l during 1994-1998. The availability of N in excess of crop needs was clearly documented by the CPNRD data and was related to optimistic yield goals, irrigation water use above expected levels, and lack of adherence to commercial fertilizer application guidelines. Over the 10-year period of this analysis, producers reported harvesting an annual average of 9729 kg/ha, 1569 kg/ha (14%) below the average yield goal. During 1989-1998, producers reported annually applying an average of 162.5 kg/ha of commercial N fertilizer, 15.7 kg/ha (10%) above the guideline level. Including the N contribution from irrigation water, the potential N contribution to the environment (total N available less estimated crop use) was estimated at 71.7 kg/ha. This is an estimate of the nitrates available for denitrification, volatilization, runoff, future soil N, and leaching to groundwater. On average, between 1989

  20. Recalibration of a ground-water flow model of the Mississippi River Valley alluvial aquifer in Southeastern Arkansas, 1918, with simulations of hydraulic heads caused by projected ground-water withdrawals through 2049

    Science.gov (United States)

    Stanton, Gregory P.; Clark, Brian R.

    2003-01-01

    The Mississippi River Valley alluvial aquifer, encompassing parts of Arkansas, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee supplies an average of 5 billion gallons of water per day. However, withdrawals from the aquifer in recent years have caused considerable drawdown in the hydraulic heads in southeastern Arkansas and other areas. The effects of current ground-water withdrawals and potential future withdrawals on water availability are major concerns of water managers and users as well as the general public. A full understanding of the behavior of the aquifer under various water-use scenarios is critical for the development of viable water-management and alternative source plans. To address these concerns, the U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, Vicksburg District, and the Arkansas Soil and Water Conservation Commission developed and calibrated a ground-water flow model for the Mississippi River valley alluvial aquifer in southeastern Arkansas to simulate hydraulic heads caused by projected ground-water withdrawals. A previously published ground-water flow model for the alluvial aquifer in southeastern Arkansas was updated and recalibrated to reflect more current pumping stresses with additional stress periods added to bring the model forward from 1982 to 1998. The updated model was developed and calibrated with MODFLOW-2000 finite difference numerical modeling and parameter estimation software. The model was calibrated using hydraulic-head data collected during 1972 and 1982 and hydraulic-head measurements made during spring (February to April) of 1992 and 1998. The residuals for 1992 and 1998 have a mean absolute value of 4.74 and 5.45 feet, respectively, and a root mean square error of 5.9 and 6.72 feet, respectively. The effects of projected ground-water withdrawals were simulated through 2049 in three predictive scenarios by adding five additional stress periods of 10 years each. In the three scenarios

  1. Geohydrology, water quality, and simulation of groundwater flow in the stratified-drift aquifer system in Virgil Creek and Dryden Lake Valleys, Town of Dryden, Tompkins County, New York

    Science.gov (United States)

    Miller, Todd S.; Bugliosi, Edward F.

    2013-01-01

    stratified-drift aquifers at the Valley Heads Moraine, which consists of heterogeneous sediments including coarse-grained outwash and kame sediments, as well as zones containing till with a fine-grained matrix. In the southern part of the study area, the confining units are thin and likely to be discontinuous in some places, resulting in windows of permeable sediment, which can more readily transmit recharge from precipitation and from tributaries that lose water as they flow over the valley floor. In contrast, in the northern part of the study area, the confining units are thick, continuous, and comprise homogeneous fine-grained sediments that more effectively confine the aquifers than in the southern part of the study area. Most groundwater in the northern part of the study area discharges to the Village of Dryden municipal production wells, to the outlet to Dryden Lake, to Virgil Creek, and as groundwater underflow that exits the northern boundary of the study area. Most northward-flowing groundwater in the southern part of the study area discharges to Dryden Lake, to the inlet to Dryden Lake, and to homeowner, nonmunicipal community (a mobile home community and several apartments), and commercial wells. Most of this pumped water is returned to the groundwater system via septic systems. Most southward-flowing groundwater in the southern part of the study area discharges to the headwaters of Owego Creek and to agricultural wells; some flow also exits the southern boundary of the study area as groundwater underflow. The largest user of groundwater in the study area is the Village of Dryden. Water use in the village has approximately tripled between the early 1970s when withdrawals ranged between 18 and 30 million gallons per year (Mgal/yr) and from 2000 through 2008 when withdrawals ranged between 75 and 85 Mgal/yr. The estimated groundwater use by homeowners, nonmunicipal communities, and small commercial facilities outside the area supplied by the Village of Dryden

  2. Probability of Unmixed Young Groundwater (defined using chlorofluorocarbon-11 concentrations and tritium activities) in the Eagle River Watershed Valley-Fill Aquifer, Eagle County, North-Central Colorado, 2006-2007

    Science.gov (United States)

    Rupert, Michael G.; Plummer, Niel

    2009-01-01

    This raster data set delineates the predicted probability of unmixed young groundwater (defined using chlorofluorocarbon-11 concentrations and tritium activities) in groundwater in the Eagle River watershed valley-fill aquifer, Eagle County, North-Central Colorado, 2006-2007. This data set was developed by a cooperative project between the U.S. Geological Survey, Eagle County, the Eagle River Water and Sanitation District, the Town of Eagle, the Town of Gypsum, and the Upper Eagle Regional Water Authority. This project was designed to evaluate potential land-development effects on groundwater and surface-water resources so that informed land-use and water management decisions can be made. This groundwater probability map and its associated probability maps were developed as follows: (1) A point data set of wells with groundwater quality and groundwater age data was overlaid with thematic layers of anthropogenic (related to human activities) and hydrogeologic data by using a geographic information system to assign each well values for depth to groundwater, distance to major streams and canals, distance to gypsum beds, precipitation, soils, and well depth. These data then were downloaded to a statistical software package for analysis by logistic regression. (2) Statistical models predicting the probability of elevated nitrate concentrations, the probability of unmixed young water (using chlorofluorocarbon-11 concentrations and tritium activities), and the probability of elevated volatile organic compound concentrations were developed using logistic regression techniques. (3) The statistical models were entered into a GIS and the probability map was constructed.

  3. Tectonic Setting of the Gravity Fault and Implications for Ground-Water Resources in the Death Valley Region, Nevada and California

    Science.gov (United States)

    Blakely, R. J.; Sweetkind, D. S.; Faunt, C. C.; Jansen, J. R.; McPhee, D. K.; Morin, R. L.

    2007-12-01

    The Amargosa trough, extending south from Crater Flat basin to the California-Nevada state line, is believed to be a transtensional basin accommodated in part by strike-slip displacement on the northwest-striking State Line fault and normal displacement on the north-striking Gravity fault. The Gravity fault, lying along the eastern margin of the Amargosa trough, was first recognized in the 1970s on the basis of correlations between gravity anomalies and a prominent spring line in Amargosa Valley. The Gravity fault causes an inflection in water-table levels, similar to other (but not all) normal faults in the area. Pools along the spring line, some of which lie within Death Valley National Park and Ash Meadows Wildlife Refuge, include endemic species potentially threatened by increasing agricultural activities in Amargosa Valley immediately to the west, where water tables are declining. Most of the springs and pools lie east of the Gravity fault, however, and it is important to understand the role that the Gravity fault plays in controlling ground-water flow. We have conducted a variety of geophysical investigations at various scales to better understand the tectonic framework of the Amargosa Desert and support new ground-water-flow models. Much of our focus has been on the tectonic interplay of the State Line, Gravity, and other faults in the area using gravity, ground-magnetic, audiomagnetotelluric (AMT), and time-domain electromagnetic (TEM) surveys. With 1250 new gravity measurements from Ash Meadows and Stewart Valley, we have developed a revised three-dimensional crustal model of the Amargosa trough constrained by well information and geologic mapping. The model predicts approximately 2 km of vertical offset on the Gravity fault but also suggests a complex structural framework. The fault is conventionally seen as a simple, down-to-the-west normal fault juxtaposing permeable pre-Tertiary carbonate rocks to the east against less permeable Tertiary sediments to

  4. Groundwater-level change and evaluation of simulated water levels for irrigated areas in Lahontan Valley, Churchill County, west-central Nevada, 1992 to 2012

    Science.gov (United States)

    Smith, David W.; Buto, Susan G.; Welborn, Toby L.

    2016-09-14

    The acquisition and transfer of water rights to wetland areas of Lahontan Valley, Nevada, has caused concern over the potential effects on shallow aquifer water levels. In 1992, water levels in Lahontan Valley were measured to construct a water-table map of the shallow aquifer prior to the effects of water-right transfers mandated by the Fallon Paiute-Shoshone Tribal Settlement Act of 1990 (Public Law 101-618, 104 Stat. 3289). From 1992 to 2012, approximately 11,810 water-righted acres, or 34,356 acre-feet of water, were acquired and transferred to wetland areas of Lahontan Valley. This report documents changes in water levels measured during the period of water-right transfers and presents an evaluation of five groundwater-flow model scenarios that simulated water-level changes in Lahontan Valley in response to water-right transfers and a reduction in irrigation season length by 50 percent.Water levels measured in 98 wells from 2012 to 2013 were used to construct a water-table map. Water levels in 73 of the 98 wells were compared with water levels measured in 1992 and used to construct a water-level change map. Water-level changes in the 73 wells ranged from -16.2 to 4.1 feet over the 20-year period. Rises in water levels in Lahontan Valley may correspond to annual changes in available irrigation water, increased canal flows after the exceptionally dry and shortened irrigation season of 1992, and the increased conveyance of water rights transferred to Stillwater National Wildlife Refuge. Water-level declines generally occurred near the boundary of irrigated areas and may be associated with groundwater pumping, water-right transfers, and inactive surface-water storage reservoirs. The largest water-level declines were in the area near Carson Lake.Groundwater-level response to water-right transfers was evaluated by comparing simulated and observed water-level changes for periods representing water-right transfers and a shortened irrigation season in areas near Fallon

  5. Death valley regional ground-water flow model calibration using optimal parameter estimation methods and geoscientific information systems

    Science.gov (United States)

    D'Agnese, F. A.; Faunt, C.C.; Hill, M.C.; Turner, A.K.

    1999-01-01

    A regional-scale, steady-state, saturated-zone ground-water flow model was constructed to evaluate potential regional ground-water flow in the vicinity of Yucca Mountain, Nevada. The model was limited to three layers in an effort to evaluate the characteristics governing large-scale subsurface flow. Geoscientific information systems (GSIS) were used to characterize the complex surface and subsurface hydrogeologic conditions of the area, and this characterization was used to construct likely conceptual models of the flow system. Subsurface properties in this system vary dramatically, producing high contrasts and abrupt contacts. This characteristic, combined with the large scale of the model, make zonation the logical choice for representing the hydraulic-conductivity distribution. Different conceptual models were evaluated using sensitivity analysis and were tested by using nonlinear regression to determine parameter values that are optimal, in that they provide the best match between the measured and simulated heads and flows. The different conceptual models were judged based both on the fit achieved to measured heads and spring flows, and the plausibility of the optimal parameter values. One of the conceptual models considered appears to represent the system most realistically. Any apparent model error is probably caused by the coarse vertical and horizontal discretization.A regional-scale, steady-state, saturated-zone ground-water flow model was constructed to evaluate potential regional ground-water flow in the vicinity of Yucca Mountain, Nevada. The model was limited to three layers in an effort to evaluate the characteristics governing large-scale subsurface flow. Geoscientific information systems (GSIS) were used to characterize the complex surface and subsurface hydrogeologic conditions of the area, and this characterization was used to construct likely conceptual models of the flow system. Subsurface properties in this system vary dramatically, producing

  6. Chemical analyses of ground-water samples from the Rio Grande Valley in the vicinity of Albuquerque, New Mexico, October 1993 through January 1994

    Science.gov (United States)

    Wilkins, D.W.; Schlottmann, J.L.; Ferree, D.M.

    1996-01-01

    A study was conducted to investigate general ground-water- quality conditions and contaminant locations in the Rio Grande Valley in the vicinity of Albuquerque, New Mexico. Water samples from 36 observation wells in 12 well nests were analyzed. The well nests are located along three roads near the Rio Grande--two well nests near Paseo del Norte, five well nests near Monta?o Road, and five well nests near Rio Bravo Boulevard. The water samples were collected from October 19, 1993, through January 18, 1994. Water-quality types by major-ion composition were calcium bicarbonate (found in most samples), sodium sulfate, calcium sulfate, and calcium sulfate chloride. Nutrients were detected in all but one sample. Ammonia was detected in 34 samples, nitrite in 4 samples, and nitrate in 17 samples. Orthophosphate was detected in 31 samples. Organic carbon was detected in all samples collected. The trace elements arsenic and barium were detected in all samples and zinc in 31 samples. Fourteen samples contained detectable copper. Cadmium was detected in one sample, chromium in two samples, lead in four samples, and selenium in two samples. Mercury and silver were not detected.

  7. Precipitation and Runoff Simulations of the Carson Range and Pine Nut Mountains, and Updated Estimates of Ground-Water Inflow and the Ground-Water Budgets for Basin-Fill Aquifers of Carson Valley, Douglas County, Nevada, and Alpine County, California

    Science.gov (United States)

    Jeton, Anne E.; Maurer, Douglas K.

    2007-01-01

    Recent estimates of ground-water inflow to the basin-fill aquifers of Carson Valley, Nevada, and California, from the adjacent Carson Range and Pine Nut Mountains ranged from 22,000 to 40,000 acre-feet per year using water-yield and chloride-balance methods. In this study, watershed models were developed for watersheds with perennial streams and for watersheds with ephemeral streams in the Carson Range and Pine Nut Mountains to provide an independent estimate of ground-water inflow. This report documents the development and calibration of the watershed models, presents model results, compares the results with recent estimates of ground-water inflow to the basin-fill aquifers of Carson Valley, and presents updated estimates of the ground-water budget for basin-fill aquifers of Carson Valley. The model used for the study was the Precipitation-Runoff Modeling System, a physically based, distributed-parameter model designed to simulate precipitation and snowmelt runoff as well as snowpack accumulation and snowmelt processes. Geographic Information System software was used to manage spatial data, characterize model drainages, and to develop Hydrologic Response Units. Models were developed for * Two watersheds with gaged perennial streams in the Carson Range and two watersheds with gaged perennial streams in the Pine Nut Mountains using measured daily mean runoff, * Ten watersheds with ungaged perennial streams using estimated daily mean runoff, * Ten watershed with ungaged ephemeral streams in the Carson Range, and * A large area of ephemeral runoff near the Pine Nut Mountains. Models developed for the gaged watersheds were used as index models to guide the calibration of models for ungaged watersheds. Model calibration was constrained by daily mean runoff for 4 gaged watersheds and for 10 ungaged watersheds in the Carson Range estimated in a previous study. The models were further constrained by annual precipitation volumes estimated in a previous study to provide

  8. Simulations of Ground-Water Flow and Particle Pathline Analysis in the Zone of Contribution of a Public-Supply Well in Modesto, Eastern San Joaquin Valley, California

    Science.gov (United States)

    Burow, Karen R.; Jurgens, Bryant C.; Kauffman, Leon J.; Phillips, Steven P.; Dalgish, Barbara A.; Shelton, Jennifer L.

    2008-01-01

    Shallow ground water in the eastern San Joaquin Valley is affected by high nitrate and uranium concentrations and frequent detections of pesticides and volatile organic compounds (VOC), as a result of ground-water development and intensive agricultural and urban land use. A single public-supply well was selected for intensive study to evaluate the dominant processes affecting the vulnerability of public-supply wells in the Modesto area. A network of 23 monitoring wells was installed, and water and sediment samples were collected within the approximate zone of contribution of the public-supply well, to support a detailed analysis of physical and chemical conditions and processes affecting the water chemistry in the well. A three-dimensional, steady-state local ground-water-flow and transport model was developed to evaluate the age of ground water reaching the well and to evaluate the vulnerability of the well to nonpoint source input of nitrate and uranium. Particle tracking was used to compute pathlines and advective travel times in the ground-water flow model. The simulated ages of particles reaching the public-supply well ranged from 9 to 30,000 years, with a median of 54 years. The age of the ground water contributed to the public-supply well increased with depth below the water table. Measured nitrate concentrations, derived primarily from agricultural fertilizer, were highest (17 milligrams per liter) in shallow ground water and decreased with depth to background concentrations of less than 2 milligrams per liter in the deepest wells. Because the movement of water is predominantly downward as a result of ground-water development, and because geochemical conditions are generally oxic, high nitrate concentrations in shallow ground water are expected to continue moving downward without significant attenuation. Simulated long-term nitrate concentrations indicate that concentrations have peaked and will decrease in the public-supply well during the next 100 years

  9. The hydrochemical identification of groundwater flowing to the Bet She’an-Harod multiaquifer system (Lower Jordan Valley) by rare earth elements, yttrium, stable isotopes (H, O) and Tritium

    International Nuclear Information System (INIS)

    Siebert, Christian; Rosenthal, Eliahu; Möller, Peter; Rödiger, Tino; Meiler, Miki

    2012-01-01

    The Bet She’an and Harod Valleys in Israel are regional recipients and mixing zones for groundwater draining from a multiple aquifer system, which includes carbonate and basalt aquifers and deep-seated pressurized brines. The aquifers drain through two types of outlets, distinct and mixed. The latter type is mainly conditioned by the occurrence of fault-blocks related to the Jordan Rift system, which act as connecting media between the aquifers and facilitate interaquifer flow. Conjoint application of rare earth element distribution and water isotopes enables detection of the local areas replenishment by rainfall infiltration and, in connection with the position of wells or springs, the identification of groundwater flow paths. Once stationary equilibria are established changes of REY composition between REY in groundwater and their surface adsorption, are negligible. In areas with little soil coverage and vegetation even recharge over young Tertiary and diagenetic Cretaceous limestones is distinguishable by their REY distribution patterns. Groundwater recharged over Tertiary limestones show higher REY abundance and more significant Ce anomalies than those derived from the Cretaceous limestones. Weathering of alkali olivine basalts leads to REY patterns in groundwater depleted in the middle REE. The improved knowledge of the hydrological systems is thought to be useful for regional hydrogeological modeling and for designing rational water management schemes.

  10. Exploratory tests of washing radioactive sludge samples from the Melton Valley and evaporator facility storage tanks at ORNL

    International Nuclear Information System (INIS)

    Sears, M.B.; Botts, J.L.; Keller, J.M.

    1991-09-01

    Exploratory tests were initiated to wash radioactive sludge samples from the waste storage tanks at the Oak Ridge National Laboratory (ORNL). The purpose was to provide preliminary information about (1) the anions in the sludge phase that are soluble in water or dilute acid (e.g., the anions in the interstitial liquid) and (2) the solubilities of sludge constituents in water under process conditions. The experiments were terminated before completion due to changing priorities by the Department of Energy (DOE). This memorandum was prepared primarily for documentation purposes and presents the incomplete data. 3 refs., 13 tabs

  11. Quality of Shallow Groundwater and Drinking Water in the Mississippi Embayment-Texas Coastal Uplands Aquifer System and the Mississippi River Valley Alluvial Aquifer, South-Central United States, 1994-2004

    Science.gov (United States)

    Welch, Heather L.; Kingsbury, James A.; Tollett, Roland W.; Seanor, Ronald C.

    2009-01-01

    The Mississippi embayment-Texas coastal uplands aquifer system is an important source of drinking water, providing about 724 million gallons per day to about 8.9 million people in Texas, Louisiana, Mississippi, Arkansas, Missouri, Tennessee, Kentucky, Illinois, and Alabama. The Mississippi River Valley alluvial aquifer ranks third in the Nation for total withdrawals of which more than 98 percent is used for irrigation. From 1994 through 2004, water-quality samples were collected from 169 domestic, monitoring, irrigation, and public-supply wells in the Mississippi embayment-Texas coastal uplands aquifer system and the Mississippi River Valley alluvial aquifer in various land-use settings and of varying well capacities as part of the U.S. Geological Survey's National Water-Quality Assessment Program. Groundwater samples were analyzed for physical properties and about 200 water-quality constituents, including total dissolved solids, major inorganic ions, trace elements, radon, nutrients, dissolved organic carbon, pesticides, pesticide degradates, and volatile organic compounds. The occurrence of nutrients and pesticides differed among four groups of the 114 shallow wells (less than or equal to 200 feet deep) in the study area. Tritium concentrations in samples from the Holocene alluvium, Pleistocene valley trains, and shallow Tertiary wells indicated a smaller component of recent groundwater than samples from the Pleistocene terrace deposits. Although the amount of agricultural land overlying the Mississippi River Valley alluvial aquifer was considerably greater than areas overlying parts of the shallow Tertiary and Pleistocene terrace deposits wells, nitrate was rarely detected and the number of pesticides detected was lower than other shallow wells. Nearly all samples from the Holocene alluvium and Pleistocene valley trains were anoxic, and the reducing conditions in these aquifers likely result in denitrification of nitrate. In contrast, most samples from the

  12. Hanford groundwater scenario studies

    International Nuclear Information System (INIS)

    Arnett, R.C.; Gephart, R.E.; Deju, R.A.; Cole, C.R.; Ahlstrom, S.W.

    1977-05-01

    This report documents the results of two Hanford groundwater scenario studies. The first study examines the hydrologic impact of increased groundwater recharge resulting from agricultural development in the Cold Creek Valley located west of the Hanford Reservation. The second study involves recovering liquid radioactive waste which has leaked into the groundwater flow system from a hypothetical buried tank containing high-level radioactive waste. The predictive and control capacity of the onsite Hanford modeling technology is used to evaluate both scenarios. The results of the first study indicate that Cold Creek Valley irrigationis unlikely to cause significant changes in the water table underlying the high-level waste areas or in the movement of radionuclides already in the groundwater. The hypothetical tank leak study showed that an active response (in this case waste recovery) can be modeled and is a possible alternative to passive monitoring of radionuclide movement in the unlikely event that high-level waste is introduced into the groundwater

  13. Groundwater quality and simulation of sources of water to wells in the Marsh Creek valley at the U.S. Geological Survey Northern Appalachian Research Laboratory, Tioga County, Pennsylvania

    Science.gov (United States)

    Risser, Dennis W.; Breen, Kevin J.

    2012-01-01

    This report provides a November 2010 snapshot of groundwater quality and an analysis of the sources of water to wells at the U.S. Geological Survey (USGS) Northern Appalachian Research Laboratory (NARL) near Wellsboro, Pennsylvania. The laboratory, which conducts fisheries research, currently (2011) withdraws 1,000 gallons per minute of high-quality groundwater from three wells completed in the glacial sand and gravel aquifer beneath the Marsh Creek valley; a fourth well that taps the same aquifer provides the potable supply for the facility. The study was conducted to document the source areas and quality of the water supply for this Department of Interior facility, which is surrounded by the ongoing development of natural gas from the Marcellus Shale. Groundwater samples were collected from the four wells used by the NARL and from two nearby domestic-supply wells. The domestic-supply wells withdraw groundwater from bedrock of the Catskill Formation. Samples were analyzed for major ions, nutrients, trace metals, radiochemicals, dissolved gases, and stable isotopes of oxygen and hydrogen in water and carbon in dissolved carbonate to document groundwater quality. Organic constituents (other than hydrocarbon gases) associated with hydraulic fracturing and other human activities were not analyzed as part of this assessment. Results show low concentrations of all constituents. Only radon, which ranged from 980 to 1,310 picocuries per liter, was somewhat elevated. These findings are consistent with the pristine nature of the aquifer in the Marsh Creek valley, which is the reason the laboratory was sited at this location. The sources of water and areas contributing recharge to wells were identified by the use of a previously documented MODFLOW groundwater-flow model for the following conditions: (1) withdrawals of 1,000 to 3,000 gallons per minute from the NARL wells, (2) average or dry hydrologic conditions, and (3) withdrawals of 1,000 gallons per minute from a new

  14. Three-dimensional hydrogeologic framework model for use with a steady-state numerical ground-water flow model of the Death Valley regional flow system, Nevada and California

    International Nuclear Information System (INIS)

    Belcher, W.R.; Faunt, C.C.; D'Agnese, F.A.

    2002-01-01

    The U.S. Geological Survey, in cooperation with the Department of Energy and other Federal, State, and local agencies, is evaluating the hydrogeologic characteristics of the Death Valley regional ground-water flow system. The ground-water flow system covers and area of about 100,000 square kilometers from latitude 35 degrees to 38 degrees 15 minutes North to longitude 115 degrees to 118 degrees West, with the flow system proper comprising about 45,000 square kilometers. The Death Valley regional ground-water flow system is one of the larger flow systems within the Southwestern United States and includes in its boundaries the Nevada Test Site, Yucca Mountain, and much of Death Valley. Part of this study includes the construction of a three-dimensional hydrogeologic framework model to serve as the foundation for the development of a steady-state regional ground-water flow model. The digital framework model provides a computer-based description of the geometry and composition of the hydro geologic units that control regional flow. The framework model of the region was constructed by merging two previous framework models constructed for the Yucca Mountain Project and the Environmental Restoration Program Underground Test Area studies at the Nevada Test Site. The hydrologic characteristics of the region result from a currently arid climate and complex geology. Interbasinal regional ground-water flow occurs through a thick carbonate-rock sequence of Paleozoic age, a locally thick volcanic-rock sequence of Tertiary age, and basin-fill alluvium of Tertiary and Quaternary age. Throughout the system, deep and shallow ground-water flow may be controlled by extensive and pervasive regional and local faults and fractures. The framework model was constructed using data from several sources to define the geometry of the regional hydrogeologic units. These data sources include (1) a 1:250,000-scale hydrogeologic-map compilation of the region; (2) regional-scale geologic cross

  15. Status of groundwater quality in the Borrego Valley, Central Desert, and Low-Use Basins of the Mojave and Sonoran Deserts study unit, 2008-2010: California GAMA Priority Basin Project

    Science.gov (United States)

    Parsons, Mary C.; Hancock, Tracy Connell; Kulongoski, Justin T.; Belitz, Kenneth

    2014-01-01

    Groundwater quality in the approximately 963-square-mile Borrego Valley, Central Desert, and Low-Use Basins of the Mojave and Sonoran Deserts study unit was investigated as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study unit is located in southern California in San Bernardino, Riverside, San Diego, and Imperial Counties. The GAMA Priority Basin Project is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey and the Lawrence Livermore National Laboratory. The GAMA Borrego Valley, Central Desert, and Low-Use Basins of the Mojave and Sonoran Deserts study was designed to provide a spatially unbiased assessment of the quality of untreated (raw) groundwater in the primary aquifer system. The assessment is based on water-quality and ancillary data collected by the U.S. Geological Survey from 52 wells (49 grid wells and 3 understanding wells) and on water-quality data from the California Department of Public Health database. The primary aquifer system was defined by the depth intervals of the wells listed in the California Department of Public Health database for the Borrego Valley, Central Desert, and Low-Use Basins of the Mojave and Sonoran Deserts study unit. The quality of groundwater in the primary aquifer system may be different from that in the shallower or deeper water-bearing zones; shallow groundwater may be more vulnerable to surficial contamination. This study assesses the status of the current quality of the groundwater resource by using data from samples analyzed for volatile organic compounds (VOCs), pesticides, and naturally occurring inorganic constituents, such as major ions and trace elements. This status assessment is intended to characterize the quality of groundwater resources in the primary aquifer system of the Borrego Valley, Central Desert, and Low-Use Basins of the Mojave and Sonoran Deserts study unit, not the

  16. Groundwater-quality data in the Borrego Valley, Central Desert, and Low-Use Basins of the Mojave and Sonoran Deserts study unit, 2008-2010--Results from the California GAMA Program

    Science.gov (United States)

    Mathany, Timothy M.; Wright, Michael T.; Beuttel, Brandon S.; Belitz, Kenneth

    2012-01-01

    Groundwater quality in the 12,103-square-mile Borrego Valley, Central Desert, and Low-Use Basins of the Mojave and Sonoran Deserts (CLUB) study unit was investigated by the U.S. Geological Survey (USGS) from December 2008 to March 2010, as part of the California State Water Resources Control Board (SWRCB) Groundwater Ambient Monitoring and Assessment (GAMA) Program's Priority Basin Project (PBP). The GAMA-PBP was developed in response to the California Groundwater Quality Monitoring Act of 2001 and is being conducted in collaboration with the SWRCB and Lawrence Livermore National Laboratory (LLNL). The CLUB study unit was the twenty-eighth study unit to be sampled as part of the GAMA-PBP. The GAMA CLUB study was designed to provide a spatially unbiased assessment of untreated-groundwater quality in the primary aquifer systems, and to facilitate statistically consistent comparisons of untreated-groundwater quality throughout California. The primary aquifer systems (hereinafter referred to as primary aquifers) are defined as parts of aquifers corresponding to the perforation intervals of wells listed in the California Department of Public Health (CDPH) database for the CLUB study unit. The quality of groundwater in shallow or deep water-bearing zones may differ from the quality of groundwater in the primary aquifers; shallow groundwater may be more vulnerable to surficial contamination. In the CLUB study unit, groundwater samples were collected from 52 wells in 3 study areas (Borrego Valley, Central Desert, and Low-Use Basins of the Mojave and Sonoran Deserts) in San Bernardino, Riverside, Kern, San Diego, and Imperial Counties. Forty-nine of the wells were selected by using a spatially distributed, randomized grid-based method to provide statistical representation of the study unit (grid wells), and three wells were selected to aid in evaluation of water-quality issues (understanding wells). The groundwater samples were analyzed for organic constituents (volatile

  17. REACH SPECIFIC CHANNEL STABILIZATION BASED ON COMPREHENSIVE EVALUATION OF VALLEY FILL HISTORY, ALLUVIAL ARCHITECTURE AND GROUNDWATER HYDROLOGY IN A MOUNTAIN STREAM IN THE CENTRAL GREAT BASIN, NEVADA

    Science.gov (United States)

    Kingston meadow, located in the Toiyabe Range, is one of many wet meadow complexes threatened by rapid channel incision in the mountain ranges of the central Great Basin. Channel incision can lower the baselevel for groundwater discharge and de-water meadow complexes resulting in...

  18. Valley Fever

    Science.gov (United States)

    Valley Fever is a disease caused by a fungus (or mold) called Coccidioides. The fungi live in the soil ... from person to person. Anyone can get Valley Fever. But it's most common among older adults, especially ...

  19. Nutrient Management Programs, Nitrogen Fertilizer Practices, and Groundwater Quality in Nebraska’s Central Platte Valley (U.S., 1989–1998

    Directory of Open Access Journals (Sweden)

    Stan Daberkow

    2001-01-01

    Full Text Available Given the societal concern about groundwater pollution from agricultural sources, public programs have been proposed or implemented to change farmer behavior with respect to nutrient use and management. However, few of these programs designed to change farmer behavior have been evaluated due to the lack of detailed data over an appropriate time frame. The Central Platte Natural Resources District (CPNRD in Nebraska has identified an intensively cultivated, irrigated area with average groundwater nitrate-nitrogen (N levels about double the EPA’s safe drinking water standard. The CPNRD implemented a joint education and regulatory N management program in the mid-1980s to reduce groundwater N. This analysis reports N use and management, yield, and groundwater nitrate trends in the CPNRD for nearly 3000 continuous-corn fields from 1989 to 1998, where producers faced limits on the timing of N fertilizer application but no limits on amounts. Groundwater nitrate levels showed modest improvement over the 10 years of this analysis, falling from the 1989–1993 average of 18.9 to 18.1 mg/l during 1994–1998. The availability of N in excess of crop needs was clearly documented by the CPNRD data and was related to optimistic yield goals, irrigation water use above expected levels, and lack of adherence to commercial fertilizer application guidelines. Over the 10-year period of this analysis, producers reported harvesting an annual average of 9729 kg/ha, 1569 kg/ha (14% below the average yield goal. During 1989�1998, producers reported annually applying an average of 162.5 kg/ha of commercial N fertilizer, 15.7 kg/ha (10% above the guideline level. Including the N contribution from irrigation water, the potential N contribution to the environment (total N available less estimated crop use was estimated at 71.7 kg/ha. This is an estimate of the nitrates available for denitrification, volatilization, runoff, future soil N, and leaching to groundwater. On

  20. Eco-Hydrological Modelling of Stream Valleys

    DEFF Research Database (Denmark)

    Johansen, Ole

    Predicting the effects of hydrological alterations on terrestrial stream valley ecosystems requires multidisciplinary approaches involving both engineers and ecologists. Groundwater discharge in stream valleys and other lowland areas support a number of species rich ecosystems, and their protection...... is prioritised worldwide. Protection requires improved knowledge on the functioning of these ecosystems and especially the linkages between vegetation, groundwater discharge and water level conditions are crucial for management applications. Groundwater abstraction affects catchment hydrology and thereby also...... groundwater discharge. Numerical hydrological modelling has been widely used for evaluation of sustainable groundwater resources and effects of abstraction, however, the importance of local scale heterogeneity becomes increasingly important in the assessment of local damage to these groundwater dependent...

  1. Numerical Simulation of Inter-basin Groundwater Flow into Northern Yucca Flat, Nevada National Security Site, Using the Death Valley Regional Flow System Model

    Energy Technology Data Exchange (ETDEWEB)

    Pohlmann Karl,Ye Ming

    2012-03-01

    Models of groundwater flow for the Yucca Flat area of the Nevada National Security Site (NNSS) are under development by the U.S. Department of Energy (DOE) for corrective action investigations of the Yucca Flat-Climax Mine Corrective Action Unit (CAU). One important aspect of these models is the quantity of inter-basin groundwater flow from regional systems to the north. This component of flow, together with its uncertainty, must be properly accounted for in the CAU flow models to provide a defensible regional framework for calculations of radionuclide transport that will support determinations of the Yucca Flat-Climax Mine contaminant boundary. Because characterizing flow boundary conditions in northern Yucca Flat requires evaluation to a higher level of detail than the scale of the Yucca Flat-Climax Mine CAU model can efficiently provide, a study more focused on this aspect of the model was required.

  2. Maintenance action readiness assessment plan for White Oak Creek and Melton Branch Weir Stilling Pool cleanout at Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    1995-08-01

    This Readiness Assessment Plan has been prepared to document operational readiness for the following maintenance action: (1) removal of sediment from the White Oak Creek and Melton Branch Weir Stilling Pools and (2) disposal of the radiologically contaminated sediment in another location upstream of the weirs in an area previously contaminated by stream overflow from Melton Branch in Waste Area Grouping 2 (WAG) at Oak Ridge National Laboratory. This project is being performed as a maintenance action rather than an action under the Comprehensive Environmental Response, Compensation, and Liability Act because the risk to human health and environment is well below the US Environmental Protection Agency's level of concern. The decision to proceed as a maintenance action was documented by an interim action proposed plan, which is included in the administrative record. The administrative record is available for review at the US Department of Energy Information Resource Center, 105 Broadway Avenue, Oak Ridge, Tennessee 37830

  3. Assessing the recharge process and importance of montane water to adjacent tectonic valley-plain groundwater using a ternary end-member mixing analysis based on isotopic and chemical tracers

    Science.gov (United States)

    Peng, Tsung-Ren; Zhan, Wen-Jun; Tong, Lun-Tao; Chen, Chi-Tsun; Liu, Tsang-Sen; Lu, Wan-Chung

    2018-03-01

    A study in eastern Taiwan evaluated the importance of montane water contribution (MC) to adjacent valley-plain groundwater (VPG) in a tectonic suture zone. The evaluation used a ternary natural-tracer-based end-member mixing analysis (EMMA). With this purpose, VPG and three end-member water samples of plain precipitation (PP), mountain-front recharge (MFR), and mountain-block recharge (MBR) were collected and analyzed for stable isotopic compositions (δ 2H and δ 18O) and chemical concentrations (electrical conductivity (EC) and Cl-). After evaluation, Cl- is deemed unsuitable for EMMA in this study, and the contribution fractions of respective end members derived by the δ 18O-EC pair are similar to those derived by the δ 2H-EC pair. EMMA results indicate that the MC, including MFR and MBR, contributes at least 70% (679 × 106 m3 water volume) of the VPG, significantly greater than the approximately 30% of PP contribution, and greater than the 20-50% in equivalent humid regions worldwide. The large MC is attributable to highly fractured strata and the steep topography of studied catchments caused by active tectonism. Furthermore, the contribution fractions derived by EMMA reflect the unique hydrogeological conditions in the respective study sub-regions. A region with a large MBR fraction is indicative of active lateral groundwater flow as a result of highly fractured strata in montane catchments. On the other hand, a region characterized by a large MFR fraction may possess high-permeability stream beds or high stream gradients. Those hydrogeological implications are helpful for water resource management and protection authorities of the studied regions.

  4. Groundwater-quality data for a treated-wastewater plume near the Massachusetts Military Reservation, Ashumet Valley, Cape Cod, Massachusetts, 2006-08

    Science.gov (United States)

    Savoie, Jennifer G.; LeBlanc, Denis R.; Fairchild, Gillian M.; Smith, Richard L.; Kent, Douglas B.; Barber, Larry B.; Repert, Deborah A.; Hart, Charles P.; Keefe, Steffanie H.; Parsons, Luke A.

    2012-01-01

    A plume of contaminated groundwater extends from former disposal beds at the Massachusetts Military Reservation's wastewater-treatment plant toward Ashumet Pond, coastal ponds, and Vineyard Sound, Cape Cod, Massachusetts. Treated sewage-derived wastewater was discharged to the rapid-infiltration beds for nearly 60 years before the disposal site was moved to a different location in December 1995. Water-quality samples were collected from monitoring wells, multilevel samplers, and profile borings to characterize the nature and extent of the contaminated groundwater and to observe the water-quality changes after the wastewater disposal ceased. Data are presented here for water samples collected in 2007 from 394 wells (at 121 well-cluster locations) and 780 multilevel-sampler ports (at 42 locations) and in 2006-08 at 306 depth intervals in profile borings (at 20 locations) in and near the treated-wastewater plume. Analyses of these water samples for field parameters (specific conductance, pH, dissolved oxygen and phosphate concentrations, and alkalinity); absorbance of ultraviolet/visible light; and concentrations of nitrous oxide, dissolved organic carbon, methylene blue active substances, selected anions and nutrients, including nitrate and ammonium, and selected inorganic solutes, including cations, anions, and minor elements, are presented in tabular format. The natural restoration of the sand and gravel aquifer after removal of the treated-wastewater source, along with interpretations of the water quality in the treated-wastewater plume, have been documented in several published reports that are listed in the references.

  5. Ground-water hydrology and subsurface migration of radioisotopes at a low-level solid radioactive-waste disposal site, West Valley, New York

    International Nuclear Information System (INIS)

    Prudic, D.E.; Randall, A.D.

    1979-01-01

    Burial trenches for disposal of solid radioactive waste at West Valley, NY, are excavated in till that has very low hydraulic conductivity (about 5 x 10 -8 centimeters per second). Fractures and root tubes with chemically oxidized and/or reduced soil in their walls extend 3 to 4.5 meters below natural land surface. Preliminary simulations of pressure heads with a digital model suggest that hydraulic conductivity is an order of magnitude greater in the fractured till near land surface than at greater depth. Hydraulic gradients are predominantly downward, even beneath small valleys. The upper part of a body of underlying lacustrine silt is unsaturated; in the lower, saturated part, slow lateral flow may occur. In the older trenches, water began to build up in 1971, overflowed briefly in 1975, and was pumped out in 1975--76. Water levels rose abruptly during major rainstorms in mid-1975, indicating rapid infiltration through cracks in the cover material. The new trenches have maintained low, stable water levels, perhaps because of thicker, more compact cover and less waste settlement; pressure heads near these trenches are low, locally approaching zero, perhaps because of slight infiltration and limited near-surface storage. Peak tritium concentrations in test-hole cores (generally 10 -5 to 10 -3 microcuries per milliliter) were found within 3 meters of land surface and are attributed to surface contamination. Concentrations declined rapidly with depth within the fractured till; secondary peaks found at about 9 meters in three holes are attributed to lateral migration from trenches. Other radioisotopes were detected only near land surface. Samples from the walls of shallow fractures revealed no accumulation of radioisotopes

  6. Ground-water hydrology and subsurface migration of radioisotopes at a low-level solid radioactive-waste disposal site, West Valley, New York

    Science.gov (United States)

    Prudic, David E.; Randall, Allan D.

    1977-01-01

    Burial trenches for disposal of solid radioactive waste at West Valley, N.Y., are excavated in till that has very low hydraulic conductivity (about 5 x 10 to the minus 8th power centimeters per second). Fractures and root tubes with chemically oxidized and (or) reduced soil in their walls extend to 3 to 4.5 meters below natural land surface. Preliminary simulations of pressure heads with a digital model suggest that hydraulic conductivity is an order of magnitude greater in the fractured till near land surface than at greater depth. Hydraulic gradients are predominantly downward, even beneath small valleys. The upper part of a body of underlying lacustrine silt is unsaturated; in the lower, saturated part, slow lateral flow may occur. In the older trenches, water began to build up in 1971, overflowed briefly in 1975, and was pumped out in 1975-76. Water levels rose abruptly during major rainstorms in mid-1975, indicating rapid infiltration through cracks in the cover material. The new trenches have maintained low, stable water levels, perhaps because of thicker, more compact cover and less waste settlement; pressure heads near these trenches are low, locally approaching zero, perhaps because of slight infiltration and limited near-surface storage. Peak tritium concentrations in test-hole cores (generally 0.00001 to 0.001 microcuries per milliliter) were found within 3 meters of land surface and are attributed to surface contamination. Concentrations declined rapidly with depth within the fractured till; secondary peaks found at about 9 meters in three holes are attributed to lateral migration from trenches. Other radioisotopes were detected only near land surface. Samples from the walls of shallow fractures revealed no accumulation of radioisotopes. (Woodard-USGS)

  7. Ground-water hydrology and subsurface migration of radioisotopes at a low-level solid radioactive-waste disposal site, West Valley, New York

    International Nuclear Information System (INIS)

    Prudic, D.E.; Randall, A.D.

    1977-07-01

    Burial trenches for disposal of solid radioactive waste at West Valley, N.Y. are excavated in till that has very low hydraulic conductivity (about 5 x 10 -8 centimeters per second). Fractures and root tubes with chemically oxidized and(or) reduced soil in their walls extend 3 to 4.5 meters below natural land surface. Preliminary simulations of pressure heads with a digital model suggest that hydraulic conductivity is an order of magnitude greater in the fractured till near land surface than at greater depth. Hydraulic gradients are predominantly downward, even beneath small valleys. The upper part of a body of underlying lacustrine silt is unsaturated; in the lower, saturated part, slow lateral flow may occur. In the older trenches, water began to build up in 1971, overflowed briefly in 1975, and was pumped out in 1975--76. Water levels rose abruptly during major rainstorms in mid-1975, indicating rapid infiltration through cracks in the cover material. The new trenches have maintained low, stable water levels, perhaps because of thicker, more compact cover and less waste settlement; pressure heads near these trenches are low, locally approaching zero, perhaps because of slight infiltration and limited near-surface storage. Peak tritium concentrations in test-hole cores (generally 10 -5 to 10 -3 microcuries per milliliter) were found within 3 meters of land surface and are attributed to surface contamination. Concentrations declined rapidly with depth within the fractured till; secondary peaks found at about 9 meters in three holes are attributed to lateral migration from trenches. Other radioisotopes were detected only near land surface. Samples from the walls of shallow fractures revealed no accumulation of radioisotopes

  8. Limits to global groundwater consumption

    Science.gov (United States)

    de Graaf, I.; Van Beek, L. P.; Sutanudjaja, E.; Wada, Y.; Bierkens, M. F.

    2016-12-01

    Groundwater is the largest accessible freshwater resource worldwide and is of critical importance for irrigation, and so for global food security. For many regions of the world where groundwater abstraction exceeds groundwater recharge, persistent groundwater depletion occurs. A direct consequence of depletion is falling groundwater levels, reducing baseflows to rivers, harming ecosystems. Also, pumping costs increase, wells dry up and land subsidence can occur. Water demands are expected to increase further due to growing population, economic development and climate change, posing the urgent question how sustainable current water abstractions are worldwide and where and when these abstractions approach conceivable limits with all the associated problems. Here, we estimated past and future trends (1960-2050) in groundwater levels resulting from changes in abstractions and climate and predicted when limits of groundwater consumption are reached. We explored these limits by predicting where and when groundwater levels drop that low that groundwater becomes unattainable for abstractions and how river flows are affected. Water availabilities, abstractions, and lateral groundwater flows are simulated (5 arcmin. resolution) using a coupled version of the global hydrological model PCR-GLOBWB and a groundwater model based on MODFLOW. The groundwater model includes a parameterization of the worlds confined and unconfined aquifer systems, needed for a realistic simulation of groundwater head dynamics. Results show that, next to the existing regions experiencing groundwater depletion (like India, Pakistan, Central Valley) new regions will develop, e.g. Southern Europe, the Middle East, and Africa. Using a limit that reflects present-day feasibility of groundwater abstraction, we estimate that in 2050 groundwater becomes unattainable for 20% of the global population, mainly in the developing countries and pumping cost will increase significantly. Largest impacts are found

  9. Natural uranium and strontium isotope tracers of water sources and surface water-groundwater interactions in arid wetlands: Pahranagat Valley, Nevada, USA

    Science.gov (United States)

    Paces, James B.; Wurster, Frederic C.

    2014-01-01

    Near-surface physical and chemical process can strongly affect dissolved-ion concentrations and stable isotope compositions of water in wetland settings, especially under arid climate conditions. In contrast, heavy radiogenic isotopes of strontium (87Sr/86Sr) and uranium (234U/238U) remain largely unaffected and can be used to help identify unique signatures from different sources and quantify end-member mixing that would otherwise be difficult to determine. The utility of combined Sr and U isotopes are demonstrated in this study of wetland habitats on the Pahranagat National Wildlife Refuge, which depend on supply from large-volume springs north of the Refuge, and from small-volume springs and seeps within the Refuge. Water budgets from these sources have not been quantified previously. Evaporation, transpiration, seasonally variable surface flow, and water management practices complicate the use of conventional methods for determining source contributions and mixing relations. In contrast, 87Sr/86Sr and 234U/238U remain unfractionated under these conditions, and compositions at a given site remain constant. Differences in Sr- and U-isotopic signatures between individual sites can be related by simple two- or three-component mixing models. Results indicate that surface flow constituting the Refuge’s irrigation source consists of a 65:25:10 mixture of water from two distinct regionally sourced carbonate aquifer springs, and groundwater from locally sourced volcanic aquifers. Within the Refuge, contributions from the irrigation source and local groundwater are readily determined and depend on proximity to those sources as well as water management practices.

  10. Valley development on Hawaiian volcanoes

    International Nuclear Information System (INIS)

    Baker, V.R.; Gulick, V.C.

    1987-01-01

    Work in progress on Hawaiian drainage evolution indicates an important potential for understanding drainage development on Mars. Similar to Mars, the Hawaiian valleys were initiated by surface runoff, subsequently enlarged by groundwater sapping, and eventually stabilized as aquifers were depleted. Quantitative geomorphic measurements were used to evaluate the following factors in Hawaiian drainage evolution: climate, stream processes, and time. In comparing regions of similar climate, drainage density shows a general increase with the age of the volcani island. With age and climate held constant, sapping dominated valleys, in contrast to runoff-dominated valleys, display the following: lower drainage densities, higher ratios of valley floor width to valley height, and more positive profile concavities. Studies of stream junction angles indicate increasing junction angles with time on the drier leeward sides of the major islands. The quantitative geomorphic studies and earlier field work yielded important insights for Martian geomorphology. The importance of ash mantling in controlling infiltration on Hawaii also seems to apply to Mars. The Hawaiian valley also have implications for the valley networks of Martian heavily cratered terrains

  11. Assessment of groundwater pollution by nitrates using intrinsic ...

    African Journals Online (AJOL)

    The present article targets the determination of the vulnerability of groundwater reservoirs of a climatic Mediterranean region (Nil valley region, Jijel). The excessive use of fertilizers in agriculture has been the main reason behind the increase of the Nil valley groundwater pollution with nitrates (Jijel, North-East Algeria).

  12. Using water chemistry, isotopes and microbiology to evaluate groundwater sources, flow paths and geochemical reactions in the Death Valley flow system, USA

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, James M.; Hershey, Ronald L. [Desert Research Institute, 2215 Raggio Pwky, Reno, NV, USA 89512 (United States); Moser, Duane P.; Fisher, Jenny C.; Reihle, Jessica; Wheatley, Alexandra [Desert Research Institute, 755 E. Flamingo Rd, Las Vegas, NV, USA 89130 (United States); Baldino, Cristi; Weissenfluh, Darrick [US Fish and Wildlife Service, Ash Meadows NWR, Amargosa Valley, NV, USA 89020 (United States)

    2013-07-01

    Springs of Ash Meadows and Furnace Creek (near or in Death Valley, CA) have nearly constant flow, temperature, chemistry, and similar δ{sup 2}H and δ{sup 18}O signatures. These factors indicate shared water sources and/or analogous geochemical reactions along similar flow paths. DNA-based (16S rRNA gene) microbial diversity assessments further illuminate these relationships. Whereas, all Ash Meadows springs share related archaea populations, variations in carbon-14 (Crystal Spring) and strontium isotopes, Na{sup +}, SO{sub 4}{sup 2-}, and methane concentrations (Big Spring), correspond with microbial differences within and between the two discharge areas. Similar geochemical signatures linking Ash Meadows and Furnace Creek springs appear to support a distinct end member at Big Spring in Ash Meadows, which is also supported by coincident enrichment in microbial methanogens and methanotrophs. Conversely, DNA libraries from a deep carbonate well (878 m) located between Ash Meadows and Furnace Creek (BLM-1), indicate no shared microbial diversity between Ash Meadows or Furnace Creek springs. (authors)

  13. Ground-water hydrology and subsurface migration of radionuclides at a commercial radioactive-waste burial site, West Valley, Cattaraugus County, New York

    Science.gov (United States)

    Prudic, David E.

    1986-01-01

    Low-level radioactive wastes were buried from 1963-75 in trenches excavated in a clay-rich till about 28 meters thick. Beneath the till is a lacustrine sequence that is unsaturated in its upper part and acts as a drain to the till. The till is nearly isotropic; hydraulic conductivity ranges between 2 times 10 to the minus 8th power and 6 times 10 to the minus 8th power centimeters/sec. Fractures with oxidized walls extend as much as 5 meters below the original land surface. The fractured till is 5 to 10 times more permeable than the deeper unfractured till, as determined from computer simulations. The direction of groundwater flow in the till is predominantly downward, with an average linear pore velocity of 1 to 8 centimeters/year. Tritium migrated less than 3 meters from three trenches in the 7 to 11 years after they were completed. Carbon-14 migrated less than 1 meter, and migration of other radionuclides is apparently even less. The migration of tritium and carbon-14 occurs chiefly by diffusion. Radionuclides are far less likely to reach the surface environment by subsurface flow through the till than by seepage of trench water through the trench covers, which can occur whenever trenches become filled with water from recharge entering through cracks that form in the cover. (USGS)

  14. Water resources of Parowan Valley, Iron County, Utah

    Science.gov (United States)

    Marston, Thomas M.

    2017-08-29

    Parowan Valley, in Iron County, Utah, covers about 160 square miles west of the Red Cliffs and includes the towns of Parowan, Paragonah, and Summit. The valley is a structural depression formed by northwest-trending faults and is, essentially, a closed surface-water basin although a small part of the valley at the southwestern end drains into the adjacent Cedar Valley. Groundwater occurs in and has been developed mainly from the unconsolidated basin-fill aquifer. Long-term downward trends in groundwater levels have been documented by the U.S. Geological Survey (USGS) since the mid-1950s. The water resources of Parowan Valley were assessed during 2012 to 2014 with an emphasis on refining the understanding of the groundwater and surface-water systems and updating the groundwater budget.Surface-water discharge of five perennial mountain streams that enter Parowan Valley was measured from 2013 to 2014. The total annual surface-water discharge of the five streams during 2013 to 2014 was about 18,000 acre-feet (acre-ft) compared to the average annual streamflow of about 22,000 acre-ft from USGS streamgages operated on the three largest of these streams from the 1940s to the 1980s. The largest stream, Parowan Creek, contributes more than 50 percent of the annual surface-water discharge to the valley, with smaller amounts contributed by Red, Summit, Little, and Cottonwood Creeks.Average annual recharge to the Parowan Valley groundwater system was estimated to be about 25,000 acre-ft from 1994 to 2013. Nearly all recharge occurs as direct infiltration of snowmelt and rainfall on the Markagunt Plateau east of the valley. Smaller amounts of recharge occur as infiltration of streamflow and unconsumed irrigation water near the east side of the valley on alluvial fans associated with mountain streams at the foot of the Red Cliffs. Subsurface flow from the mountain block to the east of the valley is a significant source of groundwater recharge to the basin-fill aquifer

  15. Valley Fever

    Science.gov (United States)

    ... loss Headache Valley fever Symptoms & causes Diagnosis & treatment Advertisement Mayo Clinic does not endorse companies or products. ... a Job Site Map About This Site Twitter Facebook Google YouTube Pinterest Mayo Clinic is a not- ...

  16. Environmental isotopes investigation in groundwater of Challaghatta ...

    African Journals Online (AJOL)

    Radiogenic isotopes (3H and 14C) and stable isotope (18O) together with TDS, EC and salinity of water were used to discriminate qualitative and quantitative groundwater age, probable recharge time, flow respectively in groundwater of Challaghatta valley, Bangalore. The variations between TDS and EC values of sewage ...

  17. Compendium of ordinances for groundwater protection

    Energy Technology Data Exchange (ETDEWEB)

    1990-08-01

    Groundwater is an extremely important resource in the Tennessee Valley. Nearly two-thirds of the Tennessee Valley's residents rely, at least in part, on groundwater supplies for drinking water. In rural areas, approximately ninety-five percent of residents rely on groundwater for domestic supplies. Population growth and economic development increase the volume and kinds of wastes requiring disposal which can lead to groundwater contamination. In addition to disposal which can lead to groundwater contamination. In addition to disposal problems associated with increases in conventional wastewater and solid waste, technological advancements in recent decades have resulted in new chemicals and increased usage in agriculture, industry, and the home. Unfortunately, there has not been comparable progress in identifying the potential long-term effects of these chemicals, in managing them to prevent contamination of groundwater, or in developing treatment technologies for removing them from water once contamination has occurred. The challenge facing residence of the Tennessee Valley is to manage growth and economic and technological development in ways that will avoid polluting the groundwater resource. Once groundwater has been contaminated, cleanup is almost always very costly and is sometimes impractical or technically infeasible. Therefore, prevention of contamination -- not remedial treatment--is the key to continued availability of usable groundwater. This document discusses regulations to aid in this prevention.

  18. Report on water quality, sediment and water chemistry data for water and sediment samples collected from source areas to Melton Hill and Watts Bar reservoirs

    International Nuclear Information System (INIS)

    Tomaszewski, T.M.; Bruggink, D.J.; Nunn, D.L.

    1995-01-01

    Contamination of surface water and sediments in the Clinch River and Watts Bar Reservoir (CR/WBR) system as a result of past and present activities by the US Department of Energy (DOE) on the Oak Ridge Reservation (ORR) and also activities by non-ORR facilities are being studied by the Clinch River Environmental Restoration Program (CR-ERP). Previous studies have documented the presence of heavy metals, organics, and radionuclides in the sediments of reservoirs in the vicinity. In support of the CR-ERP, during the summer of 1991, TVA collected and evaluated water and sediment samples from swimming areas and municipal water intakes on Watts Bar Reservoir, Melton Hill Reservoir and Norris Reservoir, which was considered a source of less-contaminated reference or background data. Despite the numerous studies, until the current work documented by this report, relatively few sediment or water samples had been collected by the CR-ERP in the immediate vicinity of contaminant point sources. This work focused on water and sediment samples taken from points immediately downstream from suspected effluent point sources both on and off the ORR. In August and September, 1994, TVA sampled surface water and sediment at twelve locations in melton Hill and Watts Bar Reservoirs

  19. Design assessment for the Melton Valley Storage Tanks capacity increase at Oak Ridge National Laboratory under the Federal Facility Agreement, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    1995-11-01

    This project was initiated to find ways to increase storage capacity for the liquid low-level waste (LLLW) system at the Oak Ridge National Laboratory and satisfy the Federal Facility Agreement (FFA) requirement for the transfer of LLW from existing tank systems not in full FFA compliance

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

    Science.gov (United States)

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

    2017-12-01

    Groundwater is a vital resource for California, providing between 30-60% of the state's water supply. Recent emphasis on groundwater sustainability has induced a push to characterize recharge rates and residence times for high priority aquifers, including most aquifers in California's Central Valley. Flows in almost all rivers from the western Sierra to the Central Valley are controlled by dams, altering natural flow patterns and recharge to local aquifers. In eastern Sacramento, unconfined and confined shallow aquifers (depth BGS. Variation in groundwater age in the vertical and horizontal directions are used to determine groundwater flow path and velocity. These data are then used to calculate residence time of groundwater in the unconfined and confined aquifer systems for the Central Valley in eastern Sacramento. Applying groundwater age tracers can benefit future compliance metrics of the California Sustainable Groundwater Resources Act (SGMA), by quantifying river seepage rates and impacts of groundwater management on surface water resources. 1Moran et al., UCRL-TR-203258, 2004.

  1. Effect of the Irrigation Canal Network on Surface and Groundwater Interactions in the Lower Valley of the Cachapoal River, Chile Efecto de la Red de Canales de Riego en las Interacciones de Agua Superficial y Subterránea en la Parte Baja del Valle Del Río Cachapoal, Chile

    Directory of Open Access Journals (Sweden)

    José Luis Arumí

    2009-03-01

    Full Text Available Agricultural production of high value crops in Chile's Central Valley is highly dependent on surface and groundwater resources. They are connected and together form an integrated hydrological system, the individual components of which have to be studied. This research is addressed to answering two questions: 1 to what extent do irrigation and canal seepage contribute to groundwater recharge and 2 what is the influence of the interactions between the Cachapoal River and ground water. The study was carried out from 2003 to 2007 in Peumo Valley (34.3° S, 71.3° W. In winter, the irrigation canal network intercepts and diverts surface runoff, which flows to flat areas and recharges groundwater. In summer, infiltration from the canals recharges the aquifer directly and partially compensates for water uptake from plants and evaporation. The effects of both interactions keep groundwater at a relatively constant level over the whole year. The water balance of the valley is strongly affected by agricultural practices, groundwater recharge mainly originating from irrigation loss (22% and canal seepage (52%. It is important to know how management decisions, such as change in irrigation practices or canal lining, can affect the hydrological system and agricultural production within the valley.La producción agrícola de exportación en la Zona Central de Chile es altamente dependiente de los recursos hídricos superficiales y subterráneos, los que a su vez están conectados formando un solo sistema hidrológico a través de procesos que no están bien estudiados. Esta investigación apunta a responder dos preguntas de trabajo: 1 Entender el efecto de las filtraciones de los canales de riego en la recarga de los sistemas de aguas subterráneas; y 2 Identificar los patrones de interacción entre las aguas subterráneas y superficiales en el valle de Peumo. Este estudio se ejecutó entre los años 2003 y 2007 en el valle de Peumo, localizado en a Tercera

  2. An overview of integrated remote sensing and GIS for groundwater mapping in Egypt

    OpenAIRE

    Salwa Farouk Elbeih

    2015-01-01

    Groundwater is considered the major portion of the world’s freshwater resources. One of the main challenges facing the sustainable development of Egypt is the need for better management of its limited fresh water resources. Groundwater exists in the Nile Valley, Nile Delta, Western Desert Oases, and Sinai Peninsula. Hydrogeological mapping of groundwater resources is one of the main tools for the controlled development of groundwater resources. Remotely sensed surface indicators of groundwate...

  3. Effect of Groundwater Abstraction on Fen Ecosystems

    DEFF Research Database (Denmark)

    Johansen, Ole; Pedersen, Morten Lauge; Jensen, Jacob Birk

    2011-01-01

    within a distance of 1.5 km to a planned well field. In the river valley the interaction between groundwater and surface water is strongly affected by low permeable sediments. These sediments reduce the direct discharge to the river and have a large impact on the functioning and presence of the rich fen......Quantifying the effects of groundwater abstraction on fen ecosystems located in discharge areas can be complicated. The water level in fens is close to the terrain surface most of the year and it is controlled by a relatively constant groundwater exfiltration. It is difficult to measure...... the exfiltration fluxes and thus water level data is typically used to evaluate if the ecosystem is affected. The paper presents collected data and analysis from a case study, where the hydrological effect of groundwater abstraction on rich fens and springs in a Danish river valley has been studied. The natural...

  4. Mechanisms for pressurized groundwater outflow channels, implications for Mars

    NARCIS (Netherlands)

    Marra, Wouter; Kleinhans, Maarten|info:eu-repo/dai/nl/217675123; Hauber, E.; McLelland, Stuart J.; Murphy, Brendan J.; Parsons, Daniel R.; Conway, Susan J.

    2014-01-01

    Various valleys on Mars show evidence for extensive fluvial activity in the past. The largest valleys on Mars are several tens to hundreds of kilometers wide and are thought to have originated from outflow of pressurized groundwater. However, exact mechanisms of these processes are lacking, which

  5. Water resources of No Name Valley, Colville Indian Reservation, Washington

    Science.gov (United States)

    Cline, Denzel R.

    1978-01-01

    No Name Creek valley is a trough cut in granitic bedrock in north-central Washington. A low topographic divide in the northern third of the valley separates it into the No Name Creek basin on the south and Omak Creek basin on the north. Omak Creek is the larger stream and enters the valley through a narrow gorge in the eastern granite wall. Partly filled with unconsolidated sand, gravel, and silt to depths as great as 163 feet, the valley contains a ground-water reservoir which supplies four irrigation wells and several domestic-supply wells. The ground-water reservoir also feeds springs which give rise to No Name Creek, and it contributes some water to Omak Creek to the north. Under conditions of the pre-1976 development the ground-water divide was naturally about 3,000 feet north of Omak Creek gorge, and about 580 acre-feet of leakage from Omak Creek recharges the No Name Creek ground-water reservoir. By 1977, ground-water withdrawal of 994 acre-feet per year in No Name Creek basin had caused the ground-water divide to shift to a position about 4,000 feet north of the topographic divide. This increased the drainage area contributing to the No Name Creek ground-water reservoir for about three months so that during a year of normal flow a total of about 600 acre-feet of leakage from Omak Creek can be captured. It is postulated that as much as 1,100 acre-feet per year can be pumped in the central part of the reservoir. This pumpage would cause the ground-water divide to shift farther north, resulting in the capture of additional recharge from Omak Creek; the total leakage would be about 700 acre-feet per year. (Woodard-USGS)

  6. Monitoring and Assessing Groundwater Impacts on Vegetation Health in Groundwater Dependent Ecosystems

    Science.gov (United States)

    Rohde, M. M.; Ulrich, C.; Howard, J.; Sweet, S.

    2017-12-01

    Sustainable groundwater management is important for preserving our economy, society, and environment. Groundwater supports important habitat throughout California, by providing a reliable source of water for these Groundwater Dependent Ecosystems (GDEs). Groundwater is particularly important in California since it supplies an additional source of water during the dry summer months and periods of drought. The drought and unsustainable pumping practices have, in some areas, lowered groundwater levels causing undesirable results to ecosystems. The Sustainable Groundwater Management Act requires local agencies to avoid undesirable results in the future, but the location and vulnerabilities of the ecosystems that depend on groundwater and interconnected surface water is often poorly understood. This presentation will feature results from a research study conducted by The Nature Conservancy and Lawrence Berkeley National Laboratory that investigated how changes in groundwater availability along an interconnected surface water body can impact the overall health of GDEs. This study was conducted in California's Central Valley along the Cosumnes River, and situated at the boundary of a high and a medium groundwater basin: South American Basin (Sacramento Hydrologic Region) and Cosumnes Basin (San Joaquin Hydrologic Region). By employing geophysical methodology (electrical resistivity tomography) in this study, spatial changes in groundwater availability were determined under groundwater-dependent vegetation. Vegetation survey data were also applied to this study to develop ecosystem health indicators for groundwater-dependent vegetation. Health indicators for groundwater-dependent vegetation were found to directly correlate with groundwater availability, such that greater availability to groundwater resulted in healthier vegetation. This study provides a case study example on how to use hydrological and biological data for setting appropriate minimum thresholds and

  7. Water availability and land subsidence in the Central Valley, California, USA

    Science.gov (United States)

    Faunt, Claudia; Sneed, Michelle; Traum, Jonathan A.; Brandt, Justin

    2016-01-01

    The Central Valley in California (USA) covers about 52,000 km2 and is one of the most productive agricultural regions in the world. This agriculture relies heavily on surface-water diversions and groundwater pumpage to meet irrigation water demand. Because the valley is semi-arid and surface-water availability varies substantially, agriculture relies heavily on local groundwater. In the southern two thirds of the valley, the San Joaquin Valley, historic and recent groundwater pumpage has caused significant and extensive drawdowns, aquifer-system compaction and subsidence. During recent drought periods (2007–2009 and 2012-present), groundwater pumping has increased owing to a combination of decreased surface-water availability and land-use changes. Declining groundwater levels, approaching or surpassing historical low levels, have caused accelerated and renewed compaction and subsidence that likely is mostly permanent. The subsidence has caused operational, maintenance, and construction-design problems for water-delivery and flood-control canals in the San Joaquin Valley. Planning for the effects of continued subsidence in the area is important for water agencies. As land use, managed aquifer recharge, and surface-water availability continue to vary, long-term groundwater-level and subsidence monitoring and modelling are critical to understanding the dynamics of historical and continued groundwater use resulting in additional water-level and groundwater storage declines, and associated subsidence. Modeling tools such as the Central Valley Hydrologic Model, can be used in the evaluation of management strategies to mitigate adverse impacts due to subsidence while also optimizing water availability. This knowledge will be critical for successful implementation of recent legislation aimed toward sustainable groundwater use.

  8. Water availability and land subsidence in the Central Valley, California, USA

    Science.gov (United States)

    Faunt, Claudia C.; Sneed, Michelle; Traum, Jon; Brandt, Justin T.

    2016-05-01

    The Central Valley in California (USA) covers about 52,000 km2 and is one of the most productive agricultural regions in the world. This agriculture relies heavily on surface-water diversions and groundwater pumpage to meet irrigation water demand. Because the valley is semi-arid and surface-water availability varies substantially, agriculture relies heavily on local groundwater. In the southern two thirds of the valley, the San Joaquin Valley, historic and recent groundwater pumpage has caused significant and extensive drawdowns, aquifer-system compaction and subsidence. During recent drought periods (2007-2009 and 2012-present), groundwater pumping has increased owing to a combination of decreased surface-water availability and land-use changes. Declining groundwater levels, approaching or surpassing historical low levels, have caused accelerated and renewed compaction and subsidence that likely is mostly permanent. The subsidence has caused operational, maintenance, and construction-design problems for water-delivery and flood-control canals in the San Joaquin Valley. Planning for the effects of continued subsidence in the area is important for water agencies. As land use, managed aquifer recharge, and surface-water availability continue to vary, long-term groundwater-level and subsidence monitoring and modelling are critical to understanding the dynamics of historical and continued groundwater use resulting in additional water-level and groundwater storage declines, and associated subsidence. Modeling tools such as the Central Valley Hydrologic Model, can be used in the evaluation of management strategies to mitigate adverse impacts due to subsidence while also optimizing water availability. This knowledge will be critical for successful implementation of recent legislation aimed toward sustainable groundwater use.

  9. Integrated management of water resources in the valley of Oued ...

    African Journals Online (AJOL)

    This study designed to analyze and evaluate the results of trend scenarios of the strategy management of water resources used in the valley of Oued-Souf, who led the region to a truly dramatic situation and almost desperate: rise of groundwater and its adverse consequences. In terms of this work, we seek a model (plan) ...

  10. Groundwater animals

    OpenAIRE

    Maurice, Louise; Bloomfield, John; Robertson, Anne; Allen, Debbie

    2010-01-01

    Groundwater animals are adapted to live in environments with no light and limited nutrients, They can provide insights into fundamental questions of evolution, ecology and biodiversity. They also have an important role to play in informing the reconstruction of past changes in geomorphology and climate, and can be used for characterising aquifers. The BGS is undertaking a systematic survey of selected areas and lithologies in the UK where groundwater animals have not been inves...

  11. Testing MODFLOW-LGR for simulating flow around Buried Quaternary valleys - synthetic test cases

    DEFF Research Database (Denmark)

    Vilhelmsen, Troels Norvin; Christensen, Steen

    In Denmark the water supply is entirely based on ground water. In some parts of the country these resources are found in buried quaternary tunnel valleys. Intensive mapping has shown that the valleys typically have a complex internal hydrogeology with multiple cut and ­fill structures. The admini......In Denmark the water supply is entirely based on ground water. In some parts of the country these resources are found in buried quaternary tunnel valleys. Intensive mapping has shown that the valleys typically have a complex internal hydrogeology with multiple cut and ­fill structures....... The administration of groundwater resources has been based on simulations using regional scale groundwater models. However, regional scale models have difficulties with accurately resolving the complex geology of the buried valleys, which bears the risk of poor model predictions of local scale effects of groundwater...... abstraction. To enable effective administration of the groundwater resources new methods need to be investigated to improve simulation of local scale flow in buried valleys that interact with surrounding regional groundwater systems. The purpose of this synthetic case study is to test the Local Grid Re...

  12. An overview of integrated remote sensing and GIS for groundwater mapping in Egypt

    Directory of Open Access Journals (Sweden)

    Salwa Farouk Elbeih

    2015-03-01

    Full Text Available Groundwater is considered the major portion of the world’s freshwater resources. One of the main challenges facing the sustainable development of Egypt is the need for better management of its limited fresh water resources. Groundwater exists in the Nile Valley, Nile Delta, Western Desert Oases, and Sinai Peninsula. Hydrogeological mapping of groundwater resources is one of the main tools for the controlled development of groundwater resources. Remotely sensed surface indicators of groundwater provide useful data where practical classical alternatives are not available. Integrated remote sensing and GIS are widely used in groundwater mapping. Locating potential groundwater targets is becoming more convenient, cost effective than invasive methods and efficient with the advent of a number of satellite imagery. The nature of remote sensing-based groundwater exploration is to delineate all possible features connected with localization of groundwater. Data, driven out of remote sensing, support decisions related to sustainable development and groundwater management.

  13. Food supply reliance on groundwater

    Science.gov (United States)

    Dalin, Carole; Puma, Michael; Wada, Yoshihide; Kastner, Thomas

    2016-04-01

    Water resources, essential to sustain human life, livelihoods and ecosystems, are under increasing pressure from population growth, socio-economic development and global climate change. As the largest freshwater resource on Earth, groundwater is key for human development and food security. Yet, excessive abstraction of groundwater for irrigation, driven by an increasing demand for food in recent decades, is leading to fast exhaustion of groundwater reserves in major agricultural areas of the world. Some of the highest depletion rates are observed in Pakistan, India, California Central Valley and the North China Plain aquifers. In addition, the growing economy and population of several countries, such as India and China, makes prospects of future available water and food worrisome. In this context, it is becoming particularly challenging to sustainably feed the world population, without exhausting our water resources. Besides, food production and consumption across the globe have become increasingly interconnected, with many areas' agricultural production destined to remote consumers. In this globalisation era, trade is crucial to the world's food system. As a transfer of water-intensive goods, across regions with varying levels of water productivity, food trade can save significant volumes of water resources globally. This situation makes it essential to address the issue of groundwater overuse for global food supply, accounting for international food trade. To do so, we quantify the current, global use of non-renewable groundwater for major crops, accounting for various water productivity and trade flows. This will highlight areas requiring quickest attention, exposing major exporters and importers of non-renewable groundwater, and thus help explore solutions to improve the sustainability of global food supply.

  14. Potential hydrologic characterization wells in Amargosa Valley

    International Nuclear Information System (INIS)

    Lyles, B.; Mihevc, T.

    1994-09-01

    More than 500 domestic, agricultural, and monitoring wells were identified in the Amargosa Valley. From this list, 80 wells were identified as potential hydrologic characterization wells, in support of the US Department of Energy (DOE) Underground Test Area/Remedial Investigation and Feasibility Study (UGTA/RIFS). Previous hydrogeologic studies have shown that groundwater flow in the basin is complex and that aquifers may have little lateral continuity. Wells located more than 10 km or so from the Nevada Test Site (NTS) boundary may yield data that are difficult to correlate to sources from the NTS. Also, monitoring well locations should be chosen within the guidelines of a hydrologic conceptual model and monitoring plan. Since these do not exist at this time, recompletion recommendations will be restricted to wells relatively close (approximately 20 km) to the NTS boundary. Recompletion recommendations were made for two abandoned agricultural irrigation wells near the town of Amargosa Valley (previously Lathrop Wells), for two abandoned wildcat oil wells about 10 km southwest of Amargosa Valley, and for Test Well 5 (TW-5), about 10 km east of Amargosa Valley

  15. Can Springs Cut Valleys Into Bedrock?

    Science.gov (United States)

    Lamb, M. P.; Dietrich, W. E.

    2004-12-01

    Valleys formed from groundwater sapping are thought to have a characteristic form including steep walls, flat floors, and amphitheatre-like heads. Observations of these features on Earth and Mars have led to the morphologic-based interpretation that groundwater sapping is an important valley forming process. This interpretation has significant implications for Mars in particular because it has been used to constrain Martian hydrology and the associated prospects for life. However, a mechanistic understanding of sapping erosion has only been demonstrated for granular mediums (i.e. sand). Many of the "sapping" valleys on Earth and (likely) Mars have been carved into bedrock, and the extension of previous work to bedrock erosion is unclear. To our knowledge, a process-based understanding of seepage erosion in bedrock does not exist, even though it is thought to be a first order geomorphic process on Earth and Mars. In order to address this knowledge gap, we are currently investigating Box Canyon, Idaho. Box Canyon, developed in the Snake River Plain, has many of the morphologic features often associated with sapping valleys. In addition, it was carved into basaltic bedrock and has a large spring emanating from its amphitheatre-like head, making it an ideal candidate for a sapping origin. There is currently no overland flow contribution to the canyon; however, based on mapping bedrock scours, a paleo-flood from an unknown upslope source did enter the canyon (and perhaps carved it). We present some first order hydraulic measurements, sediment transport calculations, and field observations to try and constrain the types of flows needed to carve Box Canyon. These flows could conceivably be derived from expansion of the current spring. Direct observation at the head of the canyon has not yet indicated how sapping could be responsible for the erosion of the headwall. We are using various dating techniques to constrain the timing and rate of headwall migration to constrain

  16. Hydroeconomic modeling of sustainable groundwater management

    Science.gov (United States)

    MacEwan, Duncan; Cayar, Mesut; Taghavi, Ali; Mitchell, David; Hatchett, Steve; Howitt, Richard

    2017-03-01

    In 2014, California passed legislation requiring the sustainable management of critically overdrafted groundwater basins, located primarily in the Central Valley agricultural region. Hydroeconomic modeling of the agricultural economy, groundwater, and surface water systems is critically important to simulate potential transition paths to sustainable management of the basins. The requirement for sustainable groundwater use by 2040 is mandated for many overdrafted groundwater basins that are decoupled from environmental and river flow effects. We argue that, for such cases, a modeling approach that integrates a biophysical response function from a hydrologic model into an economic model of groundwater use is preferable to embedding an economic response function in a complex hydrologic model as is more commonly done. Using this preferred approach, we develop a dynamic hydroeconomic model for the Kings and Tulare Lake subbasins of California and evaluate three groundwater management institutions—open access, perfect foresight, and managed pumping. We quantify the costs and benefits of sustainable groundwater management, including energy pumping savings, drought reserve values, and avoided capital costs. Our analysis finds that, for basins that are severely depleted, losses in crop net revenue are offset by the benefits of energy savings, drought reserve value, and avoided capital costs. This finding provides an empirical counterexample to the Gisser and Sanchez Effect.

  17. Isotope and chemical tracers in groundwater hydrology

    International Nuclear Information System (INIS)

    Kendall, C.; Stewart, M.K.; Morgenstern, U.; Trompetter, V.

    1999-01-01

    The course sessions cover: session 1, Fundamentals of stable and radioactive isotopes; session 2, Stable oxygen and hydrogen isotopes in hydrology: background, examples, sampling strategy; session 3, Catchment studies using oxygen and hydrogen isotopes: background - the hydrologic water balance, evapotranspiration - the lion's share, runoff generation - new water/old water fractions, groundwater recharge - the crumbs; session 4, Isotopes in catchment hydrology: survey of applications, future developments; session 5, Applications of tritium in hydrology: background and measurement, interpretation, examples; session 6, Case studies using mixing models: Hutt Valley groundwater system, an extended mixing model for simulating tracer transport in the unsaturated zone; session 7, Groundwater dating using CFC concentrations: background, sampling and measurement, use and applications; session 8, Groundwater dating with carbon-14: background, sampling and measurement, use and applications; session 9, NZ case studies: Tauranga warm springs, North Canterbury Plains groundwater; session 10, Stable carbon and nitrogen isotopes: background and examples, biological applications of C-N-S isotopes; session 11, New developments in isotope hydrology: gas isotopes, compound specific applications, age dating of sediments etc; session 12, NZ case studies: North Canterbury Plains groundwater (continued), Waimea Plains groundwater. (author). refs., figs

  18. Groundwater Potential

    African Journals Online (AJOL)

    big timmy

    INTEGRATION OF HYDROGEOPHYSICAL AND REMOTE SENSING DATA IN THE. ASSESSMENT OF GROUNDWATER POTENTIAL OF THE BASEMENT COMPLEX. TERRAIN OF EKITI STATE, SOUTHWESTERN NIGERIA. 1. 2. 3. 4. Bayowa O.G., Olorunfemi M.O., Akinluyi F.O., and Ademilua O.L. 1Department of Earth ...

  19. Geology and ground-water resources of Dane County, Wisconsin

    Science.gov (United States)

    Cline, Denzel R.

    1965-01-01

    The purpose of the ground-water investigation of Dane County, Wis., was to determine the occurrence, movement, quantity, quality, and availability of ground water in the unconsolidated deposits and the underlying bedrock. The relationships between ground water and surface water were studied in general in Dane County and in detail in the Madison metropolitan area. An analysis was made of the hydrologic system of the Yahara River valley and of the effects of ground-water pumpage on that system.

  20. Haemoragisk Rift Valley Fever

    DEFF Research Database (Denmark)

    Fabiansen, Christian; Thybo, Søren

    2007-01-01

    A case of fatal hemorrhagic Rift Valley fever during an epidemic in Kenya's North Eastern Province in January 2007 is described.......A case of fatal hemorrhagic Rift Valley fever during an epidemic in Kenya's North Eastern Province in January 2007 is described....

  1. Deep groundwater quantity and quality in the southwestern US

    Science.gov (United States)

    Kang, M.; Ayars, J. E.; Jackson, R. B.

    2017-12-01

    Groundwater demands are growing in many arid regions and adaptation through the use of non-traditional resources during extreme droughts is increasingly common. One such resource is deep groundwater, which we define as deeper than 300 m and up to several kilometer-depths. Although deep groundwater has been studied in the context of oil and gas, geothermal, waste disposal, and other uses, it remains poorly characterized, especially for the purposes of human consumption and irrigation uses. Therefore, we evaluate deep groundwater quantity and quality within these contexts. We compile and analyze data from water management agencies and oil and gas-based sources for the southwestern US, with a detailed look at California's Central Valley. We also use crop tolerance thresholds to evaluate deep groundwater quality for irrigation purposes. We find fresh and usable groundwater volume estimates in California's Central Valley to increase by three- and four-fold respectively when depths of up to 3 km are considered. Of the ten basins in the southwestern US with the most data, we find that the Great Basin has the greatest proportions of fresh and usable deep groundwater. Given the potentially large deep groundwater volumes, it is important to characterize the resource, guard against subsidence where extracted, and protect it for use in decades and centuries to come.

  2. Groundwater flood or groundwater-induced flood?

    OpenAIRE

    Robins, N.S.; Finch, J.W.

    2012-01-01

    A number of ‘groundwater flood’ events have been recorded over the Chalk aquifer in southern England since the 1994 occurrence at Chichester, Sussex. Reporting of this event and subsequent groundwater floods indicates that there are two types of groundwater flood event. Type 1 is the true groundwater flood in which the water table elevation rises above the ground elevation, and Type 2 occurs when intense groundwater discharge via bourne springs and highly permeable shallow horizons discharges...

  3. West Valley Demonstration Project site environmental report, calendar year 1997

    Energy Technology Data Exchange (ETDEWEB)

    None

    1998-06-01

    This report represents a single, comprehensive source of off-site and on-site environmental monitoring data collected during 1997 by environmental monitoring personnel for the West Valley Demonstration Project (WVDP), West Valley, New York. The environmental monitoring program and results are discussed in the body of this report. The monitoring data are presented in the appendices. The data collected provide an historical record of radionuclide and radiation levels from natural and manmade sources in the survey area and document the quality of the groundwater on and around the WVDP and the quality of the air and water discharged by the WVDP.

  4. West Valley Demonstration Project site environmental report calendar year 1998

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-06-01

    This report represents a single, comprehensive source of off-site and on-site environmental monitoring data collected during 1998 by environmental monitoring personnel for the West Valley Demonstration Project (WVDP), West Valley, New York. The environmental monitoring program and results are discussed in the body of this report. The monitoring data are presented in the appendices. The data collected provide an historical record of radionuclide and radiation levels from natural and manmade sources in the survey area and document the quality of the groundwater on and around the WVDP and the quality of the air and water discharged by the WVDP.

  5. West Valley Demonstration Project site environmental report, calendar year 1999

    Energy Technology Data Exchange (ETDEWEB)

    None Available

    2000-06-01

    This report represents a single, comprehensive source of off-site and on-site environmental monitoring data collected during 1999 by environmental monitoring personnel for the West Valley Demonstration Project (WVDP), West Valley, New York. The environmental monitoring program and results are discussed in the body of this report. The monitoring data are presented in the appendices. The data collected provide an historical record of radionuclide and radiation levels from natural and manmade sources in the survey area and document the quality of the groundwater on and around the WVDP and the quality of the air and water discharged by the WVDP.

  6. West Valley Demonstration Project site environmental report calendar year 1998

    International Nuclear Information System (INIS)

    1999-01-01

    This report represents a single, comprehensive source of off-site and on-site environmental monitoring data collected during 1998 by environmental monitoring personnel for the West Valley Demonstration Project (WVDP), West Valley, New York. The environmental monitoring program and results are discussed in the body of this report. The monitoring data are presented in the appendices. The data collected provide an historical record of radionuclide and radiation levels from natural and manmade sources in the survey area and document the quality of the groundwater on and around the WVDP and the quality of the air and water discharged by the WVDP

  7. Hydrogeologic framework of the Santa Clara Valley, California

    Science.gov (United States)

    Hanson, Randall T.

    2015-01-01

    The hydrologic framework of the Santa Clara Valley in northern California was redefined on the basis of new data and a new hydrologic model. The regional groundwater flow systems can be subdivided into upper-aquifer and lower-aquifer systems that form a convergent flow system within a basin bounded by mountains and hills on three sides and discharge to pumping wells and the southern San Francisco Bay. Faults also control the flow of groundwater within the Santa Clara Valley and subdivide the aquifer system into three subregions.After decades of development and groundwater depletion that resulted in substantial land subsidence, Santa Clara Valley Water District (SCVWD) and the local water purveyors have refilled the basin through conservation and importation of water for direct use and artificial recharge. The natural flow system has been altered by extensive development with flow paths toward major well fields. Climate has not only affected the cycles of sedimentation during the glacial periods over the past million years, but interannual to interdecadal climate cycles also have affected the supply and demand components of the natural and anthropogenic inflows and outflows of water in the valley. Streamflow has been affected by development of the aquifer system and regulated flow from reservoirs, as well as conjunctive use of groundwater and surface water. Interaquifer flow through water-supply wells screened across multiple aquifers is an important component to the flow of groundwater and recapture of artificial recharge in the Santa Clara Valley. Wellbore flow and depth-dependent chemical and isotopic data indicate that flow into wells from multiple aquifers, as well as capture of artificial recharge by pumping of water-supply wells, predominantly is occurring in the upper 500 ft (152 m) of the aquifer system. Artificial recharge represents about one-half of the inflow of water into the valley for the period 1970–1999. Most subsidence is occurring below 250 ft

  8. Groundwater Waters

    Directory of Open Access Journals (Sweden)

    Ramón Llamas

    1999-10-01

    Full Text Available The groundwaters released through springs constituted a basic element for the survival and progressive development of human beings. Man came to learn how to take better advantage of these waters by digging wells, irrigation channels, and galleries. Nevertheless, these activities do not require cooperation nor the collective agreement of relatively large groups of people, as in the case of creating the necessary structures to take advantage of the resources of surfacewaters. The construction and operation of these structures was a powerful factor in the birth of an urban or civil society – the designated water civilizations. The difference between people taking advantage of groundwater, quasi-individually, and those of surface water, where people work in a group, has continued to the present day. Whereas earlier, this difference did not bring about any special problems, the technological advances of this century, especially theturbine pump, have led to a spectacular increase in the use of roundwater. This advance has significantly contributed to reducing hunger in the world and has provided potable water in developing countries. However, the almost generalized lack of planning and control in the exploitation of these groundwaters reflects that they are little or badly understood by the managers of water policy in almost every country. As such, problems have occurred which have often become exaggerated, giving rise to water-myths. These problems, though, should be addressed if the aim is the sustainable usage of surface water as well as groundwater. To counter any misconceptions and to seek solutions to the problems, distinct plans of action can be highlighted: educating the public; fomenting a system of participative management and decisive support for the communities of users of subterranean waters; integrating a sufficient number of experts in hydrology in the various water management organizations;and assuring transparency of the data on

  9. Groundwater Waters

    OpenAIRE

    Ramón Llamas; Emilio Custodio

    1999-01-01

    The groundwaters released through springs constituted a basic element for the survival and progressive development of human beings. Man came to learn how to take better advantage of these waters by digging wells, irrigation channels, and galleries. Nevertheless, these activities do not require cooperation nor the collective agreement of relatively large groups of people, as in the case of creating the necessary structures to take advantage of the resources of surfacewaters. The construction a...

  10. Groundwater systems

    OpenAIRE

    MacDonald, A.M.; Foster, S.S.D.

    2016-01-01

    Groundwater is a vulnerable resource. As schemes are developed to pump out huge quantities of water, and with the advent of particularly persistent contaminants, the resource needs to be protected and managed (see Table 2.1). Despite groundwater’s pivotal role in sustaining ecosystems and providing water supply, the resource is still poorly understood, and hence poorly managed, in many parts of the world. When things go wrong, the damage can be lasting or even permanent. For examp...

  11. Radon measurements of groundwater in Mexico

    International Nuclear Information System (INIS)

    Espinosa, G.; Golzarri, J.I.; Cortes, A.

    1991-01-01

    Radon measurement has important applications in hydrogeological studies. Specifically, radon measurement is used to determine the fluctuations of the piezometric levels in groundwater and, in some cases, the path of the water, which is one of the key parameters for evaluating hydrogeological resources. Water from springs and deep wells in the Basin of Mexico and the valley of San Luis Potosi were sampled, measured and analyzed by previous authors. In this work, a method for measuring 222 Rn in groundwater by using a passive detector is presented and the results are compared with a similar experiment performed at the same time, using a dynamic method. The aim of the work is to develop a method for detecting, evaluating and measuring the 222 Rn in groundwater by using SSNTD technology. (author)

  12. The carbon stable isotope biogeochemistry of streams, Taylor Valley, Antarctica

    International Nuclear Information System (INIS)

    Lyons, W.B.; Leslie, D.L.; Harmon, R.S.; Neumann, K.; Welch, K.A.; Bisson, K.M.; McKnight, D.M.

    2013-01-01

    Highlights: ► δ 13 C-DIC reported from McMurdo Dry Valleys, Antarctica, streams. ► Stream water δ 13 C PDB values range −9.4‰ to +5.1‰, largely inorganic in character. ► Atmospheric exchange is the dominant control on δ 13 C-DIC. - Abstract: The McMurdo Dry Valleys region of Antarctica is the largest ice-free region on the continent. This study reports the first C stable isotope measurements for dissolved inorganic C present in ephemeral streams in four dry valleys that flow for four to twelve weeks during the austral summer. One of these valleys, Taylor Valley, has been the focus of the McMurdo Dry Valleys Long-Term Ecological Research (MCM-LTER) program since 1993. Within Taylor Valley, numerous ephemeral streams deliver water to three perennially ice-covered, closed-basin lakes: Lake Fryxell, Lake Hoare, and Lake Bonney. The Onyx River in the Wright Valley, the longest river in Antarctica, flows for 40 km from the Wright Lower Glacier and Lake Brownworth at the foot of the glacier to Lake Vanda. Streamflow in the McMurdo Dry Valley streams is produced primarily from glacial melt, as there is no overland flow. However, hyporheic zone exchange can be a major hydrogeochemical process in these streams. Depending on landscape position, these streams vary in gradient, channel substrate, biomass abundance, and hyporheic zone extent. This study sampled streams from Taylor, Wright, Garwood, and Miers Valleys and conducted diurnal sampling of two streams of different character in Taylor Valley. In addition, transect sampling was undertaken of the Onyx River in Wright Valley. The δ 13 C PDB values from these streams span a range of greater than 14‰, from −9.4‰ to +5.1‰, with the majority of samples falling between −3‰ and +2‰, suggesting that the C stable isotope composition of dissolved C in McMurdo Dry Valley streams is largely inorganic in character. Because there are no vascular plants on this landscape and no groundwater input to these

  13. A modified calculation model for groundwater flowing to horizontal ...

    Indian Academy of Sciences (India)

    well pipe and aquifer couples the turbulent flow inside the horizontal seepage well with laminar flow in the aquifer. .... In the well pipe, the relationship between hydraulic head loss and flow velocity .... the steady-state mathematic model is developed for groundwater flowing to the horizontal seepage well under a river valley.

  14. Major ions composition of the groundwater and surface water ...

    African Journals Online (AJOL)

    The total ionic concentration increases dramatically from the highlands towards the rift valley following the regional groundwater flow directions to low-lying regions characterized by low annual rainfall and high evapotranspiration. In the rift the total dissolved solids (TDS) variation is dramatic (in places more than 50 fold).

  15. Geochemistry and hydrogeochemical process of groundwater in the ...

    African Journals Online (AJOL)

    Ground water is the only hydrous resource exploited in the Souf valley of Algerian Sahara. Several techniques and conventional graphical plots were used to define the geochemistry of the aquifer. Based on the ionic components, hydrochemical facies, the factors controlling groundwater chemistry are assessed and defined ...

  16. Ground water in Fountain and Jimmy Camp Valleys, El Paso County, Colorado with a section on Computations of drawdowns caused by the pumping of wells in Fountain Valley

    Science.gov (United States)

    Jenkins, Edward D.; Glover, Robert E.

    1964-01-01

    The part of Fountain Valley considered in this report extends from Colorado Springs to the Pueblo County line. It is 23 miles long and has an area of 26 square miles. The part of Jimmy Camp Valley discussed is 11 miles long and has an area of 9 square miles. The topography is characterized by level flood plains and alluvial terraces that parallel the valley and by rather steep hills along the valley sides. The climate is semiarid, average annual precipitation being about 13 inches. Farming and stock raising are the principal occupations in the valleys; however, some of the agricultural land near Colorado Springs is being used for housing developments. The Pierre Shale and alluvium underlie most of the area, and mesa gravel caps the shale hills adjacent to Fountain Valley. The alluvium yields water to domestic, stock, irrigation, and public-supply wells and is capable of yielding large quantities of water for intermittent periods. Several springs issue along the sides of the valley at the contact of the mesa gravel and the underlying Pierre Shale. The water table ranges in depth from less than 10 feet along the bottom lands to about 80 feet along the sides of the valleys; the saturated thickness ranges from less than a foot to about 50 feet. The ground-water reservoir in Fountain Valley is recharged by precipitation that falls within the area, by percolation from Fountain Creek, which originates in the Pikes Peak, Monument Valley, and Rampart Range areas, and by seepage from irrigation water. This reservoir contains about 70,000 acre-feet of ground water in storage. The ground-water reservoir in Jimmy Camp Valley is recharged from precipitation that falls within the area, by percolation from Jimmy Camp Creek during periods of streamflow, and by seepage from irrigation water. The Jimmy Camp ground-water reservoir contains about 25,000 acre-feet of water in storage. Ground water is discharged from the area by movement to the south, by evaporation and transpiration in

  17. Assessing the groundwater salinization in closed hydrologic basins due to overdraft

    Science.gov (United States)

    Guo, Z.; Pauloo, R.; Fogg, G. E.

    2016-12-01

    Population growth and the expansion of agriculture, coupled with climate uncertainties, have accelerated groundwater pumping and overdraft in alluvial aquifers worldwide. In many agricultural basins, the low rate of replenishment is far exceeded by the rate of groundwater pumping in overdrafted aquifers, which results in the substantial water table declines and in effect contributes to the formation of a "closed" basin. In fact, even modest amounts of groundwater system drawdown that do not produce what is construed as overdraft, can result in most of the groundwater discharge occurring as evapotranspiration via irrigation practices, converting the basin to a closed groundwater basin. Moreover, in past decades, extreme weather conditions (i.e., severe drought in California for the past five years) have resulted in substantially reduced surface water storage. This increases demand for groundwater to supplement low surface water supplies, and consequently, drives groundwater overdraft, and hence, groundwater salinization. In these newly closed basins, just as in other naturally closed basins such as Death Valley and the Great Salt Lake, groundwater salinity must increase not only due to evaporation, but also due to rock water interactions in the groundwater system, and lack of a natural outlet for the groundwater. In this study, the water balance and salt balance in closed basins of the Central Valley, California are computed. Groundwater degradation under the current overdraft conditions is further investigated using simple models that are developed by upscaling more complex and heterogeneous transport models. The focus of this study is to determine the applicability of these simple models to represent regional transport without explicitly including the large-scale heterogeneity inherent in the more complex models. Groundwater salinization processes, including salt accumulation caused by evapotranspiration of applied irrigation water and rock-groundwater

  18. Hydrogeology of the western part of the Salt River Valley area, Maricopa County, Arizona

    Science.gov (United States)

    Brown, James G.; Pool, D.R.

    1989-01-01

    The Salt River Valley is a major population and agricultural center of more than 3,000 mi2 in central Arizona (fig. 1). The western part of the Salt River Valley area (area of this report) covers about 1,500 mi2. The Phoenix metropolitan area with a population of more than 1.6 million in 1985 (Valley National Bank, 1987) is located within the valley. The watersheds of the Salt, Verde, and Agua Fria Rivers provide the valley with a reliable but limited surface-water supply that must be augmented with ground water even in years of plentiful rainfall. Large-scale ground-water withdrawals began in the Salt River Valley in the early part of the 20th century; between 1915 and 1983, the total estimated ground-water pumpage was 81 million acre-ft (U.S. Geological Survey, 1984). Because of the low average annual rainfall and high potential evapotranspiration, the principal sources of ground-water recharge are urban runoff, excess irrigation, canal seepage and surface-water flows during years of higher-than-normal rainfall. Withdrawals greatly exceed recharge and, in some area, ground-water levels have declines as much as 350 ft (Laney and other, 1978; Ross, 1978). In the study area, ground-water declines of more than 300 ft have occurred in Deer Valley and from Luke Air Force Base north to Beardsley. As a result, a large depression of the water table has developed west of Luke Air Force Base (fig. 2). Ground-water use has decreased in recent years because precipitation and surface-water supplies have been greater than normal. Increased precipitation also caused large quantities of runoff to be released into the normally dry Salt and Gila River channels. From February 1978 to June 1980, streamflow losses of at least 90,000 acre-ft occurred between Jointhead Dam near the east boundary of the study area and Gillespie Dam several miles southwest of the west edge of the study area (Mann and Rhone, 1983). Consequently, ground-water declines in a large part of the basin have

  19. Water availability and subsidence in California's Central Valley

    Science.gov (United States)

    Faunt, Claudia C.; Sneed, Michelle

    2015-01-01

    California’s Central Valley covers about 52,000 square kilometers (km2) and is one of the most productive agricultural regions in the world. More than 250 different crops are grown in the broad alluvial filled structural trough, with an estimated value exceeding $20 billion per year (Faunt 2009) (Figure 1). Central Valley agriculture depends on state and federal water systems that divert surface water, predominantly originating from Sierra Nevada snowmelt, to agricultural fields. Because the valley is semi-arid and the availability of surface water varies substantially from year to year, season to season, and from north to south, agriculture, as it grew, developed a reliance on groundwater for irrigation.

  20. Groundwater quality in the Mojave area, California

    Science.gov (United States)

    Dawson, Barbara J. Milby; Belitz, Kenneth

    2012-01-01

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. Four groundwater basins along the Mojave River make up one of the study areas being evaluated. The Mojave study area is approximately 1,500 square miles (3,885 square kilometers) and includes four contiguous groundwater basins: Upper, Middle, and Lower Mojave River Groundwater Basins, and the El Mirage Valley (California Department of Water Resources, 2003). The Mojave study area has an arid climate, and is part of the Mojave Desert. Average annual rainfall is about 6 inches (15 centimeters). Land use in the study area is approximately 82 percent (%) natural (mostly shrubland), 4% agricultural, and 14% urban. The primary crops are pasture and hay. The largest urban areas are the cities of Victorville, Hesperia, and Apple Valley (2010 populations of 116,000, 90,000 and 69,000, respectively). Groundwater in these basins is used for public and domestic water supply and for irrigation. The main water-bearing units are gravel, sand, silt, and clay derived from surrounding mountains. The primary aquifers in the Mojave study area are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database. Public-supply wells in the Mojave study area are completed to depths between 200 and 600 feet (18 to 61 meters), consist of solid casing from the land surface to a depth of 130 to 420 feet (40 to 128 meters), and are screened or perforated below the solid casing. Recharge to the groundwater system is primarily runoff from the mountains to the south, mostly through the Mojave River channel. The primary sources

  1. Geohydrology and possible transport routes of polychlorinated biphenyls in Haiku Valley, Oahu, Hawaii. Water resources investigation

    Energy Technology Data Exchange (ETDEWEB)

    Izuka, S.K.; Hill, B.R.; Shade, P.J.; Tribble, G.W.

    1991-01-01

    The report discusses geohydrologic evidence of ground-water and surface-water movement and sediment transport in an effort to identify routes by which water-borne contaminants may be transported within and beyond Haiku Valley. Specifically, the report describes the geologic framework of the valley and the bearing it has on the movement of ground water, and water budget of the Haiku Valley basin, the exchange between ground water and surface water, and the movement of sediment by surface water. The concentration of PCBs carried in suspended stream sediment is also described.

  2. Evaluation of the hydrologic system and selected water-management alternatives in the Owens Valley, California

    Science.gov (United States)

    Danskin, Wesley R.

    1998-01-01

    The Owens Valley, a long, narrow valley along the east side of the Sierra Nevada in eastcentral California, is the main source of water for the city of Los Angeles. The city diverts most of the surface water in the valley into the Owens River?Los Angeles Aqueduct system, which transports the water more than 200 miles south to areas of distribution and use. Additionally, ground water is pumped or flows from wells to supplement the surface-water diversions to the river? aqueduct system. Pumpage from wells needed to supplement water export has increased since 1970, when a second aqueduct was put into service, and local residents have expressed concerns that the increased pumping may have a detrimental effect on the environment and the native vegetation (indigenous alkaline scrub and meadow plant communities) in the valley. Native vegetation on the valley floor depends on soil moisture derived from precipitation and from the unconfined part of a multilayered ground-water system. This report, which describes the evaluation of the hydrologic system and selected water-management alternatives, is one in a series designed to identify the effects that ground-water pumping has on native vegetation and evaluate alternative strategies to mitigate any adverse effects caused by pumping. The hydrologic system of the Owens Valley can be conceptualized as having three parts: (1) an unsaturated zone affected by precipitation and evapotranspiration; (2) a surface-water system composed of the Owens River, the Los Angeles Aqueduct, tributary streams, canals, ditches, and ponds; and (3) a saturated ground-water system contained in the valley fill. Analysis of the hydrologic system was aided by development of a ground-water flow model of the ?aquifer system,? which is defined as the most active part of the ground-water system and which includes nearly all of the Owens Valley except for the area surrounding the Owens Lake. The model was calibrated and verified for water years 1963?88 and

  3. Groundwater ecology literature review

    OpenAIRE

    Maurice, L.

    2009-01-01

    Groundwater ecology is the study of ecosystems that occur in the subsurface within groundwater. Groundwater often contains a diverse range of organisms, and those that live in groundwater and generally do not live above the ground surface are called Stygobites. Stygobites species come from several different taxonomic groups of animals. Many animals found in groundwater are Crustaceans (Copepoda, Ostracoda, Amphipoda, Isopoda, Syncarida, Cladocera) but species of Oligocheata and...

  4. Geology, selected geophysics, and hydrogeology of the White River and parts of the Great Salt Lake Desert regional groundwater flow systems, Utah and Nevada

    Science.gov (United States)

    Rowley, Peter D.; Dixon, Gary L.; Watrus , James M.; Burns, Andrews G.; Mankinen, Edward A.; McKee, Edwin H.; Pari, Keith T.; Ekren, E. Bartlett; Patrick , William G.; Comer, John B.; Inkenbrandt, Paul C.; Krahulec, K.A.; Pinnell, Michael L.

    2016-01-01

    The east-central Great Basin near the Utah-Nevada border contains two great groundwater flow systems. The first, the White River regional groundwater flow system, consists of a string of hydraulically connected hydrographic basins in Nevada spanning about 270 miles from north to south. The northernmost basin is Long Valley and the southernmost basin is the Black Mountain area, a valley bordering the Colorado River. The general regional groundwater flow direction is north to south. The second flow system, the Great Salt Lake Desert regional groundwater flow system, consists of hydrographic basins that straddle

  5. Smart Valley Infrastructure.

    Science.gov (United States)

    Maule, R. William

    1994-01-01

    Discusses prototype information infrastructure projects in northern California's Silicon Valley. The strategies of the public and private telecommunications carriers vying for backbone services and industries developing end-user infrastructure technologies via office networks, set-top box networks, Internet multimedia, and "smart homes"…

  6. Breathing Valley Fever

    Centers for Disease Control (CDC) Podcasts

    2014-02-04

    Dr. Duc Vugia, chief of the Infectious Diseases Branch in the California Department of Public Health, discusses Valley Fever.  Created: 2/4/2014 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 2/5/2014.

  7. The buffer value of groundwater when well yield is limited

    Science.gov (United States)

    Foster, T.; Brozović, N.; Speir, C.

    2017-04-01

    A large proportion of the total value of groundwater in conjunctive use systems is associated with the ability to smooth out shortfalls in surface water supply during droughts. Previous research has argued that aquifer depletion in these regions will impact farmers negatively by reducing the available stock of groundwater to buffer production in future periods, and also by increasing the costs of groundwater extraction. However, existing studies have not considered how depletion may impact the productivity of groundwater stocks in conjunctive use systems through reductions in well yields. In this work, we develop a hydro-economic modeling framework to quantify the effects of changes in well yields on the buffer value of groundwater, and apply this model to an illustrative case study of tomato production in California's Central Valley. Our findings demonstrate that farmers with low well yields are forced to forgo significant production and profits because instantaneous groundwater supply is insufficient to buffer surface water shortfalls in drought years. Negative economic impacts of low well yields are an increasing function of surface water variability, and are also greatest for farmers operating less efficient irrigation systems. These results indicate that impacts of well yield reductions on the productivity of groundwater are an important economic impact of aquifer depletion, and that failure to consider this feedback may lead to significant errors in estimates of the value of groundwater management in conjunctive use systems.

  8. Groundwater Storage Changes: Present Status from GRACE Observations

    Science.gov (United States)

    Chen, Jianli; Famiglietti, James S.; Scanlon, Bridget R.; Rodell, Matthew

    2015-01-01

    Satellite gravity measurements from the Gravity Recovery and Climate Experiment (GRACE) provide quantitative measurement of terrestrial water storage (TWS) changes with unprecedented accuracy. Combining GRACE-observed TWS changes and independent estimates of water change in soil and snow and surface reservoirs offers a means for estimating groundwater storage change. Since its launch in March 2002, GRACE time-variable gravity data have been successfully used to quantify long-term groundwater storage changes in different regions over the world, including northwest India, the High Plains Aquifer and the Central Valley in the USA, the North China Plain, Middle East, and southern Murray-Darling Basin in Australia, where groundwater storage has been significantly depleted in recent years (or decades). It is difficult to rely on in situ groundwater measurements for accurate quantification of large, regional-scale groundwater storage changes, especially at long timescales due to inadequate spatial and temporal coverage of in situ data and uncertainties in storage coefficients. The now nearly 13 years of GRACE gravity data provide a successful and unique complementary tool for monitoring and measuring groundwater changes on a global and regional basis. Despite the successful applications of GRACE in studying global groundwater storage change, there are still some major challenges limiting the application and interpretation of GRACE data. In this paper, we present an overview of GRACE applications in groundwater studies and discuss if and how the main challenges to using GRACE data can be addressed.

  9. Uplift and seismicity driven by groundwater depletion in central California.

    Science.gov (United States)

    Amos, Colin B; Audet, Pascal; Hammond, William C; Bürgmann, Roland; Johanson, Ingrid A; Blewitt, Geoffrey

    2014-05-22

    Groundwater use in California's San Joaquin Valley exceeds replenishment of the aquifer, leading to substantial diminution of this resource and rapid subsidence of the valley floor. The volume of groundwater lost over the past century and a half also represents a substantial reduction in mass and a large-scale unburdening of the lithosphere, with significant but unexplored potential impacts on crustal deformation and seismicity. Here we use vertical global positioning system measurements to show that a broad zone of rock uplift of up to 1-3 mm per year surrounds the southern San Joaquin Valley. The observed uplift matches well with predicted flexure from a simple elastic model of current rates of water-storage loss, most of which is caused by groundwater depletion. The height of the adjacent central Coast Ranges and the Sierra Nevada is strongly seasonal and peaks during the dry late summer and autumn, out of phase with uplift of the valley floor during wetter months. Our results suggest that long-term and late-summer flexural uplift of the Coast Ranges reduce the effective normal stress resolved on the San Andreas Fault. This process brings the fault closer to failure, thereby providing a viable mechanism for observed seasonality in microseismicity at Parkfield and potentially affecting long-term seismicity rates for fault systems adjacent to the valley. We also infer that the observed contemporary uplift of the southern Sierra Nevada previously attributed to tectonic or mantle-derived forces is partly a consequence of human-caused groundwater depletion.

  10. Hydrogeological reconnaissance study: Dyfi Valley, Wales

    International Nuclear Information System (INIS)

    Glendining, S.J.

    1981-10-01

    This report describes work carried out for the Department of the Environment as part of its research programme into radioactive waste management. It presents an account of a hydrogeological reconnaissance study in the Dyfi Valley area of Central Wales. Initially the purposes of such a study are given and the assumptions used in deriving parameters such as flow volume, path length and transit time in areas of massive fractured rocks are described. Using these assumptions with geological, topographic and hydrometeorological data the potential ranges in properties such as bulk hydraulic conductivity, path lengths, hydraulic gradients and volumes of groundwater flow have been determined. These ranges have been used to estimate solute transport model parameters. The limitations and usefulness of the reconnaissance study in planning research and siting exploratory boreholes in the Dyfi area are discussed. (author)

  11. Determination of groundwater flow velocity by radon measurements

    International Nuclear Information System (INIS)

    Hohn, E.; von Gunten, H.R.

    1990-01-01

    The groundwater resources of glacio-fluvial perialpine valleys are recharged significantly by the infiltration from rivers. The groundwater residence times between rivers and wells should be known in groundwater management problems. Short residence times can be estimated using radon. Radon concentrations in rivers are usually very low. Upon filtration and movement of the water in the ground, radon is picked up and its concentration increases by 2-3 orders of magnitude according to radioactive growth laws. Residence times and flow velocities can be estimated from the increasing radon concentrations measured in groundwater sampling tubes at different distances from the river. Results obtained with this method agree with the results from experiments with artificial tracers

  12. Salinity of deep groundwater in California: Water quantity, quality, and protection.

    Science.gov (United States)

    Kang, Mary; Jackson, Robert B

    2016-07-12

    Deep groundwater aquifers are poorly characterized but could yield important sources of water in California and elsewhere. Deep aquifers have been developed for oil and gas extraction, and this activity has created both valuable data and risks to groundwater quality. Assessing groundwater quantity and quality requires baseline data and a monitoring framework for evaluating impacts. We analyze 938 chemical, geological, and depth data points from 360 oil/gas fields across eight counties in California and depth data from 34,392 oil and gas wells. By expanding previous groundwater volume estimates from depths of 305 m to 3,000 m in California's Central Valley, an important agricultural region with growing groundwater demands, fresh [groundwater volume is almost tripled to 2,700 km(3), most of it found shallower than 1,000 m. The 3,000-m depth zone also provides 3,900 km(3) of fresh and saline water, not previously estimated, that can be categorized as underground sources of drinking water (USDWs; groundwater, especially USDWs. Our findings indicate that California's Central Valley alone has close to three times the volume of fresh groundwater and four times the volume of USDWs than previous estimates suggest. Therefore, efforts to monitor and protect deeper, saline groundwater resources are needed in California and beyond.

  13. Groundwater recharge: Accurately representing evapotranspiration

    CSIR Research Space (South Africa)

    Bugan, Richard DH

    2011-09-01

    Full Text Available Groundwater recharge is the basis for accurate estimation of groundwater resources, for determining the modes of water allocation and groundwater resource susceptibility to climate change. Accurate estimations of groundwater recharge with models...

  14. A 10-year plan to study the aquifer system of Indian Wells Valley, California

    Science.gov (United States)

    Lipinski, Paul; Knochenmus, Darwin D.

    1981-01-01

    Water needs of the population of Indian Wells Valley, Calif., must be met through further development of ground-water resources. Studies show that annual ground-water pumpage there has increased since 1945 and has exceeded mean annual recharge since 1966. Continued and increased stress on the aquifer system of the valley is expected because population in the valley is predicted to double by 1998 and triple by 2020, based on 1977 population figures. The U.S. Geological Survey proposes a 10-year program to develop a data base to aid in evaluation of future water-management alternatives. A study plan has been developed that describes present and potential problems and objectives of the program, and outlines work items to be undertaken in the study area. (USGS)

  15. Preliminary results of hydrogeologic investigations Humboldt River Valley, Winnemucca, Nevada

    Science.gov (United States)

    Cohen, Philip M.

    1964-01-01

    Most of the ground water of economic importance and nearly all the ground water closely associated with the flow o# the Humboldt River in the. 40-mile reach near Winnemucca, Nev., are in unconsolidated sedimentary deposits. These deposits range in age from Pliocene to Recent and range in character from coarse poorly sorted fanglomerate to lacustrine strata of clay, silt, sand, and gravel. The most permeable deposit consists of sand and gravel of Lake Lahontan age--the so-called medial gravel unit--which is underlain and overlain by fairly impermeable silt and clay also of Lake Lahontan age. The ultimate source of nearly all the water in the study area is precpitation within the drainage basin of the Humboldt River. Much of this water reaches the study, area as flow or underflow of the Humboldt River and as underflow from other valleys tributary to the study area. Little if any flow from the tributary streams in the study area usually reaches the Humboldt River. Most of the tributary streamflow within the study area evaporates or is transpired by vegetation, but a part percolates downward through unconsolidated deposits of the alluvial fans flanking the mountains and move downgradient as ground-water underflow toward the Humboldt River. Areas that contribute significant amounts of ground-water underflow to. the valley of the Humboldt River within the study area are (1) the valley of the Humboldt River upstream from the study area, (2) the Pole Creek-Rock Creek area, (3) Paradise Valley, and (4) Grass Valley and the northwestern slope of the Sonoma Range. The total average underflow from these areas in the period 1949-61 was about 14,000-19,000 acre-feet per year. Much of this underflow discharged into the Humboldt River within the study area and constituted a large part of the base flow of the river. Streamflow in the Humboldt River increases substantially in the early spring, principally because of runoff to the river in the reaches upstream from the study area

  16. Coupling surface water (Delft3D) to groundwater (MODFLOW) in the Bay-Delta community model: the effect of major abstractions in the Delta

    Science.gov (United States)

    Hendriks, D.; Ball, S. M.; Van der Wegen, M.; Verkaik, J.; van Dam, A.

    2016-12-01

    We present a coupled groundwater-surface water model for the San Francisco Bay and Sacramento Valley that consists of a combination of a spatially-distributed groundwater model (Modflow) based on the USGS Central Valley model(1) and the Flexible Mesh (FM) surface water model of the Bay Area(2). With this coupled groundwater-surface water model, we assessed effects of climate, surface water abstractions and groundwater pumping on surface water and groundwater levels, groundwater-surface water interaction and infiltration/seepage fluxes. Results show that the effect of climate (high flow and low flow) on surface water and groundwater is significant and most prominent in upstream areas. The surface water abstractions cause significant local surface water levels decrease (over 2 m), which may cause inflow of bay water during low flow periods, resulting in salinization of surface water in more upstream areas. Groundwater level drawdown due to surface water withdrawal is moderate and limited to the area of the withdrawals. The groundwater pumping causes large groundwater level drawdowns (up to 0.8 m) and significant changes in seepage/infiltration fluxes in the model. However, the effect on groundwater-surface water exchange is relatively small. The presented model instrument gives a sound first impression of the effects of climate and water abstraction on both surface water and groundwater. The combination of Modflow and Flexible Mesh has potential for modelling of groundwater-surface water exchange in deltaic areas, also in other parts of the world. However, various improvements need to be made in order to make the simulation results useful in practice. In addition, a water quality aspect could be added to assess salinization processes as well as groundwater-surface water aspects of water and soil pollution. (1) http://ca.water.usgs.gov/projects/central-valley/central-valley-hydrologic-model.html (2) www.d3d-baydelta.org

  17. Groundwater Managment Districts

    Data.gov (United States)

    Kansas Data Access and Support Center — This dataset outlines the location of the five Groundwater Management Districts in Kansas. GMDs are locally formed and elected boards for regional groundwater...

  18. Groundwater availability of the Mississippi embayment

    Science.gov (United States)

    Clark, Brian R.; Hart, Rheannon M.; Gurdak, Jason J.

    2011-01-01

    Groundwater is an important resource for agricultural and municipal uses in the Mississippi embayment. Arkansas ranks first in the Nation for rice and third for cotton production, with both crops dependent on groundwater as a major source of irrigation requirements. Multiple municipalities rely on the groundwater resources to provide water for industrial and public use, which includes the city of Memphis, Tennessee. The demand for the groundwater resource has resulted in groundwater availability issues in the Mississippi embayment including: (1) declining groundwater levels of 50 feet or more in the Mississippi River Valley alluvial aquifer in parts of eastern Arkansas from agricultural pumping, (2) declining groundwater levels of over 360 feet over the last 90 years in the confined middle Claiborne aquifer in southern Arkansas and northern Louisiana from municipal pumping, and (3) litigation between the State of Mississippi and a Memphis water utility over water rights in the middle Claiborne aquifer. To provide information to stakeholders addressing the groundwater-availability issues, the U.S. Geological Survey Groundwater Resources Program supported a detailed assessment of groundwater availability through the Mississippi Embayment Regional Aquifer Study (MERAS). This assessment included (1) an evaluation of how these resources have changed over time through the use of groundwater budgets, (2) development of a numerical modeling tool to assess system responses to stresses from future human uses and climate trends, and (3) application of statistical tools to evaluate the importance of individual observations within a groundwater-monitoring network. An estimated 12 million acre-feet per year (11 billion gallons per day) of groundwater was pumped in 2005 from aquifers in the Mississippi embayment. Irrigation constitutes the largest groundwater use, accounting for approximately 10 million acre-feet per year (9 billion gallons per day) in 2000 from the Mississippi

  19. Seasonal groundwater turnover

    OpenAIRE

    Nordell, Bo; Engström, Maria

    2006-01-01

      Seasonal air temperature variations and corresponding changes in groundwater temperature cause convective movements in groundwater similar to the seasonal turnover in lakes. Numerical simulations were performed to investigate the natural conditions for thermally driven groundwater convection to take place. Thermally driven convection could be triggered by a horizontal groundwater flow, Convection then starts at a considerably lower Rayleigh number (Ra) than the general critical Rayleigh ...

  20. Rift Valley fever vaccines

    OpenAIRE

    Ikegami, Tetsuro; Makino, Shinji

    2009-01-01

    Rift Valley fever virus (RVFV), which belongs to the genus Phlebovirus, family Bunyaviridae, is a negative-stranded RNA virus carrying a tripartite RNA genome. RVFV is transmitted by mosquitoes and causes large outbreaks among ruminants and humans in Africa and the Arabian Peninsula. Human patients develop an acute febrile illness, followed by a fatal hemorrhagic fever, encephalitis or ocular diseases, whereas ruminants experience abortions during outbreak. Effective vaccination of both human...

  1. Assessing dissolved methane patterns in central New York groundwater

    Directory of Open Access Journals (Sweden)

    Lauren E. McPhillips

    2014-07-01

    New hydrological insights for this region: There was no significant difference between methane concentrations in valleys versus upslope locations, in water wells less than or greater than 1 km from a conventional gas well, and across different geohydrologic units. Methane concentrations were significantly higher in groundwater dominated by sodium chloride or sodium bicarbonate compared with groundwater dominated by calcium bicarbonate, indicating bedrock interactions and lengthy residence times as controls. A multivariate regression model of dissolved methane using only three variables (sodium, hardness, and barium explained 77% of methane variability, further emphasizing the dominance of geochemistry and hydrogeology as controls on baseline methane patterns.

  2. Calendar year 1994 groundwater quality report for the Bear Creek hydrogeologic regime, Y-12 Plant, Oak Ridge, Tennessee. 1994 Groundwater quality data interpretations and proposed program modifications

    International Nuclear Information System (INIS)

    1995-10-01

    This groundwater quality report (GWQR) contains an evaluation of the groundwater quality data obtained during the 1994 calendar year (CY) at several hazardous and non-hazardous waste management facilities at the US Department of Energy (DOE) Y-12 Plant. These sites lie in Bear Creek Valley (BCV) west of the Y-12 Plant within the boundaries of the Bear Creek Hydrogeologic Regime which is one of three hydrogeologic regimes defined for the purposes of groundwater quality monitoring. The Environmental Management Department manages the groundwater monitoring activities under the auspices of the Y-12 Plant Groundwater Protection Program (GWPP). The purpose of the GWPP is to characterize the hydrogeology and to monitor groundwater quality at the Y-12 Plant and surrounding area to protect local groundwater resources. The annual GWQR for the Bear Creek Regime is completed in two parts. Part 1 consists primarily of data appendices and serves as a reference for the groundwater quality data obtained each CY. Part 2 (this report) contains an evaluation of the data with respect to regime-wide groundwater quality, summarizes the status and findings of ongoing hydrogeologic studies, describes changes in monitoring priorities, and presents planned modifications to the groundwater sampling and analysis activities

  3. Development of A Mississippi River Alluvial Aquifer Groundwater Model

    Science.gov (United States)

    Karakullukcu, R. E.; Tsai, F. T. C.; Bhatta, D.; Paudel, K.; Kao, S. C.

    2017-12-01

    The Mississippi River Alluvial Aquifer (MRAA) underlies the Mississippi River Valley of the northeastern Louisiana, extending from the north border of Louisiana and Arkansas to south central of Louisiana. The MRAA has direct contact with the Mississippi River. However, the interaction between the Mississippi River and the alluvial aquifer is largely unknown. The MRAA is the second most used groundwater source in Louisiana's aquifers with about 390 million gallons per day, which is about 25% of all groundwater withdrawals in Louisiana. MRAA is the major water source to agriculture in the northeastern Louisiana. The groundwater withdrawals from the MRAA increases annually for irrigation. High groundwater pumping has caused significant groundwater level decline and elevated salinity in the aquifer. Therefore, dealing with agricultural irrigation is the primary purpose for managing the MRAA. The main objective of this study is to develop a groundwater model as a tool for the MRAA groundwater management. To do so, a hydrostratigraphy model of the MRAA was constructed by using nearly 8,000 drillers' logs and electric logs collected from Louisiana Department of Natural Resources. The hydrostratigraphy model clearly shows that the Mississippi River cuts into the alluvial aquifer. A grid generation technique was developed to convert the hydrostratigraphy model into a MODFLOW model with 12 layers. A GIS-based method was used to estimate groundwater withdrawals for irrigation wells based on the crop location and acreage from the USDACropScape - Cropland Data Layer. Results from the Variable Infiltration Capacity (VIC) model were used to determine potential recharge. NHDPlusV2 data was used to determine water level for major streams for the MODFLOW River Package. The groundwater model was calibrated using groundwater data between 2004 and 2015 to estimate aquifer hydraulic conductivity, specific yield, specific storage, river conductance, and surficial recharge.

  4. Principal facts for new gravity stations in the Pahute Mesa and Oasis Valley areas, Nye County, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, Jeffrey G.; Hildenbrand, Thoma G.; Mankinen, Edward A.; Roberts, Carter W.

    1998-12-15

    Regional gravity and aeromagnetic maps of the Pahute Mesa and Oasis Valley region indicate the presence of several structures that may influence the flow of groundwater. For example, several prominent linear features expressed by both gravity and aeromagentic data could act either as barriers or conduits for groundwater. The current gravity study was undertaken to better define the boundaries of the interpreted major regional structures in the area.

  5. The California Valley grassland

    Science.gov (United States)

    Keeley, J.E.; Schoenherr, Allan A.

    1990-01-01

    Grasslands are distributed throughout California from Oregon to Baja California Norte and from the coast to the desert (Brown 1982) (Figure 1). This review will focus on the dominant formation in cismontane California, a community referred to as Valley Grassland (Munz 1959). Today, Valley Grassland is dominated by non-native annual grasses in genera such as Avena (wild oat), Bromus (brome grass), and Hordeum (barley), and is often referred to as the California annual grassland. On localized sites, native perennial bunchgrasses such as Stipa pultra (purple needle grass) may dominate and such sites are interpreted to be remnants of the pristine valley grassland. In northwestern California a floristically distinct formation of the Valley Grassland, known as Coast Prairie (Munz 1959) or Northern Coastal Grassland (Holland and Keil 1989) is recognized. The dominant grasses include many native perennial bunchgrasses in genera such as Agrostis, Calamagrostis, Danthonia, Deschampsia, Festuca, Koeleria and Poa (Heady et al. 1977). Non-native annuals do not dominate, but on some sites non-native perennials like Anthoxanthum odoratum may colonize the native grassland (Foin and Hektner 1986). Elevationally, California's grasslands extend from sea level to at leas 1500 m. The upper boundary is vague because montane grassland formations are commonly referred to as meadows; a community which Munz (1959) does not recognize. Holland and Keil (1989) describe the montane meadow as an azonal community; that is, a community restricted not so much to a particular climatic zone but rather controlled by substrate characteristics. They consider poor soil-drainage an over-riding factor in the development of montane meadows and, in contrast to grasslands, meadows often remain green through the summer drought. Floristically, meadows are composed of graminoids; Cyperaceae, Juncaceae, and rhizomatous grasses such as Agropyron (wheat grass). Some bunchgrasses, such as Muhlenbergia rigens, are

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-03-21

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

  7. Groundwater model of the Great Basin carbonate and alluvial aquifer system version 3.0: Incorporating revisions in southwestern Utah and east central Nevada

    Science.gov (United States)

    Brooks, Lynette E.

    2017-12-01

    The groundwater model described in this report is a new version of previously published steady-state numerical groundwater flow models of the Great Basin carbonate and alluvial aquifer system, and was developed in conjunction with U.S. Geological Survey studies in Parowan, Pine, and Wah Wah Valleys, Utah. This version of the model is GBCAAS v. 3.0 and supersedes previous versions. The objectives of the model for Parowan Valley were to simulate revised conceptual estimates of recharge and discharge, to estimate simulated aquifer storage properties and the amount of reduction in storage as a result of historical groundwater withdrawals, and to assess reduction in groundwater withdrawals necessary to mitigate groundwater-level declines in the basin. The objectives of the model for the area near Pine and Wah Wah Valleys were to recalibrate the model using new observations of groundwater levels and evapotranspiration of groundwater; to provide new estimates of simulated recharge, hydraulic conductivity, and interbasin flow; and to simulate the effects of proposed groundwater withdrawals on the regional flow system. Meeting these objectives required the addition of 15 transient calibration stress periods and 14 projection stress periods, aquifer storage properties, historical withdrawals in Parowan Valley, and observations of water-level changes in Parowan Valley. Recharge in Parowan Valley and withdrawal from wells in Parowan Valley and two nearby wells in Cedar City Valley vary for each calibration stress period representing conditions from March 1940 to November 2013. Stresses, including recharge, are the same in each stress period as in the steady-state stress period for all areas outside of Parowan Valley. The model was calibrated to transient conditions only in Parowan Valley. Simulated storage properties outside of Parowan Valley were set the same as the Parowan Valley properties and are not considered calibrated. Model observations in GBCAAS v. 3.0 are

  8. Wright Valley Sediments as Potential Analogs for Martian Surface Processes

    Science.gov (United States)

    Englert, P. A. J.; Bishop, J. L.; Patel, S.; Gibson, E. K.; Koeberl, C.

    2015-12-01

    The Antarctic Dry Valleys (ADV) may provide a unique terrestrial analog for current Martian surface processes. The Wright Valley located in the ADV contains streams, lakes and ponds that host highly saline, sedimentary environments. This project highlights comparisons of formation and salt accumulation processes at the Don Juan Pond (DJP) and Don Quixote Pond (DQP). These are located in the north and south forks of the Wright Valley, which are unique areas where unusual terrestrial processes can be studied. DQP is located in the western part of the north fork about 100 m above mean seawater level. The DQP Valley walls are up to 2500 m high and the brine is seasonally frozen. DJP from the south fork is located ~9 km west of Lake Vanda. The basin floor is 117 m above mean seawater level with activity to the north and south rising above 1000 m. The DJP brine does not freeze and may be a model environment for Ca and Cl weathering and distribution on Mars. Our findings indicate that DJP and DQP have formed in similar climatic and geological environments, but likely experienced different formation conditions. Samples were collected from surface, soil pits and depth profiles during the 1979/1980, the 1990/1991 and the 2005/2006 field seasons. Elemental abundances and mineralogy were evaluated for several sets of sediments. The DJP basin shows low surface abundances of halite and relatively high abundances of sulfates throughout with gypsum or anhydrite dominating at different locations. The DQP area has high surface abundances of halite with gypsum present as the major sulfate. Two models have been proposed to explain these differences: DQP may have formed through a combination of shallow and some deep groundwater influx, while deep groundwater upwelling likely played the dominant role of salt formation at DJP. Our study seeks to understand the formation of DQP and DJP as unique terrestrial processes and as models for Ca, Cl, and S weathering and distribution on Mars.

  9. Discussion on the origin of surface failures in the Valley of Aguascalientes, México

    Directory of Open Access Journals (Sweden)

    M. Hernández-Marín

    2015-11-01

    Full Text Available Surface failures have been observed in the valley of Aguascalientes since the early 1980's. Although, groundwater pumping began in the early 1950's but became intensive until the late 1970's, when many of the surface failures appeared. For this reason, surface deformation (surface failures and land subsidence has been associated to groundwater withdrawal. Recent observations, however, suggest that some of these surface discontinuities are the result of natural geologic stresses rather than those associated groundwater decline, at least in its origin. Geologically, this valley is a tectonic graben flanked by two north-to-south trending normal faults, and seismicity of low intensity has been detected into the valley evidencing that the study area is seismically active. In this work, we present and discuss evidence showing tectonic discontinuities on the surface or at a shallow depth. Evidence presented in this investigation brings up uncertainty about the purely pumping-induced origin of fissuring in the valley, and allows addressing some key questions, for instance, are the surface failures caused by the combined stresses of pumping and tectonism? Is the current tectonism sufficient to cause some surface or deep failures?

  10. Subsidence and Rebound in California's Central Valley: Effects of Pumping, Geology, and Precipitation

    Science.gov (United States)

    Farr, T. G.; Fairbanks, A.

    2017-12-01

    Recent rains in California caused a pause, and even a reversal in some areas, of the subsidence that has plagued the Central Valley for decades. The 3 main drivers of surface deformation in the Central Valley are: Subsurface hydro-geology, precipitation and surface water deliveries, and groundwater pumping. While the geology is relatively fixed in time, water inputs and outputs vary greatly both in time and space. And while subsurface geology and water inputs are reasonably well-known, information about groundwater pumping amounts and rates is virtually non-existent in California. We have derived regional maps of surface deformation in the region for the period 2006 - present which allow reconstruction of seasonal and long-term changes. In order to understand the spatial and temporal patterns of subsidence and rebound in the Central Valley, we have been compiling information on the geology and water inputs and have attempted to infer pumping rates using maps of fallowed fields and published pumping information derived from hydrological models. In addition, the spatial and temporal patterns of hydraulic head as measured in wells across the region allow us to infer the spatial and temporal patterns of groundwater pumping and recharge more directly. A better understanding of how different areas (overlying different stratigraphy) of the Central Valley respond to water inputs and outputs will allow a predictive capability, potentially defining sustainable pumping rates related to water inputs. * work performed under contract to NASA and the CA Dept. of Water Resources

  11. Audiomagnetotelluric investigation of Snake Valley, eastern Nevada and western Utah

    Science.gov (United States)

    McPhee, Darcy K.; Pari, Keith; Baird, Frank

    2009-01-01

    Audiomagnetotelluric (AMT) data along four profiles in western Snake Valley and the corresponding two-dimensional (2-D) inverse models reveal subsurface structures that may be significant to ground-water investigations in the area. The AMT method is a valuable tool for estimating the electrical resistivity of the earth over depth ranges from a few meters to less than one kilometer. The method has the potential to identify faults and stratigraphy within basins of eastern Nevada, thereby helping define the hydrogeologic framework of the region.

  12. Analysis of groundwater flow beneath ice sheets

    International Nuclear Information System (INIS)

    Boulton, G. S.; Zatsepin, S.; Maillot, B.

    2001-03-01

    The large-scale pattern of subglacial groundwater flow beneath European ice sheets was analysed in a previous report. It was based on a two-dimensional flowline model. In this report, the analysis is extended to three dimensions by exploring the interactions between groundwater and tunnel flow. A theory is developed which suggests that the large-scale geometry of the hydraulic system beneath an ice sheet is a coupled, self-organising system. In this system the pressure distribution along tunnels is a function of discharge derived from basal meltwater delivered to tunnels by groundwater flow, and the pressure along tunnels itself sets the base pressure which determines the geometry of catchments and flow towards the tunnel. The large-scale geometry of tunnel distribution is a product of the pattern of basal meltwater production and the transmissive properties of the bed. The tunnel discharge from the ice margin of the glacier, its seasonal fluctuation and the sedimentary characteristics of eskers are largely determined by the discharge of surface meltwater which penetrates to the bed in the terminal zone. The theory explains many of the characteristics of esker systems and can account for tunnel valleys. It is concluded that the large-scale hydraulic regime beneath ice sheets is largely a consequence of groundwater/tunnel flow interactions and that it is essential similar to non-glacial hydraulic regimes. Experimental data from an Icelandic glacier, which demonstrates measured relationships between subglacial tunnel flow and groundwater flow during the transition from summer to winter seasons for a modern glacier, and which support the general conclusions of the theory is summarised in an appendix

  13. Groundwater sustainability strategies

    Science.gov (United States)

    Gleeson, Tom; VanderSteen, Jonathan; Sophocleous, Marios A.; Taniguchi, Makoto; Alley, William M.; Allen, Diana M.; Zhou, Yangxiao

    2010-01-01

    Groundwater extraction has facilitated significant social development and economic growth, enhanced food security and alleviated drought in many farming regions. But groundwater development has also depressed water tables, degraded ecosystems and led to the deterioration of groundwater quality, as well as to conflict among water users. The effects are not evenly spread. In some areas of India, for example, groundwater depletion has preferentially affected the poor. Importantly, groundwater in some aquifers is renewed slowly, over decades to millennia, and coupled climate–aquifer models predict that the flux and/or timing of recharge to many aquifers will change under future climate scenarios. Here we argue that communities need to set multigenerational goals if groundwater is to be managed sustainably.

  14. Hydrochemical and isotopic characteristics of groundwater in the northeastern Tennger Desert, northern China

    Science.gov (United States)

    Wang, Liheng; Dong, Yanhui; Xu, Zhifang; Qiao, Xiaojuan

    2017-12-01

    Groundwater is typically the only water source in arid regions, and its circulation processes should be better understood for rational resource exploitation. Stable isotopes and major ions were investigated in the northeastern Tengger Desert, northern China, to gain insights into groundwater recharge and evolution. In the northern mountains, Quaternary unconsolidated sediments, exposed only in valleys between hills, form the main aquifer, which is mainly made of aeolian sand and gravel. Most of the mountain groundwater samples plot along the local meteoric water line (LMWL), with a more depleted signature compared to summer precipitation, suggesting that mountain groundwater was recharged by local precipitation during winter. Most of the groundwater was fresh, with total dissolved solids less than 1 g/L; dominant ions are Na+, SO4 2- and Cl-, and all mineral saturation indices are less than zero. Evaporation, dissolution and cation exchange are the major hydrogeochemical processes. In the southern plains, however, the main aquifers are sandstone. The linear regression line of δD and δ 18O of groundwater parallels the LMWL but the intercept is lower, indicating that groundwater in the plains has been recharged by ancient precipitation rather than modern. Both calcite and dolomite phases in the plains groundwater are close to saturation, while gypsum and halite can still be dissolved into the groundwater. Different recharge mechanisms occur in the northern mountains and the southern plains, and the hydraulic connection between them is weak. Because of the limited recharge, groundwater exploitation should be limited as much as possible.

  15. Groundwater quality in the San Diego Drainages Hydrogeologic Province, California

    Science.gov (United States)

    Wright, Michael T.; Belitz, Kenneth

    2011-01-01

    More than 40 percent of California's drinking water is from groundwater. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State's groundwater quality and increases public access to groundwater-quality information. The San Diego Drainages Hydrogeologic Province (hereinafter referred to as San Diego) is one of the study units being evaluated. The San Diego study unit is approximately 3,900 square miles and consists of the Temecula Valley, Warner Valley, and 12 other alluvial basins (California Department of Water Resources, 2003). The study unit also consists of all areas outside defined groundwater basins that are within 3 kilometers of a public-supply well. The study unit was separated, based primarily on hydrogeologic settings, into four study areas: Temecula Valley, Warner Valley, Alluvial Basins, and Hard Rock (Wright and others, 2005). The sampling density for the Hard Rock study area, which consists of areas outside of groundwater basins, was much lower than for the other study areas. Consequently, aquifer proportions for the Hard Rock study area are not used to calculate the aquifer proportions shown by the pie charts. An assessment of groundwater quality for the Hard Rock study area can be found in Wright and Belitz, 2011. The temperatures in the coastal part of the study unit are mild with dry summers, moist winters, and an average annual rainfall of about 10 inches. The temperatures in the mountainous eastern part of the study unit are cooler than in the coastal part, with an annual precipitation of about 45 inches that occurs mostly in the winter. The primary aquifers consist of Quaternary-age alluvium and weathered bedrock in the Temecula Valley, Warner Valley, and Alluvial Basins study areas, whereas in the Hard Rock study area the primary aquifers consist mainly of fractured and

  16. Stratigraphic variations and secondary porosity within the Maynardville Limestone in Bear Creek Valley, Y-12 Plant, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    Goldstrand, P.M.

    1995-05-01

    To evaluate groundwater and surface water contamination and migration near the Oak Ridge Y-12 plant, a Comprehensive Groundwater Monitoring Plan was developed. As part of the Maynardville exit pathways monitoring program, monitoring well clusters were ii installed perpendicular to the strike of the Maynardville Limestone, that underlies the southern part of the Y-12 Plant and Bear Creek Valley (BCV). The Maynardville Project is designed to locate potential exit pathways of groundwater, study geochemical characteristics and factors affecting the occurrence and distribution of water-bearing intervals, and provide hydrogeologic information to be used to reduce the potential impacts of contaminants entering the Maynardville Limestone

  17. Stratigraphic variations and secondary porosity within the Maynardville Limestone in Bear Creek Valley, Y-12 Plant, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    Goldstrand, P.M. [Univ. of Nevada, Reno, NV (United States)

    1995-05-01

    To evaluate groundwater and surface water contamination and migration near the Oak Ridge Y-12 plant, a Comprehensive Groundwater Monitoring Plan was developed. As part of the Maynardville exit pathways monitoring program, monitoring well clusters were ii installed perpendicular to the strike of the Maynardville Limestone, that underlies the southern part of the Y-12 Plant and Bear Creek Valley (BCV). The Maynardville Project is designed to locate potential exit pathways of groundwater, study geochemical characteristics and factors affecting the occurrence and distribution of water-bearing intervals, and provide hydrogeologic information to be used to reduce the potential impacts of contaminants entering the Maynardville Limestone.

  18. Response of groundwater level and surface-water/groundwater interaction to climate variability: Clarence-Moreton Basin, Australia

    Science.gov (United States)

    Cui, Tao; Raiber, Matthias; Pagendam, Dan; Gilfedder, Mat; Rassam, David

    2017-08-01

    Understanding the response of groundwater levels in alluvial and sedimentary basin aquifers to climatic variability and human water-resource developments is a key step in many hydrogeological investigations. This study presents an analysis of groundwater response to climate variability from 2000 to 2012 in the Queensland part of the sedimentary Clarence-Moreton Basin, Australia. It contributes to the baseline hydrogeological understanding by identifying the primary groundwater flow pattern, water-level response to climate extremes, and the resulting dynamics of surface-water/groundwater interaction. Groundwater-level measurements from thousands of bores over several decades were analysed using Kriging and nonparametric trend analysis, together with a newly developed three-dimensional geological model. Groundwater-level contours suggest that groundwater flow in the shallow aquifers shows local variations in the close vicinity of streams, notwithstanding general conformance with topographic relief. The trend analysis reveals that climate variability can be quickly reflected in the shallow aquifers of the Clarence-Moreton Basin although the alluvial aquifers have a quicker rainfall response than the sedimentary bedrock formations. The Lockyer Valley alluvium represents the most sensitively responding alluvium in the area, with the highest declining (-0.7 m/year) and ascending (2.1 m/year) Sen's slope rates during and after the drought period, respectively. Different surface-water/groundwater interaction characteristics were observed in different catchments by studying groundwater-level fluctuations along hydrogeologic cross-sections. The findings of this study lay a foundation for future water-resource management in the study area.

  19. Response of groundwater level and surface-water/groundwater interaction to climate variability: Clarence-Moreton Basin, Australia

    Science.gov (United States)

    Cui, Tao; Raiber, Matthias; Pagendam, Dan; Gilfedder, Mat; Rassam, David

    2018-03-01

    Understanding the response of groundwater levels in alluvial and sedimentary basin aquifers to climatic variability and human water-resource developments is a key step in many hydrogeological investigations. This study presents an analysis of groundwater response to climate variability from 2000 to 2012 in the Queensland part of the sedimentary Clarence-Moreton Basin, Australia. It contributes to the baseline hydrogeological understanding by identifying the primary groundwater flow pattern, water-level response to climate extremes, and the resulting dynamics of surface-water/groundwater interaction. Groundwater-level measurements from thousands of bores over several decades were analysed using Kriging and nonparametric trend analysis, together with a newly developed three-dimensional geological model. Groundwater-level contours suggest that groundwater flow in the shallow aquifers shows local variations in the close vicinity of streams, notwithstanding general conformance with topographic relief. The trend analysis reveals that climate variability can be quickly reflected in the shallow aquifers of the Clarence-Moreton Basin although the alluvial aquifers have a quicker rainfall response than the sedimentary bedrock formations. The Lockyer Valley alluvium represents the most sensitively responding alluvium in the area, with the highest declining (-0.7 m/year) and ascending (2.1 m/year) Sen's slope rates during and after the drought period, respectively. Different surface-water/groundwater interaction characteristics were observed in different catchments by studying groundwater-level fluctuations along hydrogeologic cross-sections. The findings of this study lay a foundation for future water-resource management in the study area.

  20. The distribution and modeling of nitrate transport in the Carson Valley alluvial aquifer, Douglas County, Nevada

    Science.gov (United States)

    Naranjo, Ramon C.; Welborn, Toby L.; Rosen, Michael R.

    2013-01-01

    Residents of Carson Valley in Douglas County, Nevada, rely on groundwater from an alluvial aquifer for domestic use and agricultural irrigation. Since the 1970s, there has been a rapid increase in population in several parts of the valley that rely on domestic wells for drinking water and septic systems for treatment of household waste. As a result, the density of septic systems in the developed areas is greater than one septic system per 3 acres, and the majority of the domestic wells are shallow (screened within 250 feet of the land surface).

  1. Erosional valleys in the Thaumasia region of Mars: Hydrothermal and seismic origins

    Science.gov (United States)

    Tanaka, Kenneth L.; Dohm, James M.; Lias, Juan H.; Hare, Trent M.

    1998-12-01

    Analysis of erosional valleys, geologic materials and features, and topography through time in the Thaumasia region of Mars using co-registered digital spatial data sets reveals significant associations that relate to valley origin. Valleys tend to originate (1) on Noachian to Early Hesperian (stages 1 and 2) large volcanoes, (2) within 50-100 km of stages 1 and 2 rift systems, and (3) within 100 km of Noachian (stage 1) impact craters >50 km in diameter. These geologic preferences explain observations of higher valley-source densities (VSDs) in areas of higher elevations and regional slopes (>1°) because the volcanoes, rifts, and craters form high, steep topography or occur in terrain of high relief. Other stage 1 and stage 2 high, steep terrains, however, do not show high VSDs. The tendency for valleys to concentrate near geologic features and the overall low drainage densities in Thaumasia compared to terrestrial surfaces rule out widespread precipitation as a major factor in valley formation (as is proposed in warm, wet climate scenarios) except perhaps during the Early Noachian, for which much of the geologic record has been obliterated. Instead, volcanoes and rifts may indicate the presence of shallow crustal intrusions that could lead to local hydrothermal circulation, melting of ground ice and snow, and groundwater sapping. However, impact-crater melt would provide a heat source at the surface that might drive away water, forming valleys in the process. Post-stage 1 craters mostly have low nearby VSDs, which, for valleys incised in older rocks, suggests burial by ejecta and, for younger valleys, may indicate desiccation of near-surface water and deepening of the cryosphere. Later Hesperian and Amazonian (stages 3 and 4) valleys originate within 100-200 km of three young, large impact craters and near rifts systems at Warrego Valles and the southern part of Coprates rise. These valleys likely developed when the cryosphere was a couple kilometers or more

  2. Planned updates and refinements to the Central Valley hydrologic model with an emphasis on improving the simulation of land subsidence in the San Joaquin Valley

    Science.gov (United States)

    Faunt, Claudia C.; Hanson, Randall T.; Martin, Peter; Schmid, Wolfgang

    2011-01-01

    California's Central Valley has been one of the most productive agricultural regions in the world for more than 50 years. To better understand the groundwater availability in the valley, the U.S. Geological Survey (USGS) developed the Central Valley hydrologic model (CVHM). Because of recent water-level declines and renewed subsidence, the CVHM is being updated to better simulate the geohydrologic system. The CVHM updates and refinements can be grouped into two general categories: (1) model code changes and (2) data updates. The CVHM updates and refinements will require that the model be recalibrated. The updated CVHM will provide a detailed transient analysis of changes in groundwater availability and flow paths in relation to climatic variability, urbanization, stream flow, and changes in irrigated agricultural practices and crops. The updated CVHM is particularly focused on more accurately simulating the locations and magnitudes of land subsidence. The intent of the updated CVHM is to help scientists better understand the availability and sustainability of water resources and the interaction of groundwater levels with land subsidence.

  3. Dynamics of Agricultural Groundwater Extraction

    NARCIS (Netherlands)

    Hellegers, P.J.G.J.; Zilberman, D.; Ierland, van E.C.

    2001-01-01

    Agricultural shallow groundwater extraction can result in desiccation of neighbouring nature reserves and degradation of groundwater quality in the Netherlands, whereas both externalities are often not considered when agricultural groundwater extraction patterns are being determined. A model is

  4. Geostatistical analysis of tritium, groundwater age and other noble gas derived parameters in California.

    Science.gov (United States)

    Visser, A; Moran, J E; Hillegonds, Darren; Singleton, M J; Kulongoski, Justin T; Belitz, Kenneth; Esser, B K

    2016-03-15

    Key characteristics of California groundwater systems related to aquifer vulnerability, sustainability, recharge locations and mechanisms, and anthropogenic impact on recharge are revealed in a spatial geostatistical analysis of a unique data set of tritium, noble gases and other isotopic analyses unprecedented in size at nearly 4000 samples. The correlation length of key groundwater residence time parameters varies between tens of kilometers ((3)H; age) to the order of a hundred kilometers ((4)Heter; (14)C; (3)Hetrit). The correlation length of parameters related to climate, topography and atmospheric processes is on the order of several hundred kilometers (recharge temperature; δ(18)O). Young groundwater ages that highlight regional recharge areas are located in the eastern San Joaquin Valley, in the southern Santa Clara Valley Basin, in the upper LA basin and along unlined canals carrying Colorado River water, showing that much of the recent recharge in central and southern California is dominated by river recharge and managed aquifer recharge. Modern groundwater is found in wells with the top open intervals below 60 m depth in the southeastern San Joaquin Valley, Santa Clara Valley and Los Angeles basin, as the result of intensive pumping and/or managed aquifer recharge operations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Geochemical Data on Waters, gases, scales, and rocks from the Dixie Valley Region, Nevada (1996-1999)

    Energy Technology Data Exchange (ETDEWEB)

    Goff, Fraser; Bergfeld, Deborah; Janik, C.J.; et al

    2002-08-01

    This report tabulates an extensive geochemical database on waters, gases, scales, rocks, and hot-spring deposits from the Dixie Valley region, Nevada. The samples from which the data were obtained were collected and analyzed during 1996 to 1999. These data provide useful information for ongoing and future investigations on geothermal energy, volcanism, ore deposits, environmental issues, and groundwater quality in this region.

  6. Hydrology of the San Luis Valley, south-central Colorado

    Science.gov (United States)

    Emery, P.A.; Boettcher, A.J.; Snipes, R.J.; Mcintyre, H.J.

    1969-01-01

    An investigation of the water resources of the Colorado part of the San Luis Valley was begun in 1966 by the U.S. Geological Survey, in cooperation with the Colorado Water Conservation Board. (See index map, fig. 1). The purpose of the investigation is to provide information for planning and implementing improved water-development and management practices. The major water problems in the San Luis Valley include (1) waterlogging, (2) waste of water by nonbeneficial evapotranspiration, (3) deterioration of ground-water chemical quality, and (4) failure of Colorado to deliver water to New Mexico and Texas in accordance with the Rio Grande Compact. This report describes the hydrologic environment, extent of water-resource development, and some of the problems related to that development. Information presented is based on data collected from 1966 to 1968 and on previous studies. Subsequent reports are planned as the investigation progresses. The San Luis Valley extends about 100 miles from Poncha Pass near the northeast corner of Saguache County, Colo., to a point about 16 miles south of the Colorado-New Mexico State line. The total area is 3,125 square miles, of which about 3,000 are in Colorado. The valley is nearly flat except for the San Luis Hills and a few other small areas. The Colorado part of the San Luis Valley, which is described in this report, has an average altitude of about 7,700 feet. Bounding the valley on the west are the San Juan Mountains and on the east the Sangre de Cristo Mountains. Most of the valley floor is bordered by alluvial fans deposited by streams originating in the mountains, the most extensive being the Rio Grande fan (see block diagram, fig. 2 in pocket). Most of the streamflow is derived from snowmelt from 4,700 square miles of watershed in the surrounding mountains. The northern half of the San Luis Valley is internally drained and is referred to as the closed basin. The lowest part of this area is known locally as the "sump." The

  7. Dark Valley in Newton Crater

    Science.gov (United States)

    2003-01-01

    MGS MOC Release No. MOC2-418, 11 July 2003This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) high resolution image shows part of a dark-floored valley system in northern Newton Crater. The valley might have been originally formed by liquid water; the dark material is probably sand that has blown into the valley in more recent times. The picture was acquired earlier this week on July 6, 2003, and is located near 39.2oS, 157.9oW. The picture covers an area 2.3 km (1.4 mi) across; sunlight illuminates the scene from the upper left.

  8. 27 CFR 9.41 - Lancaster Valley.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Lancaster Valley. 9.41... Lancaster Valley. (a) Name. The name of the viticultural area described in this section is “Lancaster Valley.” (b) Approved maps. The appropriate maps for determining the boundaries of the Lancaster Valley...

  9. Groundwater Availability Within the Salton Sea Basin Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Tompson, A; Demir, Z; Moran, J; Mason, D; Wagoner, J; Kollet, S; Mansoor, K; McKereghan, P

    2008-01-11

    It is widely recognized that increasing demands for water in Southern California are being affected by actions to reduce and redirect the amount of water imported from the Colorado River. In the Imperial Valley region, for example, import reductions will not only affect agricultural users but also could produce significant collateral impacts on the level and quality of water in the Salton Sea, its regional ecology, or even the long term air quality in the greater basin. The notion of using groundwater in the Imperial Valley as an additional source for agricultural or domestic needs, energy production, or Salton Sea restoration efforts, so as to offset reductions in imported water, is not a new concept. Even though it has been discussed recently (e.g., LLNL, 2002), the idea goes back, in part, to several studies performed by the US Department of Interior and other agencies that have indicated that there may be substantial, usable amounts of groundwater in some portions of the Imperial Valley. It has been estimated, for example, that between 1.1 and 3 billion acre-feet (AF) of groundwater lie within the extended, deep basin underlying the valley and Salton Sea region, even though much of it may be unrecoverable or too poor in its quality (Imperial County, 1997). This is a significant volume with respect to the total annual precipitation volume received in California, whose average is close to 200 million (or 0.2 billion) AF per year (DWR, 1998), and especially with respect to the total annual precipitation received in the Salton Sea watershed itself, which we estimate (Appendix A) to be approximately 2.5 million acre feet (MAF) per year. Clearly, a thorough appraisal of the groundwater resources in the Imperial Valley and Salton Sea region--i.e., an assessment of their overall physical availability--will be needed to determine how they can be used and managed to suit new or redirected demands in the region. Development of an improved or updated groundwater assessment

  10. Groundwater pollution microbiology

    Energy Technology Data Exchange (ETDEWEB)

    Bitton, G.; Gerba, C.P.

    1984-01-01

    This book provides a survey of available information on groundwater pollution microbiology. It is useful as a starting point for students and professionals investigating this topic. Subjects discussed include bacteria and virus movement through soils, carcinogenicity of some organic chemicals detected in groundwater, sampling techniques, and land treatment systems. Include references to the journal literature and a subject index.

  11. Groundwater Assessment Platform

    OpenAIRE

    Podgorski, Joel; Berg, Michael

    2018-01-01

    The Groundwater Assessment Platform is a free, interactive online GIS platform for the mapping, sharing and statistical modeling of groundwater quality data. The modeling allows users to take advantage of publicly available global datasets of various environmental parameters to produce prediction maps of their contaminant of interest.

  12. Human health and groundwater

    Science.gov (United States)

    The high quality of most groundwaters, consequent upon the self-purification capacity of subsurface strata, has long been a key factor in human health and wellbeing. More than 50% of the world’s population now rely on groundwater for their supply of drinking water – and in most circumstances a prope...

  13. Hydrogeological Characterization of the Middle Magdalena Valley - Colombia

    Science.gov (United States)

    Arenas, Maria Cristina; Riva, Monica; Donado, Leonardo David; Guadagnini, Alberto

    2017-04-01

    We provide a detailed hydrogeological characterization of the complex aquifer system of the Middle Magdalena Valley, Colombia. The latter is comprised by 3 sub-basins within which 7 blocks have been identified for active exploration and potential production of oil and gas. As such, there is a critical need to establish modern water resources management practices in the area to accommodate the variety of social, environmental and industrial needs. We do so by starting from a detailed hydrogeological characterization of the system and focus on: (a) a detailed hydrogeological reconnaissance of the area leading to the definition of the main hydrogeological units; (b) the collection, organization and analysis of daily climatic data from 39 stations available in the region; and (c) the assessment of the groundwater flow circulation through the formulation of a conceptual and a mathematical model of the subsurface system. Groundwater flow is simulated in the SAM 1.1 aquifer located in the Middle Magdalena Valley with the objective of showing and evaluating alternative conceptual hydrogeological modeling alternatives. We focus here on modeling results at system equilibrium (i.e., under steady-state conditions) and assess the value of available information in the context of the candidate modeling strategies we consider. Results of our modeling effort are conducive to the characterization of the distributed hydrogeological budget and the assessment of critical areas as a function of the conceptualization of the system functioning and data avilability.

  14. Recharging California's Groundwater: Crop Suitability and Surface Water Availability for Agricultural Groundwater Banking

    Science.gov (United States)

    Dahlke, H. E.; Kocis, T. N.; Brown, A.

    2016-12-01

    Groundwater banking, the intentional recharge of groundwater from surface water for storage and recovery, is an important conjunctive use strategy for water management in California (CA). A largely unexplored approach to groundwater banking, agricultural groundwater banking (ag-GB), utilizes flood flows and agricultural lands (alfalfa/pasture) for recharging groundwater. Understanding soil suitability for ag-GB, crop health and flooding tolerance, leaching of soil nitrate and salts, the availability of surface water for recharge, and the economic costs and benefits of ag-GB is fundamental to assessing the feasibility of local-scale implementation of ag-GB. The study presented here considers both the availability of excess streamflow (e.g., the magnitude, frequency, timing, and duration of winter flood flow) for ag-GB and the risks and benefits associated with using alfalfa fields as spreading grounds for ag-GB. The availability of surface water for winter (Nov to Apr) ag-GB were estimated based on daily streamflow records for 93 stream gauges within the Central Valley, CA. Analysis focused on high-magnitude (>90thpercentile) flows because most lower flows are likely legally allocated in CA. Results based >50 years of data indicate that an average winter/spring (Nov. - Apr.) in the Sacramento River Basin could provide 7 million acre-feet (AF) (8.6 km3) of water for ag-GB from flows above the 90th percentile. These flows originate from few storm events (5-7 events) and occur on average for 25-30 days between November and April. Wintertime on-farm recharge experiments were conducted on a 9-yr old, 15-acre alfalfa field in the Scott Valley, CA, where 135 AF and 107 AF of water were recharged during the winters of 2015 and 2016, respectively. Biomass data collected indicates that pulsed application of 6-10 ft of water on dormant alfalfa results in minimal yield loss (0.5 ton/acre reduction), short-duration saturated conditions in the root-zone, and high recharge

  15. High-resolution seismic reflection/refraction imaging from Interstate 10 to Cherry Valley Boulevard, Cherry Valley, Riverside County, California: implications for water resources and earthquake hazards

    Science.gov (United States)

    Gandhok, G.; Catchings, R.D.; Goldman, M.R.; Horta, E.; Rymer, M.J.; Martin, P.; Christensen, A.

    1999-01-01

    This report is the second of two reports on seismic imaging investigations conducted by the U.S. Geological Survey (USGS) during the summers of 1997 and 1998 in the Cherry Valley area in California (Figure 1a). In the first report (Catchings et al., 1999), data and interpretations were presented for four seismic imaging profiles (CV-1, CV-2, CV-3, and CV-4) acquired during the summer of 1997 . In this report, we present data and interpretations for three additional profiles (CV-5, CV-6, and CV-7) acquired during the summer of 1998 and the combined seismic images for all seven profiles. This report addresses both groundwater resources and earthquake hazards in the San Gorgonio Pass area because the shallow (upper few hundred meters) subsurface stratigraphy and structure affect both issues. The cities of Cherry Valley and Beaumont are located approximately 130 km (~80 miles) east of Los Angeles, California along the southern alluvial fan of the San Bernardino Mountains (see Figure 1b). These cities are two of several small cities that are located within San Gorgonio Pass, a lower-lying area between the San Bernardino and the San Jacinto Mountains. Cherry Valley and Beaumont are desert cities with summer daytime temperatures often well above 100 o F. High water usage in the arid climate taxes the available groundwater supply in the region, increasing the need for efficient management of the groundwater resources. The USGS and the San Gorgonio Water District (SGWD) work cooperatively to evaluate the quantity and quality of groundwater supply in the San Gorgonio Pass region. To better manage the water supplies within the District during wet and dry periods, the SGWD sought to develop a groundwater recharge program, whereby, excess water would be stored in underground aquifers during wet periods (principally winter months) and retrieved during dry periods (principally summer months). The SGWD preferred a surface recharge approach because it could be less expensive than a

  16. Hydrologic models and analysis of water availability in Cuyama Valley, California

    Science.gov (United States)

    Hanson, R.T.; Flint, Lorraine E.; Faunt, Claudia C.; Gibbs, Dennis R.; Schmid, Wolfgang

    2014-01-01

    Changes in population, agricultural development practices (including shifts to more water-intensive crops), and climate variability are placing increasingly larger demands on available water resources, particularly groundwater, in the Cuyama Valley, one of the most productive agricultural regions in Santa Barbara County. The goal of this study was to produce a model capable of being accurate at scales relevant to water management decisions that could be considered in the evaluation of the sustainable water supply. The Cuyama Valley Hydrologic Model (CUVHM) was designed to simulate the most important natural and human components of the hydrologic system, including components dependent on variations in climate, thereby providing a reliable assessment of groundwater conditions and processes that can inform water users and help to improve planning for future conditions. Model development included a revision of the conceptual model of the flow system, construction of a precipitation-runoff model using the Basin Characterization Model (BCM), and construction of an integrated hydrologic flow model with MODFLOW-One-Water Hydrologic Flow Model (MF-OWHM). The hydrologic models were calibrated to historical conditions of water and land use and, then, used to assess the use and movement of water throughout the Valley. These tools provide a means to understand the evolution of water use in the Valley, its availability, and the limits of sustainability. The conceptual model identified inflows and outflows that include the movement and use of water in both natural and anthropogenic systems. The groundwater flow system is characterized by a layered geologic sedimentary sequence that—in combination with the effects of groundwater pumping, natural recharge, and the application of irrigation water at the land surface—displays vertical hydraulic-head gradients. Overall, most of the agricultural demand for water in the Cuyama Valley in the initial part of the growing season is

  17. The Drentsche Aa valley system

    International Nuclear Information System (INIS)

    Gans, W. de.

    1981-01-01

    This thesis is composed of five papers concerned with Late Quaternary geology and geomorphology of the Aa valley system. The correlation and chronostratigraphic position of the layers have been established by radiocarbon dating. (Auth.)

  18. Structure and Velocities of the Northeastern Santa Cruz Mountains and the Western Santa Clara Valley, California, from the SCSI-LR Seismic Survey

    Science.gov (United States)

    Catchings, R.D.; Goldman, M.R.; Gandhok, G.

    2006-01-01

    Introduction: The Santa Clara Valley is located in the southern San Francisco Bay area of California and generally includes the area south of the San Francisco Bay between the Santa Cruz Mountains on the southwest and the Diablo Ranges on the northeast. The area has a population of approximately 1.7 million including the city of San Jose, numerous smaller cities, and much of the high-technology manufacturing and research area commonly referred to as the Silicon Valley. Major active strands of the San Andreas Fault system bound the Santa Clara Valley, including the San Andreas fault to the southwest and the Hayward and Calaveras faults to the northeast; related faults likely underlie the alluvium of the valley. This report focuses on subsurface structures of the western Santa Clara Valley and the northeastern Santa Cruz Mountains and their potential effects on earthquake hazards and ground-water resource management in the area. Earthquake hazards and ground-water resources in the Santa Clara Valley are important considerations to California and the Nation because of the valley's preeminence as a major technical and industrial center, proximity to major earthquakes faults, and large population. To assess the earthquake hazards of the Santa Clara Valley better, the U.S. Geological Survey (USGS) has undertaken a program to evaluate potential earthquake sources and potential effects of strong ground shaking within the valley. As part of that program, and to better assess water resources of the valley, the USGS and the Santa Clara Valley Water District (SCVWD) began conducting collaborative studies to characterize the faults, stratigraphy, and structures beneath the alluvial cover of the Santa Clara Valley in the year 2000. Such geologic features are important to both agencies because they directly influence the availability and management of groundwater resources in the valley, and they affect the severity and distribution of strong shaking from local or regional

  19. Cleanup and valuation of waters of the aquifer of M’zab Valley (Algeria

    Directory of Open Access Journals (Sweden)

    Ouled Belkhir Cheikh

    2016-06-01

    Full Text Available The M’zab valley is a hyper arid region of average rainfall not exceeding 100 mm per year. However, the rare floods that occur in M’zab River drain large volumes of surface water. Thanks to the genius of the local population, traditional dams were made for artificial recharge of groundwater. Grace of traditional wells drilled in the valley, farmers irrigate their palm groves and gardens. However, since more than half a century, the contribution of deep drilling for the exploitation of the aquifer of the Continental Intercalary posed environmental problems. On the basis of investigations and surveys of the local population during the years 2010, 2011, 2012 and 2013, it appears that these modern techniques in water catchment caused harmful consequences to the region like the rising of water consumption, pollution of groundwater and soil salinity. Solutions and recommendations are outlined in this article.

  20. Trends in groundwater quality in relation to groundwater age

    NARCIS (Netherlands)

    Visser, A.|info:eu-repo/dai/nl/318725371

    2009-01-01

    Groundwater is a valuable natural resource and as such should be protected from chemical pollution. Because of the long travel times of pollutants through groundwater bodies, early detection of groundwater quality deterioration is necessary to efficiently protect groundwater bodies. The aim of this

  1. InSAR to support sustainable urbanization over compacting aquifers: The case of Toluca Valley, Mexico

    Science.gov (United States)

    Castellazzi, Pascal; Garfias, Jaime; Martel, Richard; Brouard, Charles; Rivera, Alfonso

    2017-12-01

    This paper illustrates how InSAR alone can be used to delineate potential ground fractures related to aquifer system compaction. An InSAR-derived ground fracturing map of the Toluca Valley, Mexico, is produced and validated through a field campaign. The results are of great interest to support sustainable urbanization and show that InSAR processing of open-access Synthetic Aperture Radar (SAR) data from the Sentinel-1 satellites can lead to reliable and cost-effective products directly usable by cities to help decision-making. The Toluca Valley Aquifer (TVA) sustains the water needs of two million inhabitants living within the valley, a growing industry, an intensively irrigated agricultural area, and 38% of the water needs of the megalopolis of Mexico City, located 40 km east of the valley. Ensuring water sustainability, infrastructure integrity, along with supporting the important economic and demographic growth of the region, is a major challenge for water managers and urban developers. This paper presents a long-term analysis of ground fracturing by interpreting 13 years of InSAR-derived ground displacement measurements. Small Baseline Subset (SBAS) and Persistent Scatterer Interferometry (PSI) techniques are applied over three SAR datasets totalling 93 acquisitions from Envisat, Radarsat-2, and Sentinel-1A satellites and covering the period from 2003 to 2016. From 2003 to 2016, groundwater level declines of up to 1.6 m/yr, land subsidence up to 77 mm/yr, and major infrastructure damages are observed. Groundwater level data show highly variable seasonal responses according to their connectivity to recharge areas. However, the trend of groundwater levels consistently range from -0.5 to -1.5 m/yr regardless of the well location and depth. By analysing the horizontal gradients of vertical land subsidence, we provide a potential ground fracture map to assist in future urban development planning in the Toluca Valley.

  2. Hydrogeologic framework of the Wood River Valley aquifer system, south-central Idaho

    Science.gov (United States)

    Bartolino, James R.; Adkins, Candice B.

    2012-01-01

    The Wood River Valley contains most of the population of Blaine County and the cities of Sun Valley, Ketchum, Hailey, and Bellevue. This mountain valley is underlain by the alluvial Wood River Valley aquifer system, which consists primarily of a single unconfined aquifer that underlies the entire valley, an underlying confined aquifer that is present only in the southernmost valley, and the confining unit that separates them. The entire population of the area depends on groundwater for domestic supply, either from domestic or municipal-supply wells, and rapid population growth since the 1970s has caused concern about the long-term sustainability of the groundwater resource. As part of an ongoing U.S. Geological Survey effort to characterize the groundwater resources of the Wood River Valley, this report describes the hydrogeologic framework of the Wood River Valley aquifer system. Although most of the Wood River Valley aquifer system is composed of Quaternary-age sediments and basalts of the Wood River Valley and its tributaries, older igneous, sedimentary, or metamorphic rocks that underlie these Quaternary deposits also are used for water supply. It is unclear to what extent these rocks are hydraulically connected to the main part of Wood River Valley aquifer system and thus whether they constitute separate aquifers. Paleozoic sedimentary rocks in and near the study area that produce water to wells and springs are the Phi Kappa and Trail Creek Formations (Ordovician and Silurian), the Milligen Formation (Devonian), and the Sun Valley Group including the Wood River Formation (Pennsylvanian-Permian) and the Dollarhide Formation (Permian). These sedimentary rocks are intruded by granitic rocks of the Late Cretaceous Idaho batholith. Eocene Challis Volcanic Group rocks overlie all of the older rocks (except where removed by erosion). Miocene Idavada Volcanics are found in the southern part of the study area. Most of these rocks have been folded, faulted, and

  3. Saline groundwater in crystalline bedrock

    International Nuclear Information System (INIS)

    Lampen, P.

    1992-11-01

    The State-of-art report describes research made on deep saline groundwaters and brines found in crystalline bedrock, mainly in site studies for nuclear waste disposal. The occurrence, definitions and classifications of saline groundwaters are reviewed with a special emphasis on the different theories concerning the origins of saline groundwaters. Studies of the saline groundwaters in Finland and Sweden have been reviewed more thoroughly. Also the mixing of different bodies of groundwaters, observations of the contact of saline groundwaters and permafrost, and the geochemical modelling of saline groundwaters as well as the future trends of research have been discussed. (orig.)

  4. Preliminary appraisal of ground water in and near the ancestral Missouri River Valley, northeastern Montana

    Science.gov (United States)

    Levings, G.W.

    1986-01-01

    A preliminary appraisal was conducted in and near the ancestral Missouri River valley in northeastern Montana to describe the groundwater resources and to establish a data base for the area. The data base then could be used for future evaluation of possible changes in water levels or water quality. In this area, consolidated aquifers are the Upper Cretaceous Fox Hills-lower Hell Creek aquifer and the overlying Paleocene Fort Union Formation. Unconsolidated aquifers are Pleistocene terrace gravel and glacial deposits and Holocene alluvial deposits. Aquifers are recharged by precipitation, infiltration of streamflow, and possibly leakage from lakes and potholes. Groundwater moves from topographically higher areas to the ancestral valley, then along the ancestral valley to the southwest. Water is discharged from aquifers by evapotranspiration, springs and seeps, movement directly into streams and lakes, and from pumping wells. Average well yields are greatest for irrigation wells completed in outwash gravel (886 gallons/min). Eighteen wells were completed in various aquifers to monitor potential long-term changes in water levels and water quality. Measured water levels declined about 2 ft. or less during the study (1982-85). Chemical analysis of groundwater samples indicated that concentrations of some dissolved constituents exceeded U.S. Environmental Protection Agency standards for drinking water. (USGS)

  5. A hydrogeologic map of the Death Valley region, Nevada, and California, developed using GIS techniques

    Energy Technology Data Exchange (ETDEWEB)

    Faunt, C.C.; D`Agnese, F.A.; Turner, A.K.

    1997-12-31

    In support of Yucca Mountain site characterization studies, a hydrogeologic framework was developed, and a hydrogeologic map was constructed for the Death Valley region. The region, covering approximately 100,000 km{sup 2} along the Nevada-California border near Las Vegas, is characterized by isolated mountain ranges juxtaposed against broad, alluvium-filled valleys. Geologic conditions are typical of the Basin and Range Province; a variety of sedimentary and igneous intrusive and extrusive rocks have been subjected to both compressional and extensional deformation. The regional ground-water flow system can best be described as a series of connected intermontane basins in which ground-water flow occurs in basin-fill deposits, carbonate rocks, clastic rocks, and volcanic rocks. Previous investigations have developed more site-specific hydrogeologic relationships; however, few have described all the lithologies within the Death Valley regional ground-water flow system. Information required to characterize the hydrogeologic units in the region was obtained from regional geologic maps and reports. Map data were digitized from regional geologic maps and combined into a composite map using a geographic information system. This map was simplified to show 10 laterally extensive hydrogeologic units with distinct hydrologic properties. The hydraulic conductivity values for the hydrogeologic units range over 15 orders of magnitude due to the variability in burial depth and degree of fracturing.

  6. Airborne electromagnetic and magnetic survey data of the Paradox and San Luis Valleys, Colorado

    Science.gov (United States)

    Ball, Lyndsay B.; Bloss, Benjamin R.; Bedrosian, Paul A.; Grauch, V.J.S.; Smith, Bruce D.

    2015-01-01

    In October 2011, the U.S. Geological Survey (USGS) contracted airborne magnetic and electromagnetic surveys of the Paradox and San Luis Valleys in southern Colorado, United States. These airborne geophysical surveys provide high-resolution and spatially comprehensive datasets characterizing the resistivity structure of the shallow subsurface of each survey region, accompanied by magnetic-field information over matching areas. These data were collected to provide insight into the distribution of groundwater brine in the Paradox Valley, the extent of clay aquitards in the San Luis Valley, and to improve our understanding of the geologic framework for both regions. This report describes these contracted surveys and releases digital data supplied under contract to the USGS.

  7. Diverse stakeholders create collaborative, multilevel basin governance for groundwater sustainability

    Directory of Open Access Journals (Sweden)

    Esther Conrad

    2018-01-01

    Full Text Available The Sustainable Groundwater Management Act (SGMA is introducing significant changes in the way groundwater is governed for agricultural use. It requires the formation of groundwater sustainability agencies (GSAs to manage groundwater basins for sustainability with the engagement of all users. That presents opportunities for collaboration, as well as challenges, particularly in basins with large numbers of agricultural water users who have longstanding private pumping rights. The GSA formation process has resulted in the creation of multiple GSAs in many such basins, particularly in the Central Valley. In case studies of three basins, we examine agricultural stakeholders' concerns about SGMA, and how these are being addressed in collaborative approaches to groundwater basin governance. We find that many water districts and private pumpers share a strong interest in maintaining local autonomy, but they have distinct concerns and different options for forming and participating in GSAs. Multilevel collaborative governance structures may help meet SGMA's requirements for broad stakeholder engagement, our studies suggest, while also addressing concerns about autonomy and including agricultural water users in decision-making.

  8. Stable-isotope studies of groundwaters in southeastern New Mexico

    International Nuclear Information System (INIS)

    Lambert, S.J.

    1987-01-01

    Oxygen-18/16 and deuterium/hydrogen ratio measurements have been made on groundwaters sampled according to specific field criteria applied during pump tests of the Rustler Formation in Nash Draw, a solution-subsidence valley west of the WIPP site in the northern Delaware Basin of southeastern New Mexico. Comparison of these data with similar measurements on other groundwaters from the northern Delaware Basin indicates two nonoverlapping populations of meteoric groundwaters. Most of the Rustler waters in Nash Draw and at the WIPP site and older waters from the eastern two-thirds of the Capitan Limestone constitute one population, while unconfined groundwaters originating as observable modern surface recharge to alluvium, the near-surface Rustler in southwestern Nash Draw, and the Capitan in the Guadalupe Mountains (Carlsbad Caverns) constitute the other. The isotopic distinction suggests that Rustler groundwater in most of Nash Draw and at the WIPP site is not receiving significant modern meteoric recharge. A likely explanation for this distinction is that meteoric recharge to most of the Rustler and Capitan took place in the geologic past under climatic conditions significantly different from the present. 25 refs., 4 figs., 2 tabs

  9. Oak Ridge Y-12 Plant groundwater protection program management plan

    International Nuclear Information System (INIS)

    1996-06-01

    The Oak Ridge Y- 1 2 Plant (Y-12 Plant) is owned by the United States Department of Energy (DOE) and managed by Lockheed Martin Energy Systems, Inc. (Energy Systems) under contract No. DE-AC05-84OR21400. The Y-12 Plant Groundwater Protection Program (GWPP), which was initiated in 1975, provides for the protection of groundwater resources consistent with Federal, State, and local regulations, and in accordance with DOE orders and Energy Systems policies and procedures. The Y-12 Plant is located in Anderson County, Tennessee, and is within the corporate limits of the City of Oak Ridge. The Y-12 Plant is one of three major DOE complexes that comprise the 37,000-acre Oak Ridge Reservation (ORR) located in Anderson and Roane counties. The Y-12 Plant is located in Bear Creek Valley at an elevation of about 950 feet (ft) above sea level. Bear Creek Valley is bounded on the northwest and southeast, and is isolated from populated areas of Oak Ridge, by parallel ridges that rise about 300 ft above the valley floor. The Y-12 Plant and its fenced buffer area are about 0.6 mile wide by 3.2 miles long and cover approximately 4,900 acres. The main industrialized section encompasses approximately 800 acres

  10. The use of 18O as a groundwater tracer in the Marlborough Region

    International Nuclear Information System (INIS)

    Stewart, M.K.

    2006-01-01

    The usefulness of 18 O for monitoring groundwater wells in the Wairau River coastal plain has been investigated by conducting a survey of the wells used for monitoring. The δ 18 O values of the Wairau Aquifer well waters show trends along the lines of flow depending on distance and depth. Near the head of the valley and close to the river, the groundwater has δ 18 O values like that of the Wairau River. With distance from the river and towards the coast, the δ 18 O values of shallow groundwater in the unconfined aquifer become more positive as land surface infiltrating recharge with higher δ 18 O values contributes to the flow. The infiltrating water also carries nitrate and other chemicals to the groundwater. At deeper levels, the groundwater is not affected by water infiltrating through the surface, and retains its Wairau River δ 18 O signature when it rises towards the surface near the coast. However, this conclusion is regarded as preliminary because of the possible temporal variability of the groundwater δ 18 O values. Regular 3-monthly 18 O measurements should be carried out on 8 key wells to substantiate this conclusion. The δ 18 O values of the southern valley aquifer waters indicate that they are sourced from local streams and surface recharge. The Rarangi and Tuamarina aquifers are sourced from local rainfall with δ 18 O of -6.2 permille. (author). 5 refs., 3 figs., 2 tabs

  11. Monitoring of the Syrian rift valley using radon technique

    International Nuclear Information System (INIS)

    Al-Hilal, M.; Al-Ali, A.; Jubeli, Y.

    1997-02-01

    Groundwater radon data were recorded once every two months from six monitoring sites of the Syrian rift valley during the year 1996. Radon samples were measured from deep artesian wells and from continuously-flowing springs that are distributed along this most active seismic zone in Syria. The available data were integrated with previously measured groundwater radon data from the same stations in order to estimate the range of normal radon fluctuations in the region. The estimation of such range may enable the separation between usual groundwater radon variations from other outliers which may indicate possible tectonic activities or earthquake hazards in the study area. Periodical radon measurements based on two months intervals and long distance between sampling stations does not enable us to trust with high level of confidence the connection between radon values and any possible earth dynamics. Therefore, shorter measuring time with closer monitoring sites are highly recommended to achieve the optimum advantage of such application. (Author). 8 Figs., 2 Tabs., 10 Refs

  12. Hydrogeology of a drift-filled bedrock valley near Lino Lakes, Anoka County, Minnesota

    Science.gov (United States)

    Winter, T.C.; Pfannkuch, H.O.

    1976-01-01

    The bedrock surface of east-central Minnesota is dissected by an intricate network of valleys. Outside the bedrock valley at site B, 3 mi (4. 8 km) from site A, 100 ft (30 m) of drift overlies the bedrock surface. Observation wells were installed at the two sites to determine the vertical ground-water movement between the various aquifer units and the lateral movement between the two sites. An aquifer test of the lowest valley-fill aquifer at site A showed that the observation well completed in the same aquifer as the pumping well responded immediately; whereas a lag of about 100 min occurred between the lower valley fill and uppermost body of sand and gravel. This indicates that the hydraulic connection between these two layers is poor at the immediate site. Test results show that the lower sand-and-gravel aquifer has a transmissivity between 14,000 and 27,000 ft2/d (1,300 and 2,500 m2/d). Although the hydraulic gradient is vertically downward in the valley, much of the drift fill is poorly permeable. This suggests that the quantity of downward-percolating water reaching the lowest valley-fill aquifer is relatively small at the test site. Because valley cut through a number of bedrock aquifers in the region, they could potentially be an important avenue of contamination from land-surface waste. In addition, the vast network of bedrock valleys in the Twin Cities area might cause contaminants to disseminate rather rapidly throughout a large area.

  13. Numerical Modeling of Regional Groundwater Flow in a Structurally Complex Intermountain Basin: South Park, Colorado

    Science.gov (United States)

    Ball, L. B.; Caine, J. S.; Ge, S.

    2012-12-01

    A steady-state, 3-D groundwater flow model of the South Park basin was developed to explore the influence of realistically complex topography and permeability structure on the patterns of basin-wide groundwater flow and to evaluate the sensitivity of the groundwater flow system to increased variability in recharge distribution and the influence of hydrogeologically distinct fault zones. South Park is a large, semi-arid intermountain basin (3300 km2) flanked by crystalline rocks and floored with faulted and folded sedimentary rocks and volcanic deposits. Model results suggest that, while the majority (>80%) of water entering the groundwater flow system is discharged through seepage faces in steep terrain or routed to mountain streams, internal exchanges of groundwater and stream flow between the mountain and valley landscapes are an important part of the dynamics of groundwater flow in the basin. The majority of topographically driven groundwater flow is focused in the upper 300 m of the model domain and would be considered local to intermediate in "Tothian" scales. Less than 1% of groundwater flow passes below 1 km in depth, and large-scale regional circulation is a limited component of the groundwater flow system. Increasingly heterogeneous recharge distributions most heavily impacted the groundwater flow system at the local scale, while basin-wide regional flow remained relatively insensitive to the increasing variability in recharge distribution. The introduction of end-member conduit and barrier types of fault zones influenced hydraulic heads and gradients within 5-10 km of the fault location where groundwater flow directions are perpendicular to the orientation of the fault. Where groundwater flow directions are oblique or subparallel to the fault, the introduction of distinct fault zones had a negligible impact on hydraulic heads or gradients.

  14. Groundwater Capture Zones

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — Source water protection areas are delineated for each groundwater-based public water supply system using available geologic and hydrogeologic information to...

  15. Groundwater management in France

    Science.gov (United States)

    Margat, Jean

    1987-06-01

    Groundwater, like other extensive natural and renewable resources, easily accessible and, at the same time, vulnerable, has to be managed so as to reconcile the unique resource with its many users, and its long-term preservation with short-term utilization requirements. Under the natural, legal, and economic conditions prevailing in France, where groundwater constitutes a large part of water production and resources, where there are tens of thousands of economic developers and users of a few hundred natural groundwater management units, such management concerns these users as well as the public and collective authorities that control the users' activities for the common present and future good of all. Legislative, financial, and educational means are applied simultaneously to preserve and protect the quality and quantily of the groundwater and at times to encourage its use and stimulate its development.

  16. Wetland Groundwater Processes

    National Research Council Canada - National Science Library

    Williams, Greg

    1993-01-01

    This technical note summarizes hydrologic and hydraulic (H AND H) processes and the related terminology that will likely be encountered during an evaluation of the effect of ground-water processes on wetland function...

  17. Investigation of groundwater in the Upper Motueka River catchment

    International Nuclear Information System (INIS)

    Stewart, M.K.; Hong, T.Y.-S.; Cameron, S.C.; Daughney, C.J.; Tait, T.; Thomas, J.T.

    2005-01-01

    Groundwater investigation in the Upper Motueka catchment is a key end user-driven component of the Integrated Catchment Management (ICM) project, a six year programme which commenced in July 2000. The goal of the ICM project is to conduct multi-disciplinary, multi-stakeholder research to provide information and knowledge that will improve the management of land, freshwater, and near-coastal environments in catchments with multiple, interacting, and potentially conflicting land uses. The principal aims of the investigations are to understand the hydrogeology of the Upper Motueka valley (including parts of the Motupiko and Tadmor valleys), the aquifer hydraulic properties, the occurrence of groundwater (recharge, storage and discharge), and the connectivity to the rivers. Understanding these will give a conceptual model of the river/groundwater system to constrain computational models. The study area lies within the Moutere Depression at lower altitude and has moderate rainfall (900-1300 mm). Higher land to the east with rainfall up to 2000 mm feeds the upper reaches of the Motueka River. Comparison of the Motueka River flow at the gorge and upstream of the Wangapeka River confluence shows that much of the flow, and particularly much of the low flow, are generated within the comparatively small gorge headwater area, comprising ultramafics and Maitai Group sediments. Below the gorge, the catchment contains Moutere Gravel. The Motupiko and Tadmor catchments are predominantly Moutere Gravel. (author). 13 refs., figs., tabs

  18. Gases in groundwater

    International Nuclear Information System (INIS)

    Vogel, J.C.; Heaton, T.H.E.

    1979-01-01

    Contributing to both economic and environmental spheres, radon and helium contained in groundwater are being used to detect uranium mineralisation and in conjunction with other gases, to locate natural gas and oil deposits; they are also helping to unravel the earth's past climatic history. Analysis of the gases dissolved in groundwater is proving useful in widely different fields ranging from uranium exploration, to earthquake prediction and the determination of palaeotemperatures [af

  19. Human health and groundwater

    OpenAIRE

    Candela Lledó, Lucila

    2016-01-01

    Strategic overview series of the International Association of Hydrogeologists-IAH. This Series is designed both to inform professionals in other sectors of key interactions with groundwater resources and hydrogeological science, and to guide IAH members in their outreach to related sectors. The naturally high microbiological and chemical quality of groundwater, captured at springheads and in shallow galleries and dugwells, has been vital for human survival, wellbeing and development from o...

  20. Integrated groundwater data management

    Science.gov (United States)

    Fitch, Peter; Brodaric, Boyan; Stenson, Matt; Booth, Nathaniel; Jakeman, Anthony J.; Barreteau, Olivier; Hunt, Randall J.; Rinaudo, Jean-Daniel; Ross, Andrew

    2016-01-01

    The goal of a data manager is to ensure that data is safely stored, adequately described, discoverable and easily accessible. However, to keep pace with the evolution of groundwater studies in the last decade, the associated data and data management requirements have changed significantly. In particular, there is a growing recognition that management questions cannot be adequately answered by single discipline studies. This has led a push towards the paradigm of integrated modeling, where diverse parts of the hydrological cycle and its human connections are included. This chapter describes groundwater data management practices, and reviews the current state of the art with enterprise groundwater database management systems. It also includes discussion on commonly used data management models, detailing typical data management lifecycles. We discuss the growing use of web services and open standards such as GWML and WaterML2.0 to exchange groundwater information and knowledge, and the need for national data networks. We also discuss cross-jurisdictional interoperability issues, based on our experience sharing groundwater data across the US/Canadian border. Lastly, we present some future trends relating to groundwater data management.

  1. Classification of groundwater at the Nevada Test Site

    International Nuclear Information System (INIS)

    Chapman, J.B.

    1994-08-01

    Groundwater occurring at the Nevada Test Site (NTS) has been classified according to the ''Guidelines for Ground-Water Classification Under the US Environmental Protection Agency (EPA) Ground-Water Protection Strategy'' (June 1988). All of the groundwater units at the NTS are Class II, groundwater currently (IIA) or potentially (IIB) a source of drinking water. The Classification Review Area (CRA) for the NTS is defined as the standard two-mile distance from the facility boundary recommended by EPA. The possibility of expanding the CRA was evaluated, but the two-mile distance encompasses the area expected to be impacted by contaminant transport during a 10-year period (EPA,s suggested limit), should a release occur. The CRA is very large as a consequence of the large size of the NTS and the decision to classify the entire site, not individual areas of activity. Because most activities are located many miles hydraulically upgradient of the NTS boundary, the CRA generally provides much more than the usual two-mile buffer required by EPA. The CRA is considered sufficiently large to allow confident determination of the use and value of groundwater and identification of potentially affected users. The size and complex hydrogeology of the NTS are inconsistent with the EPA guideline assumption of a high degree of hydrologic interconnection throughout the review area. To more realistically depict the site hydrogeology, the CRA is subdivided into eight groundwater units. Two main aquifer systems are recognized: the lower carbonate aquifer system and the Cenozoic aquifer system (consisting of aquifers in Quaternary valley fill and Tertiary volcanics). These aquifer systems are further divided geographically based on the location of low permeability boundaries

  2. Water and rock geochemistry, geologic cross sections, geochemical modeling, and groundwater flow modeling for identifying the source of groundwater to Montezuma Well, a natural spring in central Arizona

    Science.gov (United States)

    Johnson, Raymond H.; DeWitt, Ed; Wirt, Laurie; Arnold, L. Rick; Horton, John D.

    2011-01-01

    The National Park Service (NPS) seeks additional information to better understand the source(s) of groundwater and associated groundwater flow paths to Montezuma Well in Montezuma Castle National Monument, central Arizona. The source of water to Montezuma Well, a flowing sinkhole in a desert setting, is poorly understood. Water emerges from the middle limestone facies of the lacustrine Verde Formation, but the precise origin of the water and its travel path are largely unknown. Some have proposed artesian flow to Montezuma Well through the Supai Formation, which is exposed along the eastern margin of the Verde Valley and underlies the Verde Formation. The groundwater recharge zone likely lies above the floor of the Verde Valley somewhere to the north or east of Montezuma Well, where precipitation is more abundant. Additional data from groundwater, surface water, and bedrock geology are required for Montezuma Well and the surrounding region to test the current conceptual ideas, to provide new details on the groundwater flow in the area, and to assist in future management decisions. The results of this research will provide information for long-term water resource management and the protection of water rights.

  3. Using SWAT-MODFLOW to simulate groundwater flow and groundwater-surface water interactions in an intensively irrigated stream-aquifer system

    Science.gov (United States)

    Wei, X.; Bailey, R. T.

    2017-12-01

    Agricultural irrigated watersheds in semi-arid regions face challenges such as waterlogging, high soil salinity, reduced crop yield, and leaching of chemical species due to extreme shallow water tables resulting from long-term intensive irrigation. Hydrologic models can be used to evaluate the impact of land management practices on water yields and groundwater-surface water interactions in such regions. In this study, the newly developed SWAT-MODFLOW, a coupled surface/subsurface hydrologic model, is applied to a 950 km2 watershed in the Lower Arkansas River Valley (southeastern Colorado). The model accounts for the influence of canal diversions, irrigation applications, groundwater pumping, and earth canal seepage losses. The model provides a detailed description of surface and subsurface flow processes, thereby enabling detailed description of watershed processes such as runoff, infiltration, in-streamflow, three-dimensional groundwater flow in a heterogeneous aquifer system with sources and sinks (e.g. pumping, seepage to subsurface drains), and spatially-variable surface and groundwater exchange. The model was calibrated and tested against stream discharge from 5 stream gauges in the Arkansas River and its tributaries, groundwater levels from 70 observation wells, and evapotranspiration (ET) data estimated from satellite (ReSET) data during the 1999 to 2007 period. Since the water-use patterns within the study area are typical of many other irrigated river valleys in the United States and elsewhere, this modeling approach is transferable to other regions.

  4. Vulnerability assessment of the Toluca Valley aquifer combining a parametric approach and advective transport

    International Nuclear Information System (INIS)

    Gárfias, J.; Llanos, H.; Franco, R.; Martel, R.

    2017-01-01

    Groundwater vulnerability assessment is an important task in water resources and land management. Depending on the availability of data and the complexity of the hydrogeological conditions, different approaches can be adopted. As an alternative, this study involves the use of a combined approach based on vulnerability methods and advective particle tracking to better understand the susceptibility to contamination in the Toluca valley aquifer. An intrinsic vulnerability map (DRASTIC) was used to identify areas that are more susceptible to ground water contamination. To estimate advective particle tracking, we developed a 3D flow model using VisualModflow and MODPATH to describe the regional flow of groundwater. The vulnerability map demonstrates the problematic application and interpretation of qualitative the vulnerability method of the parametric system group, which indicates a difference of approximately 23% when compared with the modified vulnerability map. Potential contamination sources based on landfill sites were comparatively high; approximately 76% are located in areas that could be susceptible to contamination through vertical infiltration, especially those that are located along the Lerma system of wells. Industrial parks located in the centre of the valley (83%), where continuous extraction of groundwater and land subsidence occurs, have been classified as high vulnerability zones, increasing the risk of contaminants from surface sources reaching the groundwater. In order to understand the susceptibility to contamination in the aquifer, various delineation approaches should be adopted and all the results that validate each other should be considered, thus making a good strategy for implementing different degrees of protection measures. [es

  5. Groundwater origin and flow along selected transects in Ethiopian rift volcanic aquifers

    Science.gov (United States)

    Kebede, Seifu; Travi, Yves; Asrat, Asfawossen; Alemayehu, Tamiru; Ayenew, Tenalem; Tessema, Zenaw

    2008-02-01

    The disruption of lithologies by cross-cutting faults and the variability in volcanic structures make the hydrogeology of the rifted volcanic terrain in Ethiopia very complex. Along two transects, selected due to their hydrogeologic characteristics, groundwater flow, depth of circulation and geochemical evolution have been conceptualized. The groundwater flow continuity between the high rainfall plateau bounding the rift and the rift valley aquifers depends principally on the nature of the bounding faults. Up to 50% of recharge to the rift aquifers comes from the plateau as groundwater inflow where the rift is cross cut by transverse fault zones. Recharge from the mountains is found to be insignificant where the rift is bounded by marginal grabens; channel loss and local precipitation are the principal sources of recharge to the rift aquifers in such cases. At a regional scale, there is a clear zonation in the geochemical compositions of groundwaters, the result of aquifer matrix composition differences. The environmental isotope results show that the majority of the aquifers contain modern groundwaters. In a few localities, particularly in thermal groundwaters representing deeper circulation, palaeo-groundwaters have been identified. Deeper groundwaters in the rift floor have a uniform 14C age ranging between 2,300 and 3,000 years.

  6. Hydrogeology and water quality of the stratified-drift aquifer in the Pony Hollow Creek Valley, Tompkins County, New York

    Science.gov (United States)

    Bugliosi, Edward F.; Miller, Todd S.; Reynolds, Richard J.

    2014-01-01

    The lithology, areal extent, and the water-table configuration in stratified-drift aquifers in the northern part of the Pony Hollow Creek valley in the Town of Newfield, New York, were mapped as part of an ongoing aquifer mapping program in Tompkins County. Surficial geologic and soil maps, well and test-boring records, light detection and ranging (lidar) data, water-level measurements, and passive-seismic surveys were used to map the aquifer geometry, construct geologic sections, and determine the depth to bedrock at selected locations throughout the valley. Additionally, water-quality samples were collected from selected streams and wells to characterize the quality of surface and groundwater in the study area. Sedimentary bedrock underlies the study area and is overlain by unstratified drift (till), stratified drift (glaciolacustrine and glaciofluvial deposits), and recent post glacial alluvium. The major type of unconsolidated, water-yielding material in the study area is stratified drift, which consists of glaciofluvial sand and gravel, and is present in sufficient amounts in most places to form an extensive unconfined aquifer throughout the study area, which is the source of water for most residents, farms, and businesses in the valleys. A map of the water table in the unconfined aquifer was constructed by using (1) measurements made between the mid-1960s through 2010, (2) control on the altitudes of perennial streams at 10-foot contour intervals from lidar data collected by Tompkins County, and (3) water surfaces of ponds and wetlands that are hydraulically connected to the unconfined aquifer. Water-table contours indicate that the direction of groundwater flow within the stratified-drift aquifer is predominantly from the valley walls toward the streams and ponds in the central part of the valley where groundwater then flows southwestward (down valley) toward the confluence with the Cayuta Creek valley. Locally, the direction of groundwater flow is radially

  7. Geohydrology and Water Quality of the Valley-Fill Aquifer System in the Upper Sixmile Creek and West Branch Owego Creek Valleys in the Town of Caroline, Tompkins County, New York

    Science.gov (United States)

    Miller, Todd S.

    2009-01-01

    In 2002, the U.S. Geological Survey, in cooperation with the Town of Caroline and Tompkins County Planning Department, began a study of the valley-fill aquifer system in upper Sixmile Creek and headwaters of West Branch Owego Creek valleys in the Town of Caroline, NY. The purpose of the study is to provide geohydrologic data to county and town planners as they develop a strategy to manage and protect their water resources. The first aquifer reach investigated in this series is in the Town of Caroline and includes the upper Sixmile Creek valley and part of West Branch Owego Creek valley. The portions of the valley-fill aquifer system that are comprised of saturated coarse-grained sediments including medium to coarse sand and sandy gravel form the major aquifers. Confined sand and gravel units form the major aquifers in the western and central portions of the upper Sixmile Creek valley, and an unconfined sand and gravel unit forms the major aquifer in the eastern portion of the upper Sixmile Creek valley and in the headwaters of the West Branch Owego Creek valley. The valley-fill deposits are thinnest near the edges of the valley where they pinch out along the till-mantled bedrock valley walls. The thickness of the valley fill in the deepest part of the valley, at the western end of the study area, is about 100 feet (ft); the thickness is greater than 165 ft on top of the Valley Heads Moraine in the central part of the valley. An estimated 750 people live over and rely on groundwater from the valley-fill aquifers in upper Sixmile Creek and West Branch Owego Creek valleys. Most groundwater withdrawn from the valley-fill aquifers is pumped from wells with open-ended 6-inch diameter casings; the remaining withdrawals are from shallow dug wells or cisterns that collect groundwater that discharges to springs (especially in the Brooktondale area). The valley-fill aquifers are the sources of water for about 200 households, several apartment complexes, two mobile home parks

  8. Does groundwater enhance evaporative cooling?

    Science.gov (United States)

    Rouholahnejad, E.

    2015-12-01

    Evaporation is a key process in land-climate interactions, not only because it directly regulates the hydrological cycle, but also because it contributes to the Earth's energy balance. Due to its feedbacks on large-scale water processes and its impact on the dynamics of the atmosphere, it has been considered as a driver of droughts and heatwaves1-3. While evaporation from ocean surfaces is likely to increase with rising temperatures, it is unclear whether evapotranspiration from land surfaces could similarly increase, due to possible limitations imposed by soil moisture and vegetation physiology4. Observations suggest that groundwater (hereafter GW) has an important role in hydrological budgets and soil moisture variability in many regions, supplying moisture for evapotranspiration during dry seasons5, 6. Although modeling studies suggest that GW is often close enough to the surface to interact with the atmosphere7, 8, the soil water storage is often underestimated by land surface models. This is most likely due to neglecting the lateral movement of water from topographically higher altitudes to valley bottoms and its convergence close to the land surface, as well as the upward movement of water in the capillary fringe.The focus of this study is to understand where and when GW may significantly enhance the availability of soil water for evapotranspiration. We also quantified the potential contribution of GW to evapotranspiration in the areas where GW is a major supply. We used the global network of eddy covariance observations9 (FLUXNET) along with global modeled GW depth10 and GLEAM ET model estimates11 to address the current gap in modelling ET due to neglecting GW supply. Having identified areas where GW is tightly coupled with the atmosphere through evaporation processes, the study provides the basis to examine the "air conditioning effect" of GW and test the idea if GW enhances evaporation to the extent that leads to a cooler temperatures and wetter climates.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

  10. Water resources development in Santa Clara Valley, California: insights into the human-hydrologic relationship

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, Jesse L. [Univ. of California, Berkeley, CA (United States)

    2000-06-01

    Groundwater irrigation is critical to food production and, in turn, to humankind's relationship with its environment. The development of groundwater in Santa Clara Valley, California during the early twentieth century is instructive because (1) responses to unsustainable resource use were largely successful; (2) the proposals for the physical management of the water, although not entirely novel, incorporated new approaches which reveal an evolving relationship between humans and the hydrologic cycle; and (3) the valley serves as a natural laboratory where natural (groundwater basin, surface watershed) and human (county, water district) boundaries generally coincide. Here, I investigate how water resources development and management in Santa Clara Valley was influenced by, and reflective of, a broad understanding of water as a natural resource, including scientific and technological innovations, new management approaches, and changing perceptions of the hydrologic cycle. Market demands and technological advances engendered reliance on groundwater. This, coupled with a series of dry years and laissez faire government policies, led to overdraft. Faith in centralized management and objective engineering offered a solution to concerns over resource depletion, and a group dominated by orchardists soon organized, fought for a water conservation district, and funded an investigation to halt the decline of well levels. Engineer Fred Tibbetts authored an elaborate water salvage and recharge plan that optimized the local water resources by integrating multiple components of the hydrologic cycle. Informed by government investigations, groundwater development in Southern California, and local water law cases, it recognized the limited surface storage possibilities, the spatial and temporal variability, the relatively closed local hydrology, the interconnection of surface and subsurface waters, and the value of the groundwater basin for its storage, transportation, and

  11. Water resources of the Lower Rio Grande de Arecibo alluvial valley, Puerto Rico

    Science.gov (United States)

    Quinones-Aponte, Vicente

    1986-01-01

    An assessment of the surface and groundwater resources of the lower Rio Grande de Arecibo alluvial valley was made between 1981 and 1983. Rio Grande de Arecibo is the major source of water in the valley with a mean-annual discharge of 527 cu ft/sec (382,000 acre-ft/yr). Its lowest mean-daily flow (low flow) during 12 yr of record is 50 cu ft/sec. Withdrawals of water from Rio Grande de Arecibo exceeding 15 cu ft/sec during periods of extreme low flows could cause reduction of recharge to the aquifer. However, withdrawals of as much as 35 cu ft/sec are possible when base flow ranges from 90 to 200 cu ft/sec without causing a reduction of aquifer recharge. An unconfined aquifer within the alluvial valley is hydraulically continuous with bordering limestone formations. A clay layer divides the alluvial aquifer into two separate hydraulic systems. Groundwater from the alluvial aquifer above the clay layer has not been widely developed. However, high yielding wells presently yield as much as 9.6 mil gal/day (10,800 acre-ft/yr) from the aquifers occurring below the clay layer within the alluvium and underlaying limestones. Transmissivity ranges from 3,000 sq ft/day in the alluvial area to 42,000 sq ft/day in the adjacent limestone areas. Total groundwater flow through aquifers within the study area (excluding water withdrawn by wells) is about 20.6 mil gal/day (23,100 acre-ft/yr). 50% of this amount is estimated to flow to the eastern area of Cano Tiburones and discharges as springs and seeps. An estimated 9.4 mil gal/day (10,500 acre-ft/yr) of additional groundwater can be withdrawn from the aquifers below the clay layer without reversing the northward hydraulic gradient. Seepage from Rio Grande de Arecibo to the groundwater system at the east side of the valley is probably the key to the development of groundwater resources in the Arecibo area. San Pedro spring, with an average discharge of 8.6 mil gal/day (9,600 acre-ft/yr), is undeveloped and represents a potential

  12. Valley Fever (Coccidioidomycosis) Risk and Prevention

    Science.gov (United States)

    ... valley fever, but it is not contagious between animals and people. Valley fever in dogs is similar to valley ... Via Growth on Fomites. An Epidemic Involving Six Persons. Am Rev Respir Dis. ... aspects of coccidioidomycosis in animals and humans. Ann N Y Acad Sci. 2007 ...

  13. Evapotranspiration Within the Groundwater Model Domain of the Tuba City, Arizona, Disposal Site Interim Report

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2015-03-01

    The revised groundwater model includes estimates of evapotranspiration (ET). The types of vegetation and the influences of ET on groundwater hydrology vary within the model domain. Some plant species within the model domain, classified as phreatophytes, survive by extracting groundwater. ET within these plant communities can result in a net discharge of groundwater if ET exceeds precipitation. Other upland desert plants within the model domain survive on meteoric water, potentially limiting groundwater recharge if ET is equivalent to precipitation. For all plant communities within the model domain, excessive livestock grazing or other disturbances can tip the balance to a net groundwater recharge. This task characterized and mapped vegetation within the groundwater model domain at the Tuba City, Arizona, Site, and then applied a remote sensing algorithm to estimate ET for each vegetation type. The task was designed to address five objectives: 1. Characterize and delineate different vegetation or ET zones within the groundwater model domain, focusing on the separation of plant communities with phreatophytes that survive by tapping groundwater and upland plant communities that are dependent on precipitation. 2. Refine a remote sensing method, developed to estimate ET at the Monument Valley site, for application at the Tuba City site. 3. Estimate recent seasonal and annual ET for all vegetation zones, separating phreatophytic and upland plant communities within the Tuba City groundwater model domain. 4. For selected vegetation zones, estimate ET that might be achieved given a scenario of limited livestock grazing. 5. Analyze uncertainty of ET estimates for each vegetation zone and for the entire groundwater model domain.

  14. Geologic characterization report for the Paradox Basin Study Region, Utah Study Areas. Volume 6. Salt Valley

    International Nuclear Information System (INIS)

    1984-12-01

    Surface landforms in the Salt Valley Area are generally a function of the Salt Valley anticline and are characterized by parallel and subparallel cuestaform ridges and hogbacks and flat valley floors. The most prominent structure in the Area is the Salt Valley anticline. Erosion resulting from the Tertiary uplift of the Colorado Plateau led to salt dissolution and subsequent collapse along the crest of the anticline. Continued erosion removed the collapse material, forming an axial valley along the crest of the anticline. Paleozoic rocks beneath the salt bearing Paradox Formation consist of limestone, dolomite, sandstone, siltstone and shale. The salt beds of the Paradox Formation occur in distinct cycles separated by an interbed sequence of anhydrite, carbonate, and clastic rocks. The Paradox Formation is overlain by Pennsylvanian limestone; Permian sandstone; and Mesozoic sandstone, mudstone, conglomerate and shale. No earthquakes have been reported in the Area during the period of the historic record and contemporary seismicity appears to be diffusely distributed, of low level and small magnitude. The upper unit includes the Permian strata and upper Honaker Trail Formation. The current data base is insufficient to estimate ground-water flow rates and directions in this unit. The middle unit includes the evaporites in the Paradox Formation and no laterally extensive flow systems are apparent. The lower unit consists of the rocks below the Paradox Formation where permeabilities vary widely, and the apparent flow direction is toward the west. 108 refs., 39 figs., 9 tabs

  15. Controlling groundwater pumping online.

    Science.gov (United States)

    Zekri, Slim

    2009-08-01

    Groundwater over-pumping is a major problem in several countries around the globe. Since controlling groundwater pumping through water flow meters is hardly feasible, the surrogate is to control electricity usage. This paper presents a framework to restrict groundwater pumping by implementing an annual individual electricity quota without interfering with the electricity pricing policy. The system could be monitored online through prepaid electricity meters. This provides low transaction costs of individual monitoring of users compared to the prohibitive costs of water flow metering and monitoring. The public groundwater managers' intervention is thus required to determine the water and electricity quota and watch the electricity use online. The proposed framework opens the door to the establishment of formal groundwater markets among users at very low transaction costs. A cost-benefit analysis over a 25-year period is used to evaluate the cost of non-action and compare it to the prepaid electricity quota framework in the Batinah coastal area of Oman. Results show that the damage cost to the community, if no active policy is implemented, amounts to (-$288) million. On the other hand, the implementation of a prepaid electricity quota with an online management system would result in a net present benefit of $199 million.

  16. Y-12 Groundwater Protection Program Groundwater and Surface Water Sampling and Analysis Plan For Calendar Year 2009

    Energy Technology Data Exchange (ETDEWEB)

    Elvado Environmental LLC

    2008-12-01

    This plan provides a description of the groundwater and surface water quality monitoring activities planned for calendar year (CY) 2009 at the U.S. Department of Energy (DOE) Y-12 National Security Complex (Y-12) that will be managed by the Y-12 Groundwater Protection Program (GWPP). Groundwater and surface water monitoring performed by the GWPP during CY 2009 will be in accordance with DOE Order 540.1 requirements and the following goals: (1) to protect the worker, the public, and the environment; (2) to maintain surveillance of existing and potential groundwater contamination sources; (3) to provide for the early detection of groundwater contamination and determine the quality of groundwater and surface water where contaminants are most likely to migrate beyond the Oak Ridge Reservation property line; (4) to identify and characterize long-term trends in groundwater quality at Y-12; and (5) to provide data to support decisions concerning the management and protection of groundwater resources. Groundwater and surface water monitoring during CY 2009 will be performed primarily in three hydrogeologic regimes at Y-12: the Bear Creek Hydrogeologic Regime (Bear Creek Regime), the Upper East Fork Poplar Creek Hydrogeologic Regime (East Fork Regime), and the Chestnut Ridge Hydrogeologic Regime (Chestnut Ridge Regime). The Bear Creek and East Fork regimes are located in Bear Creek Valley, and the Chestnut Ridge Regime is located south of Y-12 (Figure A.1). Additional surface water monitoring will be performed north of Pine Ridge, along the boundary of the Oak Ridge Reservation. Modifications to the CY 2009 monitoring program may be necessary during implementation. Changes in programmatic requirements may alter the analytes specified for selected monitoring wells or may add or remove wells from the planned monitoring network. All modifications to the monitoring program will be approved by the Y-12 GWPP manager and documented as addenda to this sampling and analysis plan

  17. A ground-water sapping landscape in the Florida Panhandle

    Science.gov (United States)

    Schumm, S. A.; Boyd, K. F.; Wolff, C. G.; Spitz, W. J.

    1995-07-01

    Drainage networks that have formed by ground-water sapping are developed in the highly permeable sands of the Citronelle Formation in the Florida Panhandle. The valleys resemble those formed on Hawaii, the Colorado Plateau and on Mars, but they have developed without significant lithologic controls. Drainage patterns range from trellis to dentritic depending on the effect of beach ridges and relative relief. Many of the drainage networks are not fully developed, and the adjacent uplands have been modified by marine, aeolian, and to a limited extent fluvial processes. Extension of the networks appears to be episodic, as a result of fires, hurricanes, and human activities, which damage or destroy vegetation.

  18. Belgrade waterworks groundwater source

    International Nuclear Information System (INIS)

    Sotic, A.; Dasic, M.; Vukcevic, G.; Vasiljevic, Lj.; Nikolic, S.

    2002-01-01

    Paper deals with Belgrade Waterworks groundwater source, its characteristics, conception of protection programme, contaminations on source and with parameters of groundwater quality degradation. Groundwaters present natural heritage with their strategic and slow renewable natural resources attributes, and as such they require priority in protection. It is of greatest need that existing source is to be protected and used optimally for producing quality drinkable water. The concept of source protection programme should be based on regular water quality monitoring, identification of contaminators, defining areas of their influences on the source and their permanent control. However, in the last 10 years, but drastically in the last 3, because of the overall situation in the country, it is very characteristic downfall in volume of business, organisation and the level of supply of the technical equipment

  19. Basin F Subregional Groundwater Model

    National Research Council Canada - National Science Library

    Mazion, Edward

    2001-01-01

    The groundwater flow system at Rocky Mountain Arsenal (RMA) is complex. To evaluate proposed remedial alternatives, interaction of the local groundwater flow system with the present contamination control systems must be understood...

  20. Tehran Groundwater Chemical Pollution

    Directory of Open Access Journals (Sweden)

    M- Shariatpanahi

    1990-06-01

    Full Text Available Seventy eight wells water sample of Tehran plain were examined to determine r its groundwaters chemical pollution. Tehran s groundwaters are slightly acidic and their total dissolved solids are high and are in the hard water category."nThe nitrate concentration of wells water of west region is less than per¬missible level of W.H.O. standard, whereas, the nitrate concentration of some of the other regions wells exceed W.H.O. standard which is indication of pollution"nwith municipal wastewaters. The concentration of toxic elements Cr, Cd, As, Hg and"ni Pb of some of the west, east and south regions wells of Tehran is more than per¬missible level of W.H.O. standard, whereas, the concentration of Cu, Zn,Mn and detergents is below W.H.O. standard."n1"nIn general, the amount of dissolved materials of Tehran s groundwaters and also"ni the potential of their contamination with nitrate is increased as Tehran s ground-"nwaters move further to the south, and even though, Tehran s groundwaters contamination with toxic elements is limited to the industrial west district, industrial-residential east and south districts, but»with regard to the disposal methods of"nt municipal and industrial wastewaters, if Tehran s groundwaters pollution continues,"nlocal contamination of groundwaters is likely to spread. So that finally their quality changes in such a way that this water source may become unfit for most domestic, industrial and agricultural uses. This survey shows the necessity of collection and treatment of Tehran s wastewaters and Prevention of the disposal of untreated wastewaters into the environment.

  1. The Role of Subsurface Water in Carving Hesperian Amphitheater-Headed Valleys

    Science.gov (United States)

    Lapotre, M. G. A.; Lamb, M. P.

    2017-12-01

    Groundwater sapping may play a role in valley formation in rare cases on Earth, typically in sand or weakly cemented sandstones. Small-scale valleys resulting from groundwater seepage in loose sand typically have amphitheater-shaped canyon heads with roughly uniform widths. By analogy to terrestrial sapping valleys, Hesperian-aged amphitheater canyons on Mars have been interpreted to result from groundwater sapping, with implications for subsurface and surface water flows on ancient Mars. However, other studies suggest that martian amphitheater canyons carved in fractured rock may instead result from large overland floods, by analogy to dry cataracts in scabland terrains in the northwestern U.S. Understanding the formation of bedrock canyons is critical to our understanding of liquid water reservoirs on ancient Mars. Can groundwater sapping carve canyons in substrates other than sand? There is currently no model to predict the necessary conditions for groundwater to carve canyons in substrates ranging from loose sediment of various sizes to competent rock. To bridge this knowledge gap, we formulate a theoretical model coupling equations of groundwater flow and sediment transport that can be applied to a wide range of substrates. The model is used to infer whether groundwater sapping could have carved canyons in the absence of overland flows, and requires limited inputs that are measureable in the field or from orbital images. Model results show that sapping erosion is capable of forming canyons, but only in loose well-sorted sand. Coarser sediment is more permeable, but more difficult to transport. Finer sediment is more easily transported, but lower permeability precludes the necessary seepage discharge. Finally, fractured rock is highly permeable, but seepage discharges are far below those required to transport typical talus boulders. Using orbiter-based lithological constraints, we conclude that canyons near Echus Chasma are carved into bedrock and therefore

  2. Technical framework for groundwater restoration

    International Nuclear Information System (INIS)

    1991-04-01

    This document provides the technical framework for groundwater restoration under Phase II of the Uranium Mill Tailings Remedial Action (UMTRA) Project. A preliminary management plan for Phase II has been set forth in a companion document titled ''Preplanning Guidance Document for Groundwater Restoration''. General principles of site characterization for groundwater restoration, restoration methods, and treatment are discussed in this document to provide an overview of standard technical approaches to groundwater restoration

  3. Visualization of groundwater withdrawals

    Science.gov (United States)

    Winston, Richard B.; Goode, Daniel J.

    2017-12-21

    Generating an informative display of groundwater withdrawals can sometimes be difficult because the symbols for closely spaced wells can overlap. An alternative method for displaying groundwater withdrawals is to generate a “footprint” of the withdrawals. WellFootprint version 1.0 implements the Footprint algorithm with two optional variations that can speed up the footprint calculation. ModelMuse has been modified in order to generate the input for WellFootprint and to read and graphically display the output from WellFootprint.

  4. Subpermafrost groundwater systems

    Science.gov (United States)

    van der Ploeg, Martine; Bense, Victor; Haldorsen, Sylvi

    2017-04-01

    Groundwater basins in polar areas are probably among the least studied systems in the World. Foremost, this is because such systems are mainly situated in sparsely populated areas. Also, where the permafrost is thick and continuous over large areas, the recharge is very limited and terrestrial discharge takes place only in some few springs. A now completed study of polar groundwater was carried out in Svalbard, the arctic archipelago north of Norway. Based on field observations and simulation models it was concluded that major discharge conduits only formed during extensive global glacial phases, beneath the parts of the glaciers were the ice was temperate. During most of the interglacial periods, when the glaciers retreat, the number of discharge springs will decrease gradually as long as continuous permafrost covers the area. However, the amount of recharge and thereby discharge in each individual groundwater spring is today highly dependent on short-time fluctuations in precipitation and air temperature. This situation may also be applicable in other polar areas where glaciers are abundant and parts of them are temperate. Such conditions occur in e.g. Greenland and on islands north of the North American mainland, as well as in parts of Antarctica. However, we cannot use the glacial-interglacial boundary conditions in all polar regions. Subpermafrost groundwater systems also exist in permafrost areas where few or no glaciers occur today and where the recharge has taken and takes place under e.g. larger lakes or snowfields. In many areas the groundwater systems may be much older than assumed in Svalbard. Their cycles may relate to several glaciations or to true non-glacial periods in the past. The development and melting of thick continuous permafrost are slow processes and the dynamic of the related groundwater systems will be dependent on cold/mild climate episodes lasting for many thousand years. The polar systems thereby have many of the same characteristics

  5. In situ groundwater bioremediation

    Energy Technology Data Exchange (ETDEWEB)

    Hazen, Terry C.

    2009-02-01

    In situ groundwater bioremediation of hydrocarbons has been used for more than 40 years. Most strategies involve biostimulation; however, recently bioaugmentation have been used for dehalorespiration. Aquifer and contaminant profiles are critical to determining the feasibility and strategy for in situ groundwater bioremediation. Hydraulic conductivity and redox conditions, including concentrations of terminal electron acceptors are critical to determine the feasibility and strategy for potential bioremediation applications. Conceptual models followed by characterization and subsequent numerical models are critical for efficient and cost effective bioremediation. Critical research needs in this area include better modeling and integration of remediation strategies with natural attenuation.

  6. Hydrological Modelling the Middle Magdalena Valley (Colombia)

    Science.gov (United States)

    Arenas, M. C.; Duque, N.; Arboleda, P.; Guadagnini, A.; Riva, M.; Donado-Garzon, L. D.

    2017-12-01

    Hydrological distributed modeling is key point for a comprehensive assessment of the feedback between the dynamics of the hydrological cycle, climate conditions and land use. Such modeling results are markedly relevant in the fields of water resources management, natural hazards and oil and gas industry. Here, we employ TopModel (TOPography based hydrological MODEL) for the hydrological modeling of an area in the Middle Magdalena Valley (MMV), a tropical basin located in Colombia. This study is located over the intertropical convergence zone and is characterized by special meteorological conditions, with fast water fluxes over the year. It has been subject to significant land use changes, as a result of intense economical activities, i.e., and agriculture, energy and oil & gas production. The model employees a record of 12 years of daily precipitation and evapotranspiration data as inputs. Streamflow data monitored across the same time frame are used for model calibration. The latter is performed by considering data from 2000 to 2008. Model validation then relies on observations from 2009 to 2012. The robustness of our analyses is based on the Nash-Sutcliffe coefficient (values of this metric being 0.62 and 0.53, respectively for model calibration and validation). Our results reveal high water storage capacity in the soil, and a marked subsurface runoff, consistent with the characteristics of the soil types in the regions. A significant influence on runoff response of the basin to topographical factors represented in the model is evidenced. Our calibrated model provides relevant indications about recharge in the region, which is important to quantify the interaction between surface water and groundwater, specially during the dry season, which is more relevant in climate-change and climate-variability scenarios.

  7. Potential Antifreeze Compounds in Present-Day Martian Seepage Groundwater

    Directory of Open Access Journals (Sweden)

    Jiin-Shuh Jean

    2008-01-01

    Full Text Available Is the recently found seepage groundwater on Mars pure H2O, or mixed with salts and other antifreeze compounds? Given the surface conditions of Mars, it is unlikely that pure water could either exist in its liquid state or have shaped Mars¡¦ fluid erosional landforms (gullies, channels, and valley networks. More likely is that Mars¡¦ seepage groundwater contains antifreeze and salt compounds that resist freezing and suppress evaporation. This model better accounts for Mars¡¦ enigmatic surface erosion. This paper suggests 17 antifreeze compounds potentially present in Martian seepage groundwater. Given their liquid state and physical properties, triethylene glycol, diethylene glycol, ethylene glycol, and 1,3-propylene glycol are advanced as the most likely candidate compounds. This paper also explores how a mixing of glycol or glycerol with salts in the Martian seepage groundwater may have lowered water¡¦s freezing point and raised its boiling point, with consequences that created fluid gully and channel erosion. Ethylene glycol and related hydrocarbon compounds have been identified in Martian and other interstellar meteorites. We suggest that these compounds and their proportions to water be included for detection in future explorations.

  8. Groundwater: A Community Action Guide.

    Science.gov (United States)

    Boyd, Susan, Ed.; And Others

    Designed to be a guide for community action, this booklet examines issues and trends related to groundwater contamination. Basic concepts about groundwater and information about problems affecting it are covered under the categories of (1) what is groundwater? (2) availability and depletion; (3) quality and contamination; (4) public health…

  9. Water ages of 20 groundwater bodies and its relevance for the implementation of the European Water Framework Directive

    Science.gov (United States)

    Kralik, Martin; Brielmann, Heike; Humer, Franko; Grath, Johannes; Sültenfuß, Jürgen; Philippitsch, Rudolf

    2015-04-01

    The 'Mean Residence Time' (MRT) of groundwater is required to develop reliable hydrogeological concepts of groundwater bodies as a prerequisite for a qualified monitoring and risk assessment. MRTs from monitoring wells help to assess if groundwater bodies are 'at risk' or 'not at risk' failing to meet good groundwater quantitative and chemical status according to the Water Framework Directive and therefore not being able to use the groundwater as drinking water or industrial water resource. A combination of 18O/2H, 3H, 3H/3He and in some cases additional CFC, SF6, 85Kr and 35S measurements allow to calculate reliable MRTs in 20 groundwater bodies covering 13% (approx.10719 km2) of the Austrian territory. Altogether 401 groundwater wells and springs from the existing groundwater monitoring network were analysed for δ18O (n=1500), 3H (n=800) and 3He (n=327) since 2006. Considering both the fact that monitoring wells may have multiple or long well screens and the inherent uncertainties of groundwater age dating techniques, age estimations were classified into 5 categories of short ( 50years) mean residence times for each monitoring site. Subsequently, median values of the MRT categories were assigned to each investigated groundwater body. These are valuable information to fix extraction rates, to set measures to improve the land use and groundwater protection and to validate hydrogeological concepts. Generally, MRTs of groundwater bodies increase from shallow Alpine groundwater bodies over deeper Alpine valley-aquifers to longer MRTs in the Pannonian climate range in the east of Austria.

  10. Calendar year 1995 groundwater quality report for the Bear Creek Hydrogeologic Regime, Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-02-01

    This annual groundwater quality report (GWQR) contains groundwater and surface water quality data obtained during the 1995 calendar year (CY) at several hazardous and nonhazardous waste management facilities associated with the Y-12 Plant located on the DOE Oak Ridge Reservation (ORR) southeast of Oak Ridge, Tennessee. The sites addressed by this document are located in Bear Creek Valley (BCV) west of the Y-12 Plant complex within the Bear Creek Hydrogeologic Regime. The Bear Creek Regime is one of three hydrogeologic regimes defined for the purposes of groundwater and surface water quality monitoring at the Y-12 Plant. The purpose of the Groundwater Protection Program (GWPP) is to characterize the hydrogeology and to monitor groundwater quality at the Y-12 Plant and surrounding area to provide for protection of groundwater resources consistent with federal, state, and local requirements. Part 1 (this report) consists primarily of data appendices and serves as a reference for the groundwater quality data obtained each CY under the lead of the Y-12 Plant GWPP. Part 2 of the report, to be issued mid-year, will contain an evaluation of the data with respect to regime-wide groundwater quality, present the findings and status of ongoing hydrogeologic studies, describe changes in monitoring priorities, and present planned modifications to the groundwater sampling and analysis program for the following CY.

  11. Calendar year 1995 groundwater quality report for the Beak Creek Hydrogeologic Regime, Y-12 Plant, Oak Ridge, Tennessee. Part 2: 1995 groundwater quality data interpretations

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-08-01

    This annual groundwater quality report (GWQR) contains an evaluation of the groundwater and surface water monitoring data obtained during the 1995 calendar year (CY) for several hazardous and nonhazardous waste management facilities associated with the US DOE Y-12 Plant. The sites addressed by this document are located in Bear Creek Valley (BCV) west of the Y-12 Plant complex within the Bear Creek Hydrogeologic Regime. The Bear Creek Regime is one of three hydrogeologic regimes defined for the purposes of groundwater and surface water quality monitoring at the Y-12 Plant. The purpose of the GWPP is to characterize the hydrogeology and to monitor groundwater quality at the Y-12 Plant and surrounding area to provide for protection of groundwater resources consistent with federal, state, and local requirements. Each annual Part 2 GWQR addresses RCRA interim status reporting requirements regarding assessment of the horizontal and vertical extent of groundwater contamination. This report includes background information regarding the extent of groundwater and surface water contamination in the Bear Creek Regime based on the conceptual models described in the remedial investigation report (Section 2); a summary of the groundwater and surface water monitoring activities performed during CY 1995 (Section 3.0); analysis and interpretation of the CY 1995 monitoring data for groundwater (Section 4.0) and surface water (Section 5.0); a summary of conclusions and recommendations (Section 6.0); and a list of cited references (Section 7.0). Appendices contain diagrams, graphs, data tables, and summaries and the evaluation and decision criteria for data screening.

  12. Predicted pH at the domestic and public supply drinking water depths, Central Valley, California

    Science.gov (United States)

    Rosecrans, Celia Z.; Nolan, Bernard T.; Gronberg, Jo Ann M.

    2017-03-08

    This scientific investigations map is a product of the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) project modeling and mapping team. The prediction grids depicted in this map are of continuous pH and are intended to provide an understanding of groundwater-quality conditions at the domestic and public supply drinking water zones in the groundwater of the Central Valley of California. The chemical quality of groundwater and the fate of many contaminants is often influenced by pH in all aquifers. These grids are of interest to water-resource managers, water-quality researchers, and groundwater modelers concerned with the occurrence of natural and anthropogenic contaminants related to pH. In this work, the median well depth categorized as domestic supply was 30 meters below land surface, and the median well depth categorized as public supply is 100 meters below land surface. Prediction grids were created using prediction modeling methods, specifically boosted regression trees (BRT) with a Gaussian error distribution within a statistical learning framework within the computing framework of R (http://www.r-project.org/). The statistical learning framework seeks to maximize the predictive performance of machine learning methods through model tuning by cross validation. The response variable was measured pH from 1,337 wells and was compiled from two sources: USGS National Water Information System (NWIS) database (all data are publicly available from the USGS: http://waterdata.usgs.gov/ca/nwis/nwis) and the California State Water Resources Control Board Division of Drinking Water (SWRCB-DDW) database (water quality data are publicly available from the SWRCB: http://www.waterboards.ca.gov/gama/geotracker_gama.shtml). Only wells with measured pH and well depth data were selected, and for wells with multiple records, only the most recent sample in the period 1993–2014 was used. A total of 1,003 wells (training dataset) were used to train the BRT

  13. CHARACTERIZATION OF GROUNDWATER HYDROCHEMISTRY ...

    African Journals Online (AJOL)

    Osondu

    2013-03-01

    Mar 1, 2013 ... The residual sodium carbonate shows that 18.2%, 13.6% and 15.9% of the samples are suitable, marginal and unsuitable water respectively ... groundwater in the host rock, the ambient temperature and pH, chemical ..... lagoon and the transitional effects on the lacustrine ichthyofaunal diversity. African J. of ...

  14. Mapping Aquifer Systems with Airborne Electromagnetics in the Central Valley of California

    Science.gov (United States)

    Knight, R. J.; Smith, R.; Asch, T. H.; Abraham, J.; Cannia, J.; Fogg, G. E.; Viezzoli, A.

    2016-12-01

    The Central Valley of California is an important agricultural region struggling to meet the need for irrigation water. Recent periods of drought have significantly reduced the delivery of surface water, resulting in extensive pumping of groundwater. This has exacerbated an already serious problem in the Central Valley, where a number of areas have experienced declining water levels for several decades leading to ongoing concerns about depletion of aquifers and impacts on ecosystems, as well as subsidence of the ground surface. The overdraft has been so significant, that there are now approximately140 million acre-feet (MAF) of unused groundwater storage in the Central Valley, storage that could be used to complement the 42 MAF of surface storage. The alluvial sedimentary geology of the Central Valley is typically composed of more than 50 to 70 percent fine-grained deposits dominated by silt and clay beds. These fine grained deposits can block potential recharge, and are associated with the large amount of observed subsidence. Fortunately, the geologic processes that formed the region created networks of sand and gravel which provide both a supply of water and pathways for recharge from the surface to the aquifers. The challenge is to find these sand and gravel deposits and thus identify optimal locations for surface spreading techniques so that recharge could be dramatically increased, and re-pressurization of the confined aquifer networks could be accomplished. We have acquired 100 line kilometers of airborne electromagnetic data over an area in the San Joaquin Valley, imaging the subsurface hydrostratigraphy to a depth of 500 m with spatial resolution on the order of meters to tens of meters. Following inversion of the data to obtain resistivity models along the flight lines, we used lithology logs in the area to transform the models to images displaying the distribution of sand and gravel, clay, and mixed fine and coarse materials. The quality of the data and

  15. Groundwater quota versus tiered groundwater pricing : two cases of groundwater management in north-west China

    NARCIS (Netherlands)

    Aarnoudse, Eefje; Qu, Wei; Bluemling, B.; Herzfeld, Thomas

    2017-01-01

    Difficulties in monitoring groundwater extraction cause groundwater regulations to fail worldwide. In two counties in north-west China local water authorities have installed smart card machines to monitor and regulate farmers’ groundwater use. Data from a household survey and in-depth interviews are

  16. HANFORD GROUNDWATER REMEDIATION

    Energy Technology Data Exchange (ETDEWEB)

    CHARBONEAU, B; THOMPSON, M; WILDE, R.; FORD, B.; GERBER, M.S.

    2006-02-01

    By 1990 nearly 50 years of producing plutonium put approximately 1.70E + 12 liters (450 billion gallons) of liquid wastes into the soil of the 1,518-square kilometer (586-square mile) Hanford Site in southeast Washington State. The liquid releases consisted of chemicals used in laboratory experiments, manufacturing and rinsing uranium fuel, dissolving that fuel after irradiation in Hanford's nuclear reactors, and in liquefying plutonium scraps needed to feed other plutonium-processing operations. Chemicals were also added to the water used to cool Hanford's reactors to prevent corrosion in the reactor tubes. In addition, water and acid rinses were used to clean plutonium deposits from piping in Hanford's large radiochemical facilities. All of these chemicals became contaminated with radionuclides. As Hanford raced to help win World War II, and then raced to produce materials for the Cold War, these radioactive liquid wastes were released to the Site's sandy soils. Early scientific experiments seemed to show that the most highly radioactive components of these liquids would bind to the soil just below the surface of the land, thus posing no threat to groundwater. Other experiments predicted that the water containing most radionuclides would take hundreds of years to seep into groundwater, decaying (or losing) most of its radioactivity before reaching the groundwater or subsequently flowing into the Columbia River, although it was known that some contaminants like tritium would move quickly. Evidence today, however, shows that many contaminants have reached the Site's groundwater and the Columbia River, with more on its way. Over 259 square kilometers (100 square miles) of groundwater at Hanford have contaminant levels above drinking-water standards. Also key to successfully cleaning up the Site is providing information resources and public-involvement opportunities to Hanford's stakeholders. This large, passionate, diverse, and

  17. Validation Analysis of the Shoal Groundwater Flow and Transport Model

    Energy Technology Data Exchange (ETDEWEB)

    A. Hassan; J. Chapman

    2008-11-01

    Environmental restoration at the Shoal underground nuclear test is following a process prescribed by a Federal Facility Agreement and Consent Order (FFACO) between the U.S. Department of Energy, the U.S. Department of Defense, and the State of Nevada. Characterization of the site included two stages of well drilling and testing in 1996 and 1999, and development and revision of numerical models of groundwater flow and radionuclide transport. Agreement on a contaminant boundary for the site and a corrective action plan was reached in 2006. Later that same year, three wells were installed for the purposes of model validation and site monitoring. The FFACO prescribes a five-year proof-of-concept period for demonstrating that the site groundwater model is capable of producing meaningful results with an acceptable level of uncertainty. The corrective action plan specifies a rigorous seven step validation process. The accepted groundwater model is evaluated using that process in light of the newly acquired data. The conceptual model of ground water flow for the Project Shoal Area considers groundwater flow through the fractured granite aquifer comprising the Sand Springs Range. Water enters the system by the infiltration of precipitation directly on the surface of the mountain range. Groundwater leaves the granite aquifer by flowing into alluvial deposits in the adjacent basins of Fourmile Flat and Fairview Valley. A groundwater divide is interpreted as coinciding with the western portion of the Sand Springs Range, west of the underground nuclear test, preventing flow from the test into Fourmile Flat. A very low conductivity shear zone east of the nuclear test roughly parallels the divide. The presence of these lateral boundaries, coupled with a regional discharge area to the northeast, is interpreted in the model as causing groundwater from the site to flow in a northeastward direction into Fairview Valley. Steady-state flow conditions are assumed given the absence of

  18. Ground-water contamination near a uranium tailings disposal site in Colorado

    International Nuclear Information System (INIS)

    Goode, D.J.; Wilder, R.J.

    1987-01-01

    Contaminants from uranium tailings disposed of at an active mill in Colorado have seeped into the shallow ground water onsite. This ground water discharges into the Arkansas River Valley through a superposed stream channel cut in the resistant sandstone ridge at the edge of a synclinal basin. In the river valley, seasonal surface-water irrigation has a significant impact on hydrodynamics. Water levels in residential wells fluctuate up to 20 ft and concentrations of uranium, molybdenum, and other contaminants also vary seasonally, with highest concentrations in the Spring, prior to irrigation, and lowest concentrations in the Fall. Results of a simple transient mixing cell model support the hypothesis that lateral ground-water inflow, and not irrigation recharge, is the source of ground-water contamination

  19. Assessment of groundwater vulnerability in the Río Artiguas basin, Nicaragua

    Science.gov (United States)

    Mendoza, J. A.; Barmen, G.

    2006-07-01

    The Río Artiguas basin in central Nicaragua shows a distinctive case of environmental deterioration due to anthropogenic activities. Heavy metals used in gold mining and other wastes are continuously released into the rivers, representing a threat to the water quality. This article aims to evaluate the groundwater intrinsic vulnerability in the Río Artiguas basin and to provide information for sustainable use of water resources. The DRASTIC and GOD methods were used to analyse the relative pollution potential within the basin. DRASTIC was modified to include the degree of influence that geological structures have on the vulnerability. Moderate vulnerability areas cover most of the basin along stream valleys and lowlands, increasing downstream in the basin. The resulting vulnerability maps show that the limited groundwater resources are susceptible to surface water pollution as high vulnerability areas converge along the river valleys.

  20. Hydrogeological and groundwater modeling studies to estimate the groundwater inflows into the coal Mines at different mine development stages using MODFLOW, Andhra Pradesh, India

    Directory of Open Access Journals (Sweden)

    L. Surinaidu

    2014-09-01

    Full Text Available The Singareni Collieries Company Ltd (SCCL is exploiting coal in the Godavari valley coal fields spread over 5.33 km2 in Andhra Pradesh, India. In the area, six workable coal seams have been identified in Barakar formation by the analysis of the geologic logs of 183 bore wells. A finite difference based numerical groundwater flow model is developed with twenty conceptual layers and with a total thickness of 320 m. The flow model was calibrated under steady state conditions and predicted groundwater inflows into the mine pits at different mine development stages. The groundwater budget results revealed that the mining area would receive net groundwater inflows of 5877 m3 day−1, 12,818 m3 day−1, 12,910 m3 day−1, 20,428 m3 day−1, 22,617 m3 day−1 and 14,504 m3 day−1 at six mine development stages of +124 m (amsl, +93 m (amsl, +64 m (amsl, +41 m (amsl, +0 m (amsl and −41 m (amsl, respectively. The results of the study can be used to plan optimal groundwater pumping and the possible locations to dewater the groundwater for safe mining at different mine development stages.

  1. Integrated hydrologic model of Pajaro Valley, Santa Cruz and Monterey Counties, California

    Science.gov (United States)

    Hanson, Randall T.; Schmid, Wolfgang; Faunt, Claudia C.; Lear, Jonathan; Lockwood, Brian

    2014-01-01

    Increasing population, agricultural development (including shifts to more water-intensive crops), and climate variability are placing increasingly larger demands on available groundwater resources in the Pajaro Valley, one of the most productive agricultural regions in the world. This study provided a refined conceptual model, geohydrologic framework, and integrated hydrologic model of the Pajaro Valley. The goal of this study was to produce a model capable of being accurate at scales relevant to water management decisions that are being considered in the revision and updates to the Basin Management Plan (BMP). The Pajaro Valley Hydrologic Model (PVHM) was designed to reproduce the most important natural and human components of the hydrologic system and related climatic factors, permitting an accurate assessment of groundwater conditions and processes that can inform the new BMP and help to improve planning for long-term sustainability of water resources. Model development included a revision of the conceptual model of the flow system, reevaluation of the previous model transformed into MODFLOW, implementation of the new geohydrologic model and conceptual model, and calibration of the transient hydrologic model.

  2. Groundwater Protection Program Calendar Year 1998 Groundwater Monitoring Report, U.S. Department of Energy Y-12 Plant, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    This annual monitoring report contains groundwater and surface water monitoring data obtained during calendar year (CY) 1998 by the Lockheed Martin Energy Systems, Inc. Y-12 Plant Groundwater Protection Program (GWPP) at the U.S. Department of Energy (DOE) Oak Ridge Y-12 Plant, Groundwater and surface water monitoring during CY 1998 was performed in three hydrogeologic regimes at the Y-12 Plant: the Bear Creek Hydrogeologic Regime (Bear Creek Regime), the Chestnut Ridge Hydrogeologic Regime (Chestnut Ridge Regime), and the Upper East Fork Poplar Creek Hydrogeologic Regime (East Fork Regime). The Bear Creek and East Fork regimes are located in Bear Creek Valley (BCV), and the Chestnut Ridge Regime which is located south of the Y-12 Plant.

  3. Groundwater Protection Program Cale