Science.gov

Sample records for hydrogeology

  1. Hydrogeology

    SciTech Connect

    Back, W.; Rosenshein, J.S.; Seaber, P.R.

    1988-01-01

    This book demonstrates hydrogeologic principles, concepts, and processes that control the occurrence, movement, storage, and chemical character of ground water. It aims to identify, clarify, and describe systematically the basic relation of hydrogeology to other disciplines of geology, such as geomorphology, stratigraphy, structure, and historical geology.

  2. Undergraduate Education in Hydrogeology.

    ERIC Educational Resources Information Center

    Tinker, John Richard, Jr.

    1989-01-01

    Discusses a course at the University of Wisconsin-Eau Claire which improved instruction in physical hydrogeology, chemical hydrogeology, and water resources. Describes 14 laboratory activities including objectives, methods, and a list of equipment needed. (Author/MVL)

  3. HYDROGEOLOGIC CASE STUDIES

    EPA Science Inventory

    Hydrogeology is the foundation of subsurface site characterization for evaluations of monitored natural attenuation (MNA). Three case studies are presented. Examples of the potentially detrimental effects of drilling additives on ground-water samples from monitoring wells are d...

  4. Education and Employment in Hydrogeology.

    ERIC Educational Resources Information Center

    Pederson, Darryll T.

    1987-01-01

    Reports on a study of position descriptions in the field of hydrogeology appearing in want ads, published studies describing the working professional, and published descriptions of hydrogeology programs. Results indicate an increase in positions of ten times that of five years ago. Suggests basic training requirements for beginning…

  5. HYDROGEOLOGIC CASE STUDIES (DENVER PRESENTATION)

    EPA Science Inventory

    Hydrogeology is the foundation of subsurface site characterization for evaluations of monitored natural attenuation (MNA). Three case studies are presented. Examples of the potentially detrimental effects of drilling additives on ground-water samples from monitoring wells are d...

  6. Hydrogeologic Case Studies (Seattle, WA)

    EPA Science Inventory

    Hydrogeology is the foundation of subsurface site characterization for evaluations of monitored natural attenuation (MNA). Three case studies are presented. Examples of the potentially detrimental effects of drilling additives on ground-water samples from monitoring wells are d...

  7. HYDROGEOLOGIC CASE STUDIES (CHICAGO, IL)

    EPA Science Inventory

    Hydrogeology is the foundation of subsurface site characterization for evaluations of monitored natural attenuation (MNA). Three case studies are presented. Examples of the potentially detrimental effects of drilling additives on ground-water samples from monitoring wells are d...

  8. Coral reef hydrogeology

    SciTech Connect

    Buddemeier, R.W.; Oberdorfer, J.A.

    1985-05-21

    Knowledge of internal flow velocities and pore water residence time is important in understanding pore water geochemistry, nutrient fluxes at the benthic boundary, reef diagenesis, and fresh water resources in reef islands. Hydrogeologic studies of Pacific and Indian Ocean reef and atoll islands indicate a dual aquifer systems; the major Pleistocene aquifer has hydraulic conductivities on the order of 1000 m/d, while the overlying Holocene aquifer of unconsolidated sediments is at least an order of magnitude less permeable. The high permeability in the Pleistocene formation is the result of large voids, both constructional and from subaerial solution during low stands of the sea. Wind, wave and tide induced head differences ranging from a few centimeters to several tens of centimeters provide the driving force for internal flow. Pore water residence times and geochemistry will vary greatly, depending on whether the water is in a major flow channel or in more restricted pores. Studies of both submerged reefs and atoll islands give bulk pore water residence times on the order of months to a few years. Chemical analyses of pore water indicate that both carbonate solution and precipitation are taking place, which will alter porosity and permeability with time. The dual aquifer model also suggests that the Ghyben-Herzberg lens approach to reef island fresh water resources is inaccurate and can lead to a gross overestimation of the potable resource. 18 refs., 5 figs.

  9. Hydrogeology of sedimentary basins

    NASA Astrophysics Data System (ADS)

    Kreitler, Charles W.

    1989-03-01

    Hydrogeologic environments in sedimentary basins are as variable as are the different types of basins. Important hydrologic characteristics can be used to distinguish the different types of basin: (1) the topographic setting as determined by the geologic and structural history of the basin; (2) permeability distribution within the basin; and (3) potential energy distributions and flow mechanisms. These parameters control residence times of waters, rates and directions of saline groundwater flow and the origin and chemical composition of the saline waters. The Gulf Coast and Palo Duro Basins, Texas, exemplify two end member types of sedimentary basins. The Gulf Coast Basin is a relatively young, Tertiary-age basin which is presently compacting; fluid movement is from the overpressured, undercompacted sediments up the structural dip or up fault zones into the hydrostatic section, natural fluid pressures are either hydrostatic or overpressured. The Palo Duro is an older, Paleozoic-age basin that has been tectonically uplifted. Fluid flow is gravity driven from topographically high recharge areas to discharge in topographically low areas. Fluid pressures are subhydrostatic. Fluids discharge more easily than they are recharged. Not all flow is derived by a simple recharge discharge model. Brines may flow from other basins into the Palo Duro Basin and waters may discharge from the Palo Duro Basin into other basins. Areal differences in the chemical composition of the basin brines may be the result of different origins.

  10. SRS Geology/Hydrogeology Environmental Information Document

    SciTech Connect

    Denham, M.E.

    1999-08-31

    The purpose of the Savannah River Site Geology and Hydrogeology Environmental Information Document (EID) is to provide geologic and hydrogeologic information to serve as a baseline to evaluate potential environmental impacts. This EID is based on a summary of knowledge accumulated from research conducted at the Savannah River Site (SRS) and surrounding areas.

  11. Advanced Borehole Radar for Hydrogeology

    NASA Astrophysics Data System (ADS)

    Sato, M.

    2014-12-01

    Ground Penetrating Radar is a useful tool for monitoring the hydrogeological environment. We have developed GPR systems which can be applied to these purposes, and we will demonstrate examples borehole radar measurements. In order to have longer radar detection range, frequency lower than100MHz has been normally adopted in borehole radar. Typical subsurface fractures of our interests have a few mm aperture and radar resolution is much poorer than a few cm in this frequency range. We are proposing and demonstrating to use radar polarimetry to solve this problem. We have demonstrated that a full-polarimetry borehole radar can be used for characterization of subsurface fractures. Together with signal processing for antenna characteristic compensation to equalize the signal by a dipole antenna and slot antennas, we could demonstrate that polarimetric borehole radar can estimate the surface roughness of subsurface fractures, We believe the surface roughness is closely related to water permeability through the fractures. We then developed a directional borehole radar, which uses optical field sensor. A dipole antenna in a borehole has omni-directional radiation pattern, and we cannot get azimuthal information about the scatterers. We use multiple dipole antennas set around the borehole axis, and from the phase differences, we can estimate the 3-diemnational orientation of subsurface structures. We are using optical electric field sensor for receiver of borehole radar. This is a passive sensor and connected only with optical fibers and does not require any electric power supply to operate the receiver. It has two major advantages; the first one is that the receiver can be electrically isolated from other parts, and wave coupling to a logging cable is avoided. Then, secondary, it can operate for a long time, because it does not require battery installed inside the system. It makes it possible to set sensors in fixed positions to monitor the change of environmental conditions for a long period. We demonstrated this idea using cross- hole borehole radar measurement. We think this method is useful for detecting any changes in hydrogeological situations, which will be useful for subsurface storage such as LNG and nuclear waste.

  12. SRP Baseline Hydrogeologic Investigation, Phase 3

    SciTech Connect

    Bledsoe, H.W.

    1988-08-01

    The SRP Baseline Hydrogeologic Investigation was implemented for the purpose of updating and improving the knowledge and understanding of the hydrogeologic systems underlying the SRP site. Phase III, which is discussed in this report, includes the drilling of 7 deep coreholes (sites P-24 through P-30) and the installation of 53 observation wells ranging in depth from approximately 50 ft to more than 970 ft below the ground surface. In addition to the collection of geologic cores for lithologic and stratigraphic study, samples were also collected for the determination of physical characteristics of the sediments and for the identification of microorganisms.

  13. SRP baseline hydrogeologic investigation, Phase 2

    SciTech Connect

    Bledsoe, H.W.

    1987-11-01

    As discussed in the program plan for the Savannah River Plant (SRP) Baseline Hydrogeologic Investigation, this program has been implemented for the purpose of updating and improving the current state of knowledge and understanding of the hydrogeologic systems underlying the Savannah River Plant (SRP). The objective of the program is to install a series of observation well clusters (wells installed in each major water bearing formation at the same site) at key locations across the plant site in order to: (1) provide detailed information on the lithology, stratigraphy, and groundwater hydrology, (2) provide observation wells to monitor the groundwater quality, head relationships, gradients, and flow paths.

  14. Small Scale Multisource Site – Hydrogeology Investigation

    EPA Science Inventory

    A site impacted by brackish water was evaluated using traditional hydrogeologic and geochemical site characterization techniques. No single, specific source of the brine impacted ground water was identified. However, the extent of the brine impacted ground water was found to be...

  15. Hydrogeology of the West Siberian Basin

    SciTech Connect

    Foley, M.G.; Bradley, D.J.; Cole, C.R.

    1996-08-01

    Nuclear fuel cycle activities of the former Soviet Union (FSU) have resulted in extensive radioactive contaminant releases to the environment in western Siberia. We are developing three-dimensional numerical models of the hydrogeology and potential contaminant migration in the West Siberian Basin. We have assumed that ground-water flow in the West Siberian Basin is topographically driven, with recharge to the basin occurring in the highlands on the west, east, and south, and internal discharge localized in numerous river valleys and lakes that ultimately discharge north to the ocean. We are modeling the regional hydrogeology as three-dimensional, steady-state, saturated flow that is recharged from above. We acquired topographic, geologic, hydrostratigraphic, hydrogeologic, and water-balance data for the West Siberian Basin and constructed a regional water table. We correlated and combined 70 different rock types derived from published descriptions of West Siberian Basin rocks into 17 rock types appropriate for assignment of hydrogeologic properties on the basis of spatial heterogeneity and constituent (i.e., sand, silt, and clay) diversity. Examination of resulting three-dimensional assemblages of rock types showed that they were consistent with published and inferred paleogeography and depositional processes. Calibrating the basin`s moisture balance (i.e., recharge and discharge) to the derived water table determined plausible input parameter values for unknowns such as hydraulic conductivities. The general directions of calculated ground-water flow suggest that major rivers act as discharge areas, with upwelling below the rivers extending down into the basement rocks, and that ground-water divides that penetrate the entire thickness of the model are evident between major rivers.

  16. Hydrogeology, waste disposal, science and politics: Proceedings

    SciTech Connect

    Link, P.K.

    1994-07-01

    A total of 48 papers were presented at the Engineering Geology and Geotechnical Engineering 30th Symposium. These papers are presented in this proceedings under the following headings: site characterization--Pocatello area; site characterization--Boise Area; site assessment; Idaho National Engineering Laboratory; geophysical methods; remediation; geotechnical engineering; and hydrogeology, northern and western Idaho. Individual papers have been processed separately for inclusion in the Energy Science and Technology Database.

  17. Data-domain correlation approach for joint hydrogeologic inversion of time-lapse hydrogeologic and geophysical data

    SciTech Connect

    Timothy C. Johnson; Roelof J. Versteeg; Hai Huang; Partha S. Routh

    2009-11-01

    Inverse estimations of hydrogeologic properties are often highly uncertain due to the expense of collecting hydrogeologic data and the subsequent lack of information. Geophysical data can potentially help fill this information gap because geophysical methods can survey large areas remotely and relatively inexpensively. However, geophysical data are difficult to incorporate into hydrogeological parameter estimations due primarily to a lack of knowledge concerning the petrophysical relationships between hydrogeological and geophysical parameters. We present a method which allows time lapse geophysical data to be directly incorporated into a hydrogeological parameter estimation when there is a strong correlation between changes in geophysical and hydrogeological properties. This approach bypasses the need for an explicit petrophysical transform by formulating the geophysical part of the hydrogeological inversion in terms of a data domain correlation operator. We demonstrate the approach with a synthetic electrical resistivity monitoring application used to estimate the hydraulic conductivity distribution. Including time lapse resistivity data to supplement sparse hydrological data appears to greatly improve resolution of hydraulic conductivity in this case. More generally, the formulation and results suggest that geophysical monitoring data can be effectively incorporated into a hydrogeological parameter estimation using a data domain correlation operator, assuming there is a strong correlation between changes in hydrogeological and geophysical properties.

  18. Marine hydrogeology: recent accomplishments and future opportunities

    NASA Astrophysics Data System (ADS)

    Fisher, A. T.

    2005-03-01

    Marine hydrogeology is a broad-ranging scientific discipline involving the exploration of fluid-rock interactions below the seafloor. Studies have been conducted at seafloor spreading centers, mid-plate locations, and in plate- and continental-margin environments. Although many seafloor locations are remote, there are aspects of marine systems that make them uniquely suited for hydrologic analysis. Newly developed tools and techniques, and the establishment of several multidisciplinary programs for oceanographic exploration, have helped to push marine hydrogeology forward over the last several decades. Most marine hydrogeologic work has focused on measurement or estimation of hydrogeologic properties within the shallow subsurface, but additional work has emphasized measurements of local and global fluxes, fluid source and sink terms, and quantitative links between hydrogeologic, chemical, tectonic, biological, and geophysical processes. In addition to summarizing selected results from a small number of case studies, this paper includes a description of several new experiments and programs that will provide outstanding opportunities to address fundamental hydrogeologic questions within the seafloor during the next 20-30 years. L'hydrogéologie marine est une large discipline scientifique impliquant l' exploration des interactions entre les fluides et les roches sous les fonds marins. Des études ont été menées dans les différents environnements sous-marins (zone abyssale, plaque océanique, marges continentales). Bien que de nombreux fonds marins soient connus, il existe des aspects des systèmes marins qui les rendent inadaptés à l'analyse hydrologique. De nouveaux outils et techniques, et la mise en oeuvre de nombreux programmes multidisciplinaires d'exploration océanographique, ont aidé à pousser en avant l'hydrogéologie marine ces dix dernières années. La plus part des études hydrogéologiques se sont concentrées jusqu'à présent sur la mesure ou l'estimation des propriétés à la sub-surface des fonds marins, et des travaux complémentaires ont mis en valeur les mesures de flux, local ou global, de termes « sources » et « pertes », et des liens quantitatifs entre l'hydrogéologie, la chimie, la tectonique, la biologie, et les processus géophysiques. Cet article vise à résumer des résultats sélectionnés parmi un petit nombre d'études, et à décrire plusieurs nouvelles expériences et programmes, qui sont autant d'opportunités pour répondre aux questions fondamentales relatives aux fonds marins, posées ces dernières 20-30 années. La hidrogeología marina es una disciplina científica de amplios alcances que involucra la exploración de interacciones fluido-roca por debajo del fondo del mar. Se han llevado a cabo estudios en centros de expansión del fondo del mar, lugares en medio de una placa, y en ambientes de placa y margen continental. Aunque muchos sitios en el fondo del mar son remotos, existen aspectos de estos sistemas marinos que los hacen particularmente adaptables para análisis hidrológico. Nuevas técnicas y herramientas desarrolladas, y el establecimiento de varios programas multidisciplinarios para exploración oceanográfica, han ayudado a impulsar la hidrogeología marina hacia delante durante las ultimas décadas. La mayor parte del trabajo hidrogeológico marino se ha enfocado en la medición o estimación de propiedades hidrogeológicas dentro del subsuelo superficial, pero trabajo adicionalha enfatizado mediciones de flujos globales y locales, términos de fuente y sumidero de fluidos, y vínculos cuantitativos entre procesos hidrogeológicos, químicos, tectónicos, biológicos y geofísicos. Además de resumir resultados seleccionados de un número pequeño de estudios de caso, este artículo incluye una descripción de varios programas y experimentos nuevos que aportarán oportunidades excepcionales para dirigir preguntas hidrogeológicas fundamentales dentro del fondo oceánico durante los siguientes 20-30 años.

  19. Two-hundred years of hydrogeology in the United States

    USGS Publications Warehouse

    Rosenshein, J. S., (Edited By); Moore, J.E.; Lohman, S.W.; Chase, E.B.

    1986-01-01

    The Hydrogeology Division of the Geological Society of America (GSA) sponsored a symposium entitled ' Hydrogeology in the United States, 1776- 1976 ' at the annual meeting of the GSA on November 9, 1976. The symposium was organized to provide a forum for discussion of major eras in the history of American hydrogeology and to contribute to the bicentennial celebration of the founding of the United States. Presentations were broken down into 3 sections: The Early Era (with a tribute to Oscar E. Meinzer), 1776-1920; Meinzer Era, 1910-1940; and the Modern Era (including scientific advantages; the quantification of hydrogeology; geochemistry; surface and borehole geophysics; and hydrogeology, policy, and politics) 1940-1976. (Lantz-PTT)

  20. Hydrogeological model of the Baltic Artesian Basin

    NASA Astrophysics Data System (ADS)

    Virbulis, Janis; Bethers, Uldis; Saks, Tomas; Sennikovs, Juris; Timuhins, Andrejs

    2013-06-01

    The Baltic Artesian Basin (BAB) is a complex multi-layered hydrogeological system in the south-eastern Baltic covering about 480,000 km2. The aim of this study is to develop a closed hydrogeological mathematical model for the BAB. Heterogeneous geological data from different sources were used to build the geometry of the model, i.e. geological maps and stratigraphic information from around 20,000 boreholes. The finite element method was used for the calculation of the steady-state three-dimensional (3D) flow of unconfined groundwater. The 24-layer model was divided into about 1,000,000 finite elements. A simple recharge model was applied to describe the rate of infiltration, and the discharge was set at the water-supply wells. Variable hydraulic conductivities were used for the upper (Quaternary) deposits, while constant hydraulic conductivity values were assumed for the deeper layers. The model was calibrated on the statistically weighted borehole water-level measurements, applying L-BFGS-B (automatic parameter optimization method) for the hydraulic conductivities of each layer. The principal flows inside the BAB and the integral flow parameters were analyzed. The modeling results suggest that deeper aquifers are characterized by strong southeast-northwest groundwater flow, which is altered by the local topography in the upper, active water-exchange aquifers.

  1. Hydrogeology in North America: past and future

    NASA Astrophysics Data System (ADS)

    Narasimhan, T. N.

    2005-03-01

    This paper is a retrospective on the evolution of hydrogeology in North America over the past two centuries, and a brief speculation of its future. The history of hydrogeology is marked by developments in many different fields such as groundwater hydrology, soil mechanics, soil science, economic geology, petroleum engineering, structural geology, geochemistry, geophysics, marine geology, and more recently, ecology. The field has been enriched by the contributions of distinguished researchers from all these fields. At present, hydrogeology is in transition from a state of discovering new resources and exploiting them efficiently for maximum benefit, to one of judicious management of finite, interconnected resources that are vital for the sustenance of humans and other living things. The future of hydrogeology is likely to be dictated by the subtle balance with which the hydrological, erosional, and nutritional cycles function, and the decision of a technological society to either adapt to the constraints imposed by the balance, or to continue to exploit hydrogeological systems for maximum benefit. Although there is now a trend towards ecological and environmental awareness, human attitudes could change should large parts of the populated world be subjected to the stresses of droughts that last for many decades. Cet article est une rétrospective de l'évolution de l'hydrogéologie en Amérique du Nord sur les deux derniers siècles, et une brève évaluation de son futur. L'histoire de l'hydrogéologie est marquée par le développement de plusieurs techniques de terrain telles, l'hydrologie des eaux souterraines, la mécanique des sols, les sciences du sol, la géologie économique, l' ingénierie pétrolière, la géologie structurale, la géochimie, la géophysique, la géologie marine et plus récemment l'écologie. La science a été enrichie par la contribution de plusieurs chercheurs distingués, provenant de toutes ces branches. A présent, l'hydrogéologie est à la transition entre la volonté de découvrir de nouvelles ressources et l' exploitation la plus bénéfique au possible, et un management judicieux des ressources finies, interconnectées, qui sont vitales pour l' approvisionnement des hommes et autres formes de vie. Le futur de l' hydrogéologie sera dicté par la balance subtile dans laquelle intervient les cycles de l'hydrologie, de l'érosion, de la nutrition, et la décision d'une société technologique qui s'adapterait aux contraintes de la balance, ou qui continuerait d'exploiter les systèmes hydrologiques pour un bénéfice maximum. Par ailleurs il y a une nette tendance à inclure les aspects écologiques, les aspects environnementaux, et les changements humains qui pourraient être influencés par les modifications hydrogéologiques observées depuis une dizaine d'années. Este articulo es una retrospectiva sobre la evolución de la hidrogeología en Norte América en los pasados dos siglos, y una breve especulación de su futuro. La historia de la hidrogeología está marcada por desarrollos en muchos campos diferentes tal como hidrología de aguas subterráneas, mecánica de suelos, ciencia del suelo, geología económica, ingeniería del petróleo, geología estructural, geoquímica, geofísica, geología marina, y más recientemente, ecología. El campo se ha enriquecido por las contribuciones de investigadores distinguidos en todos esos campos. Actualmente, la hidrogeología se encuentra en transición de un estado de descubrir nuevos recursos y explotarlos eficientemente para un beneficio máximo, a un estado de gestión juiciosa de recursos finitos, interconectados, que son vitales para el sustento de humanos y otras cosas vivientes. El futuro de la hidrogeología posiblemente esté determinado por el balance sutil con el cual funcionan los ciclos nutricionales, erosionales e hidrológicos, y la decisión de una sociedad tecnológica para ya sea adaptarse a las restricciones impuestas por el balance o para continuar con la explotación de los sistemas hidrogeológicos para un benefici

  2. Hydrogeological Conditions Changes of Tomsk, Russia

    NASA Astrophysics Data System (ADS)

    Pokrovsky, V. D.; Dutova, E. M.; Kuzevanov, K. I.; Pokrovsky, D. S.; Nalivaiko, N. G.

    2015-11-01

    The hydro-geological conditions of Tomsk are determined by both natural factors and the impact of the urban infrastructure. Important impact on subsurface water flows involves the complex hydraulic relationship of several geological layers and the ancient and modern relief. Increasing groundwater abstraction has generally led to lowered piezometric heads in the deeper aquifer horizons, while in the uppermost horizons, rises in the water table and formation of new perched water tables are experienced due to leaking pipes and impedance of groundwater flow by deep foundations. In this paper special attention is paid to the Quaternary aquifer complex. Barrage effects of pile foundations and the intensive development of perched water distributed on flat surfaces of the watersheds and high terraces, complicated conditions for the construction and operation of facilities, leading in some cases to emergency situations.

  3. Chemical hydrogeology in natural and contaminated environments

    USGS Publications Warehouse

    Back, W.; Baedecker, M.J.

    1989-01-01

    Chemical hydrogeology, including organic and inorganic aspects, has contributed to an increased understanding of groundwater flow systems, geologic processes, and stressed environments. Most of the basic principles of inorganic-chemical hydrogeology were first established by investigations of organic-free, regional-scale systems for which simplifying assumptions could be made. The problems of groundwater contamination are causing a shift of emphasis to microscale systems that are dominated by organic-chemical reactions and that are providing an impetus for the study of naturally occurring and manmade organic material. Along with the decrease in scale, physical and chemical heterogeneity become major controls. Current investigations and those selected from the literature demonstrate that heterogeneity increases in importance as the study site decreases from regional-scale to macroscale to microscale. Increased understanding of regional-scale flow systems is demonstrated by selection of investigations of carbonate and volcanic aquifers to show how applications of present-day concepts and techniques can identify controlling chemical reactions and determine their rates; identify groundwater flow paths and determine flow velocity; and determine aquifer characteristics. The role of chemical hydrogeology in understanding geologic processes of macroscale systems is exemplified by selection of investigations in coastal aquifers. Phenomena associated with the mixing zone generated by encroaching sea water include an increase in heterogeneity of permeability, diagenesis of minerals, and formation of geomorphic features, such as caves, lagoons, and bays. Ore deposits of manganese and uranium, along with a simulation model of ore-forming fluids, demonstrate the influence of heterogeneity and of organic compounds on geochemical reactions associated with genesis of mineral deposits. In microscale environments, importance of heterogeneity and consequences of organic reactions in determining the distribution and concentrations cf. constituents are provided by several studies, including infiltration of sewage effluent and migration of creosote in coastal plain aquifers. These studies show that heterogeneity and the dominance of organically controlled reactions greatly increase the complexity of investigations.Current investigations and those selected from the literature demonstrate that heterogeneity increases in importance as the study site decreases from regional-scale to macroscale to microscale. Increased understanding of regional-scale flow systems is demonstrated by selection of investigations of carbonate and volcanic aquifers to show how application of present-day concepts and techniques can identify controlling chemical reactions and determine their rates; identify groundwater flow paths and determine flow velocity; and determine aquifer characteristics. The role of chemical hydrogeology in understanding geologic processes of macroscale systems is exemplified by selection of investigations in coastal aquifers. Ore deposits of manganese and uranium, along with a simulation model of ore-forming fluids, demonstrate the influence of heterogeneity and of organic compounds on geochemical reactions associated with genesis of mineral deposits. In microscale environments, importance of heterogeneity is illustrated by studies of infiltration of sewage effluent and migration of creosote in coastal plain aquifers.

  4. Stochastic hydrogeologic units and hydrogeologic properties development for total-system performance assessments. Yucca Mountain Site Characterization Project

    SciTech Connect

    Schenker, A.R.; Guerin, D.C.; Robey, T.H.; Rautman, C.A.; Barnard, R.W.

    1995-09-01

    A stochastic representation of the lithologic units and associated hydrogeologic parameters of the potential high-level nuclear waste repository are developed for use in performance-assessment calculations, including the Total-System Performance Assessment for Yucca Mountain-SNL Second Iteration (TSPA-1993). A simplified lithologic model has been developed based on the physical characteristics of the welded and nonwelded units at Yucca Mountain. Ten hydrogeologic units are developed from site-specific data (lithologic and geophysical logs and core photographs) obtained from the unsaturated and saturated zones. The three-dimensional geostatistical model of the ten hydrogeologic units is based on indicator-coding techniques and improves on the two-dimensional model developed for TSPA91. The hydrogeologic properties (statistics and probability distribution functions) are developed from the results of laboratory tests and in-situ aquifer tests or are derived through fundamental relationships. Hydrogeologic properties for matrix properties, bulk conductivities, and fractures are developed from existing site specific data. Extensive data are available for matrix porosity, bulk density, and matrix saturated conductivity. For other hydrogeologic properties, the data are minimal or nonexistent. Parameters for the properties are developed as beta probability distribution functions. For the model units without enough data for analysis, parameters are developed as analogs to existing units. A relational, analytic approach coupled with bulk conductivity parameters is used to develop fracture parameters based on the smooth-wall-parallel-plate theory. An analytic method is introduced for scaling small-core matrix properties to the hydrogeologic unit scales.

  5. Hydrogeology of the West Siberian Basin

    SciTech Connect

    Hoover, K.A.; Foley, M.G.; Bradley, D.J.

    1996-12-31

    Nuclear fuel cycle activities of the former Soviet Union (FSU) have resulted in significant contamination of the environment in western Siberia. The radioactive releases to surface waters and the surficial environment from the Mayak site are the largest known in the world. However, they are dwarfed by the amounts of liquid wastes injected into the subsurface at Tomsk and Krasnoyarsk since the early 1960s. This paper provides the status of efforts by Pacific Northwest National Laboratory to quantify the regional hydrogeologic context for potential contaminant migration from areas in western Siberia. The West Siberian Basin is the largest platformal basin and region of low relief on earth. Ground water in the West Siberian Basin is contained in a single geologic structure (i.e., a single basin). Hydrogeologic cross sections indicate that freshwater wedges are present in both unconfined and confined aquifers (as well as in Paleozoic rocks) in the highland regions that rim the basin. The authors developed a 13-layer, finite-element computer model of the West Siberian Basin primarily based on GIS integration of data from geologic studies. The top of the hydrologic system was assumed to coincide with a water table derived from smoothed topography and surface-water occurrences; precipitation supplied the water, and the topographic gradient of the water table supplied the driving force for ground-water flow. The general directions of calculated ground-water flow suggest that (1) the major rivers act as discharge areas, with upwelling below the rivers extending down into the basement rocks; and (2) ground-water divides that penetrate the entire thickness of the model are evident between the major rivers. Their results suggest that contaminants entering the confined aquifer system may eventually migrate to the surface, discharging within major rivers, rather than remaining confined for long travel distances within the basin sediments.

  6. UNCORRECTEDPROOF Hydrogeology and geochemistry of near-shore submarine

    E-print Network

    UNCORRECTEDPROOF Hydrogeology and geochemistry of near-shore submarine groundwater discharge rates based on tidal signal and hydraulic gradient analysis indicate a fresh submarine groundwater discharge in this high rainfall region. Ó 2007 Published by Elsevier Ltd. Keywords: submarine groundwater

  7. Hydrogeologic Controls on Bioactive Zone Development in Biostimulated Aquifers

    E-print Network

    Schillig, Peter Curtis

    2012-05-31

    This study investigates the hydrogeological factors that control the feedback between bioactive zone formation and groundwater flow, as well as developing and assessing tools useful for making these investigations. The ...

  8. HYDROGEOLOGIC CASE STUDIE(PRESENTATION FOR MNA WORKSHOP)

    EPA Science Inventory

    Hydrogeology is the foundation of subsurface site characterization for evaluations of monitored natural attenuation (MNA). Three case studies are presented. Examples of the potentially detrimental effects of drilling additives on ground-water samples from monitoring wells are d...

  9. Peatland hydrogeological function at the regional scale

    NASA Astrophysics Data System (ADS)

    Larocque, M.; Avard, K.; Pellerin, S.

    2012-12-01

    Peatlands are important components of northern landscapes. In the Canadian province of Quebec, peatlands of the St. Lawrence Valley are rapidly disappearing, threatened by rapidly growing pressures from development. Peatlands are to varying extents groundwater dependent and as such are likely to respond drastically to changes in groundwater flow conditions and to contribute to the maintenance of groundwater levels within a superficial aquifer. Yet, there is very little understanding of the hydrogeological function of peatlands at the regional scale. For this reason, they are often simply discarded in complex groundwater management decisions. The implications are not clearly understood but could lead to the disruption of ecologically important fluxes and to significant impacts for the maintenance of long term water reservoirs across the land. This study was initiated in the Centre-du-Quebec region of southern Quebec to quantify how the peatland landscape has evolved in the last decades and to understand the hydrogeological function of peatlands at the regional scale. The study area (2856 km2) is located in the St. Lawrence Lowlands. The last deglaciation has contributed to a complex stratigraphy of unconsolidated sediments and peatlands have developed at the foot of the Appalachians. A recent regional study of Quaternary deposits has shown that a majority of these peatlands are found on aeolian deposits or reworked till, while only a few are set on marine clay, littoral deposits or directly on the bedrock. The area occupied by peatlands was measured with aerial photographs dating from 1966 and 2010. In 2010, peatlands were found on 6.1 % of the territory. Of these peatlands, 10 485 ha were intact and 7 015 underwent limited perturbations (e.g. drainage ditch, forest roads). Between 1966 and 2010, nearly a quarter of the peatlands observed in 1966 underwent irreversible perturbations (e.g. agriculture, paved roads). The main cause of peatland disappearance was from cranberry crops which have been developing extremely rapidly in the study area. Nine peatlands from different parts of the study area were sampled to determine the nature of the underlying sediments. Results show that eight out of the nine studied peatlands are located on relatively permeable sand deposits and can therefore sustain hydrogeological exchanges with the surrounding aquifer. Darcy fluxes calculated from piezometric data for the nine peatlands show that five of them receive water from the superficial aquifer while four contribute water to it. Using Quaternary deposits data and a 3D hydrostratigraphic model, the proportion of peatlands receiving groundwater or contributing water to the aquifer was found to be similar at the regional scale. For the nine studied peatlands, aquifer-peatland fluxes represent between 6 and 11% of the total water input to the organic deposits. Results also show that exchanged aquifer-peatland fluxes increase with the size of the peatland, either towards the peatland or from the organic deposits to the aquifer. This study suggests that peatlands have a buffer function to keep relatively stable levels in a superficial unconsolidated aquifer. Maintaining a peatland coverage on the landscape could contribute to sustain groundwater resources.

  10. Hydrogeologic investigations at the Nevada Test Site

    SciTech Connect

    Hawkins, W.L.; Trudeau, D.A.; Drellack, S.L.

    1992-12-01

    The Nevada Test Site was established in 1950 as a continental area for testing nuclear devices and, since 1963, all nuclear detonations there have been underground. Most tests are conducted in vertical shafts with a small percentage conducted in tunnels. The majority of detonation points are above the water table, primarily in volcanic rocks or alluvium. In the testing areas the water table is 450--700 m below the surface. Pre- and post- event geologic investigations are conducted for each test location and long-term studies assess the impact of underground testing on a more regional scale. Studies in progress have not identified any impact on the regional ground water system from testing, but some local effects have been recognized. In some areas where several large tests have been conducted below the water table, water levels hundreds of meters above the regional water table have been measured and radioactivity has been discovered associated with fractures in a few holes. Flow-through and straddle packer testing has revealed unexpectedly high hydraulic pressures at depth. Recently, a multiple completion monitoring well installed to study three zones has confirmed the existence of a significant upward hydraulic gradient. These observations of local pressurization and fracture flow are being further explored to determine the influence of underground nuclear testing on the regional hydrogeologic system.

  11. Hydrogeologic investigations at the Nevada Test Site

    SciTech Connect

    Hawkins, W L; Trudeau, D A; Drellack, S L

    1992-01-01

    The Nevada Test Site was established in 1950 as a continental area for testing nuclear devices and, since 1963, all nuclear detonations there have been underground. Most tests are conducted in vertical shafts with a small percentage conducted in tunnels. The majority of detonation points are above the water table, primarily in volcanic rocks or alluvium. In the testing areas the water table is 450--700 m below the surface. Pre- and post- event geologic investigations are conducted for each test location and long-term studies assess the impact of underground testing on a more regional scale. Studies in progress have not identified any impact on the regional ground water system from testing, but some local effects have been recognized. In some areas where several large tests have been conducted below the water table, water levels hundreds of meters above the regional water table have been measured and radioactivity has been discovered associated with fractures in a few holes. Flow-through and straddle packer testing has revealed unexpectedly high hydraulic pressures at depth. Recently, a multiple completion monitoring well installed to study three zones has confirmed the existence of a significant upward hydraulic gradient. These observations of local pressurization and fracture flow are being further explored to determine the influence of underground nuclear testing on the regional hydrogeologic system.

  12. 2101-M Pond hydrogeologic characterization report

    SciTech Connect

    Chamness, M.A.; Luttrell, S.P.; Bates, D.J.; Martin, W.J.

    1990-09-01

    This report documents information collected by the Pacific Northwest Laboratory {sup (a)} at the request of Westinghouse Hanford Company. Presented in this report is the interpretation of the hydrogeologic environment at the 2101-M Pond, located in the 200-East Area of the Hanford Site. This information and its accompanying interpretation were derived from sampling and testing activities associated with the installation of four ground-water monitoring wells, in addition to data gathered from several previously existing wells. The new monitoring wells were installed as part of a groundwater monitoring program initiated in 1988. The four new monitoring wells were installed around the 2101-M Pond between May 23 and August 27, 1988. Geologic sampling, aquifer testing, and initial ground-water sampling were performed during the installation of these wells. Laboratory analyses of the sediment samples for particle size, calcium carbonate content, and selected natural and contaminant constituents were performed. A full year of quarterly ground-water sampling and the first statistical analysis of background and downgradient data have also been performed. 112 refs., 49 figs., 18 tabs.

  13. Geology and hydrogeology of the Florida Keys

    USGS Publications Warehouse

    Halley, Robert B.; Vacher, H. L.; Shinn

    1997-01-01

    This chapter discusses the geology and hydrogeology of the Florida Keys, and focuses on the islands formed of Pleistocene limestone. These islands, which are crossed when driving from Miami to Key West, are typically regarded as "the Florida Keys." The outstanding and fragile character of ecosystems on and around the Florida Keys has prompted State and Federal efforts to protect and preserve the remaining public portions of the region. The Florida Keys were largely ignored during the sixteenth, seventeenth, and eighteenth centuries, although the waters just offshore provided a major shipping thoroughfare to and from the New World. The Florida Keys are now recognized as one of the great recreational and environmental resources of the United States. The islands are outposts of a laid-back, tropical resort culture that has as its foundation warmth and clear water. A significant part of the attraction is fishing, diving, and boating around the area's coral reefs, which the islands protect. But the reefs were not always so highly valued. The Florida Keys that have protected the reefs for millennia, may now be the source of the agents that may accomplish what Agassiz thought was beyond man's power a century ago.

  14. Photogrammetry in Experiments for Hydrogeological Risk Assessment

    NASA Astrophysics Data System (ADS)

    Barazzetti, L.; Scaioni, M.; Feng, T.; Qiao, G.; Lu, P.; Tong, X.; Li, R.

    2013-01-01

    The construction of scaled-down simulation platforms is largely used to support investigations for the assessment of hydrological risk. Achieved outcomes can be integrated and assimilated to numerical analyses for the study of unstable slope collapse, debris transport, and hydrological modeling in general. During design of such simulation platforms, a relevant role has to be given to the spatial sensor network (SSN) to deploy, which is in charge of collecting geo-referenced, quantitative information during experiments. Photogrammetry (including 3D imaging sensors) can play an important role in SSN owing to its capability of collecting 2D images and 3D point clouds data covering wide surfaces without any contact. Different kinds of metric measurements can be then extracted from datasets. The aim of this paper is to give an overview and some examples on the potential of photogrammetry in hydrogeological experiments. After a general introduction on a few preliminary issues (sensors, calibration, ground reference, usage of imaging or ranging sensors), potential applications are classified into 2D and 3D categories. Examples are focused on a scaled-down landslide simulation platform developed at Tongji University (Shanghai, P. R. China).

  15. Hydrogeological controls on post-fire moss recovery in peatlands

    NASA Astrophysics Data System (ADS)

    Lukenbach, Max; Devito, Kevin; Kettridge, Nicholas; Petrone, Richard; Waddington, James

    2015-04-01

    Wildfire is the largest disturbance affecting peatlands, however, little is known about the spatiotemporal variability of post-fire recovery in these ecosystems. High water table (WT) positions after wildfire are critical to limit atmospheric carbon losses and enable the re-establishment of keystone peatland mosses (i.e. Sphagnum). While small-scale variation in burn severity can reduce capillary flow from the WT and lead to a dry surface after fire, steep WT declines can also limit post-fire moss water availability. As such, post-fire moss water availability is also a function of large-scale controls on peatland WT dynamics, specifically, connectivity to groundwater flow systems (i.e. hydrogeological setting). For this reason, we assessed the interacting controls of hydrogeological setting and burn severity on post-fire moss water availability by measuring peatland WTs, soil tension (?) and surface volumetric moisture content (?) in three burned, Sphagnum-dominated peatlands located in different hydrogeological settings for three years following wildfire. The effect of burn severity on post-fire moss water availability did not vary with hydrogeological setting, however, the spatial coverage of high and low burn severity did vary between peatlands located in different hydrogeological settings due to its influence on pre-fire fuel loads and species cover. Locations covered by S. fuscum prior to fire exhibited decreasing post-fire water availability with increasing burn severity. In contrast, the lowest water availability (? > 400 cm, ? < 0.02) was observed in feather mosses that underwent low burn severity (residual branches identifiable). Where depth of burn was > 0.05 m (high burn severity) and pre-fire species were not identifiable, water availability was highest (? < 90 cm). Where burn severity did not limit water availability through a reduction of capillary flow, depth to WT (and therefore hydrogeological setting) played a large role in affecting post-fire moss water availability. A peatland located in a groundwater flow-through system exhibited high post-fire moss water availability (surface ? > 0.15, ? < 60 cm) and shallow WTs that were less variable and exhibited lagged responses to climatic variability. In contrast, peatlands in hydrogeological settings that were not connected or ephemerally connected to groundwater flow systems exhibited deeper and more dynamic WTs that led to lower post-fire moss water availability (surface ? < 0.15, ? > 60 cm), especially during dry periods. As such, we argue that the post-fire recovery of keystone peatland mosses is strongly linked to a peatland's hydrogeological setting. These results suggest that post-fire moss re-establishment in peatlands located in dry hydrogeological settings may be particularly vulnerable to post-fire droughts and future climate change.

  16. Hydrogeologic atlas of aquifers in Indiana

    USGS Publications Warehouse

    Fenelon, Joseph M.; Bobay, K.E.; Greeman, T.K.; Hoover, M.E.; Cohen, D.A.; Fowler, K.K.; Woodfield, M.C.; and Durbin, J. M.

    1994-01-01

    Aquifers in 12 water-management basins of Indiana are identified in a series of 104 hydrogeologic sections and 12 maps that show the thickness and configuration of aquifers. The vertical distribution of water-bearing units and a generalized potentiometric profile are shown along 3,500 miles of section lines that were constructed from drillers' logs of more than 4,200 wells. The horizontal scale of the sections is 1:125,000. Maps of aquifers showing the areal distribution of each aquifer type were drawn at a scale of 1:500,000. Unconsolidated aquifers are the most widely used aquifers in Indiana and include surficial, buried, and discontinuous layers of sand and gravel. Most of the surficial sand and gravel is in large outwash plains in northern Indiana and along the major rivers. Buried sand and gravel aquifers are interbedded with till deposits in much of the northern two-thirds of Indiana. Discontinuous sand and gravel deposits are present as isolated lenses, primarily in glaciated areas. The bedrock aquifers generally have lower yields than most of the sand and gravel aquifers; however, bedrock aquifers are areally widespread and are an important source of water. Bedrock aquifer types consist of carbonates; sandstones; complexly interbedded sandstones, siltstones, shales, limestones, and coals; and an upper weathered zone in low permeability rock. Carbonate aquifers underlie about one-half of Indiana and are the most productive of the bedrock aquifers. The other principal bedrock aquifer type, sandstone, underlies large areas in the southwestern one-fifth of Indiana. No aquifer is known to be present in the southeastern corner of Indiana.

  17. DRASTIC: A STANDARDIZED SYSTEM FOR EVALUATING GROUND WATER POLLUTION USING HYDROGEOLOGIC SETTINGS

    EPA Science Inventory

    A methodology is described that will allow the pollution potential of any hydrogeologic setting to be systematically evaluated anywhere in the United States. The system has two major portions: the designation of mappable units, termed hydrogeologic settings, and the superposit...

  18. Interdisciplinary hydrogeologic site characterization at the Nevada Test Site

    SciTech Connect

    Hawkins, W.L.; Wagoner, J.L.; Drellack, S.L.

    1992-06-01

    The Nevada Test Site was established in 1950 as a continental area for testing nuclear devices. Hydrogeologic investigations began in earnest with the US Geological Survey mapping much of the area from 1960 to 1965. Since 1963, all nuclear detonations have been underground. Most tests are conducted in vertical shafts, but a small percentage are conducted in tunnels. The majority of detonation points are above the water table, primarily in volcanic rocks, but sometimes in alluvium. Hydrogeologic investigations began in earnest with the US Geological Survey`s mapping of much of the NTS region from 1960 to 1965. Following the BANEBERRY test in December 1970, which produced an accidental release of radioactivity to the atmosphere, the US Department of Energy (then the Atomic Energy Commission) established the Containment Evaluation Panel (CEP). Results of interdisciplinary hydrogeologic investigations for each test location are included in a Containment Prospectus which is thoroughly reviewed by the CEP.

  19. Interdisciplinary hydrogeologic site characterization at the Nevada Test Site

    SciTech Connect

    Hawkins, W.L. ); Wagoner, J.L. ); Drellack, S.L. )

    1992-01-01

    The Nevada Test Site was established in 1950 as a continental area for testing nuclear devices. Hydrogeologic investigations began in earnest with the US Geological Survey mapping much of the area from 1960 to 1965. Since 1963, all nuclear detonations have been underground. Most tests are conducted in vertical shafts, but a small percentage are conducted in tunnels. The majority of detonation points are above the water table, primarily in volcanic rocks, but sometimes in alluvium. Hydrogeologic investigations began in earnest with the US Geological Survey's mapping of much of the NTS region from 1960 to 1965. Following the BANEBERRY test in December 1970, which produced an accidental release of radioactivity to the atmosphere, the US Department of Energy (then the Atomic Energy Commission) established the Containment Evaluation Panel (CEP). Results of interdisciplinary hydrogeologic investigations for each test location are included in a Containment Prospectus which is thoroughly reviewed by the CEP.

  20. Groundwater availability as constrained by hydrogeology and environmental flows

    USGS Publications Warehouse

    Watson, Katelyn A.; Mayer, Alex S.; Reeves, Howard W.

    2014-01-01

    Groundwater pumping from aquifers in hydraulic connection with nearby streams has the potential to cause adverse impacts by decreasing flows to levels below those necessary to maintain aquatic ecosystems. The recent passage of the Great Lakes-St. Lawrence River Basin Water Resources?Compact has brought attention to this issue in the Great Lakes region. In particular, the legislation requires the Great Lakes states to enact measures for limiting water withdrawals that can cause adverse ecosystem impacts. This study explores how both hydrogeologic and environmental flow limitations may constrain groundwater availability in the Great Lakes Basin. A methodology for calculating maximum allowable pumping rates is presented. Groundwater availability across the basin may be constrained by a combination of hydrogeologic yield and environmental flow limitations varying over both local and regional scales. The results are sensitive to factors such as pumping time, regional and local hydrogeology, streambed conductance, and streamflow depletion limits. Understanding how these restrictions constrain groundwater usage and which hydrogeologic characteristics and spatial variables have the most influence on potential streamflow depletions has important water resources policy and management implications.

  1. An integrated theoretical and practical approach for teaching hydrogeology

    NASA Astrophysics Data System (ADS)

    Bonomi, Tullia; Fumagalli, Letizia; Cavallin, Angelo

    2013-04-01

    Hydrogeology as an earth science intersects the broader disciplines of geology, engineering, and environmental studies but it does not overlap fully with any of them. It is focused on its own range of problems and over time has developed a rich variety of methods and approaches. The resolution of many hydrogeological problems requires knowledge of elements of geology, hydraulics, physics and chemistry; moreover in recent years the knowledge of modelling techniques has become a necessary ability. Successful transfer of all this knowledge to the students depends on the breadth of material taught in courses, the natural skills of the students and any practical experience the students can obtain. In the Department of Earth and Environmental Sciences of the University of Milano-Bicocca, the teaching of hydrogeology is developed in three inter-related courses: 1) general hydrogeology, 2) applied hydrogeology, 3) groundwater pollution and remediation. The sequence focuses on both groundwater flux and contaminant transport, supplemented by workshops involving case studies and computer labs, which provide the students with practical translation of the theoretical aspects of the science into the world of work. A second key aspect of the program utilizes the students' skill at learning through online approaches, and this is done through three approaches: A) by developing the courses on a University e-learning platform that allows the students to download lectures, articles, and teacher comments, and to participate in online forums; B) by carring out exercises through computer labs where the student analyze and process hydrogeological data by means of different numerical codes, that in turn enable them to manage databases and to perform aquifer test analysis, geostatistical analysis, and flux and transport modelling both in the unsaturated and saturated zone. These exercises are of course preceded by theoretical lectures on codes and software, highlighting their features and their limitations; C) by an evaluation process whose results contribute to the final examination, so that the students are evaluated on the basis of their ability to discuss theoretical subjects and/or projects and to resolving exercises and case studies either by hand calculations or by modelling. The applied hydrogeology examination is an example of the evaluation process. It involves development of a plan to resolve a real hydrogeological issue, such as the design of a hydraulic barrier for a landfill, the design of a well field to meet the supply requirements of a muncipality, or the control of possible seepage from a contaminated site close to to sensitive discharge features such as wells, springs, rivers. The students are allowed to work on computers for three consecutive mornings for a total 15 hours, and in the end are required to produce a technical report and a hydrogeological model. Obviously their solutions are neither unique nor completely optimized (just as in the real world), but the comparisons and debates among the students are important portals to learning and improvement. A second example: the groundwater pollution and remediation examination is based on the discussion of a remediation project elaborated in stages during the course, with the addition of increasing complex types of data and information. The students have one hour a week, during the course, to submit to the teacher their analysis of the problem and possible solutions. In ten years of experience all students have considered this method of examination a challenge, and found it engaging and helpful, even if unusual, at least in Italy. The University of Milano Bicocca has recently drilled a piezometric well both to monitor the flow of groundwater and to allow students to perform aquifer tests and to conduct standard groundwater sampling procedure, without any longer needing to rely on outside private donors for access to a field site. The overall approach, which includes, lectures, exercises, modelling and applied projects, help the students to consider hydrogeology from various poi

  2. Hydrogeologic data from parts of the Denver Basin, Colorado

    USGS Publications Warehouse

    Major, T.J.; Robson, S.G.; Romero, J.C.; Zawistowski, Stanley

    1983-01-01

    This report presents hydrogeologic data collected and compiled during 1956-81 as part of a comprehensive hydrogeologic data collected and compiled during 1956-81 as part of a comprehensive hdryogeologic investigation of the Denver basin, Colorado, by the U.S. Geological Survey in cooperation with the Colorado Department of Natural Resources, Division of Water Resources, Office of the State Engineer. The data, in tabular and graphic form, consist of records for 870 wells which include water-level data for 158 wells and water-quality analyses for 561 wells; geophysical logs from three wells which include resistivity, self potential, and natural gamma logs; and gain-and-loss data of streamflow measured at 54 sites. (USGS)

  3. HYDROGEOLOGIC CHARACTERIZATION OF THE U-3bl COLLAPSE ZONE

    SciTech Connect

    Bechtel Nevada and National Security Technologies, LLC

    2006-09-01

    The U-3bl collapse crater was formed by an underground nuclear test in August 1962. This crater and the adjoining U-3ax crater were subsequently developed and used as a bulk low-level radioactive waste disposal cell (U-3ax/bl), which is part of the Area 3 Radioactive Waste Management Site at the Nevada Test Site (NTS). Various investigations have been conducted to assess the hydrogeologic characteristics and properties in the vicinity of the U-3ax/bl waste disposal cell. This report presents data from one of these investigations, conducted in 1996. Also included in this report is a review of pertinent nuclear testing records, which shows that the testing operations and hydrogeologic setting of the U-3ax/bl site were typical for the period and location of testing.

  4. The hydrogeologic-geochemical model of Cerro Prieto revisited

    SciTech Connect

    Lippmann, M.J.; Halfman, S.E.; Truesdell, A.H.; Manon M., A.

    1989-01-01

    As the exploitation of the Cerro Prieto, Mexico, geothermal field continues, there is increasing evidence that the hydrogeologic model developed by Halfman et al. (1984, 1986) presents the basic features controlling the movement of geothermal fluids in the system. At the present time the total installed capacity at Cerro Prieto is 620 MWe requiring the production of more than 10,500 tonnes/hr of a brine-steam mixture. This significant rate of fluid production has resulted in changes in reservoir thermodynamic conditions and in the chemistry of the produced fluids. After reviewing the hydrogeologic-geochemical model of Cerro Prieto, some of the changes observed in the field due to its exploitation are discussed and interpreted on the basis of the model. 21 refs., 11 figs., 1 tab.

  5. Hydrogeologic Framework of Onslow County, North Carolina, 2008

    USGS Publications Warehouse

    Fine, Jason M.

    2008-01-01

    The unconsolidated sediments that underlie the Onslow County area are composed of interlayered permeable and impermeable beds, which overlie the crystalline basement rocks. The aquifers, composed mostly of sand and limestone, are separated by confining units composed mostly of clay and silt. The aquifers from top to bottom are the surficial, Castle Hayne, Beaufort, Peedee, Black Creek, and Upper and Lower Cape Fear aquifers. For this study, the Castle Hayne aquifer is informally divided into the upper and lower Castle Hayne aquifers. The eight aquifers and seven confining units of the Tertiary and Cretaceous strata beneath Onslow County are presented in seven hydrogeologic sections. The hydrogeologic framework was refined from existing interpretations by using geophysical logs, driller's logs, and other available data from 123 wells and boreholes.

  6. Hydrogeologic model of the Ahuachapan geothermal field, El Salvador

    SciTech Connect

    Laky, C.; Lippmann, M.J.; Bodvarsson, G.S. ); Retana, M.; Cuellar, G. )

    1989-01-01

    A hydrogeological model of the Ahuachapan geothermal field has been developed. It considers the lithology and structural features of the area and discerns their impact on the movement of cold and hot fluids in the system. Three aquifers were identified, their zones of mixing and flow patterns were obtained on the basis of temperature and geochemical data from wells and surface manifestations. 12 refs., 9 figs.

  7. Developing Hydrogeological Site Characterization Strategies based on Human Health Risk

    NASA Astrophysics Data System (ADS)

    de Barros, F.; Rubin, Y.; Maxwell, R. M.

    2013-12-01

    In order to provide better sustainable groundwater quality management and minimize the impact of contamination in humans, improved understanding and quantification of the interaction between hydrogeological models, geological site information and human health are needed. Considering the joint influence of these components in the overall human health risk assessment and the corresponding sources of uncertainty aid decision makers to better allocate resources in data acquisition campaigns. This is important to (1) achieve remediation goals in a cost-effective manner, (2) protect human health and (3) keep water supplies clean in order to keep with quality standards. Such task is challenging since a full characterization of the subsurface is unfeasible due to financial and technological constraints. In addition, human exposure and physiological response to contamination are subject to uncertainty and variability. Normally, sampling strategies are developed with the goal of reducing uncertainty, but less often they are developed in the context of their impacts on the overall system uncertainty. Therefore, quantifying the impact from each of these components (hydrogeological, behavioral and physiological) in final human health risk prediction can provide guidance for decision makers to best allocate resources towards minimal prediction uncertainty. In this presentation, a multi-component human health risk-based framework is presented which allows decision makers to set priorities through an information entropy-based visualization tool. Results highlight the role of characteristic length-scales characterizing flow and transport in determining data needs within an integrated hydrogeological-health framework. Conditions where uncertainty reduction in human health risk predictions may benefit from better understanding of the health component, as opposed to a more detailed hydrogeological characterization, are also discussed. Finally, results illustrate how different dose-response models can impact the probability of human health risk exceeding a regulatory threshold.

  8. Characterization of hydrogeologic units using matrix properties, Yucca Mountain, Nevada

    USGS Publications Warehouse

    Flint, L.E.

    1998-01-01

    Determination of the suitability of Yucca Mountain, in southern Nevada, as a geologic repository for high-level radioactive waste requires the use of numerical flow and transport models. Input for these models includes parameters that describe hydrologic properties and the initial and boundary conditions for all rock materials within the unsaturated zone, as well as some of the upper rocks in the saturated zone. There are 30 hydrogeologic units in the unsaturated zone, and each unit is defined by limited ranges where a discrete volume of rock contains similar hydrogeologic properties. These hydrogeologic units can be easily located in space by using three-dimensional lithostratigraphic models based on relation- ships of the properties with the lithostratigraphy. Physical properties of bulk density, porosity, and particle density; flow properties of saturated hydraulic conductivity and moisture-retention characteristics; and the state variables (variables describing the current state of field conditions) of saturation and water potential were determined for each unit. Units were defined using (1) a data base developed from 4,892 rock samples collected from the coring of 23 shallow and 8 deep boreholes, (2) described lithostratigraphic boundaries and corresponding relations to porosity, (3) recognition of transition zones with pronounced changes in properties over short vertical distances, (4) characterization of the influence of mineral alteration on hydrologic properties such as permeability and moisture-retention characteristics, and (5) a statistical analysis to evaluate where boundaries should be adjusted to minimize the variance within layers. This study describes the correlation of hydrologic properties to porosity, a property that is well related to the lithostratigraphy and depositional and cooling history of the volcanic deposits and can, therefore, be modeled to be distributed laterally. Parameters of the hydrogeologic units developed in this study and the relation of flow properties to porosity that are described can be used to produce detailed and accurate representations of the core-scale hydrologic processes ongoing at Yucca Mountain.

  9. Hydrogeologic framework of the Michigan Basin regional aquifer system

    USGS Publications Warehouse

    Westjohn, David B.; Weaver, T.L.

    1998-01-01

    This study describes the geologic and hydrogeologic units that form the Michigan Basin regional aquifer system; delineates boundaries of aquifers and confining units; describes hydraulic properties of aquifers and confining units used as parameters for computer simulation of ground-water flow; delineates the configuration of the base of freshwater and approximates the boundary between saline water and brine; and describes the geologic controls on the position of the transition zone between freshwater and saline water.

  10. Geological realism in hydrogeological and geophysical inverse modeling: A review

    NASA Astrophysics Data System (ADS)

    Linde, Niklas; Renard, Philippe; Mukerji, Tapan; Caers, Jef

    2015-12-01

    Scientific curiosity, exploration of georesources and environmental concerns are pushing the geoscientific research community toward subsurface investigations of ever-increasing complexity. This review explores various approaches to formulate and solve inverse problems in ways that effectively integrate geological concepts with geophysical and hydrogeological data. Modern geostatistical simulation algorithms can produce multiple subsurface realizations that are in agreement with conceptual geological models and statistical rock physics can be used to map these realizations into physical properties that are sensed by the geophysical or hydrogeological data. The inverse problem consists of finding one or an ensemble of such subsurface realizations that are in agreement with the data. The most general inversion frameworks are presently often computationally intractable when applied to large-scale problems and it is necessary to better understand the implications of simplifying (1) the conceptual geological model (e.g., using model compression); (2) the physical forward problem (e.g., using proxy models); and (3) the algorithm used to solve the inverse problem (e.g., Markov chain Monte Carlo or local optimization methods) to reach practical and robust solutions given today's computer resources and knowledge. We also highlight the need to not only use geophysical and hydrogeological data for parameter estimation purposes, but also to use them to falsify or corroborate alternative geological scenarios.

  11. Summary of Hydrogeologic Conditions by County for the State of Michigan

    USGS Publications Warehouse

    Apple, Beth A.; Reeves, Howard W.

    2007-01-01

    Summaries of the major hydrogeologic features for each county in Michigan are presented. Each summary includes a listing of the major watersheds in the county and a description of the hydrogeology of the major aquifers in the county. Aquifer properties reported in the literature are given if available. Reports describing the hydrogeology of each county are cited. This work was prepared to provide a brief introduction to the ground-water setting for each county.

  12. Hydrogeological controls on post-fire moss recovery in peatlands

    NASA Astrophysics Data System (ADS)

    Lukenbach, M. C.; Devito, K. J.; Kettridge, N.; Petrone, R. M.; Waddington, J. M.

    2015-11-01

    Wildfire is the largest disturbance affecting boreal peatlands, however, little is known about the controls on post-fire peatland vegetation recovery. While small-scale variation in burn severity can reduce post-fire moss water availability, high water table (WT) positions following wildfire are also critical to enable the re-establishment of keystone peatland mosses (i.e. Sphagnum). Thus, post-fire moss water availability is also likely a function of landscape-scale controls on peatland WT dynamics, specifically, connectivity to groundwater flow systems (i.e. hydrogeological setting). For this reason, we assessed the interacting controls of hydrogeological setting and burn severity on post-fire moss water availability in three burned, Sphagnum-dominated peatlands in Alberta's Boreal Plains. At all sites, variation in burn severity resulted in a dichotomy between post-fire surface covers that: (1) exhibited low water availability, regardless of WT position, and had minimal (<5%) moss re-establishment (i.e. lightly burned feather mosses and severely burned Sphagnum fuscum) or (2) exhibited high water availability, depending on WT position, and had substantial (>50%) moss re-establishment (i.e. lightly burned S. fuscum and where depth of burn was >0.05 m). Notably, hydrogeological setting influenced the spatial coverage of these post-fire surface covers by influencing pre-fire WTs and stand characteristics (e.g., shading). Because feather moss cover is controlled by tree shading, lightly burned feather mosses were ubiquitous (>25%) in drier peatlands (deeper pre-fire WTs) that were densely treed and had little connection to large groundwater flow systems. Moreover, hydrogeological setting also controlled post-fire WT positions, thereby affecting moss re-establishment in post-fire surface covers that were dependent on WT position (e.g., lightly burned S. fuscum). Accordingly, higher recolonization rates were observed in a peatland located in a groundwater flow through system that had a shallow post-fire WT. Therefore, we argue that hydrogeological setting influences post-fire recovery in two ways: (1) by influencing vegetation structure prior to wildfire, thereby controlling the coverage of post-fire surface covers and (2) by influencing post-fire WT positions. These results suggest that post-fire moss recovery in peatlands isolated from groundwater flow systems may be particularly susceptible to droughts and future climate change.

  13. Characterization of hydrogeologic units using matrix properties, Yucca Mountain, Nevada

    SciTech Connect

    Flint, L.E.

    1998-09-01

    Determination of the suitability of Yucca Mountain, in southern Nevada, as a geologic repository for high-level radioactive waste requires the use of numerical flow and transport models. Input for these models includes parameters that describe hydrologic properties and the initial and boundary conditions for all rock materials within the unsaturated zone, as well as some of the upper rocks in the saturated zone. There are 30 hydrogeologic units in the unsaturated zone, and each unit is defined by limited ranges where a discrete volume of rock contains similar hydrogeologic properties. These hydrogeologic units can be easily located in space by using three-dimensional lithostratigraphic models based on relationships of the properties with the lithostratigraphy. Physical properties of bulk density, porosity, and particle density; flow properties of saturated hydraulic conductivity and moisture-retention characteristics; and the state variables (variables describing the current state of field conditions) of saturation and water potential were determined for each unit. Units were defined using (1) a data base developed from 4,892 rock samples collected from the coring of 23 shallow and 8 deep boreholes, (2) described lithostratigraphic boundaries and corresponding relations to porosity, (3) recognition of transition zones with pronounced changes in properties over short vertical distances, (4) characterization of the influence of mineral alteration on hydrologic properties such as permeability and moisture-retention characteristics, and (5) a statistical analysis to evaluate where boundaries should be adjusted to minimize the variance within layers. This study describes the correlation of hydrologic properties to porosity, a property that is well related to the lithostratigraphy and depositional and cooling history of the volcanic deposits and can, therefore, be modeled to be distributed laterally.

  14. Hydrogeologic data for selected coal areas, east-central Montana

    USGS Publications Warehouse

    Roberts, Robert S.

    1980-01-01

    Hydrogeologic data were collected in selected coal areas of east-central Montana to provide a basis for evaluating the effects of future coal development on the groundwater resources. Inventory records for 916 domestic, stock, public supply, commercial, and test wells are tabulated in the report; the data were collected principally from 1975 through 1976. The locations of the wells are shown on a map at a scale of 1:250,000. Lithologic logs are also included for 149 wells. Chemical analyses of water samples from selected wells consist of 167 samples analyzed for major cations and anions and 24 samples analyzed for miscellaneous constituents. (USGS)

  15. Hydrogeologic Assessment of the Pixley National WildlifeRefuge

    SciTech Connect

    Quinn, Nigel W.T.

    2007-10-01

    A hydrogeological assessment of Pixley National Wildlife Refuge was conducted using published reports from the USGS and private engineering consultants that pertained to land in close proximity to the Refuge and from monitoring conducted by refuge staff in collaboration with Reclamation. The compiled data clearly show that there are a large number of agricultural wells throughout the Basin and that water levels are responsive to rates of pumping - in some cases declining more than 100 ft in a matter of a few years. Aquifer properties support a groundwater conjunctive use solution to the provision of additional water supply to the Refuge. The report provides justification for this approach.

  16. 3D Hydrogeological Modeling of Impact from Tunneling

    NASA Astrophysics Data System (ADS)

    Kohl, T.; Megel, T.

    2005-12-01

    With the goal of reproduction the subsurface flow paths for an environmental impact study a three-dimensional hydraulic model of an major Austrian tunnel was developed in 2001 in a first phase. The model encompassed a regional scale of more than 1000 km2. Therewith, the combined geological, hydraulic and geothermal situation as well as hydrogeologically critical zones along the tunnel axis could be highlighted. Based on a further elaborated regional geological / hydrogeological conceptual model, a 2nd project phase started in 2004 with an even more sophisticated regional model that concentrates on the near tunnel realm. In the vicinity of the tunnel, a strongly refined numerical finite element mesh allows the calculation of the strong hydraulic gradients that develop near the tunnel wall. The model now includes the tunnel construction with a defined diameter and follows the path of the tunnel axis. Therefore, the full three-dimensionality of the construction and the recognized geological / hydrogeological structures are integrated in a single numerical model. In the case of this project two models have been developed, one each for the area East and West of the divide along the Mountain allowing the simulation to cover the total tunnel length of approx.45 km. In parallel, the model includes the hydrogeological findings from various investigation boreholes and the infiltration from measuring campaigns performed to date. The definition of hydraulic boundary conditions turned out to have the largest influence on the quality of the numerical results. By adopting a strategy that defines both Neuman (at higher altitude range) and Dirichlet boundary conditions (at lower altitude range) this problem was well treated. In our contribution, it is demonstrated that a mesh of nearly half a million nodes can be set up that accounts for nearly arbitrary geological settings but also for the refined representation of subsurface constructions. It may be noted that these accomplishments need to be combined with an adequate finite element formulation. In our case, the treatment of a series of element types (in 3D: hexahedrons, pyramids, tetrahedrons or prisms) is indispensable. This way, the further impact on poroelastic processes like subsidence can also simulated.

  17. Proceedings of the joint Russian-American hydrogeology seminar

    SciTech Connect

    Tsang, C.F.; Mironenko, V.; Pozdniakov, S.

    1997-12-31

    Hydrogeology research has been very active in both Russia and the US because of the concerns for migration of radioactive and chemical contaminants in soils and geologic formations, as well as for water problems related to mining and other industrial operations. Russian hydrogeologists have developed various analysis and field testing techniques, sometimes in parallel with US counterparts. These Proceedings come out of a Seminar held to bring together a small group (about 15) of active Russian researchers in geologic flow and transport associated with the disposal of radioactive and chemical wastes either on the soils or through deep injection wells, with a corresponding group (about 25) of American hydrogeologists. The meeting was intentionally kept small to enable informal, detailed and in-depth discussions on hydrogeological issues of common interest. Out of this interaction, the authors hope that, firstly, they will have learned from each other and secondly, that research collaborations will be established where there is the opportunity. This proceedings presents the summaries and viewgraphs from the presentations. What cannot be conveyed here is the warm and cooperative atmosphere of these interactions, both inside and outside the formal sessions, which may well lead to future collaborations.

  18. Forensic analysis of MTBE contamination using basic hydrogeologic concepts.

    PubMed

    Boving, Thomas

    2014-07-01

    Contamination of groundwater with petroleum hydrocarbons and additives, such as methyl tert-butyl ether (MTBE), is often linked to the leaking product distribution system of gas stations. In very few cases is it know if and when a leak occurred and how much product was released to the environment. In the absence of direct evidence, a careful analysis of the available data, such as contaminant breakthrough at receptor wells or discrepancies in the product inventory data, may provide evidence about the nature of the release, its timing and magnitude. Using a MTBE contamination site in the formerly glaciated New England region as an example, two possible release scenarios (slow, long-term release vs. spill) were examined. Of the two scenarios, the slow release could be ruled out as the sole source even though there was no direct evidence for a spill. The analysis of hydraulic test results together with chemical data further permitted to estimate when such an undocumented spill might have occurred. Analyses of the data also allowed these results to be compared to that of a prior transport and fate modeling study. Good agreement and consistency for contaminant travel times was confirmed. This forensic analysis demonstrates that applying basic hydrogeologic principles can aide in the reconstruction of contamination events while providing more readily understandable and defendable evidence relative to complex models. Conceptually, the approach described herein is transferable to other sites with similar hydrogeologies. PMID:24840309

  19. Flawed processing of airborne EM data affecting hydrogeological interpretation.

    PubMed

    Viezzoli, Andrea; Jørgensen, Flemming; Sørensen, Camilla

    2013-03-01

    Airborne electromagnetics (AEMs) is increasingly being used across the globe as a tool for groundwater and environmental management. Focus is on ensuring the quality of the source data, their processing and modeling, and the integration of results with ancillary information to generate accurate and relevant products. Accurate processing and editing of raw AEM data, the topic of this article, is one of the crucial steps in obtaining quantitative information for groundwater modeling and management. In this article, we examine the consequences that different levels of processing of helicopter transient electromagnetic method data have on the resulting electrical models and subsequently on hydrogeological models. We focus on different approaches used in the industry for processing of the raw data and show how the electrical resistivity-depth models, which is the end "geophysical" product (after data inversion) of an AEM survey, change with different levels of processing of the raw data. We then extend the study to show the impact on some of the hydrogeological parameters or models, which can be derived from the geophysical results. The consequences of improper handling of raw data to groundwater and environmental management can be significant and expensive. PMID:22775586

  20. The application of seismic techniques to hydrogeological investigations

    NASA Astrophysics Data System (ADS)

    Jarvis, Kevin Donald Gibson

    The objective of this thesis is to demonstrate some new applications of seismic techniques for hydrogeological applications. A compressional-wave, surface-based, reflection seismic technique is used to map aquifer boundaries within a series of Pleistocene near-surface sediments. The interpretation uses both water wells and sequence stratigraphic concepts to identify the boundaries of new and existing aquifers. The use of the cone penetrometer is an integral part of this thesis. The seismic cone is demonstrated to be both cost-effective and reliable for the acquisition of high-quality vertical seismic profile (VSP) data. Other data from the cone, in particular the tip resistance data, are shown to be an integral link for the conversion of shear-wave velocities to values of hydraulic conductivity. Surface-based, shear-wave reflection seismic data are used to image an aquifer contained within Holocene deltaic sediments. A Bayesian inversion of the shear-wave seismic amplitudes (using cone-derived velocities) results in the generation of a two-dimensional profile of shear-wave velocity that is a direct indication of aquifer heterogeneity. Conversion of the velocity to hydraulic conductivity (using a cone-derived relationship) results in the distribution of a key hydrogeologic property within the aquifer. The results from the thesis show significant promise for improving groundwater flow models and providing new techniques for the management and protection of our groundwater resources.

  1. Hydrogeologic framework of the middle San Pedro watershed, southeastern Arizona

    USGS Publications Warehouse

    Dickinson, Jesse E.; Kennedy, Jeffrey R.; Pool, D.R.; Cordova, Jeffrey T.; Parker, John T.; Macy, J.P.; Thomas, Blakemore

    2010-01-01

    Water managers in rural Arizona are under increasing pressure to provide sustainable supplies of water despite rapid population growth and demands for environmental protection. This report describes the results of a study of the hydrogeologic framework of the middle San Pedro watershed. The components of this report include: (1) a description of the geologic setting and depositional history of basin fill sediments that form the primary aquifer system, (2) updated bedrock altitudes underlying basin fill sediments calculated using a subsurface density model of gravity data, (3) delineation of hydrogeologic units in the basin fill using lithologic descriptions in driller's logs and models of airborne electrical resistivity data, (4) a digital three-dimensional (3D) hydrogeologic framework model (HFM) that represents spatial extents and thicknesses of the hydrogeologic units (HGUs), and (5) description of the hydrologic properties of the HGUs. The lithologic interpretations based on geophysical data and unit thickness and extent of the HGUs included in the HFM define potential configurations of hydraulic zones and parameters that can be incorporated in groundwater-flow models. The hydrogeologic framework comprises permeable and impermeable stratigraphic units: (1) bedrock, (2) sedimentary rocks predating basin-and-range deformation, (3) lower basin fill, (4) upper basin fill, and (5) stream alluvium. The bedrock unit includes Proterozoic to Cretaceous crystalline rocks, sedimentary rocks, and limestone that are relatively impermeable and poor aquifers, except for saturated portions of limestone. The pre-basin-and-range sediments underlie the lower basin fill but are relatively impermeable owing to cementation. However, they may be an important water-bearing unit where fractured. Alluvium of the lower basin fill, the main water-bearing unit, was deposited in the structural trough between the uplifted ridges of bedrock and (or) pre-basin-and-range sediments. Alluvium of the upper basin fill may be more permeable than the lower basin fill, but it is generally unsaturated in the study area. The lower basin fill stratigraphic unit was delineated into three HGUs on the basis of lithologic descriptions in driller?s logs and one-dimensional (1D) electrical models of airborne transient electromagnetic (TEM) surveys. The interbedded lower basin fill (ILBF) HGU represents an upper sequence having resistivity values between 5 and 40 ohm-m identified as interbedded sand, gravel, and clay in driller?s logs. Below this upper sequence, fine-grained lower basin fill (FLBF) HGU represents a thick silt and clay sequence having resistivity values between 5 and 20 ohm-m. Within the coarse-grained lower basin fill (CLBF) HGU, which underlies the silt and clay of the FLBF, the resistivity values on logs and 1D models increase to several hundred ohm-m and are highly variable within sand and gravel layers. These sequences match distinct resistivity and lithologic layers identified by geophysical logs in the adjacent Sierra Vista subwatershed, suggesting that these sequences are laterally continuous within both the Benson and Sierra Vista subwatersheds in the Upper San Pedro Basin. A subsurface density model based on gravity data was constructed to identify the top of bedrock and structures that may affect regional groundwater flow. The subsurface density model contains six layers having uniform density values, which are assigned on the basis of geophysical logs. The density values for the layers range between 1.65 g/cm3 for unsaturated sediments near the land surface and 2.67 g/cm3 for bedrock. Major features include three subbasins within the study area, the Huachuca City subbasin, the Tombstone subbasin, and the Benson subbasin, which have no expression in surface topography or lithology. Bedrock altitudes from the subsurface density model defined top altitudes of the bedrock HGU. The HFM includes the following HGUs in ascending stratigr

  2. GIS-based hydrogeological databases and groundwater modelling

    NASA Astrophysics Data System (ADS)

    Gogu, Radu Constantin; Carabin, Guy; Hallet, Vincent; Peters, Valerie; Dassargues, Alain

    2001-12-01

    Reliability and validity of groundwater analysis strongly depend on the availability of large volumes of high-quality data. Putting all data into a coherent and logical structure supported by a computing environment helps ensure validity and availability and provides a powerful tool for hydrogeological studies. A hydrogeological geographic information system (GIS) database that offers facilities for groundwater-vulnerability analysis and hydrogeological modelling has been designed in Belgium for the Walloon region. Data from five river basins, chosen for their contrasting hydrogeological characteristics, have been included in the database, and a set of applications that have been developed now allow further advances. Interest is growing in the potential for integrating GIS technology and groundwater simulation models. A "loose-coupling" tool was created between the spatial-database scheme and the groundwater numerical model interface GMS (Groundwater Modelling System). Following time and spatial queries, the hydrogeological data stored in the database can be easily used within different groundwater numerical models. Résumé. La validité et la reproductibilité de l'analyse d'un aquifère dépend étroitement de la disponibilité de grandes quantités de données de très bonne qualité. Le fait de mettre toutes les données dans une structure cohérente et logique soutenue par les logiciels nécessaires aide à assurer la validité et la disponibilité et fournit un outil puissant pour les études hydrogéologiques. Une base de données pour un système d'information géographique (SIG) hydrogéologique qui offre toutes les facilités pour l'analyse de la vulnérabilité des eaux souterraines et la modélisation hydrogéologique a été établi en Belgique pour la région Wallonne. Les données de cinq bassins de rivières, choisis pour leurs caractéristiques hydrogéologiques différentes, ont été introduites dans la base de données, et un ensemble d'applications qui ont été développées permet dès maintenant de prochaines avancées. L'intérêt grandit pour le potentiel d'intégration de la technologie des SIG et les modèles de simulation des nappes. Un outil de couplage a été créé entre le schéma de base de données spatiales et l'interface GMS (GroundWater Modelling System, système de modélisation de nappe) du modèle numérique de nappe. Suivant les requêtes en fonction du temps et de l'espace, les données hydrogéologiques stockées dans la base de données peuvent être aisément utilisées dans différents modèles numériques de nappes. Resumen. La fiabilidad y validez de los análisis de aguas subterráneas dependen enormemente de la disponibilidad de muchos datos de alta calidad. Integrarlos en una estructura consistente y lógica mediante un entorno informático sirve para asegurar su validez y disponibilidad, y rrepresenta una herramienta muy potente para ulteriores estudios hidrogeológicos. Se ha diseñado en la región de Valonia (Bélgica) una base de datos hidrogeológica basada en un sistema de información geográfica (GIS), con el que se dispone de útiles para elaborar análisis de vulnerabilidad y modelos hidregeológicos. Se ha utilizado datos de cinco cuencas fluviales, elegidas por sus características hidrogeológicas contrastadas, así como un conjunto de aplicaciones desarrolladas con vistas al futuro. El interés por el potencial que ofrece la integración de la tecnología GIS y los modelos de simulación de aguas subterráneas está en auge. Se ha desarrollado un "emulador" que integra el esquema espacial de la base de datos y la interfaz GMS (GroundWater Modelling System) de modelación numérica de aguas subterráneas. A partir de búsquedas temporales y espaciales, los datos hidrogeológicos almacenados en la base de datos pueden ser utilizados fácilmente en modelos numéricos diferentes de aguas subterráneas.

  3. Importance of Hydrogeological Conditions on Open-loop Geothermal System

    NASA Astrophysics Data System (ADS)

    Park, D.; Bae, G.; Kim, S.; Lee, K.

    2013-12-01

    The open-loop geothermal system has been known as an eco-friendly, energy-saving, and cost-efficient alternative for the cooling and heating of buildings with directly using the relatively stable temperature of groundwater. Thus, hydrogeological properties of aquifer, such as hydraulic conductivity and storage, must be important in the system application. The study site is located near Han-river, Korea, and because of the well-developed alluvium it might be a typical site appropriate to this system requiring an amount of groundwater. In this study, the first objective of numerical experiments was to find the best distributions of pumping and injection wells suitable to the hydrogeological conditions of the site for the efficient and sustainable system operation. The aquifer has a gravel layer at 15m depth below the ground surface and the river and the agricultural field, which may be a potential contaminant source, are located at the west and east sides, respectively. Under the general conditions that the regional groundwater flows from the east to the river, the locally reversed well distribution, locating the pumping well at upgradient and the injection well at downgradient of the regional flow, was most sustainable. The gravel layer with high hydraulic conductivity caused a little drawdown despite of an amount of pumping and allowed to stably reinject the used groundwater in all the cases, but it provided a passage transferring the injected heat to the pumping well quickly, particularly in the cases locating the injection well at the upgradient. This thermal interference was more severe in the cases of the short distance between the wells. The high conductive layer is also a reason that the seasonal role conversion of wells for the aquifer thermal energy storage was ineffective in this site. Furthermore, the well distribution vertical to the regional groundwater flow was stable, but not best, and, thus, it may be a good choice in the conditions that the regional groundwater flow direction has often been changed. Any effects of the seasonal river temperature variation and contaminant sources were not found on the wells because of the well screen installed at only the relatively deep gravel layer. Finally, it was evaluated whether if these results are valid in a homogeneous aquifer with the full screen of wells and the aquifer having a sediment layer with high hydraulic conductivity at a shallow depth, which are also typical aquifers near river. All the results concluded that it is essential to investigate and understand the site-specific hydrogeological conditions for the successful application of open-loop geothermal system.

  4. Hydrogeological Methods for Assessing Feasibility of Artificial Recharge

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

    This study presents the hydrogeological methods to assess the feasibility of artificial recharge in Jeju Island, Korea for securing both sustainable groundwater resources and severe floods. Jeju-friendly Aquifer Recharge Technology (J-ART) in this study is developing by capturing ephemeral stream water with no interference in the environments such as natural recharge or eco-system, storing the flood water in the reservoirs, recharging it through designed borehole after appropriate water treatment, and then making it to be used at down-gradient production wells. Many hydrogeological methods, including physico-chemical surface water and groundwater monitoring, geophysical survey, stable isotope analysis, and groundwater modeling have been employed to predict and assess the artificially recharged surface waters flow and circulation between recharge area and discharge area. In the study of physico-chemical water monitoring survey, the analyses of surface water level and velocity, of water qualities including turbidity, and of suspended soil settling velocity were performed. For understanding subsurface hydrogeologic characteristics the injection test was executed and the results are 118-336 m2/day of transmissivity and 4,367-11,032 m3/day of the maximum intake water capacity. Characterizing groundwater flow from recharge area to discharge area should be achieved to assess the efficiency of J-ART. The resistivity logging was carried out to predict water flow in unsaturated zone during artificial recharge based on the inverse modeling and resistivity change patterns. Stable isotopes of deuterium and oxygen-18 of surface waters and groundwaters have been determined to interpret mixing and flow in groundwaters impacted by artificial recharge. A numerical model simulating groundwater flow and heat transport to assess feasibility of artificial recharge has been developed using the hydraulic properties of aquifers, groundwater levels, borehole temperatures, and meteorological data. Also, groundwater modeling was performed to aid in artificial recharge system design, such as optimizing number and spacing of injection wells, building up and maintaining a water column inside each operating injection well, and optimizing time. Acknowledgements This research was supported by a grant (code 3-2-3) from the Sustainable Water Resources Research Center of 21st Century Frontier Research Program and the Basic Research Program (09-3414) of KIGAM.

  5. Unraveling complex hydrogeologic systems using field tracer tests

    NASA Astrophysics Data System (ADS)

    Dam, William A.; Nicholson, Thomas

    Tracking the movement of underground contaminants is vital to protecting public health and the environment worldwide. Scientific efforts using field tracer techniques to solve contaminant migration problems are rapidly evolving to fill critical information gaps and provide confirmation of laboratory data and numerical models. Various chemical tracers are being used to formulate and evaluate alternative conceptual hydrogeologic modelssemi; namely, to constrain hydraulic properties of geologic systems, identify sources of groundwater, flow paths, and rates, and determine mechanisms that affect contaminant transport. Naturally occurring elements and environmental isotopes from atmospheric and underground nuclear testing can make excellent tracers. In addition, characterizing sites of future waste disposal, such as the potential high-level nuclear waste repository at Yucca Mountain, requires new and innovative techniques like injecting surrogate tracers that simulate potential contaminants and shed light on mechanisms that could control future contaminant migration.

  6. Hydrogeology and quality of ground water in Orange County, Florida

    USGS Publications Warehouse

    Adamski, James C.; German, Edward R.

    2004-01-01

    Ground water is the main source of water supply in central Florida and is critical for aquatic habitats and human consumption. To provide a better understanding for the conservation, development, and management of the water resources of Orange County, Florida, a study of the hydrogeologic framework, water budget, and ground-water quality characteristics was conducted from 1998 through 2002. The study also included extensive analyses of the surface-water resources, published as a separate report. An increase in population from about 264,000 in 1960 to 896,000 in 2000 and subsequent urban growth throughout this region has been accompanied by a substantial increase in water use. Total ground-water use in Orange County increased from about 82 million gallons per day in 1965 to about 287 million gallons per day in 2000. The hydrogeology of Orange County consists of three major hydrogeologic units: the surficial aquifer system, the intermediate confining unit, and the Floridan aquifer system. Data were compiled from 634 sites to construct hydrogeologic maps and sections of Orange County. Water-level elevations measured in 23 wells tapping the surficial aquifer system ranged from about 10.6 feet in eastern Orange County to 123.8 feet above NGVD 29 in northwestern Orange County from March 2000 through September 2001. Water levels also were measured in 14 wells tapping the Upper Floridan aquifer. Water levels fluctuate over time from seasonal and annual variations in rainfall; however, water levels in a number of wells tapping the Upper Floridan aquifer have declined over time. Withdrawal of ground water from the aquifers by pumping probably is causing the declines because the average annual precipitation rate has not changed substantially in central Florida since the 1930s, although yearly rates can vary. A generalized water budget was computed for Orange County from 1991 to 2000. Average rates for the 10-year period for the following budget components were computed based on reported measurements or estimates: precipitation was 53 inches per year (in/yr), runoff was 11 in/yr, spring discharge was 2 in/yr, and net lateral subsurface outflow and exported water was 1 in/yr. Evapotranspiration was 39 in/yr, which was calculated as the residual of the water-budget analysis, assuming changes in storage were negligible. Water-quality samples were collected from April 1999 through May 2001 from a total of 26 wells tapping the surficial aquifer system, 1 well tapping the intermediate confining unit, 24 wells tapping the Upper Floridan aquifer, 2 springs issuing from the Upper Floridan aquifer, and 8 wells tapping the Lower Floridan aquifer. These data were supplemented with existing water-quality data collected by the U.S. Geological Survey and St. Johns River Water Management District. Concentrations of total dissolved solids, sulfate, and chloride in samples from the surficial aquifer system generally were low. Concentrations of nitrate were higher in samples from the surficial aquifer system than in samples from the Upper Floridan or Lower Floridan aquifers, probably as a result of agricultural and residential land use. Water type throughout most of the Upper Floridan and Lower Floridan aquifers was calcium or calcium-magnesium bicarbonate, probably as a result of dissolution of the carbonate rocks. Water type in both the surficial and Floridan aquifer systems in eastern Orange County is sodium chloride. Concentrations of total dissolved solids, sulfate, and chloride in the aquifers increase toward eastern Orange County. Data from 16 of 24 wells in eastern Orange County with long-term water-quality records indicated distinct increases in concentrations of chloride over time. The increases probably are related to withdrawal of ground water at the Cocoa well field, causing an upwelling of deeper, more saline water. The most commonly detected trace elements were aluminum, barium, boron, iron, manganese, and strontium. In addition, arse

  7. Hydrogeology and water quality of the Leetown area, West Virginia

    USGS Publications Warehouse

    Kozar, Mark D.; McCoy, Kurt J.; Weary, David J.; Field, Malcolm S.; Pierce, Herbert A.; Schill, William Bane; Young, John A.

    2008-01-01

    The U.S. Geological Survey’s Leetown Science Center and the co-located U.S. Department of Agriculture’s National Center for Cool and Cold Water Aquaculture both depend on large volumes of cold clean ground water to support research operations at their facilities. Currently, ground-water demands are provided by three springs and two standby production wells used to augment supplies during periods of low spring flow. Future expansion of research operations at the Leetown Science Center is dependent on assessing the availability and quality of water to the facilities and in locating prospective sites for additional wells to augment existing water supplies. The hydrogeology of the Leetown area, West Virginia, is a structurally complex karst aquifer. Although the aquifer is a karst system, it is not typical of most highly cavernous karst systems, but is dominated by broad areas of fractured rock drained by a relatively small number of solution conduits. Characterization of the aquifer by use of fluorometric tracer tests, a common approach in most karst terranes, therefore only partly defines the hydrogeologic setting of the area. In order to fully assess the hydrogeology and water quality in the vicinity of Leetown, a multi-disciplinary approach that included both fractured rock and karst research components was needed. The U.S. Geological Survey developed this multi-disciplinary research effort to include geologic, hydrologic, geophysical, geographic, water-quality, and microbiological investigations in order to fully characterize the hydrogeology and water quality of the Leetown area, West Virginia. Detailed geologic and karst mapping provided the framework on which hydrologic investigations were based. Fracture trace and lineament analysis helped locate potential water-bearing fractures and guided installation of monitoring wells. Monitoring wells were drilled for borehole geophysical surveys, water-quality sampling, water-level measurements, and aquifer tests to characterize the quality of water and the hydraulic properties of the aquifer. Surface geophysical surveys provided a 3-dimensional view of bedrock resistivity in order to assess geologic and lithologic controls on ground-water flow. Borehole geophysical surveys were conducted in monitoring wells to assess the storage and movement of water in subsurface fractures. Numerous single-well, multi-well, and straddle packer aquifer tests and step-drawdown tests were conducted to define the hydraulic properties of the aquifer and to assess the role of bedrock fractures and solution conduits in the flow of ground water. Water samples collected from wells and springs were analyzed to assess the current quality of ground water and provide a baseline for future assessment. Microbiological sampling of wells for indicator bacteria and human and animal DNA provided an analysis of agricultural and suburban development impacts on ground-water quality. Light detection and ranging (LiDAR) data were analyzed to develop digital elevation models (DEMs) for assessing sinkhole distribution, to provide elevation data for development of a ground-water flow model, and to assess the distribution of major fractures and faults in the Leetown area. The flow of ground water in the study area is controlled by lithology and geologic structure. Bedrock, especially low permeability units such as the shale Martinsburg Formation and the Conococheague Limestone, act as barriers to water flowing down gradient and across bedding. This retardation of cross-strike flow is especially pronounced in the Leetown area, where bedding typically dips at steep angles. Highly permeable fault and fracture zones that disrupt the rocks in cross-strike directions provide avenues through which ground water can flow laterally across or through strata of low primary permeability. Significant strike parallel thrust faults and cross-strike faults typically coincide with larger solution conduits and act as drains for the more pervasive network of interconnected diffuse fractures. Results of borehole geophysical surveys in

  8. Calibration of the hydrogeological model of the Baltic Artesian Basin

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

    Let us consider the calibration issue for the Baltic Artesian Basin (BAB) which is a complex hydrogeological system in the southeastern Baltic with surface area close to 0.5 million square kilometers. The model of the geological structure contains 42 layers including aquifers and aquitards. The age of sediments varies from Cambrian up to the Quaternary deposits. The finite element method model was developed for the calculation of the steady state three-dimensional groundwater flow with free surface. No-flow boundary conditions were applied on the rock bottom and the side boundaries of BAB, while simple hydrological model is applied on the surface. The level of the lakes, rivers and the sea is fixed as constant hydraulic head. Constant mean value of 70 mm/year was assumed as an infiltration flux elsewhere and adjusted during the automatic calibration process. Averaged long-term water extraction was applied at the water supply wells. The calibration of the hydrogeological model is one of the most important steps during the model development. The knowledge about the parameters of the modeled system is often insufficient, especially for the large regional models, and a lack of geometric and hydraulic conductivity data is typical. The quasi-Newton optimization method L-BFGS-B is used for the calibration of the BAB model. Model is calibrated on the available water level measurements in monitoring wells and level measurements in boreholes during their installation. As the available data is not uniformly distributed over the covered area, weight coefficient is assigned to each borehole in order not to overestimate the clusters of boreholes. The year 2000 is chosen as the reference year for the present time scenario and the data from surrounding years are also taken into account but with smaller weighting coefficients. The objective function to be minimized by the calibration process is the weighted sum of squared differences between observed and modeled piezometric heads. The parameters of the calibration are the horizontal and vertical hydraulic conductivities of the hydrogeological layers, which are assumed uniform throughout the whole individual layer. The initial values of conductivities are taken from the available field pumping test measurements or based on the lithology of individual hydrogeological layers. The allowed variation range (multiplicative coefficient applied to respective initial parameter value) of conductivities for all layers and of infiltration rate is from 0.01 to 100 times. The minimization of objective function converges in several hundreds of iterations and the mean squared difference in one layer is 7 m. The ratio between the horizontal and vertical conductivity is kept fixed in each optimization run and the effect of different ratios on objective function is shown. The influence of initial values of hydraulic conductivities on the objective function is analyzed. The calibration results are validated using different data sets for calibration and validation. Acknowledgement The present work has been funded by the European Social Fund project "Establishment of interdisciplinary scientist group and modelling system for groundwater research" (Project Nr. 2009/0212/1DP/1.1.1.2.0/09/APIA/VIAA/060)

  9. Hydrogeological and hydrometeorological precursors of Ashkhabad catastrophic earthquake

    NASA Astrophysics Data System (ADS)

    Milkis, M. R.

    1984-05-01

    Retrospective analysis of variations of ground water table, ground water temperature, soil temperature, air temperature, precipitation, air humidity, and discharge of springs reveals that the Ashkhabad earthquake of 1948 occurred against a background of considerable deviations of a number of hydrometeorological and hydrogeological characteristics in the Ashkhabad region. It is difficult to judge whether meteorological factors exerted an influence on the development of the strong earthquake or whether their anomalous regime was a result of heating of the medium over the focus of the future earthquake. Considerable changes in temperature, ground water level and some hydrometeorological elements in the short period of time providing the strong earthquake merit particular attention. Even the relatively rough measurements of ground water parameters used in the analysis indicate a considerable variation during the period of earthquake preparation and the possibility of their use for detecting the precursors of strong seismic processes.

  10. Inversion and Experimental Methods for Tomographic Investigations in Hydrogeology

    NASA Astrophysics Data System (ADS)

    Leven, C.; Schwede, R. L.; Doro, K. O.; Sanchez-Leon, E. E.; Cirpka, O. A.

    2014-12-01

    The spatial variability of hydraulic conductivity K highly influences flow and solute transport in the subsurface. The estimation of the spatial distribution of K in heterogeneous aquifers with an adequate resolution and support scale is therefore one of the major challenges in hydrogeology and still seems to be unsolved. Even though direct measurements of K with modern methods reveal the distribution with typically high vertical resolutions, they still are scarce and local. Therefore, K is mostly inferred from measurements of quantities depending on K, such as hydraulic heads monitored during hydraulic tests and tracer test data. Conventional approaches, such as the type-curve approach for pumping tests, fail in estimating the spatial distribution of K, since they are based on the assumption of homogeneity. Even if data from multi-well pumping tests are analyzed, they always will yield different effective parameters. In contrast, tomographic techniques originally derived for geophysical surveying can be transferred to hydraulic applications and are much better suitable to derive K distributions. In this presentation, we will show results of the project "Tomographic Methods in Hydrogeology" in which we focused on the development of geostatistical methods for the inversion of tomographic data sets of different types (hydraulic testing, heat and ERT-monitoring of salt tracer tests) and the development and improvement of such experimental techniques. Based on selected examples we will present our developments related to the joint geostatistical inversion of tomographic data sets, its efficient parallelization, and its application to a 3D-inversion of tomographic thermal tracer tests. Related to the acquisition of tomographic data sets, we discuss different aspects of the field application of hydraulic tomography, the development of tracer-tomographic methods using heat as tracer, and efficient salt-tracer techniques with a ERT-based salt-tracer monitoring.

  11. Hydrogeologic characterization of an arid zone Radioactive Waste Management Site

    SciTech Connect

    Ginanni, J.M.; O`Neill, L.J.; Hammermeister, D.P.; Blout, D.O.; Dozier, B.L.; Sully, M.J.; Johnejack, K.R.; Emer, D.F.; Tyler, S.W.

    1994-06-01

    An in-depth subsurface site characterization and monitoring program for the soil water migration pathway has been planned, implemented, and completed to satisfy data requirements for a waiver from groundwater monitoring, for an exemption from liner leachate collections systems, and for different regulatory driven performance assessments. A traditional scientific approach has been taken to focus characterization and monitoring efforts. This involved developing a conceptual model of the hydrogeologic system and defining and testing hypotheses about this model. Specific hypotheses tested included: that the system was hydrologically heterogenous and anisotropic, and that recharge was very low or negligible. Mineralogical, physical, and hydrologic data collected to test hypotheses has shown the hydrologic system to be remarkably homogenous and isotropic rather than heterogenous and anisotropic. Both hydrodynamic and environmental tracer approaches for estimating recharge have led to the conclusion that recharge from the Area 5 RWMS is not occurring in the upper region of the vadose zone, and that recharge at depth is extremely small or negligible. This demonstration of ``no migration of hazardous constituents to the water table satisfies a key requirement for both the groundwater monitoring waiver and the exemption from liner leachate collection systems. Data obtained from testing hypotheses concerning the soil water migration pathway have been used to refine the conceptual model of the hydrogeologic system of the site. These data suggest that the soil gas and atmospheric air pathways may be more important for transporting contaminants to the accessible environment than the soil water pathway. New hypotheses have been developed about these pathways, and characterization and monitoring activities designed to collect data to test these hypotheses.

  12. Geographic information system data sets of hydrogeologic conditions in Pequea and Mill Creek watersheds, Pennsylvania; Part II, Hydrogeologic interpretations

    USGS Publications Warehouse

    Low, Dennis J.; Chichester, Douglas C.; Char, Stephen J.

    1995-01-01

    This report describes Geographic Information System data sets of ground-water levels, unsaturated-zone thickness, and regolith thickness in the Pequea and Mill Creek watersheds, a 210-square-mile area in Lancaster and Chester Counties, Pa. The data sets, which represent hydrogeologic interpretations, were developed by the use of ARC/INFO software during 1990-93 by the U.S. Geological Survey, in cooperation with the Pennsylvania Department of Environmental Resources. The U.S. Environmental Protection Agency proposes to use these interpretive data sets, and those from other sources, to aid in the assessment of ground-water vulnerability to pesticides in the Pequea and Mill Creek watersheds.

  13. Hydrogeologic framework of the Johns Creek subbasin and vicinity, Mason County, Washington

    USGS Publications Warehouse

    Welch, Wendy B.; Savoca, Mark E.

    2011-01-01

    This report describes the hydrogeologic framework of the groundwater-flow system in the Johns Creek subbasin and vicinity. The study area covers 97 square miles in southeastern Mason County, Washington, and includes the Johns Creek subbasin, which drains an area of about 11 square miles. The study area extends beyond the Johns Creek subbasin to include major hydrologic features that could be used as regional groundwater-flow model boundaries. The subbasin is underlain by a thick sequence of unconsolidated Quaternary glacial and interglacial deposits, which overlie Tertiary igneous and sedimentary bedrock units. Geologic units were grouped into eight hydrogeologic units consisting of aquifers, confining units, undifferentiated deposits, and an underlying bedrock unit. A surficial hydrogeologic map was developed and used with lithologic information from 200 drillers' logs to construct 4 hydrogeologic sections, and unit extent and thickness maps.

  14. Introduction to Hydrogeology: GLY-4822 Meeting time: 12:00-12:50 M, W, F

    E-print Network

    Sukop, Mike

    Introduction to Hydrogeology: GLY-4822 Meeting time: 12:00-12:50 M, W, F Meeting location: Green of groundwater flow, determination of aquifer properties, geologic factors influencing groundwater flow

  15. Hydrogeological characterization of the South Oyster Bacterial Transport Site using geophysical data

    E-print Network

    Chen, Jinsong

    Hydrogeological characterization of the South Oyster Bacterial Transport Site using geophysical a field-scale bacterial transport study within an uncontaminated sandy Pleistocene aquifer near Oyster Oyster, Virginia. The study is part of the Natural and Accelerated Bioremediation Research (NABIR

  16. A hydrogeologic map of the Death Valley region, Nevada, and California, developed using GIS techniques

    SciTech Connect

    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.

  17. A Hydrogeologic Map of the Death Valley Region, Nevada and California, Developed Using GIS Techniques

    USGS Publications Warehouse

    Faunt, Claudia C.; D'Agnese, Frank A.; Turner, A. Keith

    1997-01-01

    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 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.

  18. Sandia National Laboratories site-wide hydrogeologic characterization project calendar year 1992 annual report

    SciTech Connect

    Crowson, D.; Gibson, J.D.; Haase, C.S.; Holt, R.; Hyndman, D.; Krumhansl, J.; Lauffer, F.; McCord, J.P.; McCord, J.T.; Neel, D.

    1993-10-01

    The Sandia National Laboratories, New Mexico (SNL/NM) Site-Wide Hydrogeologic Characterization (SWHC) project has been implemented as part of the SNL/NM Environmental Restoration (ER) Program to develop the regional hydrogeologic framework and baseline for the approximately 100 mi of Kirtland Air Force Base (KAFB) and adjacent withdrawn public lands upon which SNL/NM has performed research and development activities. Additionally, the SWHC project will investigate and characterize generic hydrogeologic issues associated with the 172 ER sites owned by SNL/NM across its facilities on KAFB. As called for in the Hazardous and Solid Waste Amendments (HSWA) to the Resource Conservation and Recovery Act (RCRA) Part B permit agreement between the U.S. Environmental Protection Agency (EPA) as the permitter and the U.S. Department of Energy (DOE) and SNL/NM as the permittees, an annual report is to be prepared by the SWHC project team. This document serves two primary purposes: (1) to identify and describe the conceptual framework for the hydrogeologic system underlying SNL/NM and (2) to describe characterization activities undertaken in the preceding year that add to our understanding (reduce our uncertainties) regarding the conceptual and quantitative hydrogeologic framework. This SWHC project annual report focuses primarily on purpose 1, providing a summary description of the current {open_quotes}state of knowledge{close_quotes} of the Sandia National Laboratories/Kirtland Air Force Base (SNL/KAFB) hydrogeologic setting.

  19. West Siberian basin hydrogeology - regional framework for contaminant migration from injected wastes

    SciTech Connect

    Foley, M.G.

    1994-05-01

    Nuclear fuel cycle activities of the former Soviet Union (FSU) have resulted in massive contamination of the environment in western Siberia. We are developing three-dimensional numerical models of the hydrogeology and potential contaminant migration in the West Siberian Basin. Our long-term goal at Pacific Northwest Laboratory is to help determine future environmental and human impacts given the releases that have occurred to date and the current waste management practices. In FY 1993, our objectives were to (1) refine and implement the hydrogeologic conceptual models of the regional hydrogeology of western Siberia developed in FY 1992 and develop the detailed, spatially registered digital geologic and hydrologic databases to test them, (2) calibrate the computer implementation of the conceptual models developed in FY 1992, and (3) develop general geologic and hydrologic information and preliminary hydrogeologic conceptual models relevant to the more detailed models of contaminated site hydrogeology. Calibration studies of the regional hydrogeologic computer model suggest that most precipitation entering the ground-water system moves in the near-surface part of the system and discharges to surface waters relatively near its point of infiltration. This means that wastes discharged to the surface and near-surface may not be isolated as well as previously thought, since the wastes may be carried to the surface by gradually rising ground waters.

  20. Hydrogeologic Modeling at the Sylvania Corning FUSRAP Site - 13419

    SciTech Connect

    Ewy, Ann; Heim, Kenneth J.; McGonigal, Sean T.; Talimcioglu, Nazmi M.

    2013-07-01

    A comparative groundwater hydrogeologic modeling analysis is presented herein to simulate potential contaminant migration pathways in a sole source aquifer in Nassau County, Long Island, New York. The source of contamination is related to historical operations at the Sylvania Corning Plant ('Site'), a 9.49- acre facility located at 70, 100 and 140 Cantiague Rock Road, Town of Oyster Bay in the westernmost portion of Hicksville, Long Island. The Site had historically been utilized as a nuclear materials manufacturing facility (e.g., cores, slug, and fuel elements) for reactors used in both research and electric power generation in early 1950's until late 1960's. The Site is contaminated with various volatile organic and inorganic compounds, as well as radionuclides. The major contaminants of concern at the Site are tetrachloroethene (PCE), trichloroethene (TCE), nickel, uranium, and thorium. These compounds are present in soil and groundwater underlying the Site and have migrated off-site. The Site is currently being investigated as part of the Formerly Utilized Sites Remedial Action Program (FUSRAP). The main objective of the current study is to simulate the complex hydrogeologic features in the region, such as numerous current and historic production well fields; large, localized recharge basins; and, multiple aquifers, and to assess potential contaminant migration pathways originating from the Site. For this purpose, the focus of attention was given to the underlying Magothy formation, which has been impacted by the contaminants of concern. This aquifer provides more than 90% of potable water supply in the region. Nassau and Suffolk Counties jointly developed a three-dimensional regional groundwater flow model to help understand the factors affecting groundwater flow regime in the region, to determine adequate water supply for public consumption, to investigate salt water intrusion in localized areas, to evaluate the impacts of regional pumping activity, and to better understand the contaminant transport and fate mechanisms through the underlying aquifers. This regional model, developed for the N.Y. State Department of Environmental Conservation (NYSDEC) by Camp Dresser and McKee (CDM), uses the finite element model DYNFLOW developed by CDM, Cambridge, Massachusetts. The coarseness of the regional model, however, could not adequately capture the hydrogeologic heterogeneity of the aquifer. Specifically, the regional model did not adequately capture the interbedded nature of the Magothy aquifer and, as such, simulated particles tended to track down-gradient from the Site in relatively straight lines while the movement of groundwater in such a heterogeneous aquifer is expected to proceed along a more tortuous path. This paper presents a qualitative comparison of site-specific groundwater flow modeling results with results obtained from the regional model. In order to assess the potential contaminant migration pathways, a particle tracking method was employed. Available site-specific and regional hydraulic conductivity data measured in-situ with respect to depth and location were incorporated into the T-PROG module in GMS model to define statistical variation to better represent the actual stratigraphy and layer heterogeneity. The groundwater flow characteristics in the Magothy aquifer were simulated with the stochastic hydraulic conductivity variation as opposed to constant values as employed in the regional model. Contaminant sources and their exact locations have been fully delineated at the Site during the Remedial Investigation (RI) phase of the project. Contaminant migration pathways originating from these source locations at the Site are qualitatively traced within the sole source aquifer utilizing particles introduced at source locations. Contaminant transport mechanism modeled in the current study is based on pure advection (i.e., plug flow) and mechanical dispersion while molecular diffusion effects are neglected due to relatively high groundwater velocities encountered in the aquifer. In addition, fate of contam

  1. Hydrogeologic framework of fractured sedimentary rock, Newark Basin, New Jersey

    USGS Publications Warehouse

    Lacombe, Pierre J.; Burton, William C.

    2010-01-01

    The hydrogeologic framework of fractured sedimentary bedrock at the former Naval Air Warfare Center (NAWC), Trenton, New Jersey, a trichloroethylene (TCE)-contaminated site in the Newark Basin, is developed using an understanding of the geologic history of the strata, gamma-ray logs, and rock cores. NAWC is the newest field research site established as part of the U.S. Geological Survey Toxic Substances Hydrology Program, Department of Defense (DoD) Strategic Environmental Research and Development Program, and DoD Environmental Security Technology Certification Program to investigate contaminant remediation in fractured rock. Sedimentary bedrock at the NAWC research site comprises the Skunk Hollow, Byram, and Ewing Creek Members of the Lockatong Formation and Raven Rock Member of the Stockton Formation. Muds of the Lockatong Formation that were deposited in Van Houten cycles during the Triassic have lithified to form the bedrock that is typical of much of the Newark Basin. Four lithotypes formed from the sediments include black, carbon-rich laminated mudstone, dark-gray laminated mudstone, light-gray massive mudstone, and red massive mudstone. Diagenesis, tectonic compression, off-loading, and weathering have altered the rocks to give some strata greater hydraulic conductivity than other strata. Each stratum in the Lockatong Formation is 0.3 to 8 m thick, strikes N65 degrees E, and dips 25 degrees to 70 degrees NW. The black, carbon-rich laminated mudstone tends to fracture easily, has a relatively high hydraulic conductivity and is associated with high natural gamma-ray count rates. The dark-gray laminated mudstone is less fractured and has a lower hydraulic conductivity than the black carbon-rich laminated mudstone. The light-gray and the red massive mudstones are highly indurated and tend to have the least fractures and a low hydraulic conductivity. The differences in gamma-ray count rates for different mudstones allow gamma-ray logs to be used to correlate and delineate the lithostratigraphy from multiple wells. Gamma-ray logs and rock cores were correlated to develop a 13-layer gamma-ray stratigraphy and 41-layer lithostratigraphy throughout the fractured sedimentary rock research site. Detailed hydrogeologic framework shows that black carbon-rich laminated mudstones are the most hydraulically conductive. Water-quality and aquifer-test data indicate that groundwater flow is greatest and TCE contamination is highest in the black, carbon- and clay-rich laminated mudstones. Large-scale groundwater flow at the NAWC research site can be modeled as highly anisotropic with the highest component of permeability occurring along bedding planes.

  2. Analysis of Hydrogeologic Conceptual Model and Parameter Uncertainty

    SciTech Connect

    Meyer, Philip D.; Nicholson, Thomas J.; Mishra, Srikanta

    2003-06-24

    A systematic methodology for assessing hydrogeologic conceptual model, parameter, and scenario uncertainties is being developed to support technical reviews of environmental assessments related to decommissioning of nuclear facilities. The first major task being undertaken is to produce a coupled parameter and conceptual model uncertainty assessment methodology. This task is based on previous studies that have primarily dealt individually with these two types of uncertainties. Conceptual model uncertainty analysis is based on the existence of alternative conceptual models that are generated using a set of clearly stated guidelines targeted at the needs of NRC staff. Parameter uncertainty analysis makes use of generic site characterization data as well as site-specific characterization and monitoring data to evaluate parameter uncertainty in each of the alternative conceptual models. Propagation of parameter uncertainty will be carried out through implementation of a general stochastic model of groundwater flow and transport in the saturated and unsaturated zones. Evaluation of prediction uncertainty will make use of Bayesian model averaging and visualization of model results. The goal of this study is to develop a practical tool to quantify uncertainties in the conceptual model and parameters identified in performance assessments.

  3. Hydrogeological-Geophysical Methods for Subsurface Site Characterization - Final Report

    SciTech Connect

    Rubin, Yoram

    2001-01-01

    The goal of this research project is to increase water savings and show better ecological control of natural vegetation by developing hydrogeological-geophysical methods for characterizing the permeability and content of water in soil. The ground penetrating radar (GPR) tool was developed and used as the surface geophysical method for monitoring water content. Initial results using the tool suggest that surface GPR is a viable technique for obtaining precision volumetric water content profile estimates, and that laboratory-derived petrophysical relationships could be applied to field-scale GPR data. A field-scale bacterial transport study was conducted within an uncontaminated sandy Pleistocene aquifer to evaluate the importance of heterogeneity in controlling the transport of bacteria. Geochemical, hydrological, geological, and geophysical data were collected to characterize the site prior to and after chemical and bacterial injection experiments. Study results shows that, even within the fairly uniform shallow marine deposits of the narrow channel focus area, heterogeneity existed that influenced the chemical tracer transport over lateral distances of a few meters and vertical distances of less than a half meter. The interpretation of data suggest that the incorporation of geophysical data with limited hydrological data may provide valuable information about the stratigraphy, log conductivity values, and the spatial correlation structure of log conductivity, which have traditionally been obtainable only by performing extensive and intrusive hydrological sampling.

  4. The hydrogeology of the Gombe subcatchment, Benue Valley, Nigeria

    NASA Astrophysics Data System (ADS)

    Iyioriobhe, S. E.; Ako, B. D.

    The area of study, which is about 90 km 2, is underlain by five major stratigraphic units of Paleocene to Cretaceous age except for the Precambrian Basement Complex inlier which forms about 2.7% of the rocks present. Results of our investigation show that the Kerri-Kerri Formation is of aquifer type material but dry in the surveyed area. The Gombe Formation with its high percentages of silts is slightly permeable, whilst the Pindiga and Yolde Formations are essentially aquicludes, although the latter has scattered water-bearing horizons. Chemical analyses of borehole water indicate good quality water despite the differences in depth of sampling. Two groups of water emerged—sodium bicarbonate rich and sodium bicarbonate deficient types. Results of isotope hydrology suggest that the sodium deficient type water has similar characteristics to the waters from the middle zone aquifer of the Chad basin and deep aquifer of the Sokoto basin. The highest computer transmissivity value ( T) of 432 m 2/d and storage coefficient ( S) of 2.3 × 10 -3 in the subcatchment were for the Bima Formation. The Bima Formation is thus the best aquifer in the subcatchment. Since the available data show that the aquifer of the Bima Formation is gradually being over-developed, and the observed characteristics of a few boreholes in the Pindiga and Yolde Formations are encouraging, a detailed hydrogeological assessment of the other Formations in the Gombe subcatchment is recommended.

  5. The deep hydrogeologic flow system underlying the Oak Ridge Reservation

    SciTech Connect

    Nativ, R.; Hunley, A.E.

    1993-07-01

    The deep hydrogeologic system underlying the Oak Ridge Reservation contains some areas contaminated with radionuclides, heavy metals, nitrates, and organic compounds. The groundwater at that depth is saline and has previously been considered stagnant. On the basis of existing and newly collected data, the nature of flow of the saline groundwater and its potential discharge into shallow, freshwater systems was assessed. Data used for this purpose included (1) spatial and temporal pressures and hydraulic heads measured in the deep system, (2) hydraulic parameters of the formations in question, (3) spatial temperature variations, and (4) spatial and temporal chemical and isotopic composition of the saline groundwater. In addition, chemical analyses of brine in adjacent areas in Tennessee, Kentucky, Ohio, Pennsylvania, and West Virginia were compared with the deep water underlying the reservation to help assess the origin of the brine. Preliminary conclusions suggest that the saline water contained at depth is old but not isolated (in terms of recharge and discharge) from the overlying active and freshwater-bearing units. The confined water (along with dissolved solutes) moves along open fractures (or man-made shortcuts) at relatively high velocity into adjacent, more permeable units. Groundwater volumes involved in this flow probably are small.

  6. Hydrogeologic characterization of a fractured granitic rock aquifer, Raymond, California

    SciTech Connect

    Cohen, A.J.B.

    1993-10-01

    The hydrogeologic properties of a shallow, fractured granitic rock aquifer in the foothills of the Sierra Nevada, California were investigated via the analysis of borehole geophysical logs and pumping tests. The drawdowns produced during these tests are not indicative of any simple conceptual aquifer model, and borehole logs show that the granite is intensely fractured. These observations are suggestive of a complex fracture-flow geometry which is extremely difficult to decipher. However, through the measurement of orientations of individual subsurface fractures from acoustic televiewer logs, and correlation between particular fractures and electrical resistivity and thermal-pulse flowmeter logs, it was found that the aquifer is, in general, comprised of two subhorizontal and nearly parallel zones of unloading fractures. Downhole flowmeter measurements taken in several wells provide further evidence for the inferred dual-layer structure of the aquifer, as well as yield quantitative measures of the contribution of flow from each zone. Analysis of drawdowns in pumped wells reveals that there are zones of relatively high transmissivity immediately around them. It was found that these properties, as well as a nearby zone of lower transmissivity, can account for their observed drawdowns. A numerical model was constructed to test whether these major heterogeneities could also account for the drawdowns in observation wells. This stepwise analysis of both the geophysical and hydrological data resulted in the formulation of a conceptual model of the aquifer which is consistent with observations, and which can account for its behavior when subjected to pumping.

  7. Hydrogeologic controls on water quality at a university dairy farm

    NASA Astrophysics Data System (ADS)

    McKay, L. D.; Hunter, R. W.; Lee, J.

    2010-12-01

    Dairy farms typically produce large quantities of manure and other waste products which are often stored or treated in lagoons and then applied to local fields as fertilizer. Contamination of nearby streams by dairy farm wastes through surface runnoff, drainage tile discharge, direct release of wastes or inundation of waste storage facilities during seasonal flooding have long been recognized as major environmental concerns. However, much less attention has been paid to fate and transport of dairy wastes in the subsurface and their potential impact on water quality in aquifers or in groundwater discharge to streams. One of the challenges in evaluating the environmental impact of dairy operations is that there are relatively few field research sites where all of the potential pathways for waterborne transport of dairy wastes are monitored and quantititatively evaluated. There are even fewer sites where extensive baseline water quality monitoring programs were established prior to operation of the dairy. This is essential to distinguish between environmental impacts from dairy operations and other nearby sources, such as beef production and human sewage from septic fields. This talk describes the development of a an integrated hydrogeologic/hydrologic site assessment and groundwater/surface water quality monitoring program at the University of Tennessee - Little River Dairy Farm, located near Townsend, TN. The dairy is currently under construction and the first cows are expected to arrive in late 2010. Hydrologic/hydrogeologic investigations of streams and groundwater at the site have been underway for more than 3 years, and these are expected to provide background data for assessing impacts of dairy wastes and for testing the effectiveness of different management practises. The lower half of the ~180 ha site consists of low-relief fields used for row crops, which are underlain by 4 - 8 m of alluvial deposits (mainly interbedded silt and fine-grained sands) on top of by black shale or limestone. Several active sinkholes are present in the portion of the fields underlain by limestone. The fields are bounded on two sides by the Little River, a popular recreational river, and on the third side by Ellejoy Creek, which is on the state’s 303(d) list for impairment by nutrients, sediment and fecal microorganisms, which are derived from upstream agricultural and rural residential development. These fields will be fertilized with treated dairy wastes and are the main area of concern for offsite migration of contaminants through groundwater, drainage ditches and (eventually) a tile drain system. A secondary area of concern is the dairy waste treatment pond which is located, along with the dairy barns, on the upland portion of the site, which is underlain by 1-2 m of clay-rich residual soils developed on fractured shale bedrock. Long term water quality monitoring of runnoff, streams, drainage ditches and groundwater is planned, with the intent of measuring environmental impact of dairy operations and testing the effectiveness of different management practises.

  8. Hydrogeologic Characterization of the U-3bl Collapse Zone

    SciTech Connect

    NSTec Geotechnical Services

    2006-09-01

    The U-3bl collapse crater was formed by an underground nuclear test in August 1962. This crater and the adjoining U-3ax crater were subsequently developed and used as a bulk low-level radioactive waste disposal cell (U-3ax/bl), which is part of the Area 3 Radioactive Waste Management Site at the Nevada Test Site (NTS). Various investigations have been conducted to assess the hydrogeologic characteristics and properties in the vicinity of the U-3ax/bl waste disposal cell. This report presents data from one of these investigations, conducted in 1996. Also included in this report is a review of pertinent nuclear testing records, which shows that the testing operations and hydrogeologic setting of the U-3ax/bl site were typical for the period and location of testing. Borehole U-3bl-D2 is a 45-degree-angle hole drilled from the edge of the crater under the waste cell to intercept the U-3bl collapse zone, the disturbed alluvium between the crater (surface collapse sink) and the nuclear test cavity. A casing-advance system with an air percussion hammer was used to drill the borehole, and air was used as the drilling fluid. Properties of the U-3bl crater collapse zone were determined from cores collected within the interval, 42.1 to 96.6 meters (138 to 317 feet) below the ground surface. Selected core samples were analyzed for particle density, particle size, bulk density, water retention, hydraulic conductivity, water content, water potential, chloride, carbonate, stable isotopes, and tritium. Physical and hydraulic properties were typical of alluvial valley sediments at the NTS. No visual evidence of preferential pathways for water transport was observed in the core samples. Soil parameters showed no trends with depth. Volumetric water content values ranged from 0.08 to 0.20 cubic meters per cubic meter, and tended to increase with depth. Water-retention relations were typical for soils of similar texture. Water potentials ranged from -1.9 MegaPascals at a depth of 42.10 meters (138 feet) to -0.4 MegaPascals at 94.58 meters (310 feet), generally increasing with depth. Relationships between hydraulic conductivity and water content were typical of sandy soil, with hydraulic conductivity decreasing rapidly as the soil dried. Variability of hydraulic conductivity reflected layering and showed no trend with depth. Stable isotope compositions were typical of water that had infiltrated during cooler past climate conditions. Uniformity of concentrations versus depth indicated that evaporation was not occurring at the sampled interval. Tritium concentrations in pore water ranged from 2.68 x10{sup 3} to 1.22 x 10{sup 4} picoCuries per liter, which are greater than expected from atmospheric deposition of tritium, but not at a level to raise environmental concerns. The tritium is most likely a product of nuclear testing.

  9. Hydrogeologic characterization of the Modesto Area, San Joaquin Valley, California

    USGS Publications Warehouse

    Burow, Karen R.; Shelton, Jennifer L.; Hevesi, Joseph A.; Weissmann, Gary S.

    2004-01-01

    Hydrogeologic characterization was done to develop an understanding of the hydrogeologic setting near Modesto by maximizing the use of existing data and building on previous work in the region. A substantial amount of new lithologic and hydrologic data are available that allow a more complete and updated characterization of the aquifer system. In this report, geologic units are described, a database of well characteristics and lithology is developed and used to update the regional stratigraphy, a water budget is estimated for water year 2000, a three-dimensional spatial correlation map of aquifer texture is created, and recommendations for future data collection are summarized. The general physiography of the study area is reflected in the soils. The oldest soils, which have low permeability, exist in terrace deposits, in the interfan areas between the Stanislaus, Tuolumne, and Merced Rivers, at the distal end of the fans, and along the San Joaquin River floodplain. The youngest soils have high permeability and generally have been forming on the recently deposited alluvium along the major stream channels. Geologic materials exposed or penetrated by wells in the Modesto area range from pre-Cretaceous rocks to recent alluvium; however, water-bearing materials are mostly Late Tertiary and Quaternary in age. A database containing information from more than 3,500 drillers'logs was constructed to organize information on well characteristics and subsurface lithology in the study area. The database was used in conjunction with a limited number of geophysical logs and county soil maps to define the stratigraphic framework of the study area. Sequences of red paleosols were identified in the database and used as stratigraphic boundaries. Associated with these paleosols are very coarse grained incised valley-fill deposits. Some geophysical well logs and other sparse well information suggest the presence of one of these incised valley-fill deposits along and adjacent to the Tuolumne River east of Modesto, a feature that may have important implications for ground-water flow and transport in the region. Although extensive work has been done by earlier investigators to define the structure of the Modesto area aquifer system, this report has resulted in some modification to the lateral extent of the Corcoran Clay and the regional dip of the Mehrten Formation. Well logs in the database indicating the presence of the Corcoran Clay were used to revise the eastern extent of the Corcoran Clay, which lies approximately parallel to the axis of valley. The Mehrten Formation is distinguished in the well-log database by its characteristic black sands consisting of predominantly andesitic fragments. Black sands in wells listed in the database indicate that the formation may lie as shallow as 120 meters (400 feet) below land surface under Modesto, approximately 90 meters (300 feet) shallower than previously thought. The alluvial aquifer system in the Modesto area comprises an unconfined to semiconfined aquifer above and east of the Corcoran Clay confining unit and a confined aquifer beneath the Corcoran Clay. The unconfined aquifer is composed of alluvial sediments of the Modesto, Riverbank, and upper Turlock Lake formations. The unconfined aquifer east of the Corcoran Clay becomes semiconfined with depth due to the numerous discontinuous clay lenses and extensive paleosols throughout the aquifer thickness. The confined aquifer is composed primarily of alluvial sediments of the Turlock Lake and upper Mehrten Formations, extending from beneath the Corcoran Clay to the base of fresh water. Ground water in the unconfined to semiconfined aquifer flows to the west and southwest. The primary source of present-day recharge is percolating excess irrigation water. The primary ground-water discharge is extensive ground-water pumping in the unconfined to semiconfined aquifer, imposing a significant component of vertical flo

  10. A Conceptual Hydrogeologic Model of the Vicinity of DUSEL Homestake

    NASA Astrophysics Data System (ADS)

    Murdoch, L. C.; Germanovich, L. N.; Boutt, D. F.; Kieft, T. L.; Wang, H. F.; Onstott, T. C.

    2009-12-01

    The Deep Underground Science and Engineering Laboratory (DUSEL) is a research facility planned to occupy the workings of the former Homestake gold mine in the northern Black Hills, South Dakota. The hydrogeology was of minor importance to locating and recovering gold ore, so it was overlooked during mining and is relatively unknown. This knowledge gap hinders planning of the Deep EcoHydrology Experiment at DUSEL and motivated the work described here. The conceptual hydrogeologic model is characterized by permeability that is assumed to be anisotropic and controlled by regional foliation, which strikes approximately N20W and dips steeply to the NE. Permeability is on the order of 0.1 mD in fresh rock, but increases to roughly 100 mD at shallow depths. The permeability distribution is assumed to result from unloading of the foliated rock, and a simple model of stress-dependence explains the permeability distribution and suggests that the more permeable zone is on the order of ~100 m thick. A stream hydrograph from Whitetail Creek (station 06436156) was analyzed to estimate recharge flux and the result indicates an average value of approximately 5 x 10-9 m/s. A numerical model of the vicinity of the mine was developed by representing the mine workings as a dual- porosity inclusion embedded in a single-porosity, anisotropic material. The extent of the dual-porosity medium was advanced downward based on the mining records and the hydraulic head within the material representing the mine workings was adjusted to represent filling and draining of the workings. The results suggest that the groundwater is characterized by a shallow flow system of distributed recharge that mostly discharges to nearby streams. The mine itself acts like a large sink that moves downward and to the southeast during mining, and then is controlled by variations in pumping rate once the mine reaches its greatest depth. The deep flow system consists of (i) a zone of relatively rapid flow from the ground surface to the mine workings overlying the southern part of the mine, and (ii) a much larger ellipsoidal zone extending up to several km from the workings where water has been removed from storage. Maximum downward fluxes in the deep system are less than the recharge rate because flow occurs at unit head gradient and the permeability of the rock is relatively low (~0.1 mD). This explains why dewatering has negligible impact on overlying streams and suggests that the regional water table remains within the shallow flow system. The results also indicate that water on the southern side of the mine is probably quite young (<~1 yr) and influenced by recent recharge, whereas water on the north side is much older and affected by removal from storage in deep pore space. The observed dewatering rate at the mine can be explained without requiring additional inflow from a large open pit or other surficial workings.

  11. A new hydrogeologic model to predict anthropogenic uplift of Venice

    NASA Astrophysics Data System (ADS)

    Teatini, P.; Castelletto, N.; Ferronato, M.; Gambolati, G.; Tosi, L.

    2011-12-01

    Recent numerical studies based on a simplified lithostratigraphy of the Venice subsurface suggest that the city may be raised by pumping seawater into deep aquifers through 12 wells located on a 10 km diameter circle. Using an updated 3-D reconstruction of the Quaternary deposits, developed very recently from about 1050 km of multichannel seismic profiles and eight exploration wells, along with a more accurate representation of the injection boreholes, novel finite-element predictions are performed. The new model simulates the lithostratigraphy of the lagoon subsurface and allows for a reliable assessment of the water volumes injected into the geologic formations based on the actual bottom hole overpressure that can vary both in space and time. Pumping occurs into two Pleistocene sequences that are originated from the Alps and Apennine sedimentation and terminate just south and north of Venice, respectively, and the shelf portion of a Pliocene sequence that is rather continuous below the central lagoon with arenite layers to depths as much as 1000 m below mean sea level. With a proper tuning of the injection pressure the new hydrogeologic model allows for a prediction of a quite uniform 25-30 cm uplift over 10 years after the inception of injection. The gradient of the vertical displacement ?z does not exceed 5 × 10-5 and 1 × 10-5 in the whole lagoon and Venice, respectively, i.e., well below the most conservative bound recommended for the safety of the structures. If ad hoc calibrated injection overpressures are implemented in each single well, ?z may be reduced to as much as 0.1 × 10-5 throughout the city.

  12. Hydrogeology of an alkaline fly ash landfill in Eastern Iowa

    SciTech Connect

    Spencer, L.L.S.; Drake, L.D.

    1987-09-01

    The hydrogeology and chemical quality of the shallow ground-water regime at a coal fly ash landfill was investigated near Montpelier, Iowa. An embankment dam retains the two-hectare deposit of silt-sized alkaline coal fly ash in an upland ravine. The fly ash landfill was operated between 1964-1973 and was subsequently capped with a thin loess layer and seeded to pasture. The ash is underlain by loess, over clay-rich till, over sandstone. Ground water now saturates the lower one-half of the ash. Nineteen shallow monitoring wells were installed around and within the landfill. Sampling in 1983-1984 was conducted for water levels, temperature, pH, alkalinity, specific conductance, calcium (Ca/sup 2+/), magnesium (Mg/sup 2+/), sodium (Na/sup +/), potassium (K/sup +/), sulfate (SO/sub 4//sup 2-/), chloride (Cl/sup -/), arsenic (As), and selenium (See). Calculated ion balances for 30 analyses had an error of less than 4%. Native loess-derived ground water of a calcium bicarbonate type enters the landfill, and then shifts to a calcium sulfate type. A distinct leachate plume presently extends at least 46 meters downgradient from the landfill, passing under and through the dam, then discharging into a small pond. SO/sub 4//sup 2-/ and Se concentrations in the plume exceed EPA drinking water standards, and trace As was detected. Although ground-water pH increased after entering the landfill, bicarbonate alkalinity declined. Results of equilibrium solubility calculations suggest that this condition evolved from calcite supersaturation within the landfill, precipitating calcium carbonate. Dissolution of calcium and magnesium oxides on the glassy fly ash spheres sustains the highly alkaline leachate strength.

  13. Research of Hydro-Geological Precursors of Earthquakes in Armenia

    NASA Astrophysics Data System (ADS)

    Pashayan, R.

    2007-12-01

    The observations of hydro-geological regime of underground waters in observed boreholes began in Armenia in 1986. Now these work is concentrated in National Seismic Service. For a long time observations are carried out studying several parameters (debit, temperature, chemical and gas composition) in several deposits of carbon mineral waters of Armenia. The interpretation of materials shows that that a number of strong and medium-strength earthquakes are accompanied by anomal changes in the level of underground waters. Regarding mineral waters, in connection with earthquakes some parameters are immediately changed: debit, temperature, chemical and gas composition. The study of hydrogeodynamic characteristics of precursors specify that the quantity of registered hydrogeodynamic precursors decreases with the increase of epicentrical distance. The majority of precursors is registered at the distance of 200 km from epicenter. There is a tendency of gradual increase of time and amplitude of a precursor of an earthquake depending on the rise of magnitude and epicentral distance. The behaviour of hydrogeodynamic precursors depends on the angle between the faults, to which this or that borehole reaches; with increase of this angle the deformation in the zone of the fault during the preparation of earthquakes is stronger, than in terms of small angles. 1. S1 2. Earthquake processes, Precursors and Forecasts 3. Garni Geophysical Observatory of the National Academy of Sciences of Armenia, 375019, Yerevan, Republic of Armenia, email: hakhleon@sci.am 4. O 5. 10808801 6. Artavazd Payment Type: select 'Purchase Order' PO Number: AGU WAIVER Billing Address: Enter Your Institution City: Enter Your City Country Code: Enter Your Country Name: Enter Your Name Phone: Enter Your Telephone Number

  14. Hydrogeology and potential water-resource targets in Mauritania, Africa

    NASA Astrophysics Data System (ADS)

    Horton, J. D.; Friedel, M. J.; Finn, C.

    2012-12-01

    A hydrogeologic study is conducted in support of mineral-resource assessment activities in Mauritania, Africa. Airborne magnetic depth estimates reveal two primary ground-water basins: the porous Continental Terminal coastal system (fill deposits); and the interior, fractured interior Taoudeni Basin system (carbonate, clastic, metasedimentary, and metavolcanic rocks). In the Continental Terminal basin, there is uniform vertical recharge and localized discharge that is coincident with ground-water pumping at Nouakchott. This pumping center induces eastward flow of ground water from the Atlantic Ocean resulting in a salinity gradient that diminishes quality over 100 km. Ground water also flows southward into the basin from Western Sahara. By contrast, an interbasin exchange occurs as fresh ground-water flows westward from the Taoudeni basin. In the Taoudeni basin, zones of local recharge occur in three areas: northwest at the edge of the Réguibat Shield, at the city of Tidjikdja, and to the south overlying Tillites. Ground water also flows across country boundaries: northward into Western Sahara and westward into Mali. At the southern country boundary, the Sengal River serves as both a source and sink of fresh ground water to these two basins. Using a geographical information system, 13 hydrostratigraphic units are identified based on lateral extent and distinct hydrologic properties for future groundwater model development. Combining this information with drilling productivity, water quality, and geophysical interpretations (fracturing and absence of subsurface dikes) identified 3 potential water-resource development targets: sedimentary rocks of Cambrian-Ordovician age, sedimentary rocks of Neoproterozoic age, and carbonate rocks of middle Mesoproterozoic age.

  15. Hydrogeologic framework of the Boise Aquifer system, southwestern Idaho

    SciTech Connect

    Squires, E.; Wood, S.H. ); Osiensky, J.L. )

    1993-04-01

    The City of Boise relies upon the underlying groundwater resource (38,000 acre-feet/year) for 90% of its public water-supply. Basin-fill sediments which comprise this system of aquifers are divisible into five distinct hydrogeologic settings which differ on the basis of sediment type, geophysical log character, and hydraulic properties. A large buried alluvial-fan/fan-delta complex (the Boise Fan) occupies the eastern head of the basin. Down-valley gradations in sediment type show a general increase in unit thickness and sediment color more typically gray; reflecting transition to the lake environment of deposition. Basinward (northwestward), the ancient fan materials grade into lake/fan transitional sediments which grade to predominantly lake sediment which grade to gray mudstones and fine sand layers of the deep lake environment. The depth to which drinking-water aquifers extend is limited by an underlying sequence of relatively impermeable volcanic rocks. Specific capacities of efficient wells, 400--1,200 feet deep and open to 80--100 feet of sand are highest in the lake/fan transition and the lacustrine aquifers of central Boise, lowest for the Boise Fan and intermediate for the deep artesian sand aquifers of west Boise. As a result of screen and filter-pack design based upon attention to sampling drill cuttings, sieve analysis of sands, and geophysical log location of aquifers, efficiency and productivity of new wells has been greatly increased. Groundwater recharge to the deeper aquifers is via permeable surface gravels. Increased groundwater withdrawals have possibly accelerated recharge by increasing vertical hydraulic gradients. Overbored wells with continuous surface-to-depth gravel packs, wells open to multiple aquifers, and improperly abandoned wells with deteriorating casing are also conduits for polluted shallow groundwater to enter the deeper aquifers.

  16. Hydrogeologic Controls on Lake Level at Mountain Lake, Virginia

    NASA Astrophysics Data System (ADS)

    Roningen, J. M.; Burbey, T. J.

    2011-12-01

    Mountain Lake in Giles County, Virginia has a documented history of severe natural lake-level changes involving groundwater seepage that extend over the past 4200 years. Featured in the 1986 movie Dirty Dancing, the natural lake dried up completely in September 2008 and levels have not yet recovered. A hydrogeologic investigation was undertaken in an effort to determine the factors influencing lake level changes. A daily water balance, dipole-dipole electrical resistivity surveying, well logging and chemical sampling have shed light on: 1) the influence of a fault not previously discussed in literature regarding the lake, 2) the seasonal response to precipitation of a forested first-order drainage system in fractured rock, and 3) the possibility of flow pathways related to karst features. Geologic controls on lake level were investigated using several techniques. Geophysical surveys using dipole-dipole resistivity located possible subsurface flowpaths both to and from the lake. Well logs, lineament analysis, and joint sampling were used to assess structural controls on lake hydrology. Major ions were sampled at wells, springs, streams, and the lake to evaluate possible mixing of different sources of water in the lake. Groundwater levels were monitored for correlation to lake levels, rainfall events, and possible seismic effects. The hydrology of the lake was quantified with a water balance on a daily time step. Results from the water balance indicate steady net drainage and significant recharge when vegetation is dormant, particularly during rain-on-snow melt events. The resistivity survey reveals discrete areas that represent flow pathways from the lake, as well as flowpaths to springs upgradient of the lake located in the vicinity of the fault. The survey also suggests that some flowpaths may originate outside of the topographic watershed of the lake. Chemical evidence indicates karst may underlie the lakebed. Historical data suggest that artificial intervention to mitigate seepage would be required for lake level recovery in the near future.

  17. David L. Parkhurst as the recipient of the 2012 O.E. Meinzer Award of the Hydrogeology Division of the Geological Society of America

    USGS Publications Warehouse

    Glynn, Pierre D.

    2012-01-01

    Describes the impact of USGS scientist David Parkhurst's influential contributions to the fields of aqueous geochemistry and hydrogeology. Parkhurst is the recipient of the 2012 O.E. Meinzer award of the Geological Society of America's Hydrogeology Division.

  18. AGU Chapman Conference Hydrogeologic Processes: Building and Testing Atomistic- to Basin-Scale Models

    SciTech Connect

    Weaver, B.

    1994-12-31

    This report presents details of the Chapman Conference given on June 6--9, 1994 in Lincoln, New Hampshire. This conference covered the scale of processes involved in coupled hydrogeologic mass transport and a concept of modeling and testing from the atomistic- to the basin- scale. Other topics include; the testing of fundamental atomic level parameterizations in the laboratory and field studies of fluid flow and mass transport and the next generation of hydrogeologic models. Individual papers from this conference are processed separately for the database.

  19. Field trip guidebook to the hydrogeology of the Rock-Fox River basin of Southeastern Wisconsin

    USGS Publications Warehouse

    Holt, C. L. R., Jr.; Cotter, R.D.; Green, J.H.; Olcott, P.G.

    1970-01-01

    On this trip we will examine some hydrogeologic characteristics of glacial features and emphasize ground-water management within the Rock-Fox River basin. Field stops will include the hydrogeology of a classical glacial terrane--the Kettle moraine--and the management of ground-water resources for industrial, municipal, agricultural, and fish-culture purposes. Descriptions of the geology, soils, water availability and characteristics, water quality, water use, and water problems within the basin are given in the accompanying U.S. Geological Survey Hydrologic Atlas (HA-360). This atlas is a product of the cooperative program of University Extension--the University of Wisconsin Geological and Natural History Survey.

  20. Final Technical Report - Integrated Hydrogeophysical and Hydrogeologic Driven Parameter Upscaling for Dual-Domain Transport Modeling

    SciTech Connect

    Shafer, John M

    2012-11-05

    The three major components of this research were: 1. Application of minimally invasive, cost effective hydrogeophysical techniques (surface and borehole), to generate fine scale (~1m or less) 3D estimates of subsurface heterogeneity. Heterogeneity is defined as spatial variability in hydraulic conductivity and/or hydrolithologic zones. 2. Integration of the fine scale characterization of hydrogeologic parameters with the hydrogeologic facies to upscale the finer scale assessment of heterogeneity to field scale. 3. Determination of the relationship between dual-domain parameters and practical characterization data.

  1. Integrated Research Methods for Applied Urban Hydrogeology of Karst Sites

    NASA Astrophysics Data System (ADS)

    Epting, J.; Romanov, D. K.; Kaufmann, G.; Huggenberger, P.

    2008-12-01

    Integrated and adaptive surface- and groundwater monitoring and management in urban areas require innovative process-oriented approaches. To accomplish this, it is necessary to develop and combine interdisciplinary instruments that facilitate adequately quantifying cumulative effects on groundwater flow regimes. While the characterization and modeling of flow in heterogeneous and fractured media has been investigated intensively, there are no well-developed long-term hydrogeological research sites for gypsum karst. Considering that infrastructures in karst regions, particularly in gypsum, are prone to subsidence, severe problems can arise in urban areas. In the 1880's, a river dam was constructed on gypsum-containing rock, Southeast of Basel, Switzerland. Over the last 30 years, subsidence of the dam and an adjacent highway has been observed. Surface water infiltrates upstream of the dam, circulates in the gravel deposits and in the weathered bedrock around and beneath the dam and exfiltrates downstream into the river. These processes enhance karstification processes in the soluble units of the gypsum. As a result an extended weathering zone within the bedrock and the development of preferential flow paths within voids and conduits can be observed. To prevent further subsidence, construction measures were conducted in two major project phases in 2006 and 2007. The highway was supported by a large number of pillars embedded in the non- weathered rock and by a sealing pile wall, to prevent infiltrating river water circulating around the dam and beneath the foundation of the highway. To safeguard surface and subsurface water resources during the construction measures, an extensive observation network was set up. Protection schemes and geotechnical investigations that are necessary for engineering projects often provide "windows of opportunity", bearing the possibility to change perceptions concerning the sustainable development of water resources and coordinate future measures. Theories describing the evolution of karst systems are mainly based on conceptual models. Although these models are based on fundamental and well established physical and chemical principles that allow studying important processes from initial small scale fracture networks to the mature karst, systems for monitoring the evolution of karst phenomena are rare. Integrated process-oriented investigation methods are presented, comprising the combination of multiple data sources (lithostratigraphic information of boreholes, extensive groundwater monitoring, dye tracer tests, geophysics) with high-resolution numerical groundwater modeling and model simulations of karstification below the dam. Subsequently, different scenarios evaluated the future development of the groundwater flow regime, the karstification processes as well as possible remediation measures. The approach presented assists in optimizing investigation methods, including measurement and monitoring technologies with predictive character for similar subsidence problems within karst environments in urban areas.

  2. Application of the self-potential method in hydrogeology

    NASA Astrophysics Data System (ADS)

    Moore, Jeffrey Ralston

    The self-potential (SP) method is a passive electrical tool that measures naturally occurring voltages created by fluid flow in earth materials. SP monitoring has proven to be a fast and inexpensive means for evaluating subsurface hydrology. This dissertation presents the results of three studies, demonstrating innovative use of the SP method for describing both historical and new hydrogeologic scenarios. The cumulative result encourages application of SP monitoring in a variety of situations, and demonstrates the unique ability of the SP method to describe the physical processes controlling subsurface fluid flow. Three topics were investigated by means of SP monitoring: hydraulic fracturing of low-permeability intact rock, liquid CO2 flow through rock in support of carbon sequestration research, and seepage characterization at a remote moraine dam. In the case of hydraulic fracturing, SP observations responded to permeability variations prior to fracturing caused by dilatancy of microcracks at high pore pressure. An asymmetric spatial SP response was observed as injectate moved into aligned dilatant zones during pressurization, which in most cases revealed the impending crack geometry. SP measurements described the direction of crack propagation after initial fracturing due to strong anisotropic flow through the new fracture zone. During liquid CO 2 injection into reservoir rock, differences in the magnitude of the SP coupling coefficient (Cc) were observed for various stages of a CO 2 flood. The Cc was found to decrease by an order of magnitude as CO 2 replaced mobile water in the rock porosity, and the variation of the Cc during CO2 and water mixing was characterized. These results allow mapping of the various phase boundaries present during liquid CO 2 injection, and may contribute to the success of carbon sequestration. Finally, a preliminary description of the hydraulic regime at a remote moraine dam was obtained through analysis of SP and accompanying electrical resistivity measurements. The inferred hydrologic information was then used to comment on the stability of the dam with respect to seepage erosion. SP data revealed that seepage is concentrated in the area adjacent to suspected fine sediment output, suggesting that seepage erosion likely occurred at some time during the life of the dam.

  3. Hydrogeology of a Transboundary Sandstone Aquifer, Quebec - New York

    NASA Astrophysics Data System (ADS)

    Nastev, M.; Lamontagne, C.; Morin, R.; Williams, J.; Lavigne, M.; Croteau, A.; Tremblay, T.; Godin, R.; Dagenais, M.; Rouleau, A.

    2005-12-01

    The Potsdam sandstone aquifer of Cambrian age straddles southern Quebec and northern New York in a region known for its abundant and good quality groundwater, a resource that recently has been coveted by several bottling companies. The potential conflicts and concerns of the mainly rural and groundwater dependent population about the possible overuse of this resource has led the Quebec Ministry of Environment, Geological Survey of Canada and the U. S. Geological Survey to jointly carry out a transboundary hydrogeological study of the Potsdam sandstone aquifer. The Potsdam sandstone aquifer consists of a lower unit of arkose and conglomerate and an upper unit of well-cemented quartz arenite. The thickness of the regional aquifer ranges from nil at the base of Adirondacks to more than 500 m near the St. Lawrence River. Glacial till, littoral sand and gravel, and marine silt and clay discontinuously overlie the aquifer. The aquifer's water budget is characterized by low rates of surface runoff and high rates of infiltration and sub-surface runoff. Major recharge areas are present at higher altitudes near and to the south of the border. Strong downward hydraulic gradients in these areas result in cascading water and water-level depths of more than 30 m in deep wells. Bedding in the Potsdam sandstone is gently dipping with fractures along sub-horizontal bedding planes forming major flow conduits. Bedrock folds and faults, mainly developed by east-west compression during the Appalachian orogenies, locally complicates aquifer geometry and groundwater flow. Hydraulic tests (pump, slug, flowmeter and straddle packer) indicate similar horizontal transmissivities in the lower and upper aquifer units. However, differences in lithology and structure of the aquifer units impose some apparent differences in hydraulic properties and groundwater flow patterns. In the lower unit, regional flow appears to be sustained by a limited number of laterally extensive bedding-plane fractures. During aquifer tests, significant drawdown was observed in observation wells at distances of more than a kilometer from pumped wells, whereas nearby nested piezometers screened in different bedding planes showed markedly less drawdown. Groundwater users that exploit the same permeable fracture zones are thus highly interdependent and vulnerable to their respective pumping rates. On the other hand, the more densely fractured upper unit apparently has more dispersed groundwater flow. Numerical modeling of the regional groundwater flow substantiates these differences. In order to match measured hydraulic heads, the calibrated vertical anisotropy of the lower unit was in average 100 times higher than that of the upper unit. Simulated capture areas of production wells display elongated forms commonly crossing the Quebec-New York border. Simulated scenarios are the first step towards the joint management of the groundwater resources.

  4. Aquifer Hydrogeologic Layer Zonation at the Hanford Site

    SciTech Connect

    Savelieva-Trofimova, Elena A.; Kanevski, Mikhail; timonin, v.; Pozdnukhov, A.; Murray, Christopher J.; Scheibe, Timothy D.; Xie, YuLong; Thorne, Paul D.; Cole, Charles R.

    2003-09-10

    Sedimentary aquifer layers are characterized by spatial variability of hydraulic properties. Nevertheless, zones with similar values of hydraulic parameters (parameter zones) can be distinguished. This parameter zonation approach is an alternative to the analysis of spatial variation of the continuous hydraulic parameters. The parameter zonation approach is primarily motivated by the lack of measurements that would be needed for direct spatial modeling of the hydraulic properties. The current work is devoted to the problem of zonation of the Hanford formation, the uppermost sedimentary aquifer unit (U1) included in hydrogeologic models at the Hanford site. U1 is characterized by 5 zones with different hydraulic properties. Each sampled location is ascribed to a parameter zone by an expert. This initial classification is accompanied by a measure of quality (also indicated by an expert) that addresses the level of classification confidence. In the current study, the coneptual zonation map developed by an expert geologist was used as an a priori model. The parameter zonation problem was formulated as a multiclass classification task. Different geostatistical and machine learning algorithms were adapted and applied to solve this problem, including: indicator kriging, conditional simulations, neural networks of different architectures, and support vector machines. All methods were trained using additional soft information based on expert estimates. Regularization methods were used to overcome possible overfitting. The zonation problem was complicated because there were few samples for some zones (classes) and by the spatial non-stationarity of the data. Special approaches were developed to overcome these complications. The comparison of different methods was performed using qualitative and quantitative statistical methods and image analysis. We examined the correspondence of the results with the geologically based interpretation, including the reproduction of the spatial orientation of the different classes and the spatial correlation structure of the classes. The uncertainty of the classification task was examined using both probabilistic interpretation of the estimators and by examining the results of a set of stochastic realizations. Characterization of the classification uncertainty is the main advantage of the proposed methods.

  5. Evaluation of Hydrochemical and Hydrogeological Characteristics of Riverbank Filtration Aquifer

    NASA Astrophysics Data System (ADS)

    Ko, K.; Suk, H.

    2009-12-01

    The riverbank filtration is a feasible method to secure potable water resources where surface water cannot be directly provided. Bank filtrate water has been recently recognized as an alternative water resource around Nakdong River area in South Korea. The high manganese and iron, which are mainly produced from microbial reduction of aquifer, are frequently observed problems in bank filtrated water and the causes of them have been studied by restricted researchers. To understand the source and occurrence of manganese and iron in bank filtration water, we examined the hydrochemical and isotopic characteristics of water and the features of aquifer sediments which are collected from two bank filtration application area, Ddan Island and Jeungsan-ri. Most of waters collected from Ddan island have Ca-(Cl+SO4) type and the variation of water chemistry are mainly induced by anions such as bicarbonate and nitrate that are sensitive to the redox condition of aquifer. Nitrate is not detected in deep (>20m) water with low dissolved oxygen (<2 mg/L) but is very high (max. 120 mg/L), presumably indicating the input of surface agricultural green house, in shallow (<10m) water. The bicarbonate in the Ddan Island aquifer can be increased by the biodegradation of organic matters and the dissolution of shellfishes which are included in aquifer sediments. The high carbon isotope values of dissolved inorganic carbon indicate that the main process of bicarbonate production is the microbial degradation of organic matter in the aquifer. The oxygen and hydrogen isotopic values in water are plotted at the lower region below the line of local meteoric water line (LMWL). The spatial distribution of redox sensitive components such as iron, manganese, sulfate, nitrate, and bicarbonate implicate the redox processes of the Ddan Island aquifer. We also investigated the hydrogeologic structure, bank filtrate quality analysis and modified sequential analysis for Ddan Island aquifer at Nakdong River. The research results showed the minimum three times of repetitive change of sedimentation environment. Thick clay layers in the aquifer are preventing the inflow of river water to the production wells. In addition, the aquifer underneath the clay layer is under reducing condition, which might cause the high concentration of reduced iron and manganese. Manganese in the sediments was in the form of easily reducible and exchangeable phase but iron were present dominantly in the form of reducible and carbonate phase from the modified sequential analysis. This indicates the different reactivity of manganese and iron for redox state. From the above results, manganese was extracted under weakly reduced condition but iron was extracted strong reducing condition.

  6. Combined Estimation of Hydrogeologic Conceptual Model and Parameter Uncertainty

    SciTech Connect

    Meyer, Philip D.; Ye, Ming; Neuman, Shlomo P.; Cantrell, Kirk J.

    2004-03-01

    The objective of the research described in this report is the development and application of a methodology for comprehensively assessing the hydrogeologic uncertainties involved in dose assessment, including uncertainties associated with conceptual models, parameters, and scenarios. This report describes and applies a statistical method to quantitatively estimate the combined uncertainty in model predictions arising from conceptual model and parameter uncertainties. The method relies on model averaging to combine the predictions of a set of alternative models. Implementation is driven by the available data. When there is minimal site-specific data the method can be carried out with prior parameter estimates based on generic data and subjective prior model probabilities. For sites with observations of system behavior (and optionally data characterizing model parameters), the method uses model calibration to update the prior parameter estimates and model probabilities based on the correspondence between model predictions and site observations. The set of model alternatives can contain both simplified and complex models, with the requirement that all models be based on the same set of data. The method was applied to the geostatistical modeling of air permeability at a fractured rock site. Seven alternative variogram models of log air permeability were considered to represent data from single-hole pneumatic injection tests in six boreholes at the site. Unbiased maximum likelihood estimates of variogram and drift parameters were obtained for each model. Standard information criteria provided an ambiguous ranking of the models, which would not justify selecting one of them and discarding all others as is commonly done in practice. Instead, some of the models were eliminated based on their negligibly small updated probabilities and the rest were used to project the measured log permeabilities by kriging onto a rock volume containing the six boreholes. These four projections, and associated kriging variances, were averaged using the posterior model probabilities as weights. Finally, cross-validation was conducted by eliminating from consideration all data from one borehole at a time, repeating the above process, and comparing the predictive capability of the model-averaged result with that of each individual model. Using two quantitative measures of comparison, the model-averaged result was superior to any individual geostatistical model of log permeability considered.

  7. HYDROGEOLOGIC SETTINGS OF EARTHEN WASTE STORAGE STRUCTURES ASSOCIATED WITH CONFINED ANIMAL FEEDING OPERATIONS IN IOWA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty-four permitted earthen waste storage structures (EWSS) were investigated to characterize their hydrogeologic setting using digital soils data, digital elevation data, and oblique aerial photographs. Nearly 18% of the sites were constructed over alluvial aquifers and flood plains. More than h...

  8. INVESTIGATION OF HYDROGEOLOGIC MAPPING TO DELINEATE PROTECTION ZONES AROUND SPRINGS: REPORT OF TWO CASE STUDIES

    EPA Science Inventory

    Methods commonly used to delineate protection zones for water-supply wells are often not directly applicable for springs. This investigation focuses on the use of hydrogeologic mapping methods to identify physical and hydrologic features that control ground-water flow to springs...

  9. ASSESSING THE HYDROGEOLOGIC CLASSIFICATION SYSTEM IN MID-ATLANTIC COASTAL PLAIN STREAMS USING BENTHIC MACROINVERTEBRATES

    EPA Science Inventory

    Assessing classification systems that describe natural variation across regions is an important first step for developing indicators. We evaluated a hydrogeologic framework for first order streams in the mid-Atlantic Coastal Plain as part of the LIPS-MACS (Landscape Indicators f...

  10. Inventory and Review of Existing PRISM Hydrogeologic Data for the Islamic Republic of Mauritania, Africa

    USGS Publications Warehouse

    Friedel, Michael J.

    2008-01-01

    The USGS entered into an agreement with the Mauritania Ministry of Mines and Industry to inventory and review the quality of information collected as part of the Project for Strengthening of the Institutions in the Mining Sector (PRISM). Whereas the PRISM program collected geophysical, geochemical, geological, satellite, and hydrogeologic information, this report focuses on an inventory and review of available hydrogeologic data provided to the USGS in multiple folders, files, and formats. Most of the information pertained to the hydrogeologic setting and the water budget of evaporation, evapotranspiration, and precipitation in the Choum-Zouerate area in northwestern Mauritania, and the country of Mauritania itself. Other information about the quantity and quality of groundwater was found in the relational Access database. In its present form, the limited hydrogeologic information was not amenable to conducting water balance, geostatistical, and localized numerical modeling studies in support of mineral exploration and development. Suggestions are provided to remedy many of the data's shortcomings, such as performing quality assurance on all SIPPE2 data tables and sending questionnaires to appropriate agencies, mining and other companies to populate the database with additional meteorology, hydrology, and groundwater data.

  11. HYDROGEOLOGIC CONTROLS ON NITRATE TRANSPORT IN A SMALL AGRICULTURAL CATCHMENT, IOWA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effects of subsurface lithology on nitrate loss in stream riparian zones are recognized but little attention has been focused on similar processes occurring in upland agricultural settings. In this paper, we evaluated hydrogeologic controls on nitrate transport processes occurring in a small 7.6 ha ...

  12. MODELLING AND QUANTIFYING THE HYDROGEOLOGICAL EFFECTS IN THE ADVANCE OF A TUNNEL EXCAVATION BY TBM

    E-print Network

    Politècnica de Catalunya, Universitat

    MODELLING AND QUANTIFYING THE HYDROGEOLOGICAL EFFECTS IN THE ADVANCE OF A TUNNEL EXCAVATION BY TBM with Tunnel Boring Machine (TBM), it is necessary to find a method for predicting where the water inflows TBM (Tunnel Boring Machine). This machine forms a shield for rock with the possibility of working

  13. Linking Physical and Numerical Modelling in Hydrogeology Using Sand Tank Experiments and Comsol Multiphysics

    ERIC Educational Resources Information Center

    Singha, Kamini; Loheide, Steven P., II

    2011-01-01

    Visualising subsurface processes in hydrogeology and building intuition for how these processes are controlled by changes in forcing is hard for many undergraduate students. While numerical modelling is one way to help undergraduate students explore outcomes of multiple scenarios, many codes are not user-friendly with respect to defining domains,…

  14. Hydrogeological modeling of the saline hot springs at the Sea of Galilee, Israel

    E-print Network

    Gvirtzman, Haim

    Hydrogeological modeling of the saline hot springs at the Sea of Galilee, Israel Haim Gvirtzman Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel Grant Garven Department Department of Geography, Bar Ilan University, Ramat Gan, Israel Abstract. Meteoric fresh groundwater from

  15. American hydrogeology at the millennium: An annotated chronology of 100 most influential papers

    USGS Publications Warehouse

    Back, W.; Herman, J.S.

    1997-01-01

    Hydrogeology developed as scientists undertook activities to describe how a groundwater system functions to explain why it is that way, in order to solve practical problems of water supply. This paper demonstrates the evolutionary nature and growth of hydrogeology in the United States on the basis of a selection of one hundred papers that had a significant impact on subsequent activities. We have identified three revolutionary concepts that resulted directly from this evolutionary understanding and have selected papers that demonstrate important consequences. These three concepts are 1) that the mathematical expression for heat flow can be paraphrased for groundwater and used in transient flow conditions to determine aquifer characteristics; 2) that the distribution of fluid potential can be formulated in mathematical equations suitable for solution by various analytical techniques; and 3) that chemical thermodynamics can be applied to hydrogeologic systems in order to understand the processes controlling the chemical character of groundwater. One purpose of this paper is to encourage scientists to gain an additional dimension of satisfaction from their work by being aware of the contributions of those who went before them and to see how their own work fits into the current understanding of hydrogeology.

  16. Hydrogeologic Modeling: GLY-5826 Meeting time: T, Th 11-12:15

    E-print Network

    Sukop, Mike

    Syllabus Hydrogeologic Modeling: GLY-5826 Meeting time: T, Th 11-12:15 Meeting location: TBD Course Level: Graduate 5826 Sections: 1 Course Catalogue Description Techniques used in modeling groundwater. MODFLOW 9. Heterogeneous aquifers a. Streamline refraction 10. Inverse Methods a. PEST/Groundwater Vistas

  17. Hydrogeological modelling as a tool for understanding rockslides evolution

    NASA Astrophysics Data System (ADS)

    Crosta, Giovanni B.; De Caro, Mattia; Frattini, Paolo; Volpi, Giorgio

    2015-04-01

    Several case studies of large rockslides have been presented in the literature showing dependence of displacement rate on seasonal and annual changes of external factors (e.g. rainfall, snowmelt, temperature oscillations) or on human actions (e.g. impounding of landslide toe by artificial lakes, toe excavation). The study of rockslide triggering can focus on either the initial failure or the successive reactivations driven by either meteo-climatic events or other perturbations (e.g. seismic, anthropic). A correlation between groundwater level oscillations and slope movements has been observed at many different sites and in very different materials and slope settings. This seasonal dynamic behavior generally shows a delay between perturbation (e.g., groundwater recharge and increase in water table level) and system reaction (e.g., increase in displacement rate). For this reason, groundwater modeling offers the means for assessing the oscillation of groundwater level which is a major input in rockslide and deep-seated gravitational slope deformation modelling, and that could explain both the initial failure event as well the successive reactivation or the continuous slow motion. Using a finite element software (FEFLOW, WASY GmbH) we developed 2D saturated/unsaturated and steady-state/transient groundwater flow models for two case studies for which a suitable dataset is available: the Vajont rockslide (from 1960 to October 9th 1963) and the Mt. de La Saxe rockslide (2009-2012, Aosta valley; Italian Western Alps). The transient models were implemented starting from hydraulic head distributions simulated in the previous steady-state models to investigate the groundwater fluctuation within the two chosen times interval (Vajont: 1960-1963 ; La Saxe: 2009-2012). Time series of infiltration resulting from precipitation, temperature, snowmelt data (La Saxe rockslide) and reservoir level (Vajont rockslide) were applied to the models. The assumptions made during the construction of the models, in particular the partition of the slope in different sectors with different hydraulic conductivities, are coherent with the geological, structural, hydrological and hydrogeological field and laboratory data. The sensitivity analysis shows that the hydraulic conductivity of some slope sectors (e.g. morphostructures, compressed or relaxed slope-toe, basal shear band) strongly influence the water table position and evolution. In transient models, the values of specific storage coefficient play a major control on the amplitude of groundwater level fluctuations, deriving from snowmelt or induced reservoir level rise. The calibrated groundwater flow-models are consistent with groundwater levels measured in the proximity of the piezometers aligned along the sections. The two examples can be considered important for a more advanced understanding of the evolution of rockslides and suggest the required set of data and modelling approaches both for seasonal and long term slope stability analyses. The use of the results of such analyses is reported, for both the case studies, in a companion abstract in session 3.7 where elasto-visco-plastic rheologies have been adopted for the shear band materials to replicate the available displacement time-series.

  18. Using Electrical Resistivity Tomography for Constraining a Hydrogeological Model in a Data Sparse Region

    NASA Astrophysics Data System (ADS)

    Foster, S.; Allen, D. M.

    2013-12-01

    Geological and hydrogeological data are often spatially limited in mountainous regions. In these settings, geophysical techniques can be used to constrain hydrogeological models by providing insight into the hydrostratigraphy and the continuity of units in the subsurface. This study we used electrical resistivity tomography coupled with a priori geological data from residential water wells to improve the accuracy and confidence of a hydrogeological model. The study area is situated within the mountainous Cowichan watershed in British Columbia, Canada. Throughout the watershed, unconsolidated deposits of variable thickness overlie bedrock. Based on available water well information, at high elevation, sediment thickness is on the order of a few metres, but within the valley bottom, sediment thickness can be up to 300 m. The unconsolidated deposits are heterogeneous due to a complex depositional environment that was controlled by glacial advances and recessions, most notably during the Fraser Glaciation. Six electrical resistivity transects of various lengths spanning 135 to 830 metres were conducted in an area of the watershed that is particularly data poor. The electrical resistivity transects were strategically placed, first, to make use of available lithology information from existing water wells in order to constrain the geophysical interpretation, and second, to contribute data to areas that lack subsurface lithological records. Electrical resistivity was measured using a AGI SuperSting R1 system, and data were processed using robust inversion software to identify stark geophysical contacts. The technique successfully delineated zones of conductive and resistive units that have been interpreted as aquitards (clay and till formations), aquifers (water bearing sand and gravel lenses), and bedrock based on dielectric contrast. Available surficial geology and bedrock geology maps, coupled with residential well drilling records, further assisted in mapping the continuity of the hydrogeological units at a larger scale, and the results were digitized and integrated to construct a three dimensional hydrogeological model of the watershed.

  19. Digital Surfaces and Thicknesses of Selected Hydrogeologic Units within the Mississippi Embayment Regional Aquifer Study (MERAS)

    USGS Publications Warehouse

    Hart, Rheannon M.; Clark, Brian R.; Bolyard, Susan E.

    2008-01-01

    Digital surfaces of selected Tertiary and younger age hydrogeologic units within the Mississippi embayment aquifer system were created using more than 2,600 geophysical logs for an area that covers approximately 70,000 square miles and encompasses parts of eight states. The digital surfaces were developed to define and display the hydrogeologic framework for the Mississippi Embayment Regional Aquifer Study (MERAS). The digital surfaces also provide a foundation of the selected hydrogeologic units for development of a steady-state and transient regional ground-water flow model of the Mississippi embayment aquifer system from the top of the Midway confining unit upwards to land surface. The ground-water flow model is under development as part of the U.S. Geological Survey Ground-Water Resources Program. Using a Geographic Information System, nine digital surfaces of the tops of selected hydrogeologic units were created using the Australian National University Digital Elevation Model method as an interpolation scheme. Thickness maps also were constructed using the Geographic Information System by calculating the difference between the altitude of the interpreted base of an overlying unit and the altitude of the interpreted top of an underlying unit. In general, the highest hydrogeologic unit altitudes are located along the eastern edge of the study area in the outcrop, and the lowest altitudes, in general, are located along the southern edge of the study area along the axis of the embayment. The Mississippi River Valley alluvial aquifer and the lower Claiborne aquifer are the thinnest aquifers of importance in the study area; the thickest aquifer of importance is the middle Claiborne aquifer.

  20. Hydrogeological Parameter Estimation Using Low-Field Proton Nuclear Magnetic Resonance: Lessons from the Laboratory

    NASA Astrophysics Data System (ADS)

    Keating, K.; Falzone, S.; Osterman, G. K.; Wallace, D. S.

    2014-12-01

    Geophysical methods can provide a non-invasive method for estimating spatial variability in hydrogeological parameters such as water content, hydraulic conductivity, and matric potential. Proton nuclear magnetic resonance (NMR) is unique amongst geophysical methods in that it is directly sensitive to water, via the initial signal magnitude, and thus provides a robust estimate of water content. In addition, the NMR relaxation time is sensitive to pore geometry, allowing it to be used to predict the hydraulic conductivity and to determine water retention curves. While NMR measurements are considered a mature technology in the petroleum industry, the strength of NMR data for hydrogeophysical studies is still being realized. The major ongoing challenge is to generate a functional mapping of the relationship between pore geometry and relaxation time, while accounting for pore chemistry. In our research, we are developing and refining quantitative petrophysical models that relate NMR parameters to hydrogeological parameters. Here we present laboratory measurements that highlight our recent successes in using NMR measurements to estimate several hydrogeological parameters and overcome the limitations of the standard petrophysical models. We examine these relationships by collecting NMR measurements on synthetic and geologic materials with carefully controlled or quantified pore properties, i.e., pore surface-area-to-volume ratio (S/V), pore size and surface iron concentration, and relate these variables to hydrogeological parameters including water content, hydraulic conductivity, and/or the water retention curve. Our major results include developing a relationship between the NMR relaxation times and water saturation across diverse chemical environments, and showing that for materials with rough surfaces, S/V, and not average pore diameter, is the relevant parameter in the interpretation of NMR data. Despite the many challenges in interpreting the measurements, valuable information about hydrogeological parameters can be obtained from NMR relaxation data, and we conclude by outlining pathways for improving the interpretation of NMR data for hydrogeophysical investigations.

  1. Hydrogeologic Characterization of an Aquitard Using Poroelastic Responses and Near Surface Geophysics

    NASA Astrophysics Data System (ADS)

    Hart, D. J.; Streiff, C. M.

    2014-12-01

    In central Wisconsin, irrigation use has dramatically increased over the last several decades. This increase has given rise to concerns over impacts to surface waters from groundwater pumping. We instrumented an irrigated field and a nearby prairie to assess those impacts and compare hydrogeologic responses. The hydrogeology of the two sites is similar, a layered system of 10 meters of sand over 2 to 3 meters of clay and silt over 30 meters of sand. The clay and silt is a recognized geologic unit, the New Rome Formation. Although the New Rome Formation is found over an area of 160 km2, little is known about its hydrogeologic properties. We used poroelastic responses and near-surface geophysics, in addition to traditional hydrogeologic tools such as pumping tests and sediment characterization, to assess the hydrogeologic parameters of the New Rome and the upper and lower sands. The instrumentation consisted of piezometers in all three layers and pumping wells above and below the New Rome. We observed a head decrease of 1.1 meters across the New Rome. We conducted pumping tests using the wells above and below the New Rome. When pumping from below the New Rome, we observed the Noordbergum effect, a small transitory head increase of 4 cm in the New Rome and 1.5 cm in the shallow piezometer above. The piezometer in the deep sand aquifer showed around 30 cm of drawdown during this pumping. We also conducted a loading test on the New Rome. We backed a truck mounted drill rig over the piezometer and monitored the response. We saw a head increase of 1.3 cm that dissipated in around 3 minutes. These responses were modeling using a coupled poroelastic model. We also collected ground penetrating radar data that can be used to identify the depositional model for the New Rome and the overlying sand aquifer. These results all suggest that the New Rome is behaving like an aquitard at this site with a vertical hydraulic conductivity that varies with depth and location. This new understanding of the hydrogeologic characteristics of a regional aquitard in an area of increased water use is essential for estimating and communicating the impacts of the increased water use. For example, we can better estimate the impacts to surface waters from groundwater pumping for irrigation if we know the role that the New Rome aquitard plays in the regional flow system.

  2. Morphometric analysis with open source software to explore shallow hydrogeological features in Senegal and Guinea

    NASA Astrophysics Data System (ADS)

    Fussi, Fabio; Di Leo, Margherita; Bonomi, Tullia; Di Mauro, Biagio; Fava, Francesco; Fumagalli, Letizia; Hamidou Kane, Cheikh; Faye, Gayane; Niang, Magatte; Wade, Souleye; Hamidou, Barry; Colombo, Roberto

    2015-04-01

    Water represents a vital resource for everyone on this Planet, but, for some populations, the access to potable water is not given for granted. Recently, the interest in low cost technical solutions to improve access to ground water in developing countries, especially for people located in remote areas, has increased. Manual drilling (techniques to drill boreholes for water using human or animal power) is well known and practiced for centuries in many countries and represents a valid alternative to increase water access. Lately, this practice has raised the attention of national governments and international organizations. This technique is applicable only where hydrogeological conditions are suitable, namely in presence of thick layers of unconsolidated sediments and a shallow water table Aim of this study is exploring the potential of morphometric analysis to improve the methodology to identify areas with suitable hydrogeological conditions for manual drilling, supporting the implementation of water supply programs that can have great impact on living condition of the population. The characteristics of shallow geological layers are strongly dependent from geomorphological processes and are usually reflected in the morphological characteristics of landforms. Under these hypotheses, we have been investigating the geo-statistical correlation between several morphometric variables and a set of hydrogeological variables used in the estimation of suitability for manual drilling: thickness of unconsolidated sediments, texture, hydraulic conductivity of shallow aquifer, depth of water table. The morphology of two study areas with different landscape characteristics in Guinea and Senegal has been investigated coupling the Free and Open Source Software GRASS GIS and R. Several morphometric parameters have been extracted from ASTER GDEM digital elevation model, and have been compared with a set of hydrogeological characteristics obtained from semi-automatic analysis of stratigraphic logs from water boreholes. We observed the relationships between the spatial distribution of hydrogeological features and the morphology, applying multivariate statistical analysis. The ultimate goal of this study is to infer hydrogeological information of shallow aquifers, exploiting morphometric parameters (together with other layers of information from existing thematic maps and remote sensing) and to reconstruct the geometry and the characteristic of shallow porous aquifer. This research is part of a larger project financed by NERC (National Environment Research Council, UK) in the framework of the program UPGRO (Unlocking the Potential of Groundwater for the Poors), with the collaboration of different partners from Italy, Senegal and Guinea

  3. Hydrogeology of the gray limestone aquifer in southern Florida

    USGS Publications Warehouse

    Reese, Ronald S.; Cunningham, Kevin J.

    2000-01-01

    Results from 35 new test coreholes and aquifer-test, water-level, and water-quality data were combined with existing hydrogeologic data to define the extent, thickness, hydraulic properties, and degree of confinement of the gray limestone aquifer in southern Florida. This aquifer, previously known to be present only in southeastern Florida (Miami-Dade, Broward, and Palm Beach Counties) below, and to the west of, the Biscayne aquifer, extends over most of central-south Florida, including eastern and central Collier County and southern Hendry County; it is the same as the lower Tamiami aquifer to the north, and it becomes the water-table aquifer and the upper limestone part of the lower Tamiami aquifer to the west. The aquifer generally is composed of gray, shelly, lightly to moderately cemented limestone with abundant shell fragments or carbonate sand, abundant skeletal moldic porosity, and minor quartz sand. The gray limestone aquifer comprises the Ochopee Limestone of the Tamiami Formation, and, in some areas, the uppermost permeable part of an unnamed formation principally composed of quartz sand. Underlying the unnamed formation is the Peace River Formation of the upper Hawthorn Group, the top of which is the base of the surficial aquifer system. Overlying the aquifer and providing confinement in much of the area is the Pinecrest Sand Member of the Tamiami Formation. The thickness of the aquifer is comparatively uniform, generally ranging from 30 to 100 feet. The unnamed formation part of the aquifer is up to 20 feet thick. The Ochopee Limestone accumulated in a carbonate ramp depositional system and contains a heterozoan carbonate-particle association. The principal rock types of the aquifer are pelecypod lime rudstones and floatstones and permeable quartz sands and sandstones. The pore types are mainly intergrain and separate vug (skeletal-moldic) pore spaces. The rock fabric and associated primary and secondary pore spaces combine to form a dual diffuse-carbonate and conduit flow system capable of producing high values of hydraulic conductivity. Transmissivity values of the aquifer are commonly greater than 50,000 feet squared per day to the west of Miami-Dade and Broward Counties. Hydraulic conductivity ranges from about 200 to 12,000 feet per day and generally increases from east to west; an east-to-west shallowing of the depositional profile of the Ochopee Limestone carbonate ramp contributes to this spatial trend. The aquifer contains two areas of high transmissivity, both of which trend northwest-southeast. One area extends through southern Hendry County. The other area extends through eastern Collier County, with a transmissivity as high as 300,000 feet squared per day; in this area, the aquifer is structurally high, the top of the aquifer is close to land surface, and it is unconfined to semiconfined. The confinement of the aquifer is good to the north and east in parts of southern Hendry, Palm Beach, Collier, Broward, and Miami-Dade Counties. In these areas, the upper confining unit approaches or is greater than 50 feet thick, and vertical leakance is less than 1.0 x 10-3 l/day. In most of the study area, the specific conductance in water from the gray limestone aquifer is 1,500 microsiemens per centimeter or less (chloride concentration of about 250 milligrams per liter or less). Areas where specific conductance is greater than 3,000 microsiemens per centimeter are found where there is a low horizontal-head gradient and the upper confining unit is greater than 50 feet thick. An area with specific conductance less than 1,500 microsiemens per centimeter extends from southern Hendry County to the southeast into western Broward County and coincides with an area of high transmissivity. However, much of this area has good confinement. The potentiometric gradient also is to the southeast in much of the area, and this area of low specific conductance is probably caused by a relatively rapid downgradient movement of fres

  4. Hydrogeologic investigation of the Middle San Pedro watershed, southeastern Arizona: a project of the Rural Watershed Initiative

    USGS Publications Warehouse

    Thomas, Blakemore E.

    2006-01-01

    In 2005, the U.S. Geological Survey (USGS) began an investigation of the hydrogeology of the middle San Pedro watershed in cooperation with the Arizona Department of Water Resources (ADWR). This project is part of the Rural Watershed Initiative (RWI), which is a program established by the State of Arizona and managed by the ADWR. The primary objective of this project is to improve the understanding of the hydrogeology of the middle San Pedro watershed.

  5. Characterizing the hydrogeologic framework of the Death Valley region, Southern Nevada and California

    USGS Publications Warehouse

    Faunt, Claudia; D'Agnese, Frank; Downey, Joe S.; Turner, A. Keith

    1993-01-01

    Three-dimensional (3-D) hydrogeologic modeling of the complex geology of the Death Valley region requires the application of a number of Geoscientific Information System (GSIS) techniques. This study, funded by United States Department of Energy as a part of the Yucca Mountain Project, focuses on an area of approximately 100,000 square kilometers (three degrees of latitude by three degrees of longitude) and extends up to ten kilometers in depth. 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. GSIS techniques allow the synthesis of geologic, hydrologic and climatic information gathered from many sources, including satellite imagery and published maps and cross-sections. Construction of a 3-D hydrogeological model is possible with the combined use of software products available from several vendors, including traditional GIS products and sophisticated contouring, interpolation, visualization, and numerical modeling packages.

  6. Hydrogeological characterization of Back Forty area, Albany Research Center, Albany, Oregon

    SciTech Connect

    Tsai, S.Y.; Smith, W.H.

    1983-12-01

    Radiological surveys were conducted to determine the potential migration of radionuclides from the waste area to the area commonly referred to as the Back Forty, located in the southern portion of the ARC site. The survey results indicated that parts of the Back Forty contain soils contaminated with uranium, thorium, and their associated decay products. A hydrogeologic characterization study was conducted at the Back Forty as part of an effort to more thoroughly assess radionuclide migration in the area. The objectives of the study were: (1) to define the soil characteristics and stratigraphy at the site, (2) to describe the general conditions of each geologic unit, and (3) to determine the direction and hydraulic gradient of areal groundwater flow. The site investigation activities included literature review of existing hydrogeological data for the Albany area, onsite borehold drilling, and measurement of groundwater levels. 7 references, 9 figures, 2 tables.

  7. Hydrogeologic assessment of shallow flow systems in the Walnut Formation, central Texas

    SciTech Connect

    Feckley, D.L. . Geology Dept.)

    1993-02-01

    The Walnut Formation crops out in the limestone dominated terrain of the Grand Prairie in Central Texas. The Walnut is the only clay-rich member within this dominantly limestone section. Because of its clay-rich nature, agricultural landuse of the Walnut Formation is greater than on surrounding formations. The clay content also makes the Walnut a natural consideration for waste disposal sites. However, many drainages and streams receive baseflow from the Walnut, and the Walnut overlies the Paluxy Aquifer, a minor aquifer in the State of Texas. Therefore, understanding the hydrogeology of the Walnut becomes increasingly important in order to protect baseflow water quality, and the underlying Paluxy Aquifer. Evaluation of hydrogeologic properties includes well hydrograph analysis, slug tests, pumping tests and laboratory tests. Results strongly indicate the presence of shallow flow systems, which are influenced by geomorphology and stratigraphy. An understanding of the geomorphic evolution of the region greatly aids the groundwater investigations.

  8. Allocating risk capital for a brownfields redevelopment project under hydrogeological and financial uncertainty.

    PubMed

    Yu, Soonyoung; Unger, Andre J A; Parker, Beth; Kim, Taehee

    2012-06-15

    In this study, we defined risk capital as the contingency fee or insurance premium that a brownfields redeveloper needs to set aside from the sale of each house in case they need to repurchase it at a later date because the indoor air has been detrimentally affected by subsurface contamination. The likelihood that indoor air concentrations will exceed a regulatory level subject to subsurface heterogeneity and source zone location uncertainty is simulated by a physics-based hydrogeological model using Monte Carlo realizations, yielding the probability of failure. The cost of failure is the future value of the house indexed to the stochastic US National Housing index. The risk capital is essentially the probability of failure times the cost of failure with a surcharge to compensate the developer against hydrogeological and financial uncertainty, with the surcharge acting as safety loading reflecting the developers' level of risk aversion. We review five methodologies taken from the actuarial and financial literature to price the risk capital for a highly stylized brownfield redevelopment project, with each method specifically adapted to accommodate our notion of the probability of failure. The objective of this paper is to develop an actuarially consistent approach for combining the hydrogeological and financial uncertainty into a contingency fee that the brownfields developer should reserve (i.e. the risk capital) in order to hedge their risk exposure during the project. Results indicate that the price of the risk capital is much more sensitive to hydrogeological rather than financial uncertainty. We use the Capital Asset Pricing Model to estimate the risk-adjusted discount rate to depreciate all costs to present value for the brownfield redevelopment project. A key outcome of this work is that the presentation of our risk capital valuation methodology is sufficiently generalized for application to a wide variety of engineering projects. PMID:22366499

  9. Geohydrodynamic properties of hydrogeological units in parts of Niger Delta, southern Nigeria

    NASA Astrophysics Data System (ADS)

    George, Nyakno J.; Emah, Joseph B.; Ekong, Ufot N.

    2015-05-01

    We used geophysical and laboratory techniques to study the geohydraulic properties of the geological units in the Niger Delta of southern Nigeria. Our main objective was to investigate the distribution of the geohydrodynamic parameters and to establish the interrelationships among them in the study area for effective characterisation of hydrogeological units. Measurements on the core samples aided in the estimation of effective porosities. The hydrogeological units' bulk resistivities measured from 1-D resistivity data constrained by nearby boreholes and the formation pore-water resistivities measured in the laboratory were used in computing the hydrogeological unit formation factor resistivity. Integration of field and laboratory measurements in conjunction with regression analysis of the data led to the determination of the hydrodynamic coefficients of the hydrogeological units. The graphs and the contour maps generated from the data show the variations and the interrelationships among the parameters. A theoretical model for the porosity-resistivity formation factor relation which conforms to Dakhnov's formulation, obtained for similar sediment with different grain sizes in another geological province has been developed based on the measured data. A good approximation with error of the mean square of 2.48 and standard deviation of 1.5 was obtained between the experimental aquifer formation factor F and the predicted aquifer formation factor Fm. Generally, the results of our study reveal good correlations with similar studies carried out in literatures at different places. The juxtaposition of contour maps which show variations of geohydraulic parameters in a continuum is worthwhile. The changes in geohydraulic parameters are influenced by size of grains, magnitude of pore sizes and shapes, pore-water and formation conductivities, facies changes and anisotropy of aquifer sediments. Our results have not really shown any interaction between freshwater and saltwater within the potential aquifers despite the proximity of the salt water within the area.

  10. Teaching and learning hydrogeology using a physically-based modelling framework

    NASA Astrophysics Data System (ADS)

    Frampton, Andrew; Dessirier, Benoit; Pannetier, Romain

    2014-05-01

    Hydrogeology involves studying the occurrence, distribution, movement and quality of water in geological formations. Hydrogeology typically enters in the curriculum of physical geography as well as civil and environmental engineering courses, is a multidisciplinary subject which encompasses several scientific areas including mathematics, physics, geology, geochemistry and numerical analysis. For applications such as resource management, decision and policy making, and an understanding and interpretation of uncertainty and risk assessment is also necessary. Teaching hydrogeology is not only challenged by its multidisciplinary nature, but also since groundwater occurrence and movement is hidden from view in the subsurface, and is generally inaccessible to direct observation. Field experiments are often costly and time consuming, and laboratory experiments limited in scale. However, suitably designed computational systems can help address such issues by providing numerical modelling investigations of field conditions. This contribution presents results from a recent project dedicated to develop an open-source, interactive, visual numerical modelling tool for teaching/learning hydrogeology, based on current pedagogical understanding of learning in higher education. It provides physically-based groundwater flow solutions within an intuitive user-friendly interface, which does not require advanced technical skills to operate. The aim is to be able to improve student's learning by providing immediate and visual feedback on groundwater flow and contaminant transport problems. The development and implementation of the tool as part of a teaching framework to address subsurface flow concepts and phenomena is presented, discussed and evaluated. By linking theoretical problem-solving exercises with modelling tasks in a learn-by-doing approach, we further discuss how student's learning experiences can be enhanced.

  11. Site hydrogeologic/geotechnical characterization report for Site B new municipal solid waste landfill

    SciTech Connect

    Reynolds, R.; Nowacki, P.

    1991-04-01

    This Site Hydrogeologic/Geotechnical Characterization Report (SHCR) presents the results of a comprehensive study conducted on a proposed solid waste landfill site, identified herein as Site B, at the Savannah River Site (SRS). This report is intended to satisfy all requirements of the South Carolina Department of Health and Environmental Control (SCDHEC) with regard to landfill siting requirements and ground water and environmental protection. In addition, this report provides substantial geotechnical data pertinent to the landfill design process.

  12. Evaluation of hydrogeologic aspects of proposed salinity control in Paradox Valley, Colorado

    USGS Publications Warehouse

    Konikow, Leonard F.; Bedinger, M.S.

    1978-01-01

    The salt load in the Dolores River increases by about 200,000 tons per year where it crosses Paradox Valley, Colorado, because of the discharge of a sodium chloride brine from an underlying aquifer. A ground-water management program to nearly eliminate this major source of salt, which eventually enters the Colorado River, can be designed on the basis of an accurate description of the hydrogeologic framework of Paradox Valley.

  13. Scale problems in assessment of hydrogeological parameters of groundwater flow models

    NASA Astrophysics Data System (ADS)

    Nawalany, Marek; Sinicyn, Grzegorz

    2015-09-01

    An overview is presented of scale problems in groundwater flow, with emphasis on upscaling of hydraulic conductivity, being a brief summary of the conventional upscaling approach with some attention paid to recently emerged approaches. The focus is on essential aspects which may be an advantage in comparison to the occasionally extremely extensive summaries presented in the literature. In the present paper the concept of scale is introduced as an indispensable part of system analysis applied to hydrogeology. The concept is illustrated with a simple hydrogeological system for which definitions of four major ingredients of scale are presented: (i) spatial extent and geometry of hydrogeological system, (ii) spatial continuity and granularity of both natural and man-made objects within the system, (iii) duration of the system and (iv) continuity/granularity of natural and man-related variables of groundwater flow system. Scales used in hydrogeology are categorised into five classes: micro-scale - scale of pores, meso-scale - scale of laboratory sample, macro-scale - scale of typical blocks in numerical models of groundwater flow, local-scale - scale of an aquifer/aquitard and regional-scale - scale of series of aquifers and aquitards. Variables, parameters and groundwater flow equations for the three lowest scales, i.e., pore-scale, sample-scale and (numerical) block-scale, are discussed in detail, with the aim to justify physically deterministic procedures of upscaling from finer to coarser scales (stochastic issues of upscaling are not discussed here). Since the procedure of transition from sample-scale to block-scale is physically well based, it is a good candidate for upscaling block-scale models to local-scale models and likewise for upscaling local-scale models to regional-scale models. Also the latest results in downscaling from block-scale to sample scale are briefly referred to.

  14. Borehole Completion and Conceptual Hydrogeologic Model for the IFRC Well Field, 300 Area, Hanford Site

    SciTech Connect

    Bjornstad, Bruce N.; Horner, Jacob A.; Vermeul, Vincent R.; Lanigan, David C.; Thorne, Paul D.

    2009-04-20

    A tight cluster of 35 new wells was installed over a former waste site, the South Process Pond (316-1 waste site), in the Hanford Site 300 Area in summer 2008. This report documents the details of the drilling, sampling, and well construction for the new array and presents a summary of the site hydrogeology based on the results of drilling and preliminary geophysical logging.

  15. Aquifer sensitivity to pesticide leaching: Testing a soils and hydrogeologic index method

    USGS Publications Warehouse

    Mehnert, E.; Keefer, D.A.; Dey, W.S.; Wehrmann, H.A.; Wilson, S.D.; Ray, C.

    2005-01-01

    For years, researchers have sought index and other methods to predict aquifer sensitivity and vulnerability to nonpoint pesticide contamination. In 1995, an index method and map were developed to define aquifer sensitivity to pesticide leaching based on a combination of soil and hydrogeologic factors. The soil factor incorporated three soil properties: hydraulic conductivity, amount of organic matter within individual soil layers, and drainage class. These properties were obtained from a digital soil association map. The hydrogeologic factor was depth to uppermost aquifer material. To test this index method, a shallow ground water monitoring well network was designed, installed, and sampled in Illinois. The monitoring wells had a median depth of 7.6 m and were located adjacent to corn and soybean fields where the only known sources of pesticides were those used in normal agricultural production. From September 1998 through February 2001, 159 monitoring wells were sampled for 14 pesticides but no pesticide metabolites. Samples were collected and analyzed to assess the distribution of pesticide occurrence across three units of aquifer sensitivity. Pesticides were detected in 18% of all samples and nearly uniformly from samples from the three units of aquifer sensitivity. The new index method did not predict pesticide occurrence because occurrence was not dependent on the combined soil and hydrogeologic factors. However, pesticide occurrence was dependent on the tested hydrogeologic factor and was three times higher in areas where the depth to the uppermost aquifer was <6 m than in areas where the depth to the uppermost aquifer was 6 to <15 m. Copyright ?? 2005 National Ground Water Association.

  16. Geologic framework and hydrogeologic characteristics of the Edwards Aquifer outcrop, Comal County, Texas

    USGS Publications Warehouse

    Small, T.A.; Hanson, J.A.

    1994-01-01

    All of the hydrogeologic subdivisions within the Edwards aquifer outcrop in Comal County have some porosity and permeability. The most porous and permeable appear to be hydrogeologic subdivision VI, the Kirschberg evaporite member of the Kainer Formation; hydrogeologic subdivision III, the leached and collapsed members, undivided; and hydro- geologic subdivision II, the cyclic and marine members, undivided, of the Person Formation. The two types of porosity in the Edwards aquifer outcrop are fabric selective, which is related to depositional or diagenetic elements and typically exists in specific stratigraphic horizons; and not fabric selective, which can exist in any litho- stratigraphic horizon. Two faults, Comal Springs and Hueco Springs, completely, or almost completely, offset the Edwards aquifer along much of their respective traces across Comal County. Porous and permeable Edwards aquifer limestones are juxtaposed against impermeable upper confining beds along all, or most of their traces across Comal County. These faults could be barriers, or partial barriers, to ground-water flow where the aquifer is offset. In Comal County, the Edwards aquifer is probably most vulnerable to surface contamination in the rapidly urbanizing areas on the Edwards aquifer outcrop. Possible contamination can result from spills, leakage of hazardous materials, or runoff onto the intensely faulted and fractured, karstic limestone outcrops characteristics of the recharge zone.

  17. Improvements in near-surface geophysical applications for hydrogeological parameter estimation

    NASA Astrophysics Data System (ADS)

    Addison, Adrian Demond

    One application of near-surface geophysical techniques is the hydrogeological parameter estimation. Hydrogeological estimated parameters such as volumetric water content, porosity, and hydraulic conductivity are useful in predicting groundwater flow. Therefore, any improvements in the field acquisition and data processing of the geophysical data will provide better results in estimating these parameters. This research examines the difficulties associated with processing and attribute analyses with shallow seismic P-wave reflection data, the application of the empirical mode decomposition (EMD) as a processing tool for ground-penetrating radar (GPR), and the use of GPR as tool in the assessment of bank filtration. Near-surface seismic reflection data are difficult to process because of the lack of reflections in the shot gathers; however, this research demonstrated that the application of certain steps such F-k filtering and velocity analysis can achieve the desired result, a more robust geologic model. The EMD technique was applied (removal of the WOW noise) to processing steps for GPR data in estimating hydrogeological parameters by providing significant stability during the calculation of dielectric constants. GPR techniques are widely known and diverse, but one rather different application of the GPR was to assess the suitability of bank filtration at a site in South Carolina. Finally, a multi-attribute analysis approach, a rather new application for near-surface seismic data, was used in predicting porosity from well logs and seismic data.

  18. Reconnaissance hydrogeologic investigation of the Defense Waste Processing Facility and Vicinity, Savannah River Plant, South Carolina

    SciTech Connect

    Dennehy, K.F.; Prowell, D.C.; McMahon, P.B.

    1989-01-01

    The purposes of this report are two-fold: (1) to define the hydrogeologic conditions in the vicinity of the defense waste processing facility (DWPF) and, (2) to evaluate the potential for movement of a concentrated salt-solution waste if released at or near the DWPF. These purposes were accomplished by assembling and evaluating existing hydrogeologic data; collecting additional geologic, hydrologic, and water-quality data; developing a local geologic framework; developing a conceptual model of the local ground-water flow system; and by performing laboratory experiments to determine the mobility of salt-solution waste in surface and near-surface sediments. Although the unconsolidated sediments are about 1000 ft thick in the study area, only the Tertiary age sediments, or upper 300 ft are discussed in this report. The top of the Ellenton Formation acts as the major confining unit between the overlying aquifers in Tertiary sediments and the underlying aquifers in Cretaceous sediments; therefore, the Ellenton Formation is the vertical limit of our hydrogeologic investigation. The majority of the hydrologic data for this study come from monitoring wells at the saltstone disposal site (SDS) in Z Area (fig. 3). No recent water-level data were collected in S Area owing to the removal of S Area monitoring wells prior to construction at the DWPF. 46 refs., 26 figs., 7 tabs.

  19. Environmental assessment of a uranium experimental rock blasting in Portugal, using geophysical and hydrogeological methods

    NASA Astrophysics Data System (ADS)

    Ramalho, E. C.; Midões, C.; Lourenço, M. C.; Costa, A.; Monteiro Santos, F. A.

    2012-10-01

    The Nisa uranium deposit, located in Central Portugal, has been known since the late 1960s. Some areas were explored at that time. Today, a few open pits and dumps remain in place and are a concern to local authorities. To assess the geoenvironmental problems caused by the main mining exploration composed of an experimental rock blasting, 3D electrical conductivity and resistivity models were made to develop a hydrogeological model to understand the possibility of contaminants transportation, such as uranium, from the dumps towards a dam located nearby. These 3D models were the support to show alteration layer thickness variations and fault zones at depths controlling groundwater circulation. Spectrometric surveys were also carried out and correlated with geology and geoelectrical structure. All this information was used in the construction of the 3D steady state hydrogeological model of the experimental rock blasting of Nisa. In this model, groundwater flow and the contaminant pathways were simulated. Some areas have very high radioactive values resulting from the geological formation characteristics and old dumps. However, results of the environmental assessment using geophysical and hydrogeological methods point to a critical situation restricted only to the area of the experimental rock blasting of the Nisa uranium deposit and its dumps.

  20. Hydrogeologic investigation of the Advanced Coal Liquefaction Research and Development Facility, Wilsonville, Alabama

    SciTech Connect

    Gardner, F.G.; Kearl, P.M.; Mumby, M.E.; Rogers, S.

    1996-09-01

    This document describes the geology and hydrogeology at the former Advanced Coal Liquefaction Research and Development (ACLR&D) facility in Wilsonville, Alabama. The work was conducted by personnel from the Oak Ridge National Laboratory Grand Junction office (ORNL/GJ) for the U.S. Department of Energy (DOE) Pittsburgh Energy Technology Center (PETC). Characterization information was requested by PETC to provide baseline environmental information for use in evaluating needs and in subsequent decision-making for further actions associated with the closeout of facility operations. The hydrogeologic conceptual model presented in this report provides significant insight regarding the potential for contaminant migration from the ACLR&D facility and may be useful during other characterization work in the region. The ACLR&D facility is no longer operational and has been dismantled. The site was characterized in three phases: the first two phases were an environmental assessment study and a sod sampling study (APCO 1991) and the third phase the hydraulic assessment. Currently, a Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) remedial investigation (RI) to address the presence of contaminants on the site is underway and will be documented in an RI report. This technical memorandum addresses the hydrogeologic model only.

  1. Hydrogeology along the southern boundary of the Hanford Site between the Yakima and Columbia Rivers, Washington

    SciTech Connect

    Liikala, T.L.

    1994-09-01

    US Department of Energy (DOE) operations at the Hanford Site, located in southeastern Washington, have generated large volumes of hazardous and radioactive wastes since 1944. Some of the hazardous wastes were discharged to the ground in the 1100 and 3000 Areas, near the city of Richland. The specific waste types and quantities are unknown; however, they probably include battery acid, antifreeze, hydraulic fluids, waste oils, solvents, degreasers, paints, and paint thinners. Between the Yakima and Columbia rivers in support of future hazardous waste site investigations and ground-water and land-use management. The specific objectives were to collect and review existing hydrogeologic data for the study area and establish a water-level monitoring network; describe the regional and study area hydrogeology; develop a hydrogeologic conceptual model of the unconfined ground-water flow system beneath the study area, based on available data; describe the flow characteristics of the unconfined aquifer based on the spatial and temporal distribution of hydraulic head within the aquifer; use the results of this study to delineate additional data needs in support of future Remedial Investigation/Feasibility Studies (RI/FS), Fate and Transport modeling, Baseline Risk Assessments (BRA), and ground-water and land-use management.

  2. The application of geographic information systems technology to geologic, hydrogeologic, and environmental research

    SciTech Connect

    Tew, B.H.; Irvin, G.D.

    1994-12-31

    Spatial data are of primary importance in nearly all aspects of geological and hydrogeological research. In undertaking such research, it is fundamental that observations and phenomena be located in a georeferenced coordinant system in order to understand and visualize the distribution of these data and to discern their relationships to other observations and phenomena. For this reason, geologic studies are particularly well suited to take advantage of computer-based geographic information system (GIS) technology, which combines the data input, storage, retrieval, analysis, and manipulation functions of a relational database with automated mapping and data visualization capability. GIS allows data to be analyzed and visualized in ways that would be too time consuming, too cost prohibitive, or nearly impossible to perform using other methods. Geological applications for GIS and related technology range from basic management of locational data (e.g., water or hydrocarbon well locations, sample localities, land holdings, etc.) and associated attribute information to detailed geologic mapping and complex analyses and modeling of hydrocarbon reservoirs, aquifer systems, or drainage basins. We have implemented GIS with the primary near-term function of supporting and enhancing our geological and hydrogeological research programs. Current research applications include monitoring and modeling of nonpoint source pollutant loadings to aquifer systems and drainage basins, delineation of public water supply wellhead protection areas, hydrogeologic flow modeling, and environmental monitoring. Examples from these studies serve to illustrate the applicability and efficiency of the GIS approach to geologic research.

  3. Hydrogeologic Framework Model for the Saturated Zone Site Scale flow and Transport Model

    SciTech Connect

    T. Miller

    2004-11-15

    The purpose of this report is to document the 19-unit, hydrogeologic framework model (19-layer version, output of this report) (HFM-19) with regard to input data, modeling methods, assumptions, uncertainties, limitations, and validation of the model results in accordance with AP-SIII.10Q, Models. The HFM-19 is developed as a conceptual model of the geometric extent of the hydrogeologic units at Yucca Mountain and is intended specifically for use in the development of the ''Saturated Zone Site-Scale Flow Model'' (BSC 2004 [DIRS 170037]). Primary inputs to this model report include the GFM 3.1 (DTN: MO9901MWDGFM31.000 [DIRS 103769]), borehole lithologic logs, geologic maps, geologic cross sections, water level data, topographic information, and geophysical data as discussed in Section 4.1. Figure 1-1 shows the information flow among all of the saturated zone (SZ) reports and the relationship of this conceptual model in that flow. The HFM-19 is a three-dimensional (3-D) representation of the hydrogeologic units surrounding the location of the Yucca Mountain geologic repository for spent nuclear fuel and high-level radioactive waste. The HFM-19 represents the hydrogeologic setting for the Yucca Mountain area that covers about 1,350 km2 and includes a saturated thickness of about 2.75 km. The boundaries of the conceptual model were primarily chosen to be coincident with grid cells in the Death Valley regional groundwater flow model (DTN: GS960808312144.003 [DIRS 105121]) such that the base of the site-scale SZ flow model is consistent with the base of the regional model (2,750 meters below a smoothed version of the potentiometric surface), encompasses the exploratory boreholes, and provides a framework over the area of interest for groundwater flow and radionuclide transport modeling. In depth, the model domain extends from land surface to the base of the regional groundwater flow model (D'Agnese et al. 1997 [DIRS 100131], p 2). For the site-scale SZ flow model, the HFM-19 is clipped, reducing the vertical extent to the interpreted top of the water table. The HFM-19 grid consists of a rectangular array of nodes with a spacing of 125 meters discussed in Sections 4.1, 5, and 6.3, and this selection simplifies the available data near the repository and extrapolates from very widely spaced data in other areas of the model domain. The HFM-19 is assembled by using geometric gridding techniques and software (described in Sections 3 and 6.3) to fill the domain area with 3-D elements corresponding to the 19 hydrogeologic units of interest. The HFM-19 is limited by simplifications that accommodate computer mapping, framework modeling, and modeling limitations and contains an inherent level of uncertainty that is a function of data distribution and geologic complexity. Uncertainty and limitations are discussed in Section 6.4 and model validation is discussed in Section 7. The HFM-19 provides the hydrogeologically defined internal geometry for SZ flow and transport process models, which was used to assign unit numbers to nodes in a mesh for use in site-scale SZ flow and transport models. The ''Saturated Zone Site-Scale Flow Model'' (BSC 2004 [DIRS 170037]) directly uses the output of this report to provide the spatial boundaries for each of the hydrogeologic units.

  4. Hydrogeophysics and remote sensing for the design of hydrogeological conceptual models in hard rocks - Sardón catchment (Spain)

    NASA Astrophysics Data System (ADS)

    Francés, Alain P.; Lubczynski, Maciek W.; Roy, Jean; Santos, Fernando A. M.; Mahmoudzadeh Ardekani, Mohammad R.

    2014-11-01

    Hard rock aquifers are highly heterogeneous and hydrogeologically complex. To contribute to the design of hydrogeological conceptual models of hard rock aquifers, we propose a multi-techniques methodology based on a downward approach that combines remote sensing (RS), non-invasive hydrogeophysics and hydrogeological field data acquisition. The proposed methodology is particularly suitable for data scarce areas. It was applied in the pilot research area of Sardón catchment (80 km2) located west of Salamanca (Spain). The area was selected because of hard-rock hydrogeology, semi-arid climate and scarcity of groundwater resources. The proposed methodology consisted of three main steps. First, we detected the main hydrogeological features at the catchment scale by processing: (i) a high resolution digital terrain model to map lineaments and to outline fault zones; and (ii) high-resolution, multispectral satellite QuickBird and WorldView-2 images to map the outcropping granite. Second, we characterized at the local scale the hydrogeological features identified at step one with: i) ground penetrating radar (GPR) to assess groundwater table depth complementing the available monitoring network data; ii) 2D electric resistivity tomography (ERT) and frequency domain electromagnetic (FDEM) to retrieve the hydrostratigraphy along selected survey transects; iii) magnetic resonance soundings (MRS) to retrieve the hydrostratigraphy and aquifer parameters at the selected survey sites. In the third step, we drilled 5 boreholes (25 to 48 m deep) and performed slug tests to verify the hydrogeophysical interpretation and to calibrate the MRS parameters. Finally, we compiled and integrated all acquired data to define the geometry and parameters of the Sardón aquifer at the catchment scale. In line with a general conceptual model of hard rock aquifers, we identified two main hydrostratigraphic layers: a saprolite layer and a fissured layer. Both layers were intersected and drained by fault zones that control the hydrogeology of the catchment. The spatial discontinuities of the saprolite layer were well defined by RS techniques while subsurface geometry and aquifer parameters by hydrogeophysics. The GPR method was able to detect shallow water table at depth between 1 and 3 m b.g.s. The hydrostratigraphy and parameterization of the fissured layer remained uncertain because ERT and FDEM geophysical methods were quantitatively not conclusive while MRS detectability was restricted by low volumetric water content. The proposed multi-technique methodology integrating cost efficient RS, hydrogeophysics and hydrogeological field investigations allowed us to characterize geometrically and parametrically the Sardón hard rock aquifer system, facilitating the design of hydrogeological conceptual model of the area.

  5. Hydrogeologic and water-quality data for the explosive experimental area, Naval Surface Warfare Center, Dahlgren Site, Dahlgren, Virginia

    USGS Publications Warehouse

    Hammond, E.C.; Bell, C.F.

    1995-01-01

    Hydrogeologic and water-quality data were collected at the Explosive Experimental Area, Naval Surface Warfare Center, Dahlgren Site at Dahlgren, Virginia, as part of a hydrogeologic assessment of the shallow aquifer system begun in 1993. The U.S. Geological Survey conducted this study to provide the U.S. Navy with hydrogeologic data to aid in the evaluation of the effects from remediation of contaminated sites and to protect against additional contamination. This report describes the ground-water observation- well network, hydrogeologic, and water-quality data collected between October 1993 and April 1995. The report includes a description of the locations and construction of 28 observation wells on the Explosive Experimental Area. Hydrogeologic data include lithologic logs, geophysical logs, and vertical hydraulic conductivity measurements of selected core intervals. Hydrologic data include synoptic and hourly measurements of ground-water levels, and observation-well slug tests to determine horizontal hydraulic conductivity. Water-quality data include analyses of major dissolved constituents in ground water and surface water.

  6. On the significance of contaminant plume-scale and dose-response models in defining hydrogeological characterization needs

    NASA Astrophysics Data System (ADS)

    de Barros, F.; Rubin, Y.; Maxwell, R.; Bai, H.

    2007-12-01

    Defining rational and effective hydrogeological data acquisition strategies is of crucial importance since financial resources available for such efforts are always limited. Usually such strategies are developed with the goal of reducing uncertainty, but less often they are developed in the context of the impacts of uncertainty. This paper presents an approach for determining site characterization needs based on human health risk factors. The main challenge is in striking a balance between improved definition of hydrogeological, behavioral and physiological parameters. Striking this balance can provide clear guidance on setting priorities for data acquisition and for better estimating adverse health effects in humans. This paper addresses this challenge through theoretical developments and numerical testing. We will report on a wide range of factors that affect the site characterization needs including contaminant plume's dimensions, travel distances and other length scales that characterize the transport problem, as well as health risk models. We introduce a new graphical tool that allows one to investigate the relative impact of hydrogeological and physiological parameters in risk. Results show that the impact of uncertainty reduction in the risk-related parameters decreases with increasing distances from the contaminant source. Also, results indicate that human health risk becomes less sensitive to hydrogeological measurements when dealing with ergodic plumes. This indicates that under ergodic conditions, uncertainty reduction in human health risk may benefit from better understanding of the physiological component as opposed to a detailed hydrogeological characterization

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

    USGS Publications Warehouse

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

    2013-01-01

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

  8. The KINDRA H2020 Project: a knowledge inventory for hydrogeology research

    NASA Astrophysics Data System (ADS)

    Petitta, Marco; Bodo, Balazs; Caschetto, Mariachiara; Correia, Victor; Cseko, Adrienn; Fernandez, Isabel; Hartai, Eva; Hinsby, Klaus; Madarasz, Tamas; Garcia Padilla, Mercedes; Szucs, Peter

    2015-04-01

    Hydrogeology-related research activities cover a wide spectrum of research areas at EU and national levels. This fact is due to the intrinsic nature of the "water" topic, representing a key-aspect of the modern society: water is not only necessary for human, biological and environmental requirements, but it is one basic "engine" of several interconnected research topics, including energy, health, climate, food, security and others as exemplified by the water-food-energy-climate nexus described by e.g. the World Economic Forum. With respect to the water cycle, the management of groundwater brings additional challenges to the implementation of the Water Framework Directive (WFD) and climate change adaptation (such as integrated transboundary management of groundwater resources). This fact is related to the nature of groundwater, which represents the "hidden" part of the water cycle, difficult to evaluate, communicate and appreciate, although it sustains the health of both humans and ecosystems as well as industrial and agricultural production. In general, groundwater has been considered mainly for its relationships with surface waters, influencing river flow, e-flows, GDE (groundwater-dependent ecosystems), pollutant fate, agricultural practices, water scarcity and others. In this framework, the importance of groundwater inside the WFD has been reinforced by the daughter directive on groundwater. In the last years, particular insights have been developed on surface waters/groundwater interactions and several related research projects have been carried out. Nevertheless, a specific focus on hydrogeology, the science branch studying groundwater, has not looked into until now, despite of its utmost importance as renewable, high-quality, naturally protected (but still vulnerable) resource. At the same time the European knowledge-base that has been acquired on this important topic is widespread into several projects, plans, actions, realized at national and fragmented into wider programs generally related to water, environment or ecology. In order to have a comprehensive understanding on the groundwater theme, it is necessary to create a "snapshot" of our scientific knowledge as of 2015/2016 covering as many European countries as possible. Such comprehensive coverage will result in an accurate assessment of the state of the art in hydrogeology research in various geographical and geo-environmental settings, allowing for direct comparison and the exploitation of synergies. The KINDRA project (Knowledge Inventory for hydrogeology research, Grant Agreement No. 642047, www.kindraproject.eu) seeks to create a critical mass for scientific knowledge exchange of hydrogeology research, to ensure wide applicability of research results, including support of innovation and development, and to reduce unnecessary duplication of efforts. KINDRA is funded by the European Commission's HORIZON2020 Framework Programme. The project started on 1 January 2015 with the overall objective to take stock of our contemporary knowledge of hydrogeology with the help of an inventory of research results, activities, projects and programmes, and then use the inventory to identify critical research challenges and gaps, with a view to avoiding overlaps. This approach takes into account the implementation of the WFD and new innovation areas within integrated water resources management, allowing at EU scale the future correct management and policy development of groundwater.

  9. Hydrogeologic facies characterization of an alluvial fan near Fresno, California, using geophysical techniques

    USGS Publications Warehouse

    Burow, Karen R.; Weissmann, G.S.; Miller, R.D.; Placzek, Gary

    1997-01-01

    DBCP (1,2-dibromo-3-chloropropane) contamination in the sole source aquifer near Fresno, California, has significantly affected drinking-water supplies. Borehole and surface geophysical data were integrated with borehole textural data to characterize the Kings River alluvial fan sediments and to provide a framework for computer modeling of pesticide transport in ground water. Primary hydrogeologic facies units, such as gravel, coarse sand or gravel, fine sand, and silt and clay, were identified in cores collected from three borings located on a 4.6-kilometer transect of multilevel monitoring wells. Borehole geophysical logs collected from seven wells and surface geophysical surveys were used to extrapolate hydrogeologic facies to depths of about 82meters and to correlate the facies units with neighboring drilling sites. Thickness ranged from 0.3to 13 meters for sand and gravel units, and from 0.3 to 17 meters for silt and clay. The lateral extent of distinct silt and clay layers was mapped using shallow seismic reflection and ground-penetrating radar techniques. About 3.6 kilometers of seismic reflection data were collected; at least three distinct fine-grained layers were mapped. The depth of investigation of the seismic survey ranged from 34 to 107 meters below land surface, and vertical resolution was about 3.5 meters. The ground-penetrating radar survey covered 3.6kilometers and imaged a 1.5-meters thick, continuous fine-grained layer located at a depth of about 8 meters. Integrated results from the borehole sediment descriptions and geophysical surveys provided a detailed characterization over a larger areal extent than traditional hydrogeologic methods alone.

  10. Hydrogeologic setting and conceptual hydrologic model of the Spring Creek basin, Centre County, Pennsylvania

    USGS Publications Warehouse

    Fulton, John W.; Koerkle, Edward H.; McAuley, Steven D.; Hoffman, Scott A.; Zarr, Linda F.

    2005-01-01

    The Spring Creek Basin, Centre County, Pa., is experiencing some of the most rapid growth and development within the Commonwealth. This trend has resulted in land-use changes and increased water use, which will affect the quantity and quality of stormwater runoff, surface water, ground water, and aquatic resources within the basin. The U.S. Geological Survey (USGS), in cooperation with the ClearWater Conservancy (CWC), Spring Creek Watershed Community (SCWC), and Spring Creek Watershed Commission (SCWCm), has developed a Watershed Plan (Plan) to assist decision makers in water-resources planning. One element of the Plan is to provide a summary of the basin characteristics and a conceptual model that incorporates the hydrogeologic characteristics of the basin. The report presents hydrogeologic data for the basin and presents a conceptual model that can be used as the basis for simulating surface-water and ground-water flow within the basin. Basin characteristics; sources of data referenced in this text; physical characteristics such as climate, physiography, topography, and land use; hydrogeologic characteristics; and water-quality characteristics are discussed. A conceptual model is a simplified description of the physical components and interaction of the surface- and ground-water systems. The purpose for constructing a conceptual model is to simplify the problem and to organize the available data so that the system can be analyzed accurately. Simplification is necessary, because a complete accounting of a system, such as Spring Creek, is not possible. The data and the conceptual model could be used in development of a fully coupled numerical model that dynamically links surface water, ground water, and land-use changes. The model could be used by decision makers to manage water resources within the basin and as a prototype that is transferable to other watersheds.

  11. A REVIEW OF NON-INVASIVE IMAGING METHODS AND APPLICATIONS IN CONTAMINANT HYDROGEOLOGY RESEARCH

    SciTech Connect

    Werth, Charles J.; Zhang, Changyong; Brusseau, M. L.; Oostrom, Martinus; Baumann, T.

    2010-03-08

    Contaminant hydrogeological processes occurring in porous media are typically not amenable to direct observation. As a result, indirect measurements (e.g., contaminant breakthrough at a fixed location) are often used to infer processes occurring at different scales, locations, or times. To overcome this limitation, non-invasive imaging methods are increasingly being used in contaminant hydrogeology research. The most common methods, and the subjects of this review, are optical imaging using UV or visible light, dual-energy gamma-radiation, X-ray microtomography, and magnetic resonance imaging (MRI). Non-invasive imaging techniques have provided valuable insights into a variety of complex systems and processes, including porous media characterization, multiphase fluid distribution, fluid flow, solute transport and mixing, colloidal transport and deposition, and reactions. In this paper we review the theory underlying these methods, applications of these methods to contaminant hydrogeology research, and methods’ advantages and disadvantages. As expected, there is no perfect method or tool for non-invasive imaging. However, optical methods generally present the least expensive and easiest options for imaging fluid distribution, solute and fluid flow, colloid transport, and reactions in artificial two-dimensional (2D) porous media. Gamma radiation methods present the best opportunity for characterization of fluid distributions in 2D at the Darcy scale. X-ray methods present the highest resolution and flexibility for three-dimensional (3D) natural porous media characterization, and 3D characterization of fluid distributions in natural porous media. And MRI presents the best option for 3D characterization of fluid distribution, fluid flow, colloid transport, and reaction in artificial porous media. Obvious deficiencies ripe for method development are the ability to image transient processes such as fluid flow and colloid transport in natural porous media in three-dimensions, the ability to image many reactions of environmental interest in artificial and natural porous media, and the ability to image selected processes over a range of scales in artificial and natural porous media.

  12. Flow and transport in unsaturated fractured rock: Effects of multiscale heterogeneity of hydrogeologic properties

    SciTech Connect

    Zhou, Quanlin; Liu, Hui-Hai; Bodvarsson, Gudmundur S.; Oldenburg, Curtis M.

    2002-07-09

    The heterogeneity of hydrogeologic properties at different scales may have different effects on flow and transport processes in a subsurface system. A model for the unsaturated zone of Yucca Mountain, Nevada, is developed to represent complex heterogeneity at two different scales: (1) layer scale corresponding to geologic layering and (2) local scale. The layer-scale hydrogeologic properties are obtained using inverse modeling, based on the available measurements collected from the Yucca Mountain site. Calibration results show a significant lateral and vertical variability in matrix and fracture properties. Hydrogeologic property distributions in a two-dimensional, vertical cross section of the site are generated by combining the average layer-scale matrix and fracture properties with local-scale perturbations generated using a stochastic simulation method. The unsaturated water flow and conservative (nonsorbing) tracer transport through the cross section are simulated for different sets of matrix and fracture property fields. Comparison of simulation results indicates that the local-scale heterogeneity of matrix and fracture properties has a considerable effect on unsaturated flow processes, leading to fast flow paths in fractures and the matrix. These paths shorten the travel time of a conservative tracer from the source (repository) horizon in the unsaturated zone to the water table for small fractions of total released tracer mass. As a result, the local-scale heterogeneity also has a noticeable effect on global tracer transport processes, characterized by an average breakthrough curve at the water table, especially at the early arrival time of tracer mass. However, the effect is not significant at the later time after 20 percent tracer mass reaches the water table. The simulation results also verify that matrix diffusion plays an important role in overall solute transport processes in the unsaturated zone at Yucca Mountain.

  13. Hydrogeology of an ancient arid closed basin: Implications for tabular sandstone-hosted uranium deposits

    SciTech Connect

    Sanford, R.F. )

    1990-11-01

    Hydrogeologic modeling shows that tabular-type uranium deposits in the grants uranium region of the San Juan basin, New Mexico, formed in zones of ascending and discharging regional ground-water flow. The association of either lacustrine mudstone or actively subsiding structures and uranium deposits can best be explained by the occurrence of lakes at topographic depressions where ground water having different sources and compositions is likely to converge, mix, and discharge. Ascending and discharging flow also explains the association of uranium deposits with underlying evaporites and suggests a brine interface. The simulations contradict previous suggestions that ground water moved downward in the mudflat.

  14. Hydrogeology of closed basins and deserts of South America, ERTS-1 interpretations

    NASA Technical Reports Server (NTRS)

    Stoertz, G. E.; Carter, W. D.

    1973-01-01

    Images from the Earth Resources Technology Satellite (ERTS-1) contain data useful in studies of hydrogeology, geomorphology, and paleoclimatology. Sixteen Return Beam Vidicon (RBV) images and 15 Multi-Spectral Scanner (MSS) images were studied. These covered deserts and semidesert areas in southwestern Bolivia, northwestern Argentina, northern Chile, and southeastern Peru from July 30 to November 17, 1972. During the first 3 months after launching, high-quality cloud-free imagery was obtained over approximately 90 percent of the region of interior drainage, or an area of 170,000 square miles.

  15. Geologic framework and hydrogeologic characteristics of the outcrops of the Edwards and Trinity aquifers, Medina Lake area, Texas

    USGS Publications Warehouse

    Small, Ted A.; Lambert, Rebecca B.

    1998-01-01

    The hydrogeologic subdivisions of the Edwards aquifer outcrop in the Medina Lake area in Medina and Bandera Counties generally are porous and permeable. The most porous and permeable appear to be hydrogeologic subdivision VI, the Kirschberg evaporite member of the Kainer Formation; and hydrogeologic subdivision III, the leached and collapsed members, undivided, of the Person Formation. The porosity of the rocks in the Edwards aquifer outcrop is related to depositional or diagenetic elements along specific stratigraphic horizons (fabric selective) and to dissolution and structural elements that can occur in any lithostratigraphic horizon (not fabric selective). Permeability depends on the physical properties of the rock such as size, shape, and distribution of pores. The Edwards aquifer has relatively large porosity and permeability resulting, in part, from the development or redistribution of secondary porosity. Lithology, stratigraphy, diagenesis, and karstification account for the effective porosity and permeability in the Edwards aquifer outcrop. Karst features that can greatly enhance effective porosity and permeability in the Edwards aquifer outcrop include sinkholes, dolines, and caves. Field observations in the Medina Lake area confirm the findings of previous investigators that Medina Lake mostly overlies rocks of the upper member of the Glen Rose Limestone. The channel downstream of Medina Dam to the upper end of Diversion Lake also overlies the upper member of the Glen Rose Limestone. Most of Diversion Lake overlies a thin section of the Edwards aquifer?hydrogeologic subdivision VIII (basal nodular member) and the basal part of hydrogeologic subdivision VII (dolomitic member). Hydrogeologic subdivisions VIII and VII might be hydraulically connected to Medina Lake at high lake stages. The Trinity aquifer, which crops out in the northern part of the Medina Lake area and underlies the Edwards aquifer in the southern part, is much less permeable and productive than the Edwards aquifer. Where the Trinity aquifer underlies the Edwards, the Trinity acts as a lower confining unit on the Edwards.

  16. Application of cone penetrometer technology in hydrogeological investigations at the Savannah River Site (SRS), South Carolina

    SciTech Connect

    Pelt, R.S. van; Rossabi, J.; Kaback, D.S.; Jordan, J.E.; Looney, B.B.; Bergren, C.L. )

    1992-01-01

    The Savannah River Site is currently utilizing Cone Penetrometer Testing (CPT) as a screening tool in hydrogeological investigations of waste units. CPT technology is being employed to assess the subsurface near the M-Area Settling Basin, a former waste effluent disposal basin. The cone penetrometer is being used to better characterize the geology (continuity, thickness), hydrology (potentiometric and pore pressure data), and to obtain further information about the extent of organic contaminants at this location. The cone penetrometer is also utilized for the collection of groundwater and soil samples. CPT technology includes a hydraulic system to push a sensing tool downward into the subsurface. Parameters measured by integrated Cone Penetrometer sensors include tip pressure, sleeve resistance, pore pressure, electrical resistivity, and chemical concentration by fiber optics, hydrogeological, and spatiotemporal concentration data. Liquid, vapor, and solid samples can also be taken from predetermined depths for analysis. Advantages of using CPT are: drill cuttings and fluids are not generated; borehole invasion is minimized (reducing the likelihood of spreading organic contaminants); capability exists to grout the borehole in conjunction with retrieval of the sensing tool; and, efficient data acquisition and interpretation allows for strategic and more cost-effective monitor well placement.

  17. The hydrogeology of the Lake Waco Formation: Eagle Ford Group, central Texas

    SciTech Connect

    Bradley, R.G.; Yelderman, J.C. Jr. . Geology Dept.)

    1993-02-01

    The Lake Waco Formation in central Texas crops out west of a major urban growth corridor along Interstate Highway 35. The development associated with this corridor increases the need for landfills and the possibility of leaks and spills. The Lake Waco Formation is predominantly shale and presently used for a regional landfill in the study area. It is not considered an aquifer and subsequently limited hydrogeological information exists. However, a numerous shallow wells occur in the weathered bedrock veneer and the shallow groundwater is directly connected to surface streams. Investigations revealed flow along bedding plane separations and fractures. The effective porosity is estimated to be less than .5 percent. Lab permeameter tests, slug tests, and constant-rate pumping tests were used to evaluate hydrogeologic parameters. Storage coefficient values range from .0017 to .0063 with a mean value of .0032. Hydraulic conductivity values decreased with depth and averaged 1.7 [times] 10 [sup [minus]4] cm/s for weathered shale and 1.4 [times] 10[sup [minus]7] cm/s for unweathered shale. Groundwater flow studies using piezometers exhibit topographic control of flow with horizontal to vertical anisotropy due to increased fracturing near the surface, but no noticeable horizontal anisotropic influence from fractures. Multiple-well pumping tests reveal horizontal anisotropic flow under pumping stress that is not present under static conditions and is complicated by heterogeneity.

  18. Hydrogeological characterization and first CO2 injection experiment in the Heletz sands Reservoir, Heletz (Israel)

    NASA Astrophysics Data System (ADS)

    Bensabat, Jacob; Niemi, Auli; Tsang, Chin-Fu; Sharma, Prabhakar; Carrera, Jesus; Sauter, Martin; Tatomir, Alexandru; Ghergut, Iulia; Pezard, Philippe; Edlman, Katriona

    2014-05-01

    One the major components of the EU-FP7 funded MUSTANG project is to conduct a highly controlled series of CO2 injection experiments, aimed at determining field values of key CO2 trapping mechanisms such as dissolution and residual trapping and to establish a comprehensive and consistent dataset for model validation. Progress achieved in Heletz includes the completion of the instrumentation of the injection well and the installation of the CO2 injection kit and the accompanying facilities on site, the conduction of hydraulic and tracer tests for the characterization of the hydro-geological properties of the reservoir and the starting of the first single well CO2 injection experiment. This paper presents the results of the hydraulic tests and water sampling, which have allowed refining our understanding of the reservoir hydrogeological behavior. This includes: 1) information on the chemical composition of the formation water; 2) a more representative estimation of the hydraulic conductivity and of the anisotropy; and 3) a relatively high content of suspended solids, which require and adequate abstraction policy. Additionally, it provides preliminary information on the monitoring of the single CO2 injection experiment.

  19. Groundwater cooling of a supercomputer in Perth, Western Australia: hydrogeological simulations and thermal sustainability

    NASA Astrophysics Data System (ADS)

    Sheldon, Heather A.; Schaubs, Peter M.; Rachakonda, Praveen K.; Trefry, Michael G.; Reid, Lynn B.; Lester, Daniel R.; Metcalfe, Guy; Poulet, Thomas; Regenauer-Lieb, Klaus

    2015-08-01

    Groundwater cooling (GWC) is a sustainable alternative to conventional cooling technologies for supercomputers. A GWC system has been implemented for the Pawsey Supercomputing Centre in Perth, Western Australia. Groundwater is extracted from the Mullaloo Aquifer at 20.8 °C and passes through a heat exchanger before returning to the same aquifer. Hydrogeological simulations of the GWC system were used to assess its performance and sustainability. Simulations were run with cooling capacities of 0.5 or 2.5 Mega Watts thermal (MWth), with scenarios representing various combinations of pumping rate, injection temperature and hydrogeological parameter values. The simulated system generates a thermal plume in the Mullaloo Aquifer and overlying Superficial Aquifer. Thermal breakthrough (transfer of heat from injection to production wells) occurred in 2.7-4.3 years for a 2.5 MWth system. Shielding (reinjection of cool groundwater between the injection and production wells) resulted in earlier thermal breakthrough but reduced the rate of temperature increase after breakthrough, such that shielding was beneficial after approximately 5 years pumping. Increasing injection temperature was preferable to increasing flow rate for maintaining cooling capacity after thermal breakthrough. Thermal impacts on existing wells were small, with up to 10 wells experiencing a temperature increase ? 0.1 °C (largest increase 6 °C).

  20. Relationship between the environmental and hydrogeological elements characterizing groundwater-dependent ecosystems in central Poland

    NASA Astrophysics Data System (ADS)

    Krogulec, Ewa; Zab?ocki, Sebastian

    2015-07-01

    Results are presented for a quantitative and qualitative analysis of the relationship between hydrogeological and environmental elements characterizing the areas of groundwater-dependent ecosytems (GDEs) located in the Kampinos National Park in central Poland. Statistical analysis was used to assess the seasonal and long-term variability of groundwater conditions. A geographic information system (GIS)-based model enabled the visualization of the test results. Objectification of spatial relationships between hydrogeological and environmental elements was carried out using factor analysis. The statistical analysis of groundwater levels in the period 1999-2013 confirmed the sequence of wet and dry years. The calculation enabled the determination of the range of groundwater-level changes, but no specific trends were observed with respect to these changes. Moreover, the widespread belief that the lowering of the water table in presented GDEs is due to anthropogenic pressure and climate change was not confirmed. The factor analysis showed that GDE areas are characterized by a considerable homogeneity of abiotic elements and locally occurring heterogeneous regions, mainly related to anthropogenic pressure. Dependency between the type of plant community and depth to the water table in the typical GDEs was not defined by the delimiting factors.

  1. Hydrogeological conditions of a crystalline aquifer: simulation of optimal abstraction rates under scenarios of reduced recharge.

    PubMed

    Yidana, Sandow Mark; Fynn, Obed Fiifi; Chegbeleh, Larry Pax; Nude, Prosper M; Asiedu, Daniel K

    2013-01-01

    A steady state numerical groundwater flow model has been calibrated to characterize the spatial distribution of a key hydraulic parameter in a crystalline aquifer in southwestern Ghana. This was to provide an initial basis for characterizing the hydrogeology of the terrain with a view to assisting in the large scale development of groundwater resources for various uses. The results suggest that the structural entities that control groundwater occurrence in the area are quite heterogeneous in their nature and orientation, ascribing hydraulic conductivity values in the range of 4.5 m/d to over 70 m/d to the simulated aquifer. Aquifer heterogeneities, coupled possibly with topographical trends, have led to the development of five prominent groundwater flowpaths in the area. Estimated groundwater recharge at calibration ranges between 0.25% and 9.13% of the total annual rainfall and appears to hold significant promise for large-scale groundwater development to support irrigation schemes. However, the model suggests that with reduced recharge by up to 30% of the current rates, the system can only sustain increased groundwater abstraction by up to 150% of the current abstraction rates. Prudent management of the resource will require a much more detailed hydrogeological study that identifies all the aquifers in the basin for the assessment of sustainable basin yield. PMID:24453882

  2. Waterborne toxoplasmosis investigated and analysed under hydrogeological assessment: new data and perspectives for further research

    PubMed Central

    Vieira, Flávia Pereira; Alves, Maria da Glória; Martins, Livia Mattos; Rangel, Alba Lucínia Peixoto; Dubey, Jitender Prakash; Hill, Dolores; Bahia-Oliveira/, Lilian Maria Garcia

    2015-01-01

    We present a set of data on human and chicken Toxoplasma gondii seroprevalence that was investigated and analysed in light of groundwater vulnerability information in an area endemic for waterborne toxoplasmosis in Brazil. Hydrogeological assessment was undertaken to select sites for water collection from wells for T. gondii oocyst testing and for collecting blood from free-range chickens and humans for anti-T. gondii serologic testing. Serologic testing of human specimens was done using conventional commercial tests and a sporozoite-specific embryogenesis-related protein (TgERP), which is able to differentiate whether infection resulted from tissue cysts or oocysts. Water specimens were negative for the presence of viable T. gondii oocysts. However, seroprevalence in free-range chickens was significantly associated with vulnerability of groundwater to surface contamination (p < 0.0001; odds ratio: 4.73, 95% confidence interval: 2.18-10.2). Surprisingly, a high prevalence of antibodies against TgERP was detected in human specimens, suggesting the possibility of a continuous contamination of drinking water with T. gondii oocysts in this endemic setting. These findings and the new proposed approach to investigate and analyse endemic toxoplasmosis in light of groundwater vulnerability information associated with prevalence in humans estimated by oocyst antigens recognition have implications for the potential role of hydrogeological assessment in researching waterborne toxoplasmosis at a global scale. PMID:26560984

  3. Constraining fault-zone hydrogeology through integrated hydrological and geoelectrical analysis

    NASA Astrophysics Data System (ADS)

    Ball, Lyndsay B.; Ge, Shemin; Caine, Jonathan Saul; Revil, André; Jardani, Abderrahim

    2010-08-01

    The hydrogeologic influence of the Elkhorn fault in South Park, Colorado, USA, is examined through hydrologic data supplemented by electrical resistivity tomography and self-potential measurements. Water-level data indicate that groundwater flow is impeded by the fault on the spatial scale of tens of meters, but the lack of outcrop prevents interpretation of why the fault creates this hydrologic heterogeneity. By supplementing hydrologic and geologic data with geoelectrical measurements, further hydrogeologic interpretation is possible. Resistivity profiles and self-potential data are consistent with the interpretation of increased fracturing within 70 m of the fault. Further interpretation of the fault zone includes the possibility of a vertical groundwater flow component in a fractured and relatively high permeability damage zone and one or more relatively low permeability fault cores resulting in a conduit-barrier behavior of the fault zone at the meter to tens-of-meters scale. Calculated hydraulic heads from the self-potential data reveal additional complexity in permeability structure, including a steeper hydraulic gradient immediately west of the interpreted fault trace than suggested by the well data alone.

  4. Relationship between the environmental and hydrogeological elements characterizing groundwater-dependent ecosystems in central Poland

    NASA Astrophysics Data System (ADS)

    Krogulec, Ewa; Zab?ocki, Sebastian

    2015-11-01

    Results are presented for a quantitative and qualitative analysis of the relationship between hydrogeological and environmental elements characterizing the areas of groundwater-dependent ecosytems (GDEs) located in the Kampinos National Park in central Poland. Statistical analysis was used to assess the seasonal and long-term variability of groundwater conditions. A geographic information system (GIS)-based model enabled the visualization of the test results. Objectification of spatial relationships between hydrogeological and environmental elements was carried out using factor analysis. The statistical analysis of groundwater levels in the period 1999-2013 confirmed the sequence of wet and dry years. The calculation enabled the determination of the range of groundwater-level changes, but no specific trends were observed with respect to these changes. Moreover, the widespread belief that the lowering of the water table in presented GDEs is due to anthropogenic pressure and climate change was not confirmed. The factor analysis showed that GDE areas are characterized by a considerable homogeneity of abiotic elements and locally occurring heterogeneous regions, mainly related to anthropogenic pressure. Dependency between the type of plant community and depth to the water table in the typical GDEs was not defined by the delimiting factors.

  5. Hydrogeological impacts of a railway tunnel in fractured Precambrian gneiss rocks (south-eastern Norway)

    NASA Astrophysics Data System (ADS)

    Kværner, Jens; Snilsberg, Petter

    2013-11-01

    Groundwater monitoring along the Romeriksporten tunnel, south-eastern Norway, provided an opportunity for studying the impacts of tunnelling on groundwater in fractured Precambrian gneiss rocks, and examining relations between bedrock hydrology, tectonic weakness zones and catchments. Tunnel leakage resulted in groundwater drawdown up to 35 m in weakness zones, converted groundwater discharge zones into recharge zones, and affected groundwater chemistry. The magnitude of drawdown and fluctuations in groundwater level differed between weakness zones, and varied with distance from the tunnel route, tunnel leakage, and recharge from catchments. Clear differences in groundwater level and fluctuation patterns indicated restricted groundwater flow between weakness zones. The groundwater drawdowns demonstrated coherent water-bearing networks to 180-m depth in faults and fracture zones. Similar groundwater levels with highly correlated fluctuations demonstrated hydraulic connectivity within fracture zones. Different groundwater drawdown and leakage in weakness zones with different appearance and influence of tectonic events demonstrated the importance of the geological history for bedrock hydrogeology. Water injection into the bedrock counteracted groundwater drawdowns. Even moderate leakage to underground constructions may lead to large groundwater drawdown in areas with small groundwater recharge. Hydrogeological interpretation of tectonic weakness zones should occur in the context of geological history and local catchment hydrology.

  6. Hydrogeological Conditions of a Crystalline Aquifer: Simulation of Optimal Abstraction Rates under Scenarios of Reduced Recharge

    PubMed Central

    Fynn, Obed Fiifi; Chegbeleh, Larry Pax; Nude, Prosper M.; Asiedu, Daniel K.

    2013-01-01

    A steady state numerical groundwater flow model has been calibrated to characterize the spatial distribution of a key hydraulic parameter in a crystalline aquifer in southwestern Ghana. This was to provide an initial basis for characterizing the hydrogeology of the terrain with a view to assisting in the large scale development of groundwater resources for various uses. The results suggest that the structural entities that control groundwater occurrence in the area are quite heterogeneous in their nature and orientation, ascribing hydraulic conductivity values in the range of 4.5?m/d to over 70?m/d to the simulated aquifer. Aquifer heterogeneities, coupled possibly with topographical trends, have led to the development of five prominent groundwater flowpaths in the area. Estimated groundwater recharge at calibration ranges between 0.25% and 9.13% of the total annual rainfall and appears to hold significant promise for large-scale groundwater development to support irrigation schemes. However, the model suggests that with reduced recharge by up to 30% of the current rates, the system can only sustain increased groundwater abstraction by up to 150% of the current abstraction rates. Prudent management of the resource will require a much more detailed hydrogeological study that identifies all the aquifers in the basin for the assessment of sustainable basin yield. PMID:24453882

  7. The geology and hydrogeology of Bear Creek Valley Waste Disposal Areas A and B

    SciTech Connect

    1984-05-01

    A study was undertaken of the Oil Landfarm and Burial Grounds A and B, which are three disposal sites within the Bear Creek Waste Disposal Area. The area is located west of the Y-12 plant, about 3 miles southwest of Oak Ridge, Tennessee. The purpose of this interim report is to present data collected at the Burial Grounds A and B, and to provide the results of hydrogeologic analyses. The Oil Landfarm geologic and hydrogeologic data and analyses have been submitted in a January 1984 interim report. The overall objectives of the study were to characterize the types and extent of wastes present and to define the occurrence and movement of ground water beneath the sites. The intention of this work is to provide criteria on which a design for containing the waste can be developed. Specific activities performed by Bechtel included: drilling for subsurface geologic data; installing monitoring wells; measuring permeability and ground-water flow directions; and collecting soil, sediment, surface- and ground-water, and liquid-waste samples for chemical analysis. Results are presented on the geology and ground waters.

  8. Hydrogeological research on intensively exploited deep aquifers in the `Loma de Úbeda' area (Jaén, southern Spain)

    NASA Astrophysics Data System (ADS)

    González-Ramón, Antonio; Rodríguez-Arévalo, Javier; Martos-Rosillo, Sergio; Gollonet, Javier

    2013-06-01

    The intensive use of groundwater for irrigation in the area of Úbeda (`Loma de Úbeda', Jaén, southern Spain) has transformed an area of traditionally rain-fed dry farmland into fields with some of the highest olive oil productivity in the world. Early hydrogeological research studies, initiated just after the beginning of the groundwater exploitation, revealed that the water was collected from three different overlapping aquifers occupying an area of over 1,100 km2, with the lower aquifers located at depths from 300 to over 700 m in an area of 440 km2. Multidisciplinary research, based on geological characterization, and piezometric, hydrochemical and isotopic data, has led to a conceptual model of functioning in this complex hydrogeological system. The proposed model allows for the identification of the recharge areas, and the discharge, which is at present mainly associated with the groundwater pumping. Areas of mixing of waters from the different aquifers and the main hydrogeochemical processes affecting groundwater quality are described.

  9. Hydrogeology of a low-level radioactive-waste disposal site near Sheffield, Illinois

    USGS Publications Warehouse

    Foster, J.B.; Erickson, J.R.; Healy, R.W.

    1984-01-01

    The Sheffield low-level radioactive-waste facility is located on 20 acres of rolling terrain 3 miles southwest of Sheffield, Illinois. The shallow hydrogeologic system is composed of glacial sediments. Pennsylvania shale and mudstone bedrock isolate the regional aquifers below from the hydrogeologic system in the overlying glacial deposits. Pebbly sand underlies 67 percent of the site. Two ground-water flow paths were identified. The primary path conveys ground water from the site to the east through the pebbly-sand unit; a secondary path conveys ground water to the south and east through less permeable material. The pebbly-sand unit provides an underdrain that eliminates the risk of water rising into the trenches. Digital computer model results indicate that the pebbly-sand unit controls ground-water movement. Tritium found migrating in ground water in the southeast corner of the site travels approximately 25 feet per year. A group of water samples from wells which contained the highest tritium concentrations had specific conductivities, alkalinities, hardness, and chloride, sulfate, calcium, and magnesium contents higher than normal for local shallow ground water. (USGS)

  10. Hydrogeologic framework of Antelope Valley and Bedell Flat, Washoe County, west-central Nevada

    USGS Publications Warehouse

    Berger, D.L.; Ponce, D.A.; Ross, W.C.

    2001-01-01

    Description of the hydrogeologic framework of Antelope Valley and Bedell Flat in west-central Nevada adds to the general knowledge of regional ground-water flow north of the Reno-Sparks metropolitan area. The hydrogeologic framework is defined by the rocks and deposits that transmit ground water or impede its movement and by the combined thickness of Cenozoic deposits. When data are lacking about the subsurface geology of an area, geophysical methods can be used to provide additional information. In this study, gravimetric and seismic-refraction methods were used to infer the form of structural features and to estimate the thickness of Cenozoic deposits in each of the two valleys. In Antelope Valley, the thickness of these deposits probably does not exceed about 300 feet, suggesting that ground-water storage in the basin-fill aquifer is limited. Beneath Bedell Flat is an elongated, northeast-trending structural depression in the pre-Cenozoic basement; the maximum thickness of Cenozoic deposits is about 2,500 feet beneath the south-central part of the valley. Shallow ground water in the northwest corner of Bedell Flat may be a result of decreasing depth to the pre-Cenozoic basement.

  11. A hydrogeological type section for the Duna-Tisza Interfluve, Hungary

    NASA Astrophysics Data System (ADS)

    Mádl-Sz?nyi, Judit; Tóth, József

    2009-06-01

    The Duna-Tisza Interfluve, Hungary has an agricultural economy but is plagued by severe problems of soil and wetland salinization despite 200 years of intensive research. The study’s objective was to determine the origin of salts and the mechanisms of salinity distribution. To this end, flow-patterns and chemistry of groundwater were evaluated in a 100 km × 65 km area, with emphasis on the Kolon- and Kelemenszék Lakes region. The lakes are located 13 km apart and have chemically contrasting water and soil types. Two groundwater flow-domains were identified: a gravity-drive meteoric fresh water and an over-pressured deeper domain of saline water. The waters are channeled by a highly permeable gravel aquifer to the surface and may merge near Kelemenszék Lake, causing it to be saline. Kolon Lake receives meteoric groundwater only, hence its fresh chemical character. The cross-formational ascent of the deep waters, combined with the gravitational systems’ geometry and the flow-channeling effect of the near-surface rocks, explains the contrasting chemistry between lakes, and the origin and pattern of soil salinization. The scheme is proposed as a generally valid hydrogeological profile for the interfluve, and has been named the Duna-Tisza Interfluve Hydrogeological Type Section.

  12. Characterisation of the hydrogeology of the Augustus River catchment, Western Australia

    NASA Astrophysics Data System (ADS)

    Wilkes, Shane M.; Clement, T. Prabhakar; Otto, Claus J.

    Understanding the hydrogeology of weathered rock catchments is integral for the management of various problems related to increased salinity within the many towns of Western Australia. This paper presents the results of site characterisation investigations aimed at improving the overall understanding of the hydrogeology of the southern portion of the Augustus River catchment, an example of a weathered rock catchment. Site data have highlighted the presence of both porous media aquifers within the weathered profile and fractured rock aquifers within the basement rocks. Geophysical airborne surveys and other drilling data have identified a large number of dolerite dykes which crosscut the site. Fractured quartz veins have been found along the margins of these dolerite dykes. Detailed groundwater-level measurements and barometric efficiency estimates indicate that these dolerite dykes and fractured quartz veins are affecting groundwater flow directions, promoting a strong hydraulic connection between all aquifers, and also influencing recharge mechanisms. The hydrogeological significance of the dolerite dykes and fractured quartz veins has been assessed using a combination of high-frequency groundwater-level measurements (30-min sampling interval), rainfall measurements (5-min sampling interval) and barometric pressure fluctuations (30-min sampling interval). A conceptual model was developed for describing various hydrogeological features of the study area. The model indicates that fractured quartz veins along the margins of dolerite dykes are an important component of the hydrogeology of the weathered rock catchments. Comprendre l'hydrogéologie des bassins en roches altérées est essentiel pour la gestion de différents problèmes liés à l'augmentation de la salinité dans de nombreuses villes d'Australie occidentale. Cet article présente les résultats d'études de caractérisation de sites conduites pour améliorer la compréhension de l'hydrogéologie de la partie sud du bassin de la rivière Augustus, exemple de bassin en roches altérées. Les données concernant le site ont mis en évidence la présence simultanée d'aquifères poreux dans le profil d'altération et d'aquifères de roches fracturées dans le socle. Des campagnes de géophysique aéroportée et d'autres données de forages ont identifié de très nombreux dykes de dolérite traversant le site. Des veines de quartz fracturées ont été trouvées aux marges de ces dykes de dolérite. Des mesures détaillées de niveau des nappes et des estimations des effets barométriques indiquent que ces dykes de dolérite et les veines de quartz fracturées affectent les directions d'écoulement souterrain, favorisant une forte connexion hydraulique entre tous ces aquifères, et influençant également les mécanismes de recharge. La signification hydrogéologique des dykes de dolérite et des veines de quartz fracturées a été analysée en combinant des mesures à haute fréquence du niveau des nappes (toutes les 30 min), de la pluie (toutes les 5 min) et des variations de la pression barométrique (toutes les 30 min). Un modèle conceptuel a été établi pour décrire les différents phénomènes hydrogéologiques de la région étudiée. Ce modèle indique que les veines de quartz aux marges des dykes de dolérite sont une importante composante de l'hydrogéologie des bassins en roches altérées. Entender la hidrogeología de cuencas con rocas meteorizadas es esencial para gestionar diversos problemas relacionados con el incremento de salinidad en muchas ciudades de Australia Occidental. Este artículo presenta los resultados obtenidos en la caracterización de varios emplazamientos con el fin de mejorar el conocimiento general de la hidrogeología en la zona sur de la cuenca del Río Augustus, que sirve como ejemplo de cuenca en rocas meteorizadas. Los datos de campo resaltan la presencia tanto de medios acuíferos porosos dentro del perfil meteorizado como de acuíferos en rocas fracturadas dentro de la roca fresca. Los registros geofísicos aéreos y

  13. Selected hydrogeologic data for the Inyan Kara, Minnekahta, Minnelusa, Madison, and Deadwood aquifers in the Black Hills area, South Dakota

    USGS Publications Warehouse

    Galloway, J.M.

    1999-01-01

    This report presents selected hydrogeologic data on wells and springs in the Inyan Kara, Minnekahta, Minnelusa, Madison, and Deadwood aquifers in the Black Hills area of western South Dakota. The data were used to create potentiometric maps for these five aquifers.

  14. Geologic and Hydrogeologic Information for a Geodatabase for the Brazos River Alluvium Aquifer, Bosque County to Fort Bend County, Texas

    USGS Publications Warehouse

    Shah, Sachin D.; Houston, Natalie A.

    2007-01-01

    During July-October 2006, the U.S. Geological Survey (USGS), in cooperation with the Texas Water Development Board (TWDB), developed geologic and hydrogeologic information for a geodatabase for use in development of a Groundwater Availability Model (GAM) of the Brazos River alluvium aquifer along the Brazos River from Bosque County to Fort Bend County, Texas. The report provides geologic and hydrogeologic information for a study area that encompasses the Brazos River alluvium aquifer, a 1/2-mile-wide lateral buffer surrounding the aquifer, and the rocks immediately underlying the aquifer. The geodatabase involves use of a thematic approach to create layers of feature data using a geographic information system. Feature classes represent the various types of data that are keyed to spatial location and related to one another within the geodatabase. The 1/2-mile-wide buffer surrounding the aquifer was applied to include data from wells constructed primarily in alluvium but outside the boundary of the Brazos River alluvium aquifer. A 1/2- by 1/2-mile grid was generated on the study area to facilitate uniform distribution of data for eventual input into the GAM. Data were compiled primarily from drillers and borehole geophysical logs from government agencies and universities, hydrogeologic sections and maps from published reports, and agency files. The geodatabase contains 450 points with geologic data and 280 points with hydrogeologic data.

  15. Calendar year 1995 groundwater quality report for the Bear Creek Hydrogeologic Regime, Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    SciTech Connect

    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.

  16. Extraterrestrial hydrogeology

    NASA Astrophysics Data System (ADS)

    Baker, Victor R.; Dohm, James M.; Fairén, Alberto G.; Ferré, Ty P. A.; Ferris, Justin C.; Miyamoto, Hideaki; Schulze-Makuch, Dirk

    2005-03-01

    Subsurface water processes are common for planetary bodies in the solar system and are highly probable for exoplanets (planets outside the solar system). For many solar system objects, the subsurface water exists as ice. For Earth and Mars, subsurface saturated zones have occurred throughout their planetary histories. Earth is mostly clement with the recharge of most groundwater reservoirs from ample precipitation during transient ice- and hot-house conditions, as recorded through the geologic and fossilized records. On the other hand, Mars is mostly in an ice-house stage, which is interrupted by endogenic-driven activity. This activity catastrophically drives short-lived hydrological cycling and associated climatic perturbations. Regional aquifers in the Martian highlands that developed during past, more Earth-like conditions delivered water to the northern plains. Water was also cycled to the South Polar Region during changes in climate induced by endogenic activity and/or by changes in Mars' orbital parameters. Venus very likely had a warm hydrosphere for hundreds of millions of years, before the development of its current extremely hot atmosphere and surface. Subsequently, Venus lost its hydrosphere as solar luminosity increased and a run-away moist greenhouse took effect. Subsurface oceans of water or ammonia-water composition, induced by tidal forces and radiogenic heating, probably occur on the larger satellites Europa, Ganymede, Callisto, Titan, and Triton. Tidal forces operating between some of the small bodies of the outer solar system could also promote the fusion of ice and the stability of inner liquid-water oceans. Les processus de subsurface impliquant l'eau sont communs pour les corps planétaires du système solaire et sont très probables sur les exoplanètes (planètes en dehors du système solaire). Pour plusieurs objets du systèmes solaire, l'eau de subsurface est présente sous forme de glace. Pour la Terre et Mars, les zones saturées de subsurface apparaissent à travers toute leur histoire planétaire. La Terre est particulièrement clémente avec la recharge des réservoirs, avec de amples précipitations, des conditions glaciaires et de fortes chaleurs, comme l'atteste les enregistrements géologiques et paléontologiques. D'un autre côté, Mars se trouve dans une phase essentiellement glaciaire, qui est interrompue par des activités contraintes par les phénomènes endogéniques. Cette activité conduit de manière catastrophique à des cycles hydrologiques et à des perturbations climatiques brutaux. Les aquifères régionaux dans les haute terres martiennes qui se sont formés dans des conditions similaires aux conditions terrestres, alimentent les plaines du Nord. L'eau a également été déplacée vers le Pôle Sud martien durant des changements marqués par une forte activité endogénique et une modification des paramètres de l'orbite de Mars. Venus possèdait vrais emblablement une hydrosphère chaude durant des millions d'année, avant le développement de son atmosphère et sa surface particulièrement chaude. Par après Venus a perdit son hydrosphère alors que la luminosité solaire augmentait et qu'une humidité liée à un effet de serre s'installait. Les océans de subsurface d'eau ou d'eau ammoniacale, induits par les forces de marée et le chauffage radiogénique, apparaissent probablement sur les satellites les plus importants (Europa, Ganymede, Callisto, Titan, Triton). Les forces de marée entre les petits corps externes du système solaire peuvent également occasionner la fusion de glace et la stabilité des océans internes d'eau liquide. Los procesos hídricos subsuperficiales son comunes en cuerpos planetarios del sistema solar y son altamente probables para exoplanetas (planetas fuera del sistema solar). Para muchos cuerpos del sistema solar, el agua subsuperficial existe como hielo. Para la Tierra y Marte han ocurrido zonas saturadas subsuperficiales a través de sus historias planetarias. La Tierra es principalmente generosa con la recarga de la mayoría de rese

  17. Natural and Artificial (fluorescent) Tracers to Characterise Hydrogeological Functioning and to Protect Karst Aquifers

    NASA Astrophysics Data System (ADS)

    Andreo, B.

    2013-12-01

    Bartolomé Andreo; andreo@uma.es Co-workers: Matías Mudarra, Ana Isabel Marín and Juan Antonio Barberá Centre of Hydrogeology and Department of Geology. University of Malaga. http://cehiuma.uma.es/ The hydrogeological functioning and response of karst aquifers can be determined by the combined use of natural hydrogeochemical tracers, especially Total Organic Carbon (TOC) and intrinsic fluorescence of water, together with artificial (fluorescent) tracers; all them under the same hydrodynamic conditions. Sharp and rapid variations in discharge, temperature, electrical conductivity and water chemistry, particularly of natural tracers of infiltration (TOC, intrinsic fluorescence and NO3-) recorded in karst spring waters suggest the existence of a conduit flow system, with rapid flows and very short transit times from the surface to the springs. This is in agreement with the evidences obtained from breakthrough curves of fluorescent dye tracers. However, each type of tracer provides information about different aspects of the system in response to rainfall: natural tracers show the global response of the entire recharge area, while dye tracers reflect the response to concentrated recharge from specific points on the surface (karst swallow holes). Recent experiences on time lags between maximum concentrations of natural (especially TOC and intrinsic fluorescence) and artificial tracers has demonstrated that the global system response is faster and more sensitive than that produced from infiltration concentrated at a single point on the surface, even in karst sinkholes. Both natural and dye tracers permit to estimate response and transit times of water through the karst, but flow velocities can only be quantified using artificial tracers. These findings are crucial for water resources management and protection, with particular emphasis in the functioning of the aquifer and the different rates of response to input signals. Analysis of the responses obtained by natural tracers of infiltration (global system response) and artificial tracers (single response) in karst waters has revealed the usefulness and complementarily of both techniques for characterising the hydrogeological functioning of karst aquifers and, even more important, for validating contamination vulnerability mapping in these medium. In recent decades, several methods have been developed for such vulnerability mapping, but little progress has been made in validating their results. This validation is essential for the adequate protection of water resources in karst media, as has been shown in recent research.

  18. An Attempt of Hydrogeological Classification of Fault Zones in Karst Areas

    NASA Astrophysics Data System (ADS)

    Bauer, Helene; Decker, Kurt

    2014-05-01

    Around 60% of Vienna`s drinking water originates in the Hochschwab plateau (Eastern Alps, Austria). The hydrogeology (groundwater storage and flow) of the Hochschwab is essentially governed by karstified, large-scale faults. Previous work has shown that faults that formed during the Oligocene/L. Miocene lateral extrusion of the Eastern Alps act as groundwater pathways draining the karst massif preferably in E-W-direction. However, further analysis of flow processes in karstified aquifers requires hydrogeological relevant data from natural fault zones. We investigated E- to ENE- striking strike-slip faults in limestones and dolomites of the Wetterstein Fm. in terms of potential permeability properties that result from structural composition and fault rock content. Using the standard fault core-damage zone model, we analyzed fault rock characteristics and volumes at the fault cores and connective fracture networks surrounding faults in the damage zones. Special attention has been drawn to fracture densities and the spatial extent of fracture networks. Small-scale fractures are generally assumed to carry most of the effective porosity and have a great influence on the permeability of a fault zone. Therefore, we established a classification scheme and measuring method that provides semi-quantitative estimates of the density and abundance of small-scale fractures by using scanning line techniques to quantify the total joint surface in a volume of rock (m² joint surfaces per m³ rock). This easily applicable method allows to generate fracture density data for the entire damage zones (over tens of meters) and thus to enhance the understanding of permeability properties of damage zones. The field based data is supported by effective porosity and permeability measurements of fractured wall rock and fault rock samples. Different fault rock categories turned out to have complex poro/perm properties due to differences in grain sizes, matrix content, cementation and fracturing. In summary, the volume of fault rocks seems to be a function of size and displacement of the faults. Fracture densities in damage zones shows gradual increase from fault zone margins towards fault cores and significant asymmetries. Highest fracture densities with nearly isotropic fracture networks are often located adjacent to the fault core boundary and seem to be depending again on fault size/displacement. More research has to be done, but the presented results provide a useful base for further applications in hydrogeological modelling.

  19. Estimation of regional hydrogeological properties for use in a hydrologic model of the Chesapeake Bay watershed

    NASA Astrophysics Data System (ADS)

    Seck, A.; Welty, C.

    2012-12-01

    Characterization of subsurface hydrogeologic properties in three dimensions and at large scales for use in groundwater flow models can remain a challenge owing to the lack of regional data sets and scatter in coverage, type, and format of existing small-scale data sets. This is the case for the Chesapeake Bay watershed, where numerous studies have been carried out to quantify groundwater processes at small scales but limited information is available on subsurface characteristics and groundwater fluxes at regional scales. One goal of this work is to synthesize disparate information on subsurface properties for the Chesapeake Bay watershed for use in a 3D integrated ParFlow model over an area of 400,000 km2 with a horizontal resolution of 1 km and a vertical resolution of 5 m. We combined different types of data at various scales to characterize hydrostratigraphy and hydrogeological properties. The conceptual hydrogeologic model of the study area is composed of two major regions. One region extends from the Valley and Ridge physiographic province south of New York to the Piedmont physiographic province in Maryland and Virginia. This region is generally characterized by fractured rock overlain by a mantle of regolith. Soil thickness and hydraulic conductivity values were obtained from the U.S. General Soil Map (STATSGO2). Saprolite thickness was evaluated using casing depth information from well completion reports from four state agencies. Geostatistical methods were used to generalize point data to the model extent and resolution. A three-dimensional hydraulic conductivity field for fractured bedrock was estimated using a published national map of permeability and depth- varying functions from literature. The Coastal Plain of Maryland, Virginia, Delaware and New Jersey constitutes the second region and is characterized by layered sediments. In this region, the geometry of 20 aquifers and confining units was constructed using interpolation of published contour maps of aquifer altitudes and confining unit thicknesses. Areas of outcrop of the aquifers and confining units were corrected using the USGS HydroSHEDS land surface topography dataset. Ongoing work includes the use of this constructed dataset in the hydrologic model to determine regional groundwater flow paths and travel times.

  20. Constraining Fault-Zone Hydrogeology through Integrated Hydrological and Geoelectrical Analysis

    NASA Astrophysics Data System (ADS)

    Ball, L. B.; Ge, S.; Caine, J. S.; Revil, A.; Jardani, A.

    2009-12-01

    Permeability heterogeneity introduced by faults can substantially impact groundwater flow. However, because faults are often poorly exposed at the surface, the architecture of the fault is frequently unobservable and understanding the hydrologic impact of a specific fault is particularly challenging. To improve our ability to estimate fault-zone permeability structure and to document the impact of a major, inactive fault on groundwater flow, we supplemented traditional hydrogeologic measurements with electrical resistivity and self-potential data at the Elkhorn fault in South Park, Colorado. Water levels taken in four wells across the fault indicate that permeability generally decreases from the fractured granitic hanging wall to the sedimentary footwall. Permeability estimates from slug tests and single-well pumping tests are consistent with this decreasing pattern and vary over a few orders of magnitude across the site. However, the lack of outcrop or detailed documentation of the spatial extent and nature of the fault zone hinders our ability to understand these hydrogeologic data in the structural context of the fault. Resistivity tomography was used in combination with available geologic maps, drill-core lithologic descriptions, and water-level/permeability data to determine the fault location and geometry. Self-potential measurements co-located with the resistivity data were used to interpret groundwater-flow patterns in the immediate vicinity of the fault and to create a high-resolution interpretation of the hydraulic-head distribution in transects across the fault. The hydrogeologic measurements and geoelectrical data were used to make interpretations about the presence and permeability structure of fault-zone components at the meter to tens-of-meters scale. Electrical resistivity tomography profiles reveal that the fault zone may contain increased fracturing in a damage zone in the 70 meters surrounding the fault and that three of the wells likely fall within this zone. A slight departure from the general self-potential gradient supports the possibility of a vertical flow component in an anisotropic damage zone or that one or more fault cores are present that locally disturb groundwater flow. Self-potential data further suggest that the general groundwater-flow direction shifts southward several degrees across the fault. Reconstruction of the water table from the self-potential measurements suggests that the initial change in hydraulic gradient between the hanging wall and footwall is slightly steeper than suggested by the well data alone, further supporting the interpretation of a relatively low permeability fault core. The permeability estimates from hydraulic testing and the interpretation of geoelectrical data suggest that the Elkhorn fault behaves as a combined conduit-barrier to groundwater flow at the scale of meters to tens-of-meters.

  1. The hydrological and the hydrogeological framework of the Lottenbachtal, Bochum, Germany

    NASA Astrophysics Data System (ADS)

    Alhamed, Mohammad

    2014-11-01

    This study was performed to investigate the hydrological and the hydrogeological framework of the Lottenbachtal, Germany. Long-term climatic data were statistically analyzed, water and soil samples were collected and analyzed, stream flow discharge was measured and separated, the hydrological balance of this catchment was calculated and a hydrological and hydrogeological conceptual model was constructed. The study area is characterized mainly by the precipitation value ranged between 0.1 and 5 mm/day. The actual evapotranspiration constitutes 31.90 % of the total precipitation, the direct surface runoff constitutes 61.04 %, the soil storage constitutes 3 % and the groundwater recharge of the Lottenbachtal constitutes only 4 % of the total precipitation. The Lottenbachtal has largely affected the diversity of the land use, which includes forests, arable areas, abandoned coal mines and settlement areas. The soil of the forested area is represented by relatively high acidic conditions and relatively high sulfate concentrations, while the soil of the arable areas is represented by near-neutral conditions associated with relatively high concentrations of nutrients and other chemical elements (calcium, magnesium, sodium, potassium, chloride, sulfate, nitrate). The settlement areas are characterized by huge blocks of concrete and backfills, which are rich in calcium and magnesium carbonates. The effects of this diversity in the land use on groundwater and surface water quality resulting by leaching the chemical elements from the soil covers and the other materials. These effects are represented by the following complex water types of Ca-Na-Mg-Cl-SO4-HCO3, Ca-Mg-HCO3-SO4, Ca-Na-Mg-Cl-SO4, Ca-Na-Mg-Cl-SO4 and Ca-HCO3, which represent the diversity of the flow paths of the water as well as to mixing processes. The diversity of the land use also affected the physical hydrological-hydrogeological characteristics of the study area by increasing the direct surface runoff and decreasing the groundwater recharge. The impervious surfaces of the settlement areas and the low hydraulic conductivities of the soil covers are responsible for these conditions.

  2. Geologic framework and hydrogeologic characteristics of the Edwards aquifer outcrop (Barton Springs segment), northeastern Hays and southwestern Travis Counties, Texas

    USGS Publications Warehouse

    Small, Ted A.; Hanson, John A.; Hauwert, Nico M.

    1996-01-01

    The hydrogeologic subdivisions within the Barton Springs segment of the Edwards aquifer outcrop in northeastern Hays and southwestern Travis Counties generally are porous and permeable. The most porous and permeable appear to be hydrogeologic subdivision VI, the Kirschberg evaporite member of the Kainer Formation; and hydrogeologic subdivision III, the leached and collapsed members, undivided, of the Person Formation. Hydrogeologic subdivision II, the cyclic and marine members, undivided, of the Person Formation, also is quite porous and permeable in Hays County. The porosity of the rocks in the Edwards aquifer outcrop is related to depositional or diagenetic elements along specific stratigraphic horizons (fabric selective) and to dissolution and structural elements that can occur in any lithostratigraphic horizon (not fabric selective). Permeability depends on the physical properties of the rock such as pore size, shape, distribution, fissuring, dissolution, and interconnection of pores and vugs. The Edwards aquifer rocks that crop out in the Barton Springs segment of the Edwards aquifer generally have the same lithologic characteristics as the Edwards aquifer rocks that crop out in Comal and southwestern Hays Counties. However, in the northeastern part of the segment in Travis County, the rock unit that is apparently equivalent to the basal nodular member of the Kainer Formation is called the Walnut Formation. Because the units appear to be stratigraphically and lithologically equivalent, the basal nodular member is used instead of the Walnut Formation for this report. Essentially all of hydrogeologic subdivision II, which is about 70 feet thick in Hays County, is missing in Travis County. In the Barton Springs segment of the Edwards aquifer, the aquifer probably is most vulnerable to surface contamination in the rapidly urbanizing areas on the Edwards aquifer outcrop. Contamination can result from spills or leakage of hazardous materials; or runoff on the intensely faulted and fractured, karstic limestone outcrops characteristic of the recharge zone.

  3. Geophysical Interpretations of the Southern Espanola Basin, New Mexico, That Contribute to Understanding Its Hydrogeologic Framework

    USGS Publications Warehouse

    Grauch, V.J.S.; Phillips, Jeffrey D.; Koning, Daniel J.; Johnson, Peggy S.; Bankey, Viki

    2009-01-01

    The southern Espanola basin consists of a westward- and northward-thickening wedge of rift fill, composed primarily of Santa Fe Group sediments, that serves as an important aquifer for the city of Santa Fe and surrounding areas. Detailed aeromagnetic surveys were flown to better understand ground-water resources in this aquifer. This report presents a synthesis of these data with gravity data and other constraints. The interpretations were accomplished using qualitative interpretation, state-of-art data analysis techniques, and two- and three-dimensional modeling. The results depict the presence of and depth to many geologic features that have hydrogeologic significance, including shallow faults, different types of igneous units, and basement rocks. The results are presented as map interpretations, geophysical profile models, and a digital surface that represents the base and thickness of Santa Fe Group sediments, as well as vector files of some volcanic features and faults.

  4. Geophysical framework of the southwestern Nevada volcanic field and hydrogeologic implications

    USGS Publications Warehouse

    Grauch, V.J.; Sawyer, David A.; Fridrich, Chris J.; Hudson, Mark R.

    1999-01-01

    Gravity and magnetic data, when integrated with other geophysical, geological, and rock-property data, provide a regional framework to view the subsurface geology in the southwestern Nevada volcanic field. The region has been loosely divided into six domains based on structural style and overall geophysical character. For each domain, the subsurface tectonic and magmatic features that have been inferred or interpreted from previous geophysical work has been reviewed. Where possible, abrupt changes in geophysical fields as evidence for potential structural lithologic control on ground-water flow has been noted. Inferred lithology is used to suggest associated hydrogeologic units in the subsurface. The resulting framework provides a basis for investigators to develop hypotheses from regional ground-water pathways where no drill-hole information exists.

  5. Hydrogeologic data from a shallow flooding demonstration project, Twitchell Island, California, 1997-2001

    USGS Publications Warehouse

    Gamble, James M.; Burow, Karen R.; Wheeler, Gail A.; Hilditch, Robert; Drexler, Judy Z.

    2003-01-01

    Data were collected during a study to determine the effects of continuous shallow flooding on ground-water discharge to an agricultural drainage ditch on Twitchell Island, California. The conceptual model of the hydrogeologic setting was detailed with soil coring and borehole-geophysical logs. Twenty-two monitoring wells were installed to observe hydraulic head. Ten aquifer slug tests were done in peat and mineral sediments. Ground-water and surface-water temperature was monitored at 14 locations. Flow to and from the pond was monitored through direct measurement of flows and through the calculation of a water budget. These data were gathered to support the development of a two-dimensional ground-water flow model. The model will be used to estimate subsurface discharge to the drainage ditch as a result of the pond. The estimated discharge will be used to estimate the concentrations of DOC that can be expected in the ditch.

  6. A hydrogeological conceptual approach to study urban groundwater flow in Bucharest city, Romania

    NASA Astrophysics Data System (ADS)

    Boukhemacha, Mohamed Amine; Gogu, Constantin Radu; Serpescu, Irina; Gaitanaru, Dragos; Bica, Ioan

    2015-05-01

    Management of groundwater systems in urban areas is necessary and can be reliably performed by means of mathematical modeling combined with geospatial analysis. A conceptual approach for the study of urban hydrogeological systems is presented. The proposed approach is based on the features of Bucharest city (Romania) and can be adapted to other urban areas showing similar characteristics. It takes into account the interaction between groundwater and significant urban infrastructure elements that can be encountered in modern cities such as subway tunnels and water-supply networks, and gives special attention to the sewer system. In this respect, an adaptation of the leakage factor approach is proposed, which uses a sewer-system zoning function related to the conduits' location in the aquifer system and a sewer-conduits classification function related to their structural and/or hydraulic properties. The approach was used to elaborate a single-layered steady state groundwater flow model for a pilot zone of Bucharest city.

  7. Hydrogeology of Puerto Rico and the outlying islands of Vieques, Culebra, and Mona

    USGS Publications Warehouse

    Gómez-Gómez, Fernando; Rodríguez-Martínez, Jesús; Santiago, Marilyn

    2014-01-01

    The availability of hydrogeologic maps for Puerto Rico and the outlying islands of Vieques, Culebra, and Mona are important to hydrogeologists, groundwater specialists, and water resource managers and planners. These maps, in combination with the report, serve as a source of information to all users by providing basic hydrogeologic and hydrologic knowledge in a concise illustrated format. Puerto Rico and the outlying islands cover a total area of 8,927 square kilometers (km2). Of this total area, about 3,500 km2 are underlain by hydrogeologic units that are classified as intergranular or fissured. These hydrogeologic units form the principal aquifer systems throughout Puerto Rico and the outlying islands. In Puerto Rico, the most extensive and intensely developed aquifers are the North Coast Limestone aquifer system and the South Coastal Alluvial Plain aquifer system. Withdrawals from these two aquifer systems constitute nearly 70 percent of the total groundwater withdrawn in Puerto Rico. The spatial extent of the North Coast Limestone aquifer system is about 2,000 km2. Within this aquifer system, groundwater development is greatest in the 800-km2 area between the Río Grande de Arecibo and the Río de la Plata. This also is the area for which concern is the highest regarding the future use of groundwater as a primary source of water for domestic and industrial use. With an estimated withdrawal of 280,000 cubic meters per day (m3/d), groundwater constituted the principal source of water within this area providing 100 percent of the water for self-supplied industries and about 85 percent for public water supplies in 1985. By 2005, groundwater withdrawals decreased to 150,000 m3/d. The spatial extent of the South Coastal Alluvial Plain aquifer system is about 470 km2. The estimated consumptive groundwater withdrawal from the aquifer system was 190,000 m3/d in 1980 and 170,000 m3/d in 2005. About 60 percent and 40 percent of the groundwater withdrawal from the South Coastal Alluvial Plain aquifer system was used for public water supply and irrigation, respectively. In the outlying islands of Vieques, Culebra, and Mona, only Vieques is underlain by aquifers of any local importance. The Resolución and Esperanza aquifers underlie an area covering 16 km2 on the island of Vieques. Prior to 1978 when an underwater public water-supply pipeline connecting Vieques to the main island of Puerto Rico was completed, groundwater withdrawal from the two aquifers was as much as 2,500 m3/d. Groundwater withdrawals in Vieques island in 2005 were estimated at less than 100 m3/d. The potential development of relatively untapped groundwater resources in Puerto Rico is limited to the Río Grande de Añasco valley and the Río Culebrinas valley in the western part of the island and to the Río Grande de Arecibo part of the North Coast Limestone aquifer system. In general, the North Coast Limestone and the South Coastal Alluvial Plain aquifer systems, which are the two principal groundwater-flow systems in Puerto Rico, show evidence of aquifer overdraft as indicated by regional increases in concentrations of dissolved solids. Optimization of withdrawals through conjunctive use of both surface-water and groundwater sources and by instituting water conservation measures has the greatest potential to ensure the continued use of groundwater resources. In support of these efforts, programs also could be implemented to improve database information regarding groundwater withdrawals and the contribution of surface-water diversions to surface-water flow, especially within the southern coastal plain of Puerto Rico.

  8. Hydrogeologic characterization of the Coldwater Spring recharge area, Calhoun County, Alabama

    USGS Publications Warehouse

    Kidd, Robert E.

    2001-01-01

    The complex ground-water flow in the Coldwater Spring aquifer system is the result of complicated geologic structures, porous media flow within the shallow unconsolidated zone, conduit flow in the karst bedrock aquifers, and discontinuities in hydrogeologic units caused by faulting. Recharge water in the unconsolidated zone percolates slowly to the underlying bedrock aquifer. The bedrock aquifer includes fractured zones in the Chilhowee Group and solution features in the Shady Dolomite, Conasauga Formation, Knox Groud, and Newala and Little Oak Limestones. Ground-water movement in the shallow unconsolidated zone roughly follows the topographic surface as it moves deeper into the ground-water system. Ground water flowing south through the bedrock aquifers is bloced by less permeable rocks in the area of the Jacksonville Fault; and possibly moves south and west along the fault to discharge at Coldwater Spring. The recharge area for Coldwater Spring encompasses the recharge areas of the shallow unconsolidated zone and the bedrock aquifers.

  9. East Chestnut Ridge hydrogeologic characterization: A geophysical study of two karst features

    SciTech Connect

    Not Available

    1991-01-01

    Permitting and site selection activities for the proposed East Chestnut Ridge landfill, located on the Oak Ridge Reservation, have required additional hydrogeologic studies of two karst features. Geophysical testing methods were utilized for investigating these karst features. The objectives of the geophysical testing was to determine the feasibility of geophysical techniques for locating subsurface karst features and to determine if subsurface anomalies exist at the proposed landfill site. Two karst features, one lacking surface expression (sinkhole) but with a known solution cavity at depth (from previous hydrologic studies), and the other with surface expression were tested with surface geophysical methods. Four geophysical profiles, two crossing and centered over each karst feature were collected using both gravimetric and electrical resistivity techniques.

  10. Combined geophysical and petrophysical characterization to support a hydrogeological model of a coastal environment

    NASA Astrophysics Data System (ADS)

    Burschil, Thomas; Wiederhold, Helga; Scheer, Wolfgang; Kirsch, Reinhard; Krawczyk, Charlotte M.

    2014-05-01

    Global warming affects the water cycle by changing precipitation/evaporation and raising sea level. Especially groundwater systems in sensitive environments, such as coastal areas or barrier islands, have to be evaluated with respect to the potential reduction of water quality, e.g. salinization by saltwater intrusion (Hinsby et al., 2012). To assess these hazards using groundwater modeling we need a strong base of hydraulic and hydrogeological information. The use of integrated geophysical methods, in combination with a petrophysical characterization, provides a reliable architecture for groundwater modeling. Within the EU-project CLIWAT, we investigated the hydrogeological situation of the North Sea island of Föhr in Schleswig-Holstein (Germany). The island was mainly formed during glaciations in Pleistocene Series, especially Saalian and Weichselian Stages. These deposits remain as a Geest core in the southern central part, and house a freshwater lens that is used for the local water supply. To investigate the architecture of the fresh water lens, we carried out several surveys with airborne electromagnetic (AEM), seismic reflection, and borehole methods. To enhance the AEM resistivity model we inverted the data with a-priori constraints from seismic reflections (Burschil et al., 2012a). This constrained inversion leads to, among other things, a separation of two aquifers by resistivity data. Additionally, from borehole logs, vertical seismic profiles (VSP), and nearby AEM inversion point models we are able to petrophysically characterize different lithological categories regarding resistivity and seismic velocity. Subsurface glacial structures, e.g. buried valleys and a push moraine complex, are mapped down to 150 m below sea level. Below this rather horizontal features indicate Tertiary layers. Geophysically determined petrophysical values were correlated with lithological categories to enhance the interpretation of geophysical data. In this way, we expose the complex disorder of Pleistocene till and sand, as well as Pliocene sand and Miocene clay, in the uppermost 150 m. All results are implemented in a hydrogeological 3D model as base for groundwater modeling and to forecast climate change effects (Burschil et al., 2012b). References Burschil, T., H. Wiederhold & E. Auken (2012a): Seismic results as a-priori knowledge for airborneTEM data inversion - a case study. J. Appl. Geophys., 80, 121-128, doi: 10.1016/j.jappgeo.2012.02.003. Burschil, T., W. Scheer, R. Kirsch & H. Wiederhold (2012b): Hydrogeological characterisation of a glacially affected barrier island - the North Frisian Island of Föhr. Hydrol. Earth Syst. Sci., 16, 3485-3498. Hinsby, K., E., Auken, G.H.P. Oude Essink, P. de Louw, F. Jørgensen, B. Siemon, T.O. Sonnenborg, A. Vandenbohede, H. Wiederhold, A. Guadagnini & J. Carrera (Eds.) (2012): Assessing the impact of climate change for adaptive water management in coastal regions. Hydrology and Earth System Sciences, 17, http://www.hydrol-earth-syst-sci.net/specialissue149.html.

  11. Field Trip 5: HYDROGEOLOGY OF BEER AND WINE IN THE YAKIMA VALLEY

    SciTech Connect

    Last, George V.; Bachmann, Matthew P.; Bjornstad, Bruce N.

    2011-05-05

    The climate and geology of eastern Washington are ideally suited to the production of hops and wine grapes. Nearly all of Washington’s hop and wine-grape production is located in the lower Yakima River Basin , which is one of the most intensively irrigated areas in the United States. Most of this irrigation water has been supplied by surface water reservoirs and canal systems drawing from the Yakima River. However, increasing demands for water has spurred the increased use of groundwater resources. This field trip guide explores many aspects of the geology and hydrogeology in the lower Yakima River Basin, particularly as they relate to water resources that support the local beer and wine industries.

  12. Hydrogeologic data from a test well at Kathryn Abbey Hanna Park, City of Jacksonville, Florida

    USGS Publications Warehouse

    Brown, D.P.; Johnson, R.A.; Baker, J.S.

    1984-01-01

    A 2,026-foot test well was drilled at Hanna Park, City of Jacksonville, Florida, to obtain hydrogeologic data. Drill cuttings and water samples were collected, and water-level measurements and lithologic and geophysical logs were made. The well is constructed with 6-inch diameter casing from land surface to a depth of 1,892 feet and cement grouted in place. The remainder is open hole. The uppermost 411 feet of material penetrated by the well consists of sand, clayey sand, phosphatic sandy clay, coquina, sandy limestone, and dolostone. In the remainder of the hole, the material consists of limestone and dolostone, which comprise the Floridan aquifer in the area. (USGS)

  13. Hydrogeology and soil gas at J-field, Aberdeen Proving Ground, Maryland. Water resources investigations

    SciTech Connect

    Hughes, W.B.

    1993-12-31

    Disposal of chemical warfare agents, munitions, and industrial chemicals in J-Field, Aberdeen Proving Ground, Maryland, has contaminated soil, ground water, and surface water. Seven exploratory borings and 38 observation wells were drilled to define the hydrogeologic framework at J-Field and to determine the type, extent, and movement of ground-water contaminants. Water in the surficial aquifer flows laterally from topographically high areas to discharge areas in marshes and streams, and vertically to the underlying confined aquifer. Analyses of soil-gas samples indicated high relative-flux values of chlorinated solvents, phthalates, and hydrocarbons at the toxic-materials disposal area, white-phosphorus disposal area, and riot-control-agent disposal area.

  14. An Analysis Platform for Multiscale Hydrogeologic Modeling with Emphasis on Hybrid Multiscale Methods

    SciTech Connect

    Scheibe, Timothy D.; Murphy, Ellyn M.; Chen, Xingyuan; Rice, Amy K.; Carroll, Kenneth C.; Palmer, Bruce J.; Tartakovsky, Alexandre M.; Battiato, Ilenia; Wood, Brian D.

    2015-01-01

    One of the most significant challenges facing hydrogeologic modelers is the disparity between those spatial and temporal scales at which fundamental flow, transport and reaction processes can best be understood and quantified (e.g., microscopic to pore scales, seconds to days) and those at which practical model predictions are needed (e.g., plume to aquifer scales, years to centuries). While the multiscale nature of hydrogeologic problems is widely recognized, technological limitations in computational and characterization restrict most practical modeling efforts to fairly coarse representations of heterogeneous properties and processes. For some modern problems, the necessary level of simplification is such that model parameters may lose physical meaning and model predictive ability is questionable for any conditions other than those to which the model was calibrated. Recently, there has been broad interest across a wide range of scientific and engineering disciplines in simulation approaches that more rigorously account for the multiscale nature of systems of interest. In this paper, we review a number of such approaches and propose a classification scheme for defining different types of multiscale simulation methods and those classes of problems to which they are most applicable. Our classification scheme is presented in terms of a flow chart (Multiscale Analysis Platform or MAP), and defines several different motifs of multiscale simulation. Within each motif, the member methods are reviewed and example applications are discussed. We focus attention on hybrid multiscale methods, in which two or more models with different physics described at fundamentally different scales are directly coupled within a single simulation. Very recently these methods have begun to be applied to groundwater flow and transport simulations, and we discuss these applications in the context of our classification scheme. As computational and characterization capabilities continue to improve, we envision that hybrid multiscale modeling will become more common and may become a viable alternative to conventional single-scale models in the near future.

  15. Geophysical framework of the southwestern Nevada volcanic field and hydrogeologic implications

    SciTech Connect

    Grauch, V.J.S.; Sawyer, D.A.; Fridrich, C.J.; Hudson, M.R.

    2000-06-08

    Gravity and magnetic data, when integrated with other geophysical, geological, and rock-property data, provide a regional framework to view the subsurface geology in the southwestern Nevada volcanic field. The authors have loosely divided the region into six domains based on structural style and overall geophysical character. For each domain, they review the subsurface tectonic and magmatic features that have been inferred or interpreted from previous geophysical work. Where possible, they note abrupt changes in geophysical fields as evidence for potential structural or lithologic control on ground-water flow. They use inferred lithology to suggest associated hydrogeologic units in the subsurface. The resulting framework provides a basis for investigators to develop hypotheses for regional ground-water pathways where no drill-hole information exists. The authors discuss subsurface features in the northwestern part of the Nevada Test Site and west of the Nevada Test Site in more detail to address potential controls on regional ground-water flow away from areas of underground nuclear-weapons testing at Pahute Mesa. Subsurface features of hydrogeologic importance in these areas are (1) the resurgent intrusion below Timber Mountain, (2) a NNE-trending fault system coinciding with western margins of the Silent Canyon and Timber Mountain caldera complexes, (3) a north-striking, buried fault east of Oasis Mountain extending for 15 km, which they call the Hogback fault, and (4) an east-striking transverse fault or accommodation zone that, in part, bounds Oasis Valley basin on the south, which they call the Hot Springs fault. In addition, there is no geophysical nor geologic evidence for a substantial change in subsurface physical properties within a corridor extending from the northwestern corner of the Rainier Mesa caldera to Oasis Valley basin (east of Oasis Valley discharge area). This observation supports the hypothesis of other investigators that regional ground water from Pahute Mesa is likely to follow a flow path that extends southwestward to Oasis Valley discharge area.

  16. Applications of ichnology to hydrogeology, with examples from the Cape Fear Formation (Cretaceous), South Carolina

    SciTech Connect

    Martin, A.J. . Geosciences Program); Simones, G.C. )

    1992-01-01

    Ichnology, the study of modern and ancient traces left by organisms, has provided supplemental information to geologic subdisciplines such as sedimentology and stratigraphy. The major objective of the authors paper is to emphasize the valuable information that can be conveyed by trace fossils in the investigation of hydrogeologic units. Bioturbation has a net effect of mixing different types and layers of sediments, such as introducing clays into sands and vice versa. This mixing can decrease porosity and permeability of sandy units, thus changing potential aquifers into confining units. For example, a sandy fluvial deposit will contain distinctive nonmarine trace fossils, thus defining channel sands that may serve as permeable conduits for ground-water flow. In contrast, a sandy shelf deposit will contain marine trace fossils in a sand body geometry that will be markedly different from aquifers produced in nonmarine environments. Bioturbation also causes geochemical and diagenetic changes in sediments, causing irrigation of previously anoxic sediments and precipitation of ion oxides. The Cretaceous Cape Fear Formation of the Atlantic Coastal Plain, in the subsurface of South Carolina, is presented as an example of a hydrogeologic unit that has been reinterpreted using ichnologic data. Extensive bioturbation caused mixing of clays and sands in Cape Fear sediments, which resulted in the Cape Fear becoming a regional confining system. Trace fossil assemblages indicate a brackish water environment, perhaps estuarine, for the Cape Fear, as opposed to previous interpretations of fluvial and deltaic environments. Bioturbated zones also have significantly more oxidized iron than unbioturbated zones, highlighting potential effects on ground-water quality.

  17. An innovative hydrogeologic setting for disposal of low-level radioactive wastes

    NASA Astrophysics Data System (ADS)

    Legrand, Harry E.

    1989-05-01

    A natural unique hydrogeological setting favorable for safe and economical disposal of low-level radioactive wastes occurs in the flat hinterland of southeastern North Carolina. The uniqueness results partly from the absence of vertical and horizontal groundwater gradients, representing a nonflow, or null, zone. The null setting is localized to key horizons 30 to 75 feet below land surface and to areas where glauconitic sandy clays of the Peedee Formation lie under less than 25 feet of surficial sandy clays; the Peedee contains nearly stagnant brackish groundwater slightly below the proposed disposal zone. Issues to overcome include: (1) demonstrating better combined safety and economical features over conventional and prescribed settings, (2) dewatering the low-permeability disposal zone for the 20-year operational period, and (3) changing rules to allow disposal slightly below the zone in which the normal water table occurs. Favorable site characteristics of the key setting are: (1) no major aquifer to contaminate, (2) no surface streams or lakes to contaminate, (3) optimal ion exchange and sorptive capacity (clay and glauconite pellets), (4) no appreciable or distinctive vertical and horizontal gradients, (5) no elongated contaminated plume to develop, (6) no surface erosion, (7) a capable setting for injection of potential contaminated water into deep brackish water wells, if needed and allowed, (8) minimum problems of the “overfilled bathtub effect,” (9) no apparent long-term harmful environmental impact (normal water table would be restored after the 20-year period), (10) relatively inexpensive disposal (engineered barriers not needed and desired), (11) simple and relatively inexpensive monitoring, (12) large tracts of land likely available, and (13) sparse population. In spite of legal and political obstacles to shallow land burial, the null setting described is a capable hydrogeological host to contain low-level radioactive wastes. The setting may have safety and economic advantages over selected sites in eastern North America and over innovative technological experiences in Europe.

  18. Bringing Together Co-located Geological, Geophysical and Hydrogeologic Observations of Cemented Fault-Zone Permeability

    NASA Astrophysics Data System (ADS)

    Wilson, J. L.; Spinelli, G. A.; Mozley, P.

    2014-12-01

    We examine co-located outcrop and subsurface geological, geophysical, and hydrogeological observations of a cemented fault in the Rio Grande rift. The partially cemented Loma Blanca fault offsets poorly consolidated piedmont slope and alluvial sediments; along parts of its exposure the fault consists of a 2- to 5-m-wide calcium carbonate cemented zone. The degree of cementation of the fault, which varies along its >4 km long surface exposure, is closely related to host-sediment grain size; coarser grained sections of the fault are more strongly cemented than finer grained portions. We hypothesize that the spatially variable degree and thickness of cementation is a key control on the ability of the Loma Blanca fault to act as a barrier to fault-normal fluid flow. We use geologically-validated geophysical observations to map variations in fault-zone parameters in the subsurface, collecting co-located GPR, DC-resistivity, and audio-magnetotellurics data along a transect across the fault. Differences in the electrical properties between strata offset by the fault allow us to constrain fault orientation and throw. Future investigations of the relationships between the degree of fault-zone cementation and normalized chargeability may allow us to map the estimated degree of cementation in the sub-surface. Using mathematical modeling we test alternative designs for future pumping and injection well tests that will be used to update estimates of the location, orientation, and properties of the fault, especially fault-normal permeability. The goal is a novel fault-zone permeability model based on the integration of geological, geophysical, and hydrogeological observations and models.

  19. Hydrogeology of the Croton-Ossining area, Westchester County, New York

    USGS Publications Warehouse

    Reynolds, Richard J.

    1988-01-01

    The hydrogeology of a 29-sq-mi area surrounding the village of Croton-on-Hudson, New York, is summarized on 6 sheets at 1:12 ,000 scale that show locations of wells and test holes, surficial geology, geologic sections, bedrock geology, land use, and soil permeability. The primary stratified-drift aquifer in this area is the Croton River aquifer, which consists of outwash sand and gravel that partly fills the Croton River valley from the New Croton Dam to the Hudson River--a distance of approximately 3 miles. The valley is narrow and ranges in width from 100 to 1,900 ft, and its v-notch bedrock floor ranges from 30 to 50 ft below sea level. Detailed hydrogeologic studies during 1936-38 showed the stratigraphy to consist of an upper water-table aquifer with a saturated thickness of about 35 ft, underlain by a silt and clay confining unit 8 to o0 ft in thickness that in turn is underlain by a lower confined outwash aquifer up to 40 ft thick. Aquifer-test data and laboratory permeability tests show that the average hydraulic conductivity of the upper outwash aquifer is 475 ft/d, and that of the lower confined aquifer is about 300 ft/d. The aquifer is recharged through direct precipitation, runoff from adjacent hillsides, and leakage under the new Croton Dam. Previous studies estimate the average leakage under the dam to be 0.65 Mgal/d and the total average daily recharge to the aquifer between New Croton Dam and Quaker Bridge to be 1.73 Mgal/d. (USGS)

  20. Hydrogeologic controls on induced seismicity in crystalline basement rocks due to fluid injection into basal reservoirs.

    PubMed

    Zhang, Yipeng; Person, Mark; Rupp, John; Ellett, Kevin; Celia, Michael A; Gable, Carl W; Bowen, Brenda; Evans, James; Bandilla, Karl; Mozley, Peter; Dewers, Thomas; Elliot, Thomas

    2013-01-01

    A series of Mb 3.8-5.5 induced seismic events in the midcontinent region, United States, resulted from injection of fluid either into a basal sedimentary reservoir with no underlying confining unit or directly into the underlying crystalline basement complex. The earthquakes probably occurred along faults that were likely critically stressed within the crystalline basement. These faults were located at a considerable distance (up to 10?km) from the injection wells and head increases at the hypocenters were likely relatively small (?70-150?m). We present a suite of simulations that use a simple hydrogeologic-geomechanical model to assess what hydrogeologic conditions promote or deter induced seismic events within the crystalline basement across the midcontinent. The presence of a confining unit beneath the injection reservoir horizon had the single largest effect in preventing induced seismicity within the underlying crystalline basement. For a crystalline basement having a permeability of 2?×?10(-17) ?m(2) and specific storage coefficient of 10(-7) /m, injection at a rate of 5455?m(3) /d into the basal aquifer with no underlying basal seal over 10?years resulted in probable brittle failure to depths of about 0.6?km below the injection reservoir. Including a permeable (kz ?=?10(-13) ?m(2) ) Precambrian normal fault, located 20?m from the injection well, increased the depth of the failure region below the reservoir to 3?km. For a large permeability contrast between a Precambrian thrust fault (10(-12) ?m(2) ) and the surrounding crystalline basement (10(-18) ?m(2) ), the failure region can extend laterally 10?km away from the injection well. PMID:23745958

  1. Hydrogeology of the Tully Lakes area in southern Onondaga and Cortland counties, New York

    USGS Publications Warehouse

    Kappel, William M.; Miller, Todd S.; Hetcher, Kari K.

    2001-01-01

    Glacial processes created the many kettlehole lakes, ponds, and depressions in the Tully Lakes area, as well as the Valley Heads Moraine, which forms the drainage divide between the St. Lawrence River drainage to the north and the Susquehanna River drainage to the south. The first hydrogeologic studies of the Tully Lakes area began in the 1870's, when the lakes were considered as a possible water supply for the city of Syracuse. Water was diverted from some of the northwestern lakes and ponds into the Tully Valley; these diversions occurred as early as the 1840's and ceased in the early 1960's, with the closure of the eastern Tully Valley brinefield. In 1998, the USGS began a 2-year hydrogeologic study of the aquifer system underlying the Tully Lakes area that included monitoring water levels in five of the Tully Lakes and more than 50 wells. The average annual water-level fluctuations in the three western lakes ranged from about 2.5 feet to 6 feet. Water-level fluctuations in the eastern lakes, near the center of the valley, were much less--about 1.5 feet, because these lakes have natural outlets. Three sets of ground-water-level measurements were made from the spring recharge period through the fall dry period of 2000. The resulting potentiometric-surface maps indicate that the water-level declines from the spring to the fall ranged from 1.5 to 8 feet. The ground-water divide is about 1 mile south of the Valley Heads Moraine crest in the spring and migrates southward in response to declining water levels in the surficial aquifer during the fall. Water-surface altitudes in the kettlehole lakes and ponds respond slowly to seasonal water-level changes in the surrounding aquifer and often differ from water levels in the aquifer because the poorly permeable lakebed sediments impede the exchange of water.

  2. Modelling hyporheic processes for regulated rivers under transient hydrological and hydrogeological conditions

    NASA Astrophysics Data System (ADS)

    Siergieiev, D.; Ehlert, L.; Reimann, T.; Lundberg, A.; Liedl, R.

    2015-01-01

    Understanding the effects of major hydrogeological controls on hyporheic exchange and bank storage is essential for river water management, groundwater abstraction, restoration and ecosystem sustainability. Analytical models cannot adequately represent complex settings with, for example, transient boundary conditions, varying geometry of surface water-groundwater interface, unsaturated and overland flow, etc. To understand the influence of parameters such as (1) sloping river banks, (2) varying hydraulic conductivity of the riverbed and (3) different river discharge wave scenarios on hyporheic exchange characteristics such as (a) bank storage, (b) return flows and (c) residence time, a 2-D hydrogeological conceptual model and, subsequently, an adequate numerical model were developed. The numerical model was calibrated against observations in the aquifer adjacent to the hydropower-regulated Lule River, northern Sweden, which has predominantly diurnal discharge fluctuations during summer and long-lasting discharge peaks during autumn and winter. Modelling results revealed that bank storage increased with river wave amplitude, wave duration and smaller slope of the river bank, while maximum exchange flux decreased with wave duration. When a homogeneous clogging layer covered the entire river-aquifer interface, hydraulic conductivity positively affected bank storage. The presence of a clogging layer with hydraulic conductivity < 0.001 m d-1 significantly reduced the exchange flows and virtually eliminated bank storage. The bank storage return/fill time ratio was positively related to wave amplitude and the hydraulic conductivity of the interface and negatively to wave duration and bank slope. Discharge oscillations with short duration and small amplitude decreased bank storage and, therefore, the hyporheic exchange, which has implications for solute fluxes, redox conditions and the potential of riverbeds as fish-spawning locations. Based on these results, river regulation strategies can be improved by considering the effect of certain wave event configurations on hyporheic exchange to ensure harmonious hydrogeochemical functioning of the river-aquifer interfaces and related ecosystems.

  3. An analysis platform for multiscale hydrogeologic modeling with emphasis on hybrid multiscale methods.

    PubMed

    Scheibe, Timothy D; Murphy, Ellyn M; Chen, Xingyuan; Rice, Amy K; Carroll, Kenneth C; Palmer, Bruce J; Tartakovsky, Alexandre M; Battiato, Ilenia; Wood, Brian D

    2015-01-01

    One of the most significant challenges faced by hydrogeologic modelers is the disparity between the spatial and temporal scales at which fundamental flow, transport, and reaction processes can best be understood and quantified (e.g., microscopic to pore scales and seconds to days) and at which practical model predictions are needed (e.g., plume to aquifer scales and years to centuries). While the multiscale nature of hydrogeologic problems is widely recognized, technological limitations in computation and characterization restrict most practical modeling efforts to fairly coarse representations of heterogeneous properties and processes. For some modern problems, the necessary level of simplification is such that model parameters may lose physical meaning and model predictive ability is questionable for any conditions other than those to which the model was calibrated. Recently, there has been broad interest across a wide range of scientific and engineering disciplines in simulation approaches that more rigorously account for the multiscale nature of systems of interest. In this article, we review a number of such approaches and propose a classification scheme for defining different types of multiscale simulation methods and those classes of problems to which they are most applicable. Our classification scheme is presented in terms of a flowchart (Multiscale Analysis Platform), and defines several different motifs of multiscale simulation. Within each motif, the member methods are reviewed and example applications are discussed. We focus attention on hybrid multiscale methods, in which two or more models with different physics described at fundamentally different scales are directly coupled within a single simulation. Very recently these methods have begun to be applied to groundwater flow and transport simulations, and we discuss these applications in the context of our classification scheme. As computational and characterization capabilities continue to improve, we envision that hybrid multiscale modeling will become more common and also a viable alternative to conventional single-scale models in the near future. PMID:24628122

  4. UNDERSTANDING HARD ROCK HYDROGEOLOGY THROUGH AN EXPERIMENTAL HYDROGEOLOGICAL PARK IN SOUTH INDIA: Site development and investigations on the major role of the fractured zone in crystalline aquifers

    NASA Astrophysics Data System (ADS)

    Ahmed, S.; Guiheneuf, N.; Boisson, A.; Marechal, J.; Chandra, S.; Dewandel, B.; Perrin, J.

    2012-12-01

    In water stressed south India most of the groundwater used for irrigation is pumped from crystalline rocks aquifers. In those structures groundwater flow dominantly occur in a shallow higher-permeability zone that overlies a deeper lower-permeability zone hosting little flow. The fractured zone of the weathering profile plays an important role for groundwater. In order to understand clearly this impact on water availability and quality changes the Experimental Hydrogeological Park at Choutuppal, Andhra Pradesh, India is developed in the framework of the SORE H+ network. Several hydraulic tests (injection, flowmeter profiles, single-packer tests…) and geophysical measurements (ERT, Borehole logging…) are carried out on the site in order to characterize the depth-dependence of hydrodynamic parameters in the Indian Archean granite. Specific investigation on a borewell through packer tests demonstrate that the most conductive part of the aquifer corresponds to the upper part of the fractured layer, located just below the saprolite bottom, between 15 meters and 20 meters depth. There is no highly conductive fracture beyond 20 meters depth and no indication for any conductive fracture beyond 25 meters depth. Packer tests show that the upper part of the fractured layer (15-20 m depth) is characterized by a good vertical connectivity. On the contrary, the tests carried out below 20 m depth show no vertical connectivity at all. The geometry of the fracture network and associated hydrodynamic parameters are in agreement with the conceptual model of hard-rock aquifers that derive its properties from weathering processes. The general existence of such a highly conductive structure at the top of the fractured zone has a great impact on water prospection and exploitation in such crystalline aquifers.

  5. Hydrogeologic data related to the potential for stock-water development on federally owned rangeland near Dillon, Montana

    USGS Publications Warehouse

    Levings, J.F.

    1985-01-01

    Existing hydrogeologic data and information were synthesized for 20 sites on federally owned rangeland near Dillon, Montana. The purpose was to assist the U.S. Bureau of Land Management in evaluating the potential for developing additional stock-water supplies. Hydrologic and geologic conditions at most of the sites were verified by onsite inspection during the summer of 1984. Each site is described in terms of location, altitude of land surface, inferred aquifer(s), estimated depth to water, estimated drilling depth, estimated yield, estimated dissolved-solids concentration, hydrogeologic setting, and development. A plate shows the location of wells and springs, dissolved-solids concentrations and chemical-constituent diagrams for water samples, ownership status for selected rangeland areas near Dillon. (USGS)

  6. Calendar Year 1994 Groundwater Quality Report for the Bear Creek Hydrogeologic Regime Y-12 Plant, Oak Ridge, Tennessee

    SciTech Connect

    1995-02-01

    This annual groundwater quality report (GWQR) contains groundwater and surface water quality data obtained during the 1994 calendar year (CY) at several hazardous and non-hazardous waste-management facilities associated with the U.S. Department of Energy (DOE) 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 (directions in this report are in reference to the Y-12 administrative grid system) within the Bear Creek Hydrogeologic Regime (Bear Creek Regime), one of three hydrogeologic regimes defined for the purposes of groundwater and surface water quality monitoring at the Y-12 Plant. The Environmental Management Department of the Y-12 Plant Health, Safety, Environment, and Accountability (HSEA) Organization manages the groundwater monitoring activities in the Bear Creek Regime 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 provide for protection of groundwater resources consistent with federal, state, and local requirements and in accordance with DOE Orders and Martin Marietta Energy Systems, Inc. (Energy Systems) corporate policy. The annual GWQR for the Bear Creek Regime is completed in two parts. 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.

  7. Review and reconnaissance of the hydrogeology of Tertiary sedimentary rocks in the vicinity of Frenchman Flat, Nevada Test Site

    SciTech Connect

    Prothro, L.B.; Drellack, S.L. Jr.

    1997-09-01

    Work is currently underway within the Underground Test Area (UGTA) subproject of the US Department of Energy/Nevada Operations Office Environmental Restoration Program to develop corrective action plans in support of the overall corrective action strategy for the Nevada Test Site (NTS) as established in the Federal Facility Agreement and Consent Order (FFACO, 1996). A closure plan is currently being developed for Frenchman Flat, which has been identified in the FFACO as a Corrective Action Unit (CAU). Part of this effort requires that hydrogeologic data be compiled for inclusion in a CAU-specific hydrologic flow and transport model that will be used to predict contaminant boundaries. Hydrogeologic maps and cross sections are currently being prepared for use in the model to define the nature and extent of aquifers and confining units that might influence the flow of contaminated groundwater from underground nuclear tests conducted in Frenchman Flat. During this effort, it has been found that older Tertiary-age sediments might be hydrogeologically important in the Frenchman Flat model area. Although the character and extent of these units are poorly known, there is reason to believe that in some parts of Frenchman Flat they may lie between the regional Lower Carbonate Aquifer (LCA) and the younger Tertiary saturated alluvium and volcanic units in which several underground nuclear tests were conducted. It was not possible to quickly determine their extent, or ascertain whether or not these units might act as confining units or aquifers. The work described in this report was done to gain a better understanding of the hydrogeology of these rocks.

  8. Hydrogeology and extent of saltwater intrusion on Manhasset Neck, Nassau County, New York

    USGS Publications Warehouse

    Stumm, Frederick; Lange, A.D.; Candela, J.L.

    2002-01-01

    Manhasset Neck, a peninsula on the northern shore of Long Island, N.Y., is underlain by unconsolidated deposits that form a sequence of aquifers and confning units. Ground water at several public-supply wells has been affected by the intrusion of saltwater from the surrounding embayments (Manhasset Bay, Long Island Sound, Hempstead Harbor). Twenty-two boreholes were drilled during 1992-96 for the collection of hydrogeologic, geochemical, and geophysical data to delineate the subsurface geology and the extent of saltwater intrusion within the peninsula. A series of continuous high-resolution seismic- reflection surveys was completed in 1993 and 1994 to delineate the character and extent of the hydrogeologic deposits beneath the embayments surrounding Manhasset Neck. The new drill-core data indicate two hydrogeologic units--the North Shore aquifer and the North Shore confining unit--where the Lloyd aquifer, Raritan confining unit, and the Magothy aquifer have been completely removed by glacial erosion. Water levels at selected observation wells were measured quarterly throughout the study. These data, and continuous water-level records, indicate that (1) the upper glacial (water-table) and Magothy aquifers are hydraulically connected and that their water levels do not respond to tidal fluctuations, and (2) the Lloyd and North Shore aquifers also are hydraulically connected, but their water levels do respond to pumping and tidal fluctuations. Offshore seismic-reflection surveys in the surrounding embayments, and drill-core samples, indicate at least four glacially eroded buried valleys with subhorizontal, parallel reflectors indicative of draped bedding that is interpreted as infilling by silt and clay. The buried valleys (1) truncate the surrounding coarse-grained deposits, (2) are asymmetrical and steep sided, (3) trend northwest-southeast, (4) are 2 to 4 miles long and about 1 mile wide, and (5) extend to more than 400 feet below sea level. Water from 12 public-supply wells screened in the Magothy and upper glacial aquifers contained volatile organic compounds in concentrations above the New York State Department of Health Drinking Water maximum contaminant levels, as did water from one public- supply well screened in the Lloyd aquifer and from two observation wells screened in the upper glacial aquifer. Five distinct areas of saltwater intrusion have been delineated in Manhasset Neck; three extend into the Lloyd and North Shore aquifers, and two extend into the upper glacial and Magothy aquifers. Borehole-geophysical-logging data indicate that several of these saltwater wedges range from a few feet to more than 125 feet in thickness and have sharp freshwater-saltwater interfaces, and that chloride concentrations within these wedges in 1997 ranged from 102 to 9,750 milligrams per liter. Several public-supply wells have either been shut down or are currently being affected by these saltwater wedges. Data show active saltwater intrusion in at least two of the wedges.

  9. Hydrogeologic Setting and Ground-Water Flow in the Leetown Area, West Virginia

    USGS Publications Warehouse

    Kozar, Mark D.; Weary, David J.; Paybins, Katherine S.; Pierce, Herbert A.

    2007-01-01

    The Leetown Science Center is a research facility operated by the U.S. Geological Survey that occupies approximately 455-acres near Kearneysville, Jefferson County, West Virginia. Aquatic and fish research conducted at the Center requires adequate supplies of high-quality, cold ground water. Three large springs and three production wells currently (in 2006) supply water to the Center. The recent construction of a second research facility (National Center for Cool and Cold Water Aquaculture) operated by the U.S. Department of Agriculture and co-located on Center property has placed additional demands on available water resources in the area. A three-dimensional steady-state finite-difference ground-water flow model was developed to simulate ground-water flow in the Leetown area and was used to assess the availability of ground water to sustain current and anticipated future demands. The model also was developed to test a conceptual model of ground-water flow in the complex karst aquifer system in the Leetown area. Due to the complexity of the karst aquifer system, a multidisciplinary research study was required to define the hydrogeologic setting. Geologic mapping, surface- and borehole-geophysical surveys, stream base-flow surveys, and aquifer tests were conducted to provide the hydrogeologic data necessary to develop and calibrate the model. It would not have been possible to develop a numerical model of the study area without the intensive data collection and methods developments components of the larger, more comprehensive hydrogeologic investigation. Results of geologic mapping and surface-geophysical surveys verified the presence of several prominent thrust faults and identified additional faults and other complex geologic structures (including overturned anticlines and synclines) in the area. These geologic structures are known to control ground-water flow in the region. Results of this study indicate that cross-strike faults and fracture zones are major avenues of ground-water flow. Prior to this investigation, the conceptual model of ground-water flow for the region focused primarily on bedding planes and strike-parallel faults and joints as controls on ground-water flow but did not recognize the importance of cross-strike faults and fracture zones that allow ground water to flow downgradient across or through less permeable geologic formations. Results of the ground-water flow simulation indicate that current operations at the Center do not substantially affect either streamflow (less than a 5-percent reduction in annual streamflow) or ground-water levels in the Leetown area under normal climatic conditions but potentially could have greater effects on streamflow during long-term drought (reduction in streamflow of approximately 14 percent). On the basis of simulation results, ground-water withdrawals based on the anticipated need for an additional 150 to 200 gal/min (gallons per minute) of water at the Center also would not seriously affect streamflow (less than 8 to 9 percent reduction in streamflow) or ground-water levels in the area during normal climatic conditions. During drought conditions, however, the effects of current ground-water withdrawals and anticipated additional withdrawals of 150 to 200 gal/min to augment existing supplies result in moderate to substantial declines in water levels of 0.5-1.2 feet (ft) in the vicinity of the Center's springs and production wells. Streamflow was predicted to be reduced locally by approximately 21 percent. Such withdrawals during a drought or prolonged period of below normal ground-water levels would result in substantial declines in the flow of the Center's springs and likely would not be sustainable for more than a few months. The drought simulated in this model was roughly equivalent to the more than 1-year drought that affected the region from November 1998 through February 2000. The potential reduction in streamflow is a result of capture of ground water tha

  10. Hydrogeology characterization of roto-translational slides in flysch rock masses

    NASA Astrophysics Data System (ADS)

    Ronchetti, F.; Borgatti, L.; Cervi, F.; Corsini, A.; Piccinini, L.; Vincenzi, V.; Truffelli, G.

    2009-04-01

    The hydrogeological characteristics of roto-traslational slides in flysch are complex, due to the inherent anisotropy and heterogeneity of such rock masses. The paper deals with the hydrogeological characterization of a reactivated roto-translational slide affecting Cretaceous flysch, located in the Northern Apennines of Italy. In situ permeability and pumping test, continuous monitoring of groundwater levels, hydrochemical and isotope analyses, and finally uranine tracers were the adopted prospecting methods. The landslide sector classified as rock slide extends for about 0.5 km2 and is characterized by a marked active sliding surface at 40 m depth. Borehole cores showed an upper 10-20 m landslide layer made of clayey debris, and a lower 20 m landslide layer made of highly fractured sandstone-rich flysch. Below sliding surface the flysch is much less fractured and it is overlying a clayey mélange. The hydraulic conductivity of both layers of the rock slide body was estimated with more than ten borehole permeability tests and by 5 slug-tests in open-pipe piezometers. Results highlighted a variability of permeability at different depths and locations, between 10-6 to 10-8 m/s, linked to fracturing of rock masses and to clay fraction. Groundwater levels were monitored for more than 3 years by means of transducers in 5 standpipe piezometers, fissured above or below the sliding surface. Results showed that two overlaying aquifers exist at the slope scale: an unconfined one, in the fractured flysch of the rock slide; a confined one, in the undisturbed flysch below sliding surface. Pore pressure in the unconfined aquifer is controlled by rainfall, with fluctuation of several meters occurring hours or days from onset of precipitation. On the contrary, pore pressure in the confined aquifer shows little response to precipitation events, has fluctuations of few meters related to seasonal trends, and maintains pressure head higher than that in the unconfined one. This makes it a relevant factor for the stability of the slide. Storage coefficient of 10-3 and Trasmissivity of 1E-5 m2/s were estimated for the unconfined aquifer with a pumping test carried out with several control piezometers. The geochemical characterization obtained by sampling and lab analysis highlighted two groundwater types in the landslide area. One shallow, directly connected with rainfall, that can be classified as cold (13° C) and Ca-carbonate, rich with low electric conductivity (800 ?S/cm). The second consists of deep-fluids, rich in Na-sulfate, characterized by the mixing between the two extreme hydrotypes Na-bicarbonate waters and Ca-sulfate waters. This deep-fluids are characterized by cold temperature (13° C) and high salinity, over 4000 ?S/cm. The tracer test between the undisturbed rock mass in the crown zone and the 12 control points in the landslide body (at different depths) indicates that there is no connection between the two parts. Even assuming the failing of the test for high dilution/dispersion, considering the high quantity of uranine injected and its conservative behavior in such flysch rocks, it can be reasonably argued that there's no significant groundwater exchange between the two domains. The results obtained in Ca' Lita show a high complexity of the groundwater flow due to high heterogeneity and anisotropy of the hydraulic characteristics inside the deposits of the rock slide and in the underlying fractured bedrock. Moreover, the hydrogeological study has individuated a rising of deep fluids in the landslide area, which can have a negative effect on the stability of the whole slope. The research results will be the basis of numerical groundwater flow models of the slope and will be also used to design and implement deep drainage systems for risk mitigation purposes.

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

    SciTech Connect

    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.

  12. Application of ground-penetrating radar methods in determining hydrogeologic conditions in a karst area, west-central Florida

    USGS Publications Warehouse

    Barr, G.L.

    1993-01-01

    Ground-penetrating radar (GPR) is useful as a surface geophysical method for exploring geology and subsurface features in karst settings. Interpretation of GPR data was used to infer lithology and hydrogeologic conditions in west-central Florida. This study demonstrates how GPR methods can be used to investigate the hydrogeology of an area. GPR transmits radio- frequency electromagnetic waves into the ground and receives reflected energy waves from subsurface interfaces. Subsurface profiles showing sediment thickness, depth to water table and clay beds, karst development, buried objects, and lake-bottom structure were produced from GPR traverses obtained during December 1987 and March 1990 in Pinellas, Hillsborough, and Hardee Counties in west-central Florida. Performance of the GPR method is site specific, and data collected are principally affected by the sediment and pore fluids, conductances and dielectric constants. Effective exploration depths of the GPR surveys through predominately unsaturated and saturated sand and clay sediments at five study sites ranged from a few feet to greater than 50 feet below land surface. Exploration depths were limited when high conductivity clay was encountered, whereas greater exploration depths were possible in material composed of sand. Application of GPR is useful in profiling subsurface conditions, but proper interpretation depends upon the user's knowledge of the equipment and the local hydrogeological setting, as well as the ability to interpret the graphic profile.

  13. Zone Management of Multi-Purpose Use of Groundwater Via Spatial Variability Analysis of Water Quality and Hydrogeology

    NASA Astrophysics Data System (ADS)

    Liang, C. P.; Chen, C. F.; Jang, C. S.; Chen, J. S.

    2014-12-01

    Groundwater is comprehensively used for irrigation, aquaculture and public water supply in Pingtung plain. Establishing a sound management plan of multi-purpose groundwater utilization in Pingtung plain is imperial for water resources sustainability. When extracting groundwater for such multi-purpose use, the major concerns are to assure the meets for the different water quality standards for various water use sectors demand and minimizing the pumping impacts on aquifers. The groundwater quality and hydrogeological conditions play important roles in multi-purpose groundwater utilization. Management and effective use of groundwater typically face great challenges, due to the spatial variability of groundwater quality and hydrogeological condition. This study combines the variability of groundwater quality and hydrological condition to propose zonal management of multi-purpose use of groundwater in Pingtung plain. Based on the water quality standards for various groundwater utilization sectors, the integration of hydrochemical parameters are used to delineate most appropriate zones of various groundwater utilization sectors. For evaluation of hydrogeological condition, transmissivity which represents the ability of water transmitted in aquifer is adopted to determine the most suitable zones of groundwater extraction. Based on the analytical results of the water quality parameters and transmissivity in combination with actual groundwater utilization, a zonal management plan of multi-purpose groundwater utilization is established. The framework in this project can provide an effective tool for government administrator establishing a zonal management of multi-purpose groundwater utilization in Pingtung plain.

  14. Hydrogeologic factors in the selection of shallow land burial sites for the disposal of low-level radioactive waste

    USGS Publications Warehouse

    Fischer, John N.

    1986-01-01

    In the United States, low-level radioactive waste is disposed of by shallow land burial. Commercial low-level radioactive waste has been buried at six sites, and low-level radioactive waste generated by the Federal Government has been buried at nine major and several minor sites. Several existing low-level radioactive waste sites have not provided expected protection of the environment. These shortcomings are related, at least in part, to an inadequate understanding of site hydrogeology at the time the sites were selected. To better understand the natural systems and the effect of hydrogeologic factors on long-term site performance, the U.S. Geological Survey has conducted investigations at five of the six commercial low-level radioactive waste sites and at three Federal sites. These studies, combined with those of other Federal and State agencies, have identified and confirmed important hydrogeologic factors in the effective disposal of low-level radioactive waste by shallow land burial. These factors include precipitation, surface drainage, topography, site stability, geology, thickness of the host soil-rock horizon, soil and sediment permeability, soil and water chemistry, and depth to the water table.

  15. Canadian groundwater inventory: Regional hydrogeological characterization of the south-central part of the maritimes basin

    USGS Publications Warehouse

    Rivard, C.; Michaud, Y.; Deblonde, C.; Boisvert, V.; Carrier, C.; Morin, R.H.; Calvert, T.; Vigneault, H.; Conohan, D.; Castonguay, S.; Lefebvre, R.; Rivera, A.; Parent, M.

    2008-01-01

    The Maritimes Groundwater Initiative (MGWI) is a large, integrated, regional hydrogeological study focusing on a representative area of the Maritimes Basin in eastern Canada. The study area covers a land surface of 10 500 km2, of which 9 400 km2 are underlain by sedimentary rocks. This sedimentary bedrock is composed of a sequence of discontinuous strata of highly variable hydraulic properties, and is generally overlain by a thin layer of glacial till(mostly 4-8 m thick, but can reach 20 m). Depending on the area, 46 to 100% of the population relieson groundwater for water supply, either from municipal wells or from private residential wells. The main objectives of this project were to improve the general understanding of groundwater-flow dynamics and to provide baseline information and tools for a regional groundwater-resource assessment. This bulletin presents the current state of understanding of this hydrogeological system, along with the methodology used to characterize and analyze its distinct behaviour at three different scales. This regional bedrock aquifer system contains confined and unconfined zones, and each of its lenticular permeable strata extends only a few kilometres. Preferential groundwater recharge occurs where sandy till is present. The mean annual recharge rate to the bedrock is estimated to range between 130 and 165 mm/a. Several geological formations of this basin provide good aquifers, with hydraulic conductivity in the range 5x10-6 to 10-4m/s. Based on results of numerical flow modelling, faults were interpreted to have a key role in the regional flow. Pumping-test results revealed that the fractured aquifers can locally be very heterogeneous and anisotropic, but behave similarly to porous media. Work performed at the local scale indicated that most water-producing fractures seem to be subhorizontal and generally oriented in a northeasterly direction, in agreement with regional structures and pumping-test results. Almost all residential wells are shallow (about 20 m) open holes that are cased only through the surficial sediments.

  16. Hydrogeologic Controls on the Deep Terrestrial Biosphere - Chemolithotrophic Energy for Subsurface Life on Earth and Mars

    NASA Astrophysics Data System (ADS)

    Sherwood Lollar, B.; Moran, J.; Tille, S.; Voglesonger, K.; Lacrampe-Couloume, G.; Onstott, T.; Pratt, L.; Slater, G.

    2009-05-01

    As exploration for gold, diamonds and base metals expand mine workings to depths of almost 3 km below the Earth's surface, the mines of the Canadian Shield provide a window into the deep biosphere as diverse, but to date less well-explored than the South African Gold Mines. To date investigations of the deep biosphere have, in most cases, focused on the marine subsurface, including deep sea sediments, hydrothermal vents, off-axis spreading centers and cold seeps. Yet the deep terrestrial subsurface hosted in the fracture waters of Archean Shield rocks provides an important analog and counterpoint to studies of the deep marine biosphere. Depending on the particular geologic and hydrogeologic setting, sites vary from those dominated by paleometeoric waters and microbial hydrocarbon production, to those in which H2 and hydrocarbon gases have been suggested to be a function of long-term accumulation of the products of water-rock interaction in the deepest, most saline fracture waters with residence times on the order of tens of millions of years. The hydrogeologically isolated fracture-controlled ground water system periodically generates steep redox gradients and chemical disequilibrium due to fracture opening, and episodic release of mM levels of H2 that support a redox driven microbial community of H2-utilizing sulfate reducers and methanogens. Exploration of these systems may provide information about the limits of the deep terrestrial biosphere, controls on the distribution of deep subsurface life, and the diversity of geochemical reactions that produce substrates on which microbiological communities at great depths survive. The geologically stable Precambrian cratons of Earth are arguably the closest analogs available to single-plate planets such as Mars. Studies of these Earth analogs imply that the habitability of the Martian crust might similarly not be restricted to sites of localized hydrothermal activity. While the presence of the Martian cryosphere and potential clathrates will affect the porosity and permeability, and net flux of gases from the Martian crust, the underlying principles of fracture-controlled energy sequestration and episodic release remain. Furthermore understanding the origin and distribution of biogenic and geologic sources of CH4 at these analog Earth sites will inform models and strategies for deciphering the origin of CH4 recently reported in the Martian atmosphere.

  17. Hydrogeologic controls on baseflow temperature distributions: Implications for stream temperature response to climate variability

    NASA Astrophysics Data System (ADS)

    Boutt, D. F.; Smith, Z.

    2012-12-01

    Ground water temperature distributions in the near surface are not uniform and are the complex result of a variety of near- and sub-surface processes. Heat from the atmosphere is input into the ground via conduction at the ground surface and advection of infiltrating water. These processes produce predictable distributions of temperature that have been used to investigate current and past climatic conditions, determine ground water velocities, and assess basin-scale heat transport in sedimentary systems. The purpose of this investigation is to test a hypothesis that timing and nature of ground water recharge (advection of heat into the subsurface) is a significant control on the temporal and spatial distribution of heat in the shallow subsurface. The advective movement of heat imposes a dominant control on the 3-dimensional subsurface temperature distribution and strongly affects stream baseflow temperatures. We present observational data supporting a strong hydrogeologic control on subsurface water temperatures. These temperature distributions are modified by advection and are significantly different than theoretical distributions in a conduction-dominated environment. The temperature distributions with depth and space are controlled by the aquifers internal hydrogeologic structure and connections to recharge areas. Synthetic modeling is used to address the following questions: (1) how quickly do ground water temperatures respond to a changing climate, and how quickly do they reach a new equilibrium following perturbation; (2) what is the role of recharge water temperature and timing on subsurface temperature distributions; and (3) how do these factors influence baseflow temperatures in stream systems of varying size. Two-dimensional numerical models are developed using Comsol Multiphysics to perform a sensitivity analysis of basin-scale temperature response and coupling to surface water. In nested ground water flow systems, discharge areas farther down the regional hydraulic gradient receive groundwater from increasingly longer flow paths. As such, temperatures in upper portions of the flow system respond sooner to temperature changes than those in lower portions of the system. The upper portions of the model achieved equilibrium with temperature forcing within a few years, while downstream portions required more than 10 years to achieve equilibrium. The results reiterate the importance of advection-driven heat flow to the thermal response of shallow ground water systems and nested basins. Seasonal temperature signatures penetrate deeper and farther down the regional gradient in highly advective systems versus moderately advective systems. Models illustrate the persistence of the seasonal increased heat signature in the subsurface and propagation of that signature with the regional gradient. Upstream discharge locations respond quickly to increased temperatures and receive higher temperature baseflow than under the baseline conditions. Downstream discharge locations are somewhat buffered from increased temperatures due to longer flow paths.

  18. Hydrogeologic inferences from geophysical and geologic investigation of the Standard Mine site, Elk Basin, Colorado

    NASA Astrophysics Data System (ADS)

    Minsley, B. J.; Caine, J. S.; Ball, L. B.; Burton, B.; Curry-Elrod, E.; Manning, A. H.; Verplanck, P. L.

    2009-12-01

    Geophysical and geologic data were collected at the Standard Mine in Elk Basin near Crested Butte, CO, to improve our understanding of the hydrogeologic controls in the basin and how they influence surface and groundwater interactions with nearby mine workings. The Tertiary Ohio Creek and Wasatch formations are the bedrock geologic units; both are primarily sandstones, but with differences in weathering and fracturing. Dikes, near-vertical normal faults, and polymetallic quartz veins with varying degrees of lateral continuity cut the sedimentary units. The net impact of these features, along with basin topography, makes it difficult to predict the behavior of the surface and groundwater systems. This integrated study utilizes geologic observations to help constrain subsurface information obtained from the analysis of surface geophysical measurements. This is a critical step toward using the geophysical data in a meaningful hydrogeologic framework. The approach combines the benefit of direct, but sparse, field observations with spatially continuous, but indirect, measurements of physical properties through the use of geophysics. Surface geophysical data includes electrical resistivity profiles aimed at imaging variability in subsurface structural properties and fluid content; self-potentials, which are sensitive to mineralized zones at this site and, to a lesser extent, shallow flow patterns; and magnetic measurements, which provide information on lateral variability in near-surface geologic features, although the minerals at this site are not strongly magnetized. Downhole caliper and optical televiewer logs were acquired in one well and provide valuable information on fracture properties. Field geologic observations include hand sample mineralogy and detailed mapping and characterization of faults, joints, and veins. Analyses of representative rock samples include magnetic susceptibility, mercury injection capillary pressure, semi-quantitative x-ray diffraction, mass spectroscopy elemental chemistry, and petrography. Preliminary results from all analyses are remarkably consistent with one another and suggest a heterogeneously distributed, fracture-dominated groundwater flow system. Resistivity models show a well-defined, highly resistive near-surface layer, likely representing the unsaturated zone. Selective leaching of pyrite combined with fracturing in the Ohio Creek formation may be responsible for localized areas of lower resistivity where surface waters intersect these features and result in increased saturation. Steeply dipping resistive features are spatially coincident with the observed major faults and veins, and are also evident in the self-potential data. Resistivity data, outcrop observations, petrography, and mercury injection permeability and porosity data are consistent with the Wasatch formation having significantly lower porosity and permeability than the Ohio Creek formation and associated fault rocks. This suggests that the physical juxtaposition of the two contrasting units may be a critical factor in controlling the distribution of surface water infiltration and groundwater-related acid rock drainage.

  19. The study of past damaging hydrogeological events for damage susceptibility zonation

    NASA Astrophysics Data System (ADS)

    Petrucci, O.; Pasqua, A. A.

    2008-08-01

    Damaging Hydrogeological Events are defined as periods during which phenomena, such as landslides, floods and secondary floods, cause damage to people and the environment. A Damaging Hydrogeological Event which heavily damaged Calabria (Southern Italy) between December 1972, and January 1973, has been used to test a procedure to be utilised in the zonation of a province according to damage susceptibility during DHEs. In particular, we analyzed the province of Catanzaro (2391 km2), an administrative district composed of 80 municipalities, with about 370 000 inhabitants. Damage, defined in relation to the reimbursement requests sent to the Department of Public Works, has been quantified using a procedure based on a Local Damage Index. The latter, representing classified losses, has been obtained by multiplying the value of the damaged element and the percentage of damage affecting it. Rainfall has been described by the Maximum Return Period of cumulative rainfall, for both short (1, 3, 5, 7, 10 consecutive days) and long duration (30, 60, 90, 180 consecutive days), recorded during the event. Damage index and population density, presumed to represent the location of vulnerable elements, have been referred to Thiessen polygons associated to rain gauges working at the time of the event. The procedure allowed us to carry out a preliminary classification of the polygons composing the province according to their susceptibility to damage during DHEs. In high susceptibility polygons, severe damage occurs during rainfall characterised by low return periods; in medium susceptibility polygons maximum return period rainfall and induced damage show equal levels of exceptionality; in low susceptibility polygons, high return period rainfall induces a low level of damage. The east and west sectors of the province show the highest susceptibility, while polygons of the N-NE sector show the lowest susceptibility levels, on account of both the low population density and high average rainfall characterizing these mountainous areas. The future analysis of further DHEs, using the tested procedure, can strengthen the obtained zonation. Afterwards, the results can prove useful in establishing civil defence plans, emergency management, and prioritizing hazard mitigation measures.

  20. Evaluation of geochemical and hydrogeological processes by geochemical modeling in an area affected by evaporite karstification

    NASA Astrophysics Data System (ADS)

    Acero, P.; Auqué, L. F.; Galve, J. P.; Gutiérrez, F.; Carbonel, D.; Gimeno, M. J.; Yechieli, Y.; Asta, M. P.; Gómez, J. B.

    2015-10-01

    The Ebro Valley in the outskirts of Zaragoza (NE Spain) is severely affected by evaporite karstification, leading to multiple problems related to subsidence and sinkhole formation. In this work, a combination of inverse (mixing + mass-balance) and forward (reaction-path) geochemical calculations is applied for the quantification of the main karstification processes and seasonal variations in this area. The obtained results prove the suitability of the applied methodology for the characterization of similar problems in other areas with scarce geological and hydrogeological information. The hydrogeology and hydrochemistry of the system can be mainly attributed to the mixing of variable proportions of concentrated groundwater from the evaporitic aquifer and more dilute water from the overlying alluvial aquifer. The existence of a good connection between these aquifers is supported by: (1) the fast changes in the hydrochemistry of the karst aquifer related to recharge by irrigation, and (2) the deduced input of evaporitic groundwater in the alluvial materials. The evolution in some parts of the alluvial/evaporitic aquifer system is clearly dominated by the seasonal variations in the recharge by dilute irrigation waters (up to 95% of water volume in some sinkhole ponds), whereas other points seem to be clearly determined by the hydrochemistry of the concentrated evaporitic aquifer groundwater (up to 50% of the water volume in some springs). The following reactions, previous or superimposed to mixing processes, explain the observed hydrochemistry in the studied area: dissolution of halite (NaCl), gypsum (CaSO4?2H2O)/anhydrite (CaSO4) and dolomite (CaMg(CO3)2), CO2(g) input and degassing and calcite (CaCO3) dissolution/precipitation. The modeling results suggest the existence of a large spatial variability in the composition of the evaporitic groundwater, mainly caused by large differences in the availability of halite in contact with the groundwater. Active subsidence associated with halite dissolution is expected to continue in the study area, together with the episodic increase of gypsum dissolution associated with the input of dilute irrigation waters.

  1. Hydrogeological studies in high mountains karst environment: the example of Picos de Europa (Spain)

    NASA Astrophysics Data System (ADS)

    Meléndez, Mónica; Ballesteros, Daniel; Jiménez-Sanchez, Montserrat; García-Sansegundo, Joaquín

    2015-04-01

    Karst aquifers are very vulnerable to contamination due their high infiltration coefficient, elevated hydraulic conductivity, high speed of circulation, and very low self-purification capacities. The functioning of that type of aquifer is quite complicated by the high heterogeneity and anisotropy of the karst and the presence of three different types of porosity. It is necessary to understand the functioning of a karst aquifer in order to protect and manage them properly. Therefore, it is necessary to develop working methods to establish the aquifer hydrodynamics, especially in high mountain areas with many methodological constrains (e. g. difficulty to access). The Picos de Europa karst aquifer, located in theNational Park of Picos de Europa (North Spain), presents a high environmental, geomorphological and hydrogeological value; it is included in the "Spanish geological contexts with global relevance" by the Law of Natural Heritage and Biodiversity of Spain, being considered as a Global Geosite by the Geological and Mining Institute of Spain. In addition, the karst massif is included in several figures of environmental protection, both at global and national levels. Hydrogeological and geomorphological research is developed together in this area under the GEOCAVE project (MAGRAMA-580/12 OAPN) and the "Investigación hidrogeológica en las masas de agua subterránea 012.014 Picos de Europa-Panes y 012.018 Alto Deva-Alto Cares. (IGME-73.3.00.41.00/2013)". The aim of this study is to characterize the hydrodynamics of the karst aquifer, considering the snow as an important component of the aquifer recharge. The proposed methodology includes the installation of an integrated pressure sensor and data logger for level and temperature measurement in two karst spring related to two groundwater bodies (GWB) with 86 and 14 km2 extension. The store of data to regular intervals with punctual values of discharge measures has provided, at least, an annual series of data in which level water differences varies from 4.5 m in the largest GWB to 1 m in the smallest one. The comparison of this data series with precipitation data allows to study the aquifer response to precipitation and to stablish the importance of the snow melting in the recharge of the aquifer.

  2. Hydrogeology and analysis of ground-water-flow system, Sagamore Marsh area, southeastern Massachusetts

    USGS Publications Warehouse

    Walter, D.A.; Masterson, J.P.; Barlow, P.M.

    1996-01-01

    A study of the hydrogeology and an analysis of the ground-water-flow system near Sagamore Marsh, southeastern Massachusetts, was undertaken with the cooperation of the U.S. Army Corps of Engineers. The purpose of the study was to improve the understanding of the current (1994-95) hydrogeologic conditions near the marsh and how the ground-water system might respond to proposed changes in the tidal-stage regime of streams that flood and drain the marsh. A 5-day aquifer test at a public-supply well adjacent to the marsh gave a transmissivity of the regional aquifer of 9,300 to 10,900 feet squared per day and a hydraulic conductivity of 181 to 213 feet per day, assuming a saturated thickness of the aquifer of 51.3 feet. The regional aquifer became unconfined near the pumped well during the test. The ratio of tidal ranges in the tidal channel to the ranges in the underlying aquifer at two sites (the lower and upper marsh) indicated aquifer diffusivities for the marsh sediments of 380 and 170 feet squared per day; these values correspond to hydraulic conductivities of 2.5 x 10-3 and 1.7 x 10-3 feet per day, respectively. The maximum distances from the tidal channel at the lower and upper marsh sites where tidal ranges would exceed 0.01 foot, as calculated from aquifer diffusivities and current (1995) tidal ranges in the tidal channels, were 24.4 and 26.7 feet, respectively. The maximum distances from the tidal channel where tidal pulses in the ground water would exceed 0.01 foot, using potential increased tidal stages resulting from proposed tidal-stage modifications and predicted by the U.S. Army Corps of Engineers, were 37.1 and 42.0 feet, respectively. A numerical model of the marsh and surrounding aquifer system indicated that the contributing area for the supply well adjacent to the marsh, for current (1994) pumping conditions, extends toward Great Herring Pond, about 2 miles northwest (upgradient) of the well, and does not extend beneath the marsh. The model also indicates that the predicted increases in tidal stages in the marsh will have a negligible effect on local ground-water levels.

  3. Hydrogeological effects of the latest Vogtland-NW Bohemian swarmquake period (August to December 2000)

    NASA Astrophysics Data System (ADS)

    Koch, Ulrich; Heinicke, Jens; Voßberg, Manuela

    2003-03-01

    Since 1989, hydrological, geochemical, and isotope investigations are accomplished at springs of the Upper Vogtland (Germany). The results give evidence of a fluidal response of the mineral spring 'Wettinquelle' (formerly: 'Radonquelle') Bad Brambach to the seismogenic processes in the swarm quake area of Nový Kostel (distance: 10 km), the most seismically active area in the region. In 1999, the measuring network was extended to groundwater drillings around the Wettinquelle, and multiparameter stations were installed at mofettes SW and S of the Nový Kostel area. Beginning at the end of August 2000, the strongest swarmquake series compared with the 1985/86 swarms occurred in the area of Nový Kostel. Hydrological and hydrochemical measurements show an anomalous behaviour of several parameters such as groundwater level, hydrostatic pressure, and free gas flow beginning at the end of July 2000, and partially, of a duration up to the first strong events of the autumn 2000 swarm. These precursor phenomena were the result of an increased fluidal pressure in the ground before the earthquakes. They were visible as higher static water levels in a gauge well and a stronger degassing of the mineral spring 'Wettinquelle'. The anomalies confirm our co-seismic hydrogeological observations of the last 10 years at Bad Brambach, as well as our model conception of anomaly generation due to fluidal pressure pulses [Pure. Appl. Geophys. 157 (2000) 1621]. Furthermore, co- and post-seismic effects of hydrological and geoelectrical parameters were recorded in the mofette area of Soos and Bublák (Czech Republic).

  4. Structural and hydrogeological features of a Lias carbonate aquifer in the Triffa Plain, NE Morocco

    NASA Astrophysics Data System (ADS)

    Sardinha, J.; Carneiro, J. F.; Zarhloule, Y.; Barkaoui, A.; Correia, A.; Boughriba, M.; Rimi, A.; El Houadi, B.

    2012-09-01

    The rising demand for water and the contamination of shallow water table aquifers has led authorities in NE Morocco to look for deeper groundwater resources in the Triffa Plain, namely in Lower Jurassic (Lias) dolomitic limestones. The liassic aquifer is of strategic importance for the development of the region, however, its hydrodynamic behaviour is poorly understood due to lack of hydrogeological data and block structure. This article presents a first effort towards understanding the structure and hydraulic behaviour of the aquifer. Exploration borehole data and results from geophysical campaigns were integrated into a GIS environment to build a preliminary model of the aquifer structure. The aquifer behaves as an unconfined aquifer in the northern part of the Béni Snassen Mountains (the recharge area), but as it dips to the north, it becomes confined by marls and shales of the Middle/Upper Jurassic. Even though piezometric level data are scarce, a tentative piezometric map was produced. Three blocks separated by NW-SE trending faults in a horst and graben structure, with distinct flow behaviours were identified: Berkane, Fezouane and Sidi Rahmoun blocks. Those blocks also show differences in hydraulic conductivity distribution. As a result of the reaction with the dolomitic limestones, the groundwater is of calcium-magnesium bicarbonate type. Groundwater temperature as measured in springs ranges from 29 °C to 37 °C in springs and constitutes a potential low enthalpy geothermal resource.

  5. Coupled semivariogram uncertainty of hydrogeological and geophysical data on capture zone uncertainty analysis

    USGS Publications Warehouse

    Rahman, A.; Tsai, F.T.-C.; White, C.D.; Willson, C.S.

    2008-01-01

    This study investigates capture zone uncertainty that relates to the coupled semivariogram uncertainty of hydrogeological and geophysical data. Semivariogram uncertainty is represented by the uncertainty in structural parameters (range, sill, and nugget). We used the beta distribution function to derive the prior distributions of structural parameters. The probability distributions of structural parameters were further updated through the Bayesian approach with the Gaussian likelihood functions. Cokriging of noncollocated pumping test data and electrical resistivity data was conducted to better estimate hydraulic conductivity through autosemivariograms and pseudo-cross-semivariogram. Sensitivities of capture zone variability with respect to the spatial variability of hydraulic conductivity, porosity and aquifer thickness were analyzed using ANOVA. The proposed methodology was applied to the analysis of capture zone uncertainty at the Chicot aquifer in Southwestern Louisiana, where a regional groundwater flow model was developed. MODFLOW-MODPATH was adopted to delineate the capture zone. The ANOVA results showed that both capture zone area and compactness were sensitive to hydraulic conductivity variation. We concluded that the capture zone uncertainty due to the semivariogram uncertainty is much higher than that due to the kriging uncertainty for given semivariograms. In other words, the sole use of conditional variances of kriging may greatly underestimate the flow response uncertainty. Semivariogram uncertainty should also be taken into account in the uncertainty analysis. ?? 2008 ASCE.

  6. Review: Some Low-Frequency Electrical Methods for Subsurface Characterization and Monitoring in Hydrogeology

    SciTech Connect

    Revil, Andre; Karaoulis, M.; Johnson, Timothy C.; Kemna, Andreas

    2011-01-01

    Low-frequency geoelectrical methods include mainly self-potential, resistivity, and induced polarization. These methods are commonly used to solve hydrogeological problems in the shallow subsurface and provide complementary information to each other and to in-situ measurements. The self-potential method is a passive measurement of the electrical response associated with the in-situ generation of current mainly due to the flow of pore water in porous media, a salinity gradient, and/or the concentration of redox-active species. It can be used to visualize groundwater flow patterns, to determine permeability, and to detect preferential flow paths. Electrical resistivity is dependent on the water content, the temperature, the salinity of the pore water, and the clay content and mineralogy. Induced polarization characterizes the ability of rocks to store electrical energy in terms of ion accumulations in the pore water. Electrical resistivity, time-domain and frequency-domain induced polarization methods can be used to image the permeability and the distribution of contaminants in the ground.

  7. Hydrogeological model of a high-energy geothermal field (Bouillante area, Guadeloupe, French West Indies)

    NASA Astrophysics Data System (ADS)

    Lachassagne, P.; Marechal, J. C.; Sanjuan, B.

    2009-11-01

    The Bouillante geothermal field provides about 8% of the annual electricity needs of the French West Indies island of Guadeloupe. It has been the subject of several studies covering various disciplines. A hydrogeological conceptual model of the field is proposed. The reservoir consists of two perpendicular sets of fractures and faults, related to major regional tectonic structures, which have been clogged near surface by self sealing. The heat exchanges of the reservoir with the outside are reduced, through thermal and hydraulic blanketing, to conductive transfers. Convection cells are active within the reservoir, ensuring its thermal and geochemical homogeneity. Heat exchange with the magmatic chamber is only conductive. The Na-Cl geothermal fluid in the reservoir is composed of 60% seawater and 40% freshwater and has reached a chemical equilibrium with a mineralogical assemblage at 250-260°C. Many arguments (equilibrium state, absence of tritium, low in/out fluxes, large reservoir volume) suggest a long residence time (>100 years) of the geothermal fluid. Three factors explain the existence and location of the geothermal field: a heat source (cooling hypovolcanic intrusion), a network of permeable fractures at the origin of the geothermal aquifer, and an impermeable surface cover, limiting the loss of energy and ensuring the durability of the field.

  8. Hydrogeology of the 200 Areas low-level burial grounds: An interim report: Volume 1, Text

    SciTech Connect

    Last, G.V.; Bjornstad, B.N.; Bergeron, M.P.; Wallace, D.W.; Newcomer, D.R.; Schramke, J.A.; Chamness, M.A.; Cline, C.S.; Airhart, S.P.; Wilbur, J.S.

    1989-01-01

    This report presents information derived from the installation of 35 ground-water monitoring wells around six low-level radioactive/hazardous waste burial grounds located in the 200 Areas of the Hanford Site in southeastern Washington State. This information was collected between May 20, 1987 and August 1, 1988. The contents of this report have been divided into two volumes. This volume contains the main text. Volume 2 contains the appendixes, including data and supporting information that verify content and results found in the main text. This report documents information collected by the Pacific Northwest Laboratory at the request of Westinghouse Hanford Company. Presented in this report are the preliminary interpretations of the hydrogeologic environment of six low-level burial grounds, which comprise four waste management areas (WMAs) located in the 200 Areas of the Hanford Site. This information and its accompanying interpretations were derived from sampling and testing activities associated with the construction of 35 ground-water monitoring wells as well as a multitude of previously existing boreholes. The new monitoring wells were installed as part of a ground-water monitoring program initiated in 1986. This ground-water monitoring program is based on requirements for interim status facilities in compliance with the Resource Conservation and Recovery Act (1976).

  9. Development of analytical and numerical models for the assessment and interpretation of hydrogeological field tests

    SciTech Connect

    Mironenko, V.A.; Rumynin, V.G.; Konosavsky, P.K.; Pozdniakov, S.P.; Shestakov, V.M.; Roshal, A.A.

    1994-07-01

    Mathematical models of the flow and tracer tests in fractured aquifers are being developed for the further study of radioactive wastes migration in round water at the Lake Area, which is associated with one of the waste disposal site in Russia. The choice of testing methods, tracer types (chemical or thermal) and the appropriate models are determined by the nature of the ongoing ground-water pollution processes and the hydrogeological features of the site under consideration. Special importance is attached to the increased density of wastes as well as to the possible redistribution of solutes both in the liquid phase and in the absorbed state (largely, on fracture surfaces). This allows for studying physical-and-chemical (hydrogeochemical) interaction parameters which are hard to obtain (considering a fractured structure of the rock mass) in laboratory. Moreover, a theoretical substantiation is being given to the field methods of studying the properties of a fractured stratum aimed at the further construction of the drainage system or the subsurface flow barrier (cutoff wall), as well as the monitoring system that will evaluate the reliability of these ground-water protection measures. The proposed mathematical models are based on a tight combination of analytical and numerical methods, the former being preferred in solving the principal (2D axisymmetrical) class of the problems. The choice of appropriate problems is based on the close feedback with subsequent field tests in the Lake Area. 63 refs.

  10. Description and hydrogeologic evaluation of nine hazardous-waste sites in Kansas 1984-86

    SciTech Connect

    Hart, R.J.; Spruill, T.B.

    1988-01-01

    Wastes generated at nine hazardous-waste sites in Kansas were disposed in open pits, 55-gal drums, or large storage tanks. These disposal methods have the potential to contaminate groundwater beneath the sites, the soil on the sites, and nearby surface water bodies. Various activities on the nine sites included production of diborane, transfer oil waste, production of soda ash, use of solvents for the manufacture of farm implements, reclamation of solvents and paints, oil-refinery wastes, meat packaging, and the manufacture and cleaning of tanker-truck tanks. Monitoring wells were installed upgradient and downgradient from the potential contamination source on each site. Strict decontamination procedures were followed to prevent cross contamination between well installations. Air-quality surveys were made on each site before other investigative procedures started. Hydrogeologic investigative techniques, such as terrain geophysical surveys, gamma-ray logs, and laboratory permeameter tests, were used. Groundwater level measurements provide data to determine the direction of flow. Groundwater contamination detected under the sites posed the greatest threat to the environment because of possible migration of contaminants by groundwater flow. Concentrations of volatile organic compounds, polynuclear aromatic hydrocarbons, and trace metals were detected in the groundwater at several of the sites. Many of the same compounds detected in the groundwater also were detected in soil and bed-material samples collected onsite or adjacent to the sites. Several contaminants were detected in background samples of groundwater and soil.

  11. Hydrogeologic data for the Blaine aquifer and associated units in southwestern Oklahoma and northwestern Texas

    USGS Publications Warehouse

    Runkle, D.L.; Bergman, D.L.; Fabian, R.S.

    1997-01-01

    This report is a compilation of hydrogeologic data collected for an areal ground-water investigation of the Blaine aquifer and associated units in southwestern Oklahoma and northwestern Texas. The study area includes parts of Greer, Harmon, and Jackson counties in Oklahoma and parts of Childress, Collingsworth, Hall, Hardeman, and Wilbarger counties in Texas. The Blaine aquifer consists of cavernous gypsum and dolomite beds. Water from the Blaine aquifer supports a local agriculture based mainly on irrigated cotton and wheat. The purpose of the study was to determine the availability, quantity, and quality of ground water from the Blaine aquifer and associated units. This report provides a reference for some of the data that was used as input into a computer ground-water flow model that simulates ground-water flow in the Blaine aquifer. The data in this report consists of: (1) Monthly or periodic water-level measurements in 134 wells; (2) daily mean water-level measurements for 11 wells equipped with water-level recorders; (3) daily total precipitation measurements from five precipitation gages; (4) low-flow stream-discharge measurements for 89 stream sites; (5) miscellaneous stream-discharge measurements at seven stream sites; (6) chemical analyses of surface water from 78 stream sites during low-flow periods; (7) chemical analyses of ground water from 41 wells; and (8) chemical analyses of runoff water collected at five sites.

  12. Developing conceptual hydrogeological model for Potsdam sandstones in southwestern Quebec, Canada

    USGS Publications Warehouse

    Nastev, Miroslav; Morin, R.; Godin, Rejean; Rouleau, Alain

    2008-01-01

    A hydrogeological study was conducted in Potsdam sandstones on the international border between Canada (Quebec) and the USA (New York). Two sandstone formations, arkose and conglomerate (base) and well-cemented quartz arenite (upper), underlie the study area and form the major regional aquifer unit. Glacial till, littoral sand and gravel, and marine silt and clay discontinuously overlie the aquifer. In both sandstone formations, sub-horizontal bedding planes are ubiquitous and display significant hydraulic conductivities that are orders of magnitude more permeable than the intact rock matrix. Aquifer tests demonstrate that the two formations have similar bulk hydrologic properties, with average hydraulic conductivities ranging from 2 ?? 10-5 to 4 ?? 10-5 m/s. However, due to their different lithologic and structural characteristics, these two sandstones impose rather different controls on groundwater flow patterns in the study area. Flow is sustained through two types of fracture networks: sub-horizontal, laterally extensive fractures in the basal sandstone, where hydraulic connectivity is very good horizontally but very poor vertically and each of the water-bearing bedding planes can be considered as a separate planar two-dimensional aquifer unit; and the more fractured and vertically jointed system found in the upper sandstone that promotes a more dispersed, three-dimensional movement of groundwater. ?? Springer-Verlag 2007.

  13. The hydrogeology of the Condamine River Alluvial Aquifer, Australia: a critical assessment

    NASA Astrophysics Data System (ADS)

    Dafny, Elad; Silburn, D. Mark

    2014-05-01

    The Condamine plain is an important agricultural zone in Australia with prominent irrigated cotton and grain crops. About one third of the irrigation water is pumped from the shallow alluvial aquifer, causing gross aquifer depletion over time. Over the last few decades, various hydrological, hydrochemical, and geological aspects of this aquifer and the overlying floodplain (including soil properties) have been investigated and used to construct the conceptual understanding and numerical models for management of this resource. Yet, the water balance of the aquifer is still far from resolved, and the geological contact between the alluvial sediments and underlying bedrock is yet to be categorically defined, to mention two major uncertainties. This report collates up-to-date knowledge of different disciplines, critically evaluates the accepted hydrogeological conventions, highlights key knowledge gaps, and suggests strategies for future research. Among recommendations are (1) development of numerical flow and solute transport models for the natural (i.e. pre-developed) period, (2) analysis of groundwater for isotopic composition and presence of pesticides, CFCs and PPCPs, and (3) use of stochastic approaches to characterize the hydraulic properties of the alluvial sediments. These and other proposed measures are relevant also to other alluvial aquifers which suffer from similar fundamental uncertainties.

  14. Developing conceptual hydrogeological model for Potsdam sandstones in southwestern Quebec, Canada

    NASA Astrophysics Data System (ADS)

    Nastev, M.; Morin, R.; Godin, R.; Rouleau, A.

    2008-03-01

    A hydrogeological study was conducted in Potsdam sandstones on the international border between Canada (Quebec) and the USA (New York). Two sandstone formations, arkose and conglomerate (base) and well-cemented quartz arenite (upper), underlie the study area and form the major regional aquifer unit. Glacial till, littoral sand and gravel, and marine silt and clay discontinuously overlie the aquifer. In both sandstone formations, sub-horizontal bedding planes are ubiquitous and display significant hydraulic conductivities that are orders of magnitude more permeable than the intact rock matrix. Aquifer tests demonstrate that the two formations have similar bulk hydrologic properties, with average hydraulic conductivities ranging from 2 × 10-5 to 4 × 10-5 m/s. However, due to their different lithologic and structural characteristics, these two sandstones impose rather different controls on groundwater flow patterns in the study area. Flow is sustained through two types of fracture networks: sub-horizontal, laterally extensive fractures in the basal sandstone, where hydraulic connectivity is very good horizontally but very poor vertically and each of the water-bearing bedding planes can be considered as a separate planar two-dimensional aquifer unit; and the more fractured and vertically jointed system found in the upper sandstone that promotes a more dispersed, three-dimensional movement of groundwater.

  15. The Geologic and Hydrogeologic Setting of the Waste Isolation Pilot Plant

    SciTech Connect

    Swift, P.N.; Corbet, T.F.

    1999-03-04

    The Waste Isolation Pilot Plant (WIPP) is a mined repository constructed by the US Department of Energy for the permanent disposal of transuranic wastes generated since 1970 by activities related to national defense. The WIPP is located 42 km east of Carlsbad, New Mexico, in bedded salt (primarily halite) of the Late Permian (approximately 255 million years old) Salado Formation 655 m below the land surface. Characterization of the site began in the mid-1970s. Construction of the underground disposal facilities began in the early 1980s, and the facility received final certification from the US Environmental Protection Agency in May 1998. Disposal operations are planned to begin following receipt of a final permit from the State of New Mexico and resolution of legal issues. Like other proposed geologic repositories for radioactive waste, the WIPP relies on a combination of engineered and natural barriers to isolate the waste from the biosphere. Engineered barriers at the WIPP, including the seals that will be emplaced in the access shafts when the facility is decommissioned, are discussed in the context of facility design elsewhere in this volume. Physical properties of the natural barriers that contribute to the isolation of radionuclides are discussed here in the context of the physiographic, geologic, and hydrogeologic setting of the site.

  16. Limitations of pump and treat remediation in a common New England hydrogeologic environment

    SciTech Connect

    Maclean, D.A.; Marin, P.A. )

    1993-03-01

    A common hydrogeologic setting in New England consists of a thin layer of permeable glacial outwash (0--20 ft.) which overlays dense contact till deposited directly by glacial ice. These settings provide quite a challenge for hydrogeologists attempting to contain and remediate ground water contamination. Average linear migration velocities are often high because of the high permeability of the outwash (ranging from 1 to 100 ft/day or more). Spills in these environments can quickly create contaminated ground water plumes of large size threatening drinking water wells and other sensitive receptors. Pump and treat'' systems (consisting of a pumped recovery well with a treatment system to clean pumped water prior to discharge) are commonly installed in these environments, but they often fail to contain and remediate ground water contamination. Data from several case studies and from analytical models used to evaluate pump and treat options demonstrate that pumping rates are limited by the available drawdown in the shallow outwash unit and by the low hydraulic conductivity of the lower till unit. Therefore, pump and treat systems often fail to develop effective capture zones in these environments even though highly permeable outwash sands are present. Combined air sparging and soil venting techniques (AS/SV) may provide an effective alternative to pump and treat remediation systems in these environments. Data from cases studies show that AS/SV can remove more contaminant mass than pump and treat while treating soil and ground water in place.

  17. Hydrogeology of the Little Spokane River Basin, Spokane, Stevens, and Pend Oreille Counties, Washington

    USGS Publications Warehouse

    Kahle, Sue C.; Olsen, Theresa D.; Fasser, Elisabeth T.

    2013-01-01

    A study of the hydrogeologic framework of the Little Spokane River Basin was conducted to identify and describe the principal hydrogeologic units in the study area, their hydraulic characteristics, and general directions of groundwater movement. The Little Spokane River Basin includes an area of 679 square miles in northeastern Washington State covering parts of Spokane, Stevens, and Pend Oreille Counties. The groundwater system consists of unconsolidated sedimentary deposits and isolated, remnant basalt layers overlying crystalline bedrock. In 1976, a water resources program for the Little Spokane River was adopted into rule by the State of Washington, setting instream flows for the river and closing its tributaries to further uses. Spokane County representatives are concerned about the effects that additional groundwater development within the basin might have on the Little Spokane River and on existing groundwater resources. Information provided by this study will be used in future investigations to evaluate the effects of potential increases in groundwater withdrawals on groundwater and surface-water resources in the basin. The hydrogeologic framework consists of eight hydrogeologic units: the Upper aquifer, Upper confining unit, Lower aquifers, Lower confining unit, Wanapum basalt unit, Latah unit, Grande Ronde basalt unit, and Bedrock. The Upper aquifer is composed mostly of sand and gravel and varies in thickness from 4 to 360 ft, with an average thickness of 70 ft. The aquifer is generally finer grained in areas farther from main outwash channels. The estimated horizontal hydraulic conductivity ranges from 4.4 to 410,000 feet per day (ft/d), with a median hydraulic conductivity of 900 ft/d. The Upper confining unit is a low-permeability unit consisting mostly of silt and clay, and varies in thickness from 5 to 400 ft, with an average thickness of 100 ft. The estimated horizontal hydraulic conductivity ranges from 0.5 to 5,600 ft/d, with a median hydraulic conductivity of 8.2 ft/d. The Lower aquifers unit consists of localized confined aquifers or lenses consisting mostly of sand that occur at depth in various places in the basin; thickness of the unit ranges from 8 to 150 ft, with an average thickness of 50 ft. The Lower confining unit is a low-permeability unit consisting mostly of silt and clay; thickness of the unit ranges from 35 to 310 ft, with an average thickness of 130 ft. The Wanapum basalt unit includes the Wanapum Basalt of the Columbia River Basalt Group, thin sedimentary interbeds, and, in some places, overlying loess. The unit occurs as isolated remnants on the basalt bluffs in the study area and ranges in thickness from 7 to 140 ft, with an average thickness of 60 ft. The Latah unit is a mostly low-permeability unit consisting of silt, clay, and sand that underlies and is interbedded with the basalt units. The Latah unit ranges in thickness from 10 to 700 ft, with an average thickness of 250 ft. The estimated horizontal hydraulic conductivity ranges from 0.19 to 15 ft/d, with a median hydraulic conductivity of 0.56 ft/d. The Grande Ronde unit includes the Grande Ronde Basalt of the Columbia River Basalt Group and sedimentary interbeds. Unit thickness ranges from 30 to 260 ft, with an average thickness of 140 ft. The estimated horizontal hydraulic conductivity ranges from 0.03 to 13 ft/d, with a median hydraulic conductivity of 2.9 ft/d. The Bedrock unit is the only available source of groundwater where overlying sediments are absent or insufficiently saturated. The estimated horizontal hydraulic conductivity ranges from 0.01 to 5,000 ft/d, with a median hydraulic conductivity of 1.4 ft/d. The altitude of the buried bedrock surface ranges from about 2,200 ft to about 1,200 ft. Groundwater movement in the Little Spokane River Basin mimics the surface-water drainage pattern of the basin, moving from the topographically high tributary-basin areas toward the topographically lower valley floors. Water-level altitudes range from more than 2,700 ft to about 1,500 ft near the basin’s outlet.

  18. Hydrogeological relationships of sandy deposits: modeling of two-dimensional unsaturated water and pesticide transport.

    PubMed

    Iversen, Bo V; van der Keur, Peter; Vosgerau, Henrik

    2008-01-01

    Prediction of the movement of water and solutes in the vadose zone requires information on the distribution of spatial trends and heterogeneities in porous media. The present study describes different lithofacies origination mainly from glaciofluvial deposits. Among different lithofacies, hydrological relationships were investigated. By means of a two-dimensional hydrological model it was evaluated how the flow of water and leaching of metribuzin (4-amino-6-tert-butyl-4,5-dihydro-3-methylthio-1,2,4-triazin-5-one) was affected. Two selected large outcrop sections consisting of glacial outwash deposits were used in the modeling study. Eleven different lithofacies were distinguished and described in terms of texture distribution, sorting, bedding style, and external boundaries based on excavated soil profiles from 27 locations representing seven predominantly sandy landforms in Denmark. Undisturbed soil columns were sampled from each of the lithofacies and brought to the laboratory to be analyzed. With respect to their soil hydraulic properties, the different lithofacies formed four different hydrofacies having relatively homogeneous, hydrogeological properties. Two large outcrop sections from one of the locations (a gravel pit) located near the terminal moraine of the former Weichsel glacier were used for the HYDRUS-2D modeling. Modeling results revealed that the spatial distribution of sedimentary bodies affected water flow and the leaching of metribuzin. PMID:18689752

  19. Reliability, sensitivity, and uncertainty of reservoir performance under climate variability in basins with different hydrogeologic settings

    NASA Astrophysics Data System (ADS)

    Mateus, C.; Tullos, D.

    2014-12-01

    This study investigated how reservoir performance varied across different hydrogeologic settings and under plausible future climate scenarios. The study was conducted in the Santiam River basin, OR, USA, comparing the North Santiam basin (NSB), with high permeability and extensive groundwater storage, and the South Santiam basin (SSB), with low permeability, little groundwater storage, and rapid runoff response. We applied projections of future temperature and precipitation from global climate models to a rainfall-runoff model, coupled with a formal Bayesian uncertainty analysis, to project future inflow hydrographs as inputs to a reservoir operations model. The performance of reservoir operations was evaluated as the reliability in meeting flood management, spring and summer environmental flows, and hydropower generation objectives. Despite projected increases in winter flows and decreases in summer flows, results suggested little evidence of a response in reservoir operation performance to a warming climate, with the exception of summer flow targets in the SSB. Independent of climate impacts, historical prioritization of reservoir operations appeared to impact reliability, suggesting areas where operation performance may be improved. Results also highlighted how hydrologic uncertainty is likely to complicate planning for climate change in basins with substantial groundwater interactions.

  20. Description and hydrogeologic evaluation of nine hazardous-waste sites in Kansas, 1984-86

    USGS Publications Warehouse

    Hart, R.J.; Spruill, T.B.

    1988-01-01

    Wastes generated at nine hazardous-waste sites in Kansas were disposed in open pits, 55-gal drums, or large storage tanks. These disposal methods have the potential to contaminate groundwater beneath the sites, the soil on the sites, and nearby surface water bodies. Various activities on the nine sites included production of diborane, transformer oil waste, production of soda ash, use of solvents for the manufacture of farm implements, reclamation of solvents and paints, oil-refinery wastes, meat packaging, and the manufacture and cleaning of tanker-truck tanks. Monitoring wells were installed upgradient and downgradient from the potential contamination source on each site. Strict decontamination procedures were followed to prevent cross contamination between well installations. Air-quality surveys were made on each site before other investigative procedures started. Hydrogeologic investigative techniques, such as terrain geophysical surveys, gamma-ray logs, and laboratory permeameter tests, were used. Groundwater level measurements provide data to determine the direction of flow. Groundwater contamination detected under the sites posed the greatest threat to the environment because of possible migration of contaminants by groundwater flow. Concentrations of volatile organic compounds, polynuclear aromatic hydrocarbons, and trace metals were detected in the groundwater at several of the sites. Many of the same compounds detected in the groundwater also were detected in soil and bed-material samples collected onsite or adjacent to the sites. Several contaminants were detected in background samples of groundwater and soil. (USGS)

  1. Beyond hydrogeologic evidence: challenging the current assumptions about salinity processes in the Corangamite region, Australia

    NASA Astrophysics Data System (ADS)

    Dahlhaus, P. G.; Cox, J. W.; Simmons, C. T.; Smitt, C. M.

    2008-11-01

    In keeping with the standard scientific methods, investigations of salinity processes focus on the collection and interpretation of contemporary scientific data. However, using multiple lines of evidence from non-hydrogeologic sources such as geomorphic, archaeological and historical records can substantially add value to the scientific investigations. By using such evidence, the validity of the assumptions about salinity processes in Australian landscapes is challenged, especially the assumption that the clearing of native vegetation has resulted in rising saline groundwater in all landscapes. In the Corangamite region of south-west Victoria, salinity has been an episodic feature of the landscapes throughout the Quaternary and was present at the time of the Aboriginal inhabitants and the first pastoral settlement by Europeans. Although surface-water salinity has increased in some waterways and the area of salinised land has expanded in some landscapes, there is no recorded evidence found which supports significant rises in groundwater following widespread land-use change. In many areas, salinity is an inherent component of the region’s landscapes, and sustains world-class environmental assets that require appropriate salinity levels for their ecological health. Managing salinity requires understanding the specific salinity processes in each landscape.

  2. Hydrogeologic framework of U.S. Marine Corps Base at Camp Lejeune, North Carolina

    USGS Publications Warehouse

    Cardinell, A.P., Jr.; Berg, S.A.; Lloyd, O.B., Jr.

    1993-01-01

    The hydrogeologic framework at Camp Lejeune consists of the surficial, Castle Hayne, Beaufort, and Peedee aquifers and intervening confining units. The Castle Hayne aquifer furnishes about 7 million gallons of water per day to Camp Lejeune, but the surficial, Beaufort, and Peedee aquifers, which contain freshwater in places, are not used for supply. The Castle Hayne aquifer is composed of 60 to 90 percent sand and limestone with clay and silt beds, and ranges from 156 to 400 feet thick. Hydraulic conductivity of the aquifer ranges from 14 to 91 feet per day. The Castle Hayne confining unit, which overlies the Castle Hayne aquifer, is composed of silt and sandy clay and averages 9 feet thick where present. This confining unit is incised by the New River and its tributaries, as well as some paleochannels. The effects of pumping from the Castle Hayne aquifer have not significantly affected natural head gradients in the aquifer. However, the potential exists for lateral migration of saltwater where wells are located near streams or paleochannels that have incised the confining unit. Except for one measurement of 960 milligrams per liter chloride in a water sample from the bottom of the Castle Hayne aquifer, dissolved-chloride concentrations in water samples from the Castle Hayne aquifer were less than 120 milligrams per liter. It is not known whether this occurrence of saltwater in the Castle Hayne aquifer is widespread or localized, but its presence indicates a potential for upward movement of saltwater beneath pumped wells.

  3. Towards identifying data needs for a regional hydrogeologic contamination study using multiple realization simulations

    SciTech Connect

    McCord, J.; Treadway, A.

    1993-11-01

    This paper describes a stochastic, distributed parameter simulation approach which is being used to identify/prioritize data collection activities for a 250 km{sup 2} region containing numerous potential contamination sites. The region is located in the southeast part of the Albuquerque Basin in central New Mexico, USA. The Basin is part of the Rio Grande Trough, a large graben with large vertical displacements between the central basin and the adjacent highlands. Numerous potential human receptors are located around the periphery of the region, and it is the desired to have a groundwater monitoring well network.which can help provide early detection of contamination plumes as well as provide relevant data on the regional hydrogeologic framework. A 2D numerical model of the regional basin-fill aquifer is developed with explicit recognition of uncertainties in flow parameter spatial distributions. We account for uncertainty in the parameter field through Monte Carlo simulation. To reduce the computational burden of multiple realization simulation, we employ a linearized stochastic model which permits cosimulation of transmissivity and head fields, conditioning on both transmissivity and head. The locations of selected contamination sites within the region then are overlaid on the simulation results, and flow paths and groundwater travel times from the contamination sites are assessed using sensitivity analysis to identify preferred locations for collection of additional data and the types of data which should be collected (e.g., head, transmissivity, or geologic cores).

  4. Hydrogeologic and hydrogeochemical assessment of geothermal fluids in the Pyramid Lake area, Washoe country, Nevada

    SciTech Connect

    Ojiambo, S. Bwire

    1992-01-01

    This paper evaluates the hydrogeological and hydrogeochemical characteristics of the geothermal fluids in the Pyramid Lake area using data from existing published and unpublished reports on springs, challow and deep wells in the area. Four geochemical provinces, namely, chloride, bicarbonate, suphate and nixed chloride-bicarbonate have been identified. Chloride waters are found in known geothermal areas. Two subsurface water recharge zones which reed the shallow and deep geothermal systems are proposed. These are the Virginia Mountains and their Northern extension and the Fox and Lake Ranges. Tertiary and Quaternary faulting systems in these mountains and Ranges act as heat conduits for geothermal fluids. The Needle Rocks geothermal system is postulated to be deeper than the San Emidio system. A connection between the Needle Rocks system and the Pyramid and Anaho islands warm springs is not clear from this study because of lack of chemical data from these islands. More systematic measurements of static water levels, temperatures, well lithology, water chemistry and isotopes data are recommended to enable better understanding of the geothermal systems in the area.

  5. Hydrogeological factors affecting the multiple plumes of chlorinated contaminants in an industrial complex, Wonju, Korea

    NASA Astrophysics Data System (ADS)

    Yang, J.; Kaown, D.; Lee, H.; Lee, K.

    2010-12-01

    Apparent plume attenuations of multiple chlorinated contaminants such as TCE, carbon tetrachloride, and its daughter products at an industrial complex, Wonju, Korea were examined through various hydraulic tests and six rounds of groundwater quality analyses. Aquifer media properties and hydrogeologic factors affecting the distribution and attenuation of multiple contaminants were investigated and key attributes were evaluated. The study area has vertically heterogeneous properties from top alluvial layer to crystalline rocks while the weathered fractured layer above intact Jurassic biotite granite acts as the main layer for groundwater flow and aqueous phase multiple contaminants migration. Aerial heterogeneity in surface conditions plays an important role for groundwater recharge because the industrial complex is mostly paved by asphalt and concrete. Due to limited recharge area and concentrated precipitation in summer season, seasonal effects of contaminant plume distribution diminish as the distance increase from the area of recharge. This study analyzed how differently the solute and contaminant concentrations response to the seasonal recharge. For the analyses, the study site was divided into three zones and four transects were established. Groundwater and solute mass balances were estimated by computing groundwater and solute mass flux through transects. The effects of groundwater pumping, groundwater flow and contaminant degradation were examined to simulate the solutes and contaminant concentrations. General tendency of the water quality and contaminant concentration were reproducible with the effects of major components such as groundwater recharge, pumping and estimated degradation rate.

  6. Review: Some low-frequency electrical methods for subsurface characterization and monitoring in hydrogeology

    SciTech Connect

    Revil, Andre; Karaoulis, M.; Johnson, Timothy C.; Kemna, Andreas

    2012-02-10

    Low-frequency geoelectrical methods include mainly self-potential, resistivity, and induced polarization techniques, which have potential inmany environmental and hydrogeological applications. They provide complementary information to each other and to in-situ measurements. The self-potential method is a passive measurement of the electrical response associated with the in-situ generation of electrical current due to the flow of pore water in porous media, a salinity gradient, and/or the concentration of redoxactive species. Under some conditions, this method can be used to visualize groundwater flow, to determine permeability, and to detect preferential flow paths. Electrical resistivity is dependent on the water content, the temperature, the salinity of the pore water, and the clay content and mineralogy. Time-lapse resistivity can be used to assess the permeability and dispersivity distributions and to monitor contaminant plumes. Induced polarization characterizes the ability of rocks to reversibly store electrical energy. It can be used to image permeability and to monitor chemistry of the pore water-minerals interface. These geophysical methods, reviewed in this paper, should always be used in concert with additional in-situ measurements (e.g. in-situ pumping tests, chemical measurements of the pore water), for instance through joint inversion schemes, which is an area of fertile on-going research.

  7. Influence of ancient thrust faults on the hydrogeology of the Blue Ridge Province.

    PubMed

    Seaton, William J; Burbey, Thomas J

    2005-01-01

    The Blue Ridge Province contains ubiquitous northeast-southwest-trending thrust faults or smaller thrust "slivers" that greatly impact the nature and character of ground water flow in this region. Detailed investigations at a field site in Floyd County, Virginia, indicate that high-permeability zones occur in the brittle crystalline rocks above these thrust faults. Surface and borehole geophysics, aquifer tests, and chlorofluorocarbon and geochemical data reveal that the shallow saprolite aquifer is separated from the deeper fault-zone aquifer by a low-fracture permeability bedrock confining unit, the hydraulic conductivity of which has been estimated to be six orders of magnitude less than the conductivity of the fault zones at the test site. Within the Blue Ridge Province, these fault zones can occur at depths of 300 m or more, can contain a significant amount of storage, and yield significant quantities of water to wells. Furthermore, it is expected that these faults may compartmentalize the deep aquifer system. Recharge to and discharge from the deep aquifer occurs by slow leakage through the confining unit or through localized breach zones that occur where quartz accumulated in high concentrations during metamorphism and later became extensively fractured during episodes of deformation. The results of this investigation stress the importance of thrust faults in this region and suggest that hydrogeologic models for the Blue Ridge Province include these ancient structural features. Faults in crystalline-rock environments may not only influence the hydrology, they may dominate the flow characteristics of a region. PMID:15882322

  8. Hydrogeological studies for radiological monitoring of shallow groundwater in the Eurex plant of Saluggia (Vercelli, Italy).

    PubMed

    Iezzi, S; Imperi, M; Rosati, M; Ventura, G

    2009-12-01

    In 2004, contaminated water was found inside the safety interspace around the spent fuel pool; therefore, an ample monitoring programme of the structure, soils and shallow groundwater was started in order to detect any radioactive leakage into the environment. A first group of piezometers was installed. In the one nearest to the pool, an anomalous activity of (90)Sr ( approximately 10(-2) Bq l(-1)) was found, calling for the following actions: gradual enlarging of the monitoring network, implementation of in situ permeability tests and groundwater tracer test and study of groundwater mobility of the main radionuclides contained in the pool water: (90)Sr, (137)Cs, (241)Am and (239/240)Pu. Because (90)Sr is the only artificial radionuclide detected in groundwater, this study mainly focused on this one. All the investigations demonstrated that (90)Sr coming from the pool is not detectable any longer just some tens of metres from the building and allow the correlation of (90)Sr concentration to flow and water-table fluctuations. Moreover, such a wide mass of hydrogeological and radiological data allows the estimation of an environmental value for environmental radiological significance. PMID:19889799

  9. Design of monitor wells, hydrogeology, and ground-water quality beneath Country Pond, Kingston, New Hampshire

    USGS Publications Warehouse

    Mack, T.J.

    1995-01-01

    Ten monitoring well were installed in May 1993 to collect data on the hydrogeology and ground-water quality beneath Country Pond, in Kingston, New Hampshire. Monitoring wells were installed 4 to 48 feet beneath the pond surface in stratified drift that was up to 40 feet thick. The stratified drift is overlain by up to 35 feet of fine-grained, predominantly organic, lake-bottom sediment. The potentiometric head in the aquifer was at or above the pond surface and up to 0.8 foot above the pond surface at one location. Water-quality analyses detected numerous volatile organic compounds including chloroethane, benzene, dichlorobenzenes, and 1,1-dichloroethane at maximum concentrations of 110, 43, 54, and 92 mg/L, respectively. The maximum concentration of total volatile organic compounds detected in ground water from a monitoring well was 550 mg/L in November 1993. Ground-water samples with high concentrations of volatile organic compounds also had elevated specific conductances indicating the presence of other non-organic contaminants. Water-quality analyses indicate that a plume of contaminated ground water extends at least 300 feet in a northeast direction beneath the pond.

  10. Transport properties of iodide in a sandy aquifer: Hydrogeological modelling and field tracer tests

    NASA Astrophysics Data System (ADS)

    Razafindratsima, Stephen; Péron, Olivier; Piscitelli, Anne; Gégout, Claire; Schneider, Vincent; Barbecot, Florent; Giffaut, Eric; Robinet, Jean-Charles; Le Cointe, Pierre; Montavon, Gilles

    2015-01-01

    The release of radioactive iodine into geological media from nuclear waste disposal is an issue that has to be considered since iodine is a biophilic element. 129I is, with 99Tc, one of the two long-lived radionuclides that have the highest mobility in radioactive waste disposal. Within this context, iodide retardation is still a matter of debate. A low value of the retardation factor is generally accepted in soils without organic matter, but the possibility for sorption cannot be completely ruled out. Since isotopic exchange with naturally occurring iodine is one of the main potential sorption mechanisms, site-specific retention parameters are needed. In the present paper, we study iodide transport in a sandy aquifer. A hydrogeological model was built to fit deuterium, bromide and iodide breakthrough data from in situ tracer test experiments. Within the precision range of the fitting, iodide is excluded from 2.5% of the effective porosity by anionic exclusion and presents a field retention factor (Kd) lower than 0.025 L/kg.

  11. Hydrogeology of an alpine rockfall aquifer system and its role in flood attenuation and maintaining baseflow

    NASA Astrophysics Data System (ADS)

    Lauber, U.; Kotyla, P.; Morche, D.; Goldscheider, N.

    2014-06-01

    The frequency and intensity of extreme hydrological events in alpine regions is projected to increase with climate change. The goal of this study was to better understand the functioning of aquifers composed of complex alluvial and rockfall deposits in alpine valleys and to quantify the role of these natural storage spaces in flood attenuation and baseflow maintenance. Geomorphological and hydrogeological mapping, tracer tests, and continuous flow measurements were conducted in the Reintal valley (German Alps), where runoff from a karst spring infiltrates into a series of postglacial alluvial/rockfall aquifers. During high-flow conditions, groundwater velocities of 30 m h-1 were determined along 500 m; hydrograph analyses revealed short lag times (5 h) between discharge peaks upstream and downstream from the aquifer series; the maximum discharge ratio downstream (22) and the peak recession coefficient (0.196 d-1) are low compared with other alpine catchments. During low-flow conditions, the underground flow path length increased to 2 km and groundwater velocities decreased to 13 m h-1. Downstream hydrographs revealed a delayed discharge response after 101 h and peaks dampened by a factor of 1.5. These results indicate that alluvial/rockfall aquifers might play an important role in the flow regime and attenuation of floods in alpine regions.

  12. Hydrogeology of an Alpine rockfall aquifer system and its role in flood attenuation and maintaining baseflow

    NASA Astrophysics Data System (ADS)

    Lauber, U.; Kotyla, P.; Morche, D.; Goldscheider, N.

    2014-11-01

    The frequency and intensity of extreme hydrological events in Alpine regions is projected to increase with climate change. The goal of this study is to better understand the functioning of aquifers composed of complex alluvial and rockfall deposits in Alpine valleys and to quantify the role of these natural storage spaces in flood attenuation and baseflow maintenance. Geomorphological and hydrogeological mapping, tracer tests, and continuous flow measurements were conducted in the Reintal (German Alps), where runoff from a karst spring infiltrates a series of postglacial alluvial/rockfall aquifers. During high-flow conditions, groundwater velocities of 30 m h-1 were determined along 500 m; hydrograph analyses revealed short lag times (5 h) between discharge peaks upstream and downstream from the aquifer series; the maximum discharge ratio downstream (22) and the peak recession coefficient (0.196 d-1) are low compared with other Alpine catchments. During low-flow conditions, the underground flow path length increased to 2 km and groundwater velocities decreased to 13 m h-1. Downstream hydrographs revealed a delayed discharge response after 101 h and peaks damped by a factor of 1.5. These results indicate that alluvial/rockfall aquifers might play an important role in the flow regime and attenuation of floods in Alpine regions.

  13. Probability distributions of hydraulic conductivity for the hydrogeologic units of the Death Valley regional ground-water flow system, Nevada and California

    SciTech Connect

    Belcher, W.R.; Sweetkind, D.S.; Elliott, P.E.

    2002-11-19

    The use of geologic information such as lithology and rock properties is important to constrain conceptual and numerical hydrogeologic models. This geologic information is difficult to apply explicitly to numerical modeling and analyses because it tends to be qualitative rather than quantitative. This study uses a compilation of hydraulic-conductivity measurements to derive estimates of the probability distributions for several hydrogeologic units within the Death Valley regional ground-water flow system, a geologically and hydrologicaly complex region underlain by basin-fill sediments, volcanic, intrusive, sedimentary, and metamorphic rocks. Probability distributions of hydraulic conductivity for general rock types have been studied previously; however, this study provides more detailed definition of hydrogeologic units based on lithostratigraphy, lithology, alteration, and fracturing and compares the probability distributions to the aquifer test data. Results suggest that these probability distributions can be used for studies involving, for example, numerical flow modeling, recharge, evapotranspiration, and rainfall runoff. These probability distributions can be used for such studies involving the hydrogeologic units in the region, as well as for similar rock types elsewhere. Within the study area, fracturing appears to have the greatest influence on the hydraulic conductivity of carbonate bedrock hydrogeologic units. Similar to earlier studies, we find that alteration and welding in the Tertiary volcanic rocks greatly influence conductivity. As alteration increases, hydraulic conductivity tends to decrease. Increasing degrees of welding appears to increase hydraulic conductivity because welding increases the brittleness of the volcanic rocks, thus increasing the amount of fracturing.

  14. Identification and Characterization of Hydrogeologic Units at the Nevada Test Site Using Geophysical Logs: Examples from the Underground Test Area Project

    SciTech Connect

    Lance Prothro, Sigmund Drellack, Margaret Townsend

    2009-03-25

    The diverse and complex geology of the Nevada Test Site region makes for a challenging environment for identifying and characterizing hydrogeologic units penetrated by wells drilled for the U.S. Department of Energy, National Nuclear Security Administration, Underground Test Area (UGTA) Environmental Restoration Sub-Project. Fortunately, UGTA geoscientists have access to large and robust sets of subsurface geologic data, as well as a large historical knowledge base of subsurface geological analyses acquired mainly during the underground nuclear weapons testing program. Of particular importance to the accurate identification and characterization of hydrogeologic units in UGTA boreholes are the data and interpretation principles associated with geophysical well logs. Although most UGTA participants and stakeholders are probably familiar with drill hole data such as drill core and cuttings, they may be less familiar with the use of geophysical logs; this document is meant to serve as a primer on the use of geophysical logs in the UGTA project. Standard geophysical logging tools used in the UGTA project to identify and characterize hydrogeologic units are described, and basic interpretation principles and techniques are explained. Numerous examples of geophysical log data from a variety of hydrogeologic units encountered in UGTA wells are presented to highlight the use and value of geophysical logs in the accurate hydrogeologic characterization of UGTA wells.

  15. Hydrogeological and isotope mapping of the karstic Savica River (NW Slovenia)

    NASA Astrophysics Data System (ADS)

    Bren?i?, Mihael; Vre?a, Polona

    2015-04-01

    Mapping is important part of the hydrogeological terrain investigations, especially when spatial and temporal relations are not known precisely. There are many different methods available; among them not least important is careful visual inspection of the stream and its stream bed at regular intervals with the aim to detect phenomena which reflect surface water groundwater interactions. In parallel with the inspection various measurements can be performed. Together with usual water electro conductivity and water temperature we tested complimentary information which can be obtained with the concomitant regular sampling for ?18O determination in the river water course. Combination of all these information proved to be very useful in obtaining spatial trends in river characteristics and to determine relations between its water balance components. Testing of the methodology of hydrogeological mapping with the means of isotopes on the karstic Savica River during low flow period where water balance relations between its tributaries were not known before demonstrate the usefulness of the applied approach. Savica River is positioned in the north-west part of Slovenia in the centre of Triglav national Park which covers large part of East Julian Alps. River represents the main recharge of the Bohinj Lake, largest Slovenian natural lake. Savica River is short with the length of only 4.0 km and consists of two tributaries in the upper part; Mala Savica coming from the west and Velika Savica coming from the north-west. The first is recharged from several water caves of various lengths in which water level depends on hydrological conditions, consequently terminal end of the water in its riverbed part changes during the year. The second tributary is recharged from the 510 m long karstic cave with the entrance at 836 m a.s.l. where water disappears over 75 m high famous and picturesque waterfall. Geology of the catchment is predominantly formed by Dachstein limestone of Upper Triassic age subordinated by small number of dolomite beds. In the period between years 1954 and 2012 was average discharge at the gauging station Savica Ukanc 5.08 m3/s. At the gauging profile riverbed is occasionally reported as dry and maximum measured discharge was 138 m3/s. Based on the three sampling campaigns performed at low water conditions when each time between 35 and 40 samples were taken, we were able to estimate relations between various Savica River components. During low water period Mala Savica defined presents between 12 % and 17 % of the total outflow from the total Savica recharge area. Velika Savica in its complete water course represents between 78 % and 82 % of the total outflow. There is also small part recharging in the area between the confluence of Velika Savica and Mala Savica and confluence of Savica with Bohinj Lake; this part represents from 3 % to 5 %, however estimations are very rough and probably prone to large error. Estimated relations are based on the rough calculations but represent important step forward in the understanding of complex Savica River system. Until now no data was available on the amount and share of Velika Savica and Mala Savica to the total outflow from the vast karstic recharge area on high mountainous plateau. Mapping campaigns along the whole river were performed at low to moderate hydrological conditions; therefore results cannot be transferred to the all possible hydrological conditions. However, similar results obtained during three seasons with slightly different discharge regimes indicate that the spatial relations are relatively stable. Results are important for further investigations of Savica River system. Such information can help to discern hydrogeologicaly important points along the river course and based on them we can focus on more detailed observations at particular sites. In the future they will help us in better understanding of hydrograph components and better understanding of the functioning of karstic aquifer draining through Savica springs and direct inflows of groundwater into the rive

  16. A near real time scenario at regional scale for the hydrogeological risk

    NASA Astrophysics Data System (ADS)

    Ponziani, F.; Stelluti, M.; Zauri, R.; Berni, N.; Brocca, L.; Moramarco, T.; Salciarini, D.; Tamagnini, C.

    2012-04-01

    The early warning systems dedicated to landslides and floods represent the Umbria Region Civil Protection Service new generation tools for hydraulic and hydrogeological risk reduction. Following past analyses performed by the Functional Centre (part of the civil protection service dedicated to the monitoring and the evaluation of natural hazards) on the relationship between saturated soil conditions and rainfall thresholds, we have developed an automated early warning system for the landslide risk, called LANDWARN, which generates daily and 72h forecast risk matrix with a dense mesh of 100 x 100m, throughout the region. The system is based on: (a) the 20 days -observed and 72h -predicted rainfall, provided by the local meteorological network and the Local scale Meteorological Model COSMO ME, (b) the assessment of the saturation of soils by: daily extraction of ASCAT satellite data, data from a network of 16 TDR sensors, and a water balance model (developed by the Research Institute for Geo-Hydrological Protection, CNR, Perugia, Italy) that allows for the prediction of a saturation index for each point of the analysis grid up to a window of 72 h, (c) a Web-GIS platform that combines the data grids of calculated hazard indicators with layers of landslide susceptibility and vulnerability of the territory, in order to produce dynamic risk scenarios. The system is still under development and it's implemented at different scales: the entire region, and a set of known high-risk landslides in Umbria. The system is monitored and regularly reviewed through the back analysis of landslide reports for which the activation date is available. Up to now, the development of the system involves: a) the improvement of the reliability assessment of the condition of soil saturation, a key parameter which is used to dynamically adjust the values of rainfall thresholds used for the declaration of levels of landslide hazard. For this purpose, a procedure was created for the ASCAT satellite data daily download, used for the derivation of a soil water content index (SWI): these data are compared with instrumental ones from the TDR stations and the results of the water balance model that evaluates the contributions of water infiltration, percolation, evapotranspiration, etc. using physically based parameters obtained through a long process of characterization of soil and rock types, for each grid point; b) The assessment of the contribution due to the melting of the snow; c) the physically based - coupling model slope stability analysis, GIS-based, developed by the Department of Civil and Environmental Engineering, University of Perugia, with the aim to introduce also the actual mechanical and physical characteristics of slopes in the analysis. As result of the system, is the daily creation of near real-time and 24, 48, 72h forecast risk scenarios, that, under the intention of the Department of Civil Protection Service, will be used by the Functional Centre for the institutional tasks of hydrogeological risk evaluation and management, but also by local Administrations involved in the monitoring and assessment of landslide risk, in order to receive feedback on the effectiveness of the scenarios produced.

  17. The water cycle in a bottle: simulation of a hydrogeological basin

    NASA Astrophysics Data System (ADS)

    Nebot Castelló, M. R.; Leiva Hevia, S.

    2012-04-01

    THE WATER CYCLE IN A BOTTLE: simulation of a hydrogeological basin Author: Mª Roser Nebot (Institut Manuel Blancafort, La Garriga, Barcelona, Spain) Co-author: Sílvia Leiva Hevia (Institut Llicà d'Amunt, Lliça d'Amunt, Barcelona, Spain) The activity can be implemented in a great range of ages, because it has many different levels of depth. It is based on the construction of an analogical model of a hydrogeological basin using a 5L or 8L empty bottle. There are also other hands-on experiences that can be done in relation to the central one, such as creating a fountain, making a cloud, fog, a breeze… The use of a model that the students have to build and interact with enhances the possibility of cooperative and dialogic learning. The set of activities begins with an introduction to see what the students know about the water cycle and to focus on what they are going to work on. It also makes them think about underground water, which is frequently forgotten when drawing and studying the water cycle. Then, the building of the water cycle simulation from an empty bottle is presented, see http://www.xtec.cat/cirel/pla_le/nottingham/roser_nebot/index.htm (Unit 5). You will also find other activities related to the water cycle at the site. The students build the model, water the soil, and observe infiltration and the formation of a lake. Using a syringe they overexploit the well and dry the lake. By making the students label the underground water level and observe how water percolates through the holes in the aquifer we are making them aware that underground water doesn't circulate in rivers inside underground tunnels, but through the interconnected holes and crevices. Inside the bottle there is a little plant to observe evapotranspiration but, because it is very difficult to see the water droplets in the small plant that is inside the set-up, it is advisable to do a parallel experiment using bigger plants in a pot, covering them with a plastic bag tied around the stem, with the soil exposed to air, leaving some of them in the shade and some in the sun. The origin of condensation is thoroughly discussed so that the students understand that evapotranspiration comes from the addition of transpiration (plants) to evaporation. The students also add colouring to simulate contamination and salt to simulate marine intrusion. These activities, together with the overexploitation, help to understand how humans affect nature and how the effects are not the same in different parts of the world. To finish, there are different exercises to review, summarize and complement all that has been learnt through the lesson. To acknowledge the fact that many times underground water is forgotten, as homework they have to surf the net to see the many water cycle drawings and animations that don't show the water in the aquifers, and sometimes when the water is seen, the rocks that contain it are not depicted. They are also encouraged to realize that in water cycle representations, it never rains over the sea and that to adjust to what really happens and that there should also be rain over the oceans and seas. To finish, the idea that within the water cycle model there are many interrelated processes is discussed

  18. Conceptual hydrogeologic framework of the shallow aquifer system at Virginia Beach, Virginia

    USGS Publications Warehouse

    Smith, Barry S.; Harlow,, George E., Jr.

    2002-01-01

    The hydrogeologic framework of the shallow aquifer system at Virginia Beach was revised to provide a better understanding of the distribution of fresh ground water, its potential use, and its susceptibility to contamination. The revised conceptual framework is based primarily on analyses of continuous cores and downhole geophysical logs collected at 7 sites to depths of approximately 200 ft.The shallow aquifer system at Virginia Beach is composed of the Columbia aquifer, the Yorktown confining unit, and the Yorktown-East-over aquifer. The shallow aquifer system is separated from deeper units by the continuous St. Marys confining unit.The Columbia aquifer is defined as the predominantly sandy surficial deposits above the Yorktown confining unit. The Yorktown confining unit is composed of a series of very fine sandy to silty clay units of various colors at or near the top of the Yorktown Formation. The Yorktown confining unit varies in thickness and in composition, but on a regional scale is a leaky confining unit. The Yorktown-Eastover aquifer is defined as the predominantly sandy deposits of the Yorktown Formation and the upper part of the Eastover Formation above the confining clays of the St. Marys Formation. The limited areal extent of highly permeable deposits containing freshwater in the Yorktown-Eastover aquifer precludes the installation of highly productive freshwater wells over most of the city. Some deposits of biofragmental sand or shell hashes in the Yorktown-Eastover aquifer can support high-capacity wells.A water sample was collected from each of 10 wells installed at 5 of the 7 core sites to determine the basic chemistry of the aquifer system. One shallow well and one deep well was installed at each site. Concentrations of chloride were higher in the water from the deeper well at each site. Concentrations of dissolved iron in all of the water samples were higher than the U.S. Environmental Protection Agency Secondary Drinking Water Regulations. Concentrations of manganese and chloride were higher than the Secondary Drinking Water Regulations in samples from some wells.In the humid climate of Virginia Beach, the periodic recharge of freshwater through the sand units of the shallow aquifer system occurs often enough to create a dynamic equilibrium whereby freshwater flows continually down and away from the center of the ridges to mix with and sweep brackish water and saltwater back toward the tidal rivers, bays, salt marshes, and the Atlantic Ocean.The aquifers and confining units of the shallow aquifer system at Virginia Beach are heterogeneous, discontinuous, and without exact marker beds, which makes correlations in the study area difficult. Investigations using well cuttings, spot cores, or split-spoon samples with geophysical logs are not as definitive as continuous cores for determining or correlating hydrogeologic units. Future investigations of the shallow aquifer system would benefit by collecting continuous cores.

  19. Fractured-aquifer hydrogeology from geophysical logs: Brunswick group and Lockatong Formation, Pennsylvania

    USGS Publications Warehouse

    Morin, R.H.; Senior, L.A.; Decker, E.R.

    2000-01-01

    The Brunswick Group and the underlying Lockatong Formation are composed of lithified Mesozoic sediments that constitute part of the Newark Basin in southeastern Pennsylvania. These fractured rocks form an important regional aquifer that consists of gradational sequences of shale, siltstone, and sandstone, with fluid transport occurring primarily in fractures. An extensive suite of geophysical logs was obtained in seven wells located at the borough of Lansdale, Pennsylvania, in order to better characterize the areal hydrogeologic system and provide guidelines for the refinement of numerical ground water models. Six of the seven wells are approximately 120 m deep and the seventh extends to a depth of 335 m. Temperature, fluid conductivity, and flowmeter logs are used to locate zones of fluid exchange and to quantify transmissivities. Electrical resistivity and natural gamma logs together yield detailed stratigraphic information, and digital acoustic televiewer data provide magnetically oriented images of the borehole wall from which almost 900 fractures are identified. Analyses of the geophysical data indicate that the aquifer penetrated by the deep well can be separated into two distinct structural domains, which may, in turn, reflect different mechanical responses to basin extension by different sedimentary units: 1. In the shallow zone (above 125 m), the dominant fracture population consists of gently dipping bedding plane partings that strike N46??E and dip to the northwest at about 11 degrees. Fluid flow is concentrated in the upper 80 m along these subhorizontal fractures, with transmissivities rapidly diminishing in magnitude with depth. 2. The zone below 125 m marks the appearance of numerous high-angle fractures that are orthogonal to the bedding planes, striking parallel but dipping steeply southeast at 77 degrees. This secondary set of fractures is associated with a fairly thick (approximately 60 m) high-resistivity, low-transmissivity sandstone unit that is abruptly terminated by a thin shale bed at a depth of 190 m. This lower contact effectively delineates the aquifer's vertical extent at this location because no detectable evidence of ground water movement is found below it. Thus, fluid flow is controlled by fractures, but fracture type and orientation are related to lithology. Finally, a transient thermal-conduction model is successfully applied to simulate observed temperature logs, thereby confirming the effects of ground-surface warming that occurred in the area as a result of urbanization at the turn of the century. The systematic warming of the upper 120 m has increased the transmissivity of this aquifer by almost 10%, simply due to changes in fluid viscosity and density.An extensive suite of geophysical logs was obtained in seven wells located at the borough of Landsdale, Pennsylvania, to better characterize the areal hydrogeologic system and provide guidelines for the refinement of numerical ground water models. Temperature, fluid conductivity, and flowmeter logs were used to locate zones of fluid exchange and to quantify transmissivities. Electrical resistivity and natural gamma logs together yield detailed stratigraphic information, and digital acoustic televiewer data provide magnetically oriented images of the borehole wall from which almost 900 fractures are identified.

  20. Ground water flow in a fractured carbonate aquifer inferred from combined hydrogeological and geochemical measurements

    SciTech Connect

    Zanini, L.; Novakowski, K.S.; Lapcevic, P.; Bickerton, G.S.; Voralek, J.; Talbot, C.

    2000-06-01

    A conceptual model for ground water flow is presented for a fractured Silurian dolomite in the Niagara Escarpment area of southern Ontario. Such a model is necessary to facilitate remedial efforts of a PCB-contaminated site located in Smithville, Ontario. Both physical and chemical hydrogeological observations obtained from field investigations were used to deduce the structure of the ground water flow system in the fracture network. The field study was conducted using observations obtained from six bore-holes drilled in the vicinity of the town of Smithville. The boreholes were diamond cored through the entire thickness of the dolomite formation (approximately 45 m), hydraulically tested using a 2 m packer spacing and then completed using multipacker casing strings. Measurements of hydraulic head were obtained on a weekly basis over a period of two years, and ground water from each borehole interval was collected for geochemical analyses for inorganic and isotopic composition. Transmissivity measurements indicate that the dolomite is divided into two ground water flow systems separated by an extensive unit of low transmissivity that is pervasive throughout the region. The upper flow system is characterized by water enriched in Mg{sup 2+} and SO{sub 4}{sup 2{minus}}. Below the low transmissivity zone, ground water increases in salinity and is enriched in Ca{sup 2+} and SO{sub 4}{sup 2{minus}}. Based on the geochemistry, the rate of ground water migration in the lower flow system is surmised to be much less than that in the upper system. Measurements of hydraulic head in conjunction with the results of the analyses of the environmental isotopes ({delta}{sup 18}O and {delta}{sup 2}H) suggest that ground water flow is mainly horizontal and likely governed by enlarged bedding plane fractures. These isotope geochemistry and topographical features further suggest that ground water recharge is occurring approximately 2 km to the north of Smithville.

  1. Hydrogeologic characterization of a proposed landfill expansion in Pickens County near Easley, South Carolina

    USGS Publications Warehouse

    Stringfield, W.J.

    1994-01-01

    This report presents the results of a hydrogeologic study in the Piedmont physiographic province of South Carolina to obtain geologic, hydrologic, and water-quality data from the site of a proposed landfill expansion in Pickens County near Easley, South Carolina. The geology of the study area is typical of the Piedmont region. The unconsolidated regolith on the site is soil and saprolite, which is a product of the weathered parent rock. The soil ranges in thickness from about 5 to 20 feet. The saprolite ranges in thickness from about 5 to 134 feet. The most abundant parent rock type in the area is a biotite gneiss. Ground- and surface-water data were collected at the site. Slug tests on the saprolite indicate a mean hydraulic conductivity of 3 x 0.000003 feet per second. Transmissivity ranges from 12 to 27 cubic feet per day per feet (squared per day). The ground-water velocity for the site ranges from 3 to 6 feet per year. The closest major stream to the site is Golden Creek. Based on low-flow data for Golden Creek, the estimated minimum 7 consecutive day flow that has a recurrence interval of 10 years (7Q10) at station 02186102 is 2.4 cubic feet per second. Water samples were collected from five monitoring wells at the proposed landfill expansion site and from one stream adjacent to the expansion site. Measured pH units ranged from 5.5 to 8.1, and alkalinity concentrations ranged from 5.1 to 73 milligrams per liter as CaCO3. Other water- quality data obtained included temperature and specific conductance, and 5-day BOD (biochemical oxygen demand), bicarbonate, ammonia-nitrogen, nitrite-nitrogen, nitrite plus nitrate, organic carbon, calcium, magnesium, sodium, potassium, chloride, sulfate, fluoride, and selected trace metal concentrations.

  2. Hydrogeologic Assessment of the East Bear Creek Unit, San LuisNational Wildlife Refuge

    SciTech Connect

    Quinn, Nigel W.T.

    2007-07-15

    San Luis National Wildlife Refuge Complex to meetReclamation s obligations for Level 4 water supply under the CentralValley Project Improvement Act. Hydrogeological assessment of the EastBear Creek Unit of the San Luis National Wildlife Refuge was conductedusing a combination of field investigations and a survey of availableliterature from past US Geological Survey Reports and reports by localgeological consultants. Conservative safe yield estimates made using theavailable data show that the East Bear Creek Unit may have sufficientgroundwater resources in the shallow groundwater aquifer to meet aboutbetween 25 percent and 52 percent of its current Level II and between 17percent and 35 percent of its level IV water supply needs. The rate ofsurface and lateral recharge to the Unit and the design of the well fieldand the layout and capacity of pumped wells will decide both thepercentage of annual needs that the shallow aquifer can supply andwhether this yield is sustainable without affecting long-term aquiferquality. In order to further investigate the merits of pumping the nearsurface aquifer, which appears to have reasonable water quality for usewithin the East Bear Creek Unit -- monitoring of the potential sources ofaquifer recharge and the installation of a pilot shallow well would bewarranted. Simple monitoring stations could be installed both upstreamand downstream of both the San Joaquin River and Bear Creek and beinstrumented to measureriver stage, flow and electrical conductivity.Ideally this would be done in conjunction with a shallow pilot well,pumped to supply a portion of the Unit's needs for the wetland inundationperiod.

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

    SciTech Connect

    Spane, F.A. Jr.; Webber, W.D.

    1995-09-01

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

  4. Hydrogeology and effects of tailings basins on the hydrology of Sands Plain, Marquette County, Michigan

    USGS Publications Warehouse

    Grannemann, N.G.

    1984-01-01

    A hydrogeological study of Sands Plain, a sandy outwash area in the north-central part of Michigan 's Upper Peninsula, was conducted during 1979-82. Parts of the area are being considered as possible sites for construction and operation of iron mining tailings basins. Gribben Basin, an existing tailings basin in the western part of Sands Plains, covers 2.5 square miles; hypothetical tailings basins may cover as much as 11 square miles. Glacial deposits are the area 's principal aquifer. The general direction of ground-water flow is from the outwash area toward Lake Superior. Before reaching Lake Superior, however, most ground water is discharged in a series of nearly parallel streams. Ground water accounts for 95 percent of the discharge of these streams. Precipitation collected at two sites had average pH values of 4.0. Dissolved solids concentrations in water from wells ranged from 41 to 246 milligrams per liter; in water from streams, they ranged from 82 to 143 milligrams per liter. Calcium and bicarbonate were the principal dissolved ions. A two-dimensional digital model of ground-water flow was used to simulate ground-water levels and runoff. The predictive computer simulations indicate that construction and operation of Gribben tailings basin, located in the western part of the study area, decreased ground-water flow to Goose Lake Outlet by 0.9 to 1.6 cubic feet per second. Construction and operation of four hypothetical tailings basins covering a total of 11 square miles is estimated to reduce ground-water flow to the area 's streams by 7 to 18 cubic feet per second depending on the hydraulic properties of material comprising the basin boundaries. Leakage from all of the basins is estimated to range from 0.7 to 7 cubic feet per second. (USGS)

  5. Hydrogeologic factors affecting cavern morphology within rocks of Mississippian age in northwestern Arkansas

    SciTech Connect

    Fanning, B.J. . Dept. of Geology); Brahana, J.V. . Geological Survey)

    1993-02-01

    Cavern development within rocks of Mississippian age in northwestern Arkansas is associated with two Pleistocene erosional features, the Boston Mountains Plateau and the Springfield Plateau. Each plateau is characterized by a distinct stratigraphic sequence with unique lithologies. Cavern morphology (both cross-sectional and planimetric) in each plateau is the result of the complex interaction of numerous hydrogeologic factors. Four of the most dominant factors which affect cavern morphology appear to be: (1) composition and continuity of the confining units; (2) percentage of noncarbonate components in rocks of the cavern-forming interval; (3) nature and distribution of ground-water recharge to the cavern-forming interval; and (4) nature and distribution of fractures within the cavern-forming interval. Network maze patterns typically develop in the Pitkin Limestone, the formation in which most caverns form beneath the Boston Mountains Plateau. The Pitkin, a bioclastic limestone, is confined above by siltstones of the Cane Hill member of the Hale Formation and below by shales of the Fayetteville Formation. The maze pattern indicates that these caverns probably were formed by dissolution of the rock matrix by diffuse recharge moving vertically through leaky confining units. Single rooms are the dominant cavern morphology in the chert-dominated Boone Formation of the Springfield Plateau. Where the concentration of chert is greater than 50 percent, the Boone lacks structural integrity and fails to develop well-integrated conduit networks. Point recharge features in outcrop areas of the Boone Formation are not visible in most of the Springfield Plateau because the insoluble residuum masks the upper bedrock surface. Where the Boone Formation is less than 7 meters thick, surface karst features are more prevalent.

  6. Correlation of Miocene sequences and hydrogeologic units, New Jersey Coastal Plain

    USGS Publications Warehouse

    Sugarman, P.J.; Miller, K.G.

    1997-01-01

    We have developed a Miocene sequence stratigraphic framework using data from recently drilled boreholes in the New Jersey Coastal Plain. Sequences are shallowing upward, unconformity-bounded units; fine-grained shelf and prodelta sediments grade upward to delta front and shallow-marine sands, corresponding to confining bed-aquifer couplets. By dating Miocene sequences using Sr-isotope stratigraphy, and mapping with borehole data and geophysical logs, we can predict the continuity and effectiveness of the confining beds and aquifers. The following are illustrated on a 90-km basinward dip section: (1) the composite confining bed is comprised of the KwO and lower Kw1a (ca. 23.8-20.5 Ma) sequences downdip at Atlantic City, and the Kw1b, Kw1a and older sequences updip (ca. 69.3-20.6 Ma), and is continuous throughout most of the coastal plain; (2) the major confined aquifer, the Atlantic City 800-foot sand, is comprised of the upper Kw1a and Kw1b sequences (ca. 20.5-20.2 Ma) and is an areally continuous sand that is interconnected with the Kirkwood-Cohansey aquifer system updip of Mays Landing; (3) the confining bed above the Atlantic City 800-foot sand is comprised of the Kw2a, Kw2b, and Kw3 sequences (18.1-13.3 Ma) and is an extensive confining bed that pinches out updip. These sequences and aquifer-confining bed couplets are linked to global sea-level changes evinced by the ??18O record. We conclude that sequence stratigraphy is a powerful tool when applied to regional hydrogeologic problems, although basinal tectonic differences and localized variations in sediment supply can affect aquifer thickness and permeability.

  7. Comprehensive principles of quantitative hydrogeology established by Darcy (1856) and Dupuit (1857)

    NASA Astrophysics Data System (ADS)

    Ritzi, Robert W.; Bobeck, Patricia

    2008-10-01

    Henry Darcy and Jules Dupuit were born 1 year apart, were classmates during their undergraduate and graduate education in civil engineering, and were colleagues in the French corps of civil engineers, with overlapping appointments as inspector general in the early 1850s. At that time Darcy turned over, to Dupuit, his position as Director of Water and Bridges in Paris and the research on pipe flow he had begun there in 1849. In these pipe flow experiments, Darcy discovered what he referred to as a "law" of fluid mechanics, which is that above a certain velocity threshold, the head loss is proportional to velocity squared, and below that threshold, the head loss is linearly proportional to velocity. During the remainder of their careers, Darcy and Dupuit applied this law with their collective, extensive, prior knowledge of fluid mechanics, geology, aquifers, wells, and springs to quantitative studies of fluid flow in the subsurface (and also in pipes, aqueducts, rivers, and sand filters). Two monographs by Darcy (1856) and Dupuit (1857) are mutually cited retrospectives on much of this research, submitted at nearly the same time, to the same Corps des Ponts et Chaussées publisher, near the end of their careers. Between these two monographs, many of the fundamentals of quantitative hydrogeology were established, including the equation for groundwater motion, average linear velocity, average travel time, effective hydraulic conductivity for layered heterogeneity, conservation of mass in confined and unconfined flow, the nature of the regional pieziometric surface, porous flow versus flow through discrete fractures and karst conduits, the equation for a cone of depression around flowing wells, superposition of the effects of multiple wells, and capture zone geometries of wells within a regional flow field.

  8. Groundwater protection and unconventional gas extraction: the critical need for field-based hydrogeological research.

    PubMed

    Jackson, R E; Gorody, A W; Mayer, B; Roy, J W; Ryan, M C; Van Stempvoort, D R

    2013-01-01

    Unconventional natural gas extraction from tight sandstones, shales, and some coal-beds is typically accomplished by horizontal drilling and hydraulic fracturing that is necessary for economic development of these new hydrocarbon resources. Concerns have been raised regarding the potential for contamination of shallow groundwater by stray gases, formation waters, and fracturing chemicals associated with unconventional gas exploration. A lack of sound scientific hydrogeological field observations and a scarcity of published peer-reviewed articles on the effects of both conventional and unconventional oil and gas activities on shallow groundwater make it difficult to address these issues. Here, we discuss several case studies related to both conventional and unconventional oil and gas activities illustrating how under some circumstances stray or fugitive gas from deep gas-rich formations has migrated from the subsurface into shallow aquifers and how it has affected groundwater quality. Examples include impacts of uncemented well annuli in areas of historic drilling operations, effects related to poor cement bonding in both new and old hydrocarbon wells, and ineffective cementing practices. We also summarize studies describing how structural features influence the role of natural and induced fractures as contaminant fluid migration pathways. On the basis of these studies, we identify two areas where field-focused research is urgently needed to fill current science gaps related to unconventional gas extraction: (1) baseline geochemical mapping (with time series sampling from a sufficient network of groundwater monitoring wells) and (2) field testing of potential mechanisms and pathways by which hydrocarbon gases, reservoir fluids, and fracturing chemicals might potentially invade and contaminate useable groundwater. PMID:23745972

  9. Episodic origin of a large outwash complex during multiple glaciations -- Geologic and hydrogeologic implications

    SciTech Connect

    Brown, S.E.; Fleming, A.H. )

    1994-04-01

    The White River valley in Marion County is underlain by a massive outwash complex that constitutes the most productive aquifer in the greater Indianapolis area, and an understanding of its geologic evolution is essential to the proper development and protection of the resource. Subsurface studies indicate that this part of the valley functioned as a major meltwater conduit for glacial episodes that took place at times ranging from pre-Illinoian to late Wisconsin. Consequently, surficial outwash associated with the latest Wisconsin ice sheet appears to be of limited volumetric importance in many parts of the valley. Instead, the bulk of the complex consists of several distinct depositional sequences that exhibit a variety of cross-cutting and inset relations, and which are at places separated by prominent paleosurfaces. Each sequence typically consists of outwash fans and(or) meltwater channels that are broadly symmetric about the modern valley, or that parallel buried bedrock valleys that underlie some segments of the modern valley. The striking similarities between sequences of such vastly different ages suggest that they result from a basic depositional pattern that repeated over the course of successive glaciations. It seems likely that bedrock topography, particularly the Knobstone Escarpment that lies just west of the modern valley, was the ultimate control on the dynamics of relatively thin ice sheets and thus repeatedly influenced the distributions of meltwater and sedimentary facies in the valley. Recognition of similar depositional patterns through time provides the necessary facies models for many hydrogeologic applications, such as development and protection of public wellfields, investigations of environmental sites, and interpretation of water-quality samples.

  10. Characterization of Physical and Hydro-Geological Properties of Kanamaru Research Site in Japan

    NASA Astrophysics Data System (ADS)

    Takeda, M.; Zhang, M.; Takeno, N.; Watanabe, Y.

    2004-12-01

    Establishing the comprehensive knowledge of applicability of the methods for investigating hydraulic properties of low permeability geologic strata is an urgent issue for supporting regulation of geological disposal of nuclear waste in the near future. As a beginning of this work, a systematic examination of various kinds of techniques for hydro-geological surveys has been started in Kanamaru Research Site in Japan. This paper briefly introduces the research plan and preliminary results obtained from the first year of investigation. The survey techniques include borehole excavation, borehole imaging, gamma-ray, caliper, acoustic, electrical resistivity and density loggings, permeability tests and flow direction measurement using a single borehole, permeability tests and flow direction measurement using multi boreholes, etc. Preliminary findings can be summarized as follows: (1) The stratigraphy at the survey area consists of topsoil, debris sediments, sandstone, mudstone, conglomeratic sandstone, mudstone, arkose sandstone, and granite. High uranium concentrations are detected at lower portion of the conglomeratic sandstone by gamma-ray logging. (2) The survey area is located at a slope inclined from the north to the south, and the dominant groundwater flow is considered to be in the direction form the north to the south. And the downward flow was also recognized by the flow direction measurements and water quality logging. (3) Hydraulic conductivities derived from permeability tests using a single borehole were in the range of 5E-10 to 1E-7 m/s. The hydraulic conductivities of the same lithology derived from different boreholes varied, and the discrepancies were up to an order. This result indicates that the formations in the survey area have hydraulic heterogeneity in both the vertical and horizontal directions. (4) On the whole, stratum with fast velocity of elastic wave showed large resistivity and low permeability. The degree of correlation between the hydraulic and physical properties was different for each stratum.

  11. Data requirements for simulation of hydrogeologic effects of liquid waste injection, Harrison and Jackson Counties, Mississippi

    USGS Publications Warehouse

    Rebich, Richard A.

    1994-01-01

    Available literature and data were reviewed to quantify data requirements for computer simulation of hydrogeologic effects of liquid waste injection in southeastern Mississippi. Emphasis of each review was placed on quantifying physical properties of current Class I injection zones in Harrison and Jackson Counties. Class I injection zones are zones that are used for injection of hazardous or non-hazardous liquid waste below a formation containing the lowermost underground source of drinking water located within one-quarter of a mile of the injection well. Several mathematical models have been developed to simulate injection effects. The Basic Plume Method was selected because it is commonly used in permit applications, and the Intercomp model was selected because it is generally accepted and used in injection-related research. The input data requirements of the two models were combined into a single data requirement list inclusive of physical properties of injection zones only; injected waste and well properties are not included because such information is site-specific by industry, which is beyond the scope of this report. Results of the reviews of available literature and data indicated that Class I permit applications and standard-reference chemistry and physics texts were the primary sources of information to quantify physical properties of injection zones in Harrison and Jackson Counties. With the exception of a few reports and supplementary data for one injection zone in Jackson County, very little additional information pertaining to physical properties of the injection zones was available in sources other than permit applications and standard-reference texts.

  12. Hydrogeologic framework of the Deccan terrain of the Koyna River basin, India

    NASA Astrophysics Data System (ADS)

    Naik, Pradeep K.; Awasthi, Arun K.; Anand, A.; Mohan, Prakash C.

    2001-06-01

    The Koyna River basin in India drew the attention of geoscientists after an earthquake (magnitude 7) in 1967. Since then, detailed geological, tectonic, and seismic investigations of this river basin have been carried out by several workers. However, very little study has been done on its hydrogeological framework. The present work aims at filling this gap. Basalts, laterites, alluvium, soils, and talus deposits form shallow unconfined aquifers, with transmissivity of 27-135 m2/d and a regional specific yield of 0.012. In shallow basaltic aquifers, the lower part of the highly weathered and highly jointed horizon above, and the poorly weathered and highly jointed horizon below, form the most potential zone for groundwater occurrence. Well yields in the deeper basaltic aquifers are directly related to the occurrence of lineaments, whereas at a shallower level they are related to geomorphic features. Spring discharges are highly dependent on their source aquifers and areas of recharge. They have a mean winter discharge of 46 m3/d and a summer discharge of 28 m3/d. Chemically, groundwaters are dominated by alkaline earths (Ca2+, Mg2+) and weak acids (HCO3 -, CO3 -); they are calcium-bicarbonate type (53%) and calcium-magnesium-bicarbonate type (27%) at shallower levels; and calcium-magnesium-bicarbonate type (29%), sodium-bicarbonate type (24%), calcium-bicarbonate type (19%), and calcium-magnesium-sodium-bicarbonate type (19%) in deeper aquifers. The Koyna River basin is characterized by both scarcity and abundance of groundwater. In the water-scarce areas in the dissected plateaus, artificial recharge of aquifers through construction of several recharge structures at suitable locations is highly recommended. In the water-abundant areas in the central valley, on the other hand, expanded consumptive use of water resources is encouraged.

  13. Hydrogeologic Controls on Water Dynamics in a Discontinuous Permafrost, Lake-Rich Landscape

    NASA Astrophysics Data System (ADS)

    Walvoord, M. A.; Briggs, M. A.; Day-Lewis, F. D.; Jepsen, S. M.; Lane, J. W., Jr.; McKenzie, J. M.; Minsley, B. J.; Striegl, R. G.; Voss, C. I.; Wellman, T. P.

    2014-12-01

    Understanding permafrost distribution, rate of change, and influence on groundwater movement are critical for assessing climate change impacts in northern ecosystems. Lake-rich lowlands in interior Alaska provide important habitat for migratory waterfowl, ungulates, and other wildlife. Despite low annual precipitation, the Yukon Flats area in the north central Yukon River Basin of Alaska (USA) supports over 20,000 lakes, due in part to the presence of permafrost. The fate of this lake-rich lowland and, by proxy, similar circumboreal lowland systems under projected climate warming is the focus of a series of recent studies highlighted here. Lake water chemistry analyses of over 200 lakes in the Yukon Flats reveal a large degree of spatial heterogeneity suggestive of a hydrologically disconnected system, a conclusion also supported by abrupt spatial changes in lake elevation. Airborne geophysical characterization shows a laterally continuous shallow gravel layer (~25-m thick) that would offer good hydraulic connectivity throughout the lowlands. However, the gravel layer is generally frozen (as permafrost) except beneath surface water bodies; thus inhibiting lateral pathways of groundwater flow under current conditions. Ground-based geophysical characterization provides a high resolution of permafrost distribution and relevant hydrogeologic features at several lake study sites. Relatively recent thaw in the gravel layer appears to be associated with lakes that have experienced change in size (area) over the past several decades, whereas lakes with taliks (unfrozen conduits) that fully penetrate the permafrost layer are more likely to be stable. Multi-scale permafrost characterization provides the basis for numerical models that simulate permafrost dynamics, lake-talik evolution, supra-, intra-, and sub-permafrost groundwater flow, lake-groundwater exchange, active layer dynamics, and permafrost aggradation response to lake recession. Collective field and simulation results provide insight into expected alterations in groundwater flowpaths, water budgets, lake distribution, and lake chemistry in discontinuous permafrost lowlands given continued climate and permafrost change.

  14. Hydrogeologic controls on nitrate transport in a small agricultural catchment, Iowa

    USGS Publications Warehouse

    Schilling, K.E.; Tomer, M.D.; Zhang, Y.-K.; Weisbrod, T.; Jacobson, P.; Cambardella, C.A.

    2007-01-01

    Effects of subsurface deposits on nitrate loss in stream riparian zones are recognized, but little attention has been focused on similar processes occurring in upland agricultural settings. In this paper, we evaluated hydrogeologic controls on nitrate transport processes occurring in a small 7.6 ha Iowa catchment. Subsurface deposits in the catchment consisted of upland areas of loess overlying weathered pre-Illinoian till, drained by two ephemeral drainageways that consisted of Holocene-age silty and organic rich alluvium. Water tables in upland areas fluctuated more than 4 m per year compared to less than 0.3 m in the drainageway. Water quality patterns showed a distinct spatial pattern, with groundwater in the drainageways having lower nitrate concentrations (10 mg L-1) as wells as lower pH, dissolved oxygen and redox, and higher ammonium and dissolved organic carbon levels. Several lines of evidence suggested that conditions are conducive for denitrification of groundwater flowing from uplands through the drainageways. Field-measured nitrate decay rates in the drainageways (???0.02 day-1) were consistent with other laboratory studies and regional patterns. Results from MODFLOW and MT3DMS simulations indicated that soils in the ephemeral drainageways could process all upland groundwater nitrate flowing through them. However, model-simulated tile drainage increased both water flux and nitrate loss from the upland catchment. Study results suggest that ephemeral drainageways can provide a natural nitrate treatment system in our upland glaciated catchments, offering management opportunities to reduce nitrate delivery to streams. Copyright 2007 by the American Geophysical Union.

  15. Faulting and groundwater in a desert environment: constraining hydrogeology using time-domain electromagnetic data

    USGS Publications Warehouse

    Bedrosian, Paul A.; Burgess, Matthew K.; Nishikawa, Tracy

    2013-01-01

    Within the south-western Mojave Desert, the Joshua Basin Water District is considering applying imported water into infiltration ponds in the Joshua Tree groundwater sub-basin in an attempt to artificially recharge the underlying aquifer. Scarce subsurface hydrogeological data are available near the proposed recharge site; therefore, time-domain electromagnetic (TDEM) data were collected and analysed to characterize the subsurface. TDEM soundings were acquired to estimate the depth to water on either side of the Pinto Mountain Fault, a major east-west trending strike-slip fault that transects the proposed recharge site. While TDEM is a standard technique for groundwater investigations, special care must be taken when acquiring and interpreting TDEM data in a twodimensional (2D) faulted environment. A subset of the TDEM data consistent with a layered-earth interpretation was identified through a combination of three-dimensional (3D) forward modelling and diffusion time-distance estimates. Inverse modelling indicates an offset in water table elevation of nearly 40 m across the fault. These findings imply that the fault acts as a low-permeability barrier to groundwater flow in the vicinity of the proposed recharge site. Existing production wells on the south side of the fault, together with a thick unsaturated zone and permeable near-surface deposits, suggest the southern half of the study area is suitable for artificial recharge. These results illustrate the effectiveness of targeted TDEM in support of hydrological studies in a heavily faulted desert environment where data are scarce and the cost of obtaining these data by conventional drilling techniques is prohibitive.

  16. Hydrogeology of the Beaver Kill basin in Sullivan, Delaware, and Ulster Counties, New York

    USGS Publications Warehouse

    Reynolds, Richard J.

    2000-01-01

    The hydrogeology of the 299-square-mile Beaver Kill basin in the southwestern Catskill Mountains of southeastern New York is depicted in a surficial geologic map and five geologic sections, and is summarized through an analysis of low-flow statistics for the Beaver Kill and its major tributary, Willowemoc Creek. Surficial geologic data indicate that the most widespread geologic units within the basin are ablation and lodgment till. Large masses of ablation till as much as 450 feet thick were deposited as lateral embankments within the narrow Beaver Kill and Willowemoc Creek valleys and have displaced the modern stream courses by as much as 1,000 feet from the preglacial bedrock-valley axis. Low-flow statistics for the Beaver Kill and Willowemoc Creeks indicate that the base flows (discharges that are exceeded 90 percent of the time) of these two streams--0.36 and 0.39 cubic feet per square mile,respectively--are the highest of 13 Catskill Mountain streams studied. High base flows elsewhere in the glaciated northeastern United States are generally associated with large stratified-drift aquifers, however, stratified drift in these two basins accounts for only about 5 percent and 4.4 percent of their respective surface areas, respectively. The high base flows in these two basins appear to correlate with an equally high percentage of massive sandstone members of the Catskill Formation, which underlies the entire region. Ground-water seepage from these sandstone members may be responsible for the high base flows of these two streams.

  17. Improving hydrogeological models of deltaic sedimentary media using GIS based 3D geological tools

    NASA Astrophysics Data System (ADS)

    Velasco, V.; Gogu, R.; Vázquez-Suñé, E.; Monfort, D.; Garriga, A.; Carrera, J.

    2009-04-01

    Due to the natural heterogeneity the hydrological modeling in the deltaic sedimentary media is complex. Reliable 3D hydrogeological models could be created by integrating properly detailed and accurate data. This data has to be properly managed and interpreted. The first task has been the creation of a geospatial database to store and to allow the management of a great amount of different data types coming from different sources (geophysical, geological, hydraulic, and others). The data structure allows storing an accurate and very detailed core geological description that can be straightforwardly generalized and further upscaled. The second step was to create tools within a GIS environment allowing querying and visualizing the data. One consists in illustrating the core with the detailed geological description of each selected borehole. Another creates geologic profiles by using an on screen defined buffer zone selection for the needed boreholes. The lithological columns of the boreholes together with the defined stratigraphic subunits appear on screen as a geological profile. Complementary information like the DTM profile, the distance between the boreholes, the depth of each strata complete the geological picture. In this working environment the user is able to analyze the possible existing stratigraphical units and to define them on screen in a deterministic way or by using geostatistics. Additionally information like the type of the contact surface, the position between the geological units or subunits as well as other parameters could be attached as attributes. The possible faults or fractures can be identified within the same environment. To date, a dictionary of terms describing the possible geological contact surfaces types is on the way to be defined. In parallel, a tool of converting the geological units/subunits analyzed data is developed in order to project the obtained information within a 3D environment. The export procedure provides a spatial located points mass with their attached attributes. The points mass could be used within the same GIS environment or by external software packages to derive a reliable 3D model.

  18. Automatic Multi-Scale Calibration Procedure for Nested Hydrological-Hydrogeological Regional Models

    NASA Astrophysics Data System (ADS)

    Labarthe, B.; Abasq, L.; Flipo, N.; de Fouquet, C. D.

    2014-12-01

    Large hydrosystem modelling and understanding is a complex process depending on regional and local processes. A nested interface concept has been implemented in the hydrosystem modelling platform for a large alluvial plain model (300 km2) part of a 11000 km2 multi-layer aquifer system, included in the Seine basin (65000 km2, France). The platform couples hydrological and hydrogeological processes through four spatially distributed modules (Mass balance, Unsaturated Zone, River and Groundwater). An automatic multi-scale calibration procedure is proposed. Using different data sets from regional scale (117 gauging stations and 183 piezometers over the 65000 km2) to the intermediate scale(dense past piezometric snapshot), it permits the calibration and homogenization of model parameters over scales.The stepwise procedure starts with the optimisation of the water mass balance parameters at regional scale using a conceptual 7 parameters bucket model coupled with the inverse modelling tool PEST. The multi-objective function is derived from river discharges and their de-composition by hydrograph separation. The separation is performed at each gauging station using an automatic procedure based one Chapman filter. Then, the model is run at the regional scale to provide recharge estimate and regional fluxes to the groundwater local model. Another inversion method is then used to determine the local hydrodynamic parameters. This procedure used an initial kriged transmissivity field which is successively updated until the simulated hydraulic head distribution equals a reference one obtained by krigging. Then, the local parameters are upscaled to the regional model by renormalisation procedure.This multi-scale automatic calibration procedure enhances both the local and regional processes representation. Indeed, it permits a better description of local heterogeneities and of the associated processes which are transposed into the regional model, improving the overall performances of the two nested models.

  19. Developing a modular hydrogeology ontology by extending the SWEET upper-level ontologies

    NASA Astrophysics Data System (ADS)

    Tripathi, Ajay; Babaie, Hassan A.

    2008-09-01

    Upper-level ontologies comprise general concepts and properties which need to be extended to include more diverse and specific domain vocabularies. We present the extension of NASA's Semantic Web for Earth and Environmental Terminology (SWEET) ontologies to include part of the hydrogeology domain. We describe a methodology that can be followed by other allied domain experts who intend to adopt the SWEET ontologies in their own discipline. We have maintained the modular design of the SWEET ontologies for maximum extensibility and reusability of our ontology in other fields, to ensure inter-disciplinary knowledge reuse, management, and discovery. The extension of the SWEET ontologies involved identification of the general SWEET concepts (classes) to serve as the super-class of the domain concepts. This was followed by establishing the special inter-relationships between domain concepts (e.g., equivalence for vadose zone and unsaturated zone), and identifying the dependent concepts such as physical properties and units, and their relationship to external concepts. Ontology editing tools such as SWOOP and Protégé were used to analyze and visualize the structure of the existing OWL files. Domain concepts were introduced either as standalone new classes or as subclasses of existing SWEET ontologies. This involved changing the relationships (properties) and/or adding new relationships based on domain theories. In places, in the Owl files, the entire structure of the existing concepts needed to be changed to represent the domain concept more meaningfully. Throughout this process, the orthogonal structure of SWEET ontologies was maintained and the consistency of the concepts was tested using the Racer reasoner. Individuals were added to the new concepts to test the modified ontologies. Our work shows that SWEET ontologies can successfully be extended and reused in any field without losing their modular or reference structure, or disrupting their URI links.

  20. Hydrogeology and Ground-Water Flow in the Opequon Creek Watershed area, Virginia and West Virginia

    USGS Publications Warehouse

    Kozar, Mark D.; Weary, David J.

    2009-01-01

    Due to increasing population and economic development in the northern Shenandoah Valley of Virginia and West Virginia, water availability has become a primary concern for water-resource managers in the region. To address these issues, the U.S. Geological Survey (USGS), in cooperation with the West Virginia Department of Health and Human Services and the West Virginia Department of Environmental Protection, developed a numerical steady-state simulation of ground-water flow for the 1,013-square-kilometer Opequon Creek watershed area. The model was based on data aggregated for several recently completed and ongoing USGS hydrogeologic investigations conducted in Jefferson, Berkeley, and Morgan Counties in West Virginia and Clarke, Frederick, and Warren Counties in Virginia. A previous detailed hydrogeologic assessment of the watershed area of Hopewell Run (tributary to the Opequon Creek), which includes the USGS Leetown Science Center in Jefferson County, West Virginia, provided key understanding of ground-water flow processes in the aquifer. The ground-water flow model developed for the Opequon Creek watershed area is a steady-state, three-layer representation of ground-water flow in the region. The primary objective of the simulation was to develop water budgets for average and drought hydrologic conditions. The simulation results can provide water managers with preliminary estimates on which water-resource decisions may be based. Results of the ground-water flow simulation of the Opequon Creek watershed area indicate that hydrogeologic concepts developed for the Hopewell Run watershed area can be extrapolated to the larger watershed model. Sensitivity analyses conducted as part of the current modeling effort and geographic information system analyses of spring location and yield reveal that thrust and cross-strike faults and low-permeability bedding, which provide structural and lithologic controls, respectively, on ground-water flow, must be incorporated into the model to develop a realistic simulation of ground-water flow in the larger Opequon Creek watershed area. In the model, recharge for average hydrologic conditions was 689 m3/d/km2 (cubic meters per day per square kilometer) over the entire Opequon Creek watershed area. Mean and median measured base flows at the streamflow-gaging station on the Opequon Creek near Martinsburg, West Virginia, were 604,384 and 349,907 m3/d (cubic meters per day), respectively. The simulated base flow of 432,834 m3/d fell between the mean and median measured stream base flows for the station. Simulated base-flow yields for subwatersheds during average conditions ranged from 0 to 2,643 m3/d/km2, and the median for the entire Opequon Creek watershed area was 557 m3/d/km2. A drought was simulated by reducing model recharge by 40 percent, a rate that approximates the recharge during the prolonged 16-month drought that affected the region from November 1998 to February 2000. Mean and median measured streamflows for the Opequon Creek watershed area at the Martinsburg, West Virginia, streamflow-gaging station during the 1999 drought were 341,098 and 216,551 m3/d, respectively. The simulated drought base flow at the station of 252,356 m3/d is within the range of flows measured during the 1999 drought. Recharge was 413 m3/d/km2 over the entire watershed during the simulated drought, and was 388 m3/d/km2 at the gaging station. Simulated base-flow yields for drought conditions ranged from 0 to 1,865 m3/d/km2 and averaged 327 m3/d/km2 over the entire Opequon Creek watershed. Water budgets developed from the simulation results indicate a substantial component of direct ground-water discharge to the Potomac River. This phenomenon had long been suspected but had not been quantified. During average conditions, approximately 564,176 m3/d of base flow discharges to the Potomac River. An additional 124,379 m3/d of ground water is also estimated to discharge directly to the Potomac River and rep

  1. A multidisciplinary approach to define the hydrogeological model of the carbonate aquifer system in the Versilia River basin (Tuscany, Italy)

    NASA Astrophysics Data System (ADS)

    Menichini, M.; Doveri, M.; Giannecchini, R.; Raco, B.; Rosi, M.

    2012-12-01

    A hydrogeological study was carried out on important fractured/karst aquifer systems located in the Versilia River basin (Tuscany, Italy), in order to optimize the groundwater resources management. The main aim was the individuation of the feeding areas of the most important springs by means of a multidisciplinary approach using geological, hydrogeological and geochemical-isotopic tools. Some hydrogeological sections were elaborated in order to define the geometry of the main hydrostructures and to individuate possible groundwater divides. The elaboration of geochemical data allowed at identifying 3 main chemical facies: Ca-HCO3, Ca-SO4 and Na-Cl. The first two highlight the interaction of water with limestone/dolostone and carbonate-evaporite rocks for a time sufficient to acquire these chemical compositions and to achieve saturation/supersaturation in calcite and dolomite. The Na-Cl groundwater shows low salinity and a composition similar to rainwater, indicating a circulation in rocks containing minerals not very reactive and/or short interaction time with carbonate rocks. These two main types of water-rock interaction are confirmed by the isotopic ratio ?13C: for the Ca-HCO3 and Ca-SO4 types, ?13C value requires a significant contribution of carbon derived from dissolution of calcite, while for Na-Cl water, ?13C values are consistent with the addition of biogenic CO2 in rainwater. Stable water isotopes (?18O and ?2H) confirm that groundwaters have a meteoric origin and that the wide range of values essentially depends on the different average altitude of feeding zone. Comparing the geological and hydrogeological features with the results of the geochemical processing, it is reasonable to assume that: the Na-Cl springs are representative of the superficial circuits, with small feeding zones and very low residence times in aquifer; whereas the Ca-HCO3 and Ca-SO4 springs are representative of relatively deep circuits developed in extensive aquifers with high permeability. The first type of springs was used to obtain the relationship between the ?18O ratio and the altitude of rainwater infiltration. Taking into account that they drain a small basin and considering the regulator effect of the aquifers, the isotopic composition of these springs are very similar to the annual average isotopic values of the local meteoric water. This relationship was used to evaluate the average altitude of the feeding area of the second type of springs. All these elements, and some tracer test results available in literature, allowed us to delimit the hydrogeological basins likely drained by the most important springs under study. In addition, for each hydrogeological system, a simplified water balance using meteorological data and the effective infiltration coefficients reported in the literature was performed, verifying that the delimited catchment areas are entirely consistent with the flow rate data of the springs.

  2. Incorporating the social dimension into hydrogeochemical investigations for rural development: the Bir Al-Nas approach for socio-hydrogeology

    NASA Astrophysics Data System (ADS)

    Re, Viviana

    2015-11-01

    A replicable multidisciplinary approach is presented for science-based groundwater management practices: Bir Al-Nas (Bottom-up IntegRated Approach for sustainabLe grouNdwater mAnagement in rural areaS). This approach provides a practical example of the concept of "socio-hydrogeology", a way of incorporating the social dimension into hydrogeological investigations, as reinforced by the translation of the Arabic bir al-nas: "the people's well". To achieve this, hydrogeologists act as "social hydrologists" during their monitoring activities, which often bring them into contact with local communities and end users (and polluters) of water. Not only can they retrieve reliable information about traditional know-how and local issues, but they can also change the public perception of science/scientists to create the basis for mutual collaboration and understanding in view of implementing improved integrated groundwater management. The final outcomes are expected to be an increased awareness of communities at the local level and a clear understanding of their water issues and needs from the very early stages of the investigation. Although the importance of using such methods in groundwater analysis and management is widely recognized, hydrogeological investigations are currently dominated by sectorial approaches that are easier to implement but less sustainable. The pressure of population growth, the shift towards more water-dependent economies, climate change and its impact on water availability will require scientists to use a more integrated approach, such as Bir Al-Nas, when dealing with increasing water pollution and water-scarcity issues.

  3. An integrated geological, hydrogeological and geophysical approach to the characterisation of the aquifer in a contaminated site

    NASA Astrophysics Data System (ADS)

    di Paola, M. A.; Margiotta, S.; Mazzone, F.; Negri, S.

    2005-01-01

    This work sets out a physical - stratigraphical reconstruction of the superficial aquifer in the Brindisi area; this site is recognized to be at significant environmental risk (Law no. 426/98) by the Italian government. Geological, hydrogeological and geophysical methodologies were applied. The geological characterisation consisted of surface and subsoil surveys. The existing stratigraphical, geotechnical and hydrogeological data were collected, processed and homogenised, and the information inserted in a database managed with a specific software (arcview). Hydrogeological surveys were conducted in a number of boreholes uniformly distributed over the studied area. Geophysical prospecting was conducted in the most industrialized part of the area, adjacent to a combined industrial road/conveyor belt - the "Asse Attrezzato" - in order to better describe the site and evaluate the impact of this structure on the environment. This research enabled us to characterise the superficial aquifer of the Brindisi area. The groundwater is of the phreatic type. In the upper part of the deposit, the presence of low permeability sediments (recent continental deposits) means that the groundwater is confined. Subapennine Clays (Lower Pleistocene), present across the whole of the area, form the impermeable base of the aquifer. The deposits that make up the superficial aquifer vary greatly in their permeability. The greatest permeability is associated with the calcarenite deposits (Terraced Deposits, Middle-Upper Pleistocene). The higher the proportion of slime in the granulometric assortment, the lower the permeability of the deposit. The lower section of the aquifer, characterized by the presence of slimy-sandy sediments (Brindisi sands, Lower-Middle Pleistocene), has a lower permeability. The results of the geophysical investigations enabled us to reconstruct in detail the lateral and vertical lithological variations of the geological formations. Furthermore, by supplementing the data from boreholes (direct surveys), the geophysical surveys proved to be useful in that they reduce the need for perforations of the ground, which are potential conduits of pollution.

  4. Incorporating the social dimension into hydrogeochemical investigations for rural development: the Bir Al-Nas approach for socio-hydrogeology

    NASA Astrophysics Data System (ADS)

    Re, Viviana

    2015-07-01

    A replicable multidisciplinary approach is presented for science-based groundwater management practices: Bir Al-Nas (Bottom-up IntegRated Approach for sustainabLe grouNdwater mAnagement in rural areaS). This approach provides a practical example of the concept of "socio-hydrogeology", a way of incorporating the social dimension into hydrogeological investigations, as reinforced by the translation of the Arabic bir al-nas: "the people's well". To achieve this, hydrogeologists act as "social hydrologists" during their monitoring activities, which often bring them into contact with local communities and end users (and polluters) of water. Not only can they retrieve reliable information about traditional know-how and local issues, but they can also change the public perception of science/scientists to create the basis for mutual collaboration and understanding in view of implementing improved integrated groundwater management. The final outcomes are expected to be an increased awareness of communities at the local level and a clear understanding of their water issues and needs from the very early stages of the investigation. Although the importance of using such methods in groundwater analysis and management is widely recognized, hydrogeological investigations are currently dominated by sectorial approaches that are easier to implement but less sustainable. The pressure of population growth, the shift towards more water-dependent economies, climate change and its impact on water availability will require scientists to use a more integrated approach, such as Bir Al-Nas, when dealing with increasing water pollution and water-scarcity issues.

  5. Calendar year 1994 groundwater quality report for the Chestnut Ridge Hydrogeologic Regime, Y-12 Plant, Oak Ridge, Tennessee

    SciTech Connect

    1995-09-01

    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 associated with the US Department of Energy (DOE) Y-12 Plant located on the DOE Oak Ridge Reservation (ORR) southeast of Oak Ridge, Tennessee (Figure 1). These sites lie within the boundaries of the Chestnut Ridge Hydrogeologic Regime (Chestnut Ridge Regime), which is one of three hydrogeologic regimes defined for the purposes of groundwater quality monitoring at the Y-12 Plant (Figure 2). The Environmental Management Department of the Y-12 Plant Health, Safety, Environment, and Accountability (HSEA) Organization manages the groundwater monitoring activities in each regime 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 in accordance with federal, state, and local regulations, DOE Orders, and Lockheed Martin Energy Systems, Inc. (Energy Systems) corporate policy. The annual GWQR for the Chestnut Ridge 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 under the lead of the Y-12 Plant GWPP. Because it contains information needed to comply with reporting requirements of Resource Conservation and Recovery Act (RCRA) interim status assessment monitoring, the Part 1 GWQR is submitted to the Tennessee Department of Environment and Conservation (TDEC) by the RCRA reporting deadline (March 1 of the following CY); Energy Systems submitted the 1994 Part 1 GWQR for the Chestnut Ridge Regime to the TDEC in February 1995 (HSW Environmental Consultants, Inc. 1995a).

  6. The Cerrillos Uplift, the La Bajada Constriction, and Hydrogeologic Framework of the Santo Domingo Basin, Rio Grande Rift, New Mexico

    USGS Publications Warehouse

    Minor, Scott A.

    2006-01-01

    The geologic, geophysical, and hydrogeologic properties of the La Bajada constriction and Santo Domingo Basin, northern New Mexico, result from tectonic and volcanic processes of the late Tertiary and Quaternary Rio Grande rift. An integrated geologic and geophysical assessment in the La Bajada constriction allows development of a geologic framework that can provide input for regional ground-water flow models. These models then can provide better estimates of future water supplies in a region that largely subsists on aquifers in Rio Grande rift basins. The combination of surface geologic investigations (stratigraphic and structural studies; chapters A, B, C, and E), airborne geophysics (aeromagnetic and time-domain electromagnetic surveys; chapters D and F), ground geophysical measurements (gravity and magnetotelluric surveys; chapters D and F), and data from the few wells in the area (chapter G) provides new constraints on the hydrogeologic framework of this area. Summary results of our investigations are synthesized in chapter G. Through-going aquifers consisting of ancestral Rio Grande axial-river sand and gravel and of coarse western-piedmont gravel form the predominant ground-water pathways through the partly buried structural trough defining the La Bajada constriction between Espa?ola and Santo Domingo Basins. Thick, clay-rich Cretaceous marine shales of low hydraulic conductivity form a pervasive regional confining unit within the Cerrillos uplift on the southeast flank of the constriction. Numerous, dominantly north-northwest-striking, intrabasin faults that project part way across the La Bajada constriction create a matrix of laterally and vertically variable hydrogeologic compartments that locally partition and deflect ground-water flow parallel to faults.

  7. Plan of study to define hydrogeologic characteristics of the Madera Limestone in the east mountain area of central New Mexico

    USGS Publications Warehouse

    Rankin, D.R.

    1999-01-01

    The east mountain area of central New Mexico includes the eastern one-third of Bernalillo County and portions of Sandoval, Santa Fe, and Torrance Counties. The area covers about 320 square miles. The Madera Limestone, the principal aquifer in the east mountain area, is the sole source of water for domestic, municipal, industrial, and agricultural uses for many residents. Some water is imported from wells near Edgewood by the Entranosa Water Cooperative, which serves a population of approximately 3,300. The remaining population is served by small water systems that derive supplies locally or by individually owned domestic wells. The population of the east mountain area has increased dramatically over the past 20 years. In 1970, the population of the east mountain area was about 4,000. Demographic projections suggest that approximately 1,000 people per year are moving into the area, and with a growth rate of 3.0 percent the population will be 16,700 in 2000. Consequently, ground-water withdrawals have increased substantially over the past 20 years, and will continue to increase. Little is known about the flow characteristics and hydrogeologic properties of the Madera Limestone. This report describes existing information about the geologic and hydrologic framework and flow characteristics of the Madera Limestone, and presents a plan of study for data-collection activities and interpretive studies that could be conducted to better define the hydrogeologic characteristics of the Madera Limestone. Data-collection activities and interpretive studies related to the hydrogeologic components of the Madera Limestone are prioritized. Activities that are necessary to improve the quantification of a component are prioritized as essential. Activities that could add additional understanding of a component, but would not be necessary to improve the quantification of a component, are prioritized as useful.

  8. Hydrogeological conditions of heavy high-viscous oil distribution in northeast Ural-Povolzhye (Udmurtia, Perm, and Kirov Region)

    SciTech Connect

    Kouznetsova, T.A.

    1995-12-31

    The major question while investigating the origin of subsurface oilfield waters is the development of regional and local hydrogeological oil exploration indices. For determination of the influence of subsurface water on oil pools it is necessary to study paleohydrogeological interrelations and regularities, and the interaction of sub-surface waters and oils. While considering these problems, paleohydrogeological cycles, which include crustal elevation and sea level regression are identified. Nine or ten paleohydrogeological cycles are marked in the Udmurtia, Permian, and Kirov territories, depending on regional paleotectonical history. Mesozoic-Cainozoic tectonic movements are the important cause of generation of heavy high-viscous oil pools.

  9. Hydrogeologic Assessment of the 4-S Land and Cattle CompanyRanch

    SciTech Connect

    Quinn, Nigel W.T.

    2006-04-10

    Hydrogeological assessment of the 4-S Land and Cattle Company (4-S Ranch) was conducted using a combination of field investigations and a survey of available literature from nearby agricultural water districts and other entities. The 4-S Ranch has been able to meet most of its own water needs providing irrigated pasture for beef cattle by an active program of shallow groundwater pumping in these miconfined aquifer above the Corcoran Clay. Comparison of groundwater pumping on the 4-S Ranch property with groundwater pumping in the adjacent Merquin and Stevinson Water Districts shows great similarity in the well screened depths and the quality of the groundwater produced by the well fields. The pump yield for the eight active production wells on the 4-S property are comparable to the production and drainage wells in the adjacent water districts. Like these Districts the 4-S Ranch lies close to the Valley trough in a historic discharge area. The 4-S Ranch is unique in that it is bounded and bisected by several major water conveyance facilities including Bear Creek. Although the large number of potential recharge structures would suggest significant groundwater conjunctive use potential the major well field development has occurred along the length of the Eastside Canal. The Eastside Canal is known to be leaky above the ''A'' Clay the Canal passes through sandy areas and experiences significant groundwater seepage. This seepage can be intercepted by adjacent groundwater wells. Pumping adjacent to, and along the alignment of the Canal, may induce higher rates of seepage from the Eastside Canal. Groundwater quality below and adjacent to the Eastside Canal is very good, reflecting the origin of this diverted water from the Merced River. Most of the pumpage occurs in a depth interval between 30 ft and 130 ft. Safe yield estimates made using the available data show that the 4-S Ranch has sufficient resources to meet its own needs. Further exploitation of the groundwater will be limited if the leakage from the Eastside Bypass, Mariposa Bypass and Bear Creek are insufficient to replace the pumped water on an average annual basis. Should any future lining of the Eastside Canal occur, it would have a significant impact on the groundwater resource potential of the 4-S Ranch and impair the overall quality of the available water supply.

  10. Implementation of a Shallow Groundwater Temperature Manipulation: Linking Hydrogeology, Biogeochemistry, and Aquatic Ecology

    NASA Astrophysics Data System (ADS)

    Wilson, K. P.; Williams, D. D.

    2004-05-01

    Integration of the fields of hydrogeology, biogeochemistry, and meiofaunal and microbial ecology is being used for a shallow groundwater temperature manipulation which simulates global climate change predictions. This study is being conducted on a first order spring-stream, Valley Spring, (southern Ontario, Canada) the headwater of which has been longitudinally divided to a sediment depth of -100 cm. To examine groundwater flow paths and hydraulic conductivity, and to collect physicochemical parameters and nutrient samples, a series of nested piezometers have been installed along three transects across the stream channel. Each nest evaluates water characteristics at depths of -20, -40, -60, -80, and -100 cm. Meiofaunal and microbial samples are collected, using a standpipe corer at the same depths as the piezometer openings. Sampling started in June 2002 and heating of one side of the groundwater began in March 2004. Hydraulic conductivity is heterogeneous with depth ranging from 0.0004 cm/s at -20 cm to 0.00002 cm/s at -100cm, but relatively uniform laterally, ranging from 0.0004 cm/s at 1 m to 0.0003 cm/s at 3 m from the stream channel. Pre-manipulation water temperatures decrease with depth in the summer, ranging from 14.5° C at the surface to 12.5° C at -100 cm. In contrast, temperature increases from 13.1 at the surface to 14.5° C at -100 cm in the fall. Temperature during the winter and spring are within 1.0° C from the surface to -100 cm, but range from 9.0-9.5° C in the winter and 8.0-7.0° C in the spring, respectively. Pre-manipulation nitrate concentrations are higher in winter (0.45 mg/l) then in summer (0.28 mg/l) and decrease with depth. Ammonia shows an inverse relationship, with lower concentrations in winter than summer (0.19 and 0.32 mg/l, respectively) and increase with depth. Dissolved organic carbon (DOC) also shows an increase with depth, ranging from 1.6 mg/l at the surface to 6.23 mg/l at -100 cm. Pre-manipulation meiofaunal abundance shows no difference between seasons but higher densities at -20cm then at all other depths. The most common meiofaunal taxa include Harpacticoida, Nematoda, Ostracoda, Chironomidae, Collembola, and Hydracarina. Plecoptera and Hymenoptera larvae are also found on occasion above -60 cm.

  11. Evaluating Traditional Hydrogeologic Characterization Approaches in a Highly Heterogeneous Glaciofluvial Aquifer

    NASA Astrophysics Data System (ADS)

    Alexander, M.; Berg, S. J.; Illman, W.

    2009-05-01

    Hydraulic conductivity (K) and specific storage (Ss) estimates are two of the most essential parameters when designing transient groundwater flow models which are commonly used in contaminant transport and water resource investigations. The purpose of this study was to evaluate the effectiveness of traditional hydrogeologic characterization approaches in a highly heterogeneous glaciofluvial aquifer at the North Campus Research Site (NCRS) situated on the University of Waterloo campus. The site is instrumented with four Continuous Multichannel Tubing (CMT) wells containing a total of 28 monitoring points and a multi-screen well used for pumping at different elevations. Continuous soil cores to a depth of approximately 18 m were collected during the installation of the CMTs and the multi-screen well. The cores were subsequently characterized using the Unified Soil Classification System and grain size analysis. Samples were obtained from the core at approximately 10 cm increments and a falling head permeameter was used to make 471 K estimates. The estimates from the falling head permeameter showed K to vary from 10-4 - 10-10 m/s illustrating the highly heterogeneous nature of the aquifer at the NCRS. A geostatistical analysis performed on the core K dataset yielded a strongly heterogeneous K field for the site. K and Ss estimates were also obtained via slug tests in the CMT ports through type curve analysis. Cross-hole pumping tests were conducted using the center multi-screened well and the 4 CMTs installed in a 5-spot pattern. Pumping was conducted in 7 zones using a straddle packer system and the corresponding drawdown responses were recorded in 28 zones in the CMTs and 3 zones in the center well using pressure transducers. The various K and Ss estimates were then evaluated by simulating the transient drawdown data using a 3D forward numerical model constructed using Hydrogeosphere (Therrien et al., 2005). Simulation was conducted using 3 separate K and Ss fields: 1) a homogeneous case with K and Ss estimates obtained by averaging equivalent K and Ss values from the cross-hole pumping tests, 2) a layered heterogeneous case with K and Ss estimates from the slug tests and 3) a heterogeneous case with the kriged K from the permeameter tests and equivalent Ss from the slug tests. Results showed that, while drawdown predictions, in general, improved as more complexity was introduced into the model, the ability to make accurate drawdown predictions at all of the CMT ports was inconsistent. These results suggest that new techniques may be required to accurately capture subsurface heterogeneity for improved predictions of drawdown responses. Accurate predictions of drawdown responses should lead to improved modeling of contaminant transport and remediation designs.

  12. Geodetic component of the monitoring of tectonic and hydrogeological activities in Kopacki Rit Nature Park

    NASA Astrophysics Data System (ADS)

    Dapo, Almin; Pribicevic, Bosko

    2013-04-01

    Based on the European and global experience, the amplitude change in the structural arrangement caused by recent tectonic movements, can be most accurately determined by repeated precise GPS measurements on specially stabilized geodetic and geodynamic points. Because of these reasons, the GPS method to determine the movements on specially stabilized points in the Nature park Kopacki rit is also applied in this project. Kopacki rit Nature Park is the biggest preserved natural flooded area on the Danube. It is spread over 23 000 hectares between the rivers Danube and Drava and is one of the biggest fluvial wetland valleys in Europe. In 1993 it was listed as one of internationally valuable wetlands according to the Ramsar Convention. By now in Kopacki rit there have been sights of about 295 bird species, more than 400 species of invertebrates and 44 types of fish. Many of them are globally endangered species like, white tailed eagle, black stork and prairie hawk. It's not rare to come across some deer herds, wild boars or others. Today's geological and geomorphological relations in the Nature park Kopacki rit are largely the result of climate, sedimentary, tectonic and anthropogenic activity in the last 10,000 years. Unfortunately the phenomenon of the Kopacki rit Nature park is in danger to be over in the near future due to those and of course man made activities on the Danube river. It is trough scientific investigations of tectonic and hydrogeological activities that scientist from University of Zagreb are trying to contribute to wider knowledge and possible solutions to this problem. In the year 2009 the first GPS campaign was conducted, and the first set of coordinates of stabilized points was determined which can be considered zero-series measurements. In 2010 a second GPS campaign was conducted and the first set of movements on the Geodynamic Network of Kopacki Rit Nature Park was determined. Processing GPS measurements from 2009 and 2010 was carried out in a scientific software with multipoint solutions GAMIT / GLOBK, using Kalman filter to determine the velocity from discrete campaigns. This paper presents the performed measurements, processing and analysis of the results, which indicate that there are geodynamicaly significant developments.

  13. Hazard connected to railway tunnel construction in karstic area: applied geomorphological and hydrogeological surveys

    NASA Astrophysics Data System (ADS)

    Casagrande, G.; Cucchi, F.; Zini, L.

    2005-02-01

    In a mature karstic system, the realisation of galleries using the methodology of railway tunnel boring machine (TBM) involves particular problems due to the high risk of interference with groundwater (often subject to remarkable level variations) and with cavities and/or thick fill deposits. In order to define groundwater features it is necessary to investigate both hydrodynamic and karstification. To define and quantify the karst phenomenon in the epikarst of the Trieste Karst (Italy), an applied geomorphological approach has been experimented with surface and cavity surveys. The surface surveys have contributed to determining the potential karst versus the different outcropping lithologies and to define the structural setting of the rocky mass also through the realisation of geostructural stations and the survey of the main lines thanks to photo-interpretation. Moreover, all the dolines and the cavities present in the area interested by the gallery have been studied by analysing the probable extension of caves and/or of the secondary fill deposits and by evaluating the different genetic models. In an area 900m large and 27km long, which has been studied because of the underground karst, there are 41 dolines having diameters superior to 100m and 93 dolines whose diameters range between 100 and 50m; the dolines whose diameters are inferior to 50m are 282. The entrances of known and registered cavities in the cadastre records are 520. The hypogeal surveys have shown 5 typologies in which it has been possible to group all the cavities present in a hypothetical intersection with the excavation. The comparison between surface and hypogeal structural data and the direction of development of cavities has allowed for the definition of highly karstified discontinuity families, thus having a higher risk. The comparison of the collected data has enabled to identify the lithologies and areas having major risk and thus to quantify the probability of intersection with the different cavity typologies for each area. To make an example, out of 27000m of studied gallery 3930 are the metres expected to be at very high "karst risk". Out of these, as a whole 310 are risky because of the probable presence of gallery cavities, 2170 because of the probable presence of pits and sinkholes diffusely present under the dolines, and along 1450m karst is particularly intense. Moreover, 2200 should be the metres in which the rocky mass will be particularly divided because of tectonic causes. From a hydrogeological point of view a monitoring of water level has started to quantify water excursion, due to closeness of the railway tunnel to the mean water level. First results related to galleries intersection are here presented.

  14. Hydrogeologic and Hydrochemical Studies in a Semi-arid Watershed in Northern Mexico

    NASA Astrophysics Data System (ADS)

    Kretzschmar, T.; Vazquez, R.; Hinojosa, A.

    2006-12-01

    Within the Baja California panhandle exist quite a significant number of valleys which hydrogeology conditions are of great importance for the communities of the region. The Guadalupe Valley for example, located 30 km Northeast of Ensenada, hosts an important wine industry which presents a mayor factor for agriculture and tourism in Baja California. The irrigation is carried out basically by groundwater extracted from quaternary sediments filling this post-Miocene depression. Besides the intensive usage of the water by the wine industry in the Guadalupe Valley, the local waterworks installed in 1985 a gallery of 10 wells extracting around 320 l/s or 30 % of the total water extraction in the valley to supply the city of Ensenada with drinking water. A total of more than 500 wells with a combined annual consumption of about 28 Mio m3 are at the moment active in the valley. In the arid portions of northern Mexico Mountain front recharge presents an important recharge source for the alluvial aquifers. Other important sources directly related to precipitation are direct infiltration, recharge by surface water runoff in the arroyos as well as by active fault systems. The principal recharge sources for the Guadalupe Valley aquifer are the Sierra Juárez and the Guadalupe River. To be able to address the state of equilibrium of aquifer, recharge estimates for the watershed were calculated determining the runoff/infiltration relationships obtained by curve number determinations combined with the interpretation of satellite images. These results were integrated into an evaluation and hydrologic modeling of the hydrologic data pointing towards differences of up to over 50 percent in the recharge estimation in comparison to earlier studies carried out in the area. Furthermore hydrochemical and isotopic studies were carried out to show the effects of the excessive ground water extraction on the water quality of the aquifer. The hydrochemical data indicate that intense use of the water resource leads to a degradation of the water quality of the aquifer basically being reflected by an increase in sulfates, sodium and chloride. Combining the results with the hydrologic data and modeling it was possible outline high impact zones with steep water level drops of up to 15 m and high water quality deterioration as well as low impact zones with shallow water level fluctuation less tan on meter and stable water quality. These results will finally lead to a proposal how to guide the Guadalupe watershed towards a sustainable management of the aquifer.

  15. Hydrogeology and results of injection tests at waste-injection test sites in Pinellas County, Florida

    USGS Publications Warehouse

    Hickey, John J.

    1982-01-01

    Potential benefits or hazards to freshwater resources could result from subsurface injection of treated wastewater. Recognizing this, the U.S. Geological Survey, in cooperation with Pinellas County and the city of St. Petersburg, undertook an evaluation of the hydrogeology and injection of wastewater at proposed test sites on the Pinellas peninsula. The injection sites are underlain by sedimentary rocks ranging in age from Cretaceous to Pleistocene. Lower Eocene carbonate rocks were penetrated to a maximum depth of 3,504 feet and were found to have relatively low water yields. The most permeable part of the investigated section was in rocks of middle Eocene age within the Floridan aquifer. At the injection sites, the Floridan aquifer was subdivided into four permeable zones and three semiconfining beds. The test injection zone is within the Avon Park Limestone, the most productive of the identified permeable zones, with a transmissivity of about 1,000,000 feet squared per day. Two semiconfining beds are above the injection zone in the Suwannee Limestone and Ocala Limestone and have vertical hydraulic conductivities estimated to range from about 0.1 to 1 foot per day where these beds do not contain clay. Limited fresh ground-water supplies exist in the Floridan aquifer within the Pinellas peninsula. At all test sites, chloride concentration in the injection zone ranged from 19,000 to 20,000 milligrams per liter. Injection tests ranging in duration from 3 to 91.1 days were run at three different sites. Pressure buildup occurred in permeable zones above and below the injection zone during these tests. Calculated pressure buildup in observation wells close to and at some distance from the test wells was typically less than 1 pound per square inch. Injection and formation water will probably move slowly through the semiconfining bed overlying the injection zone, and long-term injection tests will be needed to determine the effectiveness of these beds to retard flow. The injected water was well mixed with the native formation water, which, in part, is a direct consequence of the fractures in the injection zone.

  16. Extracting Hydrogeology from Heliborne Dual Moment Transient Electromagnetic Investigation in Geologically Divergent Terrenes

    NASA Astrophysics Data System (ADS)

    Ahmed, S.; Chandra, S.; Auken, E.; Verma, S. K.

    2014-12-01

    Comprehensive knowledge of aquifer system is an important requisite for its effective management in India. Geological formations are complex and variable, punctual and scarce information are not adequate to understand, asses and manage them. Continuous data acquisition, their interpretation and integration with available geological/geophysical information is the solution. Heliborne dual moment transient electromagnetic (HeliTEM) and magnetic (HeliMAG) measurements have been carried out in divergent geological terrenes in India comprising Gangetic alluvium, Tertiary sediments underlying the Thar desert, Deccan basalts and Gondwana sediments, weathered and fractured granite gneisses and schists and the coastal alluvium with Tertiary sediments. The survey was carried out using state of the art equipment SkyTEM. The paper presents a synopsis of the results of the HeliTEM surveys that have helped in obtaining continuous information on the geoelectrical nature of sub-surface. HeliTEM data were supported by a number of ground geophysical surveys. The results provide the 3D subsurface structures controlling the groundwater conditions, the regional continuity of probable aquifers, the variations in lithological character and the quality of water in terms of salinity. Specialized features pertaining to hydrogeological characteristics obtained from this study are as follows: ? A clear delineation of clay beds and their spatial distribution providing the multi-layered aquifer setup in the Gangetic plains. ? Delineation of low resistivity zones in the quartzite below the over exploited aquifers indicating the possibility of new aquifers. ? Presence of freshwater zones underneath the saline water aquifers in the thick and dry sands in deserts. ? Clear demarcation of different lava flows, mapping the structural controls and highly porous zones in the contact of basalts and Gondwanas. ? A complete and continuous mapping of weathered zone in crystalline hard rock areas providing information on the recharge zones. ? The setting of multi-layered aquifer and different zones of salt water intrusion in the coastal sedimentary formations. The study has helped in establishing an appropriate cost-effective strategy for 3D mapping of aquifers on a regional scale providing valuable inputs to perform aquifer modeling

  17. Optimization of hydrogeological parameters of riverbank filtrated aquifers of the Szendendre Island using natural tracers

    NASA Astrophysics Data System (ADS)

    Kármán, K.; Fórizs, I.; Deák, J.; Szabó, Cs.

    2009-04-01

    Hungary's capital, Budapest, and a number of surrounding settlements are supplied with drinking water largely from the bank filtered aquifer at Szentendre Island of the Danube River lying to the north of the city. Precise knowledge of regional hydrogeological processes in riverbank filtrated aquifers are indispensable for aquifer protection and adequate quality water supply. To reach this goal, the origin and velocity/transit time of filtrating water was studied: stable isotopic, e.g. O-18 tracing measurement. Basis of these studies was the fact that d18O of Danube water (-10.9 % as a mean) differs from the locally infiltrated precipitation (shallow groundwater, -9,5 %) as a consequence of the „altitude effect". Szentendre Island itself sits mainly on Tertiary marine clayey sediments. These are topped by gravels and sands of Pleistocene age. Surface formations consist of semi-consolidated shifting sands and a few floodplain horizons. Widespread gravel formations on the island provide the basis for one of the largest volumes of abstraction of riparian-water in Europe. Supplied water comes largely from the river, and is supplemented by locally infiltrated precipitation. While filtrating from the watercourse through porous sediments to the wells, water is cleared from physical as well as biological contaminations. Water samples were taken on a daily basis from the Vác arm of the Danube, as well as from the water producing Kisoroszi-2 horizontal collector well, lying at the bank of Danube on the Szentendre Island. Collectors of this well are aligned to two horizons at the depth of ca. 12 m in the Pleistocene gravels. Electric conductivity, temperature and pH were measured daily, and were supplemented by d18O measurements for characterizing the region between the Danube and the well. To study larger scale systems, at first three, then six monitoring wells were sampled for the parameters stated above. These wells are aligned along a line connecting the two river arms around the island, thus provide information about the inner parts of the island. Highest conductivity and d18O values for monitoring wells were expected in the central part of the island. However, one of the marginal wells proved to show the highest measured values, suggesting extraordinary behavior of the local flow regime. Anomalous behavior of conductivity and oxygen isotopic values (both higher in the Danube than in the collector well) were detected, indicating conditions different from that to be predicted by a simple conceptual model. In accordance with seasonal variations during the test period, river temperature fell almost 8 °C, while well temperature increased linearly about 1.4 °C. These values suggest more complicated flow/storage conditions.

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

    NASA Astrophysics Data System (ADS)

    Mayaud, Cyril; Winkler, Gerfried; Reichl, Peter

    2015-04-01

    Fault zones are the result of tectonic processes and are geometrical features frequently encountered in carbonate aquifer systems. They can hamper the fluid migration (hydrogeological barriers), propagate the movement of fluid (draining conduits) or be a combination of both processes. Numerical modelling of fractured carbonate aquifer systems is strongly bound on the knowledge of a profound conceptual model including geological and tectonic settings such as fault zones. In further consequence, numerical models can be used to evaluate the conceptual model and its introduced approximations. The study was conducted in a fractured carbonate aquifer built up by permomesozoic dolo/limestones of the Semmering-Wechsel complex in the Eastern Alps (Austria). The aquifer has an assumed thickness of about 200 m and dips to the north. It is covered by a thin quartzite layer and a very low permeable layer of quartz-phyllite having a thickness of up to several hundred meters. The carbonate layer crops out only in the southern part of the investigation area, where it receives autogenic recharge. The geological complexity affects some uncertainties related to the extent of the model area, which was determined to be about 15 km². Three vertical fault zones cross the area approximately in a N-S direction. The test site includes an infrastructural pilot tunnel gallery of 4.3 km length with two pumping stations, respectively active since August 1997 and June 1998. The total pumping rate is about 90 l/s and the drawdown data were analysed analytically, providing a hydraulic conductivity of about 5E-05 m/s for the carbonate layer. About 120 m drawdown between the initial situation and situation with pumping is reported by piezometers. This led to the drying up of one spring located at the southern border of the carbonates. A continuum approach using MODFLOW-2005 was applied to reproduce numerically the observed aquifer behaviour and investigate the impact of the three fault zones. First simulations were done under laminar flow conditions, an attempt allowing nonlinear flow with a new released package was implemented later. Preliminary results show that the implementation of the three faults zones with a much lower hydraulic conductivity compared to the aquifer is essential to reproduce properly both situations with and without pumping. This approves the high impact of fault zones on groundwater flow in fractured aquifer systems. Finally, this example shows that numerical modelling can help to reduce the uncertainties of conceptual models.

  19. Arsenic in midwestern glacial deposits? Occurrence and relation to selected hydrogeologic and geochemical factors

    USGS Publications Warehouse

    Thomas, Mary Ann

    2003-01-01

    Ground-water-quality data collected as part of 12 U.S. Geological Survey National Water-Quality Assessment studies during 1996-2001 were analyzed to (1) document arsenic occurrence in four types of gla-cial deposits that occur in large areas of the Midwest, (2) identify hydrogeologic or geochemical factors asso-ciated with elevated arsenic concentrations, and (3) search for clues as to arsenic source(s) or mechanism(s) of mobilization that could be useful for designing future studies. Arsenic and other water-quality constituents were sampled in 342 monitor and domestic wells in parts of Illinois Indiana Ohio Michigan and Wisconsin. Arsenic was detected (at a concentration >1 ?g/L) in one-third of the samples. The maximum concentration was 84 ?g/L, and the median was less than 1 ?g/L. Eight percent of samples had arsenic concentrations that exceeded the U.S. Environmental Protection Agency Maximum Contaminant Level (MCL) of 10?g/L. Samples were from four aquifer types?confined valley fill, unconfined valley fill, outwash plain, and till with sand lenses. Highest arsenic concentrations were found in reducing waters from valley-fill depos-its. In confined valley fill, all waters were reducing and old (recharged before 1953), and almost half of sam-ples had arsenic concentrations greater than the MCL. In unconfined valley fill, redox conditions and ages were varied, and elevated arsenic concentrations were sporadic. In both types of valley fill, elevated arsenic concentrations are linked to the underlying bedrock on the basis of spatial relations and geochemical correla-tions. In shallow (150 ft), all deep wells were from a distinctive aquifer type (confined valley fill). It is not known whether wells at similar depths in other aquifer types would produce waters with simi-larly high arsenic concentrations. Correlations of arsenic with fluoride, strontium, and barium suggest that arsenic might be related to epi-genetic (Mississippi Valley-type) sulfide deposits in Paleozoic bedrock. Arsenic is typically released from sulfides by oxidation, but in the current study, the highest arsenic concentrations in glacial deposits were detected in reducing waters. Therefore, a link between epigenetic sulfides and elevated arsenic concentrations in glacial deposits would probably require a multi-step process.

  20. Hydrogeologic reconnaissance of the Mekong Delta in South Vietnam and Cambodia

    USGS Publications Warehouse

    Anderson, Henry R.

    1978-01-01

    The present report describes the results of a hydrogeologic reconnaissance in the Mekong Delta region by the writer, a hydrogeologist of the U.S. Geological Survey, while on assignment as an adviser to the Vietnamese Directorate of Water Supply from October 1968 to April 1970 under the auspices of the U.s. Agency for International Development. The delta of the Mekong River, comprising an area of about 70,000 square kilometres in South Vietnam and Cambodia, is an almost featureless plain rising gradually from sea level to about 5 metres above sea level at its apex 300 kilometres inland. Most of the shallow ground water in the Holocene Alluvium of the delta in Vietnam is brackish or saline down to depths of 50 to 100 metres. Moreover, in the Dong Thap Mu?oi (Plain of Reeds) the shallow ground water is alum-bearing. Locally, however, perched bodies of fresh ground water occur in ancient beach and dune ridges and are tapped by shallow dug wells or pits for village and domestic water supply. The Old Alluvium beneath the lower delta contains freshwater in some areas, notably in the Ca Mau Peninsula and adjacent areas, in the viciniy of Bau Xau near Saigon, and in the Tinh Long An area. Elsewhere in the lower delta both the Holocene and Old Alluvium may contain brackish or saline water from the land surface to depths of as much as 568 metres, as for example in Tinh Vinh Binh. Ground water in the outcrop area of Old Alluvium northwest of Saigon is generally fresh and potable, but high iron and low pH are locally troublesome. Although considerable exploratory drilling for ground water down to depths of as much as 568 metres has already been completed, large areas of the delta remain yet to be explored before full development of the ground-water potential can be realized. With careful development and controlled management to avoid saltwater contamination, however, it is estimated that freshwater aquifers could provide approximately 80 percent of existing needs for village and small municipal supplies in the delta.

  1. Hydrogeological investigation of shallow aquifers in an arid data-scarce coastal region (El Daba'a, northwestern Egypt)

    NASA Astrophysics Data System (ADS)

    Yousif, Mohamed; van Geldern, Robert; Bubenzer, Olaf

    2015-10-01

    Hydrogeological investigations in arid regions are particularly important to support sustainable development. The study area, El Daba'a in northwestern Egypt, faces scarce water resources as a result of reported climate change that particularly affects the southern Mediterranean coast and increases stress on the local groundwater reserves. This change in climate affects the area in terms of drought, over-pumping and unregulated exploration of groundwater for irrigation purposes. The hydrogeological investigation is based on a multidisciplinary data-layer analysis that includes geomorphology, geology, slope, drainage lines, soil type, structural lineaments, subsurface data, stable isotopes, and chemical analyses. The study area contains Pleistocene and middle Miocene marine limestone aquifers. Based on lithology and microfacies analysis, the middle Miocene aquifer is subdivided into two water-bearing zones. The area is affected by sets of faults and anticline folds, and these structures are associated with fractures and joints that increase permeability and facilitate the recharge of groundwater. Stable isotope data indicate that groundwater of both the Pleistocene and middle Miocene aquifers is recharged by modern precipitation. The high salinity values observed in some groundwater wells that tap both aquifers could be attributed to leaching and dissolution processes of marine salts from the aquifers' marine limestone matrix. In addition, human activities can also contribute to an increase in groundwater salinity. A future water exploration strategy, based on the results from the multidisciplinary data-layer analysis, is proposed for the area. The derived scientific approach is transferable to other arid coastal areas with comparable conditions.

  2. Imaging 4-D hydrogeologic processes with geophysics: an example using crosswell electrical measurements to characterize a tracer plume

    NASA Astrophysics Data System (ADS)

    Singha, K.; Gorelick, S. M.

    2005-05-01

    Geophysical methods provide an inexpensive way to collect spatially exhaustive data about hydrogeologic, mechanical or geochemical parameters. In the presence of heterogeneity over multiple scales of these parameters at most field sites, geophysical data can contribute greatly to our understanding about the subsurface by providing important data we would otherwise lack without extensive, and often expensive, direct sampling. Recent work has highlighted the use of time-lapse geophysical data to help characterize hydrogeologic processes. We investigate the potential for making quantitative assessments of sodium-chloride tracer transport using 4-D crosswell electrical resistivity tomography (ERT) in a sand and gravel aquifer at the Massachusetts Military Reservation on Cape Cod. Given information about the relation between electrical conductivity and tracer concentration, we can estimate spatial moments from the 3-D ERT inversions, which give us information about tracer mass, center of mass, and dispersivity through time. The accuracy of these integrated measurements of tracer plume behavior is dependent on spatially variable resolution. The ERT inversions display greater apparent dispersion than tracer plumes estimated by 3D advective-dispersive simulation. This behavior is attributed to reduced measurement sensitivity to electrical conductivity values with distance from the electrodes and differential smoothing from tomographic inversion. The latter is a problem common to overparameterized inverse problems, which often occur when real-world budget limitations preclude extensive well-drilling or additional data collection. These results prompt future work on intelligent methods for reparameterizing the inverse problem and coupling additional disparate data sets.

  3. Hydrogeologic framework of the shallow aquifers in the Ikom-Mamfe Embayment, Nigeria using an integrated approach

    NASA Astrophysics Data System (ADS)

    Edet, Aniekan; Okereke, C. S.

    2014-04-01

    A detailed hydrogeological investigation was carried out in the Ikom-Mamfe Embayment of Nigeria using lineaments, geological, geoelectrical, and hydraulic parameters. The objective was to assess aquifer framework and resource potential of the area. The study was carried out because the aquifers are of particular importance as they are more or less the only source of water supply available for the rural population. In addition, expanding communities will trigger increase in water demand that will translate to more dependence on groundwater. The study identified four major hydrostratigraphic units: Mamfe (oldest), Ezillo, Amaseri and intrusives (youngest). A comprehensive investigation of the basin revealed its lateral and vertical dimensions and hydrogeological characteristics. Moreover, study of lineaments, aquifer parameters, water level fluctuations confirmed the heterogeneity of the aquifers and their potentials to rural water supply. Water rock interactions, mainly silicate weathering, explain the groundwater compositions which are Ca-HCO3, Ca-HCO3-Cl and Ca-Na-HCO3. The water quality is good for domestic and agricultural uses. However, in terms of vulnerability of the aquifers to pollution, 80% of the Ikom-Mamfe Embayment has been classified as medium to high vulnerability.

  4. Hydrogeologic characterization of wells HTH-1, UE18r, UE6e, and HTH-3, Nevada Test Site

    SciTech Connect

    Lyles, B.F.; McKay, W.A.; Chapman, J.B.; Tyler, S.W.

    1991-06-01

    Monitoring for the migration of contaminants in groundwater or for the proper design of nuclear test emplacement holes at the Nevada Test Site (NTS) requires proper placement and completion of monitoring wells. This is only possible if the hydrogeologic system is understood in a regional and local context, necessitating data from existing wells and boreholes. Though the NTS Groundwater Characterization Project will be drilling wells, their great expense limits the number of new wells. However, there are many existing boreholes and wells on the NTS which have not been completely evaluated hydrologically. Some of these are incorporated in the Long Term Hydrologic Monitoring Program (LTHMP) of the US Environmental Protection Agency (EPA), others are related to the testing programs. In all cases, additional site investigation in necessary to properly interpret the hydrogeologic data from these wells. Monitoring wells on the NTS are poorly characterized with regard to aquifers penetrated, vertical hydraulic gradients, and vertical variations in water quality. One of the goals of the well validation program was to gain a thorough understanding of the parameters needed to interpret the source and fate potential hazardous and radioactive substances that may be detected in these wells in the future. One of the most critical parameters for monitoring is the knowledge of what aquifer or geologic unit is being sampled when a water sample is collected. Pumped water samples are weighted most heavily to the water quality of the most productive (highest transmissivity) aquifer penetrated by the well.

  5. A Hydrogeologic Field Area Encourages Learning of Isotope Hydrology, Geologic Imprint on Water Quality, and Trace Element Hydrochemistry

    NASA Astrophysics Data System (ADS)

    Hibbs, B. J.

    2014-12-01

    The Santa Monica Mountains of Southern California affords an excellent opportunity for training students on geologic imprints on stream and groundwater quality. With salinity varying from 500 mg/L TDS in streams fed from groundwater in low solubility sandstones, to 4000 mg/L TDS in streams fed from high solubility and gypsum bearing siltstones and mudstones, the role of geology on natural stream and groundwater chemistry is profound. Use of imported water from Northern California on urban landscapes that is isotopically distinct from locally sourced "native" waters provides an opportunity for students to trace and quantify the percentage of imported versus native water sources in the Santa Monica Mountains streams using stable water isotopes. Furthermore, the presence of natural selenium and uranium in certain types of strata and higher oxidation potential created by anthropogenic nitrate in groundwater provides students with opportunities to learn of trace element hydrochemistry and redox potential in natural and nutrient-contaminated strata. Teams of students have evaluated these processes in this exceptional natural hydrogeological laboratory in our Watershed Analysis, Field Methods, and Water Quality courses. The opportunities for learning hydrogeological processes in this natural field laboratory prepare students for careers in water resources in Southern California and elsewhere.

  6. Hydrogeologic Framework, Groundwater Movement, and Water Budget in the Chambers-Clover Creek Watershed and Vicinity, Pierce County, Washington

    USGS Publications Warehouse

    Savoca, Mark E.; Welch, Wendy B.; Johnson, Kenneth H.; Lane, R.C.; Fasser, Elisabeth T.

    2010-01-01

    This report presents information used to characterize the groundwater-flow system in the Chambers-Clover Creek Watershed and vicinity, and includes descriptions of the geology and hydrogeologic framework; groundwater recharge and discharge; groundwater levels and flow directions; seasonal groundwater level fluctuations; interactions between aquifers and the surface-water system; and a water budget. The study area covers about 706 square miles in western Pierce County, Washington, and extends north to the Puyallup River, southwest to the Nisqually River, and is bounded on the south and east by foothills of the Cascade Range and on the west by Puget Sound. The area is underlain by a northwest-thickening sequence of unconsolidated glacial and interglacial deposits which overlie sedimentary and volcanic bedrock units that crop out in the foothills along the southern and southeastern margin of the study area. Geologic units were grouped into 11 hydrogeologic units consisting of aquifers, confining units, and an underlying bedrock unit. A surficial hydrogeologic unit map was developed and used with well information from 450 drillers' logs to construct 6 hydrogeologic sections, and unit extent and thickness maps. Groundwater in unconsolidated glacial and interglacial aquifers generally flows to the northwest towards Puget Sound, and to the north and northeast towards the Puyallup River. These generalized flow patterns likely are complicated by the presence of low permeability confining units that separate discontinuous bodies of aquifer material and act as local groundwater-flow barriers. Water levels in wells completed in the unconsolidated hydrogeologic units show seasonal variations ranging from less than 1 to about 50 feet. The largest groundwater-level fluctuation (78 feet) observed during the monitoring period (March 2007-September 2008) was in a well completed in the bedrock unit. Synoptic streamflow measurements made in September 2007 and July 2008 indicated a total groundwater discharge to streams in the study area of 87,310 and 92,160 acre-feet per year, respectively. The synoptic streamflow measurements show a complex pattern of gains and losses to streamflows that varies throughout the study area, and appears to be influenced in places by local topography. Groundwater discharge occurs at numerous springs in the area and the total previously reported discharge of springs in the area is approximately 80,000 acre-feet per year. There are, in addition, many unmeasured springs and the total spring discharge in the area is unknown. The water-budget area (432 mi2 located within the larger study area) received an annual average (September1, 2006, to August 31, 2008) of about 1,025,000 acre-ft or about 45 inches of precipitation a year. About 44 percent of precipitation enters the groundwater system as recharge. Almost one-half of this recharge (49 percent) discharges to the Puyallup and Nisqually Rivers and leaves the groundwater system as submarine groundwater discharge to Puget Sound. The remaining groundwater recharge discharges to streams (20 percent) and springs (18 percent) or is withdrawn from wells (13 percent)

  7. Hydrogeology of a fractured shale (Opalinus Clay): Implications for deep geological disposal of radioactive wastes

    NASA Astrophysics Data System (ADS)

    Gautschi, Andreas

    2001-01-01

    As part of the Swiss programme for high-level radioactive-waste disposal, a Jurassic shale (Opalinus Clay) is being investigated as a potential host rock. Observations in clay pits and the results of a German research programme focusing on hazardous waste disposal have demonstrated that, at depths of 10-30 m, the permeability of the Opalinus Clay decreases by several orders of magnitude. Hydraulic tests in deeper boreholes (test intervals below 300 m) yielded hydraulic conductivities <10-12 m/s, even though joints and faults were included in some of the test intervals. These measurements are consistent with hydrogeological data from Opalinus Clay sections in ten tunnels in the Folded Jura of northern Switzerland. Despite extensive faulting, only a few indications of minor water inflow were encountered in more than 6,600 m of tunnel. All inflows were in tunnel sections where the overburden is less than 200 m. The hydraulic data are consistent with clay pore-water hydrochemical and isotopic data. The extensive hydrogeological data base - part of which derives from particularly unfavourable geological environments - provides arguments that advective transport through faults and joints is not a critical issue for the suitability of Opalinus Clay as a host rock for deep geological waste disposal. Résumé. Dans le cadre du programme suisse de stockage de déchets hautement radioactifs, une formation argileuse du Jurassique, l'argile à Opalinus, a été étudiée en tant que roche hôte potentielle. Des observations dans des cavités dans l'argile et les résultats du programme de recherche allemand consacré au stockage de déchets à risques ont démontré que, à des profondeur de 10 à 30 m, la perméabilité des argiles à Opalinus décroît de plusieurs ordres de grandeur. Des essais hydrauliques dans des forages plus profonds (intervalles de test á une profondeur de plus de 300 m) ont donné des conductivités hydrauliques inférieures à 10-12 m/s, même lorsque des fractures et des failles existaient dans certains des intervalles d'essais. Ces mesures sont conformes aux données hydrogéologiques tirées du recoupement des argiles à Opalinus par dix tunnels du Jura plissé du nord de la Suisse. Malgré une tectonique intense, peu de manifestations de faibles venues d'eau ont été rencontrées dans plus de 6600 m de tunnel. Toutes les venues d'eau se sont produites dans des sections de tunnel où le recouvrement est inférieur à 200 m. Les données hydrauliques sont en bon accord avec les données hydrochimiques et isotopiques de l'eau porale des argiles. En se basant sur le grand nombre de données hydrogéologiques, qui portent en partie sur les environnements géologiques particulièrement peu propices, on peut avancer que le transport advectif le long des failles et des fractures n'est pas un facteur susceptible de remettre en question le choix de l'argile à Opalinus comme roche hôte pour le stockage de déchets radioactifs en formation géologique profonde. Resúmen. Dentro del programa suizo de eliminación de residuos radiactivos de alta actividad, se está investigando la posibilidad de utilizar unos esquistos Jurásicos (Arcilla Opalina) como depósito geológico. Las observaciones efectuadas en pozos en arcilla y los resultados de un programa de estudio alemán sobre eliminación de residuos peligrosos han demostrado que, a profundidades de entre 10 y 30 m, la permeabilidad de la Arcilla Opalina decrece en varios órdenes de magnitud. Los ensayos hidráulicos realizados en sondeos más profundos (en intervalos situados a más de 300 m) proporcionaron conductividades hidráulicas inferiores a 10-12 m/s, pese a que algunos de los intervalos interceptaban juntas y fallas. Estas medidas son coherentes con los datos hidrogeológicos de las secciones de Arcilla Opalina existentes en 10 túneles del Jurásico Plegado, al norte de Suiza. A pesar de las fallas extensivas, apenas se hallaron indicios de entrada de agua en los más de 6.600 m de túnel. Todos los flujos tenían lugar en secciones del túnel q

  8. Hydrogeologic framework of the North Fork and surrounding areas, Long Island, New York

    USGS Publications Warehouse

    Schubert, Christopher E.; Bova, Richard G.; Misut, Paul E.

    2004-01-01

    Ground water on the North Fork of Long Island is the sole source of drinking water, but the supply is vulnerable to saltwater intrusion and upconing in response to heavy pumping. Information on the area?s hydrogeologic framework is needed to analyze the effects of pumping and drought on ground-water levels and the position of the freshwater-saltwater interface. This will enable water-resource managers and water-supply purveyors to evaluate a wide range of water-supply scenarios to safely meet water-use demands. The extent and thickness of hydrogeologic units and position of the freshwater-saltwater interface were interpreted from previous work and from exploratory drilling during this study. The fresh ground-water reservoir on the North Fork consists of four principal freshwater flow systems (referred to as Long Island mainland, Cutchogue, Greenport, and Orient) within a sequence of unconsolidated Pleistocene and Late Cretaceous deposits. A thick glacial-lake-clay unit appears to truncate underlying deposits in three buried valleys beneath the northern shore of the North Fork. Similar glacial-lake deposits beneath eastern and east-central Long Island Sound previously were inferred to be younger than the surficial glacial deposits exposed along the northern shore of Long Island. Close similarities in thickness and upper-surface altitude between the glacial-lake-clay unit on the North Fork and the glacial-lake deposits in Long Island Sound indicate, however, that the two are correlated at least along the North Fork shore. The Matawan Group and Magothy Formation, undifferentiated, is the uppermost Cretaceous unit on the North Fork and constitutes the Magothy aquifer. The upper surface of this unit contains a series of prominent erosional features that can be traced beneath Long Island Sound and the North Fork. Northwest-trending buried ridges extend several miles offshore from areas southeast of Rocky Point and Horton Point. A promontory in the irregular, north-facing cuesta slope extends offshore from an area southwest of Mattituck Creek and James Creek. Buried valleys that trend generally southeastward beneath Long Island Sound extend onshore northeast of Hashamomuck Pond and east of Goldsmith Inlet. An undifferentiated Pleistocene confining layer, the lower confining unit, consists of apparently contiguous units of glacial-lake, marine, and nonmarine clay. This unit is more than 200 feet thick in buried valleys filled with glacial-lake clay along the northern shore, but elsewhere on the North Fork, it is generally less than 50 feet thick and presumably represents an erosional remnant of marine clay. Its upper surface is generally 75 feet or more below sea level where it overlies buried valleys, and is generally 100 feet or less below sea level in areas where marine clay has been identified. A younger unit of glacial-lake deposits, the upper confining unit, is a local confining layer and underlies a sequence of late Pleistocene moraine and outwash deposits. This unit is thickest (more than 45 feet thick) beneath two lowland areas--near Mattituck Creek and James Creek, and near Hashamomuck Pond--but pinches out close to the northern and southern shores and is locally absent in inland areas of the North Fork. Its upper-surface altitude generally rises to near sea level toward the southern shore. Freshwater in the Orient flow system is limited to the upper glacial aquifer above the top of the lower confining unit. The upper confining unit substantially impedes the downward flow of freshwater in inland parts of the Greenport flow system. Deep freshwater within the lower confining unit in the east-central part of the Cutchogue flow system probably is residual from an interval of lower sea level. The upper confining unit is absent or only a few feet thick in the west-central part of the Cutchogue flow system and does not substantially impede the downward flow of freshwater, but the lower confining unit probably im

  9. ASSESSING METHODS TO DETERMINE WHEN HYDROGEOLOGIC BARRIERS EXIST THAT RESTRICT/PROHIBIT THE TRANSPORT OF MICROBIAL CONTAMINANTS INTO THE CAPTURE ZONE OF PUBLIC WATER SYSTEM WELLS.

    EPA Science Inventory

    The product is an analysis performed by two state drinking water programs (MN and OH), testing well water for the presence or absence of fecal indicators (total coliforms, coliphages, and enterococci), to assess the effectiveness of hydrogeologic barrier methodologies being devel...

  10. Hydrogeological site characterization for the implementation of a pilot test of in-situ groundwater treatment using dual-phase slurry injection in fractured bedrock

    NASA Astrophysics Data System (ADS)

    Gheorghiu, F.; Venkatakrishnan, R.; Glazier, R.; Walata, L.; Nash, R.; Zhang, W.

    2003-04-01

    The study area is located in the Durham sub-basin of the Deep River Basin, one of the Triassic Basins that occur along the eastern seaboard of the North American Continent. The site is underlain by interbedded siltstone and sandstone sequences. Groundwater underlying portions of the site has been impacted by chlorinated volatile organic compounds. Golder conducted an initial review of potentially applicable remediation technologies and retained the Bimetallic Nanoscale Particle (BNP) technology (Wei-xian Zhang, 1997, 1999, 2000) for further evaluation at the field pilot test scale. This study presents the results of the detailed hydrogeologic studies conducted for the BNP pilot test design and implementation monitoring, and specifically looks at the changes in hydrogeological properties of the fractured bedrock aquifer as a result of injecting the BNP dual phase slurry (water and BNP solids). This study also presents the interpretation of borehole drilling, downhole televiewer logging, and hydrogeologic testing as the basis for understanding the dual phase slurry migration in the subsurface. Continuous multi-parameter monitoring was conducted during the BNP slurry injection and also was used as the basis for field estimation of fractured bedrock effective porosity. In addition, this study provides the basis for the hydrogeologic design of the full scale BNP treatment system that is expected to be more cost effective than typical pump-and-treat remedies.

  11. Hydrogeology Journal (2003) 11:217227 DOI 10.1007/s10040-002-0232-6 Abstract Natural production of the radionuclide chlo-

    E-print Network

    Zreda, Marek

    2003-01-01

    Hydrogeology Journal (2003) 11:217­227 DOI 10.1007/s10040-002-0232-6 Abstract Natural production). Natural production of this radionuclide, which has a half-life of 301,000 years, takes place in the deep be detected in many samples of groundwater. In order to be most useful in hydrologic studies, the natural

  12. The contribution of geographic information systems and remote sensing in determining priority areas for hydrogeological development, Darb el-Arbain area, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Elewa, Hossam H.; Fathy, Rafik G.; Qaddah, Atef A.

    2010-08-01

    The Darb el-Arbain study area is in the southern Western Desert of Egypt and has been attracting increasing developmental interest in the last few decades, especially since agricultural development of the southern Baris area, where the groundwater resources of the Nubian Sandstone Aquifer System (NSAS) have been utilized for the cultivation of valuable lands. Due to the proven high potential of both groundwater and land resources, determining the priority areas for sustainable hydrogeological development becomes a necessity. A geographic information system, as a platform for geospatial modeling techniques, has been built, which depends on the recently collected data about the NSAS, in addition to the published databases. Certain criteria of practical value, like depth to groundwater, hydraulic conductivity, groundwater salinity, sodium adsorption ratio, and the safe yield of wells, were selected as decisive parameters for hydrogeological prioritization. The model pinpoints areas characterized by favorable hydrogeological conditions, which could be used for future development and implementation of an artificial storage and recovery (ASR) program. The designated priority areas for hydrogeological development occur at the southern, middle southern and some localized northern parts of the Darb el-Arbain area. The newly formed Tushka Lakes represent a suitable and excellent natural source of freshwater for implementing an ASR program.

  13. 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

    SciTech Connect

    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.

  14. Hydrogeology, distribution, and volume of saline groundwater in the southern midcontinent and adjacent areas of the United States

    USGS Publications Warehouse

    Osborn, Noël I.; Smith, S. Jerrod; Seger, Christian H.

    2013-01-01

    The hydrogeology, distribution, and volume of saline water in 22 aquifers in the southern midcontinent of the United States were evaluated to provide information about saline groundwater resources that may be used to reduce dependency on freshwater resources. Those aquifers underlie six States in the southern midcontinent—Arkansas, Kansas, Louisiana, Missouri, Oklahoma, and Texas—and adjacent areas including all or parts of Alabama, Colorado, Florida, Illinois, Kentucky, Mississippi, Nebraska, New Mexico, South Dakota, Tennessee, and Wyoming and some offshore areas of the Gulf of Mexico. Saline waters of the aquifers were evaluated by defining salinity zones; digitizing data, primarily from the Regional Aquifer-System Analysis Program of the U.S. Geological Survey; and computing the volume of saline water in storage. The distribution of saline groundwater in the southern midcontinent is substantially affected by the hydrogeology and groundwater-flow systems of the aquifers. Many of the aquifers in the southern midcontinent are underlain by one or more aquifers, resulting in vertically stacked aquifers containing groundwaters of varying salinity. Saline groundwater is affected by past and present hydrogeologic conditions. Spatial variation of groundwater salinity in the southern midcontinent is controlled primarily by locations of recharge and discharge areas, groundwater-flow paths and residence time, mixing of freshwater and saline water, and interactions with aquifer rocks and sediments. The volume calculations made for the evaluated aquifers in the southern midcontinent indicate that about 39,900 million acre-feet (acre-ft) of saline water is in storage. About 21,600 million acre-ft of the water in storage is slightly to moderately saline (1,000–10,000 milligrams per liter [mg/L] dissolved solids), and about 18,300 million acre-ft is very saline (10,000–35,000 mg/L dissolved solids). The largest volumes of saline water are in the coastal lowlands (about 16,300 million acre-ft), Mississippi embayment and Texas coastal uplands (about 12,000 million acre-ft), and Great Plains (about 8,170 million acre-ft) aquifer systems. Of the 22 aquifers evaluated in this report, the Maha aquifer in the Great Plains aquifer system contains both the largest total volume of saline water (about 6,280 million acre-ft) and the largest volume of slightly to moderately saline water (about 5,150 million acre-ft).

  15. Geodatabase compilation of hydrogeologic, remote sensing, and water-budget-component data for the High Plains aquifer, 2011

    USGS Publications Warehouse

    Houston, Natalie A.; Gonzales-Bradford, Sophia L.; Flynn, Amanda T.; Qi, Sharon L.; Peterson, Steven M.; Stanton, Jennifer S.; Ryter, Derek W.; Sohl, Terry L.; Senay, Gabriel B.

    2013-01-01

    The High Plains aquifer underlies almost 112 million acres in the central United States. It is one of the largest aquifers in the Nation in terms of annual groundwater withdrawals and provides drinking water for 2.3 million people. The High Plains aquifer has gained national and international attention as a highly stressed groundwater supply primarily because it has been appreciably depleted in some areas. The U.S. Geological Survey has an active program to monitor the changes in groundwater levels for the High Plains aquifer and has documented substantial water-level changes since predevelopment: the High Plains Groundwater Availability Study is part of a series of regional groundwater availability studies conducted to evaluate the availability and sustainability of major aquifers across the Nation. The goals of the regional groundwater studies are to quantify current groundwater resources in an aquifer system, evaluate how these resources have changed over time, and provide tools to better understand a systems response to future demands and environmental stresses. The purpose of this report is to present selected data developed and synthesized for the High Plains aquifer as part of the High Plains Groundwater Availability Study. The High Plains Groundwater Availability Study includes the development of a water-budget-component analysis for the High Plains completed in 2011 and development of a groundwater-flow model for the northern High Plains aquifer. Both of these tasks require large amounts of data about the High Plains aquifer. Data pertaining to the High Plains aquifer were collected, synthesized, and then organized into digital data containers called geodatabases. There are 8 geodatabases, 1 file geodatabase and 7 personal geodatabases, that have been grouped in three categories: hydrogeologic data, remote sensing data, and water-budget-component data. The hydrogeologic data pertaining to the northern High Plains aquifer is included in three separate geodatabases: (1) base data from a groundwater-flow model; (2) hydrogeology and hydraulic properties data; and (3) groundwater-flow model data to be used as calibration targets. The remote sensing data for this study were developed by the U. S. Geological Survey Earth Resources Observation and Science Center and include historical and predicted land-use/land-cover data and actual evapotranspiration data by using remotely sensed temperature data. The water-budget-component data contains selected raster data from maps in the “Selected Approaches to Estimate Water-Budget Components of the High Plains, 1940 Through 1949 and 2000 Through 2009” report completed in 2011 (http://pubs.usgs.gov/sir/2011/5183/). Federal Geographic Data Committee compliant metadata were created for each spatial and tabular data layer in the geodatabase.

  16. Hydrogeology and water quality near a solid- and hazardous-waste landfill, Northwood, Ohio

    USGS Publications Warehouse

    De Roche, J.T.; Breen, K.J.

    1989-01-01

    Hydrogeology and water quality of ground water and selected streams were evaluated near a landfill in northwestern Ohio. The landfill is used for codisposal of solid and hazardous waste. Water-level and geologic data were collected from 36 wells and 3 surface-water sites during the period November 1983 to November 1985. Water-quality samples were collected from 18 wells and 3 surface-water sites this during this same period. The primary aquifers in the area are the Greenfield Dolomite and underlying Lockport Dolomite of Silurian age. These bedrock carbonates are overlain by two clay tills of Wisconsin age. The tills are capped by a glacial lake clay. The tills generally are saturated, but do not yield sufficient water to be considered an aquifer. Two wells in the study area yield water, in part, from discontinuous deposits of outwash sand and gravel at the lower till-bedrock interface. Regional ground-water flow is from southwest to northeast; local flow is influenced by a ground-water mound centered under the northernmost cells of the landfill. Water levels in wells penetrating refuse within the landfill and the presence of leachate seeps indicate that the refuse is saturated. Head relations among the landfill, till, and dolomite aquifer indicate a vertical component of flow downward from the landfill to the dolomite aquifer. Water levels near the landfill fluctuate as much as 14 feet per year, in contrast to fluctuations of less than 3 feet per year in wells upgradient landfill. Ground waters from wells completed in the dolomite aquifer and glacial till were found to have major-iron concentrations controlled, in large part, by reaction with calcite, dolomite, and other minerals in the aquifer. Only minor departures from equilibrium mineral saturation were noted for ground water, except in wells affected by cement/grout contamination. Molal ratios of calcuim:magnesium in ground water suggest a similar chemical evolution of waters throughout the dolomite aquifer in the study area. Stable-isotope ratios of oxygen and hydrogen indicate the source of water in the till unit and dolomite aquifer is atmospheric precipitation. Elevated levels of total dissolved solids, boron, ammonia, and iron in the leachate and in wells downgradient of the landfill may indicate mixing of ground water with leachate. Oxygen and hydrogen stable-isotope ratios were used to differentiate waters from the glacial till and dolomite aquifer. Isotope ratios also show a shift off the local mixing line for leachate and for a well just downgradient from the landfill. The shift to heavier values of o D in the well water may be indicative of leachate mixing with ground water. The effect of this mixing denoted by hydrologic, isotopic, and chemical-quality data is limited mostly to elevated levels of the common ions. Analysis did not indicate significant levels of toxic metals or organic contaminants except phenol, which was present at concentrations of from 1 to 5 micrograms per liter in six wells. Analysis of water-quality data from nearby streams suggest that surface leaching from the landfill does not significantly affect stream-water quality, but may contribute to higher level of trace metals in the streambed sediments.

  17. The analytical methods used in examining resistance of hydrogeological systems to anthropogenic pollution

    NASA Astrophysics Data System (ADS)

    Najman, Joanna; Bielewski, Jaros?aw; ?liwka, Ireneusz

    2013-04-01

    key words: gas chromatography (GC) measurement method, groundwater dating, He, SF6, F-11, F-12, Ar, Ne. In this work the method for evaluating resistance hydrogeological systems to anthropogenic pollution using environmental tracers is described. Resistance groundwater systems to anthropogenic pollution is correlated with the age of water, which can be determined by means of environmental tracers SF6, F-11, F-12 [1] and He. To correct measured values of He and SF6 the temperature of recharge and the excess air is needed and can be determined by measuring Ne and Ar concentrations in groundwater. This paper describes three measurement GC systems to determine the concentrations of greenhouse gases: sulfur hexafluoride (SF6) and chlorofluorocarbons F-11, F-12 [2], the noble gases neon (Ne), argon (Ar) [3] and helium (He) [4] in groundwater. The first system for measurements of the concentration of SF6, F-11 and F-12 consists of a gas chromatograph, type N504 is supplied with nitrogen carrier gas with a purity of 6.0. It is equipped with two packed columns K1 and K2 running at 60°C with the use of the "back-flush" column switching and electron capture detector (ECD) operating at 300°C. Second system for measuring the concentration of the noble gases argon and neon, is composed of a dual Shimadzu gas chromatograph. It is equipped with two columns K4 and K5 operating at 30°C, thermalconductivity detector (TCD) for analysis of argon and helium detector with pulse discharge (PDHID) for analysis of neon. This chromatograph is powered by helium carrier gas 6.0. The third system measures the concentration of helium, consists of a gas chromatograph equipped with a TCD detector and three packed columns filled with molecular sieve type 5A and activated carbon. The carrier gas in this system is argon 6.0. Detection limit, LOD for each measurement systems for the tested compounds are: 0,06 fmol/L for SF6, 15 fmol/L for F-11, 10 fmol/L for F-12, 1,9•10-8 cm3STP/cm3 for Ne, 3,1•10-6 cm3STP/cm3 for Ar and 1,2•10-8cm3STP/gH2O for He. Work performed within the strategic research project "Technologies supporting the development of safe nuclear power" financed by the National Centre for Research and Development (NCBiR). Research Task "Development of methods to assure nuclear safety and radiation protection for current and future needs of nuclear power plants", contract No. SP/J/6/143339/11. This work was also supported by grant No. N N525 3488 38 from the Polish National Science Centre. [1] I. ?liwka, et al., Long-Term Measurements of CFCs and SF6 Concentration in Air, Polish J. of Eviron. Stud. Vol. 19, No. 4, 811-815, 2010. [2] I. ?liwka, et al., Headspace Extraction Method for Simultaneus Determination of SF6, CCl3F2, CCl2F2 and CCl2FCClF2 in Water, Chem. Anal. (Warsaw) 49,535, 2004. [3] P. Mochalski, Chromatographic method for the determination of Ar, Ne and N2 in water, Ph.D. thesis, Institute of Nuclear Physics Polish Academy of Sciences in Krakow, 2003 (in polish). [4] J. Najman, Development of chromatographic measurement method of helium concentration in groundwater for the purpose of dating in the hydrological issues, Ph.D. thesis, Institute of Nuclear Physics Polish Academy of Sciences in Krakow, 2008, http://www.ifj.edu.pl/SD/rozprawy_dr/rozpr_Najman.pdf?lang=pl (in polish).

  18. Hydrogeological response to tele-seismic events with underground water level precision monitoring data

    NASA Astrophysics Data System (ADS)

    Gorbunova, Ella; Vinogradov, Evgeny; Besedina, Alina; Kabychenko, Nikolay; Svintsov, Igor

    2015-04-01

    Underground water level precision monitoring has been being carried out in the IDG RAS experimental area "Mikhnevo" in step with barometric pressure measuring since February of 2008. Seismic events registration is being realized with small aperture seismic array "Mikhnevo" and STS-2 seismometer. Complex processing of original hydrological and seismic data allows to mark out hydrological responses to large earthquakes (Mw>7.5) seismic waves propagation throw aseismic region - central area of Russian Plate. GPO "Mikhnevo" is located within South part of Moscow artesian basin in the North-East part of Prioksko-Terrasny biosphere reserve out of intensive anthropogenic impact zone. Wellbore unseals index aquifer in the interval of 91-115 m. An aquifer is characterized with season level variations. Water containing rocks are presented with nonuniform fractured limestones. In IDG RAS step-by-step methodic of experimental data handling was devised. First preliminary comparison of 1 Hz frequency seismic and hydrological data is being carried out for hydrogeological response to large earthquakes (Mw>7.5) seismic waves propagation marking out. On basis of these data main types and parameters of waves registered in seismic and hydrological data are being identified and representative periods for geological medium response to tele-seismic events analysis are being selected. In the area of GPO "Mikhnevo" we traced geological response to disastrous earthquakes that took place 02/27/2011 near Central Chile Coast and 03/11/11 near Honshu Island east coast that is presented being smoothed in underground water level. Tele-seismic events differs in intensity, signal duration and post-seismic effect. Significant water level harmonic oscillations are coupled with surface and S-waves arrival, where vertical component prevails First hydrological responses were registered in the time of S-wave propagation 28 minutes after Honshu earthquake beginning and 39 minutes after Chile earthquake beginning with low-grade amplitude 19 mm and 5 mm accordingly. Surface wave propagation presented on a plot is coupled with water level variations with peak amplitude 24 mm and 15.8 mm accordingly. On the whole hydrological response corresponds to ground displacement. After disastrous earthquakes post-seismic underground water level response was registered. 2.5 hours after Chile earthquake 4 mm stepwise level increase was registered that is believed to be connected to next wave train arrival. Over a 6 hours after Honshu earthquake 12-13 mm level rise is traced and than smooth level fall is registered 6-8 mm less than initial level. Before earthquakes water level was stable that is why we suppose that seismic waves propagation impact did led to traced post-seismic effects. Water level and ground velocity precision monitoring results were used for background parameters observation and signal distortion periods marking out. This periods can be connected to geological medium response to disastrous earthquakes. Post-seismic underground water level variations were observed 02/27/2010 and 03/11/2011 that is supposed to be evidence of probable altering of filtration links structure on microlevel.

  19. Groundwater denitrification in two agricultural river catchments: influence of hydro-geological setting and aquifer geochemistry

    NASA Astrophysics Data System (ADS)

    McAleer, Eoin; Mellander, Per-Erik; Coxon, Catherine; Richards, Karl G.; Jahangir, Mohammad M. R.

    2015-04-01

    Identifying subsurface environments with a natural capacity for denitrification is important for improving agricultural management. At the catchment scale, a complex hierarchy of landscape, hydro-geological and physico-chemical characteristics combine to affect the distribution of groundwater nitrate (NO3-). This study was conducted along four instrumented hillslopes in two ca. 10km2 agricultural river catchments in Ireland, one dominated by arable and one by grassland agriculture. Both catchments are characterised by well drained soils, but have differing aquifer characteristics. The arable catchment is underlain by weathered Ordovician slate bedrock which is extensively fractured with depth. The grassland catchment is characterised by Devonian sandstone bedrock, exhibiting both lateral (from upslope to near stream) and vertical variations in permeability along each hillslope. The capacity for groundwater denitrification was assessed by examining the concentration and distribution patterns of N species (total nitrogen, nitrate, nitrite, ammonium), dissolved organic carbon (DOC), dissolved oxygen (DO) and redox potential (Eh) in monthly samples from shallow and deep groundwater piezometers (n=37). Additionally, the gaseous products of denitrification: nitrous oxide (N2O) and excess dinitrogen (excess N2) were measured seasonally using gas chromatography and membrane inlet mass spectroscopy, respectively. The slate catchment was characterised by uniformity, both laterally and vertically, in aquifer geochemistry and gaseous denitrification products. The four year spatial mean groundwater NO3--N concentration was 6.89 mg/l and exhibited low spatial and temporal variability (temporal SD: 1.19 mg/l, spatial SD: 1.185 mg/l). Elevated DO concentrations (mean: 9.75 mg/l) and positive Eh (mean: +176.5mV) at all sample horizons indicated a setting with little denitrification potential. This non-reducing environment was reflected in a low accumulation of denitrification products (excess N2 mean: 1.57 mg/l, N2O mean: 1.61µg/l). Groundwater in the sandstone catchment had a comparable mean NO3--N concentration to that of the slate site (6.24mg/l) and while temporal variation was low (SD: 0.9 mg/l), spatial variation was substantially greater (SD: 3.63 mg/l). The accumulation of denitrification products in the sandstone catchment showed a large contrast to that of the slate with excess N2 ranging from 0.16-8.77 mg/l and N2O from 0.07-66.42 µg/l. Mean dissolved oxygen concentration and redox potential were 5.6mg/l and 67.5mV respectively. The near stream zones in particular were marked by favourable denitrifying conditions: hydraulic conductivity (<2m/day), Eh (<50mV) and DO (<5mg/l). Winter recharge had a diluting effect, increasing the concentration of DO and Eh with a concurrent decrease in excess N2 and N2O. The evolution of groundwater geochemistry along a subsurface flow path is a function of residence time. While both catchments are characterised as permeable, the slate catchment exhibits greater hydraulic conductivity values, particularly at depth, with groundwater geochemistry in all horizons reflective of recently recharged water. The deeper groundwater pathways and near stream zones in the sandstone catchment have a lower hydraulic conductivity. As such, dissolved oxygen and redox gradients occur with depth, causing the development of NO3- reducing zones.

  20. Hydrogeology and ground-water quality of Brunswick County, North Carolina

    USGS Publications Warehouse

    Harden, Stephen L.; Fine, Jason M.; Spruill, Timothy B.

    2003-01-01

    Brunswick County is the southernmost coastal county in North Carolina and lies in the southeastern part of the Coastal Plain physiographic province. In this report, geologic, hydrologic, and chemical data were used to investigate and delineate the hydro-geologic framework and ground-water quality of Brunswick County. The major aquifers and their associated confining units delineated in the Brunswick County study area include, from youngest to oldest, the surficial, Castle Hayne, Peedee, Black Creek, upper Cape Fear, and lower Cape Fear aquifers. All of these aquifers, with the exception of the Castle Hayne aquifer, are located throughout Brunswick County. The Castle Hayne aquifer extends across only the southeastern part of the county. Based on available data, the Castle Hayne and Peedee confining units are missing in some areas of Brunswick County, which allows direct hydraulic contact between the surficial aquifer and underlying Castle Hayne or Peedee aquifers. The confining units for the Black Creek, upper Cape Fear, and lower Cape Fear aquifers appear to be continuous throughout Brunswick County. In examining the conceptual hydrologic system for Brunswick County, a generalized water budget was developed to better understand the natural processes, including precipitation, evapotranspiration, and stream runoff, that influence ground-water recharge to the shallow aquifer system in the county. In the generalized water budget, an estimated 11 inches per year of the average annual precipitation of 55 inches per year in Brunswick County is estimated to infiltrate and recharge the shallow aquifer system. Of the 11 inches per year that recharges the shallow system, about 1 inch per year is estimated to recharge the deeper aquifer system. The surficial aquifer in Brunswick County is an important source of water for domestic supply and irrigation. The Castle Hayne aquifer is the most productive aquifer and serves as the principal ground-water source of municipal supply for the county. The upper part of the Peedee aquifer is an important source of ground-water supply for domestic and commercial use. Ground water in the lower part of the Peedee aquifer and the underlying aquifers is brackish and is not known to be used as a source of supply in Brunswick County. Most of the precipitation that recharges the surficial aquifer is discharged to local streams that drain into the Waccamaw River, Cape Fear River, and Atlantic Ocean. Recharge to the Castle Hayne aquifer occurs primarily from the surficial aquifer. Recharge to the Peedee aquifer occurs primarily from the surficial and Castle Hayne aquifers, with some upward leakage of water also occurring from the underlying Black Creek aquifer. Discharge from the Castle Hayne and Peedee aquifers occurs to local streams, the Cape Fear River, and the Atlantic Ocean. Evaluation of water-level data for the period January 1970 through May 2002 indicated no apparent long-term temporal trends in water levels in the surficial and Castle Hayne aquifers and in the upper part of the Peedee aquifer. The most significant water-level trends were noted for wells tapping the lower part of the Peedee aquifer and tapping the Black Creek aquifer where water levels have declined as much as 41 and 37 feet, respectively. These ground-water-level declines are attributed to regional ground-water pumping in areas outside of Brunswick County. Water-level data for Brunswick County wells tapping the upper Cape Fear and lower Cape Fear aquifers tend to fluctuate within a fairly uniform range with no apparent temporal trend noted. Analysis of vertical hydraulic gradients during this same period primarily indicate downward flow of ground water within and among the surficial, Castle Hayne, and Peedee aquifers. The vertical flow of ground water in the Black Creek aquifer is upward into the overlying Peedee aquifer. Upward flow also is noted for the upper and lower Cape Fear aquifers. Historic and recent analytic

  1. Hydrogeologic uncertainties and policy implications: The Water Consumer Protection Act of Tucson, Arizona, USA

    NASA Astrophysics Data System (ADS)

    Wilson, L. G.; Matlock, W. G.; Jacobs, K. L.

    The 1995 Water Consumer Protection Act of Tucson, Arizona, USA (hereafter known as the Act) was passed following complaints from Tucson Water customers receiving treated Central Arizona Project (CAP) water. Consequences of the Act demonstrate the uncertainties and difficulties that arise when the public is asked to vote on a highly technical issue. The recharge requirements of the Act neglect hydrogeological uncertainties because of confusion between "infiltration" and "recharge." Thus, the Act implies that infiltration in stream channels along the Central Wellfield will promote recharge in the Central Wellfield. In fact, permeability differences between channel alluvium and underlying basin-fill deposits may lead to subjacent outflow. Additionally, even if recharge of Colorado River water occurs in the Central Wellfield, groundwater will become gradually salinized. The Act's restrictions on the use of CAP water affect the four regulatory mechanisms in Arizona's 1980 Groundwater Code as they relate to the Tucson Active Management Area: (a) supply augmentation; (b) requirements for groundwater withdrawals and permitting; (c) Management Plan requirements, particularly mandatory conservation and water-quality issues; and (d) the requirement that all new subdivisions use renewable water supplies in lieu of groundwater. Political fallout includes disruption of normal governmental activities because of the demands in implementing the Act. Résumé La loi de 1995 sur la protection des consommateurs d'eau de Tucson (Arizona, États-Unis) a été promulguée à la suite des réclamations des consommateurs d'eau de Tucson alimentés en eau traitée à partir à la station centrale d'Arizona (CAP). Les conséquences de cette loi montrent les incertitudes et les difficultés qui apparaissent lorsque le public est appeléà voter sur un problème très technique. Les exigences de la loi en matière de recharge négligent les incertitudes hydrogéologiques du fait de la confusion entre "infiltration" et "recharge". C'est ainsi que la loi laisse entendre que l'infiltration à partir des lits de rivières le long du champ captant central favorise la recharge de cette zone. En réalité, les différences de perméabilité entre les alluvions du lit et les dépôts sous-jacents remplissant le bassin peuvent provoquer un écoulement sous-jacent. En outre, même si une recharge par l'eau de la rivière Colorado se produit dans cette zone, la nappe sera progressivement salifiée. Les restrictions imposées par la loi quant à l'utilisation de l'eau de la station centrale d'Arizona affectent les quatre outils réglementaires du Code des eaux souterraines de l'Arizona de 1980, en ce qu'ils concernent la zone de gestion active de Tucson: (a) l'augmentation de l'approvisionnement (b) les conditions requises pour les prélèvements d'eau souterraine et les autorisations; (c) les conditions requises pour le plan de gestion, en particulier la pérennité du concessionnaire et les résultats en matière de qualité de l'eau et (d) la condition que tous les nouveaux districts aient recours à des ressources en eau renouvelables à la place de l'eau souterraine. Les demandes concernant la mise en oeuvre de la loi ont conduit jusqu'à l'arrêt des activités normales des instances politiques. Resumen El Acta de Protección de los Usuarios de Agua de Tucson, Arizona (EE.UU.) de 1995 (el Acta) se aprobó a raíz de las quejas de los usuarios de agua de Tucson que recibían agua tratada por el Proyecto de Arizona Central (CAP). Las consecuencias del Acta demuestran las incertidumbres y dificultades que se producen cuando se le pide al público que vote sobre temas muy técnicos. Los requerimientos de recarga del Acta desprecian incertidumbres hidrogeológicas al confundir entre "infiltración" y "recarga". Así, el Acta dice que la infiltración en los canales de los arroyos a lo largo del Campo de Producción Central aumentará la recarga a dicho campo. De hecho, la diferencia de permeabilidad e

  2. Numerical analysis of the hydrogeologic controls in a layered coastal aquifer system, Oahu, Hawaii, USA

    NASA Astrophysics Data System (ADS)

    Oki, Delwyn S.; Souza, William R.; Bolke, Edward L.; Bauer, Glenn R.

    The coastal aquifer system of southern Oahu, Hawaii, USA, consists of highly permeable volcanic aquifers overlain by weathered volcanic rocks and interbedded marine and terrestrial sediments of both high and low permeability. The weathered volcanic rocks and sediments are collectively known as caprock, because they impede the free discharge of groundwater from the underlying volcanic aquifers. A cross-sectional groundwater flow and transport model was used to evaluate the hydrogeologic controls on the regional flow system in southwestern Oahu. Controls considered were: (a) overall caprock hydraulic conductivity; and (b) stratigraphic variations of hydraulic conductivity in the caprock. Within the caprock, variations in hydraulic conductivity, caused by stratigraphy or discontinuities of the stratigraphic units, are a major control on the direction of groundwater flow and the distribution of water levels and salinity. Results of cross-sectional modeling confirm the general groundwater flow pattern that would be expected in a layered coastal system. Groundwater flow is: (a) predominantly upward in the low-permeability sedimentary units; and (b) predominantly horizontal in the high-permeability sedimentary units. Résumé Le système aquifère littoral du sud d'Oahu (Hawaii, États-Unis) est constitué par des aquifères de terrains volcaniques très perméables, recouverts par des roches volcaniques altérées, et interstratifiés avec des sédiments marins et continentaux de perméabilité aussi bien forte que faible. Les roches volcaniques altérées et les sédiments sont globalement considérés comme une couverture, parce qu'ils s'opposent à l'écoulement de l'eau souterraine provenant des aquifères volcaniques sous-jacents. Les contrôles hydrogéologiques sur le système aquifère régional du sud-ouest d'Oahu ont étéévaluées au moyen d'un modèle d'écoulement et de transport sur une section transversale. Ces contrôles prennent en compte la conductivité hydraulique de la couverture dans son ensemble et les variations de la conductivité hydraulique liées à la stratigraphie de la couverture. A l'intérieur de la couverture, les variations de la conductivité hydraulique, dues à la stratigraphie ou à des discontinuités entre les unités stratigraphiques, sont le contrôle principal de la direction d'écoulement et de la répartition des niveaux et de la salinité de l'eau. La modélisation sur une section transversale a donné des résultats qui confirment l'organisation générale des directions d'écoulement, telle qu'elle pouvait être envisagée dans un aquifère littoral multicouche. L'écoulement souterrain est essentiellement vertical vers le haut dans les unités sédimentaires à faible perméabilité, et essentiellement horizontal dans les unités sédimentaires à forte perméabilité. Resumen El sistema acuífero costero de la zona sur de Oahu, en Hawaii, está formado por acuíferos volcánicos de alta permeabilidad, subyacentes a rocas volcánicas alteradas, con inclusiones de sedimentos marinos y terrestres, tanto de alta como de baja permeabilidad. Al conjunto de rocas volcánicas alteradas y sedimentos se le conoce por "tapón de roca", ya que impide la descarga libre de las aguas subterráneas del acuífero volcánico subyacente. Se usó un modelo de flujo de agua subterránea y transporte de solutos en sección vertical para evaluar los aspectos hidrogeológicos que controlan el flujo regional en la zona sudoeste de Oahu. Se consideraron: (a) la conductividad hidráulica global del tapón y (b) las variaciones estratigráficas de la conductividad hidráulica. En el tapón de roca, las variaciones de la conductividad hidráulica, causadas por la estratigrafía o por discontinuidades en las unidades estratigráficas, son las que controlan la dirección del flujo subterráneo y la distribución de niveles piezométricos y salinidad. Los resultados del modelo en sección transversal confirman la distribución del flujo subterráneo que cabría esperar en un sistema costero estrat

  3. Hydrogeology and ground-water availability in the carbonate aquifer system of Frederick County, Virginia

    USGS Publications Warehouse

    Harlow,, George E., Jr.; Orndorff, Randall C.; Nelms, David L.; Weary, David J.; Moberg, Roger M.

    2005-01-01

    The carbonate aquifer system of the northern Shenandoah Valley provides an important water supply to local communities, including Frederick County, Va., which depends on ground water as a source of water supply. The county and surrounding area are undergoing increased urbanization, and increased demands on the carbonate aquifer system are expected. A study was conducted between October 2000 and March 2004 by the U.S. Geological Survey (USGS), in cooperation with the County of Frederick, Va., to describe the hydrogeology and ground-water availability in the carbonate aquifer system underlying the county. The study area encompasses about 25 percent (105 square miles) of the county that is underlain by carbonate bedrock. The carbonate aquifer system of Frederick County is in the Shenandoah Valley region of the Valley and Ridge Physiographic Province. Approximately 10,000 feet of folded and fractured Middle Cambrian to Upper Ordovician sedimentary rocks are exposed and are overlain by Pleistocene (?) and Holocene surficial deposits. All geologic units in the study area are considered to be aquifers. The geologic units are generally unconfined, fractured-rock aquifers that are recharged by precipitation and discharge locally to streams and springs, and by evapotranspiration. Stream density in the carbonate study area is less than in the remainder of the county, which is underlain by siliciclastic rock units. Most streams flow normal to strike (from the northwest towards the southeast) across the study area. These streams are characterized by shallow incisement and are usually limited to a single stream channel. In the southern third of the study area, streams flow parallel to strike (from the northeast towards the southwest) towards the deeply intrenched Cedar Creek. Springs are commonly located at the start of flows for all streams in the carbonate study area, and spring discharges are often a large portion of the streamflow (especially during drought conditions). The general direction of ground-water flow is from the hills in the west of the study area into and across the carbonate valley. A ground-water divide may occur north of Round Hill in the vicinity of the Apple Pie Ridge fault where the North Mountain fault zone cuts out the resistant Silurian and Devonian sandstone units and results in surface drainage from the carbonate rocks toward the west and out of the carbonate valley. Estimates of effective ground-water recharge for 2001-02 range from 5.8 to 6.2 inches in the Cedar Creek Basin, with base flow accounting for between 60 and 64 percent of streamflow, and from 3.2 to 3.8 inches in the Opequon Creek Basin, with base flow accounting for between 86 and 92 percent of streamflow. Water budgets calculated for 2001, a year of below-normal precipitation (33.1 inches), and 2002, a year of above-normal precipitation (41.2 inches), include a streamflow of 9.0 inches in 2001 and 9.2 inches in 2002 in Cedar Creek. Evapotranspiration ranged from 25.9 to 30.7 inches, and ground-water storage decreased 1.8 inches in 2001 and increased 1.3 inches in 2002. Streamflow was 3.7 inches in 2001 and 2002 in Opequon Creek. Evapotranspiration ranged from 29.8 to 37.5 inches, and ground-water storage decreased 0.4 inch in 2001 and did not change in 2002.

  4. Impact of Acid Mine Drainage on the hydrogeological system at Sia, Cyprus

    NASA Astrophysics Data System (ADS)

    Ng, Stephen; Malpas, John

    2013-04-01

    Discontinued mining of the volcanogenic massive sulphide ore bodies of Cyprus has left significant environmental concerns including Acid Mine Drainage. Remnant sulphide ore and tailings in waste dumps react with oxygenated rainwater to produce sulphuric acid, a process which is multiplied when metal-loving acidophilic bacteria are present. Given that Cyprus has a Mediterranean climate, characterized by its warm and dry summers and cool and wet winters, the low pH effluent with high levels of trace elements, particularly metals, is leached out of the waste tips particularly during the wet season. The Sia site includes an open mine-pit lake, waste rock and tailings dumps, a river leading to a downstream dam-lake, and a localised groundwater system. The study intends to: identify the point source and nature of contamination; analyze the mechanism and results of local acid generation; and understand how the hydrogeological system responds to seasonal variations. During two sampling campaigns, in the wet and dry seasons of 2011, water samples were collected from the mine pit lake, from upstream of the adjacent river down to the dam catchment, and from various boreholes close to the sulphide mine. The concentration of ions in waters varies between wet and dry seasons but, in both, relative amounts are directly related to pH. In the mine-pit lake, Fe, Mn, Mg, Cu, Pb, Zn, Ni, Co and Cd are found in higher concentrations in the dry season, as a result of substantial evaporation of water. The Sia River runs continuously in the wet season, and waters collected close to the waste tips have pH as low as 2.5 and higher concentrations of Al, Cu, Fe and Zn. Further downstream there is a significant decrease in trace metal contents with a concomitant rise of pH. Al and Fe dominate total cation content when pH is lower than 4. Al is derived from the weathering of clay minerals, especially during the wet season. Fe is derived from the oxidation of pyrite. Once pH's exceed 4, a white precipitate of gibbsite (Al(OH)3) settles to the stream bed removing Al from the water. This is finely laminated together with orange-brown layers of similarly precipitated Fe(OH)3. During the dry season the Sia River dries up and the mine-pit lake is greatly reduced in surface area leading to the crystallisation of a variety of multi-coloured salts, which form on the muddy substrate through capillary action. These include large amounts of gypsum and hexahydrite, and lesser amounts of chalcanthite, jarosite, wupatkiite, halotrichite, malachite, etc. These are ephemeral in nature being quickly dissolved by early rains of the wet season that, in the stream waters, produces short-lived toxic concentrations of metals. Groundwaters sampled directly at the mine site show the influence of drainage from the waste tips. Elsewhere, apart from sporadic high Boron concentrations, there is no evidence of contamination from the mine workings. The origin of Boron is a problem that arises at a number of sites throughout Cyprus, especially on the Mesaoria Plain and in the Troodos Complex.

  5. Development of a summer field-based hydrogeology research experience for undergraduates

    NASA Astrophysics Data System (ADS)

    Singha, K.

    2011-12-01

    A critical problem in motivating and training the next generation of environmental scientists is providing them with an integrated scientific experience that fosters a depth of understanding and helps them build a network of colleagues for their future. As the education part of an NSF-funded CAREER proposal, I have developed a three-week summer research experience for undergraduate students that links their classroom education with field campaigns aiming to make partial differential equations come "alive" in a practical, applied setting focused on hydrogeologic processes. This course has been offered to freshman- to junior-level undergraduate students from Penn State and also the three co-operating Historically Black Universities (HBUs)--Jackson State University, Fort Valley State University, and Elizabeth City State University-since 2009. Broad learning objectives include applying their knowledge of mathematics, science, and engineering to flow and transport processes in the field and communicating science effectively in poster and oral format. In conjunction with ongoing research about solute transport, students collected field data in the Shale Hills Critical Zone Observatory in Central Pennsylvania, including slug and pumping tests, ground-penetrating radar, electrical resistivity imaging, wireline logging, and optical televiewers, among other instruments. Students conducted tracer tests, where conservative solutes are introduced into a local stream and monitored. Students also constructed numerical models using COMSOL Multiphysics, a research-grade code that can be used to model any physical system; with COMSOL, students create models without needing to be trained in computer coding. With guidance, students built basic models of fluid flow and transport to visualize how heterogeneity of hydraulic and transport properties or variations in forcing functions impact their results. The development of numerical models promoted confidence in predicting flow and transport in the field. For most of the students, this was their first opportunity to work in the field, and also their first time working with numerical models. The capstone of the class is a final poster presentation with a short oral introduction. Most students commented that this session, attended by graduate students and faculty at Penn State, was an inspiring experience. Feedback for the course has been uniformly positive, with one student noting on post-course feedback that "The best way of learning is by doing it". One benefit of CAREER funding is the ability to develop innovative pedagogy and bring it into the classroom with ease, due to financial support. In my case, the diverse backgrounds of the students in the course has required all of the students to work with students from other demographics, and that alone has been a valuable experience. One difficulty will be continuing this field program once the grant has ended; numerous students commented that they felt lucky to be part of the program during its 5-year existence and lamented that other students wouldn't have the same opportunity. The students' data and model runs will be published and used for my long-term research agenda in discriminating transport processes in situ, as well, making a positive feedback loop between research and education.

  6. Fractured-aquifer hydrogeology from geophysical logs; the passaic formation, New Jersey

    USGS Publications Warehouse

    Morin, R.H.; Carleton, G.B.; Poirier, S.

    1997-01-01

    The Passaic Formation consists of gradational sequences of mudstone, siltstone, and sandstone, and is a principal aquifer in central New Jersey. Ground-water flow is primarily controlled by fractures interspersed throughout these sedimentary rocks and characterizing these fractures in terms of type, orientation, spatial distribution, frequency, and transmissivity is fundamental towards understanding local fluid-transport processes. To obtain this information, a comprehensive suite of geophysical logs was collected in 10 wells roughly 46 m in depth and located within a .05 km2 area in Hopewell Township, New Jersey. A seemingly complex, heterogeneous network of fractures identified with an acoustic televiewer was statistically reduced to two principal subsets corresponding to two distinct fracture types: (1) bedding-plane partings and (2) high-angle fractures. Bedding-plane partings are the most numerous and have an average strike of N84??W and dip of 20??N. The high-angle fractures are oriented subparallel to these features, with an average strike of N79??E and dip of 71??S, making the two fracture types roughly orthogonal. Their intersections form linear features that also retain this approximately east-west strike. Inspection of fluid temperature and conductance logs in conjunction with flowmeter measurements obtained during pumping allows the transmissive fractures to be distinguished from the general fracture population. These results show that, within the resolution capabilities of the logging tools, approximately 51 (or 18 percent) of the 280 total fractures are water producing. The bedding-plane partings exhibit transmissivities that average roughly 5 m2/day and that generally diminish in magnitude and frequency with depth. The high-angle fractures have average transmissivities that are about half those of the bedding-plane partings and show no apparent dependence upon depth. The geophysical logging results allow us to infer a distinct hydrogeologic structure within this aquifer that is defined by fracture type and orientation. Fluid flow near the surface is controlled primarily by the highly transmissive, subhorizontal bedding-plane partings. As depth increases, the high-angle fractures apparently become more dominant hydrologically.The Passaic Formation consists of gradational sequences of mudstone, siltstone, and sandstone, and is a principal aquifer in central New Jersey. Ground-water flow is primarily controlled by fractures interspersed throughout these sedimentary rocks and characterizing these fractures in terms of type, orientation, spatial distribution, frequency, and transmissivity is fundamental towards understanding local fluid-transport processes. To obtain this information, a comprehensive suite of geophysical logs was collected in 10 wells roughly 46 m in depth and located within a .05 km2 area in Hopewell Township, New Jersey. A seemingly complex, heterogeneous network of fractures identified with an acoustic televiewer was statistically reduced to two principal subsets corresponding to two distinct fracture types: (1) bedding-plane partings and (2) high-angle fractures. Bedding-plane partings are the most numerous and have an average strike of N84?? W and dip of 20?? N. The high-angle fractures are oriented subparallel to these features, with an average strike of N79?? E and dip of 71?? S, making the two fracture types roughly orthogonal. Their intersections form linear features that also retain this approximately east-west strike. Inspection of fluid temperature and conductance logs in conjunction with flowmeter measurements obtained during pumping allows the transmissive fractures to be distinguished from the general fracture population. These results show that, within the resolution capabilities of the logging tools, approximately 51 (or 18 percent) of the 280 total fractures are water producing. The bedding-plane partings exhibit transmissivities that average roughly 5 m2/day and that generally dimi

  7. Assessment of the hydrogeology and water quality in a near-shore well field, Sarasota, Florida

    USGS Publications Warehouse

    Broska, J.C.; Knochenmus, L.A.

    1996-01-01

    The city of Sarasota, Florida, operates a downtown well field that pumps mineralized water from ground water sources to supply a reverse osmosis plant. Because of the close proximity of the well field to Sarasota Bay and the high sulfate and chloride concentrations of ground-water supplies, a growing concern exists about the possibility of lateral movement of saltwater in a landward direction (intrusion) and vertical movement of relict sea water (upconing). In 1992, the U.S. Geological Survey began a 3-year study to evaluate the hydraulic characteristics and water quality of ground-water resources within the downtown well field and the surrounding 235-square-mile study area. Delineation of the hydrogeology of the study area was based on water- quality data, aquifer test data, and extensive borehole geophysical surveys (including gamma, caliper, temperature, electrical resistivity, and flow meter logs) from the six existing production wells and from a corehole drilled as part of the study, as well as from published and unpublished reports on file at the U.S. Geological Survey, the Southwest Florida Water Management District, and consultant's reports. Water-quality data were examined for spatial and temporal trends that might relate to the mechanism for observed water-quality changes. Water quality in the study area appears to be dependent upon several mechanisms, including upconing of higher salinity water from deeper zones within the aquifer system, interbore-hole flow between zones of varying water quality through improperly cased and corroded wells, migration of highly mineralized waters through structural deformities, and the presence of unflushed relict seawater. A numerical ground-water flow model was developed as an interpretative tool where field-derived hydrologic characteristics could be tested. The conceptual model consisted of seven layers to represent the multilayered aquifer systems underlying the study area. Particle tracking was utilized to delineate the travel path of water as it enters the model area under a set of given conditions. Within the model area, simulated flow in the intermediate aquifer system originates primarily from the northwestern boundary. Simulated flow in the Upper Floridan aquifer originates in lower model layers (deeper flow zones) and ultimately can be traced to the southeastern and northwestern boundaries. Volumetric budgets calculated from numerical simulation of a hypothetical well field indicate that the area of contribution to the well field changes seasonally. Although ground-water flow patterns change with wet and dry seasons, most water enters the well-field flow system through lower parts of the Upper Floridan aquifer from a southeastern direction. Moreover, particle tracking indicated that ground-water flow paths with strictly lateral pathlines in model layers correspond to the intermediate aquifer system, whereas particles traced through model layers corresponding to the Upper Floridan aquifer had components of vertical and lateral flow.

  8. Hydrogeology and water quality of the Nutmeg Valley area, Wolcott and Waterbury, Connecticut

    USGS Publications Warehouse

    Mullaney, J.R.; Mondazzi, R.A.; Stone, J.R.

    1999-01-01

    Hydrogeologic investigations in an industrial area in Wolcott and Waterbury, Connecticut, have provided information on the geology, ground-water flow, and water quality of the area. Ground-water contamination by volatile organic compounds was discovered in the 1980?s in the Nutmeg Valley area, where approximately 43 industries and 25 residences use ground water for industrial and domestic supply. Unconsolidated surficial deposits, including glacial stratified deposits and till, are more than 85 feet thick and are interconnected with the underlying bedrock. The horizontal hydraulic conductivity of the stratified deposits ranges from 0.8 to 21 feet per day. Water in the surficial aquifer generally flows toward discharge points along Old Tannery Brook and the Mad River. Water in the bedrock aquifer flows through low-angle unroofing joints, high-angle fractures, and foliation-parallel fractures. Most high-angle water-bearing fractures strike north with an easterly dip. Most of the water pumped from bedrock wells in the study area comes from shallow fractures that are probably in hydraulic connection with the surficial aquifer. Short-circuit flow between fracture zones in wells is a likely pathway for contaminant transport. During periods of low streamflow, only a small amount of ground water discharges directly to Old Tannery Brook or to the Mad River. The amount of discharge is on the same order of magnitude as the estimated ground-water withdrawals. In northern parts of the valley bottom within the study area, downward vertical hydraulic gradients were present between wells in the surficial and bedrock aquifers. In southern parts of the valley, however, vertical gradients were upward from the bedrock to the surficial aquifer. Vertical gradients can change seasonally in response to different amounts of ground-water recharge and to stresses caused by ground-water withdrawals, which can in turn facilitate the spread of contamination. Vapor-diffusion samplers were installed in streambeds to identify zones where water containing volatile organic compounds was discharging to streams in the study area. Three areas with high vapor concentrations of trichloroethene and tetrachloroethene were identified. Concentrations of trichloroethene as high as 30,000 parts per billion by volume were detected. Three of 44 wells sampled contained concentrations of volatile organic compounds, including trichloroethene and tetrachloroethene, above primary drinking water standards. Based on the findings of this and previous investigations, water in the bedrock aquifer in the southern part of the study area is likely to contain trichloroethene, tetrachloroethene, and 1,1,1-trichloroethane. Volatile organic compounds also were detected in stream samples from the downstream end of Old Tannery Brook and the Mad River. Concentrations of major ions and trace elements (with one exception) did not exceed primary drinking water standards in any ground-water or surface-water samples collected. Ground-water samples collected downgradient from the Waterbury North End Disposal Area contained ethyl ether, chlorobenzene, and elevated concentrations of dissolved solids, similar to samples of landfill leachate and groundwater samples collected from springs and wells adjacent to the landfill.

  9. Geometrical and hydrogeological impact on the behaviour of deep-seated rock slides during reservoir impoundment

    NASA Astrophysics Data System (ADS)

    Lechner, Heidrun; Zangerl, Christian

    2015-04-01

    Given that there are still uncertainties regarding the deformation and failure mechanisms of deep-seated rock slides this study concentrates on key factors that influence the behaviour of rock slides in the surrounding of reservoirs. The focus is placed on the slope geometry, hydrogeology and kinematics. Based on numerous generic rock slide models the impacts of the (i) rock slide geometry, (ii) reservoir impoundment and level fluctuations, (iii) seepage and buoyancy forces and (iv) hydraulic conductivity of the rock slide mass and the basal shear zone are examined using limit equilibrium approaches. The geometry of many deep-seated rock slides in metamorphic rocks is often influenced by geological structures, e.g. fault zones, joints, foliation, bedding planes and others. With downslope displacement the rock slide undergoes a change in shape. Several observed rock slides in an advanced stage show a convex, bulge-like topography at the foot of the slope and a concave topography in the middle to upper part. Especially, the situation of the slope toe plays an important role for stability. A potentially critical situation can result from a partially submerged flat slope toe because the uplift due to water pressure destabilizes the rock slide. Furthermore, it is essential if the basal shear zone daylights at the foot of the slope or encounters alluvial or glacial deposits at the bottom of the valley, the latter having a buttressing effect. In this study generic rock slide models with a shear zone outcropping at the slope toe are established and systematically analysed using limit equilibrium calculations. Two different kinematic types are modelled: (i) a translational or planar and (ii) a rotational movement behaviour. Questions concerning the impact of buoyancy and pore pressure forces that develop during first time impoundment are of key interest. Given that an adverse effect on the rock slide stability is expected due to reservoir impoundment the extent of destabilisation is highly dependent on the ratio of the rock mass volume affected by buoyancy forces to the total volume of the rock slide. If a large rock mass volume ratio is submerged, huge buoyancy forces evolve and destabilize the slope significantly. Additionally, the influence of impoundment velocity on the rock slide behaviour and the impact of material properties of the rock masses are analysed. Reservoir water rapidly infiltrates into high-permeable rock slide masses evolving high pore pressures at the basal shear zone which leads to destabilisation. Conversely, reservoir water infiltrates slowly into low-permeable rock masses and the destabilizing effect of the pore water pressure might be compensated by a buttressing reservoir load over the low-permeable rock masses. Preliminary steady state calculations show that the factor of safety decreases constantly with increasing reservoir level until a certain threshold reservoir level and minimum factor of safety is reached. After exceeding this threshold level a further increase in reservoir impoundment leads to an increase of the factor of safety. This threshold reservoir level is reliant on the rock slide geometry and rock mass volume affected by buoyancy. Upcoming research is expected to provide new fundamentals for a comprehensive understanding of deformation and failure processes of deep-seated rock slides in order to perform reliable forecasts.

  10. Hydrogeology of the upper Floridan Aquifer in the vicinity of the Marine Corps Logistics Base near Albany, Georgia

    USGS Publications Warehouse

    McSwain, Kristen Bukowski

    1999-01-01

    In 1995, the U.S. Navy requested that the U.S. Geological Survey conduct an investigation to describe the hydrogeology of the Upper Floridan aquifer in the vicinity of the Marine Corps Logistics Base, southeast and adjacent to Albany, Georgia. The study area encompasses about 90 square miles in the Dougherty Plain District of the Coastal Plain physiographic province, in Dougherty and Worth Counties-the Marine Corps Logistics Base encompasses about 3,600 acres in the central part of the study area. The Upper Floridan aquifer is the shallowest, most widely used source of drinking water for domestic use in the Albany area. The hydrogeologic framework of this aquifer was delineated by description of the geologic and hydrogeologic units that compose the aquifer; evaluation of the lithologic and hydrologic heterogeneity of the aquifer; comparison of the geologic and hydrogeologic setting beneath the base with those of the surrounding area; and determination of ground-water-flow directions, and vertical hydraulic conductivities and gradients in the aquifer. The Upper Floridan aquifer is composed of the Suwannee Limestone and Ocala Limestone and is divided into an upper and lower water-bearing zone. The aquifer is confined below by the Lisbon Formation and is semi-confined above by a low-permeability clay layer in the undifferentiated overburden. The thickness of the aquifer ranges from about 165 feet in the northeastern part of the study area, to about 325 feet in the southeastern part of the study area. Based on slug tests conducted by a U.S. Navy contractor, the upper water-bearing zone has low horizontal hydraulic conductivity (0.0224 to 2.07 feet per day) and a low vertical hydraulic conductivity (0.0000227 to 0.510 feet per day); the lower water-bearing zone has a horizontal hydraulic conductivity that ranges from 0.0134 to 2.95 feet per day. Water-level hydrographs of continuously monitored wells on the Marine Corps Logistics Base show excellent correlation between ground-water level and stage of the Flint River. Ground-water-flow direction in the southwestern part of the base generally is southeast to northwest; whereas, in the northeastern part of the base, flow directions generally are east to west, as well as from west to east, thus creating a ground-water low. Ground-water flow in the larger study area generally is east to west towards the Flint River, with a major ground-water-flow path existing from the Pelham Escarpment to the Flint River and a seasonal cone of depression the size of which is dependent upon the magnitude of irrigation pumping during the summer months. Calculated vertical hydraulic gradients (based upon data from 11 well-cluster sites on the Marine Corps Logistics Base) range from 0.0016 to 0.1770 foot per foot, and generally are highest in the central and eastern parts of the base. The vertical gradient is downward at all well-cluster sites.

  11. Geographic information system data sets of hydrogeologic conditions in Pequea and Mill Creek watersheds, Pennsylvania; Part I, basic data

    USGS Publications Warehouse

    Dugas, Diana L.; Char, Stephen J.; Baumbach, Gary E.

    1995-01-01

    This report describes basic data used to develop Geographic Information System data sets of bedrock geology, sinkholes and closed depressions, and spring and well locations attributed with hydro- geologic and water-quality data in the Pequea and Mill Creek watersheds, a 210-square-mile area in Lancaster and Chester Counties, Pa. The data sets, which do not contain hydrogeologic interpretations, were developed by the use of ARC/INFO software during 1990-93 by the U.S. Geological Survey, in cooperation with the Pennsylvania Department of Environmental Resources. The U.S. Environmental Protection Agency proposes to use these noninter- pretive and interpretive data sets, and those from other sources, to aid in the assessment of ground- water vulnerability to pesticides in the Pequea and Mill Creek watersheds.

  12. Character and distribution of exposed glaciodeltaic deposits off outer Cape Cod, Massachusetts, and their effects on hydrogeology and benthic habitats

    USGS Publications Warehouse

    Poppe, L.J.; Foster, D.S.; Danforth, W.W.

    2006-01-01

    Seabed outcrops of glaciodeltaic sediments were identified in four places east of Cape Cod, Massachusetts, during seismic-reflection, multibeam bathymetric and backscatter, bottom photographic, and sediment sampling surveys. These strata record coarser-grained ice-proximal glaciofluvial topset to finer-grained distal glaciolacustrine bottomset deposition within deltaic systems that prograded southwestward into glacial lakes from the South Channel lobe about 18 ka B.P. These beds are important because they (1) influence the outer Cape's hydrogeologic framework, and (2) constitute relatively stable, locally rough habitats within an area of seafloor dominated by mobile sand and gravelly sediment, and benefit the benthic fauna by providing shelter and a substrate amenable to burrow construction. ?? Springer-Verlag 2006.

  13. Contributions of hydrogeophysics to the hydrogeological conceptual model of the Albufeira-Ribeira de Quarteira coastal aquifer in Algarve, Portugal

    NASA Astrophysics Data System (ADS)

    Francés, Alain P.; Ramalho, Elsa C.; Fernandes, Judite; Groen, Michel; Hugman, Rui; Khalil, Mohamed A.; De Plaen, Joel; Monteiro Santos, Fernando A.

    2015-11-01

    Geoelectrical and electromagnetic (time and frequency domains) hydrogeophysical methods were applied and jointly interpreted together with auxiliary information such as regional piezometric maps, borehole lithological logs and offshore data. The objective was to retrieve the structure and geometry of the Albufeira-Ribeira de Quarteira coastal aquifer system (Algarve, Portugal) and to upgrade the current hydrogeological conceptual model. The results allowed for the detection of the freshwater-saltwater interface along the coastline and identification of the water-bearing layers and aquitards and their hydraulic relationships. An explanation for the location of the inter- and subtidal fresh groundwater discharge is also presented and a new modeling unit is proposed for groundwater flow modeling. Limitations of the used hydrogeophysical methods are indicated and recommendations are made for follow-up studies.

  14. Hydrogeologic controls on ground-water and contaminant discharge to the Columbia River near the Hanford Townsite

    SciTech Connect

    Luttrell, S.P.; Newcomer, D.R.; Teel, S.S.; Vermeul, V.R.

    1992-11-01

    The purpose of this study is to quantify ground-water and contaminant discharge to the Columbia River in the Hanford Townsite vicinity. The primary objectives of the work are to: describe the hydrogeologic setting and controls on ground-water movement and contaminant discharge to the Columbia River; understand the river/aquifer relationship and its effects on contaminant discharge to the Columbia River; quantify the ground-water and contaminant mass discharge to the Columbia River; and provide data that may be useful for a three-dimensional model of ground-water flow and contaminant transport in the Hanford Townsite study area. The majority of ground-water contamination occurs within the unconfined aquifer; therefore, ground-water and contaminant discharge from the unconfined aquifer is the emphasis of this study. The period of study is primarily from June 1990 through March 1992.

  15. Hydrogeologic, water-quality, streamflow, bottom-sediment analyses, and biological data near the Wayne County landfill, Wayne County, Tennessee

    USGS Publications Warehouse

    Quinones, F.; Bradfield, Arthur D.; Wescott, J.B.

    1992-01-01

    This report summarizes the data collected as part of a hydrogeologic investigation to determine the effects of the Wayne County landfill on local water quality. The investigation was conducted from 1988 through 1989 by the U.S. Geological Survey in cooperation with the Tennessee Department of Health and Environment, Division of Superfund. The landfill was closed in November 1984 after allegations that contaminants from the landfill were affecting the quality of water from domestic wells in the Banjo Branch-Hardin Hollow valley. Test well construction data; water-quality data for selected wells, seeps, and surface-water sites: streamflow data from Banjo Branch; analyses of bottom-sediment samples: and biological data for the study area are documented in this report.

  16. Lacustrine flow (divers, side scan sonar, hydrogeology, water penetrating radar) used to understand the location of a drowned person

    NASA Astrophysics Data System (ADS)

    Ruffell, Alastair

    2014-05-01

    An unusual application of hydrological understanding to a police search is described. The lacustrine search for a missing person provided reports of bottom-water currents in the lake and contradictory indications from cadaver dogs. A hydrological model of the area was developed using pre-existing information from side scan sonar, a desktop hydrogeological study and deployment of water penetrating radar (WPR). These provided a hydrological theory for the initial search involving subaqueous groundwater flow, focused on an area of bedrock surrounded by sediment, on the lake floor. The work shows the value a hydrological explanation has to a police search operation (equally to search and rescue). With hindsight, the desktop study should have preceded the search, allowing better understanding of water conditions. The ultimate reason for lacustrine flow in this location is still not proven, but the hydrological model explained the problems encountered in the initial search.

  17. Hydrogeologic framework and occurrence, movement, and chemical characterization of groundwater in Dixie Valley, west-central Nevada

    USGS Publications Warehouse

    Huntington, Jena M.; Garcia, C. Amanda; Rosen, Michael R.

    2014-01-01

    Dixie Valley, a primarily undeveloped basin in west-central Nevada, is being considered for groundwater exportation. Proposed pumping would occur from the basin-fill aquifer. In response to proposed exportation, the U.S. Geological Survey, in cooperation with the Bureau of Reclamation and Churchill County, conducted a study to improve the understanding of groundwater resources in Dixie Valley. The objective of this report is to characterize the hydrogeologic framework, the occurrence and movement of groundwater, the general water quality of the basin-fill aquifer, and the potential mixing between basin-fill and geothermal aquifers in Dixie Valley. Various types of geologic, hydrologic, and geochemical data were compiled from previous studies and collected in support of this study. Hydrogeologic units in Dixie Valley were defined to characterize rocks and sediments with similar lithologies and hydraulic properties influencing groundwater flow. Hydraulic properties of the basin-fill deposits were characterized by transmissivity estimated from aquifer tests and specific-capacity tests. Groundwater-level measurements and hydrogeologic-unit data were combined to create a potentiometric surface map and to characterize groundwater occurrence and movement. Subsurface inflow from adjacent valleys into Dixie Valley through the basin-fill aquifer was evaluated using hydraulic gradients and Darcy flux computations. The chemical signature and groundwater quality of the Dixie Valley basin-fill aquifer, and potential mixing between basin-fill and geothermal aquifers, were evaluated using chemical data collected from wells and springs during the current study and from previous investigations. Dixie Valley is the terminus of the Dixie Valley flow system, which includes Pleasant, Jersey, Fairview, Stingaree, Cowkick, and Eastgate Valleys. The freshwater aquifer in the study area is composed of unconsolidated basin-fill deposits of Quaternary age. The basin-fill hydrogeologic unit can be several orders of magnitude more transmissive than surrounding and underlying consolidated rocks and Dixie Valley playa deposits. Transmissivity estimates in the basin fill throughout Dixie Valley ranged from 30 to 45,500 feet squared per day; however, a single transmissivity value of 0.1 foot squared per day was estimated for playa deposits. Groundwater generally flows from the mountain range uplands toward the central valley lowlands and eventually discharges near the playa edge. Potentiometric contours east and west of the playa indicate that groundwater is moving eastward from the Stillwater Range and westward from the Clan Alpine Mountains toward the playa. Similarly, groundwater flows from the southern and northern basin boundaries toward the basin center. Subsurface groundwater flow likely enters Dixie Valley from Fairview and Stingaree Valleys in the south and from Jersey and Pleasant Valleys in the north, but groundwater connections through basin-fill deposits were present only across the Fairview and Jersey Valley divides. Annual subsurface inflow from Fairview and Jersey Valleys ranges from 700 to 1,300 acre-feet per year and from 1,800 to 2,300 acre-feet per year, respectively. Groundwater flow between Dixie, Stingaree, and Pleasant Valleys could occur through less transmissive consolidated rocks, but only flow through basin fill was estimated in this study. Groundwater in the playa is distinct from the freshwater, basin-fill aquifer. Groundwater mixing between basin-fill and playa groundwater systems is physically limited by transmissivity contrasts of about four orders of magnitude. Total dissolved solids in playa deposit groundwater are nearly 440 times greater than total dissolved solids in the basin-fill groundwater. These distinctive physical and chemical flow restrictions indicate that groundwater interaction between the basin fill and playa sediments was minimal during this study period (water years 2009–11). Groundwater in Dixie Valley generally can be characterized as a sodium bicarbonate type, with greater proportions of chloride n

  18. Description and hydrogeologic implications of cored sedimentary material from the 1975 drilling program at the radioactive waste management complex, Idaho

    USGS Publications Warehouse

    Rightmire, C.T.

    1984-01-01

    Samples of sedimentary material from interbeds between basalt flows and from fractures in the flows, taken from two drill cores at the Radioactive Waste Management Complex at the Idaho National Engineering Laboratory were analyzed for (1) particle-size dribution, (2) bulk mineralogy, (3) clay mineralogy, (4) cation-exchange capacity, and (5) carbonate content. Thin sections of selected sediment material were made for petrographic examination. Preliminary interpretations indicate that (1) it may be possible to distinguish the various sediment interbeds on the basis of their mineralogy, (2) the presence of carbonate horizons in sedimentary interbeds may be utilized to approximate the time of exposure and the climate while the surface was exposed (which affected the hydrogeologic character of the sediment), and the type and orientation of fracture-filling material may be utilized to determine the mechanism by which fractures were filled. (USGS)

  19. Compilation of Water-Resources Data and Hydrogeologic Setting for Brunswick County, North Carolina, 1933-2000

    USGS Publications Warehouse

    Fine, Jason M.; Cunningham, William L.

    2001-01-01

    Water-resources data were compiled for Brunswick County, North Carolina, to describe the hydrologic conditions of the County. Hydrologic data collected by the U.S. Geological Survey as well as data collected by other governmental agencies and reviewed by the U.S. Geological Survey are presented. Data from four weather stations and two surface-water stations are summarized. Data also are presented for land use and land cover, soils, geology, hydrogeology, 12 continuously monitored ground-water wells, 73 periodically measured ground-water wells, and water-quality measurements from 39 ground-water wells. Mean monthly precipitation at the Longwood, Shallotte, Southport, and Wilmington Airport weather stations ranged from 2.19 to 7.94 inches for the periods of record, and mean monthly temperatures at the Longwood, Southport, and Wilmington Airport weather stations ranged from 43.4 to 80.1 degrees Fahrenheit for the periods of record. An evaluation of land-use and land-cover data for Brunswick County indicated that most of the County is either forested land (about 57 percent) or wetlands (about 29 percent). Cross sections are presented to illustrate the general hydrogeology beneath Brunswick County. Water-level data for Brunswick County indicate that water levels ranged from about 110 feet above mean sea level to about 22 feet below mean sea level. Chloride concentrations measured in aquifers in Brunswick County ranged from near 0 to 15,000 milligrams per liter. Chloride levels in the Black Creek and Cape Fear aquifers were measured at well above the potable limit for ground water of 250 milligrams per liter set by the U.S. Environmental Protection Agency for safe drinking water.

  20. Geologic framework and hydrogeologic features of the Glen Rose Limestone, Camp Bullis Training Site, Bexar County, Texas

    USGS Publications Warehouse

    Clark, Allan K.

    2003-01-01

    The Glen Rose Limestone crops out over most of the Camp Bullis Training Site in northern Bexar County, Texas, where it consists of upper and lower members and composes the upper zone and the upper part of the middle zone of the Trinity aquifer. Uncharacteristically permeable in northern Bexar County, the Glen Rose Limestone can provide avenues for recharge to and potential contamination of the downgradient Edwards aquifer, which occupies the southeastern corner of Camp Bullis. The upper member of the Glen Rose Limestone characteristically is thin-bedded and composed mostly of soft limestone and marl, and the lower Glen Rose typically is composed mostly of relatively massive, fossiliferous limestone. The upper member, about 410 to 450 feet thick at Camp Bullis, was divided in this study into five hydrogeologic subdivisions, A through E (youngest to oldest). The approximately 120-foot-thick Interval A has an abundance of caves, which is indicative of its generally well developed fracture, channel, and cavern porosity that in places provides appreciable permeability. The 120- to 150-foot-thick Interval B is similar to Interval A but with less cave development and considerably less permeability. The 10- to 20-foot-thick Interval C, a layer of partly to mostly dissolved soluble carbonate minerals, is characterized by breccia porosity, boxwork permeability, and collapse structures that typically divert ground water laterally to discharge at land surface. The 135- to 180-foot-thick Interval D generally has low porosity and little permeability with some local exceptions, most notably the caprinid biostrome just below the top of the interval, which appears to be permeable by virtue of excellent moldic, vug, fracture, and cavern porosity. The 10- to 20-foot-thick Interval E, a layer of partly to mostly dissolved evaporites similar to Interval C, has similar hydrogeologic properties and a tendency to divert ground water laterally.

  1. Investigating the Hydrogeologic Controls on Memory and Feedbacks to Climate Change in Mountain Groundwater Systems: An Integrated Modeling Approach

    NASA Astrophysics Data System (ADS)

    Markovich, K. H.; Fogg, G. E.; Maxwell, R. M.

    2014-12-01

    Rising global temperatures are profoundly impacting alpine environments by shifting the precipitation type and the timing of peak snowmelt runoff. Uncertainty in the magnitude of these shifts translates to uncertainty in how climate change affects timing of snowmelt runoff, and hence availability of surface water during the remainder of the year. Integrated hydrologic models are useful tools for capturing these feedbacks by closing the loop between atmosphere, land surface, and subsurface dynamics. Recent integrated models have been used to predict streamflow response to climate change in mountain basins, however these models assume that shallow, local flow paths comprise the majority of recharge and baseflow to streams. Several studies have challenged this assumption with discordant groundwater ages and hysteresis loops, suggesting that deep, regional flow paths may play a more substantial role even at the local stream scale. This would have considerable implications for predicted responses to climate change in alpine basins, as deep, regional groundwater would initially buffer perturbations, but exhibit greater memory over the long-term. The goal of this study is to understand how various hydrogeological settings will control the relative feedbacks to climate change. This research uses three simplified, conceptual hillslope models: a "fast" draining, low storage, granodiorite similar to that of of the Sierra Nevada or Himalayan mountain range, a "slow" draining, high storage basalt of the Cascade or Andes Range, and a vertically homogeneous "base" case. The relative response of these hillslopes to three future climate scenarios: warm, warm and dry, and warm and wet are tested using ParFlow, an integrated surface water-groundwater model, coupled with CLM, a land surface model. These models will help quantify the relative feedbacks of deep groundwater in various hydrogeologic settings and will ultimately be scaled up to assess the 3-D, transient response of deep groundwater to climate change in a regional alpine system.

  2. The GIS layers of the "International Hydrogeological Map of Europe 1:1,500,000" in a vector format

    NASA Astrophysics Data System (ADS)

    Duscher, Klaus; Günther, Andreas; Richts, Andrea; Clos, Patrick; Philipp, Uta; Struckmeier, Wilhelm

    2015-08-01

    The map series of the International Hydrogeological Map of Europe at a scale of 1:1,500,000 (IHME1500) has been completed by the publication of the last two map sheets in August 2013. Altogether, the 25 sheets of the IHME1500 provide the first coherent overview of groundwater resources in Europe. The map displays productivity and lithology of potential aquifer systems. Some of the additional map contents relating to groundwater are presented only regionally. The most relevant features of IHME1500 are compiled in two seamless geographic information system (GIS) layers in shapefile format: (1) showing groundwater resources characterised by a basic aquifer typology, including a lithological description and areas of seawater intrusion, and (2) reproducing major tectonic fractures. The superficial lithology information was harmonised by implementing a lithological taxonomy and a multi-step aggregation. An enhancement of the GIS layers is envisaged through the release of updates, which will be distinguished by consecutive version numbers. The continent-wide harmonised presentation of contents constitutes the main feature of the IHME1500 GIS layers. This qualifies the spatial dataset as a basic tool for hydrogeological assessments aiming primarily at transboundary issues. Map scale and the manufacture date of the analogue base impose restrictions on the application of the IHME1500 vector data. A set of examples describes the initial use of the GIS layers in research projects and illustrates potential fields of application. The IHME1500 lithology layer establishes a spatial dataset suitable for the continent-wide evaluation of geological surface processes like the susceptibility to landslides.

  3. Hydrogeological restrictions to saline ground-water discharge in the Red River of the North drainage basin, North Dakota

    SciTech Connect

    Strobel, M.L. Univ. of North Dakota, Grand Forks, ND )

    1992-01-01

    Discharge of saline water from bedrock aquifers along the eastern margin of the Williston basin is restricted by surficial glacial till and lacustrine deposits in the Red River of the North drainage basin. Water from these aquifers reaches the surface by (1) diffusion; (2) slow, upward seepage along zones of relatively larger hydraulic conductivity in the till and lacustrine deposits; or (3) flow from artesian wells. Ground-water quality varies near the surface because of mixing of water being discharged from bedrock aquifers with shallower ground water in the surficial deposits. Ground-water quality, hydraulic-gradient, and hydraulic-conductivity data obtained from pumped-well and slug tests indicate that flow in the surficial deposits is eastward, but at slow rates because of small hydraulic conductivities. Base-flow and specific-conductance measurements of water in tributaries to the Red River of the North indicate that focused points of ground-water discharge result in substantial increases in salinity in surface water in the northern part of the basin in North Dakota. Core analyses and drillers' logs were used to generalize hydrogeologic characteristics of the deposits in the basin, and a two-dimensional ground-water-flow model was used to simulate the basin's geohydrologic processes. Model results indicate that the ground-water flow paths in the bedrock aquifers and surficial deposits converge, and that water from the bedrock aquifers contributes to the overall increase in ground-water discharge toward the east. Model results are supported by water-quality data collected along an east-west hydrogeologic section.

  4. Characterization of the hydrogeology and stress state in the vicinity of the homestake mine, Lead, SD

    NASA Astrophysics Data System (ADS)

    Ebenhack, Johnathan Foss

    Underground workings in fractured rock are common worldwide. They have applications in numerous areas and fields of study. These include mining operations, civil engineering projects like tunnels and underground facilities, and research projects that require underground laboratories such as the physics research being conducted by Sanford Laboratory at the former Homestake mine and Fermi Laboratory near Chicago (Bahcall et al. 2001, Elsworth 2009, Sadoulet et al. 2006, bge science DUSEL, fnal.gov). These excavations can reach several kilometers in depth including the 3.9 km deep TauTona mine in South Africa, the 3 km deep LaRonde mine in Quebec and the 2.4 km deep Homestake mine in South Dakota. Large quantities of rock are removed when constructing deep excavations, for example Rahn and Roggenthen (2002) estimated the total volume of rock removed from the Homestake mine to be 2.1x107 m3. Removing large volumes of rock alters the local stress state and ground water flow, potentially increasing risks to workers and the environment (Kaiser et al. 2008, Blodgett et al. 2002, Lucier et al. 2009, Goldbach 2010, Kang et al. 2010). The objective of this research is to develop a better understanding of how deep rock excavations can alter groundwater flow, stress state, and deformation in the rock that envelopes them. The approach is to evaluate how the hydraulic head, flow paths and stress state have been affected by excavation at the Homestake mine in Lead, South Dakota, one of the deepest mines in North America. The Homestake mine was selected as a focus of this research because it has recently been evaluated as the site of a deep underground research laboratory where an understanding of the groundwater flow and stress state was needed to plan underground experiments. The investigation includes poroelastic modeling of the Homestake mine using available geologic and geophysical data and mine records. Results from the analyses indicate that mining and dewatering have changed the hydrology and stress state in the vicinity of the Homestake mine. Dewatering reduces the hydraulic head and changes the flow systems in the vicinity of the mine. Four major hydrogeologic zones are recognized: 1.) a Shallow Flow System in the upper few hundred meters that dominates recharge and discharge to streams, 2.) a Recharge Capture Zone where water that has entered the region as recharge since mining began is captured by the mine, 3.) a Storage Capture Zone where water from storage in the host rock around the mine is captured, and 4.) a Mine Workings Zone where rock has been removed. Water enters the system at the top of the Shallow Flow System and either discharges to the streams or flows downward and becomes recharge to the lower capture zones. The Recharge Capture Zone grows with time as regions of storage are depleted and new recharge enters, and eventually it is assumed that the entire capture zone for the mine will become the Recharge Capture Zone. Fluxes from the Shallow Flow System to the Recharge Capture Zone typically range from 1x10-9 to 4x10-9 m/s. The largest recharge fluxes from the Shallow Flow System to the Recharge Capture Zone occur above the shallowest portions of the mine. Recharge flux also occurs above areas adjacent to the mine, and when projected to the surface the Recharge Capture Zone creates a roughly elliptical shape that is 6 km x 3.6 km. The Storage Capture Zone extends out beyond and below the Recharge Capture Zone and when projected to the surface creates a roughly elliptical region that is approximately 8.3 km x 6.6 km and extends down to depths of almost 5 km. Hydraulic heads and flow paths have been affected beyond the Storage Capture Zone but this water had not reached the mine by 135 years and therefore these regions are not included in the capture zones. The model was calibrated using in-situ stress data at various points in the mine to improve its ability to estimate the stress state and mechanical deformation around the Homestake mine. This was done by varying the rock density, Poisson's ratio, the effective Y

  5. Consequences of marginal drainage from a raised bog and understanding the hydrogeological dynamics as a basis for restoration

    NASA Astrophysics Data System (ADS)

    Regan, Shane; Johnston, Paul

    2010-05-01

    Raised bogs in Ireland have long been exploited for local fuel utilisation. The drainage associated with such activities alters the hydrological regime of the bog as consolidation of the peat substrate results in significant water loss and subsidence of the bog. Undisturbed raised bog environments are typically characterised by distinct ecological systems, or ecotopes, which are controlled by the relationship between surface slopes, flow path lengths and drainage conditions. Shrinkage of the main peat profile, or catotelm, invariably alters these conditions, changes of which significantly damage ecotopes of conservational value. Clara Bog, Ireland, is one of western Europe's largest remaining raised bogs and on which much hydroecological research has been conducted since the early 1990's. Though a relatively intact raised bog, it has been extensively damaged in the past with the construction of a road through the centre of the bog known to have resulted in subsidence of 9-10m. However, the western tract of Clara Bog, Clara Bog West, has also subsided significantly since the early 1990's due to on-going peat cutting activities on the bogs margins. Current research now indicates that the bog is not an isolated hydrological entity, as generally perceived of bogs, but rather that Clara Bog West is intrinsically linked to the regional groundwater table, which appears to provide a significant ‘support' function to the bog. Hydrogeological monitoring and analysis has shown that water losses are not simply a result of lateral seepage of water through the peat profile at the bogs margins. Measurements of flow rates and electrical conductivity in drains bordering the bog indicate that little water is discharging laterally through the peat profile. However, piezometric head levels in mineral subsoil underlying the bog and close to the margins of the bog have decreased by 0.3 to 0.5m and 0.4 to 1.0m respectively since the early 1990s and it is believed that this is a result of vertical water losses in the peat profile not confined to the bog margins. Distinct zones of groundwater seepage in the marginal drains have been mapped based on hydrochemical and stable isotopic composition of the water and occur where drains have cut into permeable subsoil beneath the peat substrate and where the potentiometric surface of the regional groundwater table is below, or coincident with, the elevation at the base of the drain. Groundwater as a ‘supporting' ecological condition is usually confined to the perimeter of a raised bog, where peat and underlying clay thin towards the margin, allowing regional groundwater and peat water to converge and mix, thereby giving rise to characteristic nutrient rich ‘lagg' zone vegetation. However, in Clara Bog West it appears there is also a connection between the regional groundwater table and the high bog. Such a connection appears to be unique to Clara Bog West as a result of the prevailing geological conditions. A succession of Carboniferous Limestone to relatively permeable glacial till deposits to low permeability lacustrine clay sediment is the predominant underlying geology of the bog. However, there are areas where the glacial till protrudes through the lacustrine clay, which ordinarily isolates the high bog from underlying groundwater, thereby engendering a dependency on regional groundwater conditions. The hydrogeological data now suggest that drainage at the bog margin has created a hydraulic connection between these ‘subsoil subcrops' and the marginal drains, developed within the same subsoil, thereby lowering the regional groundwater table, steepening the hydraulic gradient and resulting in significant water loss from the main bog body. As such, understanding this hydrogeological connection is central to restoration activities that will aim to arrest subsidence and restore water levels that are indicative for ecotope development, on the high bog. Acknowledgements Clara Restoration Group: Jan Streekferk (Staatsbosbeheer), Jim Ryan (National Parks and Wildlife Service), Ray Flynn (Queens Univ

  6. Death Valley regional ground-water flow system, Nevada and California -- hydrogeologic framework and transient ground-water flow model

    USGS Publications Warehouse

    : Belcher, Wayne R., (Edited By)

    2004-01-01

    A numerical three-dimensional (3D) transient ground-water flow model of the Death Valley region was developed by the U.S. Geological Survey for the U.S. Department of Energy programs at the Nevada Test Site and at Yucca Mountain, Nevada. Decades of study of aspects of the ground-water flow system and previous less extensive ground-water flow models were incorporated and reevaluated together with new data to provide greater detail for the complex, digital model. A 3D digital hydrogeologic framework model (HFM) was developed from digital elevation models, geologic maps, borehole information, geologic and hydrogeologic cross sections, and other 3D models to represent the geometry of the hydrogeologic units (HGUs). Structural features, such as faults and fractures, that affect ground-water flow also were added. The HFM represents Precambrian and Paleozoic crystalline and sedimentary rocks, Mesozoic sedimentary rocks, Mesozoic to Cenozoic intrusive rocks, Cenozoic volcanic tuffs and lavas, and late Cenozoic sedimentary deposits of the Death Valley Regional Ground-Water Flow System (DVRFS) region in 27 HGUs. Information from a series of investigations was compiled to conceptualize and quantify hydrologic components of the ground-water flow system within the DVRFS model domain and to provide hydraulic-property and head-observation data used in the calibration of the transient-flow model. These studies reevaluated natural ground-water discharge occurring through evapotranspiration and spring flow; the history of ground-water pumping from 1913 through 1998; ground-water recharge simulated as net infiltration; model boundary inflows and outflows based on regional hydraulic gradients and water budgets of surrounding areas; hydraulic conductivity and its relation to depth; and water levels appropriate for regional simulation of prepumped and pumped conditions within the DVRFS model domain. Simulation results appropriate for the regional extent and scale of the model were provided by acquiring additional data, by reevaluating existing data using current technology and concepts, and by refining earlier interpretations to reflect the current understanding of the regional ground-water flow system. Ground-water flow in the Death Valley region is composed of several interconnected, complex ground-water flow systems. Ground-water flow occurs in three subregions in relatively shallow and localized flow paths that are superimposed on deeper, regional flow paths. Regional ground-water flow is predominantly through a thick Paleozoic carbonate rock sequence affected by complex geologic structures from regional faulting and fracturing that can enhance or impede flow. Spring flow and evapotranspiration (ET) are the dominant natural ground-water discharge processes. Ground water also is withdrawn for agricultural, commercial, and domestic uses. Ground-water flow in the DVRFS was simulated using MODFLOW-2000, a 3D finite-difference modular ground-water flow modeling code that incorporates a nonlinear least-squares regression technique to estimate aquifer parameters. The DVRFS model has 16 layers of defined thickness, a finite-difference grid consisting of 194 rows and 160 columns, and uniform cells 1,500 m on each side. Prepumping conditions (before 1913) were used as the initial conditions for the transient-state calibration. The model uses annual stress periods with discrete recharge and discharge components. Recharge occurs mostly from infiltration of precipitation and runoff on high mountain ranges and from a small amount of underflow from adjacent basins. Discharge occurs primarily through ET and spring discharge (both simulated as drains) and water withdrawal by pumping and, to a lesser amount, by underflow to adjacent basins, also simulated by drains. All parameter values estimated by the regression are reasonable and within the range of expected values. The simulated hydraulic heads of the final calibrated transient model gener

  7. Death Valley regional groundwater flow system, Nevada and California-Hydrogeologic framework and transient groundwater flow model

    USGS Publications Warehouse

    : Belcher, Wayne R., (Edited By); Sweetkind, Donald S.

    2010-01-01

    A numerical three-dimensional (3D) transient groundwater flow model of the Death Valley region was developed by the U.S. Geological Survey for the U.S. Department of Energy programs at the Nevada Test Site and at Yucca Mountain, Nevada. Decades of study of aspects of the groundwater flow system and previous less extensive groundwater flow models were incorporated and reevaluated together with new data to provide greater detail for the complex, digital model. A 3D digital hydrogeologic framework model (HFM) was developed from digital elevation models, geologic maps, borehole information, geologic and hydrogeologic cross sections, and other 3D models to represent the geometry of the hydrogeologic units (HGUs). Structural features, such as faults and fractures, that affect groundwater flow also were added. The HFM represents Precambrian and Paleozoic crystalline and sedimentary rocks, Mesozoic sedimentary rocks, Mesozoic to Cenozoic intrusive rocks, Cenozoic volcanic tuffs and lavas, and late Cenozoic sedimentary deposits of the Death Valley regional groundwater flow system (DVRFS) region in 27 HGUs. Information from a series of investigations was compiled to conceptualize and quantify hydrologic components of the groundwater flow system within the DVRFS model domain and to provide hydraulic-property and head-observation data used in the calibration of the transient-flow model. These studies reevaluated natural groundwater discharge occurring through evapotranspiration (ET) and spring flow; the history of groundwater pumping from 1913 through 1998; groundwater recharge simulated as net infiltration; model boundary inflows and outflows based on regional hydraulic gradients and water budgets of surrounding areas; hydraulic conductivity and its relation to depth; and water levels appropriate for regional simulation of prepumped and pumped conditions within the DVRFS model domain. Simulation results appropriate for the regional extent and scale of the model were provided by acquiring additional data, by reevaluating existing data using current technology and concepts, and by refining earlier interpretations to reflect the current understanding of the regional groundwater flow system. Groundwater flow in the Death Valley region is composed of several interconnected, complex groundwater flow systems. Groundwater flow occurs in three subregions in relatively shallow and localized flow paths that are superimposed on deeper, regional flow paths. Regional groundwater flow is predominantly through a thick Paleozoic carbonate rock sequence affected by complex geologic structures from regional faulting and fracturing that can enhance or impede flow. Spring flow and ET are the dominant natural groundwater discharge processes. Groundwater also is withdrawn for agricultural, commercial, and domestic uses. Groundwater flow in the DVRFS was simulated using MODFLOW-2000, the U.S. Geological Survey 3D finitedifference modular groundwater flow modeling code that incorporates a nonlinear least-squares regression technique to estimate aquifer parameters. The DVRFS model has 16 layers of defined thickness, a finite-difference grid consisting of 194 rows and 160 columns, and uniform cells 1,500 meters (m) on each side. Prepumping conditions (before 1913) were used as the initial conditions for the transient-state calibration. The model uses annual stress periods with discrete recharge and discharge components. Recharge occurs mostly from infiltration of precipitation and runoff on high mountain ranges and from a small amount of underflow from adjacent basins. Discharge occurs primarily through ET and spring discharge (both simulated as drains) and water withdrawal by pumping and, to a lesser amount, by underflow to adjacent basins simulated by constant-head boundaries. All parameter values estimated by the regression are reasonable and within the range of expected values. The simulated hydraulic heads of the final calibrated transient mode

  8. Remote sensing and hydrogeological methodologies for irrigation canal leakage detection: the Osasco and Fossano test sites (NorthWestern Italy)

    NASA Astrophysics Data System (ADS)

    Perotti, Luigi; Clemente, Paolo; De Luca, Domenico Antonio; Dino, Giovanna; Lasagna, Manuela

    2013-04-01

    Seventy percent of global fresh water is usually used for irrigation. This rate is three times the amount of water used by industry and ten times the amount used in domestic and urban environment (Hotchkiss et al., 2001). However, the average efficiency of the water transport for agricultural purposes in different contexts (at world scale) is variable between 30% and 80%. Studies conducted in Italy confirms that rates are similar from the case studies abroad. In this research, satellite image analysis and hydrological-hydrogeological methods were used in two pilot sites (Osasco channel and Fossano channel, in the Noth-Western Italy) to identify the areas most prone to this problem and to quantify the losses. The aim of the study is to define a multidisciplinary approach in order to identify the critical situations of irrigation channels for a sustainable water resource use and management. The use of remote sensing techniques can identify, on a regional scale and at relative low cost, the channels section potentially critical upon which focus the attention and perform in-situ investigation. The presence of leakage from the irrigation canals, indeed, tends to induce variations of moisture on the surface ground. These variations affect the vegetation (e.g. vegetation state), and certain physical characteristics of the soil (e.g. the capacity and thermal conductivity). The analysis of these anomalies, conducted with digital image processing techniques (with infrared spectrum bands particularly sensitive to the above indicators) help to identify those areas with anomalies related to increased losses (Huang and Fipps, 2002). The use of satellite imagery in the proposed approach is an innovative application of Earth Observation for land and water monitoring (Huang et al., 2005). After the identification of anomalies, hydrological-hydrogeological methods were applied to evaluate the losses. At fist an hydrogeological characterisation of the study area and the bottom of the irrigation channel were conducted. Then the canals seepage rates were estimated using inflow-outflow tests and tests with double-tracer, an adaptation from QUEST method (Rieckermann and Gujer, 2002). This approach allowed an experimental calibration and validation of the satellite images analysis. The applied multidisciplinary approach seem to be a promising way for a good general screening for a rapid detection of irrigation channels water losses. References Hotchkiss, R.H., Wingert, C.B., Kelly, W.E., 2001. Determining irrigation canal seepage with electrical resistivity. ASCE J. Irrig. Drain 127, 20-26. Huang Y and Fipps G. (2002). Thermal Imaging of Canals for Remote Detection of Leaks: Evaluation in the United Irrigation District. Technical Report. Biological and Agricultural Engineering Department, Texas A&M University. Huang Y, Fipps G, Maas S, Fletcher R. (2005). Airborne multispectral remote sensing imaging for detecting irrigation canal leaks in the lower rio grande valley - 20th Biennial Workshop on Aerial Photography, Videography, and High Resolution Digital Imagery for Resource Assessment October 4-6, Weslaco, Texas. Rieckermann J., Gujer W. (2002) - Quantifying Exfiltration from Leaky Sewers with Artificial Tracers - Proceedings of the International Conference on "Sewer Operation and Maintenance. 2002", Bradford, UK.

  9. Calendar year 1994 groundwater quality report for the Upper East Fork Poplar Creek Hydrogeologic Regime, Y-12 Plant, Oak Ridge, Tennessee

    SciTech Connect

    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 waste-management facilities and a petroleum fuel underground storage tank (UST) site at the US Department of Energy (DOE) Y-12 Plant located on the DOE Oak Ridge Reservation (ORR) southeast of Oak Ridge, Tennessee. These sites lie within the boundaries of the Upper East Fork Poplar Creek Hydrogeologic Regime (East Fork Regime), which is one of three hydrogeologic regimes defined for the purposes of groundwater quality monitoring at the Y-12 Plant. The Environmental Management Department of the Y-12 Plant Health, Safety, Environment, and Accountability (HSEA) Organization manages the groundwater monitoring activities in each regime 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 ensure protection of local groundwater resources in accordance with federal, state, and local regulations, DOE Orders, and Lockheed Martin Energy Systems, Inc. (Energy Systems) corporate policy.

  10. Hydrogeology and simulation of groundwater flow in the Central Oklahoma (Garber-Wellington) Aquifer, Oklahoma, 1987 to 2009, and simulation of available water in storage, 2010-2059

    USGS Publications Warehouse

    Mashburn, Shana L.; Ryter, Derek; Neel, Christopher R.; Smith, S. Jerrod; Magers, Jessica S.

    2014-01-01

    The Central Oklahoma (Garber-Wellington) aquifer underlies about 3,000 square miles of central Oklahoma. The study area for this investigation was the extent of the Central Oklahoma aquifer. Water from the Central Oklahoma aquifer is used for public, industrial, commercial, agricultural, and domestic supply. With the exception of Oklahoma City, all of the major communities in central Oklahoma rely either solely or partly on groundwater from this aquifer. The Oklahoma City metropolitan area, incorporating parts of Canadian, Cleveland, Grady, Lincoln, Logan, McClain, and Oklahoma Counties, has a population of approximately 1.2 million people. As areas are developed for groundwater supply, increased groundwater withdrawals may result in decreases in long-term aquifer storage. The U.S. Geological Survey, in cooperation with the Oklahoma Water Resources Board, investigated the hydrogeology and simulated groundwater flow in the aquifer using a numerical groundwater-flow model. The purpose of this report is to describe an investigation of the Central Oklahoma aquifer that included analyses of the hydrogeology, hydrogeologic framework of the aquifer, and construction of a numerical groundwater-flow model. The groundwater-flow model was used to simulate groundwater levels and for water-budget analysis. A calibrated transient model was used to evaluate changes in groundwater storage associated with increased future water demands.

  11. The alerting system for hydrogeological hazard in Lombardy Region, northern Italy: rainfall thresholds triggering debris-flows and "equivalent rainfall" method

    NASA Astrophysics Data System (ADS)

    Cucchi, A.; Valsecchi, I. Q.; Alberti, M.; Fassi, P.; Molari, M.; Mannucci, G.

    2015-01-01

    The Functional Centre (CFMR) of the Civil Protection of the Lombardy Region, North Italy, has the main task of monitoring and alerting, particularly with respect to natural hazards. The procedure of early warning for hydrogeological hazard is based on a comparison of two quantities: thresholds and rainfall, both referred to a defined area and an exact time interval. The CFMR studied 52 landslide events (1987-2003) in Medium-Low Valtellina and derived a model of the critical detachment rainfall, in function of the local slope and the Curve Number CN (an empirical parameter related with the land cover and the hydrological conditions of the soil): it's physically consistent and allows a geographically targeted alerting. Moreover, rainfall thresholds were associated with a typical probability of exceedance. The processing of rainfall data is carried out through the "equivalent rainfall" method, that allows to take into account the antecedent moisture condition of the soil: in fact the hazard is substantially greater when the soil is near to saturation. The method was developed from the CN method and considers the local CN and the observed rainfall of the previous 5 days. The obtained value for the local equivalent rainfall, that combines rainfall (observed and forecasted) and local soil characteristics, is a better parameter for the evaluation of the hydrogeological hazard. The comparison between equivalent rainfall and thresholds allows to estimate the local hydrogeological hazard, displayed through hazard maps, and consequently to provide a reliable alerting activity (even localized to limited portions of the region).

  12. A three-dimensional hydrogeological-geophysical model of a multi-layered aquifer in the coastal alluvial plain of Sarno River (southern Italy)

    NASA Astrophysics Data System (ADS)

    Di Maio, R.; Fabbrocino, S.; Forte, G.; Piegari, E.

    2014-05-01

    The coastal alluvial plain of Sarno River (Campania Region, southern Italy) is a very rich environment that has experienced a long history of changes due to both natural phenomena such as eustatic sea-level variations and deposition of volcanoclastic sediments, and human civilizations who populated this area since historical times. As a result, it is characterized by complex stratigraphic sequences and groundwater flow systems. The architecture of the multi-layered aquifer system in a sample area, located in a densely urbanized sector at the mouth of Sarno River, was reconstructed. Starting from the analysis of stratigraphic log data and laboratory geotechnical measurements, the lithostratigraphical-unit sequence was retrieved and a realistic three-dimensional (3D) model of the hydrogeological heterogeneity was obtained. The results of a detailed 2D electrical resistivity tomography survey were used to support the analysis of the spatial heterogeneity of the aquifer system in a sector characterized by lack of log data. The integration of hydrogeological and geophysical data allowed for the reconstruction of a 3D hydrogeophysical model of the multi-layered system, which electrically characterizes and geometrically identifies two aquifers. Finally, piezometric-level measurements validated the hydrogeological-geophysical model and showed the effectiveness of the methodology.

  13. Hydrogeologic and water-quality reconnaissance of the artesian aquifer under the Shoalwater Bay Indian Reservation and Tokeland Peninsula, Pacific County, Washington, 1998-99

    USGS Publications Warehouse

    Lane, R.C.; Ebbert, J.C.

    2002-01-01

    The U.S. Geological Survey (USGS) collected and compiled hydrogeologic and water quality data from September 1998 through September 1999 to describe the hydrogeologic setting and to assess the quality of the water in the artesian aquifer under the Shoalwater Bay Indian Reservation and the adjacent Tokeland Peninsula area of Pacific County, Washington. Hydrogeologic data include descriptions of 38 wells, lithologic data for 27 wells, and water-level data for 17 wells and 1 tidal station. Water-quality data include field measurements for temperature, specific conductance, pH, alkalinity, bicarbonate, carbonate, dissolved oxygen, and laboratory analyses for major inorganic ions, metals, nutrients, methylene blue-active substances, and pesticides. None of the 93 field measurements or chemicals analyzed for exceeded the U.S. Environmental Protection Agency (USEPA) primary standards for drinking water and only 2 constituents (iron and manganese) exceeded the USEPA secondary standards. Sixty-six of the constituents (including all 53 pesticides) were at or below the reporting or detection levels established by the USGS National Water Quality Laboratory.

  14. Hydrogeology and water quality of the Galena-Platteville aquifer at the Parson's Casket Hardware Superfund site, Belvidere, Illinois, 1991

    USGS Publications Warehouse

    Mills, P.C.

    1993-01-01

    The U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, investigated the hydrogeology of the Galena-Platteville aquifer and its relation to contaminant migration at the Parson's Casket Hardware Superfund site in Belvidere, Ill. This report presents the results of the second phase of the investigation, which lasted from March through October 1991. The uppermost bedrock units beneath the study site are the Galena and Platteville Groups1; these bedrock units immediately underlie a glacial drift aquifer. The Galena and Platteville Groups, which consist predominantly of dolomite, compose the Galena-Platteville aquifer, and extend from about 40 to 320 feet below land surface. The unconfined Galena-Platteville aquifer is partitioned into five hydrogeologic units. The uppermost unit, the weathered surface of the bedrock, has a horizontal hydraulic conductivity that ranges from about 1 to 200 feet per day. The four underlying units have hydraulic conductivities that range from about 0.01 to 1 foot per day. Vertical hydraulic gradients in the aquifer are typically downward. Horizontal groundwater flow generally is southward to southeastward from the site toward the Kishwaukee River. Three notable bedding-plane solution fissures and three fractures that crosscut the bedding planes are identified within the dolomite bedrock. The inclined fractures are assumed to function as conduits that connect high conductivity horizontal fissures, thus allowing more rapid vertical movement of ground water and contaminants than would be expected in the generally low conductivity dolomite matrix. A multiple-well, constant-discharge aquifer test confirms the heterogeneity and anisotropy of the dolomite aquifer. The hydraulic characteristics of the uppermost part of the bedrock aquifer are somewhat different than the characteristics of the deeper part(s) of the aquifer. This is because the principal conduits for water movement are in the deeper part(s) of the aquifer. Ground-water flow in the Galena-Platteville aquifer beneath the study site is affected by pumping of Belvidere Municipal Wells No. 4 and No. 6. Water levels in wells screened near the vertical midpoint of the aquifer are affected by the municipal-well pumping substantially more than are water levels in wells screened near the top of the aquifer.

  15. Geologic framework, structure, and hydrogeologic characteristics of the Knippa Gap area in eastern Uvalde and western Medina Counties, Texas

    USGS Publications Warehouse

    Clark, Allan K.; Pedraza, Diana E.; Morris, Robert R.

    2013-01-01

    The Edwards aquifer is the primary source of potable water for the San Antonio area in south-central Texas. The Knippa Gap was postulated to channel or restrict flow in the Edwards aquifer in eastern Uvalde County, and its existence was based on a series of numerical simulations of groundwater flow in the aquifer. To better understand the function of the area known as the Knippa Gap as it pertains to its geology and structure, the geologic framework, structure, and hydrogeologic characteristics of the area were evaluated by the U.S. Geological Survey in cooperation with the U.S. Army Corps of Engineers-Fort Worth District. The principal structural feature in the San Antonio area is the Balcones Fault Zone, which is the result of Miocene age faulting. In Medina County, the faulting of the Balcones Fault Zone has produced a relay-ramp structure that dips to the southwest from the Edwards aquifer recharge zone and extends westward and below land surface from Seco Creek. Groundwater flow paths in the Edwards aquifer are influenced by faulting and geologic structure. Some faults act as barriers to groundwater flow paths where the aquifer is offset by 50 percent or more and result in flow moving parallel to the fault. The effectiveness of a fault as a barrier to flow changes as the amount of fault displacement changes. The structurally complex area of the Balcones Fault Zone contains relay ramps, which form in extensional fault systems to allow for deformation changes along the fault block. In Medina County, the faulting of the Balcones Fault Zone has produced a relay-ramp structure that dips to the southwest from the Edwards aquifer recharge zone. Groundwater moving down the relay ramp in northern Medina County flows downgradient (downdip) to the structural low (trough) from the northeast to the southwest. In Uvalde County, the beds dip from a structural high known as the Uvalde Salient. This results in groundwater moving from the structural high and downgradient (dip) towards a structural low (trough) to the northeast. These two opposing structural dips result in a subsurface structural low (trough) locally referred to as the Knippa Gap. This trough is located in eastern Uvalde County beneath the towns of Knippa and Sabinal. By using data that were compiled and collected for this study and previous studies, a revised map was constructed depicting the geologic framework, structure, and hydrogeologic characteristics of the Knippa Gap area in eastern Uvalde and western Medina Counties, Tex. The map also shows the interpreted structural dip directions and interpreted location of a structural low (trough) in the area known as the Knippa Gap.

  16. Impact of long-term drainage on hydrogeological and biogeochemical processes near a drainage ditch in a Canadian peatland

    NASA Astrophysics Data System (ADS)

    Kopp, B.; Fleckenstein, J.; Blodau, C.

    2009-04-01

    Little is known about long-term effects of climate change on hydrogeological and biogeochemical processes in northern peatlands. A drainage ditch in the Mer Bleue Bog, Canada which has been established around 100 years ago, was investigated as natural analogue for long-term drying due to climate change. To examine the effects of the hydrological manipulation, several piezometer nests were installed across a transect from an open bog, across the drainage ditch into a now forested bog. Forest growth likely started after lowering of the groundwater table. Piezometer nests were installed in 200, 60, 30, 15 m distance from the drainage ditch on each side; three nests were installed across the drainage ditch. Piezometers were inserted into 0.25, 0.75, 1.0, 2.0 and 3.0 m depth. Pore water samples were taken on three occasions during the study period in summer 2008 and contents of carbondioxide (CO2), methane (CH4), dissolved organic carbon (DOC), main anions and DOC quality were analysed. Water levels in each piezometer were measured every two to nine days and logger were inserted in two piezometer (depth 0.75m and 2.0m) at the 200 m sites which allowed continuous monitoring of hydraulic potentials. By ground water modelling (using the MODFLOW pre- and post-processor Groundwater Vistas) differences in ground water patterns will be elucidated. First results show higher concentrations of CO2, alongside with high concentrations of DOC and low concentrations of CH4 in the forested area, especially in the upper most 0.75 m, compared to the open bog. Together with low hydraulic conductivities (Kf) and a lower water table in the forested area, this indicates higher mineralization rates and higher decomposed peat. High chloride (Cl-) concentrations, stemming from under-lying marine clay, in the forested area suggest that lower water tables together with greater evapotranspiration (ET) result in an increased upwelling of ground water. Highest concentrations of CO2 and CH4 were determined in the ditch, alongside with medium DOC concentrations. Cl- concentrations were highest in the ditch where upwelling groundwater flow patterns occurred and important effects of the hyporheic zone are likely to take place. These first results document the importance of changes in groundwater flow patterns and drainage for hydrogeological, biogeochemical and ecological processes in northern peatlands.

  17. The hydrogeology of the Tully Valley, Onondaga County, New York: an overview of research, 1992-2012

    USGS Publications Warehouse

    Kappel, William M.

    2014-01-01

    Onondaga Creek begins approximately 15 miles south of Syracuse, New York, and flows north through the Onondaga Indian Nation, then through Syracuse, and finally into Onondaga Lake in central New York. Tully Valley is in the upper part of the Onondaga Creek watershed between U.S. Route 20 and the Valley Heads end moraine near Tully, N.Y. Tully Valley has a history of several unusual hydrogeologic phenomena that affected past land use and the water quality of Onondaga Creek; the phenomena are still present and continue to affect the area today (2014). These phenomena include mud volcanoes or mudboils, landslides, and land-surface subsidence; all are considered to be naturally occurring but may also have been influenced by human activity. The U.S. Geological Survey (USGS), in cooperation with the U.S. Environmental Protection Agency and the Onondaga Lake Partnership, began a study of the Tully Valley mudboils beginning in October 1991 in hopes of understanding (1) what drives mudboil activity in order to remediate mudboil influence on the water quality of Onondaga Creek, and (2) land-surface subsidence issues that have caused a road bridge to collapse, a major pipeline to be rerouted, and threatened nearby homes. Two years into this study, the 1993 Tully Valley landslide occurred just over 1 mile northwest of the mudboils. This earth slump-mud flow was the largest landslide in New York in more than 70 years (Fickies, 1993); this event provided additional insight into the geology and hydrology of the valley. As the study of the Tully Valley mudboils progressed, other unusual hydrogeologic phenomena were found within the Tully Valley and provided the opportunity to perform short-term, small-scale studies, some of which became graduate student theses—Burgmeier (1998), Curran (1999), Morales-Muniz (2000), Baldauf (2003), Epp (2005), Hackett, (2007), Tamulonis (2010), and Sinclair (2013). The unusual geology and hydrology of the Tully Valley, having been investigated for more than two decades, provides the basis for this report.

  18. The Union County Hydrogeology Project: Addressing Potential Imbalances by Integrating Science and Communities in Northeastern New Mexico

    NASA Astrophysics Data System (ADS)

    Zeigler, K. E.; Podzemny, B.; Peacock, G.; Yuhas, A.; Williams, S.; Yuhas, E.

    2013-12-01

    The area around the town of Clayton, in northeastern New Mexico, was not a declared groundwater basin until September of 2005. In the years leading up to 2005, battles over groundwater use and attempts to stop drilling of additional water wells for irrigation and stock use led to multiple lawsuits in the community. Because there were no regulations in place and the geology of the area had not been studied in a hydrologic framework since the 1960s, there was no basic information for decisions to be made with regards to drilling new wells and use of groundwater, leading to the potential for severe imbalances in groundwater recharge versus usage in the region. In 2006, the Northeast Soil and Water Conservation District (NESWCD), based in Clayton, decided that a large scale hydrogeology project was needed to help develop community guidelines for groundwater development. In 2010, Zeigler Geologic Consulting and the NM Bureau of Geology partnered with the NESWCD to help develop this project. The Union County Hydrogeology Project (UCHP) is unique in that this project was initially undertaken by members of the community who developed a program of biannual static water level measurements in wells across the county. In addition, the project has support from the majority of land owners in Union County and the scientists working on the project have worked closely with local community leaders to integrate this large project into everyday activities. Community integration efforts include presenting data at the Annual Producers Meeting and at the county fair, as well as other regional conferences on water use and development. Previous assumptions were that the primary aquifers being utilized were the Tertiary Ogallala Formation and the Upper Cretaceous Dakota Group. However, evaluation of surface bedrock exposures and well cuttings from petroleum exploration wells drilled in eastern Union County demonstrate that the subsurface geology is more complex than might be expected. This subsurface data, along with initial carbon-14 age determinations, water chemistry, and hydrographs from data recorders suggest that the aquifer system in Union County is partitioned and substantially more complicated than the 'oceans of water' that has often described the area.

  19. An integrated multi-scale hydrogeological model for performance and safety assessment of French geological high level and long live radwaste disposal in clay formation

    NASA Astrophysics Data System (ADS)

    Benabderrahmane, H.; Cornaton, F. J.; Kerrou, J.

    2009-12-01

    A deep geological repository of high level and long live radwaste requires sound understanding of the far field and near field groundwater flow and transport properties. Andra, French National radioactive waste management Agency is developing since last 15 years, an integrated multi-scale hydrogeological model of whole Paris basin of 200'000 Km2 area (regional scale) to produce a regional flow field associated to groundwater behavior. It includes locally the Meuse / Haute Marne clay site of about 250 Km2 area in the eastern part of Paris basin that was chosen for the emplacement of a repository. Callovo-Oxfordian as host formation is a clay layer characterized by very low permeability, a mean thickness of 130 m at about 500 m depth and is embedded by calcareous formations as aquifers (Dogger and Oxfordian). The hydrogeological conceptual model is based on stratigraphic and petrophysic modeling of the Paris basin and is accounting for the sound structural, geological, hydrogeological and geochemical data in an integrated way. At Paris basin scale, the model is a multilayer system of 27 layers (hydrogeological units) from Trias to Tertiary. A refinement at local scale of the site defines 27 hydro-geological units from Trias to Portlandian within an area of 1800 Km2. Based on sound data acquisition from borehole and seismic campaigns performed by Andra, regional faults, minor and diffuse fractures are considered. A structural and petrophysical representation of the transition zone between the Paris basin scale and site scale, as well as a better handling of surface flow boundary conditions are considered. Finite element flow and transport simulator Ground Water code (GW) is used to solve for groundwater flow at steady-state in a 1.8 Million nodes model, considering current climatic conditions. The model is calibrated against about 1250 hydraulic head measurements, and results in maximum absolute hydraulic head differences of 20 meters at the regional scale and 5 meters at the local scale. The calibrated reference model includes transmissive major faults as well as structures acting as barrier to flow. Advective-dispersive age solutions are also carried out and compared to available age dates of pore water within the two main calcareous aquifers (Dogger and Oxfordian) that embed Callovo-Oxfordian host formation, to consolidate calibration of flow and to analyze internal water mixing processes and hydraulic behavior of major faults. Lifetime expectancy solutions combined with age solutions are also used to map in the 3-D space the low- and high-speed flow zones at the local scale.

  20. Hydrogeology of and potential mining impacts on strippable lignite areas in the Denver Aquifer, east-central Colorado

    USGS Publications Warehouse

    Driver, N.E.; Williams, R.S.

    1986-01-01

    This study describes the hydrogeology of and potential impacts of mining on strippable lignite areas in the Denver aquifer in the east-central Colorado plains. Strippable lignitic coal seams , 20 to 60 ft thick, are present in the Denver Formation. The Denver aquifer, the saturated part of the Denver Formation, is likely to be affected locally by surface mining of lignite. Transmissivity of the aquifer in the study area ranges from 145 to 1,000 mg/L to the northeast in the study area as, hydraulic head decreases from 6,600 to 5,400 ft. Distance-drawdown curves show the extent of water level drawdown near a dewatered surface mine. After reclamation of the lignite mine pit, flow through the lignite spoil pile may increase the dissolved solids concentrations in the Denver aquifer. This increase could occur, because, as water from rain and overland flow percolates through the newly-exposed rock surfaces in the spoil material, minerals from the overburden can be dissolved in the water, which then joins with water from the aquifer. This increase could locally change streams, springs, and alluvial and bedrock aquifers. (USGS)

  1. Hydrogeologic framework of the diabase aquifer at the Boarhead Farms Superfund site, Bridgeton Township, Bucks County, Pennsylvania

    USGS Publications Warehouse

    Schreffler, Curtis L.

    1996-01-01

    The hydrogeologic investigation at the Boarhead Farms Superfund site was done to characterize the framework of the diabase aquifer underlying the site. The primary water-producing fracture system is less than 30 feet below land surface. Water-bearing fractures were not found deeper than 50 feet below land surface. The overburden soil is thin and ranges from 4 to 14 feet thick. The overburden soil acts as a confining unit for the underlying bedrock aquifer. Weathered bedrock consisting of broken diabase ranged from 2 to 15 feet thick, and in some areas, fractures in the weathered bedrock zone were filled with clay. Due to the clay-rich overburden soil and the thick, clay filled weathered bedrock zone, little ground-water storage is available to supply the shallow fracture systems. The diabase aquifer is low yielding with low transmissivities. Five of 15 boreholes drilled as part of the U.S. Geological Survey's investigation produced no water. Estimates of transmisivity calculated from analyses of open-hole constant-discharge tests in five boreholes ranged from 3.1 to 100 square feet per day. Estimated discharge rates for these exists between boreholes. The fracture system is limited in areal extent. Dewatering of fractures supplying water to boreholes occurred during open-hole constant-discharge tests of three boreholes.

  2. Hydrogeology of the Erunakovo region of the Kuznetsk Basin in the context of coal methane formation and mining

    SciTech Connect

    Shvartsev, S.L.; Khryukin, V.T.; Domrocheva, E.V.; Kuzevanov, K.I.; Rasskazov, N.M.; Popova, T.S.; Lepokurova, O.E.; Shvachko, E.V.

    2006-07-01

    Detailed study was given to the hydrogeology of the coal methane-promising Erunakovo region. We have established that all aquifers there are mutually related and form a single aquifer complex consisting of a series of microbeds of different water transmissivities and permeabilities. Two zones have been recognized in the Erunakovo region - of intense and slow water exchange (fresh- and brackish-water, respectively). Fresh waters with mineralization of up to 1 g/l and pH = 7 - 8 occur at depths down to about 300 m or, seldom, 500 m. Brackish waters have mineralization of 1 - 13 g/l and pH reaching 10.1. The higher mineralization is due to the higher contents of HCO{sub 3}{sup -} and Na and, sometimes, SO{sub 4}{sup 2-}, produced through sulfide oxidation, and Cl{sup -}, concentrated as a result of evaporation. In the study region, CO{sub 2} is not of mantle genesis but is the product of coal metamorphism.

  3. Remotely Piloted Aircraft Systems (RPAS) for high resolution topography and monitoring: civil protection purposes on hydrogeological contexts

    NASA Astrophysics Data System (ADS)

    Bertacchini, Eleonora; Castagnetti, Cristina; Corsini, Alessandro; De Cono, Stefano

    2014-10-01

    The proposed work concerns the analysis of Remotely Piloted Aircraft Systems (RPAS), also known as drones, UAV (Unmanned Aerial Vehicle) or UAS (Unmanned Aerial System), on hydrogeological contexts for civil protection purposes, underlying the advantages of using a flexible and relatively low cost system. The capabilities of photogrammetric RPAS multi-sensors platform were examined in term of mapping, creation of orthophotos, 3D models generation, data integration into a 3D GIS (Geographic Information System) and validation through independent techniques such as GNSS (Global Navigation Satellite System). The RPAS used (multirotor OktoXL, of the Mikrokopter) was equipped with a GPS (Global Positioning System) receiver, digital cameras for photos and videos, an inertial navigation system, a radio device for communication and telemetry, etc. This innovative way of viewing and understanding the environment showed huge potentialities for the study of the territory, and due to its characteristics could be well integrated with aircraft surveys. However, such characteristics seem to give priority to local applications for rigorous and accurate analysis, while it remains a means of expeditious investigation for more extended areas. According to civil protection purposes, the experimentation was carried out by simulating operational protocols, for example for inspection, surveillance, monitoring, land mapping, georeferencing methods (with or without Ground Control Points - GCP) based on high resolution topography (2D and 3D information).

  4. A master-slave parallel hybrid multi-objective evolutionary algorithm for groundwater remediation design under general hydrogeological conditions

    NASA Astrophysics Data System (ADS)

    Wu, J.; Yang, Y.; Luo, Q.; Wu, J.

    2012-12-01

    This study presents a new hybrid multi-objective evolutionary algorithm, the niched Pareto tabu search combined with a genetic algorithm (NPTSGA), whereby the global search ability of niched Pareto tabu search (NPTS) is improved by the diversification of candidate solutions arose from the evolving nondominated sorting genetic algorithm II (NSGA-II) population. Also, the NPTSGA coupled with the commonly used groundwater flow and transport codes, MODFLOW and MT3DMS, is developed for multi-objective optimal design of groundwater remediation systems. The proposed methodology is then applied to a large-scale field groundwater remediation system for cleanup of large trichloroethylene (TCE) plume at the Massachusetts Military Reservation (MMR) in Cape Cod, Massachusetts. Furthermore, a master-slave (MS) parallelization scheme based on the Message Passing Interface (MPI) is incorporated into the NPTSGA to implement objective function evaluations in distributed processor environment, which can greatly improve the efficiency of the NPTSGA in finding Pareto-optimal solutions to the real-world application. This study shows that the MS parallel NPTSGA in comparison with the original NPTS and NSGA-II can balance the tradeoff between diversity and optimality of solutions during the search process and is an efficient and effective tool for optimizing the multi-objective design of groundwater remediation systems under complicated hydrogeologic conditions.

  5. Transient simulations of large-scale hydrogeological processes causing temperature and salinity anomalies in the Tiberias Basin

    NASA Astrophysics Data System (ADS)

    Magri, Fabien; Inbar, Nimrod; Siebert, Christian; Rosenthal, Eliahu; Guttman, Joseph; Möller, Peter

    2015-01-01

    Hot and salty waters occur in the surroundings of the Lake Tiberias. Transient numerical simulations of thermally-driven flow without salinity effects show that mixed convection can explain the upsurge of thermal waters through permeable faults and the high temperature gradient in the Lower Yarmouk Gorge (LYG). It turns out that by including salinity effects, the flow patterns differ from those of a purely thermal regime because heavy brines dampen upward buoyant flow and convective cells. Accordingly, the fault permeability had to be increased to restore a good fit with the measured temperatures. This further supports the hypothesis that the high temperature gradient in the LYG is likely due to fractures or faults in that area. The thermohaline simulations also suggest that the derivatives of relic seawater brines are the major source of salinity. Deep brines leaching salt diapirs cannot reach the surface. However, the presence of local shallower salt bodies below the lake can potentially contribute to the salinity of the western spring and well waters, though in very small amount. This is in agreement with geochemical data according to which the major source of the brines of the Tiberias Basin represents seawater evaporation brines. Besides being of importance for understanding the hydrogeological processes that salinize Lake Tiberias, the presented simulations provide a real-case example illustrating large-scale fluid patterns due to only one source of buoyancy (heat) and those that are additionally coupled to salinity.

  6. Ground-water heat pumps: an examination of hydrogeologic, environmental, legal, and economic factors affecting their use

    SciTech Connect

    Armitage, D M; Bacon, D J; Massey-Norton, J T; Miller, J D

    1980-11-12

    Groundwater is attractive as a potential low-temperature energy source in residential space-conditioning applications. When used in conjuncton with a heat pump, ground water can serve as both a heat source (for heating) and a heat sink (for cooling). Major hydrogeologic aspects that affect system use include groundwater temperature and availability at shallow depths as these factors influence operational efficiency. Ground-water quality is considered as it affects the performance and life-expectancy of the water-side heat exchanger. Environmental impacts related to groundwater heat pump system use are most influenced by water use and disposal methods. In general, recharge to the subsurface (usually via injection wells) is recommended. Legal restrictions on system use are often stricter at the municipal and county levels than at state and Federal levels. Although Federal regulations currently exist, the agencies are not equipped to regulate individual, domestic installations. Computer smulations indicate that under a variety of climatologic conditions, groundwater heat pumps use less energy than conventional heating and cooling equipment. Life-cycle cost comparisons with conventional equipment depend on alternative system choices and well cost options included in the groundwater heat pump system.

  7. Regional flow system delineation in arid karstic basins with sparse hydrogeologic data: Cuatro Cienegas Basin, Coahuila, Mexico

    NASA Astrophysics Data System (ADS)

    Wolaver, B. D.; Sharp, J. M.; Rodriguez, J. M.

    2006-12-01

    We develop procedures for the delineation of regional groundwater flow systems in arid, karstic basins with sparse hydrogeologic data using surface topography data, geologic mapping, permeability data, chloride concentrations of groundwater and precipitation, and measured discharge data. Aquifers are characterized using geographic information systems (GIS) for groundwater catchment delineation, an analytical model for interbasin flow evaluation, a chloride balance approach for recharge estimation, and a water budget for mapping contributing catchments over a 160,000 km2 region (24.87° to 28.70° north latitude and 100.68° west to 104.75° west longitude). The study area includes the Cuatro Cienegas Basin (CCB) of Coahuila, Mexico, a National Biosphere Reserve containing springs that support groundwater-dependent ecosystems and irrigated agriculture. Sustainable groundwater development is a key issue on the U.S. Mexico border. However, these procedures may be applicable in similar settings globally. We delineate groundwater catchments that contribute local and regional groundwater discharge to CCB springs and identify a large regional flow system includes mountain recharge from as both the Sierra Madre Oriental and Occidental.

  8. Integrating indigenous ecological and scientific hydro-geological knowledge using a Bayesian Network in the context of water resource development

    NASA Astrophysics Data System (ADS)

    Liedloff, A. C.; Woodward, E. L.; Harrington, G. A.; Jackson, S.

    2013-08-01

    The contributions indigenous ecological knowledge can make to better inform water management decisions are currently undervalued leading to an underrepresentation of indigenous values in water planning and policy. This paper outlines a novel approach in which indigenous ecological knowledge informs cause and effect relationships between species and aquatic habitats to promote broader ecosystem understanding. A Bayesian Network was developed to synthesise the seasonal aquatic knowledge of a group of Gooniyandi Aboriginal language speakers, including fish species’ availability, condition and required habitat, and integrate it with hydrogeological understanding obtained from research undertaken in a stretch of the Fitzroy River, Western Australia. This river system, like most in northern Australia, is highly seasonal and entirely dependent upon groundwater for maintaining flow during prolonged dry seasons. We found that potential changes in river flow rates caused by future water resource development, such as groundwater extraction and surface water diversion, may have detrimental effects on the ability to catch the high value aquatic food species such as Barramundi and Sawfish, but also that species such as Black Bream may benefit. These findings result from changes in availability of habitats at times when Gooniyandi understanding shows they are important for providing aquatic resources in good condition. This study raises awareness of the potential outcomes of future water management and stimulates communication between indigenous people, the scientific community and water managers by developing a model of indigenous understanding from which to predict eco-hydrological change.

  9. Wave overwash impact on small islands: Generalised observations of freshwater lens response and recovery for multiple hydrogeological settings

    NASA Astrophysics Data System (ADS)

    Holding, Shannon; Allen, Diana M.

    2015-10-01

    Wave overwash events have the potential to result in severe consequences to the freshwater resources of small islands as a result of salt contamination of the aquifer. Due to the significant impact of overwash, it is important to characterise the susceptibility of small islands to these events. This study uses numerical modelling to evaluate the freshwater lens response and recovery to overwash events for various island hydrogeological settings (island types) observed worldwide. Models were developed for an example of each island type using a fully coupled surface-subsurface, density-dependent flow and solute transport modelling code. A theoretical overwash event was simulated, and the response and recovery of the freshwater lens were observed for 20 years. The freshwater lens response (degree of aquifer contamination) was largely determined by the vadose zone thickness. Lens recovery ranged from 1 to 19 years for the different island types, and was strongly affected by recharge rate. However, the recovery of potable water in the lens (and restoration of a water supply) was dominantly influenced by geological heterogeneities. The model results demonstrate the cumulative impact of the different factors affecting the freshwater lens response and recovery to the overwash event for each island type, and provide a generalised assessment of island susceptibility to overwash on a global scale, despite limited data availability for many small islands.

  10. Using hydrogeology to identify the source of groundwater to Montezuma Well, a natural spring in central Arizona: part 1

    USGS Publications Warehouse

    Johnson, Raymond H.; DeWitt, Ed H.; Arnold, L. Rick

    2012-01-01

    Montezuma Well is a natural spring located within a “sinkhole” in the desert environment of the Verde Valley in Central Arizona. It is managed by the National Park Service as part of Montezuma Castle National Monument. Because of increasing development of groundwater in the area, this research was undertaken to better understand the sources of groundwater to Montezuma Well. The use of well logs and geophysics provides details on the geology in the area around Montezuma Well. This includes characterizing the extent and position of a basalt dike that intruded a deep fracture zone. This low permeability barrier forces groundwater to the surface at the Montezuma Well “pool” with sufficient velocity to entrain sand-sized particles from underlying bedrock. Permeable fractures along and above the basalt dike provide conduits that carry deep sourced carbon dioxide to the surface, which can dissolve carbonate minerals along the transport path in response to the added carbon dioxide. At the ground surface, CO2 degasses, depositing travertine. Geologic cross sections, rock geochemistry, and semi-quantitative groundwater flow modeling provide a hydrogeologic framework that indicates groundwater flow through a karstic limestone at depth (Redwall Limestone) as the most significant source of groundwater to Montezuma Well. Additional groundwater flow from the overlying formations (Verde Formation and Permian Sandstones) is a possibility, but significant flow from these units is not indicated.

  11. Quantitative modeling and three-dimensional visualization of the petroleum hydrogeology of the Cooper & Eromanga Basins, Australia

    SciTech Connect

    Person, M.; Morin, P.; Toupin, D.; Eadington, P.

    1996-12-31

    Mathematical modeling and three-dimensional scientific visualization techniques are used in this study to reconstruct the petroleum hydrogeology of the well-studied Cooper and Eromanga Basins: Australia`s most productive on shore petroleum provinces. Our analysis focuses on the development of topography- and compaction-driven groundwater flow systems and their role on petroleum generation and migration within these basins. Finite-element models which represent groundwater flow, heat transfer, oil generation and migration were constructed along NW-SE and NE-SW cross-sectional transacts which more or less follow the present-day groundwater flow patterns through these basins. The analysis provides a quantitative reconstruction of transient fluid migration in response to tectonic processes during the past 276 million years of basin evolution. In order to compress numerical output from both cross-sectional models into a single image, quantitative results are presented in the form of evolving, three- dimensional geologic fence diagrams. Computer animation of numerical model results permit analysis of transient hydrodynamic behavior within the basin that would have been difficult or impossible to detect otherwise. Analysis of video output indicates that two episodes of regional, topography-driven groundwater flow had a pronounced effect on the thermal history of the sediments and may have important implications for petroleum generation and migration.

  12. Quantitative modeling and three-dimensional visualization of the petroleum hydrogeology of the Cooper Eromanga Basins, Australia

    SciTech Connect

    Person, M.; Morin, P. ); Toupin, D. ); Eadington, P. )

    1996-01-01

    Mathematical modeling and three-dimensional scientific visualization techniques are used in this study to reconstruct the petroleum hydrogeology of the well-studied Cooper and Eromanga Basins: Australia's most productive on shore petroleum provinces. Our analysis focuses on the development of topography- and compaction-driven groundwater flow systems and their role on petroleum generation and migration within these basins. Finite-element models which represent groundwater flow, heat transfer, oil generation and migration were constructed along NW-SE and NE-SW cross-sectional transacts which more or less follow the present-day groundwater flow patterns through these basins. The analysis provides a quantitative reconstruction of transient fluid migration in response to tectonic processes during the past 276 million years of basin evolution. In order to compress numerical output from both cross-sectional models into a single image, quantitative results are presented in the form of evolving, three- dimensional geologic fence diagrams. Computer animation of numerical model results permit analysis of transient hydrodynamic behavior within the basin that would have been difficult or impossible to detect otherwise. Analysis of video output indicates that two episodes of regional, topography-driven groundwater flow had a pronounced effect on the thermal history of the sediments and may have important implications for petroleum generation and migration.

  13. Hydrogeological characterization and assessment of groundwater quality in shallow aquifers in vicinity of Najafgarh drain of NCT Delhi

    NASA Astrophysics Data System (ADS)

    Shekhar, Shashank; Sarkar, Aditya

    2013-02-01

    Najafgarh drain is the biggest drain in Delhi and contributes about 60% of the total wastewater that gets discharged from Delhi into river Yamuna. The drain traverses a length of 51 km before joining river Yamuna, and is unlined for about 31 km along its initial stretch. In recent times, efforts have been made for limited withdrawal of groundwater from shallow aquifers in close vicinity of Najafgarh drain coupled with artificial recharge of groundwater. In this perspective, assessment of groundwater quality in shallow aquifers in vicinity of the Najafgarh drain of Delhi and hydrogeological characterization of adjacent areas were done. The groundwater quality was examined in perspective of Indian as well as World Health Organization's drinking water standards. The spatial variation in groundwater quality was studied. The linkages between trace element occurrence and hydrochemical facies variation were also established. The shallow groundwater along Najafgarh drain is contaminated in stretches and the area is not suitable for large-scale groundwater development for drinking water purposes.

  14. Hydrogeology and physical characteristics of water samples at the Red River aluminum site, Stamps, Arkansas, April 2001

    USGS Publications Warehouse

    Czarnecki, John B.; Stanton, Gregory P.; Freiwald, David A.

    2001-01-01

    The Red River Aluminum site near Stamps, Arkansas, contains waste piles of salt cake and metal byproducts from the smelting of aluminum. The waste piles are subjected to about 50 inches of rainfall a year, resulting in the dissolution of the salts and metal. To assess the potential threat to underlying ground-water resources at the site, its hydrogeology was characterized by measuring water levels and field parameters of water quality in 23 wells and at 2 surface-water sites. Seventeen of these monitor wells were constructed at various depths for this study to allow for the separate characterization of the shallow and deep ground-water systems, the calculation of vertical gradients, and the collection of water samples at different depths within the flow system. Lithologic descriptions from drill-hole cuttings and geophysical logs indicate the presence of interbedded sands, gravels, silts, and clays to depths of 65 feet. The regionally important Sparta aquifer underlies the site. Water levels in shallow wells indicate radial flow away from the salt-cake pile located near the center of the site. Flow in the deep system is to the west and southwest toward Bodcau Creek. Water-level data from eight piezometer nests indicate a downward hydraulic gradient from the shallow to deep systems across the site. Values of specific conductance (an indicator of dissolved salts) ranged from 215 to 196,200 microsiemens per centimeter and indicate that saline waters are being transported horizontally and vertically downward away from the site

  15. Construction of high-resolution stochastic geological models and optimal upscaling to a simplified layer-type hydrogeological model

    NASA Astrophysics Data System (ADS)

    Quental, Paulo; Almeida, José António; Simões, Manuela

    2012-04-01

    Despite inequalities in spatial resolution between stochastic geological models and flow simulator models, geostatistical algorithms are used for the characterisation of groundwater systems. From available data to grid-block hydraulic parameters, workflows basically utilise the development of a detailed geostatistical model (morphology and properties) followed by upscaling. This work aims to design and test a two-step methodology encompassing the generation of a high-resolution 3D stochastic geological model and simplification into a low-resolution groundwater layer-type model. First, a high-resolution 3D stochastic model of rock types or hydrofacies (sets of rock types with similar hydraulic characteristics) is generated using an enhanced version of the sequential indicator simulation (SIS) with corrections for local probabilities and for two- and three-point template statistics. In a second step, the high-resolution geological model provided by SIS is optimally simplified into a small set of layers according to a supervised simulated annealing (SA) optimisation procedure and at the end equivalent hydraulic properties are upscaled. Two outcomes are provided by this methodology: (1) a regular 2D mesh of the top and bottom limits of each hydrogeological unit or layer from a conceptual model and (2), for each layer, a 2D grid-block of equivalent hydraulic parameters prepared to be inputted into an aquifer simulator. This methodology was tested for the upper aquifer area of SPEL (Sociedade Portuguesa de Explosivos), an explosives deactivation plant in Seixal municipality, Portugal.

  16. Hydrogeological controls and indicators for oil deposits in rift grabens - An example from the Upper Rhine graben, France

    SciTech Connect

    Otto, C.J.; Toth, J. )

    1988-08-01

    The Pechelbronn petroliferous region of northeast France is located on the west side of the Upper Rhine graben between the Vosges and Black Forest Mountains. Commercial oil occurs in Mesozoic and often Tertiary lenticular, faulted formations at various depths. In areas of oil fields and along fault zones, positive temperature anomalies at shallow and great depths (geothermal gradient: 10{degree}C/100 m), high salinities (TDS > 50,000 mg/L), and anomalously high Sr{sup {minus}}, Br{sup {minus}}, and I{sup {minus}} concentrations in shallow ground waters, flowing wells, and oil/gas seeps have been observed. These phenomena may be explained by topography-induced regionally ascending cross-formational groundwater flow. This interpretation is supported by the isotopic composition of the formation waters, suggesting a meteoric origin, relatively young {sup 14}c ages ({approx} 30,000 years), and calculated flow velocities of 0.30 m/year as well as numerical modeling. Ground-water recharges in the topographic highs, converges toward the Graben basin, and discharges under artesian conditions by vertically ascending flow, preferentially along conductive faults. Vertical migration of hydrocarons is also suggested by high methane concentrations in soils observed across faults with isotope ratios indicative of thermally mature hydrocarbon gases originating at depth. Consequently, a dynamic-genetic relationship appears to exist between basinal ground-water flow, hydrocarbon accumulations, and observed natural phenomena. This relationship may be used for hydrogeological-based exploration for hydrocarbons, complementing conventional methods.

  17. Regional hydrogeological screening characteristics used for siting near-surface waste-disposal facilities in Oklahoma, U.S.A.

    USGS Publications Warehouse

    Johnson, K.S.

    1991-01-01

    The Oklahoma Geological Survey has developed several maps and reports for preliminary screening of the state of Oklahoma to identify areas that are generally acceptable or unacceptable for disposal of a wide variety of waste materials. These maps and reports focus on the geologic and hydrogeologic parameters that must be evaluated in the screening process. One map (and report) shows the outcrop distribution of 35 thick shale or clay units that are generally suitable for use as host rocks for surface disposal of wastes. A second map shows the distribution of unconsolidated alluvial and terrace-deposit aquifers, and a third map shows the distribution and hydrologic character of bedrock aquifers and their recharge areas. These latter two maps show the areas in the state where special attention must be exercised in permitting storage or disposal of waste materials that could degrade the quality of groundwater. State regulatory agencies and industry are using these maps and reports in preliminary screening of the state to identify potential disposal sites. These maps in no way replace the need for site-specific investigations to prove (or disprove) the adequacy of a site to safely contain waste materials. ?? 1991 Springer-Verlag New York Inc.

  18. MODFLOW-2000, the U.S. Geological Survey modular ground-water model -- Documentation of the Model-Layer Variable-Direction Horizontal Anisotropy (LVDA) capability of the Hydrogeologic-Unit Flow (HUF) package

    USGS Publications Warehouse

    Anderman, Evan R.; Kipp, K.L.; Hill, Mary C.; Valstar, Johan; Neupauer, R.M.

    2002-01-01

    This report documents the model-layer variable-direction horizontal anisotropy (LVDA) capability of the Hydrogeologic-Unit Flow (HUF) Package of MODFLOW-2000. The LVDA capability allows the principal directions of horizontal anisotropy to be different than the model-grid row and column directions, and for the directions to vary on a cell-by-cell basis within model layers. The HUF Package calculates effective hydraulic properties for model grid cells based on hydraulic properties of hydrogeologic units with thicknesses defined independently of the model layers. These hydraulic properties include, among other characteristics, hydraulic conductivity and a horizontal anisotropy ratio. Using the LVDA capability, horizontal anisotropy direction is defined for model grid cells within which one or more hydrogeologic units may occur. For each grid cell, the HUF Package calculates the effective horizontal hydraulic conductivity along the primary direction of anisotropy using the hydrogeologic-unit hydraulic conductivities, and calculates the effective horizontal hydraulic conductivity along the orthogonal anisotropy direction using the effective primary direction hydraulic conductivities and horizontal anisotropy ratios. The direction assigned to the model layer effective primary hydraulic conductivity is specified using a new data set defined by the LVDA capability, when active, to calculate coefficients needed to solve the ground-water flow equation. Use of the LVDA capability is illustrated in four simulation examples, which also serve to verify hydraulic heads, advective-travel paths, and sensitivities calculated using the LVDA capability. This version of the LVDA capability defines variable-direction horizontal anisotropy using model layers, not the hydrogeologic units defined by the HUF Package. This difference needs to be taken into account when designing model layers and hydrogeologic units to produce simulations that accurately represent a given field problem. This might be a reason, for example, to make model layer boundaries coincide with hydrogeologic-unit boundaries in all or part of a model grid.

  19. Hydrogeology and Water Quality of the Pepacton Reservoir Watershed in Southeastern New York. Part 3. Responses of Stream Base-Flow Chemistry to Hydrogeologic Factors and Nonpoint-Sources of Contamination

    USGS Publications Warehouse

    Heisig, Paul M.; Phillips, Patrick

    2004-01-01

    Base-flow samples were collected seasonally from 20 small streams in the 372-square-mile Pepacton Reservoir watershed to evaluate the effects of hydrogeologic factors and nonpoint sources of contamination on the chemical composition of ground-water discharge. The reservoir provides part of New York City?s water supply. The subbasins represented one of three general types of land use, each with at least 45 percent forested area (mostly on the hillsides): farmed (dairy) land, formerly farmed land with low-density residential development, or forested land with little or no development. The subbasin areas ranged from 0.38 to 10.23 square miles. All streams were sampled in December 2000 and in May, July, and October 2001. Three of the sites were designated as landuse- index sites and were sampled as many as five additional times during the study. No samples exceeded state or federal drinking-water standards for chloride, sodium, nitrate, orthophosphate, herbicides, or herbicide degradates. The chemical composition of base-flow samples was classified into major-ion water types, which were broadly defined as naturally occurring and road-salt-affected water types. About one-third of the base-flow samples were roadsalt- affected types. Natural water types were differentiated as dilute or evolved. Dilute waters have bicarbonate and sulfate as dominant anions and evolved waters have only bicarbonate as a dominant anion. Dilute water types indicate relatively short ground-water residence times or contact with unreactive aquifer material. Evolved waters have either longer ground-water residence time or contact with more reactive aquifer material than dilute ground waters. The larger subbasins with wider valley-bottom areas were more likely to have evolved water types than small subbasins with little floodplain development. Positive correlations between selected constituents and the intensity of nonpoint sources emphasize the connection between land use, shallow ground-water quality, and stream base-flow water quality. Chloride and sodium, which are relatively conservative constituents, showed strong linear relations with annual estimates of road-salt application during all four sampling periods. Nonconservative constituents, such as the nutrients nitrate and orthophosphate, showed linear relations with manure production rate among farmed basins, but only at specific times of the year because of losses through biologic activity. Nitrate showed the strongest relation in winter because losses to biological activity were at a minimum. Orthophosphate showed the strongest relation in early summer, when hydrologic and chemical conditions appear to favor release from sediments. Atmospheric nitrogen deposition is an additional source of nitrogen that can be released from mature or stressed forested basins. Detections of herbicides (atrazine, metolachlor, simazine) and herbicide degradates ( Metolachlor ESA, alachlor ESA, deethylatrazine) in base flow were closely correlated with subbasins in which corn was grown during the study. Atrazine was detected at the farmed index site only in early summer, after application and two rain storms. This detection corresponded to the peak orthophosphate concentration. In contrast, metolachlor ESA was detected in nearly all farmedindex- subbasin samples and peaked in late summer, when percent base-flow contributions from farmed valley-bottom areas were likely highest. The implications of this study are that seasonal and more frequent base-flow surveys of water chemistry from small stream basins can help refine the understanding of local hydrogeologic systems and define the effects of nonpointsource contamination on base-flow water quality. The concentration of most nonpoint sources in valley-bottom or lower-hillside areas helped indicate the relative contributions of water from hillside and valley-bottom areas at different times of year. The positive correlations between the intensity of nonpoint-

  20. Hydrogeology and simulated effects of ground-water withdrawals for citrus irrigation, Hardee and De Soto counties, Florida

    USGS Publications Warehouse

    Metz, P.A.

    1995-01-01

    The hydrogeology of Hardee and De Soto Counties in west-central Florida was evaluated, and a ground-water flow model was developed to simulate the effects of expected increases in ground-water withdrawals for citrus irrigation on the potentiometric surfaces of the intermediate aquifer system and the Upper Floridan aquifer. In 1988, total citrus acreage in Hardee and De Soto Counties was 89,041 acres. By the year 2020, citrus acreage is projected to increase to 130,000 acres. Ground water is the major source of water supply in the study area, and 94 percent of the ground-water withdrawn in the area is used for irrigation purposes. The principal sources of ground water in the study area are the surficial aquifer, the intermediate aquifer system, and upper water-yielding units of the Floridan aquifer system, commonly referred to as the Upper Floridan aquifer. The surficial aquifer is a permeable hydrogeo1ogic unit contiguous with land surface that is comprised predominately of surficial quartz sand deposits that generally are less than 100 feet thick. The intermediate aquifer system is a somewhat less permeable hydrogeologic unit that lies between and retards the exchange of water between the overlying surficial aquifer and the underlying Upper Floridan aquifer. Thickness of the intermediate aquifer system ranges from about 200 to 500 feet and transmissivity ranges from 400 to 7,000 feet squared per day. The highly productive Upper Floridan aquifer consists of 1,200 to 1,400 feet of solution-riddled and fractured limestone and dolomite. Transmissivity values for this aquifer range from 71,000 to 850,000 feet squared per day. Wells open to the Upper Floridan aquifer. the major source of water in the area, can yield as much as 2,500 gallons of water per minute. The potential effects of projected increases in water withdrawals for citrus irrigation on groundwater heads were evaluated by the use of a quasi-three-dimensional, finite-difference, ground-water flow model. The model was calibrated under steady-state conditions to simulate September 1988 heads and under transient conditions to simulate head fluctuations between September 1988 and September 1989. The calibrated model was then used to simulate hydraulic heads for the years 2000 and 2020 that might result from projected increases in pumpage for citrus irrigation. The model simulation indicated that increased pumpage might be expected to result in: A maximum decline of more than 10 feet in theintermediate aquifer system at a proposed grove in eastern De Soto County and an average decline of more than 2 feet in much of the study area. An increase in downward leakage to the intermediate aquifer system from the overlying surficial aquifer system from 178 to 183 million gallons per day. A decrease in upward leakage from the intermediate aquifer system to the surficial aquifer from 1.58 to 1.47 million gallons per day. A maximum decline of about 5 feet in the Upper Floridan aquifer at a proposed grove in eastern De Soto County and a decline of more than 2 feet in much of the model area. An increase in downward leakage to the Upper Floridan aquifer from the intermediate aquifer system from 180 to 183 million gallons per day. A decrease in upward leakage from the Upper Floridan aquifer to the intermediate aquifer system from 4.32 million gallons per day in 1989 to 3.89 million gallons per day in the year 2,000. but an increase in upward leakage to 5.10 million gallons per day by the year 2020, reflecting a change in hydraulic gradient.

  1. Hydrogeology and extent of saltwater intrusion of the Great Neck peninsula, Great Neck, Long Island, New York

    USGS Publications Warehouse

    Stumm, Frederick

    2001-01-01

    Great Neck, a peninsula, in the northwestern part of Nassau County, N.Y., is underlain by unconsolidated deposits that form a sequence of aquifers and confining units. Seven public-supply wells have been affected by the intrusion of saltwater from the surrounding embayments (Little Neck Bay, Long Island Sound, Manhasset Bay). Fifteen observation wells were drilled in 1991-96 for the collection of hydrogeologic, geochemical, and geophysical data to delineate the subsurface geology and extent of saltwater intrusion within the peninsula. Continuous high-resolution seismic-reflection surveys in the embayments surrounding the Great Neck peninsula and the Manhasset Neck peninsula to the east were completed in 1993 and 1994. Two hydrogeologic units are newly proposed herein.the North Shore aquifer and the North Shore confining unit. The new drill-core data collected in 1991-96 indicate that the Lloyd aquifer, the Raritan confining unit, and the Magothy aquifer have been completely removed from the northern part of the peninsula by extensive glacial erosion. Water levels at selected observation wells were measured quarterly throughout the study. The results from two studies of the effects of tides on ground-water levels in 1992 and 1993 indicate that water levels at wells screened within the North Shore and Lloyd aquifers respond to tides and pumping effects, but those in the overlying upper glacial aquifer (where the water table is located) do not. Data from quarterly water-level measurements and the tidal-effect studies indicate the North Shore and Lloyd aquifers to be hydraulically connected. Offshore seismic-reflection surveys in the surrounding embayments indicate at least two glacially eroded buried valleys with subhorizontal, parallel reflectors indicative of draped bedding that is interpreted as infilling by silt and clay. The buried valleys (1) truncate the surrounding coarse-grained deposits, (2) are asymmetrical and steep sided, (3) trend northwest-southeast, (4) are 2-4 miles long and about 1 mile wide, and (5) extend to more than 200 feet below sea level. Water from six public-supply wells screened in the Magothy and upper glacial aquifers contained volatile organic compounds in concentrations above the New York State Department of Health Drinking Water Maximum Contaminant Levels, as did water from one public-supply well screened in the Lloyd aquifer, and from three observation wells screened in the upper glacial and Magothy aquifers. Four distinct wedge-shaped areas of saltwater intrusion have been delineated within the aquifers in Great Neck; three areas extend into the Lloyd and North Shore aquifers, and the fourth area extends into the upper glacial aquifer. Three other areas of saltwater intrusion also have been detected. Borehole-geophysical-logging data indicate that four of these saltwater wedges range from 20 to 125 feet in thickness and have sharp freshwater-saltwater interfaces, and that maximum chloride concentrations in 1996 ranged from 141 to 13,750 milligrams per liter. Seven public-supply wells have either been shut down or are currently being affected by saltwater intrusion.

  2. A new hydrogeological model of charging shallow and deep aquifers in the Lake Neusiedl - Seewinkel region (Northern Burgenland, Austria)

    NASA Astrophysics Data System (ADS)

    Häusler, Hermann; Müllegger, Christian; Körner, Wilfried; Ottner, Franz; Prohaska, Thomas; Irrgeher, Johanna; Tchaikovsky, Anastassiya; Dober, Gregor; Gritzmann, Romana; Mykhaylyuk, Ivanna

    2014-05-01

    The hypothesis of ascending thermal groundwater in the Seewinkel was introduced by Tauber (1965), favoured by Schmid (1970), and followed up by Wurm (2000). The main idea of this hypothesis was up welling of saline waters from a deep aquifer along faults, which in the 1950s have been identified as such in seismic sections. An aquifer of marine deposits of Badenian to Sarmatian age was postulated as source, and hydrochemical composition of water should have changed during migration due to high contents of sodium carbonate and sulphate instead of potassium chloride in the shallow groundwater bodies of the Seewinkel. Häusler (2010) argued, however, that fault aquifers discharging saline waters nowhere have been identified in this region. Supposed that according to the ascendance hypothesis ion composition of up welling formation water could have undergone a change, the primary isotope signal of marine water should have not. In order to get a better insight to the groundwater cycle we compare results from geochemical analyses, clay mineralogical analyses, and leachates of source rocks of potential recharge areas with respective analyses of shallow and deep aquifers, and apply the method of stable hydroisotopes such as oxygen, deuterium, strontium and chloride for distinguishing origin of groundwaters. We evaluate the hypothesis of up welling connate waters, and eventually come up with a new conceptual hydrogeological model for the Neusiedl-Seewinkel region regarding composition, origin, flow direction and residence time of groundwater in shallow and deeper aquifers. The very low value of -12.26‰ for oxygen isotope ratio of thermal groundwater from the deepest aquifer drilled to a depth of about 1000 metres at Frauenkirchen in northern Seewinkel, which is not highly mineralised, excludes connate water as major source, which basically is characterized by high oxygen isotope ratio values. Taking into account that oxygen isotope ratio-values ranging from -12.0‰ to -10.5‰ in the catchment of Lake Neusiedl are characteristic for waters derived from the cooler period of the Pleistocene (Rank et al., 1982), we conclude that groundwater of the deepest aquifer of the Seewinkel is not of Badenian to Sarmatian age but only several tens of thousands of years old. The artesian wells of the Seewinkel region drilled down to several hundreds of metres yielded groundwater with oxygen isotope ratio-values ranging between -11.90‰ and -10.83‰, values fitting well to waters of Pleistocene age of that region. Since wells discharging the Leitha Mountains also revealed oxygen isotope ratio-values varying from -11.10‰ to -10.22‰, we conclude that the mountain chains surrounding Lake Neusiedl basically charged both shallow and deeper aquifers of the Seewinkel. From oxygen isotope ratios of these groundwater bodies we therefore conclude that first the majority of aquifers of the Lake Neusiedl region was charged from the surrounding mountain chains, and second that salinity of soils in the Seewinkel region cannot be derived from up welling connate water, as has been proofed for Lake Kelemenszék area south of Budapest (Simon et al., 2011). There is no doubt on the fact, however, that differing amounts of free carbon dioxide in several aquifers of the Seewinkel region originate from deep-seated post volcanic activity in this region. Häusler, H. (2010)(ed.): Geologische Karte der Republik Österreich 1:50.000, Erläuterungen zur Geologischen Karte 78 Rust.- 191 S., 65 Abb., 5 Tab., 2 Taf., (Geologische Bundesanstalt), Wien. Rank, D., Rajner, V., Staudner, F. and Papesch, W. (1982): Zur Altersdatierung der Grundwässer am Ostufer des Neusiedlersees.- BFB-Bericht, 43, 197-204, 2 Abb., (Biologisches Forschungsinstitut für Burgenland), Illmitz. Simon, S., Mádl-Sz?nyi, J., Müller, I. and Pogácsás, G. (2011): Conceptual model for surface salinization in an overpressured and a superimposed gravity-flow field, Lake Kelemenszék area, Hungary.- Hydrogeology Journal, 19, 701-717. Tauber, A. F. (1965): Geologische Typologie und Genese der Miner

  3. Hydrogeologic data for existing excavations and the Area 5 Radioactive Waste Management Site, Nevada Test Site, Nye County, Nevada

    SciTech Connect

    Not Available

    1993-12-01

    The Special Projects Section of Reynolds Electrical & Engineering Co., Inc. is responsible for characterizing the subsurface geology and hydrology of the Area 5 Radioactive Waste Management Site (RWMS) at the Nevada Test Site (NTS) for the US Department of Energy, Nevada Operations Office (DOE/NV), Office of Environmental Restoration and Waste Management Waste Management Division. Geologic description, in situ testing, and laboratory analyses of alluvium exposed in existing excavations are important subparts to the Area 5 Site Characterization Program designed to determine the suitability of the RWMS for disposal of low level waste mixed waste and transuranic waste. The primary purpose of the Existing Excavation Project is two-fold: first, to characterize important hydrologic properties of the near surface alluvium, thought to play an important role in the infiltration and redistribution of water and solutes through the upper unsaturated zone at the Area 5 RWMS; and second, to provide guidance for the design of future sampling and testing programs. The justification for this work comes from the state of Nevada review of the original DOE/NV Part B Permit application submitted in 1988 for disposal of mixed wastes at the RWMS. The state of Nevada determined that the permit was deficient in characterization data concerning the hydrogeology of the unsaturated zone. DOE/NV agreed with the state and proposed the study of alluvium exposed in existing excavations as one step toward satisfying these important site characterization data requirements. Other components of the site characterization process include the Science Trench Borehole and Pilot Well Projects.

  4. Applications of Ground Penetrating Radar for Hydrogeologic Characterization at the P Reactor Area, Savannah River Site, South Carolina

    NASA Astrophysics Data System (ADS)

    Cameron, A. E.; Knapp, C. C.; Addison, A.; Waddell, M.

    2006-12-01

    Ground Penetrating Radar (GPR) techniques were implemented at Savannah River Site (SRS), South Carolina, in order to develop new approaches for hydrogeophysical characterization in heterogeneous environments. The study site is the P Reactor Area located within the Upper Atlantic Coastal Plain, with clastic sediments ranging from Late Cretaceous to Miocene age. Lithologies consist of sand, clayey sand, and clay with minor amounts of calcareous minerals. Increasing interest in the P Reactor Area in recent years is the result of the presence of several contaminant plumes including trichloroethylene (TCE) that originates from the northwest section of the reactor facility and discharges into nearby Steel Creek. Here, we present the results from subsurface characterization using the GPR technique involving the PulseEKKO 100 GPR system with 50, 100, and 200 MHz antennas. Data acquisition included (1) several regional 2D common-offset GPR transects for general stratigraphic characterization, (2) a series of common-mid point (CMP) profiles for velocity estimation, (3) a set of vertical radar profiles (VRP) at an existing borehole in the vicinity of the study area, and (4) a 3D GPR survey for detailed subsurface lithostratigraphic characterization collected with the 50 MHz antenna. The ongoing GPR processing will map key dielectric interfaces from the ground surface to ~20 meters, and will be integrated with co-located surface and vertical seismic reflection data as well as with lithologic information obtained from Cone Penetrometer Technology (CPT) tests performed at the study area. This lithosptratigraphic zonation will provide the framework for subsequent hydrological parameter estimation, which will be performed using borehole hydrogeological and crosshole seismic and GPR methods. This research was supported by the Office of Science (BER), U.S. Department of Energy, Grant No. DE-FG02-06ER64210.

  5. Petroleum hydrogeology of the Cooper and Eromanga basins, Australia: Some insights from mathematical modeling and fluid inclusion data

    SciTech Connect

    Toupin, D.; Morin, P.; Eadington, P.J.

    1997-04-01

    Mathematical modeling and fluid inclusion data analysis are used to reconstruct the petroleum hydrogeology of the Australian Cooper and Eromanga basins. Our analysis focuses on the development of topography- and compaction-driven groundwater flow systems and their role in heat redistribution, petroleum generation, and oil and brine migration during basin evolution. Finite-element models of basin transport processes are constructed along northeast-southwest (AA{prime}) and northwest-southeast (BB{prime}) cross sections that generally follow the present-day groundwater flow patterns through these basins. Numerical results are presented in the form of three-dimensional evolving geologic fence diagrams. The most significant feature of basin paleohydrology was the development of topography-driven flow systems associated with two separate mountain-building events during the Tertiary and Pliocene-Holocene. Computed convective heat transfer effects resulting from these paleogroundwater flow systems produced thermal anomalies as high as 40{degrees}C in recharge and discharge areas, causing source beds to attain peak oil generation in some areas. Computed oil heads also suggest that the Tertiary flow system may have focused oil migration in Eromanga carrier beds for hundreds of kilometers toward structural traps overlying the southern end of the Cooper basin. Computed saltwater heads indicate that the Tertiary and, to a lesser extent, the Pliocene-Holocene topography-driven flow systems probably also were responsible for flushing basinal brines out of the Copper basin. Quantitative results are consistent with {sup 36}Cl groundwater age measurements, vitrinite reflectance data, present-day geothermal gradient and groundwater salinity data, fluid inclusion paleosalinity data, and the location of proven oil reserves in the southern Cooper basin.

  6. Hydrogeologic framework of the shallow ground-water system in the Cox Hall Creek basin, Cape May County, New Jersey

    USGS Publications Warehouse

    Lacombe, Pierre J.; Zapecza, Otto S.

    2006-01-01

    Cape May County is investigating the feasibility of restoring the lowermost reach of Cox Hall Creek to its former state as a tidal saltwater wetland; however, the potential for contamination of the shallow ground-water system, which provides water to hundreds of nearby privately owned domestic wells, with saltwater from the restored wetland is of particular concern. To evaluate the potential effectiveness and risks of restoring the saltwater wetlands, the County needs information about the hydrogeologic framework in the area, and about the potential vulnerability of the domestic wells to contamination. The shallow ground-water system in the Cox Hall Creek area consists of unconsolidated Holocene and Pleistocene deposits. The Holly Beach water-bearing zone, the unconfined (water-table) aquifer, is about 35 feet thick and contains a 2- to 4-foot-thick clay lens about 10 feet below land surface; a lower, more discontinuous clay lens about 30 to 35 feet below land surface ranges up to 5 feet in thickness. A 75-foot-thick confining unit separates the Holly Beach water-bearing zone from the underlying estuarine sand aquifer. The clay lenses in the Holly Beach water-bearing zone likely retard the movement of contaminants from septic tanks, lawns, and other surficial sources, protecting wells that tap the lower, sandy part of the aquifer. The clay lenses also may protect these wells from salty surface water if withdrawals from the Holly Beach water-bearing zone are not increased substantially. Deeper wells that tap the estuarine sand aquifer are more effectively protected from saltwater from surface sources because of the presence of the overlying confining unit.

  7. Ring of Cenotes (sinkholes), northwest Yucatan, Mexico: Its hydrogeologic characteristics and possible association with the Chicxulub impact crater

    NASA Astrophysics Data System (ADS)

    Perry, Eugene; Marin, Luis; McClain, Jana; Velazquez, Guadalupe

    1995-01-01

    A 180-km-diameter semicircular band of abundant karst sinkholes (Ring of Cenotes) in northwest Yucatan, Mexico, coincides approximately with a concentric ring of the buried Chicxulub structure, a circular feature manifested in Cretaceous and older rocks, that has been identified as the product of the impact of a bolide. The ring, expressed in Tertiary rocks, marks a zone of high permeability as shown by (1) the sinkholes themselves, (2) breaks in the coastal dune system and high density of springs where the ring intersects the coast, and (3) water-level transects characterized by a decline in water level toward the ring. Any direct relation that exists between the Ring of Cenotes and the Chicxulub structure bears on regional hydrogeology. If the layer or zone responsible for the ring is deeply buried, it may act as a barrier to the movement of ground water across the main flow direction. Shallower zones of horizontal permeability could result in less complete diversion of ground water. Through its influence on Yucatan aquifer characteristics, the ring may provide a link between modern environmental problems and astrogeology. Possible origins for the Ring of Cenotes are (1) faulting, perhaps reactivated by post-Eocene mid-Miocene basin loading, (2) permeability in a buried reef complex developed in the shallow Paleocene sea around the crater rim, or (3) breccia collapse occasioned by consolidation or by solution of evaporite components. If the ring developed on ancient faults, it may outline hydrothermal systems and mineral deposits produced during Paleocene cooling of the Chicxulub melt sheet.

  8. Hydrogeology of a young moraine area in NE Germany: Testing hypotheses on subsurface structures with an iterative groundwater modeling approach

    NASA Astrophysics Data System (ADS)

    Wilke, Henriette; Tecklenburg, Christina; Güntner, Andreas; Blume, Theresa

    2015-04-01

    Investigating subsurface structures and properties of young moraine areas is a challenging task due to the heterogeneity of the subsurface combined with limited possibilities of outcrop characterization. To overcome this challenge we suggest a multi-method approach that merges a variety of geophysical, hydrochemical and hydrogeological monitoring data with iterative hypothesis-based modeling of groundwater dynamics. The focus area of this study is the region of Lake Fürstenseer See, which is located in a young moraine area in the terminal moraine and outwash plain area of the last glacial maximum (Pomeranian) in Mecklenburg-Vorpommern, north-eastern Germany. The assumed main control on groundwater flow paths of the uppermost aquifer in this region is the depth and the "topography" of the first aquiclude. The groundwater flow model Visual MODFLOW Pro was parameterized based on average hydraulic properties determined from core samples taken during observation well drilling. In a first hypothesis the depth of the aquiclude was assumed to be uniform over the entire region. Data from a nearby climate station was used as input, while well water level dynamics in 23 observation wells and lake water level dynamics were used for validation. In a second iteration, the depth of the aquiclude which was identified at 20 of the wells was interpolated over the area. The resulting groundwater flow paths and dynamics were re-evaluated. In a final step, data from ERT investigations along several transects throughout the area was also included in the interpolation of the depth of the aquiclude. While groundwater dynamics can be evaluated directly by comparison with the observed dynamics at the observation wells, groundwater flow paths are evaluated a) based on the observed differences in water chemistry including isotopic composition at the observation wells and b) based on the observed spatial patterns of groundwater inflow into the lake, which were identified both by lake sediment temperature profiles and an extensive network of piezometers along the shore.

  9. Tectonic Speleogenesis of Devils Hole, Nevada, and Implications for Hydrogeology and the Development of Long, Continuous Paleoenvironmental Records

    USGS Publications Warehouse

    Riggs, A.C.; Carr, W.J.; Kolesar, Peter T.; Hoffman, R.J.

    1994-01-01

    Devils Hole, in southern Nevada, is a surface collapse into a deep, planar, steeply dipping fault-controlled fissure in Cambrian limestone and dolostone. The collapse intersects the water table about 15 m below land surface and the fissure extends at least 130 m deeper. Below water, most of the fissure is lined with a >30-cm-thick layer of dense maxillary calcite that precipitated continuously from groundwater for >500,000 yr. The thick mammillary calcite coat implies a long history of calcite-supersaturated groundwaters, which, combined with the absence of dissolutional morphologies, suggests that Devils Hole was not formed by karst processes. Devils Hole is located in a region of active extension; its tectonic origin is shown by evidence of spreading of its planar opening along a fault and by the orientation of its opening and others nearby, perpendicular to the northwest-southeast minimum principal stress direction of the region. Most Quaternary tectonic activity in the area, including seismicity and Quaternary faults and fractures, occurs on or parallel to northeast-striking structures. The hydrogeologic implications of this primarily structural origin are that fracture networks and caves opened by extensional tectonism can act as groundwater flowpaths functionally similar to those developed by karst processes and that, during active extension, transmissivity can be maintained despite infilling by mineral precipitation. Such extensional environments can provide conditions favorable for accumulation of deposits preserving long, continuous paleoenvironmental records. The precipitates in Devils Hole store chronologies of flow system water-level fluctuations, hydrochemistry, a half-million-yr proxy paleoclimate record, evidence of Devils Hole's tectonic origin, and probably atmospheric circulation.

  10. Tectonic Speleogenesis of Devils Hole, Nevada, and Implications for Hydrogeology and the Development of Long, Continuous Paleoenvironmental Records

    NASA Astrophysics Data System (ADS)

    Riggs, Alan C.; Carr, W. J.; Kolesar, Peter T.; Hoffman, Ray J.

    1994-11-01

    Devils Hole, in southern Nevada, is a surface collapse into a deep, planar, steeply dipping fault-controlled fissure in Cambrian limestone and dolostone. The collapse intersects the water table about 15 m below land surface and the fissure extends at least 130 m deeper. Below water, most of the fissure is lined with a >30-cm-thick layer of dense maxillary calcite that precipitated continuously from groundwater for >500,000 yr. The thick mammillary calcite coat implies a long history of calcite-supersaturated groundwaters, which, combined with the absence of dissolutional morphologies, suggests that Devils Hole was not formed by karst processes. Devils Hole is located in a region of active extension; its tectonic origin is shown by evidence of spreading of its planar opening along a fault and by the orientation of its opening and others nearby, perpendicular to the northwest-southeast minimum principal stress direction of the region. Most Quaternary tectonic activity in the area, including seismicity and Quaternary faults and fractures, occurs on or parallel to northeast-striking structures. The hydrogeologic implications of this primarily structural origin are that fracture networks and caves opened by extensional tectonism can act as groundwater flowpaths functionally similar to those developed by karst processes and that, during active extension, transmissivity can be maintained despite infilling by mineral precipitation. Such extensional environments can provide conditions favorable for accumulation of deposits preserving long, continuous paleoenvironmental records. The precipitates in Devils Hole store chronologies of flow system water-level fluctuations, hydrochemistry, a half-million-yr proxy paleoclimate record, evidence of Devils Hole's tectonic origin, and probably atmospheric circulation.

  11. A multidisciplinary geological and geophysical approach to define structural and hydrogeological implications of the Molinaccio spring (Spello, Italy)

    NASA Astrophysics Data System (ADS)

    Ercoli, Maurizio; Pauselli, Cristina; Forte, Emanuele; Di Matteo, Lucio; Mazzocca, Massimiliano; Frigeri, Alessandro; Federico, Costanzo

    2012-02-01

    In this paper, a multidisciplinary geological and geophysical approach has been applied in the complex area of Molinaccio spring (Spello, Umbria, Central Italy) to: 1) understand the large-scale geologic and tectonic structure of the area; 2) define the hydrogeological behavior of the various formations in relationship with the identified structural elements; 3) highlight at small-scale the tectonic structures and their relationships with the water caption tunnel, which is the draining structure of a still working, ancient Roman aqueduct giving water to the village of Spello and to the surrounding plain. Our approach includes different techniques like Ground Penetrating Radar (GPR) and Electrical Resistivity Tomography (ERT), direct geological investigations, archaeological studies, GIS data collection and integration. The GPR data revealed, in the area of the water-caption tunnel, two main tectonic structures, both also confirmed by ERT data: the presence of a zone (maximum 2 m wide), interpreted as a normal fault area and an overthrust that puts in contact the permeable Scaglia Rossa limestone (Early Turonian-Middle Eocene), and the Scaglia Variegata-Cinerea marly limestones (Middle Eocene-Upper Oligocene) on the footwall, characterized by lower hydraulic permeability. Using some rough information available on the sub-surface path of the tunnel, that shows a sharp bend after a long straight course, together with the geophysical images, was possible to describe how Romans built the tunnel: they probably followed the wet outcropping rock during the excavation, and changed abruptly the dig direction when they intercepted the normal fault area, aligning then the excavation along its strike. This latter result is important also because recently a multidisciplinary project has been developed to restore and exploit the entire water supply structure, which is not only a well-preserved example of Roman remains with high archaeological value, but also a vital infrastructure for a zone with great tourist potential.

  12. Hydrogeologic setting, hydraulic properties, and ground-water flow at the O-Field area of Aberdeen Proving Ground, Maryland

    USGS Publications Warehouse

    Banks, W.S.; Smith, B.S.; Donnelly, C.A.

    1996-01-01

    The U.S. Army disposed chemical agents, laboratory materials, and unexploded ordnance at O-Field in the Edgewood area of Aberdeen Proving Ground, Maryland, from before World War II until at least the 1950's. Soil, ground water, surface water,and wetland sediments in the O-Field area were contaminated from the disposal activity. A ground-water-flow model of the O-Field area was constructed by the U.S. Geological Survey (USGS) in 1989 to simulate flow in the central and southern part of the Gunpowder Neck. The USGS began an additional study of the contamination in the O-Field area in cooperation with the U.S. Army in 1990 to (1) further define the hydrogeologic framework of the O-Field area, (2) characterize the hydraulic properties of the aquifers and confining units, and (3) define ground-water flow paths at O-Field based on the current data and simulations of ground-water flow. A water-table aquifer, an upper confining unit, and an upper confined aquifer comprise the shallow ground-water aquifer system of the O-Field area. A lower confining unit, through which ground-water movement is negligible, is considered a lower boundary to the shallow aquifer system. These units are all part of the Pleistocene Talbot Formation. The model developed in the previous study was redesigned using the data collected during this study and emphasized New O-Field. The current steady-state model was calibrated to water levels of June 1993. The rate of ground-water flow calculated by the model was approximately 0.48 feet per day (ft/d) and the rate determined from chlorofluorocarbon dates was approximately 0.39 ft/d.

  13. Hydrogeology and simulation of ground-water flow at Arnold Air Force Base, Coffee and Franklin counties, Tennessee

    USGS Publications Warehouse

    Haugh, C.J.; Mahoney, E.N.

    1994-01-01

    The U.S. Air Force at Arnold Air Force Base (AAFB), in Coffee and Franklin Counties, Tennessee, is investigating ground-water contamination in selected areas of the base. This report documents the results of a comprehensive investigation of the regional hydrogeology of the AAFB area. Three aquifers within the Highland Rim aquifer system, the shallow aquifer, the Manchester aquifer, and the Fort Payne aquifer, have been identified in the study area. Of these, the Manchester aquifer is the primary source of water for domestic use. Drilling and water- quality data indicate that the Chattanooga Shale is an effective confining unit, isolating the Highland Rim aquifer system from the deeper, upper Central Basin aquifer system. A regional ground-water divide, approximately coinciding with the Duck River-Elk River drainage divide, underlies AAFB and runs from southwest to northeast. The general direction of most ground-water flow is to the north- west or to the northwest or to the southeast from the divide towards tributary streams that drain the area. Recharge estimates range from 4 to 11 inches per year. Digital computer modeling was used to simulate and provide a better understanding of the ground-water flow system. The model indicates that most of the ground-water flow occurs in the shallow and Manchester aquifers. The model was most sensitive to increases in hydraulic conductivity and changes in recharge rates. Particle-tracking analysis from selected sites of ground-water contamination indicates a potential for contami- nants to be transported beyond the boundary of AAFB.

  14. Geogenic Cr oxidation on the surface of mafic minerals and the hydrogeological conditions influencing hexavalent chromium concentrations in groundwater.

    PubMed

    Kazakis, N; Kantiranis, N; Voudouris, K S; Mitrakas, M; Kaprara, E; Pavlou, A

    2015-05-01

    This study aims to specify the source minerals of geogenic chromium in soils and sediments and groundwater and to determine the favorable hydrogeological environment for high concentrations of Cr(VI) in groundwaters. For this reason, chromium origin and the relevant minerals were identified, the groundwater velocity was calculated and the concentrations of Cr(VI) in different aquifer types were determined. Geochemical and mineralogical analyses showed that chromium concentrations in soils and sediments range from 115 to 959 mg/kg and that serpentine prevails among the phyllosilicates. The high correlation between chromium and serpentine, amphibole and pyroxene minerals verifies the geogenic origin of chromium in soils and sediments and, therefore, in groundwater. Manganese also originates from serpentine, amphibole and pyroxene, and is strongly correlated with chromium, indicating that the oxidation of Cr(III) to Cr(VI) is performed by manganese-iron oxides located on the surface of Cr-Mn-rich minerals. Backscattered SEM images of the soils revealed the unweathered form of chromite grains and the presence of Fe-Mn-rich oxide on the outer surface of serpentine grains. Chemical analyses revealed that the highest Cr(VI) concentrations were found in shallow porous aquifers with low water velocities and their values vary from 5 to 70 ?g/L. Cr(VI) concentrations in ophiolitic complex aquifers ranged between 3 and 17 ?g/L, while in surface water, karst and deeper porous aquifers, Cr(VI) concentrations were lower than the detection limit of 1.4 ?g/L. PMID:25666283

  15. Hydraulic behavior of two areas of the Floridan aquifer system characterized by complex hydrogeologic settings and large groundwater withdrawals

    SciTech Connect

    Maslia, M.L. )

    1993-03-01

    Two areas of the Florida aquifer system (FAS) that are characterized by complex hydrogeologic settings and exceedingly large ground-water withdrawals are the Dougherty Plain area of southwest GA and the Glynn County area of southeast GA. In southwest GA, large scale withdrawals of ground water for agricultural and livestock irrigation amounted to about 148 million gallons per day (mg/d) during 1990. Large scale pumping in Glynn County, primarily used for industrial purposes and centered in the City of Brunswick, amounted to about 88 mg/d during 1990. In southwest GA, the FAS consists primarily of the Ocala Limestone (OL) of late Eocene age. Confining the aquifer from above is a residual layer (50 ft thick) of sand and clay containing silicified boulders which is derived from the chemical weathering of the OL. This area is characterized by karst topography marked by numerous depressions and sinkholes, high transmissivity (generally greater than 50,000 feet squared per day), and significant hydraulic connections to overlying streams and lakes. These characteristics, along with the seasonal nature of pumping and mean annual recharge of about 10 inches per year have prevented permanent, long-term water-level declines. In the Glynn County area, the FAS can be more than 2,600 ft thick, consisting of a sequence of calcareous and dolomitic rocks that are of Late Cretaceous to early Miocene in age. The aquifer system is confined above by clastic rocks of Middle Miocene age, having an average thickness of 400 ft. This area is characterized by post-depositional tectonic modification of the subsurface as opposed to simple karst development, thick confinement of the aquifer system, and significant amounts of vertical leakage of water from below. These characteristics and heavy-long term pumping from the Upper Floridan aquifer (UFA) have caused a broad, shallow cone of depression to develop and the upward migration of saltwater to contaminate the freshwater zones of the UFA.

  16. A Tree Diagram: Compilation of Methods for Evaluating Host Rock Suitability Taking Account of Uncertainties in Hydrogeological Modeling

    NASA Astrophysics Data System (ADS)

    Sawada, A.; Hayano, A.; Goto, J.; Inagaki, M.

    2014-12-01

    In Japan, the siting process of geological repositories for vitrified high-level radioactive waste and low-level radioactive waste containing long-lived nuclides shall comprise step-wise site investigations and evaluations. The Detailed Investigation Areas will be selected focusing on the suitability for the host rock where the underground facility is constructed, after a series of surface-based investigations at Preliminary Investigation Areas. The suitability shall be judged by considering multi-disciplinary performances of the rock mass, such as thermal, hydrologic, mechanical and geochemical conditions and the volume of rock mass, based on the site models. However, the limited geoscientific information yields relatively large uncertainties of the site models, especially the hydrogeological models due to a wider variability of hydraulic properties. The uncertainties make it difficult to clarify the relationship among the site investigation, repository design (Design) and safety assessment (SA). In this study, groundwater travel time is identified as one of the important evaluation factors relevant for SA in terms of hydrology. In addition, the various options for evaluating the groundwater travel time are put together into a tree diagram. The highest level of the tree diagram is defined by the evaluation factor (groundwater travel time), and evaluation methods are systematically classified into multi-levels that comprise analytical methods/models in one dimension and three dimensions, parameters, datasets, data and investigation methods. Multiple options, such as alternative cases and/or models caused by uncertainties in data, analytical methods and models, are incorporated at each level of the tree diagrams. The feasibility of the tree diagram was examined by tracing both analytical options. Through this examination, the importance of interaction among the site investigation, SA and Design was also demonstrated.

  17. Characterization of unsaturated zone hydrogeologic units using matrix properties and depositional history in a complex volcanic environment

    USGS Publications Warehouse

    Flint, L.E.; Buesch, D.C.; Flint, A.L.

    2006-01-01

    Characterization of the physical and unsaturated hydrologic properties of subsurface materials is necessary to calculate flow and transport for land use practices and to evaluate subsurface processes such as perched water or lateral diversion of water, which are influenced by features such as faults, fractures, and abrupt changes in lithology. Input for numerical flow models typically includes parameters that describe hydrologic properties and the initial and boundary conditions for all materials in the unsaturated zone, such as bulk density, porosity, and particle density, saturated hydraulic conductivity, moisture-retention characteristics, and field water content. We describe an approach for systematically evaluating the site features that contribute to water flow, using physical and hydraulic data collected at the laboratory scale, to provide a representative set of physical and hydraulic parameters for numerically calculating flow of water through the materials at a site. An example case study from analyses done for the heterogeneous, layered, volcanic rocks at Yucca Mountain is presented, but the general approach for parameterization could be applied at any site where depositional processes follow deterministic patterns. Hydrogeologic units at this site were defined using (i) a database developed from 5320 rock samples collected from the coring of 23 shallow (<100 m) and 10 deep (500-1000 m) boreholes, (ii) lithostratigraphic boundaries and corresponding relations to porosity, (iii) transition zones with pronounced changes in properties over short vertical distances, (iv) characterization of the influence of mineral alteration on hydrologic properties such as permeability and moisture-retention characteristics, and (v) a statistical analysis to evaluate where boundaries should be adjusted to minimize the variance within layers. Model parameters developed in this study, and the relation of flow properties to porosity, can be used to produce detailed and accurate representations of the core-scale hydrologic processes ongoing at Yucca Mountain. ?? Soil Science Society of America.

  18. Application of Response Surface based Calibration and Sensitivity Analysis methods for Regional Hydrogeological Modelling in the Western Canada Sedimentary Basin

    NASA Astrophysics Data System (ADS)

    Singh, A.; Palombi, D.; Huff, G. F.

    2014-12-01

    A regional scale study of groundwater flow dynamics was undertaken in the Western Canada Sedimentary Basin (WCSB), comprising parts of Alberta, Saskatchewan and British Columbia. The objective of the study is to investigate basin-scale hydrogeology in WCSB and to establish boundary conditions for future local-scale groundwater management models. Earlier work in the Alberta basin has acknowledged the fact that in addition to topography controlled conditions, a substantial part of the basin exhibits sub-hydrostatic regimes. The basin-scale model (approx. 420,000 km2) includes Upper Cretaceous aquifers to Recent age sediments which collectively attain maximum thicknesses of >2600 m. Regional aquifer units considered for the numerical model are Quaternary sediments, and the sedimentary rocks of the Paskapoo, Scollard, Horseshoe Canyon formations and the Belly River Group. Regional aquitards delineated include the Battle and Bear Paw formations. The study area is bound to the west by the Brazeau-Waptiti thrust belt and to the south by the Canada-USA international border. The boundary to the north and east is delineated by the maximum extent of the Wapiti and Belly River groups and Judith River Formation. USGS MODFLOW was implemented for numerical simulation. The steady state numerical model was calibrated using a Response Surface based (Radial Basis Functions) optimization method. The calibration targets (~2000) were comprised of drill stem tests for deeper units and static water levels for shallower units. Petrophysical analyses of cores averaged K values from analyses of aquifer test results,and literature values were used to provide initial values and calibration ranges for hydraulic properties. Results indicate predominance of topography driven, local- to intermediate-scale flow systems in all hydrostratigraphic units with recharge of these units occurring in the foothills of the Rocky Mountains. The Battle aquitard, where present, acts to retard regional flow. Sensitivity analysis of the steady-state model calibration was evaluated for hydraulic conductivities and recharge rates.

  19. 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

    SciTech Connect

    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