Sample records for hydrogeology

  1. Hydrogeology

    NSDL National Science Digital Library

    This project contains a variety of resources for faculty members who teach undergraduate hydrogeology. We have provided links to a growing collection of activities and assignments, internet and computer resources, useful articles, presentations from the summer 2005 workshop on teaching hydrogeology, working groups and a discussion forum, and lots of creative ideas for teaching hydrogeology.

  2. 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.

  3. Hydrogeologic Mapping

    NSDL National Science Digital Library

    Tom Brikowski

    In this exercise, students learn how to make a preliminary evaluation of the hydrogeology of a site. Students map the location and elevation of important hydrogeologic features, then produce a hydrogeologic map of the site, including a water profile and estimated flow paths for groundwater. This type of map is crucial for evaluating potential sources of groundwater, as well as potential sources of groundwater contamination.

  4. Environmental Hydrogeology

    NSDL National Science Digital Library

    Greg Wiles

    This is the homepage for a 200-level environmental hydrogeology course at the College of Wooster. The site includes a course syllabus, questions to help students prepare for each day of the course, practice exam questions, links and supplemental notes and materials.

  5. Hydrogeological Environments

    NSDL National Science Digital Library

    Peter Riemersma

    This assignment is designed to expose students in my undergraduate 3 credit non lab elective geohydrology course to a variety of hydrogeological environments and groundwater issues/problems that exist in the United States. Much of the course (field trip and local groundwater contamination case study) highlights and emphasizes understanding of the shallow unconsolidated aquifers in Michigan. Students use as their main source of information the data and illustration rich professional USGS Groundwater Atlases. Using this resource, in this activity students learn about the structure of aquifers in volcanic rock, karst and permafrost regions. They teach their fellow students about groundwater problems that result due due to overpumping, subsidence, sinkholes, saltwater intrusion and coal mining. Key words: hydrogeologic environments, water supply and water quality problems, aquifers

  6. 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)

  7. 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...

  8. Hydrogeology Field Course

    NSDL National Science Digital Library

    Department of Geosciences

    This applied hydrogeology field course taught at Western Michigan University is designed to educate and train students in environmental surface geophysics, well drilling and installation, aquifer testing, groundwater sampling and testing, and remediation. The course also offers OSHA 40 hour hazardous waste operations training. This website provides a course outline, photo galleries, a list of skills that will be acquired by students, and logistical information.

  9. ESCI 339: Field Hydrogeology

    NSDL National Science Digital Library

    Laura Sanders

    This is the course home page for a field hydrogeology course taught by Dr. Laura Sanders at Northeastern Illinois University. The site includes the course syllabus, goals for the course as a whole and for each lecture, and a list of field trips. Field methods include stream discharge measurement, storm water management, measuring groundwater elevations, well installation and use of a geoprobe. Field trips include a wetland, a site with a leaking underground storage tank and a landfill.

  10. 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…

  11. Hydrogeology Research Project

    NSDL National Science Digital Library

    Tara Kulkarni

    This activity is for students to work in teams (2012) or individually (2013) to develop a project (such as a physical or numerical model), survey based research, case study, technical briefs on a remediation technology, etc. of the students' choice, based on their understanding of and interest in the subjects covered in the class. This is used in the GL 199 Hydrogeology course, which is offered through the Department of Geology and Environmental Sciences at Norwich University. This is an experimental course that has not made it to the course catalogue as yet. It is currently offered to students majoring in Geology, with an acknowledgement that a course in hydrogeology is a desirable component of a Geology curriculum. Environmental Science students are encouraged to take it to deepen their understanding of subsurface processes. This course is considered a science elective for Civil and Environmental Engineering majors, and greatly complements the Hydrology, and Soils and Materials classes that are a part of the regular CE&E curriculum. Students from freshmen through seniors across these three majors are accepted into the course. With a cross section of majors and academic years in the class, it was determined that a project that has students thinking about a topic of their choice and developing fundamental research and collaboration skills is critical to meeting common workplace demands.

  12. 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...

  13. 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...

  14. 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...

  15. 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.

  16. ESCI 337: Principles of Hydrogeology

    NSDL National Science Digital Library

    Laura Sanders

    This is the course home page for Dr. Laura Sanders' hydrogeology course at Northeastern Illinois University. This web site includes the course syllabus, goals for the course as a whole and for each lecture, homework assignments, hints for solving quantitative problems, and tips for working in groups.

  17. Using Scant Data in Hydrogeology

    NSDL National Science Digital Library

    Don Siegel

    I presented the short case studies at the Teaching Hydrogeology workshop to illustrate the five fundamental points I emphasize in my basic hydrogeology class. These five points are what consultants tell me my students should know cold; what the difference is between the water table and potentiometric head, that a contaminant plume from an individual source should be narrow, that water table maps should be related to the topography, that major dissolved species are important to know about, and that organic matter conditions a lot of contaminant transport. How to apply this knowledge where there is scant data is the rub, and I draw from my consulting files to illustrate how I, at least, do it.

  18. 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.

  19. Hydrogeology of the Galapagos Islands

    NASA Astrophysics Data System (ADS)

    D'Ozouville, N.; Pryet, A.; Violette, S.; de Marsily, G.; Deffontaines, B.; Auken, E.

    2010-12-01

    Due to the heterogeneity of geological formations, volcanic islands present complex and contrasting hydrogeological settings. A young discipline in the Galapagos, hydrogeology requires an understanding of geology, geomorphology, climate and hydrology. Throughout history, navigators, scientists and inhabitants noted the lack of surface freshwater; and water availability limited settlement of the islands. Today, this limitation is overcome through groundwater exploitation and expensive desalination, fed by economic growth. This shift has freed the field of hydrogeology from the existing premise of water being the principal drive for human development. Within this context, our approach is to lead a pluri-disciplinary research to characterize Galapagos hydrogeology. It involves a long-term commitment with international, national and local partners. Field investigations conducted on the inhabited islands of Santa Cruz, San Cristobal, Isabela and Floreana reveal three types of aquifers. A low-lying basal aquifer outcrops on Santa Cruz and Isabela. Due to the high permeability of fractured shield series forming coastal aprons, intruding sea water mixes with discharging freshwater, and confers a high salt content to groundwater. In order to characterize the hydraulic properties of this aquifer, the propagation of the tidal signal into the basal aquifer has been investigated through piezometric monitoring in three open coastal fractures and the deep well on Santa Cruz. Springs are scarce in the Archipelago, but have been identified historically on Santa Cruz and Floreana, located on the flanks of volcanic cones, and fed by small perched aquifers. On San Cristobal, high-level aquifers feed springs on the southern mountainside that contribute to a network of permanent rivers that reach the sea, a unique feature in the whole archipelago. They are independent from El Junco, a unique summital freshwater, and semi-endoreic lake. Internal resistivity structure of Santa Cruz and San Cristobal was revealed through a helicopter borne TEM geophysical survey using the SkyTEM system. An area of over 350 km2 was covered, with depth of investigation of up to 200 m. It allows visualization of 3-dimensional internal low-resistivity layers on the southern windward mountainsides and salt-water intrusion beneath both islands, which relate to some known hydrological features. However, validation of the resistivity model requires drilling of exploration boreholes. Evaporation, runoff and infiltration estimations were obtained from monitoring rainfall and surface runoff in the highlands of Santa Cruz. As an on-going study, new topics of interest are explored: soil properties and contribution of fog water in the hydrological budget; geomorphological context of groundwater emergence; and stable isotopes and noble gases characterization of water masses. The hydrogeology of the central islands provides a window to understand hydro-geomorphological evolution of the Galapagos Islands; and a link between their biological content and the physical environment.

  20. Arizona Hydrogeology And Water Supply

    NASA Astrophysics Data System (ADS)

    Montgomery, E. L.; Harshbarger, J. W.

    1992-01-01

    Arizona hydrogeology and water supply zones are classified into the Basin and Range Lowlands, the Central Highlands, and Plateau Uplands Hydrogeologic Provinces. Average annual precipitation for the state ranges from about five to more than 25 inches; average annual total is about 80 million acre-feet. More than 95 percent of rain and snowfall is lost to evaporation and transpiration. Evaporation potential ranges from about 48 to 86 inches per year and exceeds precipitation at all locations. Most water use is in the agricultural areas and large cities that lie in the Basin and Range Lowlands Province. Groundwater circulation and storage in the Basin and Range Lowlands Province occur chiefly in the extensive alluvial basins. Total groundwater in storage in the basins is more than 1.2 billion acre-feet. Because water use exceeds the rate of replenishment in these basins, groundwater levels have declined, and streamflow from the province is small. The Central Highlands Province provides large amounts of surface-water runoff to the Gila River system where the water is stored in large reservoirs and is used chiefly for agricultural and municipal purposes in the lowlands. Except for large groundwater supplies in fractured rock aquifers at a few locations, groundwater resources in the highlands are small. The Plateau Uplands Province is characterized by extensive flat-lying sandstone and limestone aquifers and by meager surface-water runoff. About 250,000 acre-feet of groundwater are yielded annually from springs that discharge to the Colorado River in the Grand Canyon and to tributaries of the Gila River system along the Mogollon Rim. Largest groundwater yields to wells and to springs occur from abundantly fractured rocks along large faults. The Colorado River flows westward across the northern part of the state and forms the boundary between Arizona and California. Average annual flow in the Colorado River at Lees Ferry is about 12 million acre-feet. The river flow is regulated by reservoirs capable of storing more than 50 million acre-feet. All but about 2.7 million acre-feet per year of the river flow is used in Arizona and California or is lost to evaporation and transpiration.

  1. The hydrogeology of Kilauea volcano

    SciTech Connect

    Ingebritsen, S.E.; Scholl, M.A. (Geological Survey, Menlo Park, CA (United States))

    1993-08-01

    The hydrogeology of Kilauea volcano and adjacent areas has been studied since the turn of this century. However, most studies to date have focused on the relatively shallow, low-salinity parts of the ground-water system, and the deeper hydrothermal system remains poorly understood. The rift zones of adjacent Mauna Loa volcano bound the regional ground-water flow system that includes Kilauea, and the area bounded by the rift zones of Kilauea and the ocean may comprise a partly isolated subsystem. Rates of ground-water recharge vary greatly over the area, and discharge is difficult to measure, because streams are ephemeral and most ground-water discharges diffusely at or below sea level. Hydrothermal systems exist at depth in Kilauea's east and southwest rift zone, as evidenced by thermal springs at the coast and wells in the lower east-rift zone. Available data suggest that dike-impounded, heated ground water occurs at relatively high elevations in the upper east- and southwest-rift zones of Kilauea, and that permeability at depth in the rift zones. Available data suggest that dike-impounded, heated ground water occurs at relatively high elevations in the upper east- and southwest-rift zones of Kilauea, and that permeability at depth in the rift zones (probably [le]10[sup [minus]15] m[sup 2]) is much lower than that of unaltered basalt flows closer to the surface ([ge]10[sup [minus]10] m[sup 2]). Substantial variations in permeability and the presence of magmatic heat sources influence that structure of the fresh water-salt water interface, so the Ghyben-Herzberg model will often fail to predict its position. Numerical modeling studies have considered only subsets of the hydrothermal system, because no existing computer code solves the coupled fluid-flow, heat- and solute-transport problem over the temperature and salinity range encountered at Kilauea. 73 refs., 7 figs., 2 tabs.

  2. 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.

  3. SRP baseline hydrogeologic investigation: Aquifer characterization

    SciTech Connect

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

    1992-03-31

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

  4. 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.

  5. Topics in Hydrogeology: Mud volcanoes and geysers

    E-print Network

    Manga, Michael

    Topics in Hydrogeology: Mud volcanoes and geysers EPS 200 Organizational meeting and overview #12 fluid injection · waste fluid disposal · carbon sequestration · geothermal energy #12;Geysers From Manga and Brodsky (2006) after Husen et al (2004) #12;Geysers · Permeability control? · Oversaturation control

  6. Home page for Applied Hydrogeology textbook

    NSDL National Science Digital Library

    C.W. Fetter

    This is a supplement to the Fourth Edition of Applied Hydrogeology, by C.W. Fetter. The site contains corrections to the text, a review of basic math useful for hydrogeologists, a brief history of the science of groundwater, and the text of the California water rights ruling for Mono Lake. Answers to the text's odd-numbered questions are also provided.

  7. HYDROGEOLOGY OF KARTCHNER CAVERNS STATE PARK, ARIZONA

    Microsoft Academic Search

    CHARLES G. GRAF

    1999-01-01

    Three distinct hydrogeologic systems occur within Kartchner Caverns State Park, Arizona, each in fault contact with the other two. The southeastern corner and eastern edge of the park is part of the large graben that formed the San Pedro Valley during Miocene Basin and Range faulting. A thick alluvial sequence fills this graben and contains a regional aquifer covering 1000

  8. 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...

  9. Hydrogeology and Flooding on the Web

    NSDL National Science Digital Library

    Pamela Gore

    1997-02-19

    Hydrogeology and Flooding on the Web reviews internet sites which contain information on water resources and flood events. Resource categories are flooding, weather-related sites, and hydrology. Some site addresses and image galleries are hyper-linked, while others must be manually cut and pasted into the resource user's browser location.

  10. Hydrogeologic modeling for permeable reactive barriers

    Microsoft Academic Search

    Neeraj Gupta; Tad C Fox

    1999-01-01

    The permeable reactive barrier technology for in situ treatment of chlorinated solvents and other groundwater contaminants is becoming increasingly popular. Field scale implementation of this and other in situ technologies requires careful design based on the site-specific hydrogeology and contaminant plume characteristics. Groundwater flow modeling is an important tool in understanding the hydraulic behavior of the site and optimizing the

  11. The ancient Chinese notes on hydrogeology

    NASA Astrophysics Data System (ADS)

    Zhou, Yu; Zwahlen, François; Wang, Yanxin

    2011-08-01

    The ancient Chinese notes on hydrogeology are summarized and interpreted, along with records of some related matters, like groundwater exploration and utilization, karst springs, water circulation, water conservation and saline-land transformation, mine drainage, and environmental hydrogeology. The report focuses only on the earliest recorded notes, mostly up until the Han Dynasty (206 BC - AD 25). Besides the references cited, the discussion in this report is based mainly on archaeological material, the preserved written classic literature, and some assumptions and/or conclusions that have been handed down in legends to later ages. Although most material relates to ancient China, the lessons learned may have practical significance worldwide. Compared to other contemporary parts of the world, ancient China, without doubt, took the lead in the field of groundwater hydrology. The great achievements and experience of the Chinese ancestors should provide motivation and inspiration for hydrogeologists to carry out their scientific research and exploration passionately and actively.

  12. Seismic refraction exercise for a hydrogeology course

    NSDL National Science Digital Library

    Devin Castendyk

    After reviewing a power point presentation on the use of seismic refraction methods in hydrogeology, students are given seismic refraction data collected on the campus of the State University of New York, College at Oneonta, and asked to determine the depth to the water table in addition to drawing a stratigraphic column. The project can be conducted during class or as a take home assignment. Has minimal/no quantitative component Uses geophysics to solve problems in other fields

  13. GEO-SCI 587: Introduction to Hydrogeology

    NSDL National Science Digital Library

    David Boutt

    This is the home page of a hydrogeology course taught by Dr. David Boutt at the University of Massachusetts. The website includes the course syllabus, lecture notes, homework assignments and lab activities (including three field labs). The course addresses the hydrologic cycle, Darcy's Law, aquifer parameters, steady and transient flow equations, well hydraulics, elementary multi-phase flow, groundwater recharge, watershed hydrology, geological controls on groundwater flow, well construction, and groundwater chemistry and pollution.

  14. Hydrogeology of the West Siberian Basin

    SciTech Connect

    Foley, M.G.; Bradley, D.J.; Cole, C.R. [Pacific Northwest National Lab., Richland, WA (United States)] [and others

    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.

  15. Hydrogeology at the University of Calgary

    NSDL National Science Digital Library

    This University of Calgary website provides summaries of the educational opportunities and of the diverse research interests of the hydrogeology group. Individuals can find synopses of the group's applied isotope geochemistry, electrical resistivity imaging, groundwater modeling, surface-ground water interaction, and hydrology research. The website offers information on the research interests, educational background, and publications of the many faculty, post doctorate, and graduate students. Geologists can find out about graduate assistantships and other research opportunities.

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

    SciTech Connect

    Link, P.K. [ed.

    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. Is current hydrogeologic research addressing long-term predictions?

    PubMed

    Tsang, Chin-Fu

    2005-01-01

    Hydrogeology is a field closely related to the needs of society. Many problems of current national and local interest require predictions of hydrogeological system behavior, and in a number of important cases, the period of prediction is tens to hundreds of thousands of years. It is argued that the demand for such long-term hydrogeological predictions casts a new light on the future needs of hydrogeological research. Key scientific issues are no longer concerned only with simple processes or narrowly focused modeling or testing methods but also with assessment of prediction uncertainties and confidence, couplings among multiple physicochemical processes occurring simultaneously at a site, and the interplay between site characterization and predictive modeling. These considerations also have significant implications for hydrogeological education. With this view, it is asserted that hydrogeological directions and education need to be reexamined and possibly refocused to address specific needs for long-term predictions. PMID:15882321

  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. Hydrogeological aspects of agricultural drainage in Ireland

    NASA Astrophysics Data System (ADS)

    Burdon, David J.

    1986-02-01

    Hydrogeological principles and approaches have been applied to the problems of agricultural drainage in Ireland in the hope that such application will contribute to the better solution of the many drainage problems in Ireland. The legal position and a short history of drainage in Ireland are given, as well as a list of the many state bodies involved in arterial and agricultural drainage. The evolution of the present Irish environment is outlined, from the end of the last ice age to the present day, with emphasis on the formation of lands in need of drainage. Natural conditions indicate that agricultural drainage was required over some 50% (34,450 km2) of Ireland; the achieved agricultural drainage extends over some 29.3% of the country. Natural conditions affecting drainage are set out under the headings of topographical, geological, hydrogeological, vegetative, and hydrochemical influences as well as man's actions with regard to drainage. The third portion of the article deals with the ways in which areas now requiring agricultural drainage have been formed. Areas of low or nil infiltration are described, with some emphasis on such occurrences as lacustrine marls, pans of various types, the effects of the Calp and the Namurian in Carboniferous strate, and conditions under which rejected recharge by overfull aquifers produces winter marshes. Then areas afflicted by high, but often diffuse, groundwater discharge are noted. And the effect of bog growth, both raised bogs and blanket bog, are outlined; drainage of bogs is a very specialized operation, mainly undertaken by Bord na Mona. Some of the harmful affects of drainage are outlined, as reduction of grazing during rare droughts, of lands suitable for waterfowl, as well as some pollution from bog drainage. Drainage does not deplete the groundwater resources of Ireland, which are abundant and little used. The article ends with some general conclusions and a list of some 13 unusual ideas which arise from the application of hydrogeological principles and approaches to problems of agricultural drainage in Ireland.

  20. Hydrogeology of the Islamic Republic of Mauritania

    USGS Publications Warehouse

    Friedel, Michael J.; Finn, Carol

    2008-01-01

    Hydrogeologic maps were constructed for the Islamic Republic of Mauritania. The ground-water flow system in the country can best be described as two interconnected regional systems: the porous Continental Terminal coastal system and the interior, fractured sedimentary Taoudeni Basin system. In these systems, ground-water flow occurs in fill deposits and carbonate, clastic, metasedimentary, and metavolcanic rocks. Based on an evaluation of the potentiometric surface, there are three areas of ground-water recharge in the Taoudeni Basin system. One region occurs in the northwest at the edge of the Shield, one occurs to the south overlying the Tillites, and one is centered at the city of Tidjikdja. In contrast to the flow system in the Taoudeni Basin, the potentiometric surfaces reveal two areas of discharge in the Continental Terminal system but no localized recharge areas; the recharge is more likely to be areal. In addition to these recharge and discharge areas, ground water flows across the country's borders. Specifically, ground water from the Atlantic Ocean flows into Mauritania, transporting dissolved sodium from the west as a salt water intrusion, whereas fresh ground water discharges from the east into Mali. To the north, there is a relatively low gradient with inflow of fresh water to Mauritania, whereas ground-water flow discharges to the Senegal River to the south. A geographical information system (GIS) was used to digitize, manage, store, and analyze geologic data used to develop the hydrogeologic map. The data acquired for map development included existing digital GIS files, published maps, tabulated data in reports and public-access files, and the SIPPE2 Access database. Once in digital formats, regional geologic and hydrologic features were converted to a common coordinate system and combined into one map. The 42 regional geologic map units were then reclassified into 13 hydrogeologic units, each having considerable lateral extent and distinct hydrologic properties. Because the hydrologic properties of these units are also influenced by depth and degree of fracturing, the hydraulic conductivity values of these hydrogeologic units can range over many orders of magnitude.

  1. Surface and subsurface mapping in hydrogeology

    SciTech Connect

    Erdelyi, M.; Galfi, J.

    1987-01-01

    This book concentrates on the often neglected but useful aspects of hydrogeological mapping. It covers geophysical survey methods and the importance of water chemistry as a tool in tracing the route of subsurface water, and goes on to lay a basic foundation in subjects needed for practice in field: stratigraphy, structural geology, mineralogy, petrography, and geochemistry. Also covers basic disciplines and techniques indispensable for geological mapping, e.g., cartography and surveying, geophysics, drilling, soil science, hydrology, and botanics. Written from a uniquely practical standpoint.

  2. University of Tennessee: Hydrogeology Research Program

    NSDL National Science Digital Library

    The hydrogeology research program at the University of Tennessee developed this website to promote its investigation related primarily to groundwater flow and contaminant transport. After reading an overview of the program and its facilities, visitors can discover the endeavors and successes of the numerous researchers. Users can find information and publications discussing the three featured research projects: Chattanooga Creek, Pathogen Transport, and Saprolite Pore Structure; as well as materials on other recent projects. Students can discover the program's three excellent field teaching sites and research opportunities.

  3. SRS baseline hydrogeologic investigation: Summary report

    SciTech Connect

    Bledsoe, H.W.; Aadland, R.K. [Westinghouse Savannah River Co., Aiken, SC (United States); Sargent, K.A. [Furman Univ., Greenville, SC (United States). Dept. of Geology

    1990-11-01

    Work on the Savannah River Site (SRS) Baseline Hydrogeologic Investigation began in 1983 when it was determined that the knowledge of the plant hydrogeologic systems needed to be expanded and improved in response to changing stratigraphic and hydrostratigraphic terminology and increased involvement by regulatory agencies (Bledsoe, 1984). Additionally, site-wide data were needed to determine flow paths, gradients, and velocities associated with the different aquifers underlying the plant site. The program was divided into three phases in order to allow the results of one phase to be evaluated and necessary changes and improvements incorporated into the following phases. This report summarizes the results of all three phases and includes modified graphic logs, lithologic descriptions of the different geologic formations, profiles of each cluster site, hydrostratigraphic cross sections, hydrographs of selected wells within each cluster for the first full year of uninterrupted water level measurements, potentiometric maps developed from data collected from all clusters, completion diagrams for each well, and a summary of laboratory tests. Additionally, the proposed new classification of hydrostratigraphic units at SRS (Aadland and Bledsoe, 1990) has been incorporated.

  4. 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.

  5. 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

  6. Hydrogeology Laboratory Semester Project: Hydrogeologic Assessment for CenTex Water Supply, Inc.

    NSDL National Science Digital Library

    Matthew Uliana

    This activity is a single, semester-long project that involves a hydrogeologic assessment of a property in Central Texas. The project is presented in the lab portion of a hydrogeology class, and it is broken into several separate steps. Each step is treated as a separate assignment, however, the data and results associated with each assignment are applied towards the overall goal of the project. Students are required to maintain a file and a master Excel workbook containing all information, data, and results from each of the steps. All this information is then used to develop an analytical model that simulated drawdowns in the aquifer. This model is used to answer the primary question associated with the project. The results are then documented in a technical report.

  7. 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.

  8. Insights into Mejerda basin hydrogeology, Tunisia

    NASA Astrophysics Data System (ADS)

    Guellala, Rihab; Tagorti, Mohamed Ali; Inoubli, Mohamed Hédi; Amri, Faouzi

    2012-09-01

    The present study concentrates on the interpretation of Vertical Electrical Soundings (VES) and well logs to understand the geometry and the functioning of the Ghardimaou multilayered aquifer, a potential target for water supply in the Mejerda basin (Tunisia). The analysis of isobath and isopach maps established in this study, shows a tectonic influence on the reservoirs structure; the Villafranchian folding and the NE-SW, and E-W normal faulting in the recent Quaternary created an aquifer system compartmentalized by raised and tilted blocks. Geoelectrical cross sections reveal that this structure influences the thickness of permeable formations and the groundwater circulation. These results will be useful for rationalizing the future hydrogeological research that will be undertaken in the Mejerda basin.

  9. 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. [Los Alamos Technical Associates, Albuquerque, NM (United States); Robey, T.H. [Spectra Research Institute, Albuquerque, NM (United States); Rautman, C.A.; Barnard, R.W. [Sandia National Labs., Albuquerque, NM (United States)

    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.

  10. Hydrogeological characterization of peculiar Apenninic springs

    NASA Astrophysics Data System (ADS)

    Cervi, F.; Marcaccio, M.; Petronici, F.; Borgatti, L.

    2014-09-01

    In the northern Apennines of Italy, springs are quite widespread over the slopes. Due to the outcropping of low-permeability geologic units, they are generally characterized by low-yield capacities and high discharge variability during the hydrologic year. In addition, low-flow periods (discharge lower than 1 Ls-1) reflect rainfall and snowmelt distribution and generally occur in summer seasons. These features strongly condition the management for water-supply purposes, making it particularly complex. The "Mulino delle Vene" springs (420 m a.s.l., Reggio Emilia Province, Italy) are one of the largest in the Apennines for mean annual discharge and dynamic storage and are considered as the main water resource in the area. They flow out from several joints and fractures at the bottom of an arenite rock mass outcrop in the vicinity of the Tresinaro River. To date, these springs have not yet been exploited, as the knowledge about the hydrogeological characteristics of the aquifer and their hydrological behaviour is not fully achieved. This study aims to describe the recharge processes and to define the hydrogeological boundaries of the aquifer. It is based on river and spring discharge monitoring and groundwater balance assessment carried out during the period 2012-2013. Results confirm the effectiveness of the approach, as it allowed the total aliquot of discharge of the springs to be assessed. Moreover, by comparing the observed discharge volume with the one calculated with the groundwater balance, the aquifer has been identified with the arenite slab (mean altitude of 580 m a.s.l.), extended about 5.5 km2 and located 1 km west of the monitored springs.

  11. 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...

  12. The application of ecohydrological groundwater indicators to hydrogeological conceptual models.

    PubMed

    Lewis, Jeff

    2012-01-01

    This article reviews the application of ecohydrological indicators to hydrogeological conceptual models for earth-scientists with little or no botanical training. Ecohydrological indicators are plants whose presence or morphology can provide data about the hydrogeological setting. By examining the literature from the fields of ecohydrology, hydrogeology, geobotany, and ecology, this article summarizes what is known about groundwater indicator plants, their potential for providing information about the aquifer, and how this data can be a cost-effective addition to hydrogeological conceptual models. We conclude that the distribution and morphology of ecohydrological groundwater indicator plants can be useful to hydrogeologists in certain circumstances. They are easiest to evaluate in arid and semiarid climates. Ecohydrological groundwater indicators can provide information about the absolute depth to the water table, patterns of groundwater fluctuation, and the mineralization of the aquifer. It is shown that an understanding of the meteorological conditions of a region is often necessary to accurately interpret groundwater indicator plants and that useful data is usually obtained by observing patterns of vegetation behavior rather than interpreting individual plants. The most serious limitations to applying this source of information to hydrogeological conceptual models are the limited data in the literature and the regional nature of many indicator plants. The physical and physiological indications of the plants exist, but little effort has been made to interpret them. This article concludes by outlining several potential lines of research that could further the usefulness of ecohydrological groundwater indicators to the hydrogeological community. PMID:22150517

  13. 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.

  14. 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.

  15. 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.

  16. Hydrogeologic investigations at the Nevada Test Site

    SciTech Connect

    Hawkins, W L [Los Alamos National Lab., NM (United States)] [Los Alamos National Lab., NM (United States); Trudeau, D A [Geological Survey, Las Vegas, NV (United States)] [Geological Survey, Las Vegas, NV (United States); Drellack, S L [Raytheon Services Nevada, Inc., Mercury, NV (United States)] [Raytheon Services Nevada, Inc., Mercury, NV (United States)

    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.

  17. Geophysics and hydrogeology: will they ever marry?.

    NASA Astrophysics Data System (ADS)

    Carrera Ramirez, J.; Martinez-Landa, L.; Perez-Estaun, A.; Vazquez-Sune, E.

    2012-12-01

    The use of geophysics in hydrogeology has long been subject to debate. Geophysicists contend that much information about hydraulic parameters can be obtained from geophysical data, a view shared by some hydrogeologists. On the other hand, many hydrogeologists discuss in private their frustration at failures. The fact that only successes find their way into the published literature justifies the latter in their scepticism. Here, we outline four experiences. In the first case, electrical vertical soundings failed to identify paleochannels at a 10-20 m deep fluvial aquifer overlying marls. In the second case, ERT produced a critically erroneous orientation of terrace deposits less than 10 m deep. In the third case, seismics yielded the location and orientation of singular water conducting faults, which allowed successful non-trivial predictions of the response to long term pumping in a granite pluton. Seismics were also used successfully in the fourth case to identify the location of water conducting faults during the construction of the Barcelona subway. We contend that the difference in these cases does not lie as much in the use of seismic or electrical methods as in the reliance on geology. Whereas geophysical interpretation did not benefit from sedimentologists in the first two cases, structural geologists heavily conditioned the last two through criticism (and rejection) of early interpretations. This, together with the extensive and successful use of electrical methods in regions where geology is well known, suggests that a solid geological model should be a prerequisite for geophysical applications.

  18. Coupled Hydrogeophysical Inversion and Hydrogeological Data Fusion

    NASA Astrophysics Data System (ADS)

    Cirpka, O. A.; Schwede, R. L.; Li, W.

    2012-12-01

    Tomographic geophysical monitoring methods give the opportunity to observe hydrogeological tests at higher spatial resolution than is possible with classical hydraulic monitoring tools. This has been demonstrated in a substantial number of studies in which electrical resistivity tomography (ERT) has been used to monitor salt-tracer experiments. It is now accepted that inversion of such data sets requires a fully coupled framework, explicitly accounting for the hydraulic processes (groundwater flow and solute transport), the relationship between solute and geophysical properties (petrophysical relationship such as Archie's law), and the governing equations of the geophysical surveying techniques (e.g., the Poisson equation) as consistent coupled system. These data sets can be amended with data from other - more direct - hydrogeological tests to infer the distribution of hydraulic aquifer parameters. In the inversion framework, meaningful condensation of data does not only contribute to inversion efficiency but also increases the stability of the inversion. In particular, transient concentration data themselves only weakly depend on hydraulic conductivity, and model improvement using gradient-based methods is only possible when a substantial agreement between measurements and model output already exists. The latter also holds when concentrations are monitored by ERT. Tracer arrival times, by contrast, show high sensitivity and a more monotonic dependence on hydraulic conductivity than concentrations themselves. Thus, even without using temporal-moment generating equations, inverting travel times rather than concentrations or related geoelectrical signals themselves is advantageous. We have applied this approach to concentrations measured directly or via ERT, and to heat-tracer data. We present a consistent inversion framework including temporal moments of concentrations, geoelectrical signals obtained during salt-tracer tests, drawdown data from hydraulic tomography and flowmeter measurements to identify mainly the hydraulic-conductivity distribution. By stating the inversion as geostatistical conditioning problem, we obtain parameter sets together with their correlated uncertainty. While we have applied the quasi-linear geostatistical approach as inverse kernel, other methods - such as ensemble Kalman methods - may suit the same purpose, particularly when many data points are to be included. In order to identify 3-D fields, discretized by about 50 million grid points, we use the high-performance-computing framework DUNE to solve the involved partial differential equations on midrange computer cluster. We have quantified the worth of different data types in these inference problems. In practical applications, the constitutive relationships between geophysical, thermal, and hydraulic properties can pose a problem, requiring additional inversion. However, not well constrained transient boundary conditions may put inversion efforts on larger (e.g. regional) scales even more into question. We envision that future hydrogeophysical inversion efforts will target boundary conditions, such as groundwater recharge rates, in conjunction with - or instead of - aquifer parameters. By this, the distinction between data assimilation and parameter estimation will gradually vanish.

  19. Airborne EM for geothermal and hydrogeological mapping

    NASA Astrophysics Data System (ADS)

    Menghini, A.; Manzella, A.; Viezzoli, A.; Montanari, D.; Maggi, S.

    2012-12-01

    Within the "VIGOR" project, aimed at assessing the geothermal potential of four regions in southern Italy, Airborne EM data have been acquired, modeled and interpreted. The system deployed was SkyTEM, a time-domain helicopter electromagnetic system designed for hydrogeophysical, environmental and mineral investigations. The AEM data provide, after data acquisition, analysis, processing, and modeling, a distribution volume of electrical resistivity, spanning an investigation depth from ground surface of few hundred meters, depending on resistivity condition. Resistivity is an important physical parameter for geothermal investigation, since it proved to be very effective in mapping anomalies due to hydrothermal fluid circulation, which usually has high salt content and produces clayey alteration minerals. Since the project required, among other issues, to define geothermal resources at shallow level, it was decided to perform a test with an airborne electromagnetic geophysical survey, to verify the advantages offered by the system in covering large areas in a short time. The geophysical survey was carried out in Sicily, Italy, in late 2011, over two test sites named "Termini" and "Western Sicily". The two areas were chosen on different basis. "Termini" area is covered by extensive geological surveys, and was going to be investigated also by means of electrical tomography in its northern part. Since geological condition of Sicily, even at shallow depth, is very complex, this area provided a good place for defining the resistivity values of the main geological units outcropping in the region. "Termini" survey has been also an occasion to define relations between resistivity distribution, lithological units and thermal conductivity. The "Western Sicily" area cover the main thermal manifestations of western Sicily, and the research target was to establish whether they are characterized by common hydrogeological or tectonic features that could be mapped by resistivity. SkyTEM data have been acquired in a series of flight lines and were then processed and inverted. In the "Termini" area the flight line spacing had 150 m separation. In the "Western Sicily" area two different line spacing were used: the 1 km spacing was used for the regional mapping, whereas for infill areas, around the main hydrothermal springs, the flight lines had 100 m spacing. The total number of flight line was 4580 km, and the explored surface was in excess of 2000 km2. After acquisition, data were processed to eliminate coupling with infrastructures, and noise. Inversions was then carried out using the quasi 3-D Spatially Constrained Inversion. The obtained resistivity volume has then been the base for a detailed lithological and geothermal interpretation. Lithological and geological maps were used to constrain surface condition and to understand the resistivity ranges of the different lithological units. On the base of resistivity values, lithological units were combined to establish the main litho-resistive units, then modeled at depth, down to achievable investigation depth. This detailed interpretative modeling was also the occasion of recognizing resistivity anomalies within carbonate units, which may possibly represent hydrogeological or hydrothermal bodies. The litho-resitive 3D model is now under investigation to verify how it can represent a viable way to image thermal conductivity variations at depth.

  20. DRASTIC: A STANDARDIZED SYSTEM FOR EVALUATING GROUND WATER POLLUTION POTENTIAL 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 superposition...

  1. 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...

  2. Hydrogeology of Cibola County, New Mexico

    USGS Publications Warehouse

    Baldwin, J.A.; Rankin, D.R.

    1995-01-01

    The hydrogeology of Cibola County, New Mexico, was evaluated to determine the occurrence, availability, and quality of ground-water resources. Rocks of Precambrian through Quaternary age are present in Cibola County. Most rocks are sedimentary in origin except for Precambrian igneous and metamorphic rocks exposed in the Zuni Uplift and Tertiary and Quaternary basalts in northern and central parts of the county. The most productive aquifers in the county include (youngest to oldest) Quaternary deposits, sandstones in the Mesaverde Group, the Dakota-Zuni-Bluff aquifer, the Westwater Canyon aquifer, the Todilto- Entrada aquifer, sandstone beds in the Chinle Formation, and the San Andres-Glorieta aquifer. Unconsolidated sand, silt, and gravel form a mantle ranging from a few inches to 150 to 200 feet over much of the bedrock in Cibola County. Well yields range from 5 to 1,110 gallons per minute. Dissolved-solids concentrations of ground water range from 200 to more than 5,200 milligrams per liter. Calcium, magnesium, bicarbonate, and sulfate are the predominant ions in ground water in alluvial material. The Mesaverde Group mainly occurs in three areas of the county. Well yields range from less than 1 to 12 gallons per minute. The predominant ions in water from wells in the Mesaverde Group are calcium, sodium, and bicarbonate. The transition from calcium-predominant to sodium-predominant water in the southwestern part of the county likely is a result of ion exchange. Wells completed in the Dakota-Zuni-Bluff aquifer yield from 1 to 30 gallons per minute. Dissolved-solids concentrations range from 220 to 2,000 milligrams per liter in water from 34 wells in the western part of the county. Predominant ions in the ground water include calcium, sodium, sulfate, and bicarbonate. Calcium predominates in areas where the aquifer is exposed at the surface or is overlain with alluvium. Sandstones in the Chinle Formation yield from 10 to 300 gallons per minute to wells in the Grants-Bluewater area. In the western part of the county, sodium and bicarbonate predominate in water from the Chinle Formation. In the eastern part of the county, water quality is more variable than elsewhere and the predominant constituents include calcium, sodium, sulfate, and chloride. Well yields from the San Andres-Glorieta aquifer in the Grants- Bluewater area are as much as 2,830 gallons per minute, whereas the maximum recorded pumping rate from the aquifer in other areas of the county is 88 gallons per minute. Dissolved-solids concentrations of ground-water range from about 130 to 4,200 milligrams per liter, and the water generally is a calcium bicarbonate sulfate type.

  3. Hydrogeology of the Azores volcanic archipelago (Portugal)

    NASA Astrophysics Data System (ADS)

    Cruz, J.; Coutinho, R.; Antunes, P.; Freire, P.

    2009-04-01

    The archipelago of the Azores is made of nine islands of volcanic origin located in the North Atlantic Ocean, with an area of 2333 km2 and approximately 237500 inhabitants, which are 98% dependant from groundwater sources for their water consumption. Therefore, groundwater is a resource that plays a vital role as drinking water source and as ecosystem support matrix. Nevertheless, besides the environmental, social and economical value of groundwater, this resource is subject to an increase pressure and in several islands water quality deterioration is shown by monitoring data. This pressure is also shown by the 42.7% increase expected for domestic use until the year 2020 at the Azores, with higher groundwater abstraction. The Azores climate can be considered as marine temperate, which is reflected by the low thermal amplitude and high precipitation. A well-established difference between a dry season and a colder and wet season occurs, as from October to March about 75% of the annual precipitation is registered. The average annual precipitation at the Azores is 1930 mm, exceeding by far the average annual actual evapotranspiration, which is 581 mm. Recharge rates range from 8.5% to 62.1%, and the highest values are observed at Pico, Terceira, Faial, São Miguel and Graciosa islands, especially in areas where the terrain is covered by recent basaltic lava flows and the soil cover is sparse. Groundwater resources estimates point to a total volume of about 1600x106 m3/yr. Values above the recharge median, equal to 101.3x106 m3/yr. were estimated for the São Miguel, São Jorge, Terceira and Flores islands. Despite differences in the islands growth, as a result of successive volcanic eruptions of various types, groundwater occurrence can be described in function of two main aquifers systems: (1) the basal aquifer system, which corresponds to fresh-water lenses floating on underlying salt water, and (2) perched-water bodies, which are usually drained by springs spread in the volcanic edifices slopes. The basal aquifer system is in the coastal area, presenting generally a very low hydraulic gradient. Hydrogeological surveys that have been made in the Azores archipelago points out to more than 1000 springs and wells spread all over the archipelago (950 springs and 83 drilled wells). Spring distribution is heterogeneous, with densities varying between 0.01 springs/km2 at Pico island and 0.72 springs/km2 estimated at Santa Maria. Specific capacity ranges from 1.4x10-2 to 266.7 L/sm, with a median value of 32.3 L/sm. Transmissivity also present a large range, with values ranging between 1.65x10-5 and 4.03x10-1 m2/s, and a median of 3.66x10-2 m2/s. The heterogeneous distribution shown by these values expresses the influence of the hydrogeological characteristics of volcanic terrain, resulting from syngenetic characteristics and secondary processes, like weathering. The highest values are observed in wells drilled in recent basaltic lava flows, which generally are thin and fractured, with frequent clincker levels interbedded, and the lowest data was estimated in the older volcanic formations of Santa Maria island. Groundwater on perched-water bodies, excluding the numerous mineral waters that are spread in several islands of the archipelago, present usually a low mineralization, shown by the electrical conductivity values (36-725 S/cm; median=158.0 S/cm). The average temperature is equal to 15°C. Waters have an average temperature of 15°C and are mainly slightly acid to slightly alkaline, with a pH range from 4.7 to 8.6, but showing a median value of 7.2. The main water types are Na-Cl to Na-HCO3 waters, with numerous samples lying in the intermediate compositional fields that characterize Na-Cl-HCO3 and Na-HCO3-Cl waters. The groundwater composition in the basal aquifer system is usually from the Na-Cl type and presents a higher mineralization, resulting in a median value for electrical conductivity equal to 1044 S/cm, expressing the influence of sea salts mixture.

  4. Low Flow Estimation and Hydrogeology in a Chalk Catchment

    Microsoft Academic Search

    B. Clausen; K. Remer Rasmussen

    1993-01-01

    Procedures to estimate low flow statistics at ungauged sites and their relation to hydrogeology are presented. The discussion is based on an example of a Danish chalk catchment of 242 kmz, within which the climatic variation is small com- pared to the physiographical variation. The spatial and temporal variation of streaniflow was studied using synchronous discharge measurements and the application

  5. Groundwater availability as constrained by hydrogeology and environmental flows.

    PubMed

    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. PMID:23582026

  6. 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

  7. Hydrogeological deformation from GPS time series in Northern Morocco.

    NASA Astrophysics Data System (ADS)

    Moreau, F.; Dauteuil, O.

    2012-04-01

    Actual ground surface deformation can result from many processes, such as tectonics, different kinds of loading like tides, atmospheric or hydrology, etc… Each of these processes is characterized by rather horizontal or vertical displacements, by specific amplitudes and by spatial and time variations. GPS time series measurements are able to register a local displacement containing all this information. The choice of the GPS data acquisition protocol and of the processing strategy is then fundamental for extracting one particular process with sufficient accuracy. In this study, a network of three GPS receivers have been installed since 2008 in the plain of Fez-Meknes in Northern Morocco, with the main objective to extract the hydrogeological information from the approximately two years of displacement data available. Indeed, this agricultural and touristic region is supplied with water from a deep confined aquifer that is overexploited in a context of recurrent droughts. GPS survey is a complementary tool to the hydrogeological measurements to monitor ground water. In terms of other deformation processes, this region can be considered tectonically stable with respect to low seismicity. The Atlantic and Mediterranean coast of Morocco induced a significant Ocean Tide Loading within the continent. A differential processing setup with short baselines of few kilometers long is able to filter this OTL signal and atmospheric loading if any. In regards of the seasonal hydrogeological signal, daily solutions are preferred to smallest sampling in order to optimize the accuracy. Signal processing analysis of the three components of the GPS time series has been performed to identify characteristic frequencies that can be associated with hydrogeological processes. The 3D differential displacements of maximum 2cm between the three GPS receivers can be interpreted by the direction of water flow and by the fractioned structure of the deep aquifer. Finally, this kind of survey can isolate local process such as hydrogeology in the displacement GPS signal.

  8. Development of China Hydrogeology Exploring Techniques in 30 Years --Comparison of Handbook of Hydrogeology of 1st and 2nd Edition

    NASA Astrophysics Data System (ADS)

    Tong, Y.

    2013-12-01

    Handbook of Hydrogeology (2nd edition) is supported by one program from China Geological Survey (CGS): Research of Technical Methods of Hydrogeological Survey and Revision of Handbook of Hydrogeology. It is a reference book for those who are engaged in hydrogeological survey and research in China and covers fundamental principles, theories, survey and exploring techniques, and traditional experiences and achievements in hydrogeology. By comparing the 1st (1978) and 2nd (2012) edition of Handbook of Hydrogeology (in Chinese), this paper analyses the development of China hydrogeological survey and exploring techniques in last 30 years, especially the great change and progress in survey techniques of hydro-remote sensing and hydro-geophysical prospecting. In the first edition of Handbook of Hydrogeology, hydro-remote sensing was only mentioned as an interpretation of aerial pictures in a hydrogeological way, but had not yet formed an independent system and discipline. In the second edition, hydro-remote sensing is an important and independent chapter as one of the hydrogeological techniques. In it, various survey techniques of hydro-remote sensing and types and features of remote sensing data are classified. General systems of interpretation marks of remote sensing images are established, including marks of landform and Quaternary sediment, bedrock, structure types, water yield property, environmental elements of hydrogeology, aquifer group and so on. Systematic workflow is constructed, esp. in remote sensing images mapping and interpreting techniques. GPS and GIS are integrated into remote sensing. Remote sensing exploring instruments and interpreting softwares are also introduced and classified. Although hydro-geophysical prospecting, in the first edition of Handbook of Hydrogeology, was one independent chapter, there were only 10 exploring techniques. Equipments and instruments were simple and lagged in comparison to those in the second edition. The precision and depth were limited. In the last 30 years, geophysical exploring techniques have been widely used in oil and mineral exploration, and have laid a solid foundation for hydro-geophysics. In the second edition, systems of hydro-geophysical techniques are more complete and there are 26 techniques of 2 types. Combination of various geophysical techniques plays a much more effective role in solving hydrogeological problems and makes groundwater exploration more extensively utilized in range, depth and types. After the publication of Handbook of Hydrogeology, it is popular in the field of hydrogeology in China. It is a necessary reference book for hydrogeologists and those in related fields.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

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

    SciTech Connect

    Laky, C.; Lippmann, M.J.; Bodvarsson, G.S. (Lawrence Berkeley Lab., CA (USA)); Retana, M.; Cuellar, G. (Comision Ejecutiva Hidroelectrica del Rio Lempa (CEL) (El Salvador))

    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.

  14. 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.

  15. Impacts of rainfall spatial variability on hydrogeological response

    NASA Astrophysics Data System (ADS)

    Sapriza-Azuri, Gonzalo; Jódar, Jorge; Navarro, Vicente; Slooten, Luit Jan; Carrera, Jesús; Gupta, Hoshin V.

    2015-02-01

    There is currently no general consensus on how the spatial variability of rainfall impacts and propagates through complex hydrogeological systems. Most studies to date have focused on the effects of rainfall spatial variability (RSV) on river discharge, while paying little attention to other important aspects of system response. Here, we study the impacts of RSV on several responses of a hydrological model of an overexploited system. To this end, we drive a spatially distributed hydrogeological model for the semiarid Upper Guadiana basin in central Spain with stochastic daily rainfall fields defined at three different spatial resolutions (fine ? 2.5 km × 2.5 km, medium ? 50 km × 50 km, large ? lumped). This enables us to investigate how (i) RSV at different spatial resolutions, and (ii) rainfall uncertainty, are propagated through the hydrogeological model of the system. Our results demonstrate that RSV has a significant impact on the modeled response of the system, by specifically affecting groundwater recharge and runoff generation, and thereby propagating through to various other related hydrological responses (river discharge, river-aquifer exchange, groundwater levels). These results call into question the validity of management decisions made using hydrological models calibrated or forced with spatially lumped rainfall.

  16. 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.

  17. 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.

  18. Aquifer Hydraulics: A Comprehensive Guide to Hydrogeologic Data Analysis

    NASA Astrophysics Data System (ADS)

    McPherson, Brian J. O. L.

    The past several decades have produced a surge in numerical methods of aquifer analysis, including more complex and sophisticated analytical approaches. For example, many consulting firms and universities have released graphic-intensive software packages for aquifer test data analysis, including automated optimization, data filtering, and preprocessing. It is not uncommon to find users of these products who are not versed in basic theory of aquifer hydraulics. Vedat Batu's Aquifer Hydraulics: A Comprehensive Guide to Hydrogeologic Data Analysis provides a valuable service—it teaches readers the most fundamental theory with a comprehensive overview of basic methods.

  19. 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.

  20. Flow and transport in unsaturated fractured rock: effects of multiscale heterogeneity of hydrogeologic properties

    Microsoft Academic Search

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

    2003-01-01

    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

  1. 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

  2. Hydrogeology and groundwater ecology: Does each inform the other?

    NASA Astrophysics Data System (ADS)

    Humphreys, W. F.

    2009-02-01

    The known, perceived and potential relationships between hydrogeology and groundwater ecology are explored, along with the spatial and temporal scale of these relations, the limit of knowledge and areas in need of research. Issues concerned with the subterranean part of the water cycle are considered from the perspective of the biology of those invertebrate animals that live, of necessity, in groundwater and the microbiological milieu essential for their survival. Groundwater ecosystems are placed in a hydrogeological context including the groundwater evolution along a flowpath, the significance of the biodiversity and of the ecosystem services potentially provided. This is considered against a background of three major components essential to the functioning of groundwater ecosystems, each of which can be affected by activities over which hydrogeologists often have control, and each, in turn, may have implications for groundwater management; these are, a place to live, oxygen and food (energy). New techniques and increasing awareness amongst hydrogeologists of the diversity and broad distribution of groundwater ecosystems offer new opportunities to develop cross disciplinary work between hydrogeologists and groundwater ecologists, already demonstrated to be a field for collaboration with broad benefits.

  3. 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

  4. 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

  5. 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.

  6. 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.

  7. 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.

  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. 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

  10. Water and Mud: Linking hydrogeology and landscape change

    NSDL National Science Digital Library

    Kyle Nichols

    This exercise demonstrates the role of groundwater in Earth's surface processes and natural hazards through a simple sensitivity analysis using Excel and a case study of a landslide in glacial sediments. In the first part of the exercise, students use a spreadsheet to model the infinite slope equation to determine which variables are sensitive to change. In this part of the exercise students discover the relationship and importance between hydrogeology and Earth's surface processes. In the second part of the exercise students use a case study, of a landslide that occurred in glacial sediments, to calculate the lag time between precipitation events and slope failure. This exercise highlights the relationship between groundwater and natural hazards. Finally, students combine their knowledge of both exercises and use the infinite slope equation to predict the percent of ground saturation for the landslide case study.

  11. 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

  12. Hydrogeology of the unsaturated zone, Yucca Mountain, Nevada

    SciTech Connect

    Montazer, P.; Wilson, W.E.

    1985-12-31

    The unsaturated volcanic tuff beneath Yucca Mountain, Nevada, is being evaluated by the US Department of Energy as a host rock for a potential mined geologic repository for high-level radioactive waste. Assessment of site suitability needs an efficient and focused investigative program. A conceptual hydrogeologic model that simulates the flow of fluids through the unsaturated zone at Yucca Mountain was developed to guide the program and to provide a basis for preliminary assessment of site suitability. The study was made as part of the Nevada Nuclear Waste Storage Investigations Project of the US Department of Energy. Thickness of the unsaturated zone is about 1640 to 2460 feet (500 to 750 meters). Based on physical properties, the rocks in the unsaturated zone are grouped for the purpose of this paper into five informal hydrogeologic units. From top to bottom these units are: Tiva Canyon welded unit, Paintbrush nonwelded unit. Topopah Spring welded unit, Calico Hills nonwelded unit, and Crater Flat unit. Welded units have a mean fracture density of 8 to 40 fractures per unit cubic meter, mean matrix porosities of 12 to 23%, matrix hydraulic conductivities with geometric means ranging from 6.5 x 10{sup -6} to 9.8 x 10{sup -6} foot per day (2 x 10{sup -6} to 3 x 10{sup -6} meter per day), and bulk hydraulic conductivities of 0.33 to 33 feet per day (0.1 to 10 meters per day). The nonwelded units have a mean fracture density of 1 to 3 fractures per unit cubic meter, mean matrix porosities of 31 to 46%, and saturated hydraulic conductivities with geometric means ranging from 2.6 x 10{sup -5} to 2.9 x 10{sup -2} foot per day (8 x 10{sup -6} to 9 x 10{sup -3} meter per day). 15 refs., 4 figs., 1 tab.

  13. Summary of hydrogeologic and ground-water-quality data and hydrogeologic framework at selected well sites, Adams County, Pennsylvania

    USGS Publications Warehouse

    Low, Dennis J.; Dugas, Diana L.

    1999-01-01

    Rapid population growth in Adams County has increased the demand for ground water and led Adams County planning officials to undertake an effort to evaluate the capabilities of existing community water systems to meet future, projected growth and to begin wellhead-protection programs for public-supply wells. As part of this effort, this report summarizes ground-water data on a countywide scale and provides hydrogeologic information needed to delineate wellheadprotection areas in three hydrogeologic units (Gettysburg Lowland, Blue Ridge, and Piedmont Lowland). Reported yields, specific capacities, well depths, and reported overburden thickness can vary by hydrogeologic unit, geologic formation, water use (domestic and nondomestic), and topographic setting. The reported yields of domestic wells drilled in the Gettysburg Lowland (median reported yield of 10 gallons per minute) are significantly greater than the reported yields from the Blue Ridge, Piedmont Lowland, and Piedmont Upland (median reported yields of 7.0, 8.0, and 7.0 gallons per minute, respectively). Reported yields of domestic wells completed in the diabase and the New Oxford Formation of the Gettysburg Lowland, and in the metarhyolite and metabasalt of the Blue Ridge, are significantly lower than reported yields of wells completed in the Gettysburg Formation. For nondomestic wells, reported yields from the Conestoga Formation of the Piedmont Lowland are significantly greater than in the diabase. Reported yields of nondomestic wells drilled in the Gettysburg, New Oxford, and Conestoga Formations, and the metarhyolite are significantly greater than those for domestic wells drilled in the respective geologic formations. Specific capacities of nondomestic wells in the Conestoga and Gettysburg Formations are significantly greater than their domestic counterparts. Specific capacities of nondomestic wells in the Conestoga Formation are significantly greater than the specific capacities of nondomestic wells in the metarhyolite, diabase, and Gettysburg and New Oxford Formations.Well depths do not vary considerably by hydrogeologic unit; instead, the greatest variability is by water use. Nondomestic wells drilled in the metarhyolite, Kinzers, Conestoga, Gettysburg, and New Oxford Formations are completed at significantly greater depths than their domestic counterparts. The reported thickness of overburden varies significantly by geologic formation and water use, but not by topographic setting. The median overburden thickness of the Blue Ridge (35 feet) is greater than in any other hydrologic unit. Except where adversely affected by human activities, ground water in Adams County is suitable for most purposes. Calcium and magnesium are the dominant cations, and bicarbonate is the dominant anion. In general, the pH and hardness of ground water is lower in areas that are underlain by crystalline rocks (Blue Ridge and Piedmont Upland) than in areas underlain by sedimentary rocks, especially where limestone or dolomite is dominant (Piedmont Lowland). Dissolved nitrate (as N) and dissolved nitrite (as N) concentrations in the water from 9 of 69 wells and 3 of 80 wells sampled exceeded the U.S. Environmental Protection Agency (USEPA) maximum contaminant levels (MCL) of 10 and 1.0 mg/L (milligrams per liter), respectively. Sulfate concentrations greater than the proposed USEPA MCL of 500 mg/L were reported from the water in 3 of 110 wells sampled. Iron concentrations in the water from 13 of 67 wells sampled and manganese in the water from 9 of 64 wells sampled exceeded the USEPA secondary maximum contaminant level (SMCL) of 300 and 50 mg/L (micrograms per liter), respectively. Aluminum concentrations in the water from 16 of 22 wells sampled exceeded the lower USEPA SMCL threshold of 50 mg/L. Pesticides were detected in the water from seven wells but at concentrations that did not exceed USEPA MCL?s. Most volatile organic compounds detected in the ground water were confined to USEPA S

  14. 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. [and others

    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.

  15. 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.

  16. 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.

  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. Hydrogeologic Modeling at the Sylvania Corning FUSRAP Site - 13419

    SciTech Connect

    Ewy, Ann [U.S. Army Corps of Engineers, Kansas City District (United States)] [U.S. Army Corps of Engineers, Kansas City District (United States); Heim, Kenneth J. [U.S. Army Corps of Engineers, New England District (United States)] [U.S. Army Corps of Engineers, New England District (United States); McGonigal, Sean T.; Talimcioglu, Nazmi M. [The Louis Berger Group, Inc. (United States)] [The Louis Berger Group, Inc. (United States)

    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

  19. 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.

  20. Feedbacks Between Numerical and Analytical Models in Hydrogeology

    NASA Astrophysics Data System (ADS)

    Zlotnik, V. A.; Cardenas, M. B.; Toundykov, D.; Cohn, S.

    2012-12-01

    Hydrogeology is a relatively young discipline which combines elements of Earth science and engineering. Mature fundamental disciplines (e.g., physics, chemistry, fluid mechanics) have centuries-long history of mathematical modeling even prior to discovery of Darcy's law. Thus, in hydrogeology, relatively few classic analytical models (such those by Theis, Polubarinova-Kochina, Philip, Toth, Henry, Dagan, Neuman) were developed by the early 1970's. The advent of computers and practical demands refocused mathematical models towards numerical techniques. With more diverse but less mathematically-oriented training, most hydrogeologists shifted from analytical methods to use of standardized computational software. Spatial variability in internal properties and external boundary conditions and geometry, and the added complexity of chemical and biological processes will remain major challenges for analytical modeling. Possibly, analytical techniques will play a subordinate role to numerical approaches in many applications. On the other hand, the rise of analytical element modeling of groundwater flow is a strong alternative to numerical models when data demand and computational efficiency is considered. The hallmark of analytical models - transparency and accuracy - will remain indispensable for scientific exploration of complex phenomena and for benchmarking numerical models. Therefore, there will always be feedbacks and complementarities between numerical and analytical techniques, as well as a certain ideological schism among various views to modeling. We illustrate the idea of feedbacks by reviewing evolution of Joszef Toth's analytical model of gravity driven flow systems. Toth's (1963) approach was to reduce the flow domain to a rectangle which allowed for closed-form solution of the governing equations. Succeeding numerical finite-element models by Freeze and Witherspoon (1966-1968) explored the effects of geometry and heterogeneity on regional groundwater flow, but others (e.g., Ophori and Toth, 1990) still maintained the "rectangular" simplification. The interest in this conceptual model was rekindled by Worman et al. (2006, 2007) that used Fourier analyses of analytical solutions for effects of topography in regional flow systems or irregular head distributions in streambeds on hyporheic flow systems. The caveat of analytical techniques for such applications is a problem of "missing domain" resulting from truncation of the flow domain to a rectangle. This issue becomes important in systems where major processes are focused in or near the truncated domain compared to deeper regions. Using perturbation techniques we illustrate a technique for extending analysis of Tothian flow to non-rectangular and non-rectilinear domains; we developed analytical solutions for flow with top boundaries of arbitrary shape. Discussed are possible ramifications for transient models, including well hydraulics.

  1. Hydrogeology of the Potsdam Sandstone in northern New York

    USGS Publications Warehouse

    Williams, John H.; Reynolds, Richard J.; Franzi, David A.; Romanowicz, Edwin A.; Paillet, Frederick L.

    2010-01-01

    The Potsdam Sandstone of Cambrian age forms a transboundary aquifer that extends across northern New York and into southern Quebec. The Potsdam Sandstone is a gently dipping sequence of arkose, subarkose, and orthoquartzite that unconformably overlies Precambrian metamorphic bedrock. The Potsdam irregularly grades upward over a thickness of 450 m from a heterogeneous feldspathic and argillaceous rock to a homogeneous, quartz-rich and matrix-poor rock. The hydrogeological framework of the Potsdam Sandstone was investigated through an analysis of records from 1,500 wells and geophysical logs from 40 wells, and through compilation of GIS coverages of bedrock and surficial geology, examination of bedrock cores, and construction of hydrogeological sections. The upper several metres of the sandstone typically is weathered and fractured and, where saturated, readily transmits groundwater. Bedding-related fractures in the sandstone commonly form sub-horizontal flow zones of relatively high transmissivity. The vertical distribution of sub-horizontal flow zones is variable; spacings of less than 10 m are common. Transmissivity of individual flow zones may be more than 100 m2/d but typically is less than 10 m2/d. High angle fractures, including joints and faults, locally provide vertical hydraulic connection between flow zones. Hydraulic head gradients in the aquifer commonly are downward; a laterally extensive series of sub-horizontal flow zones serve as drains for the groundwater flow system. Vertical hydraulic head differences between shallow and deep flow zones range from 1 m to more than 20 m. The maximum head differences are in recharge areas upgradient from the area where the Chateauguay and Chazy Rivers, and their tributaries, have cut into till and bedrock. Till overlies the sandstone in much of the study area; its thickness is generally greatest in the western part, where it may exceed 50 m. A discontinuous belt of bedrock pavements stripped of glacial drift extends across the eastern part of the study area; the largest of these is Altona Flat Rock. Most recharge to the sandstone aquifer occurs in areas of thin, discontinuous till and exposed bedrock; little recharge occurs in areas where this unit is overlain by thick till and clay. Discharge from the sandstone aquifer provides stream and river baseflow and is the source of many springs. A series of springs that are used for municipal bottled water and fish-hatchery supply discharge from 1,000 to 5,000 L/min adjacent to several tributaries east of the Chateauguay River. The major recharge areas for the Chateauguay springs are probably upgradient to the southeast, where the till cover is thin or absent.

  2. 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.

  3. 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.

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

    SciTech Connect

    Nativ, R. [Hebrew Univ., Jerusalem (IL); Hunley, A.E. [Oak Ridge National Lab., TN (United States)

    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.

  5. Hydrogeology of the Canal Creek area, Aberdeen Proving Ground, Maryland

    USGS Publications Warehouse

    Oliveros, J.P.; Vroblesky, D.A.

    1989-01-01

    Geologic and borehole geophysical logs made at 77 sites show that the hydrogeologic framework of the study area consists of a sequence of unconsolidated sediments typical of the Coastal Plain of Maryland. Three aquifers and two confining units were delineated within the study area. From the surface down, they are: (1) the surficial aquifer; (2) the upper confining unit; (3) the Canal Creek aquifer; (4) the lower confining unit; and (5) the lower confined aquifer. The aquifer materials range from fine sand to coarse sand and gravel. Clay lenses were commonly found interfingered with the sand, isolating parts of the aquifers. All the units are continuous throughout the study area except for the upper confining unit, which crops out within the study area but is absent in updip outcrops. The unit also is absent within a Pleistocene paleochannel, where it has been eroded. The surficial and Canal Creek aquifers are hydraulically connected where the upper confining unit is absent, and a substantial amount of groundwater may flow between the two aquifers. Currently, no pumping stresses are known to affect the aquifers within the study area. Under current conditions, downward vertical hydraulic gradients prevail at topographic highs, and upward gradients typically prevail near surface-water bodies. Regionally, the direction of groundwater flow in the confined aquifers is to the east and southeast. Significant water level fluctuations correspond with seasonal variations in rainfall, and minor daily fluctuations reflect tidal cycles. (USGS)

  6. A methodological approach to identify rainfall causing damaging hydrogeological events

    NASA Astrophysics Data System (ADS)

    Petrucci, Olga; Aceto, Luigi

    2014-05-01

    The paper deals with Damaging Hydrogeological Events (DHEs), defined as periods of severe weather affecting wide regions for several days, and during which landslides and floods cause economic damage and victims. The great variability of DHEs, in both space and time, is the cause of one of main problems to solve in performing the analysis of these events. Dealing with events affecting wide areas for several days, it is challenging to isolate the rainy days that can be considered as triggering factors of the observed damaging phenomena. In this paper we consider 30 catastrophic DHEs which occurred in Calabria (southern Italy) between 1981 and 2010, and we develop a methodological approach aiming to both select and analyze rainfall events that triggered damage. The performed analysis allows highlighting some seasonal characteristics of Calabrian DHEs. More in general, the proposed approach can be used in regions affected by DHEs for which damage and rainfall data are available. Practical results that could be obtained concern: a) individuation of rainfall thresholds for the triggering of DHEs, at both regional and sub-regional scale; b) individuation of relationships between temporal distribution of rain and types of phenomena triggered; c) individuation of rain/damage relationships at sub-regional scale; and d) analysis of the pattern of rainy days which triggered a long historical series of DHEs, in order to highlight if the most recent events affecting the study area were mainly caused by short and intense rain, as it seems the tendency related to the climate change.

  7. Hydrogeology of glacial-terrain lakes, with management and planning applications

    USGS Publications Warehouse

    Born, S.M.; Smith, S.A.; Stephenson, D.A.

    1979-01-01

    The subject of the relationship between groundwater and lakes is characterized by sparse information and, in general, has received limited attention by hydrologists. Nevertheless, the hydrogeologic regime of lakes must be adequately assessed in order to intelligently manage lakes and their related shorelands. This paper is a compilation of hydrogeologic data for numerous lakes in North America and presents a preliminary classification framework for lakes based on hydrogeologic considerations. The classification leads to systematic categorization of lake types for planning and management purposes. The main hydrogeologic factors for assessing lake environments are: (1) regime dominance, the relative magnitude of groundwater in the total water budget of a lake; (2) system efficiency, a description of the rate aspects of surface and groundwater movement through a lake system; and (3) position within a groundwater flow system. We indicate the significance and difficulty of measuring these descriptive characteristics and provide examples of each category. Additionally, a variety of lake-related activities that illustrate the value of hydrogeologic information for planning and management purposes are presented. ?? 1979.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. Hydrogeologic Modeling for Monitoring, Reporting and Verification of Geologic Sequestration

    NASA Astrophysics Data System (ADS)

    Kolian, M.; De Figueiredo, M.; Lisa, B.

    2011-12-01

    In December 2010, EPA finalized Subpart RR of the Greenhouse Gas (GHG) Reporting Program, which requires facilities that conduct geologic sequestration (GS) of carbon dioxide (CO2) to report GHG data to EPA annually. The GHG Reporting Program requires reporting of GHGs and other relevant information from certain source categories in the United States, and information obtained through Subpart RR will inform Agency decisions under the Clean Air Act related to the use of carbon dioxide capture and sequestration for mitigating GHGs. This paper examines hydrogeologic modeling necessities and opportunities in the context of Subpart RR. Under Subpart RR, facilities that conduct GS by injecting CO2 for long-term containment in subsurface geologic formations are required to develop and implement an EPA-approved site-specific monitoring, reporting, and verification (MRV) plan; and report basic information on CO2 received for injection, annual monitoring activities and the amount of CO2 geologically sequestered using a mass balance approach. The major components of the MRV plan include: identification of potential surface leakage pathways for CO2 and the likelihood, magnitude, and timing, of surface leakage of CO2 through these pathways; delineation of the monitoring areas; strategy for detecting and quantifying any surface leakage of CO2; and the strategy for establishing the expected baselines for monitoring CO2 surface leakage. Hydrogeologic modeling is an integral aspect of the design of an MRV plan. In order to prepare an adequate monitoring program that addresses site specific risks over the full life of the project the MRV plan must reflect the full spatial extent of the free phase CO2 over time. Facilities delineate the maximum area that the CO2 plume is predicted to cover and how monitoring can be phased in over this area. The Maximum Monitoring Area (MMA) includes the extent of the free phase CO2 plume over the lifetime of the project plus a buffer zone of one-half mile. The Active Monitoring Area (AMA) is the area that will be monitored over a specified time interval chosen by the reporter, which must be greater than one year. All of the area in the MMA will eventually be covered by one or more AMAs. This allows operators to phase in monitoring so that during any given time interval, only that part of the MMA in which surface leakage might occur needs to be monitored. EPA designed the MRV plan approach to be site-specific, flexible, and adaptive to future technology developments. This approach allows the reporter to leverage the site characterization, modeling, and monitoring approaches (e.g. monitoring of injection pressures, injection well integrity, groundwater quality and geochemistry, and CO2 plume location, etc.) developed for their Underground Injection Control (UIC) permit. UIC requirements provide the foundation for the safe sequestration of CO2 by helping to ensure that injected fluids remain isolated in the subsurface and away from underground sources of drinking water, thereby serving to reduce the risk of CO2 leakage to the atmosphere.

  13. 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.

  14. 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.

  15. 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.

  16. Hydrogeologic Framework of the Yakima River Basin Aquifer System, Washington

    USGS Publications Warehouse

    Vaccaro, J.J.; Jones, M.A.; Ely, D.M.; Keys, M.E.; Olsen, T.D.; Welch, W.B.; Cox, S.E.

    2009-01-01

    The Yakima River basin aquifer system underlies about 6,200 square miles in south-central Washington. The aquifer system consists of basin-fill deposits occurring in six structural-sedimentary basins, the Columbia River Basalt Group (CRBG), and generally older bedrock. The basin-fill deposits were divided into 19 hydrogeologic units, the CRBG was divided into three units separated by two interbed units, and the bedrock was divided into four units (the Paleozoic, the Mesozoic, the Tertiary, and the Quaternary bedrock units). The thickness of the basin-fill units and the depth to the top of each unit and interbed of the CRBG were mapped. Only the surficial extent of the bedrock units was mapped due to insufficient data. Average mapped thickness of the different units ranged from 10 to 600 feet. Lateral hydraulic conductivity (Kh) of the units varies widely indicating the heterogeneity of the aquifer system. Average or effective Kh values of the water-producing zones of the basin-fill units are on the order of 1 to 800 ft/d and are about 1 to 10 ft/d for the CRBG units as a whole. Effective or average Kh values for the different rock types of the Paleozoic, Mesozoic, and Tertiary units appear to be about 0.0001 to 3 ft/d. The more permeable Quaternary bedrock unit may have Kh values that range from 1 to 7,000 ft/d. Vertical hydraulic conductivity (Kv) of the units is largely unknown. Kv values have been estimated to range from about 0.009 to 2 ft/d for the basin-fill units and Kv values for the clay-to-shale parts of the units may be as small as 10-10 to 10-7 ft/d. Reported Kv values for the CRBG units ranged from 4x10-7 to 4 ft/d. Variations in the concentrations of geochemical solutes and the concentrations and ratios of the isotopes of hydrogen, oxygen, and carbon in groundwater provided information on the hydrogeologic framework and groundwater movement. Stable isotope ratios of water (deuterium and oxygen-18) indicated dispersed sources of groundwater recharge to the CRBG and basin-fill units and that the source of surface and groundwater is derived from atmospheric precipitation. The concentrations of dissolved methane were larger than could be attributable to atmospheric sources in more than 80 percent of wells with measured methane concentrations. The concentrations of the stable isotope of carbon-13 of methane were indicative of a thermogenic source of methane. Most of the occurrences of methane were at locations several miles distant from mapped structural fault features, suggesting the upward vertical movement of thermogenic methane from the underlying bedrock may be more widespread than previously assumed or there may be a more general occurrence of unmapped (buried) fault structures. Carbon and tritium isotope data and the concentrations of dissolved constituents indicate a complex groundwater flow system with multiple contributing zones to groundwater wells and relative groundwater residence time on the order of a few tens to many thousands of years. Potential mean annual recharge for water years 1950-2003 was estimated to be about 15.6 in. or 7,149 ft3/s (5.2 million acre-ft) and includes affects of human activities such as irrigation of croplands. If there had been no human activities (predevelopment conditions) during that time period, estimated recharge would have been about 11.9 in. or 5,450 ft3/s (3.9 million acre-ft). Estimated mean annual recharge ranges from virtually zero in the dry parts of the lower basin to more than 100 in. in the humid uplands, where annual precipitation is more than 120 in. Groundwater in the different hydrogeologic units occurs under perched, unconfined, semiconfined, and confined conditions. Groundwater moves from topographic highs in the uplands to topographic low areas along the streams. The flow system in the basin-fill units is compartmentalized due to topography and geologic structure. The flow system also is compartmentalized for the CRBG units but not to as large

  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. HYDROGEOLOGIC MODELLING FOR PERMEABLE REACTIVE BARRIERS DESIGN Manon Kimmel *, Benjamin Piel *, Hafid Baroudi *, Annette Esnault-Filet **, Xavier Laloum **, Dominique

    E-print Network

    Paris-Sud XI, Université de

    HYDROGEOLOGIC MODELLING FOR PERMEABLE REACTIVE BARRIERS DESIGN Manon Kimmel *, Benjamin Piel.Mazzieri(S),soletanche-bachy.com Key words : reactive barriers, groundwater clean-up, in-situ remediation, design method, hydrogeologic modelling Summary Perméable Reactive Barrier is an in-situ reactive System used for passive groundwater

  19. SRP baseline hydrogeologic investigation: Aquifer characterization. Groundwater geochemistry of the Savannah River Site and vicinity

    SciTech Connect

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

    1992-03-31

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  1. 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.

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

    SciTech Connect

    Weaver, B. [American Geophysical Union, Washington, DC (United States)

    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.

  3. Hydrogeologic Controls on Bioactive Zone Development in Biostimulated Aquifers

    NASA Astrophysics Data System (ADS)

    Schillig, Peter Curtis

    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 interaction between groundwater flow and bioactive zone development was investigated in both a subsurface biostimulation study and a laboratory experiments. Prior to the investigation, necessary advances were made in point velocity probe (PVP) technology to ensure successful observation in the field. Advances in these areas allowed for high resolution site characterization of an aquifer to undergo biostimulation for the removal of nitrate contamination. Heterotrophic denitrification was stimulated through daily pulses of acetate into the aquifer. With the onset of acetate delivery, decreases in groundwater velocity magnitude and flow redirection were correlated with permeable zones of relatively finer grain-size and poorer-sorting. In contrast, adjacent well-sorted and relatively coarse zones with initially high groundwater velocities indicated relatively little or no change in groundwater velocity after biostimulation. Superimposed onto these results, greater changes in groundwater velocity were noted where individual acetate pulses mixed through dispersive processes. In contrast, locations up-gradient of acetate pulse mixing indicated a higher variability in measured groundwater velocity. In total, changes in groundwater velocity in the biostimulated zone were in excess of those anticipated by analysis of the hydraulic gradient. Sediment-attached viable cell populations were interpreted to be partially responsible for the measured changes in velocity. Variables of grain-size and initial groundwater velocity were tested in controlled laboratory column experiments to evaluate the most favorable conditions for a bioactive zone to develop, subsequently leading to preferential bioclogging. Results from these experiments supported field observations that transition zones where relatively fine-grained, permeable sediments that lie adjacent to discontinuous coarser sediments---where the high velocities would lead to the highest flux of injected nutrients---represents the likely starting place for bioactive zone development, but may also be at greater risk for bioclogging. Further work was conducted to show that ground penetrating radar could noninvasively detect zones of relatively high bioactivity in granular material.

  4. 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.

  5. 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.

  6. A Task-oriented Approach for Hydrogeological Site Characterization

    NASA Astrophysics Data System (ADS)

    Rubin, Y.; Nowak, W.; de Barros, F.

    2010-12-01

    Hydrogeological site characterization is a challenging task from several reasons: (1) the large spatial variability and scarcity of prior information render the outcome of any planned sampling campaign uncertain; (2) there are no simple tools for comparing between the many alternative measurement techniques and data acquisition strategies, and (3) physical and budgetary constraints associated with data acquisition. This paper presents several ideas on how to plan sampling campaigns in a rational manner while addressing these challenges. The first idea is to recognize that different sites and different problems require different characterization strategies. Hence the idea is to plan data acquisition according to its capability for meeting site-specific goals. For example, the characterization needs at a “research problem” site (e.g., a site intended to investigate the transport of uranium in the subsurface such as in Hanford) are different from those of a “problem” site (e.g., contaminated site associated with a health risk to human such as Camp Lejeune, or determining the safe yield of an aquifer). This distinction requires planners to define the characterization goal(s) in a quantitative manner. The second idea is to define metrics that could link specific data types and data acquisition strategies with the site-specific goals in a way that would allow planners to compare between strongly different, alternatives strategies at the design stage (even prior to data acquisition) and to modify the strategies as more data become available. To meet this goal, we developed the concept of the (comparative) information yield curve. Finally, we propose to look at site characterization from the perspective of statistical hypothesis testing, whereby data acquisition strategies could be evaluated in terms of their ability to support or refute various hypotheses made with regard to the characterization goals, and the strategies could be modified once the test is completed. Accept/reject regions for hypothesis testing can be determined based on goals determined by regulations or by agreement between the stakeholders. Hypothesis-driven design could help in minimizing the chances of making wrong decision (false positives or false negatives) with regard to the site-specific goals.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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...

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

    E-print Network

    Paris-Sud XI, Université de

    of the French West Indies island of Guadeloupe. It has been the subject of a large number of studies covering are part of the French West Indies (Figure 1) that lie on the Lesser Antilles island arc (Andreieff1 Hydrogeological model of a high energy geothermal field (Bouillante area, Guadeloupe, French West

  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. 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...

  15. HBGC123D: a high-performance computer model of coupled hydrogeological and biogeochemical processes

    Microsoft Academic Search

    Jin P. Gwo; Eduardo F D’Azevedo; Hartmut Frenzel; Melanie Mayes; Gour-Tsyh Yeh; Philip M. Jardine; Karen M. Salvagee; Forrest M. Hoffman

    2001-01-01

    Groundwater flow and transport models have been used to assist management of subsurface water resources and water quality. The needs of more efficient use of technical and financial resources have recently motivated the development of more effective remediation techniques and complex models of coupled hydrogeological and biogeochemical processes. We present a high-performance computer model of the coupled processes, HBGC123D. The

  16. The worth of data in predicting aquitard continuity in hydrogeological design

    Microsoft Academic Search

    Bruce R. James; R. Allan Freeze

    1993-01-01

    A Bayesian decision framework is developed for addressing questions of hydrogeological data worth associated with engineering design at sites in heterogeneous geological environments. The specific case investigated is one of remedial contaminant containment in an aquifer underlain by an aquitard of uncertain continuity. The framework is used to evaluate the worth of hard and soft data in investigating the aquitard's

  17. The worth of data in predicting aquitard continuity in hydrogeological design

    Microsoft Academic Search

    Bruce R. James; R. Allan Freeze

    1993-01-01

    A Bayesian decision framework is developed for addressing questions of hydrogeological data worth associated with engineering design at sites in heterogeneous geological environments. The specific case investigated is one of remedial contaminant in an aquifer underlain by an aquitard of uncertain continuity. The framework is used to evaluate the worth of hard and soft data in investigating the aquitard's continuity.

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

    Microsoft Academic Search

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

    2009-01-01

    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

  19. Development of a Hydrogeological Site Description Based on a Discrete Fracture Network Concept and the Integration of Geological, Hydrogeological and Hydrochemical Data

    NASA Astrophysics Data System (ADS)

    Jackson, C.; Hartley, L. J.; Hoch, A.; Holton, D.; Hunter, F. M.; McCarthy, R.; Marsic, N.; Gylling, B.

    2006-12-01

    The Swedish Nuclear Fuel and Waste Management Company (SKB) is carrying out site investigations in two different areas in Sweden with the objective of describing the in-situ conditions for a deep rock repository for spent nuclear fuel. The two candidate areas are Forsmark and Laxemar, both located on the east coast of Sweden. An important aspect of site investigations is to develop and demonstrate an understanding of groundwater flow and solute transport. Since the geology in both candidate areas is comprised of hard crystalline rocks, the groundwater flow is predominantly contained within fractures, and therefore a discrete fracture network (DFN) concept has been applied to describe and model the hydrogeological situation at the sites. Much observed field data from several different disciplines (geology, rock mechanics, geophysics, hydrogeology and hydrochemistry) has been acquired from the sites, including from several deep cored boreholes, to inform an overall description. Many aspects of the site description are brought together in constructing a regional scale hydrogeological model to integrate the concepts and data interpretations, which are then tested against a range of field observations to build confidence that the models are representative. A methodology has been developed based on assembling a regional hydrogeological model from three main components: hydraulic conductor domains (HCD) that represent deterministic large scale deformation zones; hydraulic rock domains (HRD) that use a stochastic DFN model to represent the background rock between the deformation zones; and hydraulic soil domains (HSD) that represent near-surface Quaternary deposits. The HCD are interpreted from geophysical methods, drilling and single-hole hydraulic tests. For the HRD, borehole image- and core-logs, outcrop maps, and short-interval flow-logging are integrated to parameterise a DFN model for specific hydrogeological rock domains. Geological information, statistical analysis and expert judgement are used to extrapolate the DFN model over the regional domain. For regional-scale flow simulations, 3D stochastic realisations of the DFN model are converted, using flux-based upscaling techniques, to an equivalent continuum porous medium (ECPM) model that includes density driven flow and rock matrix diffusion. Testing of the model parameterisation is achieved by simulating hydraulic interference tests and transport of natural chemical tracers. The tracers include major elemental ions, stable isotopes and tritium measured in groundwater samples from boreholes. The hydrochemistry of these coastal sites has been strongly affected by palaeo-hydrogeolgical processes resulting from glacial melting, land-rise and marine transgressions following the last ice age. Therefore, 3D transient coupled groundwater flow and solute transport simulations are used to model these processes with the purpose of calibrating and testing the hydrogeological models against the present-day hydrochemistry data. The site-descriptive model is subsequently used for engineering design, safety assessment and environmental impact assessment studies. In the safety assessment application, an explicit repository scale DFN model is nested within the regional scale ECPM model and used to assess flow rates in deposition holes and flow paths, including flow-related transport properties along the groundwater paths, from the deposition holes to the biosphere Keywords: Discrete fracture networks, Hydrogeology, Hydrochemistry, 3D Groundwater flow, modelling

  20. Hydrogeological characterization of a coastal aquifer in southern Turkey

    NASA Astrophysics Data System (ADS)

    Brehme, M.; Dokuz, U. E.; Scheytt, T.; Çelik, M.

    2012-04-01

    A sustainable use of groundwater resources in the world is of rising importance, especially in areas where groundwater quality and quantity are threatened. Areas in which groundwater has to be treated carefully are for example coastal plains. They are preferential places for settlements and infrastructure routes. Therefore the water may be for example contaminated by seepage of pollutants through soil. Furthermore high amounts of water are withdrawn, often without sustainable water management systems. This can cause saltwater intrusion from the sea. In this study the investigation area covers 45 km2 of a coastal plain near Dörtyol in southern Turkey. Bounded by the Amanos Mountains to the East and the Mediterranean Sea to the west human activities are concentrated in this area. Agriculture as main land use, as well as the development of industry and the increasing importance of the geographical position as transition point between Europe and Middle East characterize this setting. It is threatened by saltwater intrusion due to high amounts of withdrawn water, as well as by anthropogenic compounds entering the aquifer. A detailed knowledge and understanding are essential to avoid destabilisation of such systems. During a fieldwork in 2008 34 groundwater and 7 surface water samples were taken from wells and rivers. Physicochemical parameters, groundwater level measurements, and discharge loggings were done at various places in the study area. The water was analysed for major ions by inductively coupled plasma optical emission spectrometry and atomic absorption spectrometry. Studies in the field also included geological mapping of shallow geological layers and geometrical structures. The impermeable basement of the coastal plain is composed of serpentinites and limestones from Mesozoic. Heterogenic tertiary and quaternary sediments composed of rocks from the Amanos Mountain formation cover the basement. This classification including observations of shallow permeable and impermeable layers as well as wetlands in the field allow the localisation of recharge and discharge zones. All sampled wells show similar water chemistry. However, areas of higher concentrations of nitrate (up to 45 mg/L) and sulphate (42 mg/L) can be distinguished, which is a hint of intensive agricultural influence including the use of fertiliser. Generally, the hydrochemistry of the groundwater is characterized by anthropogenic but also geological influence. Remarkable high magnesium concentrations (up to 81 mg/L) at several locations in the area show the influence of water-rock interaction. Ferromagnesian ions are dissolved from serpentinites while increased calcium concentrations result from limestone-dissolution. Relatively low electrical conductivity values and chloride concentrations even in wells near the coast indicate that saltwater intrusion has not yet taken place. Anyway groundwater level measurements compared to former measurements suggest a future intrusion in case the water use remains constant at a high level. This investigation enhances the understanding of the hydrogeological characteristics in this special area and of forthcoming problems in coastal areas in general. However, more emphasis and research is needed including long-term observation of ground- and surface water quality as well as a detailed investigation of hydraulic characteristics of the local aquifer to guarantee a sustainable groundwater use.

  1. Statewide Characterization of Bedrock Fractures in Connecticut for Hydrogeologic Purposes

    NASA Astrophysics Data System (ADS)

    Burton, W. C.; Stone, J. R.; Walsh, G. J.; Starn, J. J.

    2003-12-01

    The State of Connecticut relies on wells bored into fractured bedrock for most of its domestic drinking-water supplies, and there is concern about how best to characterize the source areas for these wells and protect them from contamination. Roughly three-quarters of the State is underlain by metamorphosed sedimentary and igneous rocks in the form of schists and gneisses; the remainder is underlain by clastic sedimentary rocks and basalt flows of the early Mesozoic Hartford and Pomperaug basins. Unconsolidated surficial deposits of variable thickness from the Pleistocene continental glaciation overlie most of the bedrock. Aquifer tests indicate that the surficial deposits constitute the most productive reservoir for ground water but that joint sets in bedrock constitute the most important pathways for ground-water flow to bedrock wells. Single near-vertical joint sets in bedrock may produce elliptical zones of contribution to wells having long axes that are parallel to the fracture trend. Bedrock geologic maps at 1:24,000 scale have been published for nearly all of the State, so lithologic units and formations have well-known distributions and foliation patterns, although fracture data are limited. If the fracturing habit of each formation is internally consistent with respect to foliation, however, then a limited number of observations of each formation should allow us to infer the approximate nature and orientations of the dominant bedrock fracture sets throughout the State from published geologic maps. We are currently analyzing representative outcrops of each of the major bedrock formations in the State to determine the relationship between the degree and nature of foliation and the orientation and intensity of associated fracture sets. Our preliminary observations indicate that the most fundamental difference is between layered and nonlayered rocks. Layered rocks, including schists, gneisses, and the early Mesozoic clastic sedimentary rocks, commonly have a dominant layer-parallel joint set, or parting, aligned along pre-existing rock fabric including foliation, compositional layering, or bedding. The degree of development of this parting can vary depending on such variables as lithology and the presence or absence of tectonic folds. In many of these rocks, a second set of near-vertical joints is developed orthogonal to the strike of foliation and parallel to dip direction. In both the layered and the nonlayered rock types, a third set of unroofing joints is developed subparallel to the land surface and decreases in intensity with depth; in areas with gently dipping foliation or layering, these unroofing joints develop along foliation parting. The early Mesozoic basalts, which are classified as nonlayered, have well-developed cooling joints. A hydrogeologic map of the State of Connecticut depicting these bedrock fracture characteristics and their dominant trends will be useful to State and local managers concerned with the protection of ground-water supplies.

  2. 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.

  3. Hydrogeologic Framework of Bedrock Units and Initial Salinity Distribution for a Simulation of Groundwater Flow for the Lake Michigan Basin

    USGS Publications Warehouse

    Lampe, David C.

    2009-01-01

    The U.S. Geological Survey is assessing groundwater availability in the Lake Michigan Basin. As part of the assessment, a variable-density groundwater-flow model is being developed to simulate the effects of groundwater use on water availability throughout the basin. The hydrogeologic framework for the Lake Michigan Basin model was developed by grouping the bedrock geology of the study area into hydrogeologic units on the basis of the functioning of each unit as an aquifer or confining layer within the basin. Available data were evaluated based on the areal extent of coverage within the study area, and procedures were established to characterize areas with sparse data coverage. Top and bottom altitudes for each hydrogeologic unit were interpolated in a geographic information system for input to the model and compared with existing maps of subsurface formations. Fourteen bedrock hydrogeologic units, making up 17 bedrock model layers, were defined, and they range in age from the Jurassic Period red beds of central Michigan to the Cambrian Period Mount Simon Sandstone. Information on groundwater salinity in the Lake Michigan Basin was compiled to create an input dataset for the variable-density groundwater-flow simulation. Data presented in this report are referred to as 'salinity data' and are reported in terms of total dissolved solids. Salinity data were not available for each hydrogeologic unit. Available datasets were assigned to a hydrogeologic unit, entered into a spatial database, and data quality was visually evaluated. A geographic information system was used to interpolate salinity distributions for each hydrogeologic unit with available data. Hydrogeologic units with no available data either were set equal to neighboring units or were vertically interpolated by use of values from units above and below.

  4. 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.

  5. Hydrogeologic Framework in Three Drainage Basins in the New Jersey Pinelands, 2004-06

    USGS Publications Warehouse

    Walker, Richard L.; Reilly, Pamela A.; Watson, Kara M.

    2008-01-01

    The U.S. Geological Survey, in cooperation with the New Jersey Pinelands Commission, began a multi-phase hydrologic investigation in 2004 to characterize the hydrologic system supporting the aquatic and wetland communities of the New Jersey Pinelands area (Pinelands). The Pinelands is an ecologically diverse area in the southern New Jersey Coastal Plain underlain by the Kirkwood-Cohansey aquifer system. The demand for ground water from this aquifer system is increasing as local development increases. To assess the effects of ground-water withdrawals on Pinelands stream and wetland water levels, three drainage basins were selected for detailed hydrologic assessments, including the Albertson Brook, McDonalds Branch and the Morses Mill Stream basins. Study areas were defined surrounding the three drainage basins to provide sub-regional hydrogeologic data for the ground-water flow modeling phase of this study. In the first phase of the hydrologic assessments, a database of hydrogeologic information and a hydrogeologic framework model for each of the three study areas were produced. These framework models, which illustrate typical hydrogeologic variations among different geographic subregions of the Pinelands, are the structural foundation for predictive ground-water flow models to be used in assessing the hydrologic effects of increased ground-water withdrawals. During 2004-05, a hydrogeologic database was compiled using existing and new geophysical and lithologic data including suites of geophysical logs collected at 7 locations during the drilling of 21 wells and one deep boring within the three study areas. In addition, 27 miles of ground-penetrating radar (GPR) surface geophysical data were collected and analyzed to determine the depth and extent of shallow clays in the general vicinity of the streams. On the basis of these data, the Kirkwood-Cohansey aquifer system was divided into 7 layers to construct a hydrogeologic framework model for each study area. These layers are defined by their predominant sediment textures as aquifers and leaky confining layers. The confining layer at the base of the Kirkwood-Cohansey aquifer system, depending on location, is defined as one of two distinct clays of the Kirkwood Formation. The framework models are described using hydrogeologic sections, maps of structure tops of layers, and thickness maps showing variations of sediment textures of the various model layers. The three framework models are similar in structure but unique to their respective study areas. The hydraulic conductivity of the Kirkwood-Cohansey aquifer system in the vicinity of the three study areas was determined from analysis of 16 slug tests and 136 well-performance tests. The mean values for hydraulic conductivity in the three study areas ranged from about 84 feet per day to 130 feet per day. With the exception of the basal confining layers, the variable and discontinuous nature of clay layers within the Kirkwood-Cohansey aquifer system was confirmed by the geophysical and lithologic records. Leaky confining layers and discontinuous clays are generally more common in the upper part of the aquifer system. Although the Kirkwood-Cohansey aquifer system generally has been considered a water-table aquifer in most areas, localized clays in the aquifer layers and the effectiveness of the leaky confining layers may act to impede the flow of ground water in varying amounts depending on the degree of confinement and the location, duration, and magnitude of the hydraulic stresses applied. Considerable variability exists in the different sediment textures. The extent to which this hydrogeologic variability can be characterized is constrained by the extent of the available data. Thus, the hydraulic properties of the modeled layers were estimated on the basis of available horizontal hydraulic conductivity data and the range of sediment textures estimated from geophysical and lithologic data.

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

    SciTech Connect

    Feckley, D.L. (Baylor Univ., Waco, TX (United States). 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.

  7. Hydrogeologic performance assessment analysis of the low-level radioactive waste disposal facility near Sheffield, Illinois

    Microsoft Academic Search

    M. P. Bergeron; D. J. Holford; M. L. Kemner; C. J. Hostetler

    1991-01-01

    A hydrogeologic performance assessment was conducted for the commercial low-level radioactive waste disposal site located about 3 miles southwest of the town of Sheffield, in Bureau County, northwestern Illinois. The site has 21 trenches, which contain about 900,000 meters³, of buried waste and about 60,000 curies of nuclear by-product material. The disposal trenches cut through a complex series of Quaternary

  8. 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.

  9. Hydrogeologic framework and ground-water resources at Seymour Johnson Air Force Base, North Carolina

    USGS Publications Warehouse

    Cardinell, A.P.; Howe, S.S.

    1997-01-01

    A preliminary hydrogeologic framework of the Seymour Johnson Air Force Base was constructed from published data, available well data, and reports from Air Base files, City of Goldsboro and Wayne County records, and North Carolina Geological Survey files. Borehole geophysical logs were run in selected wells; and the surficial, Black Creek, and upper Cape Fear aquifers were mapped. Results indicate that the surficial aquifer appears to have the greatest lateral variability of clay units and aquifer material of the three aquifers. A surficial aquifer water-level surface map, constructed from selected monitoring wells screened exclusively in the surficial aquifer, indicates the general direction of ground-water movement in this mostly unconfined aquifer is toward the Neuse River and Stoney Creek. However, water-level gradient data from a few sites in the surficial aquifer did not reflect this trend, and there are insufficient hydrologic and hydrogeologic data to determine the cause of these few anamalous measurements. The Black Creek aquifer underlies the surficial aquifer and is believed to underlie most of Wayne County, including the Air Base where the aquifer and overlying confining unit are estimated from well log data to be as much as 100 feet thick. The Black Creek confining unit ranges in thickness from less than 8 feet to more than 20 feet. There are currently no accessible wells screened exclusively in the Black Creek aquifer from which to measure water levels. The upper Cape Fear aquifer and confining unit are generally found at depths greater than 80 feet below land surface at the Air Base, and are estimated to be as much as 70 feet thick. Hydrologic and hydrogeologic data are insufficient to determine localized surficial aquifer hydrogeology, ground-water movement at several sites, or hydraulic head differences between the three aquifers.

  10. 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.

  11. 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.

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

    Microsoft Academic Search

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

    2008-01-01

    A hydrogeological study was conducted in Potsdam sandstones on the international border between Canada (Quebec) and the USA\\u000a (New York). Two sandstone formations, arkose and conglomerate (base) and well-cemented quartz arenite (upper), underlie the\\u000a study area and form the major regional aquifer unit. Glacial till, littoral sand and gravel, and marine silt and clay discontinuously\\u000a overlie the aquifer. In both

  13. Hydrogeology of the Kabul Basin (Afghanistan), part I: aquifers and hydrology

    Microsoft Academic Search

    Georg Houben; Nadege Niard; Torge Tünnermeier; Thomas Himmelsbach

    2009-01-01

    Shallow groundwater represents the main source for water supply in Kabul, Afghanistan. Detailed information on the hydrogeology\\u000a of the Kabul Basin is therefore needed to improve the current supply situation and to develop a sustainable framework for\\u000a future groundwater use. The basin is situated at the intersection of three major fault systems of partially translational\\u000a and extensional character. It comprises

  14. 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.

  15. 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.

  16. 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.

  17. Dynamic interactions between hydrogeological and exposure parameters in daily dose prediction under uncertainty and temporal variability.

    PubMed

    Kumar, Vikas; de Barros, Felipe P J; Schuhmacher, Marta; Fernàndez-Garcia, Daniel; Sanchez-Vila, Xavier

    2013-12-15

    We study the time dependent interaction between hydrogeological and exposure parameters in daily dose predictions due to exposure of humans to groundwater contamination. Dose predictions are treated stochastically to account for an incomplete hydrogeological and geochemical field characterization, and an incomplete knowledge of the physiological response. We used a nested Monte Carlo framework to account for uncertainty and variability arising from both hydrogeological and exposure variables. Our interest is in the temporal dynamics of the total dose and their effects on parametric uncertainty reduction. We illustrate the approach to a HCH (lindane) pollution problem at the Ebro River, Spain. The temporal distribution of lindane in the river water can have a strong impact in the evaluation of risk. The total dose displays a non-linear effect on different population cohorts, indicating the need to account for population variability. We then expand the concept of Comparative Information Yield Curves developed earlier (see de Barros et al. [29]) to evaluate parametric uncertainty reduction under temporally variable exposure dose. Results show that the importance of parametric uncertainty reduction varies according to the temporal dynamics of the lindane plume. The approach could be used for any chemical to aid decision makers to better allocate resources towards reducing uncertainty. PMID:24011618

  18. The Yarkon-Taninim groundwater basin, Israel hydrogeology: case study and critical review

    NASA Astrophysics Data System (ADS)

    Weinberger, G.; Rosenthal, E.; Ben-Zvi, A.; Zeitoun, D. G.

    1994-09-01

    The late Albian-Turonian Judea Group carbonate aquifer is one of the most important resources of fresh groundwater in the northern Negev and in the central part of Israel. Over three decades ago, various hydrological, hydrochemical, hydrometeorological and geological aspects of this aquifer were thoroughly investigated and served to build up the professional background and data base for the management of this resource. Notwithstanding the accumulating structural, hydrogeological and hydrochemical evidence, the conceptual hydrogeological model of the Yarkon-Taninim basin (which constitutes the western part of the Judea Group aquifer) has neither been questioned nor updated. Therefore, the existing and accepted model of this basin should in the best case only depict general features and trends. The present review critically examines the main hitherto accepted hydrogeological conventions, points out puzzling and contradictory phenomena and emphasizes questionable issues. Although the present review deals with problems related to a specific groundwater basin, the methods and effort for breaking long-established conventions may serve as an example for similar situations, in other places, in which water resources are managed according to long-established concepts and traditions without being periodically revised and reassessed in view of accumulating knowledge.

  19. Applying Time-Frequency Analysis to Assist Identification of Hydrogeological Structure of Groundwater Aquifers

    NASA Astrophysics Data System (ADS)

    shiuan, C. W.; Chang, L.

    2013-12-01

    Due to global warming, climate change, and economic development, the stability of water supply is challenged using only surface water resources. Hence, groundwater becomes an important water resource for increasing water supply reliability. However, groundwater extraction many introduce damages such as land subsidence and seawater intrusion. To accurately evaluate the response of groundwater aquifers, correct hydrogeological structure is a key factor. In the past, the evaluation of the hydrogeological structure relies on subjective judgment which is arbitrarily made based on available information of core sampling record, fossils, geological dating, etc. This study develops a quantitative method to provide objective information for improving the judgment. This method uses observed groundwater water level and time-frequency analysis. Precisely, the signal strength of the groundwater level is evaluated using Fast Fourier Transform (FFT) which is done by a commercially available software named Visual Signal. Two signal frequencies, daily and annual frequency, are studied. This method is applied to Lanyang Plain in Taiwan. The groundwater level record of shallow wells is selected for the signal processing. Therefore, higher signal strength of an annual signal indicates higher recharge which is an indicator of unconfined aquifer. In the case of Lanyang Plain, the low signal strength area includes fan top area and scatter areas at fan central and fantail areas. This signal information along with core sampling information can provide a complete picture of the hydrogeological structure and characteristics for the studied area Ilan shallow water wells in different frequencies

  20. A review of the hydrogeologic-geochemical model for Cerro Prieto

    USGS Publications Warehouse

    Lippmann, M.J.; Truesdell, A.H.; Halfman-Dooley, S. E.; Mañónm, A.

    1991-01-01

    With continued exploitation of the Cerro Prieto, Mexico, geothermal field, there is increasing evidence that the hydrogeologic model developed by Halfman and co-workers presents the basic features controlling the movement of geothermal fluids in the system. In mid-1987 the total installed capacity at Cerro Prieto reached 620 MWc, requiring a large rate of fluid production (more than 10,500 tonnes/hr of a brine-steam mixture; August 1988). This significant mass extraction has led to changes in reservoir thermodynamic conditions and in the chemistry of the produced fluids. Pressure drawdown has caused an increase in cold water recharge in the southern and western edges of the field, and local and general reservoir boiling in parts of the geothermal system. After reviewing the hydrogeologic and geochemical models of Cerro Prieto, the exploitation-induced cold water recharge and reservoir boiling (and plugging) observed in different areas of the field, are discussed and interpreted on the basis of these models and schematic flow models that describe the hydrogeology. ?? 1991.

  1. 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.

  2. 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.

  3. Flow and transport in unsaturated fractured rock: effects of multiscale heterogeneity of hydrogeologic properties.

    PubMed

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

    2003-01-01

    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% 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. PMID:12498572

  4. 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.

  5. The use of ecohydrological groundwater indicator plants in hydrogeological conceptual models

    NASA Astrophysics Data System (ADS)

    Lewis, J.

    2011-12-01

    Many plant species have been used for millennia as indicators of subsurface water. Under favorable circumstances, such ecohydrological indicators can suggest groundwater discharge areas, the depth to groundwater and the degree of mineralization. This information is available at virtually no expense and therefore has the potential to cost-effectively contribute to hydrogeological conceptual site models. However, very few hydrogeological studies take advantage of this inexpensive source of data. This review focuses on woody plants that are easily identified by earth scientists with little botanical training. Both facultative and obligate phreatophyte species are discussed. Riparian vegetation, being often found in groundwater discharge areas is covered in depth. The majority of published research concerning phreatophytes comes from the arid and semi-arid environments of the southwestern United States. However, this paper makes an effort to draw on data from several regions of the world and several fields of study. This includes a substantial body of research into geobotany from the former Soviet Union which has been largely overlooked by Western scholars. One of the most significant obstacles to using ecohydrological indicators in hydrogeological conceptual models is simply locating relevant information. Little has been published concerning indicator species in temperate, boreal and tropical zones. As a result, there is less useful information that can be deduced from groundwater indicator species in these climates. This article reviews both the state of the art and the potential for appliying ecohydrological groundwater indicator species to groundwater conceptual models. We conclude that ecohydrological groundwater indicators currently have the potential to cost effectively contribute to groundwater conceptual models in arid and semi-arid riparian zones. In climates that have an excess of moisture, extracting useful information from indicator species may require some botanical training, but is still possible.

  6. 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.

  7. 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.

  8. Service Learning and Local Hydrogeology in the Classroom: An example from Anchorage, Alaska

    NSDL National Science Digital Library

    LeeAnn Munk

    This project is designed to introduce students to a local hydrogeologic problem or issue of interest to the community. The project requires the students to learn about their local groundwater environment and apply principles and concepts that they learn in the classroom to an issue that is of concern to the public. This project provides a good introduction to "real world" problems that the students are likely to encounter as professionals. Students are required to synthesize information from a variety of sources and develop their own assessment of the problem and also to make recommendations based on their professional opinions.

  9. Introduction: Special Issue: Discussions on Metahydrogeology: Research Stocktaking or Identity Crisis? Essays on the Once and Future Merit of Research in Hydrogeology

    Microsoft Academic Search

    Timothy R. Ginn; Timothy D. Scheibe

    2008-01-01

    We believe that the Journal of Hydrologic Engineering should serve as the primary outlet for hydrogeological research on the engineering aspectsincluding applications and scienceof subsurface hydrology. Our journal fills the interval between the more theoretical and the more applied contexts of hydrogeology for which numerous print outlets exist. We begin drawing together our strategy for invigorating this role in the

  10. MODFLOW-2000, the U.S. Geological Survey modular ground-water model -- Three additions to the Hydrogeologic-Unit Flow (HUF) Package: Alternative storage for the uppermost active cells, Flows in hydrogeologic units, and the Hydraulic-coductivity depth-dependence (KDEP) capability

    USGS Publications Warehouse

    Anderman, Evan R.; Hill, Mary C.

    2003-01-01

    The Hydrogeologic-Unit Flow (HUF) Package is an internal flow package for MODFLOW-2000 that allows the vertical geometry of the system hydrogeology to be defined differently than the definition of model layers. Effective hydraulic properties for the model layers are calculated using the hydraulic properties of the hydrogeologic units. The HUF Package can be used instead of the Block-Centered Flow (BCF) or the Layer Property Flow (LPF) Packages. This report documents three additions to the HUF Package.

  11. 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

  12. 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)

  13. 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.

  14. Storage of low-level radioactive wastes in the ground; hydrogeologic and hydrochemical factors

    USGS Publications Warehouse

    Papadopulos, Stavros Stefanu; Winograd, Isaac Judah

    1974-01-01

    The status of mathematical simulation techniques, as they apply to radioactive waste burial sites, is briefly reviewed, and hydrogeologic and hydrochemical data needs are listed in order of increasing difficulty and cost of acquisition. Predictive modeling, monitoring, and management of radionuclides dissolved and transported by ground water can best be done for sites in relatively simple hydrogeologic settings; namely, in unfaulted relatively flat-lying strata of intermediate permeability such as silt, siltstone and silty sandstone. In contrast, dense fractured or soluble media, and poorly permeable porous media (aquitards) are not suitable for use as burial sites, first because of media heterogeneity and difficulties of sampling, and consequently of predictive modeling, and second, because in humid zones burial trenches in aquitards may overflow. A buffer zone several thousands of feet to perhaps several miles around existing or proposed sites is a mandatory consequence of the site selection criteria. As a specific example, the Maxey Flats, Kentucky low-level waste disposal site is examined. (Woodard-USGS)

  15. Hydrogeology and soil gas at J-Field, Aberdeen Proving Ground, Maryland

    USGS Publications Warehouse

    Hughes, W.B.

    1993-01-01

    Disposal of chemical warfare agents, munitions, and industrial chemicals in J-Field, Aberdeen Proving Ground, Maryland, has contaminated soil, groundwater 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 contaminants. The geologic units beneath J-Field consist of Coastal Plain sediments of the Cretaceous Patapsco Formation and Pleistocene Talbot Formation. The Patapsco Formation contains several laterally discontinuous aquifers and confining units. The Pleistocene deposits were divided into 3 hydrogeologic units--a surficial aquifer, a confining unit, and a confined aquifer. 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. In offshore areas, water flows from the deeper confined aquifers upward toward discharge areas in the Gunpowder River and Chesapeake Bay. Analyses of soil-gas samples showed 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. The highest flux values were located downgradient of the toxic materials and white phosphorus disposal areas, indicating that groundwater contaminants are moving from source areas beneath the disposal pits toward discharge points in the marshes and estuaries. Elevated relative-flux values were measured upgradient and downgradient of the riot-control agent disposal area, and possibly result from soil and (or) groundwater contamination.

  16. Hydrogeological modeling of submarine groundwater discharge on the continental shelf of Louisiana

    NASA Astrophysics Data System (ADS)

    Thompson, Craig; Smith, Leslie; Maji, Roudrajit

    2007-03-01

    A regional scale hydrogeologic model has been developed to estimate the magnitude of submarine groundwater discharge to the coastal waters of southeastern Louisiana. The model domain incorporates both the onshore recharge area of terrestrially derived freshwater, and fluid circulation within the sediments on the continental shelf. The hydrogeologic properties of these sediments, which form part of the Coastal Lowlands Aquifer System, have been well-characterized in earlier studies. The low topographic relief of the coastal plain and an extensive zone of seawater intrusion are key features of the groundwater flow system. Model calculations suggest that no water containing a substantial component of terrestrial origin discharges on the continental shelf. Rather the near-shore coastal zone serves as a groundwater recharge area of saline water that then forms the seawater recirculation system beneath the coastal plain. The modeling results are consistent with interpretations of the rates of submarine groundwater discharge derived from geochemical tracers, presented in a companion paper by McCoy et al. (2007).

  17. Satellite earth observation as a tool to conceptualize hydrogeological fluxes in the Sandveld, South Africa

    NASA Astrophysics Data System (ADS)

    M?nch, Zahn; Conrad, Julian E.; Gibson, Lesley A.; Palmer, Anthony R.; Hughes, Denis

    2013-08-01

    In semi-arid, groundwater-dependent regions of South Africa, allocation of additional water resources can become problematic in the absence of quantified regional groundwater recharge values. In this study in the northern Sandveld, remote-sensing-data products for precipitation ( P) and evapotranspiration (ET) are used to quantify groundwater recharge and guide the conceptualization of the hydrogeology of the study area. Data from three ET models (ETMODIS, MOD16, Pitman rainfall-runoff) are compared; these models concur best in years of average rainfall, with model results deviating up to 30 % in wet years. The MODIS data product (MOD16) is used in conjunction with gridded precipitation data to calculate spatial regional recharge. The long-term precipitation minus evapotranspiration ( P-ET) budget closes on a positive 13 ± 25 %; however, when correcting ET (20 % underestimation determined using the chloride mass balance method), the catchment average potential recharge is reduced to -4 ± 30 %. The use of P-ET clearly identifies potential recharge zones at higher elevation and discharge zones, highlighting irrigated agriculture. The usefulness of identifying recharge zones is demonstrated in the value added to conceptualizing the hydrogeology. Since some uncertainty around the accuracy of ET data still remains, it is recommended that the MODIS data product be validated more comprehensively in semi-arid environments.

  18. Tritium/3He measurements in young groundwater: Progress in applications to complex hydrogeological systems

    USGS Publications Warehouse

    Schlosser, P.; Shapiro, S.D.; Stute, M.; Plummer, N.

    2000-01-01

    Tritium/3He dating has been applied to many problems in groundwater hydrology including, for example, determination of circulation patterns, mean residence times, recharge rates, or bank infiltration. Here, we discuss recent progress in the application of the tritium/3He dating method to sites with complex hydrogeological settings. Specifically, we report on tritium/3He dating at sites with (a) river infiltration into the basaltic fractured rock aquifer of the Eastern Snake River Plain, and (b) river infiltration through sinkholes into the karstic limestone Upper Floridian aquifer near Valdosta, Georgia.Tritium/3He dating has been applied to many problems in groundwater hydrology including, for example, determination of circulation patterns, mean residence times, recharge rates, or bank infiltration. Here, we discuss recent progress in the application of the tritium/3He dating method to sites with complex hydrogeological settings. Specifically, we report on tritium/3He dating at sites with (a) river infiltration into the basaltic fractured rock aquifer of the Eastern Snake River Plain, and (b) river infiltration through sinkholes into the karstic limestone Upper Floridian aquifer near Valdosta, Georgia.

  19. Water-management failure under complex hydrogeological conditions in the Kolubara District, Serbia

    NASA Astrophysics Data System (ADS)

    Dokmanovi?, Petar B.; Niki?, Zoran N.; Kruni?, Olivera Z.; Petrovi?, Branislav Z.

    2012-09-01

    The design of the Rovni Lake reservoir in the Kolubara District, western Serbia, is the basis for the regional water-supply system there. The design was promoted as an example of integrative and sustainable water management, with regard to the planned provision for long-term municipal water supply in the Kolubara region, as well as for the regulation of the downstream river flow. Hydrogeological analyses, however, have indicated three key issues that contest this sustainable water-management model: (1) the capability of the available groundwater sources to fully meet the drinking water demands in the region, (2) a pronounced risk of water loss from the reservoir, and (3) a pronounced risk of karst aquifer contamination. The Rovni project ignores the hydrogeological properties of a karst aquifer and thereby needlessly threatens the groundwater resource. Hence, modifications to the project are recommended in order to mitigate or eliminate the most significant construction and ecological risk factors and to improve sustainable exploitation and integrative water-resource management.

  20. Hydrogeology of a hazardous-waste disposal site near Brentwood, Williamson County, Tennessee

    USGS Publications Warehouse

    Tucci, Patrick; Hanchar, D.W.; Lee, R.W.

    1990-01-01

    Approximately 44,000 gal of industrial solvent wastes were disposed in pits on a farm near Brentwood, Tennessee, in 1978, and contaminants were reported in the soil and shallow groundwater on the site in 1985. In order for the State to evaluate possible remedial-action alternatives, an 18-month study was conducted to define the hydrogeologic setting of the site and surrounding area. The area is underlain by four hydrogeologic units: (1) an upper aquifer consisting of saturated regolith, Bigby-Cannon Limestone, and weathered Hermitage Formation; (2) the Hermitage confining unit; (3) a lower aquifer consisting of the Carters Limestone; and (4) the Lebanon confining unit. Wells generally are low yielding less than 1 gal/min ), although locally the aquifers may yield as much as 80 gal/minute. This lower aquifer is anisotropic, and transmissivity of this aquifer is greatest in a northwest-southeast direction. Recharge to the groundwater system is primarily from precipitation, and estimates of average annual recharge rates range from 6 to 15 inches/year. Discharge from the groundwater system is primarily to the Little Harpeth River and its tributaries. Groundwater flow at the disposal site is mainly to a small topographic depression that drains the site. Geochemical data indicate four distinct water types. These types represent (1) shallow, rapidly circulating groundwater; (2) deeper (> than 100 ft), rapidly circulating groundwater; (3) shallow, slow moving groundwater; and (4) deeper, slow moving groundwater. Results of the numerical model indicate that most flow is in the upper aquifer. (USGS)

  1. 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

  2. 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

  3. A Comparison of Hydrogeologic Models, Tritium\\/helium-3, and Deliberate Tracer Experiments to Understand Ground Water Residence Time

    Microsoft Academic Search

    J. McDermott; J. Clark; D. Avisar; G. Hudson

    2005-01-01

    Assessment of subsurface residence time of ground water, used for determining flow paths and travel times, is an important criterion for understanding and monitoring water quality and in situ biogeochemical reactions. Established methods of determining travel time include hydrogeologic modeling, transient tracers and deliberate tracers. This paper presents a comparison of these three methods near the Montebello Forebay recharge site

  4. Hydrogeologic Characterization of Fractured Crystalline Bedrock on the Southern Part of Manhattan, New York, Using Advanced Borehole Geophysical Methods

    Microsoft Academic Search

    F. Stumm; A. Chu; P. K. Joesten

    2007-01-01

    ABSTRACT. Advanced borehole-geophysical methods were used to assess the hydrogeology of fractured crystalline bedrock in 31 of 64 boreholes on the southern part of Manhattan Island, N.Y. The majority of boreholes penetrated gneiss, schist, and other crystalline bedrock, and had an average depth of 591 ft (180 m) below land surface (BLS). In this study we use a combination of

  5. Hydrochemical–isotopic and hydrogeological conceptual model of the Las Tres V??rgenes geothermal field, Baja California Sur, México

    Microsoft Academic Search

    E. Portugal; P. Birkle; R. M. Barragán R; V. M. Arellano G; E. Tello; M. Tello

    2000-01-01

    Based on geological, structural, hydrochemical and isotopic data, a hydrogeological conceptual model for the geothermal reservoir, shallow wells and springs at the Las Tres V??rgenes geothermal field and its surroundings is proposed. The model explains the genesis of different types of thermal and cold groundwater in the NW (El Azufre Valley, Las Tres V??rgenes and Aguajito complex), NE (Reforma complex)

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

    SciTech Connect

    NONE

    1996-02-01

    This annual groundwater quality report (GWQR) contains groundwater and surface water quality data obtained during the 1995 calendar year (CY) at several hazardous and nonhazardous waste management facilities associated with the Y-12 Plant located on the DOE Oak Ridge Reservation (ORR) southeast of Oak Ridge, Tennessee. The sites addressed by this document are located in Bear Creek Valley (BCV) west of the Y-12 Plant complex within the Bear Creek Hydrogeologic Regime. The Bear Creek Regime is one of three hydrogeologic regimes defined for the purposes of groundwater and surface water quality monitoring at the Y-12 Plant. The purpose of the Groundwater Protection Program (GWPP) is to characterize the hydrogeology and to monitor groundwater quality at the Y-12 Plant and surrounding area to provide for protection of groundwater resources consistent with federal, state, and local requirements. Part 1 (this report) consists primarily of data appendices and serves as a reference for the groundwater quality data obtained each CY under the lead of the Y-12 Plant GWPP. Part 2 of the report, to be issued mid-year, will contain an evaluation of the data with respect to regime-wide groundwater quality, present the findings and status of ongoing hydrogeologic studies, describe changes in monitoring priorities, and present planned modifications to the groundwater sampling and analysis program for the following CY.

  7. User Guide for HUFPrint, A Tabulation and Visualization Utility for the Hydrogeologic-Unit Flow (HUF) Package of MODFLOW

    USGS Publications Warehouse

    Banta, Edward R.; Provost, Alden M.

    2008-01-01

    This report documents HUFPrint, a computer program that extracts and displays information about model structure and hydraulic properties from the input data for a model built using the Hydrogeologic-Unit Flow (HUF) Package of the U.S. Geological Survey's MODFLOW program for modeling ground-water flow. HUFPrint reads the HUF Package and other MODFLOW input files, processes the data by hydrogeologic unit and by model layer, and generates text and graphics files useful for visualizing the data or for further processing. For hydrogeologic units, HUFPrint outputs such hydraulic properties as horizontal hydraulic conductivity along rows, horizontal hydraulic conductivity along columns, horizontal anisotropy, vertical hydraulic conductivity or anisotropy, specific storage, specific yield, and hydraulic-conductivity depth-dependence coefficient. For model layers, HUFPrint outputs such effective hydraulic properties as horizontal hydraulic conductivity along rows, horizontal hydraulic conductivity along columns, horizontal anisotropy, specific storage, primary direction of anisotropy, and vertical conductance. Text files tabulating hydraulic properties by hydrogeologic unit, by model layer, or in a specified vertical section may be generated. Graphics showing two-dimensional cross sections and one-dimensional vertical sections at specified locations also may be generated. HUFPrint reads input files designed for MODFLOW-2000 or MODFLOW-2005.

  8. Calibrating hydrogeologic parameters for the 3-D site-scale unsaturated zone model of Yucca Mountain, Nevada

    Microsoft Academic Search

    T. M. Bandurraga; G. S. Bodvarsson

    1999-01-01

    An important issue in the evaluation of the unsaturated zone (UZ) at Yucca Mountain, Nevada is the calibration of the parameters used in the 3-D site-scale numerical flow model. The hydrogeologic parameters are calibrated using an inversion code (ITOUGH2) to fit measured core sample and in situ data according to statistical criteria. The available data include saturations, water potentials, pneumatic

  9. Sediment deformation and hydrogeology of the Nankai Trough accretionary prism: Synthesis of shipboard results of ODP Leg 131

    Microsoft Academic Search

    A. Taira; I. Hill; J. Firth; U. Berner; W. Brückmann; T. Byrne; T. Chabernaud; A. Fisher; J.-P. Foucher; T. Gamo; J. Gieskes; R. Hyndman; D. Karig; M. Kastner; Y. Kato; S. Lallemant; R. Lu; A. Maltman; G. Moore; K. Moran; G. Olaffson; W. Owens; K. Pickering; F. Siena; E. Taylor; M. Underwood; C. Wilkinson; M. Yamano; J. Zhang

    1992-01-01

    The main objective of Leg 131 was to provide data on the deformational processes and associated hydrogeology of the Nankai prism toe. Drilling succeeded, for the first time in the history of ocean drilling, in penetrating the complete sedimentary sequence to basaltic basement, reaching 1327 mbsf (metres below seafloor) with good core recovery (55%). Excellent correlation of the lithology and

  10. Structure and hydrogeological functioning of an insular tropical humid andesitic volcanic watershed: A multi-disciplinary experimental approach

    NASA Astrophysics Data System (ADS)

    Charlier, Jean-Baptiste; Lachassagne, Patrick; Ladouche, Bernard; Cattan, Philippe; Moussa, Roger; Voltz, Marc

    2011-02-01

    SummaryThe aim of the study is to establish an hydrogeological scheme of the structure and the functioning of andesitic volcanic systems in the insular and humid tropical context. A watershed has been instrumented at Féfé in Guadeloupe (French West Indies) in the Lesser Antilles to measure rainfall, runoff and piezometric fluctuations between 2003 and 2006. Given the heterogeneity of the volcanic deposits, a multi-disciplinary approach has been used: a geological and an hydrogeological survey, an hydrodynamic approach (hydraulic tests and signal processing of hydrological time series), and finally, an hydrogeochemical approach (major elements and some trace elements). Two main superposed aquifer respectively in aerial deposits, and in recent nuées ardentes (glowing ash) and lava flows, as well as the underlying aquiclude (the highly weathered older substratum) were identified. At a local scale, some hydrogeological heterogeneities internal to the aquifers were highlighted and related to a polyphased building-up of the geological formations. Hydraulic relationships between the multi-layered aquifers, such as the confinement of the deep aquifer upstream of the basin, were identified. Groundwater/stream exchanges were characterised, detailing various contributions of the shallow and the deep aquifers to stream and spring waters; significant river losses were also observed. At a global scale, within such relatively permeable volcanic formations, the aquifer recharge is about 85% of the annual effective rainfall for an average rainfall year. The hydrogeological scheme appears to be coherent with a geological structure of cut-and-fill paleovalleys frequently observed in andesitic areas. Consequently, groundwater drainage axis are mainly localised in recent nuées ardentes deposits, whereas the inversion of relief characteristic of volcanic areas explains the non-superposition of surface water and groundwater divides and both surface water losses and springs. Finally, this work shows the highly heterogeneous hydrogeological processes occurring in volcanic formations of andesitic-type. It also shows the relationships between the geological structure and the hydrogeological functioning of such basins, and proposes an affordable methodological approach to investigate such a hydrogeological context in depth.

  11. 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.

  12. A Monitoring Platform for Deployment of Sensors for the Hydrogeologic Characterization and Monitoring of Geologic Repositories

    NASA Astrophysics Data System (ADS)

    Black, W. H.; Larssen, D. E.; Mercer, D. G.

    2007-12-01

    Careful and detailed monitoring of hydrogeologic conditions in the subsurface is challenging in any case, but often extremely challenging at the greater depths and in the low-permeability environments typically required for geologic repositories. Much of the recent technological effort associated with deep hydrogeologic characterization has centered on visualization, interpretation and extrapolation of sparsely-arrayed data points; and the data points themselves often come with issues related to quality or defensibility. Such an approach is clearly inadequate to meet the demands and requirements of characterization and risk assessments suitable for deep underground repositories. Perhaps surprisingly some aspects of field procedures and instrumentation used for hydrogeologic studies have seen only slight advances over several decades. However, in other areas significant advances have been made, shedding new light on groundwater behavior and in turn driving further development of the instrumentation and procedures used for characterization and monitoring. This paper discusses some of the challenges of characterizing and monitoring deep, low-permeability groundwater environments. In particular, a technology is described that enables the deployment of a network of pressure/temperature sensors at multiple depths in the subsurface, collection of fluid samples, and execution of a variety of hydraulic tests. The technology is well suited to the deep, low permeability conditions associated with repository projects. Modular monitoring zones can be placed with almost limitless adaptability to subsurface conditions. The system serves as a reliable platform for deployment of retrievable sensors which in most cases have the capability for in-situ calibration checks. Development and advancement of this technology has continued and accelerated through almost 30 years of use on a significant proportion of the geologic repository research projects around the world. Applications have ranged to 1,200 m and more in depth and projects have included the Yucca Mountain Project in the USA, Atomic Energy of Canada's URL in Canada, the Sellafield PNWR in the UK, ANDRA's URL at Bure in France, Japan Atomic Energy Agency's URLs at Mizunami and Horonobe, and sites in South Korea. Results (including long-term monitoring, construction monitoring, data filtering for earth tide analysis, cross-well testing, etc.) from some of these projects will be presented along with a discussion of the evolution of the monitoring technology, lessons learned, current limitations, and a look toward possible future developments.

  13. 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.

  14. Overview of the Hydrogeologic Systems of the Former Homestake Mine, Lead, SD (Invited)

    NASA Astrophysics Data System (ADS)

    Roggenthen, B.

    2013-12-01

    The hydrogeology of the former Homestake Gold Mine is an important consideration, both from a scientific as well as an operational standpoint, because the facility is being converted into an operating underground research laboratory. The long history of mining provided much information about the sources and amounts of the water, as did studies performed during mine closure and subsequent evaluations for the construction of the laboratory. Over 600 km of drifts and shafts were excavated during the 135 year life of the facility, but the water inflow averages only ~44 l/s. All of this water must be either captured at high levels in the facility or pumped from the deeper sumps. Hydrogeologic systems operate on several scales in the Homestake underground. The Precambrian phyllites, schists, quartzites, and amphibolites of the subsurface have nearly no matrix permeability. Water flow is confined to fractures, most of which are quite small, but larger fractures and shear zones have been encountered at depth that produced significant amounts of water. In general, fractures tend to be vertical with few horizontal connections in the areas studied during more recent times. Much of the water inflow in the upper part of the facility originates from surface waters that are introduced into the underground through runoff into an adjacent and overlying open pit. At the 4850 Level, which is the location of the current laboratory (depth of 1.5 km), water chemistry suggests that most of the water is part of a ground water system and impact from surface waters is less. Although deeper portions of the facility are not currently accessible, previous reports indicated that water chemistry in these areas was substantially different from that found at the 4850 Level or from the surface waters. Within the flooded portion of the underground it appears that a circulation system was established involving the mine waters themselves and resulted from geothermal heating in the deeper parts of the workings (up to 2.4 km depth). During the time when the underground workings were filled with water prior to the development of the current laboratory, a logging and sampling program was conducted via the #6 Winze that allowed access to the deeper, flooded areas. This study suggested that the water in the #6 Winze was downcast (moving downward) implying that the water in the underground was being heated and moving upwards by convection through other winzes and passages. Therefore, the water in the underground at Homestake has multiple sources, movement directions, and geochemical/hydrogeologic systems.

  15. 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.

  16. Hydrogeologic maps of proposed flood detention area, Green Swamp area, Florida

    USGS Publications Warehouse

    Rutledge, A.T.; Grubb, Hayes F.

    1978-01-01

    Information about the hydrogeology of that part of the Green Swamp area which has been designated by Southwest Florida Water Management District as the Flood Detention Area is given on seven maps. The maps show (1) core-hole numbers, (2) sand thickness, (3) clay thickness, (4) clay vertical hydraulic conductivity, (5) clay leakance, (6) depth to Floridan aquifer, and (7) altitude of top of Floridan aquifer. The data were obtained from 85 core holes drilled in 1977 and from 24 core hole drilled previously. The 127 square-mile study area is part of the headwaters of the Withlacooche River and the Little Wthlacoochee River. The data will be useful in future water-resources planning and in a concurrent interpretive study of the Green Swamp area. (Woodard-USGS)

  17. 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.

  18. A palaeo-hydrogeological model for arsenic contamination in southern and south-east Asia.

    PubMed

    Stanger, Gordon

    2005-12-01

    An argument is presented in which areas of natural arsenic contamination of modern groundwaters throughout Asia have a common origin. Arsenic originally accumulated in oceanic ferro-manganoan sediments of the eastern Palaeo-Tethys. This was further concentrated through oceanic crustal extinction in what later became the south-east Chinese accreted mineralised terrain. Proto-Himalayan uplift of this area created the palaeo-drainage systems of the Ganges - Brahmaputra, Irrawaddy, Mekong, and Red Rivers, with consequent headwater erosion of arsenic-rich sediments. Their downstream deposition as immature and easily redistributed Neogene sandstones, silts, and iron-rich clays has created secondary and tertiary reservoirs of adsorbed and authigenic arsenic, from which the current arsenic-rich groundwaters have evolved. Considering river basins within the above palaeo-hydrogeological framework provides a basis for assessing the risk of arsenic in groundwater basins of south and south-eastern Asia. PMID:16027970

  19. 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.

  20. 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.

  1. Photogeologic linears as reflecting hydrogeologic regimes of a great sedimentary basin

    SciTech Connect

    Astakhov, V.I. [Institute of Remote Sensing Methods for Geology (VNIIKAM), St. Petersburg (Russian Federation)

    1996-07-01

    The geological significance of linears of various length derived from satellite and airphoto images in the West Siberian sedimentary basin is discussed. A geological signal from deep-seated structures depends on length bands of linears populations. The useful length bands vary depending on the position of a test-site within the basin. The best match between the landscape and deep-seated structural features is obtained in the central part of the basin with great vertical gradients of fluid pressure. The strong hydraulic tensity of a sediment cover is thought to be a prerequisite for minor deep-seated fractures to penetrate through the sedimentary column and distort the normal planetary orientation of short linears on the surface. The hydrogeologic factor is summoned to improve the oscillatory mechanism of fracture propagation.

  2. Identification of rainfall triggering damaging hydrogeological events: a methodological approach applied to Calabria (Italy)

    NASA Astrophysics Data System (ADS)

    Aceto, L.; Petrucci, O.

    2014-09-01

    The paper deals with Damaging Hydrogeological Events (DHEs), defined as periods of severe weather affecting wide regions for several days, and during which landslides and floods cause economic damage and there are victims. The great variability of DHEs in both space and time is the cause of one of the main problems to solve in performing analyses of these events. Dealing with events affecting wide areas for several days, it is problematic to isolate the rainy days that can be considered as factors triggering the observed damaging phenomena. We develop a methodological approach aiming to select and analyse rainfall events that triggered damage. The analysis allows the highlighting of some seasonal characteristics of Calabrian DHEs. The approach can be used for an in-depth analysis leading to the identification of both rainfall thresholds for DHE triggering and rain/damage relationships.

  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. Using hydrogeologic data to evaluate geothermal potential in the eastern Great Basin

    USGS Publications Warehouse

    Masbruch, Melissa D.; Heilweil, Victor M.; Brooks, Lynette E.

    2012-01-01

    In support of a larger study to evaluate geothermal resource development of high-permeability stratigraphic units in sedimentary basins, this paper integrates groundwater and thermal data to evaluate heat and fluid flow within the eastern Great Basin. Previously published information from a hydrogeologic framework, a potentiometric-surface map, and groundwater budgets was compared to a surficial heat-flow map. Comparisons between regional groundwater flow patterns and surficial heat flow indicate a strong spatial relation between regional groundwater movement and surficial heat distribution. Combining aquifer geometry and heat-flow maps, a selected group of subareas within the eastern Great Basin are identified that have high surficial heat flow and are underlain by a sequence of thick basin-fill deposits and permeable carbonate aquifers. These regions may have potential for future geothermal resources development.

  5. Calibration of Spatial Variability of Hydrogeologic Properties in the Unsaturated Fractured Rock at Yucca Mountain, Nevada

    NASA Astrophysics Data System (ADS)

    Zhou, Q.; Bodvarsson, G. S.; Liu, H.; Oldenburg, C. M.

    2001-12-01

    The unsaturated zone at Yucca Mountain, Nevada, consists of alternating sequences of variably fractured and faulted welded and nonwelded tuffs. The geologic formations have been grouped into five hydrostratigraphic units on the basis of welding and contrast of matrix and fracture properties. Rock properties vary significantly between different units, as well as within each unit in the lateral and vertical directions. For the purposes of site-scale hydrologic simulations, the thick unsaturated zone is divided into thirty-five hydrogeologic layers. To characterize the heterogeneity of hydrogeologic properties and to further understand its effects on flow and transport phenomena, a large number of core-scale data have been obtained from deep and shallow boreholes. These data include measurements of state variables (e.g., water saturation, water potential), core-scale properties (e.g., porosity, permeability), and desaturation curves (for capillary parameters) for matrix rocks. Additionally, pneumatic pressure data, air permeability, and fracture mapping data are also available for estimating fracture properties. The calibration of layer-scale matrix and fracture properties is performed in two steps using the inverse modeling code, ITOUGH2. In the first step, all data in different deep boreholes are combined to estimate the mean values of layer-scale rock properties, reducing the uncertainty in the calibration results. In the second step, lateral variability of three most sensitive rock properties (matrix permeability, matrix van Genuchten ? , and fracture permeability) is estimated. The variance of these layer properties is measured by their difference in the calibrated values at different deep boreholes. Calibration results show that matrix permeability varies laterally by three to four orders of magnitude within a geologic unit, in comparison with six to seven orders of magnitude between different hydrostratigraphic units. The lateral variability of fracture permeability is one order of magnitude, while matrix ? is about 1.5 orders of magnitude. The spatial variability of layer-scale rock properties obtained from inverse modeling may be significant to local flow variability.

  6. 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

  7. Hydrogeology of a portion of Yosemite Valley: Groundwater and surface water interaction and conceptual groundwater model

    NASA Astrophysics Data System (ADS)

    Newcomb, N. J.; Fogg, G. E.

    2011-12-01

    A hydrogeologic characterization, monitoring program, and numerical groundwater model were conducted for the Yosemite Valley to assess the impact of groundwater abstraction on streamflow in the Merced River and shallow water table levels. This is the first characterization of the hydrogeology and stream-aquifer interactions in the Yosemite Valley. Analysis of borehole logs, geophysical data, and pump test results suggests that the Yosemite Valley is comprised of at least 2 primary aquifers separated by a clay and silt confining layer. Groundwater is withdrawn from three large diameter wells screened in the deeper aquifer. Drawdown in the water table was measured from 7 piezometers constructed near the abstraction wells during the fall of 2010. Stage in the Merced River was monitored at an upstream and downstream site in the Merced River and a shallow pool in Yosemite Creek. Results from shallow groundwater and surface water monitoring did not show any measurable drawdown or stream depletion in response to groundwater abstraction within typical pumping periods (6 - 14 hrs). Longer term (weeks to months) impacts of groundwater pumping on groundwater levels and streamflow in the Merced River were assessed through numerical modeling using MODFLOW-2000. A conceptual groundwater model of the Yosemite Valley was developed based on existing and collected data. Hypothetical effects of groundwater abstraction were evaluated assuming varied confining layer K. Numerical modeling results suggest that the long term impact of groundwater pumping are primarily restricted to confined units and produce limited stream depletion and drawdown in the unconfined aquifer. However, a more robust spatial and temporal dataset would be required to show this conclusively.

  8. 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.

  9. 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

  10. Hydrogeology and water quality in the Graces Quarters area of Aberdeen Proving Ground, Maryland

    USGS Publications Warehouse

    Tenbus, Frederick J.; Blomquist, Joel D.

    1995-01-01

    Graces Quarters was used for open-air testing of chemical-warfare agents from the late 1940's until 1971. Testing and disposal activities have resulted in the contamination of ground water and surface water. The hydrogeology and water quality were examined at three test areas, four disposal sites, a bunker, and a service area on Graces Quarters. Methods of investigation included surface and borehole geophysics, water-quality sampling, water- level measurement, and hydrologic testing. The hydrogeologic framework is complex and consists of a discontinuous surficial aquifer, one or more upper confining units, and a confined aquifer system. Directions of ground-water flow vary spatially and temporally, and results of site investigations show that ground-water flow is controlled by the geology of the area. The ground water and surface water at Graces Quarters generally are unmineralized; the ground water is mildly acidic (median pH is 5.38) and poorly buffered. Inorganic constituents in excess of certain Federal drinking-water regulations and ambient water-quality criteria were detected at some sites, but they probably were present naturally. Volatile and semivolatile organic com- pounds were detected in the ground water and surface water at seven of the nine sites that were investi- gated. Concentrations of organic compounds at two of the nine sites exceeded Federal drinking-water regulations. Volatile compounds in concentrations as high as 6,000 m/L (micrograms per liter) were detected in the ground water at the site known as the primary test area. Concentrations of volatile compounds detected in the other areas ranged from 0.57 to 17 m/L.

  11. 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.

  12. The Role of Forethought and Serendipity in Designing a Successful Hydrogeological Research Site

    NASA Astrophysics Data System (ADS)

    Shapiro, A. M.; Hsieh, P. A.

    2008-12-01

    Designing and implementing a successful hydrogeologic field research observatory requires careful planning among a multidisciplinary group of research scientists. In addition, a small team of research coordinators needs to assume responsibility for smoothly integrating the multidisciplinary experimental program and promoting the explanation of results across discipline boundaries. A narrow interpretation of success at these hydrogeologic observatories can be viewed as the completion of the field-based experiments and the reporting of results for the field site under investigation. This alone is no small task, given the financial and human resources that are needed to develop and maintain field infrastructure, as well as developing, maintaining, and sharing data and interpretive results. Despite careful planning, however, unexpected or serendipitous results can occur. Such serendipitous results can lead to new understanding and revision of original hypotheses. To fully evaluate such serendipitous results, the field program must collect a broad range of scientifically robust data-beyond what is needed to examine the original hypotheses. In characterizing ground water flow and chemical transport in fractured crystalline rock in the Mirror Lake watershed in central New Hampshire, unexpected effects of scale were observed for hydraulic conductivity and matrix diffusion. Contrary to existing theory, hydraulic conductivity at the site did not increase with scale, whereas the effective coefficient of matrix diffusion was found to increase with scale. These results came to light only after examination of extensive data from carefully designed hydraulic and chemical transport experiments. Experiments were conducted on rock cores, individual fractures and volumes of fractured rock over physical dimensions from meters to kilometers. The interpretation of this data yielded new insight into the effect of scale on chemical transport and hydraulic conductivity of fractured rock. Subsequent evaluation of experiments conducted at other fractured rock sites have showed similarities in hydraulic and chemical transport responses, allowing broader conclusions to be reached concerning geologic controls on ground water flow and chemical transport in fractured rock aquifers.

  13. 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.

  14. Integrating Multiple Subsurface Exploration Technologies in Slope Hydrogeologic Investigation: A Case Study in Taiwan

    NASA Astrophysics Data System (ADS)

    Lo, H.-C.; Hsu, S.-M.; Jeng, D.-I.; Ku, C.-Y.

    2009-04-01

    Taiwan is an island located at a tectonically active collision zone between the Eurasian Plate and the Pacific Plate. Also, the island is in the subtropical climate region with frequent typhoon events that are always accompanied by intense rainfalls within a short period of time. These seismic and climatic elements frequently trigger, directly or indirectly, natural disasters such as landslides on the island with casualties and property damages. Prompted by the urge for minimizing the detrimental effects of such natural disasters, Taiwan government has initiated and funded a series of investigations and studies aimed at better understanding the causes of the natural disasters that may lead to the formulation of more effective disaster contingency plans and possibly some forecasts system. The hydrogeology of a landslide site can help unveil the detention condition of storm water entering the aquifer system of the slope as well as its groundwater condition which, in turn, plays a critical role in slope stability. In this study, a hydrogeologic investigation employing a series of subsurface exploration technologies was conducted at an active landslide site in the vicinity of Hwa Yuan Village in northern Taiwan. The site, which covers an area of approximately 0.14 km2 (35 acres) and generally ranges between 25 to 36 degree in slope, was initially investigated with ground resistivity image profiling (RIP) and electrical logging in order to determine the lithology and possibly the water-bearing capacity of the geologic units beneath the slope surface. Subsequently, both acoustic and optical borehole loggings were then applied to identify potentially significant fracture features at depth and their hydrogeologic implications. In addition, flowmeter loggings and hydraulic packer tests were conducted to further characterize the hydrogeologic system of the site and quantitatively determine the hydraulic properties of major hydrogeologic units. According to the ground resistivity profiles combined with rock core data, the geologic units can be primarily categorized into colluvium and weathered rock at depths of 4-23 m and 23-80 m, respectively. An approximately 20 m shear zone at depths of 45-65 m was found based on the detection outcome of low electrical resistance. Also, according to the borehole electrical logging, the layer of sandstone was identified in the interval of 48-59 m and 68.5-74 m and showed low water-bearing capacity. In addition, the electrical logging identified the layer of shale was in the interval of 59-68.5 m, which possessed a high water-bearing capacity. The velocity profile along the borehole was obtained from the flowmeter logging. A relatively high velocity zone (1.36~2.23 m/min) was measured in the interval of sandstone and relatively low velocity zone (0.12~0.78 m/min) was measured in the interval of shale, which is similar to those found in electrical logging. Moreover, 198 discontinuity planes were identified from the borehole image logging. The orientations of all discontinuities were calculated and compiled to draw a stereographic projection diagram. Judging from the discontinuity clusters on the stereographic projection diagram, a plane failure may possibly occur based on Hoek and Brown's criteria. This is a good demonstration that slope failure geometry and type can be determined by stereographic projection diagram analysis. The borehole images also clearly showed the structures of discontinuities at depth. They not only helped to characterize the results of the above investigation technologies but also provided useful indication in selecting specific geologic intervals for packer tests. The packer tests were conducted and the intervals were isolated based on the results of borehole and flowmeter logging. They indicated that the hydraulic conductivities of the shale and sandstone intervals are respectively 1.37Ã-10-8 m/sec and 2.68Ã-10-5-3.76Ã-10-5 m/sec, which are in good accordance with the hydraulic characteristics inferred by flowmeter logging. The aforementioned investigation results, incl

  15. Hydrogeology of the unsaturated zone, North Ramp area of the Exploratory Studies Facility, Yucca Mountain, Nevada

    USGS Publications Warehouse

    Rousseau, Joseph P., (Edited By); Kwicklis, Edward M.; Gillies, Daniel C.

    1999-01-01

    Yucca Mountain, in southern Nevada, is being investigated by the U.S. Department of Energy as a potential site for a repository for high-level radioactive waste. This report documents the results of surface-based geologic, pneumatic, hydrologic, and geochemical studies conducted during 1992 to 1996 by the U.S. Geological Survey in the vicinity of the North Ramp of the Exploratory Studies Facility (ESF) that are pertinent to understanding multiphase fluid flow within the deep unsaturated zone. Detailed stratigraphic and structural characteristics of the study area provided the hydrogeologic framework for these investigations. Multiple lines of evidence indicate that gas flow and liquid flow within the welded tuffs of the unsaturated zone occur primarily through fractures. Fracture densities are highest in the Tiva Canyon welded (TCw) and Topopah Spring welded (TSw) hydrogeologic units. Although fracture density is much lower in the intervening nonwelded and bedded tuffs of the Paintbrush nonwelded hydrogeologic unit (PTn), pneumatic and aqueous-phase isotopic evidence indicates that substantial secondary permeability is present locally in the PTn, especially in the vicinity of faults. Borehole air-injection tests indicate that bulk air-permeability ranges from 3.5x10-14 to 5.4x10-11 square meters for the welded tuffs and from 1.2x10-13 to 3.0x10-12 square meters for the non welded and bedded tuffs of the PTn. Analyses of in-situ pneumatic-pressure data from monitored boreholes produced estimates of bulk permeability that were comparable to those determined from the air-injection tests. In many cases, both sets of estimates are two to three orders of magnitude larger than estimates based on laboratory analyses of unfractured core samples. The in-situ pneumatic-pressure records also indicate that the unsaturated-zone pneumatic system consists of four subsystems that coincide with the four major hydrogeologic units of the unsaturated zone at Yucca Mountain. In descending order, these hydrogeologic units are the Tiva Canyon welded (TCw), Paintbrush nonwelded (PTn), Topopah Spring welded (TSw ), and Calico Hills nonwelded (CHn). Deep percolation takes place as episodic pulses of inflow that propagate rapidly to depth and apparently bypass most of the rock matrix. Field-scale and core-scale water potentials throughout much of the PTn and TSw are very high, generally greater than -0.3 megapascals, and are nearly depth invariant. Thus, the imbibition capacity of the densely welded tuffs, at least near fractures, is very small because of low matrix permeabilities and low water-potential gradients across the fracture-matrix interface. The combination of high fracture permeability, high water potentials, high matrix saturations, and low matrix permeabilities results in a percolation environment that favors deep fracture flow. The episodic pulses of inflow are evidenced in the sporadic but nevertheless commonplace occurrence of water with concentrations of radioactive isotopes indicative of origins postdating the atmospheric testing of nuclear weapons. High concentrations of tritium have been detected at many horizons within the PTn and in the top of the TSw. Much lower concentrations of tritium, indicating the mixing of a bomb-pulse component with older water, have been detected in the deeper sections of the TSw and in the CHn. Evidence for fracture flow also is apparent in the widespread occurrence of perched water with chemical and isotopic signatures that indicate a fracture-flow origin for at least some of this water. In the North Ramp area, perched water has been detected at the base of the Topopah Spring Tuff or in the top of the underlying non welded to partially welded tuffs of the Calico Hills Formation in every dry-drilled borehole of sufficient depth to penetrate the Topopah Spring Tuff-Calico Hills Formation contact. The concentrations of the major ions of the perched water are similar to that of TSw pore water at borehole UZ-14, CHn pore water, and saturated-zone water at boreholes NRG-7 a and SD-9. The absolute chlorid

  16. Transient hydrogeologic models for submarine flow in volcanic seamounts: 2. Comparison of the Hawaiian, Canary, and Marquesas Islands

    Microsoft Academic Search

    L. B. Christiansen; G. Garven

    2004-01-01

    Large bathymetric gradients associated with volcanic seamounts can drive convective flow, while thick sedimentary aprons that typically surround volcanic edifices host compaction-driven flow. In these submarine environments the interactions of compaction-driven and buoyancy-driven fluid flow lead to complex hydrogeologic regimes. We apply transient numerical models of coupled fluid flow and heat transport to the Hawaiian, Canary, and Marquesas Islands to

  17. A Comparison of Hydrogeologic Models, Tritium/helium-3, and Deliberate Tracer Experiments to Understand Ground Water Residence Time

    NASA Astrophysics Data System (ADS)

    McDermott, J.; Clark, J.; Avisar, D.; Hudson, G.

    2005-12-01

    Assessment of subsurface residence time of ground water, used for determining flow paths and travel times, is an important criterion for understanding and monitoring water quality and in situ biogeochemical reactions. Established methods of determining travel time include hydrogeologic modeling, transient tracers and deliberate tracers. This paper presents a comparison of these three methods near the Montebello Forebay recharge site in Los Angeles County, California. Sulfur hexafluoride (SF6) gas tracer was injected into the Rio Hondo and San Gabriel recharge basins in early 2003. During this two-year experiment, SF6 was detected at nine monitoring wells, indicating that SF6 was successfully transferred from surface water to groundwater during percolation at spreading basins. SF6 tracer was detected at 11 of the 18 production wells sampled during this study, indicating travel time for recharge water to some of the wells is less than two years. All tritium/3He ages are greater than 10 years for the production wells, indicating mixing of young and old ground water. Because tritium/3He ages do not mix linearly - the mixed age is weighted by each flow path's initial tritium content - this technique leads to over-estimation of ground water age. At four of the eleven wells with SF6 detections, the hydrogeologic travel times determined in a previous study by Bookman-Edmonston Engineering were less than 10 weeks and are in basic agreement with the SF6 travel times determined in the present study. However, at the other seven wells, estimated hydrogeologic travel times were greater than 200 weeks, significantly longer than indicated by the tracer data. Leakage through low permeability layers leading to earlier tracer arrival provides a likely explanation. At all wells with no detected tracer, the hydrogeologic times were greater than three years.

  18. Hydrogeological settings of a volcanic island (San Cristóbal, Galapagos) from joint interpretation of airborne electromagnetics and geomorphological observations

    NASA Astrophysics Data System (ADS)

    Pryet, A.; d'Ozouville, N.; Violette, S.; Deffontaines, B.; Auken, E.

    2012-08-01

    Many volcanic islands face freshwater stress and the situation may worsen with climate change and sea level rise. In this context, an optimum management of freshwater resources becomes crucial, but is often impeded by the lack of data. With the aim of investigating the hydrogeological settings of Southern San Cristóbal Island (Galapagos), we conducted an helicopter-borne, transient electromagnetic survey with the SkyTEM system. It provided unprecedented insights in the 3-D resistivity structure of this extinct basaltic shield. Combined with remote sensing and fieldwork, it allowed the definition of the first hydrogeological conceptual model of the island. Springs are fed by a series of perched aquifers overlying a regional basal aquifer subject to seawater intrusion. Dykes, evidenced by alignments of eruptive cones at the surface, correspond to sharp sub-vertical contrasts in resistivity in the subsurface, and impound groundwater in a summit channel. Combined with geomorphological observations, airborne electromagnetics is shown to be a useful tool for hydrogeological exploratory studies in complex, poorly known environments. It allows optimal development of land-based geophysical surveys and drilling campaigns.

  19. Hydrogeological settings of a volcanic island (San Cristóbal, Galapagos) from joint interpretation of airborne electromagnetics and geomorphological observations

    NASA Astrophysics Data System (ADS)

    Pryet, A.; d'Ozouville, N.; Violette, S.; Deffontaines, B.; Auken, E.

    2012-12-01

    Many volcanic islands face freshwater stress and the situation may worsen with climate change and sea level rise. In this context, an optimum management of freshwater resources becomes crucial, but is often impeded by the lack of data. With the aim of investigating the hydrogeological settings of southern San Cristóbal Island (Galapagos), we conducted a helicopter-borne, transient electromagnetic survey with the SkyTEM system. It provided unprecedented insights into the 3-D resistivity structure of this extinct basaltic shield. Combined with remote sensing and fieldwork, it allowed the definition of the first hydrogeological conceptual model of the island. Springs are fed by a series of perched aquifers overlying a regional basal aquifer subject to seawater intrusion. Dykes, evidenced by alignments of eruptive cones at the surface, correspond to sharp sub-vertical contrasts in resistivity in the subsurface, and impound groundwater in a summit channel. Combined with geomorphological observations, airborne electromagnetics are shown to be a useful for hydrogeological exploratory studies in complex, poorly known environments. They allow optimal development of land-based geophysical surveys and drilling campaigns.

  20. Geophysical borehole logging for control of driller's records: hydrogeological case study from Voltaian sedimentary rocks in northern Ghana

    NASA Astrophysics Data System (ADS)

    Agyekum, William; Klitten, Kurt; Armah, Thomas; Banoeng-Yakubo, Bruce; Amartey, Edmund Okoe

    2013-06-01

    The low borehole yielding potential and the high drilling failure rate of the Voltaian sedimentary rocks of Northern Ghana have been of concern to many local hydrogeologists and international donors. Consequently, several donor-supported projects have been instituted within the last few years with the view to study the hydrogeological characteristics of this `difficult' rock system. One such project is the geophysical borehole logging of 13 boreholes drilled into the Voltaian sedimentary rocks of Northern Ghana to enhance detailed hydrogeological assessment. Natural gamma detectors embedded in the five exploratory logging tools employed for the study ensured depth control by comparing their individual gamma log signatures. The combined gamma and formation resistivity/conductivity response logs provided more detailed lithological information than were shown in the driller's/geologist's logs. Significant discrepancies between the logging results and the reported drilled depths, construction depths, and screen settings were observed in seven of the thirteen investigated boreholes. Thus, the reliability of driller's borehole records seems questionable, which will hamper hydrogeological studies and the mapping of groundwater resources. Further, it may be supposed that the productivity of most wells in Ghana is compromised by poor depth control of screen placement.

  1. 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.

  2. 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.

  3. Comparative study of methods of preparing hydraulic-head surfaces and the introduction of automated hydrogeological-GIS techniques

    NASA Astrophysics Data System (ADS)

    Salama, Ramsis B.; Ye, Lin; Broun, Jacqueline

    1996-11-01

    Construction of hydraulic-head surface (HHS) maps is the most commonly used technique for groundwater evaluation. A review of methods used for constructing HHS maps showed that, of the manual methods, the hydrogeological interpretative technique produces a better surface than the equally spaced approach. Geostatistical methods gave similar surfaces to the manual methods; they share the problem of groundwater contours intersecting surface contours and the inability to identify groundwater discharge areas. The results showed that the automated hydrogeological-GIS (geographical information system) techniques, which take into account the hydrogeomorphic and topographic controls, produced the most realistic surfaces. Groundwater contours follow the hydrogeomorphic trends, do not intersect surface contours and can properly identify areas of groundwater discharge. The major advantage of the hydrogeological-GIS technique is the ability to prepare HHS maps with a small number of data points. It is also possible to use regressions from other catchments to prepare HHS maps for catchments with similar hydrogeomorphic characteristics and elevation ranges but which have no data.

  4. 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.

  5. Hydrogeologic controls on groundwater recharge and salinization: a geochemical analysis of the northern Hueco Bolson aquifer, Texas, USA

    NASA Astrophysics Data System (ADS)

    Druhan, Jennifer L.; Hogan, James F.; Eastoe, Christopher J.; Hibbs, Barry J.; Hutchison, William R.

    2008-03-01

    Identification of hydrogeologic controls on groundwater flowpaths, recharge, and salinization is often critical to the management of limited arid groundwater resources. One approach to identifying these mechanisms is a combined analysis of hydrogeologic and hydrochemical data to develop a comprehensive conceptual model of a groundwater basin. To demonstrate this technique, water samples were collected from 33 discrete vertical zone test holes in the Hueco Bolson aquifer, located within the Trans-Pecos Texas region and the primary water resource for El Paso, Texas, USA and Juárez, Mexico. These samples were analyzed for a suite of geochemical tracers and the data evaluated in light of basin hydrogeology. On the basis of ?2H and ?18O data, two regional recharge sources were recognized, one originating from western mountain-fronts and one from through-flow of the adjacent Tularosa aquifer. Chloride concentrations were strongly correlated with lithologic formations and both Cl/Br and 36Cl ratios suggested the primary chloride source is halite dissolution within a specific lithologic unit. In contrast, sulfur isotopes indicated that most sulfate originates from Tularosa basin Permian gypsum sources. These results yielded a more comprehensive conceptual model of the basin, which suggested that chloride salinization of wells is the result of upconing of waters from the Fort Hancock formation.

  6. 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.

  7. Hydrogeological application of electrical resistivity tomography: Implementing a fixed-electrode strategy

    NASA Astrophysics Data System (ADS)

    Pezeshkpour, Parsa

    The requirements of environmental assessments and of understanding and monitoring in-situ mass and heat processes in porous media have led to the development of geophysical methods for remote mapping and monitoring of contaminant plumes and fluid migration. With the possible exception of seismic approaches, electrical methods known as Electrical Resistivity Tomography (ERT) have become the most widely studied and used for these purposes. Wherever a sufficient contrast in ground resistivity is generated by human or natural processes, monitoring the resistivity structure over time may give insight into these processes. ERT has monitoring applications in processes such as Enhanced Oil Recovery (EOR), Slurry Fracture Injection (SFI), and monitoring transport processes in hydrogeology. A permanent electrode arrangement for long term monitoring removes the effects of Earth's heterogeneity and anisotropy when a process is analyzed as a function of time. As a starting point on the work described in this thesis, ERT data were collected from a Cambridge, Ontario, sand pit before, immediately after and one week following a 11000 liters slurry injection. These measurements verified that ERT could detect changes caused by the injection and later movement of this conductive mixture in the ground. The commercial equipment used for these measurements was not well suited to the tasks, mainly because it was extremely slow. Further, there was a lack of robust and user-friendly three-dimensional modeling software to use as a means of predicting response and---eventually---as the engine of an inversion routine. Finally, it was difficult to analyze the injection situation in terms of how best to place a limited number of surface and borehole electrodes to most effectively monitor the injection fluids. The remainder of the thesis addresses these problems. The first objective was to design and construct a more suitable ERT measurement system. The second objective was to adapt SALTFLOW as a platform for both the resistivity and hydrogeological modeling of the saline groundwater flow resulting from waste injection. The third objective was to develop methods of sensitivity analysis that will allow a more efficient examination of the electrode arrays that could be effectively used in a given situation. The fourth objective was to demonstrate the ERT method and the improvements undertaken by the author on the data collected at the Cambridge injection site. The thesis has not, in fact, met all these objectives, but has made substantial progress towards them. The complete design of the measurement system and the construction of its potential measurement components were achieved. A lack of capacity in the science shops, however, resulted in the power (current) supply not being constructed in time for field evaluation of the injection or its aftermath. (Abstract shortened by UMI.)

  8. The flood event of November 2013 in Calabria (southern Italy): damage and hydrogeological characteristics

    NASA Astrophysics Data System (ADS)

    Petrucci, Olga; Caloiero, Tommaso; Aurora Pasqua, Angela

    2014-05-01

    On November 19th, 2013, Calabria region (southern Italy) has been affected by a flood event which caused numerous damages in particular in the Ionian side of the region. In this work, the event is analyzed in terms of damage and hydrologic features. Beside rainfall, the event has been characterized by intense sea storms which, increased by Sirocco gusts, obstructed the outlet of the floods toward the sea. As a result, river overflowing was amplified and caused the breaking of either natural or artificial embankments. Damage affected 49 municipalities located in the mid-east sector, on a surface of 1898 km2 (12.6% of the Calabrian area). Roads (damaged in 86% of the affected municipalities) and private buildings (39%) were the most heavily damaged elements: in many cases the water level reached 1m. People were directly involved in risky situations but they managed to save their lives: only two people were injured. Return periods of daily rain can be classified as ordinary (between 2 and 13 years) with the only exception of a gauge located in the northern east sector, which showed a return period of more than 100 years. On the contrary, 3-hour rain shows peak values of 160 mm and return period higher than 200 years. As a result, the event can be considered an "impulsive" one, powered by intense hourly rain, and its dangerousness was mainly related to the "flash" character of the triggered floods. The analysis of circumstances in which people were directly threatened confirms floods as the main source of risk, both indoors (65% of cases) and outdoors (35%); in the latter case, the majority of people involved were on board of vehicles (26%). Differently from the past Calabrian damaging hydrogeological events, people did not adopt unnecessary risky behaviors, and in 26% of cases they managed to save their life without any help. Probably this is the factor that lead to low damage to people, since only two people were slightly injured. These results could be proficiently used in information and awareness campaigns for people on self-protective behavior to be used during damaging hydrogeological events.

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

    USGS Publications Warehouse

    Oki, D.S.; Souza, W.R.; Bolke, E.L.; Bauer, G.R.

    1998-01-01

    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. Ground-water flow is: (a) predominantly upward in the low-permeability sedimentary units; and (b) predominantly horizontal in the high-permeability sedimentary units.

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

    USGS Publications Warehouse

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

    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.

  11. Geophysical Evidence for Lithologic and Hydrogeological Controls on Vegetation Communities in a Large Northern Peatland

    NASA Astrophysics Data System (ADS)

    Slater, L. D.; Reeve, A.; Utne, I. J.; Comas, X.; Ulrich, C. A.

    2002-12-01

    Recent conceptual models invoke hydrogeologic processes as a controlling factor in the development of the striking vegetation patterns observed in northern peatlands. These processes regulate the supply of solutes to the peat surface, controlling the surface-water chemistry and the supply of nutrients to plants. Geophysical studies in Caribou Bog, a 2200-hectare peatland in central Maine, indicate a close correlation between lithology of the underlying mineral soil and dominant vegetation. Electrical resistivity imaging along a 1 km transect across the central unit of Caribou Bog resolves underlying glaciomarine clay thickness. Ground penetrating radar precisely defines the glaciomarine interface where peat thickness is less than 10 m. Direct verification of peatland thickness and sampling at the mineral soil contact constrains the geophysical interpretation. Wooded heath interspersed with sphagnum/leatherleaf lawn occurs where glaciomarine clay accumulation is thickest (estimated to exceed 10 m in parts). Abrupt thinning of the glaciomarine clay, such that peat rests directly on bedrock in parts, correlates with a sharp transition to shrub heath dominated vegetation. The location of open pools within the wooded heath of Caribou Bog coincides with localized thinning of the glaciomarine clay and exposure of bedrock at the base of the bog. Groundwater flow cells recorded over two years suggest that the glaciomarine clay acts as a confining layer and impacts nutrient supply from the mineral soil, and hence vegetation patterns, at the bog surface.

  12. 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).

  13. 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.

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

    NASA Astrophysics Data System (ADS)

    Revil, A.; Karaoulis, M.; Johnson, T.; Kemna, A.

    2012-06-01

    Low-frequency geoelectrical methods include mainly self-potential, resistivity, and induced polarization techniques, which have potential in many 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 redox-active 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.

  15. Deriving hydrogeological parameters through time series analysis of groundwater head fluctuations around well fields

    NASA Astrophysics Data System (ADS)

    Obergfell, Christophe; Bakker, Mark; Zaadnoordijk, Willem Jan; Maas, Kees

    2013-08-01

    A method is presented by which time series analysis is applied to support groundwater system conceptualization and provide calibration targets for a steady groundwater model. The method is demonstrated for heads measured in the vicinity of a drinking-water well field. The estimated steady response to pumping was used to classify the monitoring wells as semi-confined or phreatic. Based on this conceptualization, the aquifer system was represented by two layers separated by a leaky bed, which represents the resistance to vertical flow of the layers. The model could be calibrated satisfactorily using the drawdowns estimated by time series analysis. This approach was more successful than deriving the aquifer parameters directly from the analytical well function of Hantush, which was successful for a limited number of monitoring wells only and required the a priori choice of the elevation of a confining layer which was not clear from bore logs. This study shows that time series analysis can lead to qualitative and quantitative insights regarding the local hydrogeology, providing complementary information to available bore logs to design a conceptual groundwater model. Time series analysis provides a cost-effective alternative to pumping tests when measured head fluctuations influenced by pumping wells are available.

  16. 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

  17. 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.

  18. Water balance in the Guarani Aquifer outcrop zone based on hydrogeologic monitoring

    NASA Astrophysics Data System (ADS)

    Wendland, E.; Barreto, C.; Gomes, L. H.

    2007-09-01

    SummaryMain objective of this work was the study of the infiltration and recharge mechanisms in the Guarani Aquifer System (GAS) outcrop zone. The study was based on hydrogeologic monitoring, evapotranspiration and water balance in a pilot watershed. The pilot watershed (Ribeirão da Onça) is situated in the outcrop zone of the Guarani Aquifer between parallels 22°10' and 22°15' (south latitude) and meridians 47°55' and 48°00' (west longitude). For the execution of the research project, a monitoring network (wells, rain gauge and linigraph) was installed in the watershed. Data have been systematically collected during the period of a hydrological year. Water level fluctuation has been used to estimate deep recharge and subsurface storage variation. The method used to estimate the direct recharge adopted the hypothesis that the recession of the groundwater level obeys a function of power law type. Direct recharge is obtained through the difference between the actual level of an unconfined aquifer and the level indicated by extrapolation of the recession curve, in a given period. Base outflow is estimated through a mixed function (linear and exponential). Outflow in the creek has been measured with current meter and monitored continuously with a linigraph. The annual infiltration in 2005 was estimated to be 350 mm, while the deep recharge, based on water balance, appears to be 3.5% of the precipitation (1410 mm). These results indicate that the estimated long term water availability of the Guarani Aquifer System should be studied more carefully.

  19. Modeling of nitrogen cycle and nitrate transfer in regional hydrogeologic systems

    SciTech Connect

    Geng, Q.Z. [Ecole Nationale Superieure des Mines de Pairs, Fontainebleau (France). Centre d`Informatique Geologique]|[Sinotech Engineering Consultants, Inc., Taipei (Taiwan, Province of China). Geotechnical Dept.; Girard, G.; Ledoux, E. [Ecole Nationale Superieure des Mines de Paris, Fontainebleau (France). Centre d`Informatique Geologique

    1996-03-01

    A model of the nitrogen cycle and nitrate leaching in soil, called MORELN, was developed to calculate the nitrate flux percolating from soils into aquifers. It uses a ``coupled model,`` which simulates both surface and subsurface flows. A third model, NEWSAM, is linked to the above models to simulate nitrate migration in an aquifer system. This methodology gives a quantitative global description of nitrate transfer, taking into account both leaching in soils and migration in aquifers. Three examples of application tested this methodology (especially the nitrate leaching code, MORELN) at different scales and with different emphases: (1) in a soil plot of several square meters; (2) in a small experimental basin of several square kilometers; and (3) in a regional hydrogeologic system of several hundred square kilometers. Satisfactory results were obtained for the simulation of nitrate leaching at the small scale. Major differences between the measured and simulated nitrate concentrations were observed in a regional aquifer, where the measured concentration does not spatially correlate and the larger spatial variability of the input data were averaged in the model.

  20. Impact of hydrogeological data on measures of uncertainty, site characterization and environmental performance metrics

    NASA Astrophysics Data System (ADS)

    de Barros, Felipe P. J.; Ezzedine, Souheil; Rubin, Yoram

    2012-02-01

    The significance of conditioning predictions of environmental performance metrics (EPMs) on hydrogeological data in heterogeneous porous media is addressed. Conditioning EPMs on available data reduces uncertainty and increases the reliability of model predictions. We present a rational and concise approach to investigate the impact of conditioning EPMs on data as a function of the location of the environmentally sensitive target receptor, data types and spacing between measurements. We illustrate how the concept of comparative information yield curves introduced in de Barros et al. [de Barros FPJ, Rubin Y, Maxwell R. The concept of comparative information yield curves and its application to risk-based site characterization. Water Resour Res 2009;45:W06401. doi:10.1029/2008WR007324] could be used to assess site characterization needs as a function of flow and transport dimensionality and EPMs. For a given EPM, we show how alternative uncertainty reduction metrics yield distinct gains of information from a variety of sampling schemes. Our results show that uncertainty reduction is EPM dependent (e.g., travel times) and does not necessarily indicate uncertainty reduction in an alternative EPM (e.g., human health risk). The results show how the position of the environmental target, flow dimensionality and the choice of the uncertainty reduction metric can be used to assist in field sampling campaigns.

  1. 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.

  2. 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).

  3. Selected hydrogeologic and water-quality data from Jones Beach Island, Long Island, New York

    USGS Publications Warehouse

    Scorca, M.P.; Reilly, T.E.; Franke, O.L.

    1995-01-01

    A data-collection site was instrumented on Jones Beach Island, a barrier island south of Long Island, N.Y., to study local freshwater/ saltwater relations in the shallow ground-water system. A geologic test boring revealed about 88 feet of well-sorted glacial outwash sand above about 15 feet of Gardiners Clay, which directly overlies silty sand of the Magothy Formation. Tidal effects on water levels in Great South Bay, the upper glacial aquifer, and the Magothy aquifer were observed and quantified with a tidal gage in the bay and analog water-level recorders in the wells.Chloride concentrations in the upper Magothy aquifer were higher than expected--about 270 mg/L (milligrams per liter), and those in the upper glacial aquifer were 17,000 to 19,000 mg/L, about the same as in Great South Bay. Estimates of pressure and freshwater equivalent heads indicate that, at the data-collection site, freshwater is discharging upward from the Magothy aquifer into the salty upper glacial aquifer, but dilution by this freshwater is undetectable. The reason for the elevated chloride concentration in the Magothy aquifer cannot be determined from available hydrogeologic information.

  4. 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.

  5. Hydrogeology and chemical quality of water and soil at Carroll Island, Aberdeen Proving Ground, Maryland

    USGS Publications Warehouse

    Tenbus, F.J.; Phillips, S.W.

    1996-01-01

    Carroll Island was used for open-air testing of chemical warfare agents from the late 1940's until 1971. Testing and disposal activities weresuspected of causing environmental contamination at 16 sites on the island. The hydrogeology and chemical quality of ground water, surface water, and soil at these sites were investigated with borehole logs, environmental samples, water-level measurements, and hydrologic tests. A surficial aquifer, upper confining unit, and upper confined aquifer were defined. Ground water in the surficial aquifer generally flows from the east-central part of the island toward the surface-water bodies, butgradient reversals caused by evapotranspiration can occur during dry seasons. In the confined aquifer, hydraulic gradients are low, and hydraulic head is affected by tidal loading and by seasonal pumpage from the west. Inorganic chemistry in the aquifers is affected by brackish-water intrusion from gradient reversals and by dissolution ofcarboniferous shell material in the confining unit.The concentrations of most inorganic constituents probably resulted from natural processes, but some concentrations exceeded Federal water-quality regulations and criteria. Organic compounds were detected in water and soil samples at maximum concentrations of 138 micrograms per liter (thiodiglycol in surface water) and 12 micrograms per gram (octadecanoic acid in soil).Concentrations of organic compounds in ground water exceeded Federal drinking-water regulations at two sites. The organic compounds that weredetected in environmental samples were variously attributed to natural processes, laboratory or field- sampling contamination, fallout from industrial air pollution, and historical military activities.

  6. Hydrogeologic Effects on Design and Results for Multiple Midwest Regional Carbon Sequestration Partnership Test Sites

    NASA Astrophysics Data System (ADS)

    Sminchak, J.; Kelley, M.; Gerst, J.; Meggyesy, D.

    2008-12-01

    In planning and monitoring CO2 injection experiments at Midwest Regional Carbon Sequestration Partnership sites, it was found that the hydrogeologic framework had a significant influence on the test design and results. The test sites are located along major regional geologic structures in the Midwestern United States: the Appalachian Basin, the Cincinnati Arch, and the Michigan Basin. Factors such as injection target thickness, permeability, formation pressures, and injection depths had a significant impact on the tests. In the Appalachian Basin, the nature of the injection targets resulted in a flexible injection plan capable of testing the injectivity of multiple targets. At the Cincinnati Arch site, approximately 90 m section of Mt. Simon Sandstone is present with promising hydraulic properties. As such, this test was focused on examining the mobility of the CO2 within the storage formation, since a supply of CO2 may not be available to test maximum injection rates. At the Michigan Basin site, a large supply of CO2 was available. This test involved a longer injection period and more detailed examination of the CO2 distribution in the deep rock formations. In addition, it allowed more analysis of the hydraulic pressure response in the reservoir. This work was done as part of the Midwest Regional Carbon Sequestration Partnership (MRCSP); DOE/NETL Cooperative Agreement No. DE-FC26-05NT42589.

  7. 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.

  8. 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.

  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. An integrated model for simulating nitrogen trading in an agricultural catchment with complex hydrogeology.

    PubMed

    Cox, T J; Rutherford, J C; Kerr, S C; Smeaton, D C; Palliser, C C

    2013-09-30

    Nitrogen loads to several New Zealand lakes are dominated by nonpoint runoff from pastoral farmland which adversely affects lake water quality. A 'cap and trade' scheme is being considered to help meet targets set for nitrogen loads to Lake Rotorua, and a numerical model, NTRADER, has been developed to simulate and compare alternative schemes. NTRADER models both the geophysics of nitrogen generation and transport, including groundwater lag times, and the economics of 'cap and trade' schemes. It integrates the output from several existing models, including a farm-scale nitrogen leaching and abatement model, a farm-scale management economic model, and a catchment-scale nitrogen transport model. This paper details modeling methods and compares possible trading program design features for the Lake Rotorua catchment. Model simulations demonstrate how a cap and trade program could be used to effectively achieve challenging environmental goals in the targeted catchment. However, results also show that, due to complex hydrogeology, satisfactory environmental outcomes may be not achieved unless groundwater lag times are incorporated into the regulatory scheme. One way to do this, as demonstrated here, would be to explicitly include lag times in the cap and trade program. The utility of the model is further demonstrated by quantifying relative differences in abatement costs across potential regulatory schemes. PMID:23771202

  11. 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.

  12. 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

  13. 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.

  14. Hydrogeologic factors that influence ground water movement in the desert southwest United States

    USGS Publications Warehouse

    Chuang, Frank C.; McKee, Edwin H.; Howard, Keith A.

    2003-01-01

    A project to study ground-water and surface-water interactions in the desert southwestern United States was initiated in 2001 by the Tucson, Arizona office of the Water Resources Division, U.S. Geological Survey (USGS). One of the goals of the Southwest Ground-water Resources Project was to develop a regional synthesis that includes the use of available digital geologic data, which is growing rapidly due to the increasing use of Geographic Information Systems (GIS). Included in this report are the digital maps and databases of geologic information that should have a direct impact on the studies of ground-water flow and surface-water interaction. Ground-water flow is governed by many geologic factors or elements including rock and soil permeability, stratigraphy and structural features. These elements directly influence ground-water flow, which is key to understanding the possible inter-connectivity of aquifer systems in desert basins of the southwestern United States. We derive these elements from the evaluation of regional geology and localized studies of hydrogeologic basins. These elements can then be applied to other unstudied areas throughout the desert southwest. This report presents a regional perspective of the geologic elements controlling ground-water systems in the desert southwest that may eventually lead to greater focus on smaller sub-regions and ultimately, to individual ground-water basins.

  15. Hydrogeology and groundwater flow in a basalt-capped Mesozoic sedimentary series of the Ethiopian highlands

    NASA Astrophysics Data System (ADS)

    Vandecasteele, Ine; Nyssen, Jan; Clymans, Wim; Moeyersons, Jan; Martens, Kristine; van Camp, Marc; Gebreyohannes, Tesfamichael; Desmedt, Florimond; Deckers, Jozef; Walraevens, Kristine

    2011-05-01

    A hydrogeological study was undertaken in the Zenako-Argaka catchment, near Hagere Selam in Tigray, northern Ethiopia, during the rainy season of 2006. A geological map was produced through geophysical measurements and field observations, and a fracture zone identified in the north west of the catchment. A perched water table was found within the Trap Basalt series above the laterized upper Aram Aradam Sandstones. A map of this water table was compiled. Water-level variation during the measurement period was at least 4.5 m. Variation in basal flow for the whole catchment for the measurement period was between 12 and 276 m3/day. A groundwater flow model was produced using Visual MODFLOW, indicating the general direction of flow to be towards the south, and illustrating that the waterways have only a limited influence on groundwater flow. The soil water budget was calculated for the period 1995-2006, which showed the important influence of the distribution of rainfall in time. Although Hagere Selam received some 724 mm of rainfall per year over this period, the strong seasonal variation in rainfall meant there was a water deficit for on average 10 months per year.

  16. Hydrogeological definition and applicability of abandoned coal mines as water reservoirs.

    PubMed

    Ordóñez, A; Jardón, S; Álvarez, R; Andrés, C; Pendás, F

    2012-08-01

    Hydrogeologically, the Central Coal Basin (Asturias, Spain) is characterized by predominantly low-permeability materials that make up a multilayer aquifer with very low porosity and permeability values, where the sandstones act as limited aquifers, and wackes, mudstones, shales and coal seams act as confining levels. Preferential groundwater flow paths are open fractures and zones of decompression associated with them, so the hydraulic behaviour of the system is more associated with fracturing than lithology. Thus, abandoned and flooded mines in the area acquire an important role in the management of water resources, setting up an artificial "pseudo-karst" aquifer. This paper evaluates the potential application of the abandoned mines as underground reservoirs, both for water supply and energetic use, mainly through heat pumps and small hydropower plants. In particular, the groundwater reservoir shaped by the connected shafts Barredo and Figaredo has been chosen, and a detailed and multifaceted study has been undertaken in the area. The exposed applications fit with an integrated management of water resources and contribute to improve economic and social conditions of a traditional mining area in gradual decline due to the cessation of such activity. PMID:22833009

  17. 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. [St. Petersburg Mining Inst. (Russian Federation); Pozdniakov, S.P.; Shestakov, V.M. [Moscow State Univ. (Russian Federation); Roshal, A.A. [Geosoft-Eastlink, Moscow (Russian Federation)

    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.

  18. Topographic stress perturbations in southern Davis Mountains, west Texas 2. Hydrogeologic implications

    USGS Publications Warehouse

    Morin, R.H.; Savage, W.Z.

    2002-01-01

    As part of a regional groundwater investigation, geophysical logs were obtained in two municipal water wells located near the west Texas city of Alpine. These boreholes are 252 and 285 m deep and penetrate extrusive rocks of Tertiary age. The deeper well was drilled in the central valley and the other along the northern flank of an east-west trending valley-ridge setting. Analysis and interpretation of the logs reveal that the two wells are subjected to significantly different stress environments because of topographic effects and exhibit significantly different hydrogeologic properties. Water production is associated with two specific types of features common to both wells: (1) the upper and lower contacts of a dense trachyte unit located in the shallow part of the wells and (2) deeper zones of highly fractured rocks within the interior of a basalt formation. The transmissivity of the trachyte boundaries is twice as large in the central valley well as it is in the ridge flank well, whereas the transmissivity of the deeper basalts is an order of magnitude greater in the flank well than it is in the central well. This discrepancy is examined from the perspective of rock failure, fracture opening, and flow enhancement by computing values for a Drucker-Prager stability factor that is based on the magnitudes of the normal and deviatoric stress invariants as a function of depth. Thus the field measurements and subsequent stress analysis offer evidence of a coupled tectonic-hydrologic interaction at this site.

  19. 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.

  20. 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.

  1. 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.

  2. Evaluation of intrinsic groundwater vulnerability to pollution: COP method for pilot area of Carrara hydrogeological system (Northern Tuscany, Italy)

    NASA Astrophysics Data System (ADS)

    Baldi, B.; Guastaldi, E.; Rossetto, R.

    2009-04-01

    During the characterization of the Apuan Alps groundwater body ( "Corpo Idrico Sotterraneo Significativo", briefly CISS) (Regione Toscana, 2007) the intrinsic vulnerability has been evaluated for Carrara hydrogeological system (Northern Tuscany, Italy) by means of COP method, developed within COST 620 European Action (Zwalhlen, 2003). This system is both characterized by large data availability and it is considered an highly risky zone since groundwater protection problems (turbidity of the tapped spring waters and hydrocarbons contamination) and anthropic activity (marble quarries). The study area, 20 Km2large, has high relief energy, with elevations ranging from 5 to 1700 m amsl in almost 5 km. Runoff is scarce except during heavy rainfall; due to the presence of carbonate rocks infiltration is high: groundwater discharge at 155-255 m amsl. The area is located in the north-western part of Apuan Alps Metamorphic Complex, characterized by carbonate and non-carbonate rocks belonging to the non-metamorphic Tuscan Units (Carnic-Oligocene), Mesozoic Succession, Middle-Triassic Succession, and metamorphic Paleozoic rocks. The main geological structure of the area is the Carrara Syncline, constituted prevalently by dolostones, marbles and cherty limestones. These carbonate formations define several moderately to highly productive hydrogeological units, characterized by fissured and karst flow. Hydrogeological system may be subdivided in two different subsets, because of both geo-structural set up and area conformation. However, these are hydrogeologically connected since anisotropy and fractures of karst groundwater. The southern boundary of Carrara hydrogeological system shows important dammed springs, defined by low productive units of Massa Unit (Cambriano?-Carnic). COP methodology for evaluating intrinsic vulnerability of karst groundwater is based on three main factors for the definition of vulnerability itself: COPIndex = C (flow Concentration) *O (Overlying layers) *P (Precipitation). In this way it is possible to estimate the natural grade of groundwater protection (O factor), determined by both soils properties and vadose zone lithology, and then evaluate how this protection could be modified by infiltration processes (diffused or concentrated, C factor) and climatic conditions (P factor). Factor elaborations have been calculated by study area discretization by means of raster grid with square cells, 100 m large, yielding the values distribution of sub-factor for each factor, and then the spatial distribution of intrinsic vulnerability, as result of geoprocessing and map analysis raster techniques in software ESRI ArcInfo® 9.1. Results shows in the study area: 1) Medium and high values of vulnerability classes; 2) Areas with high vulnerability located in zones with low O protection index and moderate protection reduction; 3) C factor contributes to the high vulnerability where superficial cover supports more the infiltration than the run-off (slope between 8 and 31%); 4) Low vulnerability grade areas are either inside unproductive hydrogeological units, or with thick superficial covers. Comparing these results with previous study, the distribution obtained by COP methodology shows larger variations between very high and high vulnerability area distribution. Most of the first areas are located in the central part of hydrogeological system, near to the main spring, and also in northern areas, where there is a swallow hole. This result yields a more precautionary scenario for particularly sensitive are characterized by high anthropogenic activity (marble quarry). Moreover, the vulnerability of such area is confirmed by both natural tracers (Lycopodium clavatum; Baldi, 2004) and environmental isotopes (2H, 3H, 18O; Doveri, 2005). This methodology allowed adding further information about intrinsic vulnerability of a hydrological contest very sensitive to anthropogenic pressures, and it is important for water resource as well. Such vulnerability map highlights higher vulnerability areas than those showed in previ

  3. MODFLOW-2000, the U.S. Geological Survey Modular Ground-Water Model -Documentation of the Hydrogeologic-Unit Flow (HUF) Package

    USGS Publications Warehouse

    Anderman, E.R.; Hill, M.C.

    2000-01-01

    This report documents the Hydrogeologic-Unit Flow (HUF) Package for the groundwater modeling computer program MODFLOW-2000. The HUF Package is an alternative internal flow package that allows the vertical geometry of the system hydrogeology to be defined explicitly within the model using hydrogeologic units that can be different than the definition of the model layers. The HUF Package works with all the processes of MODFLOW-2000. For the Ground-Water Flow Process, the HUF Package calculates effective hydraulic properties for the model layers based on the hydraulic properties of the hydrogeologic units, which are defined by the user using parameters. The hydraulic properties are used to calculate the conductance coefficients and other terms needed to solve the ground-water flow equation. The sensitivity of the model to the parameters defined within the HUF Package input file can be calculated using the Sensitivity Process, using observations defined with the Observation Process. Optimal values of the parameters can be estimated by using the Parameter-Estimation Process. The HUF Package is nearly identical to the Layer-Property Flow (LPF) Package, the major difference being the definition of the vertical geometry of the system hydrogeology. Use of the HUF Package is illustrated in two test cases, which also serve to verify the performance of the package by showing that the Parameter-Estimation Process produces the true parameter values when exact observations are used.

  4. 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.

  5. 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.

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

    USGS Publications Warehouse

    Smith, Barry S.; Harlow, George E.

    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.

  7. Mineral water discharges at the Azores archipelago (Portugal): hydrogeological setting, chemical composition and mapping

    NASA Astrophysics Data System (ADS)

    Freire, P.; Cruz, J.; Coutinho, R.; Costa, A.; Antunes, P.

    2009-04-01

    The geological setting of the Azores archipelago, located in the North Atlantic ocean, about 1500 km form Portugal mainland and made of 9 islands of volcanic origin, enhances the multiplicity of surface hydrothermal manifestations. Therefore, a field survey made possible to identify 101 mineral water discharges in the Azores, mainly of CO2-rich cold waters and thermal waters, spread along São Miguel (75%), Terceira (6%), Graciosa (7%), Pico (2%), Faial (3%), São Jorge (5%) and Flores ( 2%) islands, as well as fumarolic grounds. Furnas and Fogo central volcanoes, two of the three composite active volcanoes that dominates the geology of São Miguel, the largest island of the archipelago, represent respectively about 41% and 24% of the discharges from the Azores. Discharges are mainly from fissured aquifers, made of basaltic or trachitic lava flows. Instead, discharges from porous aquifers, made of pyroclastic deposits, mainly of pumice type, are less common, and are more frequent at São Miguel island. The studied discharges correspond mainly to springs (75), and also to boiling pools (10), at fumarolic grounds, 14 drilled wells and 2 large-diameter wells. The boiling pools are only observable at São Miguel island, while drilled wells were made at São Miguel, Terceira and Graciosa. Groundwater at Azores occurs in two major aquifers systems: (1) the basal aquifer system, which corresponds to fresh-water lenses floating on underlying salt water, and (2) in perched-water bodies. The basal aquifer system is in the coastal area, presenting generally a very low hydraulic gradient. From the 14 drilled wells only two are in perched-water bodies. Considering mineral springs, the majority discharge from perched-water bodies (77%), while all the boiling pools also discharge in altitude, also from perched -water bodies. During the field survey an extensive campaign of sample collection was made in all islands, in order to characterize the chemical composition of these waters, which presents a large range of water types and mineralization magnitude. Several groups of waters are defined: (1) Na-HCO3 and Na-HCO3-Cl type waters, to which almost all the thermal and CO2-rich waters belong, (2) Na-Cl type waters, to which discharges from the basal aquifer system belong and (3) acid-SO4 type waters, to which some of the boiling waters of São Miguel island belong. A few samples show intermediate facies between these main water types. The pH range between 2.2 and 7.82, discharge temperature between 15°C and 99.5°C (median=35°C), and conductivity varies between 139 and 43100 S/cm (median=906 S/cm). The main hydrogeochemical processes are the CO2-dominated volatile absorption, water-rock interaction and mixture with hydrothermal fluids. Sulfate dominated composition is explained by the influence of steam heating, and the Na-Cl water type result from mixture with sea salts. For the purpose of mapping mineral water discharges at the Azores a geochemical atlas was made using ESRI ArcGis 9.1 software. Data was divided in classes according to quartile values and spatial analysis was made through thematic mapping, for several features, as hydrogeological setting, water types and variables as discharge temperature, pH, conductivity, free CO2 and major elements content. In the present contribution several examples of the hydrogeological maps are shown.

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

    USGS Publications Warehouse

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

    2002-01-01

    The hydrogeology and water-quality characteristics of the Lower Floridan aquifer and the relation of the Lower Floridan aquifer to the framework of the Floridan aquifer system were evaluated during a 6-year (1995-2001) study. The study area, a 7,500 square-mile area of east-central Florida, is underlain by three principal hydrogeologic units: the surficial aquifer system, the intermediate confining unit, and the Floridan aquifer system. The Floridan aquifer system, a carbonate-rock aquifer system composed of the Upper Floridan aquifer, a middle semiconfining unit, a middle confining unit, and the Lower Floridan aquifer, is the major source of water supply to east-central Florida. The Upper Floridan aquifer provides much of the water required to meet the current (2002) demand; however, the Lower Floridan aquifer is being used increasingly as a source of freshwater, particularly for municipal needs. For this reason, a better understanding of the aquifer is needed. The Lower Floridan aquifer is present throughout east-central Florida. The aquifer is composed of alternating beds of limestone and dolomite, and is characterized by abundant fractured dolomite zones and solution cavities. The altitude of the top of the Lower Floridan aquifer ranges from less than 600 feet below sea level in the northern part of the study area to more than 1,600 feet below sea level in the southwestern part. Thickness of the unit ranges from about 910 to 1,180 feet. The top of the Lower Floridan aquifer generally is marked by an increase in formation resistivity and by an increase in the occurrence of fractures and solution cavities within the carbonates. Also, a noticeable increase in borehole flow often marks the top of the unit. The bottom of the Lower Floridan aquifer is based on the first occurrence of evaporites. Ground-water in the Lower Floridan aquifer generally moves in a southwest-to-northeast direction across the study area. In September 1998, the altitude of the potentiometric surface of the Lower Floridan aquifer ranged from about 16 to 113 feet above sea level, and altitudes in May 1999 were about 2 to 7 feet lower than those measured in September 1998. The potentiometric surface of the Floridan aquifer system is constantly fluctuating, mainly in response to seasonal variations in rainfall and ground-water withdrawals. Seasonal fluctuations in the Lower Floridan aquifer typically range from about 2 to 10 feet. Water samples from 50 Lower Floridan aquifer wells were collected during this study. Most samples were analyzed in the field for temperature, pH, and specific conductance, and in the laboratory for major cations and anions. Specific conductance ranged from 147 to 6,710 microsiemens per centimeter. Chloride concentrations ranged from 3.0 to 2,188 milligrams per liter; sulfate concentrations ranged from 0.2 to 750 milli-grams per liter; and hardness ranged from 69 to 940 milligrams per liter. Water was least mineralized in the recharge areas of the Lower Floridan aquifer in the western part of the study area. The most mineralized water in the Lower Floridan aquifer occurred along parts of the Wekiva and St. Johns Rivers and in much of the eastern and southern parts of the study area. The altitude of the base of freshwater in the Floridan aquifer system (where chloride concentrations are equal to 250 milligrams per liter) is variable throughout the study area. The estimated position of the 250 milligram per liter isochlor surface is less than 200 feet below sea level in much of the eastern part of the study area, including the areas along the St. Johns River in Lake, Seminole, and Volusia Counties and near the Wekiva River in western Seminole County. The altitude of the 250 milligram per liter isochlor exceeds 3,000 feet below sea level in the extreme southwestern part of the study area.

  9. 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.

  10. Hydrogeologic characteristics of four public drinking-water supply springs in northern Arkansas

    USGS Publications Warehouse

    Galloway, Joel M.

    2004-01-01

    In October 2000, a study was undertaken by the U.S. Geological Survey (USGS) in cooperation with the Arkansas Department of Health to determine the hydrogeologic characteristics, including the extent of the recharge areas, for Hughes Spring, Stark Spring, Evening Shade Spring, and Roaring Spring, which are used for public-water supply in northern Arkansas. Information pertaining to each spring can be used to enable development of effective management plans to protect these water resources and public health. An integrated approach to determine the ground-water characteristics and the extent of the local recharge areas of the four springs incorporated tools and methods of hydrology, structural geology, geomorphology, geophysics, and geochemistry. Analyses of discharge, temperature, and water quality were completed to describe ground-water flow characteristics, source-water characteristics, and connectivity of the ground-water system with surface runoff. Water-level contour maps were constructed to determine ground-water flow directions and ground-water tracer tests were conducted to determine the extent of the recharge areas and ground-water flow velocities. Hughes Spring supplies water for the city of Marshall, Arkansas, and the surrounding area. The mean annual discharge for Hughes Spring was 2.9 and 5.2 cubic feet per second for water years 2001 and 2002, respectively. Recharge to the spring occurs mainly from the Boone Formation (Springfield Plateau aquifer). Ground-water tracer tests indicate the recharge area for Hughes Spring generally coincides with the surface drainage area (15.8 square miles) and that Hughes Spring is connected directly to the surface flow in Brush Creek. The geochemistry of Hughes Spring demonstrated variations with flow conditions and the influence of surface-runoff in the recharge area. Calcite saturation indices, total dissolved solids concentrations, and hardness demonstrate noticeable differences with flow conditions reflecting the reduced residence time and interaction of water with the source rock within the ground-water system at higher discharges for Hughes Spring. Concentrations of fecal indicator bacteria also demonstrated a substantial increase during high-flow conditions, suggesting that a non-point source of bacteria possibly from livestock may enter the system. Conversely, nutrient concentrations did not vary with flow and were similar to concentrations reported for undeveloped sites in the Springfield Plateau and Ozark aquifers in northern Arkansas and southern Missouri. Deuterium and oxygen-18 data show that the Hughes Spring discharge is representative of direct precipitation and not influenced by water enriched in oxygen-18 through evaporation. Discharge data show that Hughes Spring is dominated by conduit type ground-water flow, but a considerable component of diffuse flow also exists in the ground-water system. Carbon-13 data indicate a substantial component of the recharge water interacts with the surface material (soil and regolith) in the recharge area before entering the ground-water system for Hughes Spring. Tritium data for Hughes Spring indicate that the discharge water is a mixture of recent recharge and sub-modern water (recharged prior to 1952). Stark Spring supplies water for the city of Cushman, Arkansas, and the surrounding area. 2 Hydrogeologic Characteristics of Four Public Drinking-Water Supply Springs in Northern Arkansas The mean annual discharge for Stark Spring was 0.5 and 1.5 cubic feet per second for water years 2001 and 2002, respectively. The discharge and water-quality data show the ground-water system for Stark Spring is dominated by rapid recharge from surface runoff and mainly consists of a conduit- type flow system with little diffuse-type flow. Analyses of discharge data show that the estimated recharge area (0.79 square mile) is larger than the surface drainage area (0.34 square mile). Ground-water tracer tests and the outcrop of the

  11. Hydrogeologic Conditions at the DUSEL Mid-level Campus and Implications for Large Cavern Design

    NASA Astrophysics Data System (ADS)

    Weinig, W. T.; Popielak, R. S.; Stetler, L. D.

    2010-12-01

    In July 2007 the former Homestake gold mine in Lead, South Dakota was selected as the site of a new Deep Underground Science and Engineering Laboratory (DUSEL). The mid-level campus, including several new, large excavations, is planned for development at the 4850 Level of the facility (1,489 meters below surface datum) near the former location of the neutrino experiment conducted by Dr. Ray Davis starting in about 1965. The mid-level campus will host a wide range of scientific research to be conducted in an environment that minimizes the influence of cosmic radiation. While operating, Homestake was the deepest underground mine in North America, with workings reaching over 2,439 meters deep. In June 2003, mining had ceased and the dewatering pumps were turned off. The resultant flooding reached a level approximately 98 meters above the planned mid-level campus before dewatering pumps were turned back on in June 2008. In May 2009, water levels fell below the 4850 Level of the DUSEL facility allowing commencement of development work for the mid-level campus. Data collected prior to the cessation of mining indicated long-term average groundwater inflows of 1900 liters/minute (L/min) to 2600 L/min. For a mine with over 480 kilometers of workings, this represents a relatively small groundwater flux, consistent with reported hydraulic conductivities of 10-5 centimeters per second (cm/sec) to 10-7 cm/sec. Recent calculations based on analysis of dewatering data indicate a bulk hydraulic conductivity of 10-6 to 10-7 cm/sec. Data collected during a geotechnical investigation in 2009 indicated discharges from new boreholes in the area of the planned mid-level campus of less than 0.25 liters per minute. Shut-in pressures measured over relatively brief periods during the investigation ranged from zero to 4.1 megaPascals (MPa). Data collected during drilling and subsequent borehole televiewer logs showed relatively distributed inflows throughout the length of the boreholes. A conceptual hydrogeologic model for the mid-level campus including poorly connected fractures, medium to high pressures, and low flow rates was postulated based on the 2009 data combined with historical inflow and hydraulic conductivity measurements. Ongoing data collection in late 2009 and 2010 support this conceptual model. The conceptual hydrogeologic model indicates that inflows to the planned large excavations will be relatively low, although groundwater pressure approaching 14 MPa may be encountered. The drainage systems for the new excavations will primarily serve as pressure relief, with additional diffusion of potential high pressures and low groundwater fluxes provided by micro-fractured yield zones around the perimeters of the excavations. The drainage systems are not expected to handle large flow rates, consistent with the experience during Homestake operational days and conditions observed in the chamber that housed the Davis neutrino experiment for nearly 40 years.

  12. Differential Hydrogeological Effects of Draining Tunnels Through the Northern Apennines, Italy

    NASA Astrophysics Data System (ADS)

    Vincenzi, Valentina; Gargini, Alessandro; Goldscheider, Nico; Piccinini, Leonardo

    2014-05-01

    Water inflows are a major challenge in tunnelling and particularly difficult to predict in geological settings consisting of heterogeneous sedimentary rock formations with complex tectonic structure. For a high-speed railway line between Bologna and Florence (Italy), a series of seven railway tunnels was drilled through turbiditic formations, ranging from pelitic rocks with thin arenitic layers over sequences including thick-bedded sandstone to calcareous rocks showing chemical dissolution phenomena (karstification). The tunnels were built as draining tunnels and caused significant impacts, such as drying of springs and base-flow losses at mountain streams. A comprehensive hydrological monitoring programme and four multi-tracer test were done, focusing on four sections of the tunnel system. The tracer tests delivered unprecedented data on groundwater flow and transport in turbiditic aquifers and made it possible to better characterize the differential impacts of tunnel drainage along a geological gradient. The impact radius is 200 m in the thin-bedded sequences but reaches 2.3-4.0 km in calcareous and thick-bedded arenitic turbidites. Linear flow velocities, as determined from the peaks of the tracer breakthrough curves, range from 3.6 m/day in the thin-bedded turbidites to 39 m/day in the calcareous rocks (average values from the four test sites). At several places, discrete fault zones were identified as main hydraulic pathways between impacted streams and draining tunnels. This case shows that ignoring the hydrogeological conditions in construction projects can cause terrible damage, and the study presents an approach to better predict hydraulic impacts of draining tunnels in complex sedimentary rock settings.

  13. Progress Toward Understanding of Coupled Microbiology, Biogeochemistry, and Hydrogeology Controls on Subsurface Mobility of Uranium

    NASA Astrophysics Data System (ADS)

    Long, P. E.; Williams, K. H.; Davis, J. A.; Banfield, J. F.; Bargar, J.; Lovley, D. R.; Hatfield, K.; Wilkins, M. J.; Yabusaki, S.; Murray, C. J.; Jaffe, P. R.; Science Team, R.

    2011-12-01

    Uranium as an anthropogenic environmental contaminant stems from nuclear weapons production and the nuclear fuel cycle for nuclear power generation over the last 65 years. Progress in research, monitoring, and clean up at such sites has resulted in both long-term monitoring and field scale manipulation experimental data that are enabling in-depth understanding of coupling among microbiology, biogeochemistry, and hydrogeology subsurface processes controlling mobility of U. One such site, the U.S. Department of Energy's IFRC at Rifle, CO, has hosted several acetate electron donor amendment and non-biostimulated desorption tracer tests culminating in an experiment in 2010 in which bicarbonate promoted uranium desorption and acetate amendment were combined and compared to an acetate amendment-only experiment in the same experimental plot. Enzymatic U reduction rates were not impacted by the increased abundance of Ca-uranyl-carbonate aqueous complexes in the bicarbonate part of the experiment. However, the importance of changes in bicarbonate on U desorption is clear. Bicarbonate increases during acetate-only field experiments due to microbial activity promote U desorption and this must be accounted for in estimating field-scale reduction rates for U. The Rifle site also has more than a decade of monitoring data that show the plume is attenuating much slower than predicted. Naturally reduced zones at the site indicate that microbially-mediated natural reducing conditions have partially reduced U(VI) to U(IV) and this contributes to plume persistence. However, we are just beginning to explore the full range of biogeochemical processes that will enable us to more accurately predict plume attenuation and that will be needed to either enhance or decrease mobility of U as remedial strategies.

  14. Collaborative research: Hydrogeological-geophysical methods for subsurface site characterization. 1997 annual progress report

    SciTech Connect

    Rubin, Y.; Morrison, F.; Rector, J.

    1997-10-31

    'In the first year of the project progress has been made in several areas which are central to the project. Development of Joint Hydrogcological-Geophysical Co-Interpretation Procedure A strong effort was invested in developing the concepts and the algorithm of the joint hydrogeological-geophysical co-interpretation approach. The reason for the concerted effort in that direction is the large amount of time the authors expect this task will take before completion, and also by the need to direct the data collection efforts. They are currently testing several ideas for co-interpretation, but they are at a quite advanced stage. They are testing these ideas using synthetic studies as well as some preliminary data that has been collected at the Lawrence Livermore National Lab site. Part of the efforts is in developing methods for estimation of the semi-variograms of the logconductivity based on direct measurements as well as on seimsic velocity measurements as obtained from cross-well tomography. Preliminary tests show that these two sources of data complement each other quite well: the direct measurements supply the medium to small wave number portion of the logconductivity spectra, while a high resolution seismic survey supplies a good coverage of the large wave number part of the spectra. They advanced significantly with formulating their approach for using Ground Penetrating Radar (GPR) imaging techniques in shallow subsurface surveys. Synthetic surveys show that GPR maybe very suitable for mapping spatial variations in saturations. They have access to field data and are analyzing it. Some additional issues that were investigated are also listed.'

  15. 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.

  16. Hydrogeological and isotopic study of surface water and groundwater in the Eastern Haouz Plain. Western Morocco

    NASA Astrophysics Data System (ADS)

    El Mandour, Abdennabi; Rochdane, Samia; Reddy, Venkat; Himi, Mahjoub; Casas, Albert

    2014-05-01

    The Eastern Haouz area, characterized by a semi-arid climate, is part of the Haouz plain. The basin is built over a broad synclinal between the High Atlas and the Jebilets mountains. The compilation of geological, geophysical and hydrogeological data shows that this area is straddling two major basins of western Morocco. Map of the river system and the piezometric map show the same division line of surface water and groundwater. This division line oriented NNW-SSE is evidenced by the rise of the basement constituted by Paleozoic schists that outcrop near Tamelalt. Thus we can distinguish two main directions of groundwater flow feeding two watersheds (Tensift and Oum Rabiaa rivers) and two large reservoirs in the region of Marrakech. As a contribution to solve the water supply problem in the area, a hydrochemical study has been conducted, involving 40 groundwater samples for major ions and 20 stable isotope analyses. Hydrochemical results show the geological control on water quality. Samples from Paleozoic schists and Triassic sediments are relatively highly mineralisation and unsuitable for drinking as well as for irrigation. Conversely, groundwater from the alluvial plains is relatively less mineralised than other older geological formations; however, many of the samples are also non-potable. Apart of salinity problem, about 25% of the samples have higher nitrate content than the drinking water permissible limit. Stable isotope analysis show that groundwater recharge to the phreatic aquifer is controlled by local conditions. The small difference in the isotopic content of river water and a group of groundwater samples is interpreted as the evaporation effect during the recharge. On the other hand, the group of samples with relatively depleted stable isotopic content shows faster recharge conditions and less water-rock interaction. Finally, another group of samples is relatively enriched in stable isotope content and confirm an increase during the recharge processes and higher soil-water interaction. This may be partially due to return flow from agricultural irrigation.

  17. 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)

  18. Transport and fate of nitrate and pesticides: hydrogeology and riparian zone processes.

    PubMed

    Puckett, Larry J; Hughes, W Brian

    2005-01-01

    There is continuing concern over potential impacts of widespread application of nutrients and pesticides on ground- and surface-water quality. Transport and fate of nitrate and pesticides were investigated in a shallow aquifer and adjacent stream, Cow Castle Creek, in Orangeburg County, South Carolina. Pesticide and pesticide degradate concentrations were detected in ground water with greatest frequency and largest concentrations directly beneath and downgradient from the corn (Zea mays L.) field where they were applied. In almost all samples in which they were detected, concentrations of pesticide degradates greatly exceeded those of parent compounds, and were still present in ground waters that were recharged during the previous 18 yr. The absence of both parent and degradate compounds in samples collected from deeper in the aquifer suggests that this persistence is limited or that the ground water had recharged before use of the pesticide. Concentrations of NO(-)(3) in ground water decreased with increasing depth and age, but denitrification was not a dominant controlling factor. Hydrologic and chemical data indicated that ground water discharges to the creek and chemical exchange takes place within the upper 0.7 m of the streambed. Ground water had its greatest influence on surface-water chemistry during low-flow periods, causing a decrease in concentrations of Cl(-), NO(-)(3), pesticides, and pesticide degradates. Conversely, shallow subsurface drainage dominates stream chemistry during high-flow periods, increasing stream concentrations of Cl(-), NO(-)(3), pesticides, and pesticide degradates. These results point out the importance of understanding the hydrogeologic setting when investigating transport and fate of contaminants in ground water and surface water. PMID:16275729

  19. 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.

  20. 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.

  1. A hydrogeologic framework for characterizing summer streamflow sensitivity to climate warming in the Pacific Northwest, USA

    NASA Astrophysics Data System (ADS)

    Safeeq, M.; Grant, G. E.; Lewis, S. L.; Kramer, M. G.; Staab, B.

    2014-09-01

    Summer streamflows in the Pacific Northwest are largely derived from melting snow and groundwater discharge. As the climate warms, diminishing snowpack and earlier snowmelt will cause reductions in summer streamflow. Most regional-scale assessments of climate change impacts on streamflow use downscaled temperature and precipitation projections from general circulation models (GCMs) coupled with large-scale hydrologic models. Here we develop and apply an analytical hydrogeologic framework for characterizing summer streamflow sensitivity to a change in the timing and magnitude of recharge in a spatially explicit fashion. In particular, we incorporate the role of deep groundwater, which large-scale hydrologic models generally fail to capture, into streamflow sensitivity assessments. We validate our analytical streamflow sensitivities against two empirical measures of sensitivity derived using historical observations of temperature, precipitation, and streamflow from 217 watersheds. In general, empirically and analytically derived streamflow sensitivity values correspond. Although the selected watersheds cover a range of hydrologic regimes (e.g., rain-dominated, mixture of rain and snow, and snow-dominated), sensitivity validation was primarily driven by the snow-dominated watersheds, which are subjected to a wider range of change in recharge timing and magnitude as a result of increased temperature. Overall, two patterns emerge from this analysis: first, areas with high streamflow sensitivity also have higher summer streamflows as compared to low-sensitivity areas. Second, the level of sensitivity and spatial extent of highly sensitive areas diminishes over time as the summer progresses. Results of this analysis point to a robust, practical, and scalable approach that can help assess risk at the landscape scale, complement the downscaling approach, be applied to any climate scenario of interest, and provide a framework to assist land and water managers in adapting to an uncertain and potentially challenging future.

  2. 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.

  3. 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.

  4. Characterization of a Gas Station Site Contaminated with Fuel Hydrocarbons using Geophysical and Hydrogeological Investigations

    NASA Astrophysics Data System (ADS)

    Kim, C.; Ko, K.; Kim, J.; Park, S.; Son, J.; Jeong, J.; Cho, S.

    2005-12-01

    The geophysical and hydrogeological investigations were conducted to characterize a former gas station site contaminated with gasoline and diesel hydrocarbons. The free product of petroleum hydrocarbons, LNAPL, was identified in the downgradient monitoring wells at the site, and also found in the seepage adjacent to the small stream, located approximately 50 meters downstream of the gas station in the southwest direction. To locate buries USTs and fuel lines, GPR (Ground Penetrating Radar) survey was performed at the site. The results of GPR survey showed the presence of buried the seven USTs including one unknown UST and two fuel lines. The electrical resistivity and additional GPR surveys were also conducted to map water table and to characterize shallow geologic structures over the inclined area covered with grass and plants. The investigation results showed that the shallow geologic structure includes: (1) upper soil unit of high resistivity values, mostly rock fragments with sand, (2) lower soil unit of low resistivity values, residual soils weathered from the bedrock which play a role as major groundwater path, and (3) bedrock, granite, of high resistivty values. These geophysical results well matched the sediment core logging. The results also show that the water table elevation varies with topography from approximately 1.5 to 3 meters below the ground surface. It is, therefore, believed that the free product leaked from the USTs and/or fuel lines at the station has transported downgradient over the water table beneath the inclined area and encountered the small stream located southwest of the station, and that most of petroleum-impacted zone lies within the residual, weathered soil near the water table in the area. The study results also show that the geophysical methods can be a very useful tool for characterization of the contamination sites.

  5. 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

  6. Providing a Connection between a Bayesian Inverse Modeling Tool and a Coupled Hydrogeological Processes Modeling Software

    NASA Astrophysics Data System (ADS)

    Frystacky, H.; Osorio-Murillo, C. A.; Over, M. W.; Kalbacher, T.; Gunnell, D.; Kolditz, O.; Ames, D.; Rubin, Y.

    2013-12-01

    The Method of Anchored Distributions (MAD) is a Bayesian technique for characterizing the uncertainty in geostatistical model parameters. Open-source software has been developed in a modular framework such that this technique can be applied to any forward model software via a driver. This presentation is about the driver that has been developed for OpenGeoSys (OGS), open-source software that can simulate many hydrogeological processes, including couple processes. MAD allows the use of multiple data types for conditioning the spatially random fields and assessing model parameter likelihood. For example, if simulating flow and mass transport, the inversion target variable could be hydraulic conductivity and the inversion data types could be head, concentration, or both. The driver detects from the OGS files which processes and variables are being used in a given project and allows MAD to prompt the user to choose those that are to be modeled or to be treated deterministically. In this way, any combination of processes allowed by OGS can have MAD applied. As for the software, there are two versions, each with its own OGS driver. A Windows desktop version is available as a graphical user interface and is ideal for the learning and teaching environment. High-throughput computing can even be achieved with this version via HTCondor if large projects want to be pursued in a computer lab. In addition to this desktop application, a Linux version is available equipped with MPI such that it can be run in parallel on a computer cluster. All releases can be downloaded from the MAD Codeplex site given below.

  7. 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.

  8. Combining Airbone geophysics and hydrogeologic modeling to determine the hydrologic boundary condition below the sea.

    NASA Astrophysics Data System (ADS)

    Schaars, Frans; Viezzoli, Andrea; Rolf, Harry; Groen, Michel; Auken, Esben; Bjergsted Pedersen, Jesper

    2013-04-01

    Groundwater models in coastal aquifers are often used to predict the effect of hydrological changes (climate change, sea level rise, and etcetera) on groundwater heads and seawater intrusion. The results can be very sensitive to the boundary condition that is used for the coastal edge of the model, even when the main interest is in groundwater heads only. This is especially the case when models are calibrated, because groundwater heads from monitoring wells are often the only calibration data available. The lack of offshore data is a complicating factor that consequently decreases the reliability of the entire model. Using Airborne electromagnetic geophysics (e.g., SkyTEM) we can determine the extent of the fresh groundwater wedge below the sea. However, the low resistive seawater and subsequent geo-electrical equivalence makes it difficult to determine the thickness and resistivity of the resistive zone. Furthermore, it can be impossible to separate lithology and water-quality based on the resistivity model only, for example in concurrent presence of clays and saline aquifers. In this study we combined the resistivity model and the hydrological model in a number of cross sections perpendicular to the coast. We use data from the SKYTEM survey that was done in 2011 along the coast at the dune area of PWN water supply. Additionally we have continuous vertical electrical sounding (CVES) profiles and electrical cone penetration (CPT) tests on the beach. We will show the benefits of combining both hydrogeological modeling and airborne geophysical measurements to determine a good boundary condition and the matching lithology and water quality. We will also determine the effect of commonly used boundary conditions that were derived without the geophysical information. Comparing these results we demonstrate the benefit of the combination and give practical recommendations for future applications.

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

    NASA Astrophysics Data System (ADS)

    Sugarman, Peter J.; Miller, Kenneth G.

    1997-02-01

    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 Kw0 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.

  10. Hydrogeology and water quality of the North Canadian River alluvium, Concho Reserve, Canadian County, Oklahoma

    USGS Publications Warehouse

    Becker, C.J.

    1998-01-01

    A growing user population within the Concho Reserve in Canadian County, Oklahoma, has increased the need for drinking water. The North Canadian River alluvium is a reliable source of ground water for agriculture, industry, and cities in Canadian County and is the only ground-water source capable of meeting large demands. This study was undertaken to collect and analyze data to describe the hydrogeology and ground-water quality of the North Canadian River alluvium within the Concho Reserve. The alluvium forms a band about 2 miles long and 0.5 mile wide along the southern edge of the Concho Reserve. Thickness of the alluvium ranges from 19 to 75 feet thick and averages about 45 feet in the study area. Well cuttings and natural gamma-ray logs indicate the alluvium consists of interfingering lenses of clay, silt, and sand. The increase of coarse-grained sand and the decrease of clay and silt with depth suggests that the water-bearing properties of the aquifer within the study area improve with depth. A clay layer in the upper part of the aquifer may be partially responsible for surface water ponding in low areas after above normal precipitation and may delay the infiltration of potentially contaminated water from land surface. Specific conductance measurements indicate the ground-water quality improves in a northern direction towards the terrace. Water-quality properties, bacteria counts, major ion and nutrient concentrations, trace-element and radionuclide concentrations, and organic compound concentrations were measured in one ground-water sample at the southern edge of the Concho Reserve and comply with the primary drinking-water standards. Measured concentrations of iron, manganese, sulfate, and total dissolved solids exceed the secondary maximum contaminant levels set for drinking water. The ground water is a calcium sulfate bicarbonate type and is considered very hard, with a hardness of 570 milligrams per liter as calcium carbonate.

  11. 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.

  12. Hydrogeological framework and water balance studies in parts of Krishni Yamuna interstream area, Western Uttar Pradesh, India

    NASA Astrophysics Data System (ADS)

    Ahmed, Izrar; Umar, Rashid

    2008-02-01

    The Krishni Yamuna interstream area is a micro-watershed in the Central Ganga Plain and a highly fertile track of Western Uttar Pradesh. The Sugarcane and wheat are the major crops of the area. Aquifers of Quaternary age form the major source of Irrigation and municipal water supplies. A detailed hydrogeological investigation was carried out in the study area with an objective to assess aquifer framework, groundwater quality and its resource potential. The hydrogeological cross section reveals occurrence of alternate layers of clay and sand. Aquifer broadly behaves as a single bodied aquifer down to the depth of 100 m bgl (metre below ground level) as the clay layers laterally pinch out. The depth to water in the area varies between 5 and 16.5 m bgl. The general groundwater flow direction is from NE to SW with few local variations. An attempt has been made to evaluate groundwater resources of the area. The water budget method focuses on the various components contributing to groundwater flow and groundwater storage changes. Changes in ground water storage can be attributed to rainfall recharge, irrigation return flow and ground water inflow to the basin minus baseflow (ground water discharge to streams or springs), evapotranspiration from ground water, pumping and ground water outflow from the basin. The recharge is obtained in the study area using Water table fluctuation and Tritium methods. The results of water balance study show that the total recharge in to the interstream region is of the order of 185.25 million m3 and discharge from the study area is of the order of 203.24 million m3, leaving a deficit balance of -17.99 million m3. Therefore, the present status of groundwater development in the present study area has acquired the declining trend. Thus, the hydrogeological analysis and water balance studies shows that the groundwater development has attained a critical state in the region.

  13. 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.

  14. Selected hydrogeologic data for the southwest Glendive Preliminary Logical Mining Unit and adjacent areas, Dawson County, Montana

    USGS Publications Warehouse

    Roberts, R.S.

    1987-01-01

    Hydrogeologic data were collected from a coal area in Dawson County, Montana, to provide a basis for identifying and characterizing the groundwater resources. Inventory records for 72 domestic, stock, irrigation, unused, and observation wells are tabulated in the report; the data were collected principally from 1977 through 1981. The location of each well is shown on a map. Natural-gamma geophysical logs, and water level measurements are also included for selection wells. Twenty-six analyses of groundwater identify the chemical-constituent concentrations and physical properties of water from sampled wells. (USGS)

  15. Hydrogeologic, soil, and water-quality data for j-field, Aberdeen Proving Ground, Maryland, 1989-94

    USGS Publications Warehouse

    Phelan, D.J.

    1996-01-01

    Disposal of chemical-warfare agents, munitions, and industrial chemicals in J-Field, Aberdeen Proving Ground, Maryland, has resulted in ground-water, surface-water, and soil contamination. This report presents data collected by the U.S. Geological Survey from Novembr 1989 through September 1994 as part of a remedial investigation of J-Field in response to the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA). Hydrogeologic data, soil-gas and soil-quality data, and water-qualtiy data are included.

  16. 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.

  17. Large-Scale Transport Model Uncertainty and Sensitivity Analysis: Distributed Sources in Complex Hydrogeologic Systems

    SciTech Connect

    Sig Drellack, Lance Prothro

    2007-12-01

    The Underground Test Area (UGTA) Project of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office is in the process of assessing and developing regulatory decision options based on modeling predictions of contaminant transport from underground testing of nuclear weapons at the Nevada Test Site (NTS). The UGTA Project is attempting to develop an effective modeling strategy that addresses and quantifies multiple components of uncertainty including natural variability, parameter uncertainty, conceptual/model uncertainty, and decision uncertainty in translating model results into regulatory requirements. The modeling task presents multiple unique challenges to the hydrological sciences as a result of the complex fractured and faulted hydrostratigraphy, the distributed locations of sources, the suite of reactive and non-reactive radionuclides, and uncertainty in conceptual models. Characterization of the hydrogeologic system is difficult and expensive because of deep groundwater in the arid desert setting and the large spatial setting of the NTS. Therefore, conceptual model uncertainty is partially addressed through the development of multiple alternative conceptual models of the hydrostratigraphic framework and multiple alternative models of recharge and discharge. Uncertainty in boundary conditions is assessed through development of alternative groundwater fluxes through multiple simulations using the regional groundwater flow model. Calibration of alternative models to heads and measured or inferred fluxes has not proven to provide clear measures of model quality. Therefore, model screening by comparison to independently-derived natural geochemical mixing targets through cluster analysis has also been invoked to evaluate differences between alternative conceptual models. Advancing multiple alternative flow models, sensitivity of transport predictions to parameter uncertainty is assessed through Monte Carlo simulations. The simulations are challenged by the distributed sources in each of the Corrective Action Units, by complex mass transfer processes, and by the size and complexity of the field-scale flow models. An efficient methodology utilizing particle tracking results and convolution integrals provides in situ concentrations appropriate for Monte Carlo analysis. Uncertainty in source releases and transport parameters including effective porosity, fracture apertures and spacing, matrix diffusion coefficients, sorption coefficients, and colloid load and mobility are considered. With the distributions of input uncertainties and output plume volumes, global analysis methods including stepwise regression, contingency table analysis, and classification tree analysis are used to develop sensitivity rankings of parameter uncertainties for each model considered, thus assisting a variety of decisions.

  18. 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.

  19. 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.

  20. 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.

  1. Hydrogeology and Simulated Ground-Water Flow in the Salt Pond Region of Southern Rhode Island

    USGS Publications Warehouse

    Masterson, John P.; Sorenson, Jason R.; Stone, Janet R.; Moran, S. Bradley; Hougham, Andrea

    2007-01-01

    The Salt Pond region of southern Rhode Island extends from Westerly to Narragansett Bay and forms the natural boundary between the Atlantic Ocean and the shallow, highly permeable freshwater aquifer of the South Coastal Basin. Large inputs of fresh ground water coupled with the low flushing rates to the open ocean make the salt ponds particularly susceptible to eutrophication and bacterial contamination. Ground-water discharge to the salt ponds is an important though poorly quantified source of contaminants, such as dissolved nutrients. A ground-water-flow model was developed and used to delineate the watersheds to the salt ponds, including the areas that contribute ground water directly to the ponds and the areas that contribute ground water to streams that flow into ponds. The model also was used to calculate ground-water fluxes to these coastal areas for long-term average conditions. As part of the modeling analysis, adjustments were made to model input parameters to assess potential uncertainties in model-calculated watershed delineations and in ground-water discharge to the salt ponds. The results of the simulations indicate that flow to the salt ponds is affected primarily by the ease with which water is transmitted through a glacial moraine deposit near the regional ground-water divide, and by the specified recharge rate used in the model simulations. The distribution of the total freshwater flow between direct ground-water discharge and ground-water-derived surface-water (streamflow) discharge to the salt ponds is affected primarily by simulated stream characteristics, including the streambed-aquifer connection and the stream stage. The simulated position of the ground-water divide and, therefore, the model-calculated watershed delineations for the salt ponds, were affected only by changes in the transmissivity of the glacial moraine. Selected changes in other simulated hydraulic parameters had substantial effects on total freshwater discharge and the distribution of direct ground-water discharge and ground-water-derived surface-water (streamflow) discharge to the salt ponds, but still provided a reasonable match to the hydrologic data available for model calibration. To reduce the uncertainty in predictions of watershed areas and ground-water discharge to the salt ponds, additional hydrogeologic data would be required to constrain the model input parameters that have the greatest effect on the simulation results.

  2. 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.

  3. Coupling of hydrogeological models with hydrogeophysical data to characterize seawater intrusion and shallow geothermal systems

    NASA Astrophysics Data System (ADS)

    Beaujean, J.; Kemna, A.; Engesgaard, P. K.; Hermans, T.; Vandenbohede, A.; Nguyen, F.

    2013-12-01

    While coastal aquifers are being stressed due to climate changes and excessive groundwater withdrawals require characterizing efficiently seawater intrusion (SWI) dynamics, production of geothermal energy is increasingly being used to hinder global warming. To study these issues, we need both robust measuring technologies and reliable predictions based on numerical models. SWI models are currently calibrated using borehole observations. Similarly, geothermal models depend mainly on the temperature field at few locations. Electrical resistivity tomography (ERT) can be used to improve these models given its high sensitivity to TDS and temperature and its relatively high lateral resolution. Inherent geophysical limitations, such as the resolution loss, can affect the overall quality of the ERT images and also prevent the correct recovery of the desired hydrochemical property. We present an uncoupled and coupled hydrogeophysical inversion to calibrate SWI and thermohydrogeologic models using ERT. In the SWI models, we demonstrate with two synthetic benchmarks (homogeneous and heterogeneous coastal aquifers) the ability of cumulative sensitivity-filtered ERT images using surface-only data to recover the hydraulic conductivity. Filtering of ERT-derived data at depth, where resolution is poorer, and the model errors make the dispersivity more difficult to estimate. In the coupled approach, we showed that parameter estimation is significantly improved because regularization bias is replaced by forward modeling only. Our efforts are currently focusing on applying the uncoupled/coupled approaches on a real life case study using field data from the site of Almeria, SE Spain. In the thermohydrogeologic models, the most sensitive hydrologic parameters responsible for heat transport are estimated from surface ERT-derived temperatures and ERT resistance data. A real life geothermal experiment that took place on the Campus De Sterre of Ghent University, Belgium and a synthetic case are tested. They consist in a thermal injection and storage of water in a shallow sandy aquifer. The use of a physically-based constraint accounting for the difference in conductivity between the formation and the tap injected water and based on the hydrogeological model calibrated first on temperatures is necessary to improve the parameter estimation. Results suggest that time-lapse ERT data may be limited but useful information for estimating groundwater flow and transport parameters for both the convection and conduction phases.

  4. 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.

  5. Groundwater geochemistry of the Yucatan Peninsula, Mexico: Constraints on stratigraphy and hydrogeology

    NASA Astrophysics Data System (ADS)

    Perry, Eugene; Paytan, Adina; Pedersen, Bianca; Velazquez-Oliman, Guadalupe

    2009-03-01

    SummaryWe report 87Sr/ 86Sr and ion concentrations of sulfate, chloride, and strontium in the groundwater of the northern and central Yucatan Peninsula, Mexico. Correlation between these data indicates that ejecta from the 65.95 m.y. old Chicxulub impact crater have an important effect on hydrogeology, geomorphology, and soil development of the region. Ejecta are present at relatively shallow subsurface depths in north-central Yucatan and at the surface along the Rio Hondo escarpment in southeast Quintana Roo, where they are referred to as the Albion Formation. Anhydrite/gypsum (and by inference celestite) are common in impact ejecta clasts and in beds and cements of overlying Paleocene and Lower Eocene rocks cored around the margin of the crater. The sulfate-rich minerals that are found in rocks immediately overlying the impact ejecta blanket, may either be partially mobilized from the ejecta layer itself or may have been deposited after the K/T impact event in an extensive pre-Oligocene shallow sea. These deposits form a distinctive sedimentary package that can be easily traced by the Eocene-Cretaceous 87Sr/ 86Sr signal. A distinct Sr isotopic signature and high SO 4/Cl ratios are observed in groundwater of northwestern and north-central Yucatan that interacts with these rocks. Moreover, the distribution of the gypsum-rich stratigraphic unit provides a solution-enhanced subsurface drainage pathway for a broad region characterized by dissolution features (poljes) extending from Chetumal, Quintana Roo to Campeche, Campeche. The presence of gypsum quarries in the area is also consistent with a sulfate-rich stratigraphic "package" that includes ejecta. The distinctive chemistry of groundwater that has been in contact with evaporite/ejecta can be used to trace flow directions and confirms a groundwater divide in the northern Peninsula. Information about groundwater flow directions and about deep subsurface zones of high permeability is useful for groundwater and liquid waste management in the area. Where it discharges at the coast, the unique chemistry of the groundwater that has interacted with the evaporite/ejecta strata may also have significant geomorphologic implications. While groundwater-seawater mixing at the coast has been shown to dissolve and erode limestone, PHREEQC modeling shows that mixing of water nearly saturated in CaSO 4 with seawater has a less vigorous dissolution effect due to its high Ca content.

  6. Fate and identification of oil-brine contamination in different hydrogeologic settings

    USGS Publications Warehouse

    Whittemore, D.O.

    2007-01-01

    Past disposal of oil-field brine at the surface has caused substantial contamination of water resources in Kansas. Natural saline water occurs in and discharges from Permian bedrock in parts of the state, and other anthropogenic sources of saline water exist, requiring clear identification of different sources. Time-series analysis of Cl- concentration and streamflow relative to pre-contamination contents, and end-member mixing plots, especially for Br- and Cl-, are practical methods for source differentiation and quantification. Although regulations preventing escape of saltwater from oil wells were first passed in Kansas in 1935, much oil and gas brine was disposed on the surface through the 1940s. Hydrogeologic characteristics of the areas with past surface disposal of oil brine differ appreciably and result in large differences in the ratio of saltwater transported in streams or ground water. Much of the brine disposed during the 1910s to 1940s in an area of silty clay soils overlying shale and limestone bedrock in south-central Kansas soon ran off or was flushed from the surface by rain into streams. Chloride concentration in the rivers draining this area often exceeded 1000 mg/L after the start of oil production up to the 1950s. Chloride content in the rivers then generally declined to about 100 mg/L or less in recent low flows. Oil brine was also disposed in surface ponds overlying the unconsolidated High Plains aquifer in south-central Kansas from the latter 1920s into the 1940s. Most of the surface-disposed brine infiltrated to the underlying aquifer. Where the High Plains aquifer is thin, saltwater has migrated along the top of clay layers or the underlying shaly bedrock and either discharged into small streams or flowed into thicker parts of the aquifer. Where the aquifer is thick, surface-disposed oil brine moved downward until reaching clay lenses, migrated latterly to the edge of the clay, and again moved downward if still dense enough. Water-level declines from pumping have increased the lateral migration rate of the saltwater contamination in the aquifer towards water-supply wells. The period of flushing most of the surface-disposed saltwater from the area of shale and limestone bedrock is on the order of many decades but is at least many centuries for the deeper parts of the High Plains aquifer. ?? 2007 Elsevier Ltd. All rights reserved.

  7. Large-Scale Transport Model Uncertainty and Sensitivity Analysis: Distributed Sources in Complex, Hydrogeologic Systems

    NASA Astrophysics Data System (ADS)

    Wolfsberg, A.; Kang, Q.; Li, C.; Ruskauff, G.; Bhark, E.; Freeman, E.; Prothro, L.; Drellack, S.

    2007-12-01

    The Underground Test Area (UGTA) Project of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office is in the process of assessing and developing regulatory decision options based on modeling predictions of contaminant transport from underground testing of nuclear weapons at the Nevada Test Site (NTS). The UGTA Project is attempting to develop an effective modeling strategy that addresses and quantifies multiple components of uncertainty including natural variability, parameter uncertainty, conceptual/model uncertainty, and decision uncertainty in translating model results into regulatory requirements. The modeling task presents multiple unique challenges to the hydrological sciences as a result of the complex fractured and faulted hydrostratigraphy, the distributed locations of sources, the suite of reactive and non-reactive radionuclides, and uncertainty in conceptual models. Characterization of the hydrogeologic system is difficult and expensive because of deep groundwater in the arid desert setting and the large spatial setting of the NTS. Therefore, conceptual model uncertainty is partially addressed through the development of multiple alternative conceptual models of the hydrostratigraphic framework and multiple alternative models of recharge and discharge. Uncertainty in boundary conditions is assessed through development of alternative groundwater fluxes through multiple simulations using the regional groundwater flow model. Calibration of alternative models to heads and measured or inferred fluxes has not proven to provide clear measures of model quality. Therefore, model screening by comparison to independently-derived natural geochemical mixing targets through cluster analysis has also been invoked to evaluate differences between alternative conceptual models. Advancing multiple alternative flow models, sensitivity of transport predictions to parameter uncertainty is assessed through Monte Carlo simulations. The simulations are challenged by the distributed sources in each of the Corrective Action Units, by complex mass transfer processes, and by the size and complexity of the field- scale flow models. An efficient methodology utilizing particle tracking results and convolution integrals provides insitu concentrations appropriate for Monte Carlo analysis. Uncertainty in source releases and transport parameters including effective porosity, fracture apertures and spacing, matrix diffusion coefficients, sorption coefficients, and colloid load and mobility are considered. With the distributions of input uncertainties and output plume volumes, global analysis methods including stepwise regression, contingency table analysis, and classification tree analysis are used to develop sensitivity rankings of parameter uncertainties for each model considered, thus assisting a variety of decisions. The National Security Technologies, LLC component of this work is DOE/NV/25946--xxx and was done under contract number DE-AC52-O6NA25946 with the U.S. Department of Energy

  8. 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.

  9. 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.

  10. Conditions for forming a hydrogeological system of the artesian and free aquifers of the Avacha artesian basin (eastern Kamchatka).

    NASA Astrophysics Data System (ADS)

    Lazarev, V.

    2003-04-01

    The exploration area covers the southern part of the Avacha-Koryak volcano group and the Avacha depression, lying at its foot. On the territory of the Avacha depression, in the cities of Petropavlovsk-Kamchatsky and Elizovo and in the settlements there reside around almost three forth of Kamchatka Peninsula people. Here the question of the fresh water supply is quite actual. The Avacha-Koryak volcano group represents an isolated hydrogeological structure with its own replenishment conditions, localization, transit and unloading of underground water, which is the area of the water supply for the artesian basin connected with the Avacha depression. In course of the carried out explorations there were reconstructed the history of the porous quaternary deposits of the Avacha depression and the hydrogeological system connected with it, cleared up their genesis and age. Most part of the porous deposits consists of products of the Avacha-Koryak group or is connected to them. Location of the boundaries between water reserving and waterproof beds were established both over a section and the area. Thickness and position of screening layers on the path of underground water flow motion that contributes to the water head in them have been determined. Obtained data allow defining the most perspective area for searching large fields of fresh underground water. In one plot of this area there was found a field, which is regarded as the main source for water supply for Petropavlovsk-Kamchatsky and the settlements around.

  11. Hydrogeology of the Cross Bar Ranch well-field area and projected impact of pumping, Pasco County, Florida

    USGS Publications Warehouse

    Hutchinson, C.B.

    1985-01-01

    The hydrogeology and development of a groundwater flow model are described for a 121-square-mile area in Pasco County, Florida. The hydrogeologic framework consists of the surficial aquifer--a thin blanket of sand--and the underlying carbonates of the upper Floridian aquifer. The aquifers are separated by a leaky sand and clay confining unit. The Cross Bar Ranch well field occupies 13 square miles and contains 17 production wells averaging about 700 feet deep and tapping the upper Florida aquifer. Procedures to calibrate, test sensitivity to input parameters, and validate the model 's accuracy are described. Pumping at 30 million gallons per day should result in 5 feet of decline in the water table of the surficial aquifer over an 8-square-mile area and in the potentiometric surface of the Upper Florida aquifer over a 15-square-mile area. Under the 45-million-per-day maximum permitted rate, drawdown should be 5 feet or more in the water table and potentiometric surface over areas of 16 and 28 square miles, respectively. At the center of pumping, water levels could decline 15 to 25 feet. The surficial aquifer could possibly be completely dewatered in a small area of the well field when pumping is at the maximum rate. (USGS)

  12. Hydrogeological and geophysical study for deeper groundwater resource in quartzitic hard rock ridge region from 2D resistivity data

    NASA Astrophysics Data System (ADS)

    Kumar, Dewashish; Rao, V. Ananda; Sarma, V. S.

    2014-04-01

    Electrical resistivity method is a versatile and economical technique for groundwater prospecting in different geological settings due to wide spectrum of resistivity compared to other geophysical parameters. Exploration and exploitation of groundwater, a vital and precious resource, is a challenging task in hard rock, which exhibits inherent heterogeneity. In the present study, two-dimensional Electrical Resistivity Tomography (2D-ERT) technique using two different arrays, viz., pole-dipole and pole-pole, were deployed to look into high signal strength data in a tectonically disturbed hard rock ridge region for groundwater. Four selected sites were investigated. 2D subsurface resistivity tomography data were collected using Syscal Pro Switch-10 channel system and covered a 2 km long profile in a tough terrain. The hydrogeological interpretation based on resistivity models reveal the water horizons trap within the clayey sand and weathered/fractured quartzite formations. Aquifer resistivity lies between ˜3-35 and 100-200 ?m. The results of the resistivity models decipher potential aquifer lying between 40 and 88 m depth, nevertheless, it corroborates with the static water level measurements in the area of study. The advantage of using pole-pole in conjunction with the pole-dipole array is well appreciated and proved worth which gives clear insight of the aquifer extent, variability and their dimension from shallow to deeper strata from the hydrogeological perspective in the present geological context.

  13. 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.

  14. An integrated study of the hydrogeology of volcanic islands using helicopter borne transient electromagnetic: Application in the Galápagos Archipelago

    NASA Astrophysics Data System (ADS)

    Auken, Esben; Violette, Sophie; d'Ozouville, Noémi; Deffontaines, Benoît; Sørensen, Kurt I.; Viezzoli, Andrea; de Marsily, Ghislain

    2009-10-01

    The hydrology of volcanic islands is poorly characterized due to their complex internal structure and challenging access. The Galápagos Islands, an isolated basaltic environment with unique ecosystems and growing anthropogenic pressure, suffer from scarcity of freshwater resources and from the lack of fundamental knowledge on their hydrology. To overtake these constraints and provide fresh water to the population, a geophysical survey and a hydroclimatologic network at watershed scale have been performed over Santa Cruz. An innovative helicopter borne transient electromagnetic method permitted a quasi-3D (an inversion scheme allowing for a 3D model description but with a local 1D forward algorithm) resistivity mapping of the massif and the identification of its hydrogeological potential. The latter is composed of a perched aquifer on the windward mountainside and a basal aquifer. Our hydroclimatologic network provided useful data records and allowed us to characterize the hydrodynamic properties of the basal aquifer. The geophysical data allow us to precise its extension. The conceptual hydrogeological model proposed for Santa Cruz confirms one of the models proposed for Le Piton de la Fournaise (Réunion Island). It has now to be confirmed with boreholes and a detailed geochemical study including noble gas analysis.

  15. The gravitational accommodation of the Chicxulub crater and its influence on the development of hydrogeological parameters in Yucatan

    NASA Astrophysics Data System (ADS)

    Rebolledo-Vieyra, M.; Iglesias-Prieto, R.; Marino-Tapia, I.

    2013-05-01

    The northern Yucatan Peninsula is characterized by a young and dynamic karstic system that yields very high secondary porosity and permeability. However, we have little, if none, knowledge about the hydraulic conductivity and the amount of groundwater being discharged in to ocean. Here we present and estimation of the hydraulic conductivity and quantity of groundwater being discharged by the northern Yucatan Peninsula coastal aquifer into the Gulf of Mexico, using the Sea Surface Temperature (SST) Images offshore the Yucatan coast, where we have detected a thermal anomaly that appears few hours after heavy rainfall in northern Yucatan. We associated these thermal anomalies of the SST to the groundwater being discharged into the ocean. To test our hypothesis we conducted a review of extreme rainfall events in the last 10 years; in parallel we used data from pressure and flow direction gauges installed in a known submarine groundwater discharge (SGD) to estimate the hydraulic conductivity and the quantity of groundwater being discharged. The satellite imagery and the rainfall data, allowed us to estimate the time lag between the rainfall and the SGD beginning, along with the hydraulic data from the gauges we have estimated the hydrogeological parameters of the coastal aquifer. This data is very important to contribute to the understanding the hydrogeological setting of the Yucatan coastal aquifer and its implications of the impact of human activities on the water quality.

  16. Hydrogeologic subdivision of the Wolfcamp Series and Pennsylvanian System of the Deaf Smith study area, Texas: Revision 1, Topical report

    SciTech Connect

    Siminitz, P.C.; Warman, E.A.

    1987-07-01

    The Pennsylvanian-Wolfcamp section in the Palo Duro Basin includes brine aquifers that are considered to be the most important ground-water flow paths in the deep-basin system. This particular study area comprises eight counties in Texas, centered in Potter County (and including Deaf Smith County). Underground patterns of rock distribution are delineated from a hydrologic perspective and at a level of detail appropriate for numerical modeling of regional ground-water flow. In this study, hydrogeologic units have been defined as mappable, physically continuous rock bodies that function in bulk as water-transmitting or water-retarding units relative to adjacent rocks. Interpretations are made primarily from geophysical logs. Hydrologic characteristics are assessed on the basis of properties typically associated with certain lithologies (e.g., sandstones are more pervious than shales) and on the basis of gross variations in effective porosity (particularly in carbonate sequences). In this report, the Pennsylvanian-Wolfcamp section is subdivided into 41 hydrogeologic units. These units do not constitute a classical or definitive breakdown of the Pennyslvanian-Wolfcamp section. 12 refs., 87 figs., 1 tab.

  17. Digital surfaces and hydrogeologic data for the Mesozoic through early Tertiary rocks in the Southeastern Coastal Plain in parts of Mississippi, Alabama, Georgia, South Carolina, and Florida

    USGS Publications Warehouse

    Cannon, Debra M.; Bellino, Jason C.; Williams, Lester J.

    2012-01-01

    A digital dataset of hydrogeologic data for Mesozoic through early Tertiary rocks in the Southeastern Coastal Plain was developed using data from five U.S. Geological Survey (USGS) reports published between 1951 and 1996. These reports contain maps and data depicting the extent and elevation of the Southeast Coastal Plain stratigraphic and hydrogeologic units in Florida and parts of Mississippi, Alabama, Georgia, and South Carolina. The reports are: Professional Paper 1410-B (Renken, 1996), Professional Paper 1088 (Brown and others, 1979), Professional Paper 524-G (Applin and Applin, 1967), Professional Paper 447 (Applin and Applin, 1965), and Circular 91 (Applin, 1951). The digital dataset provides hydrogeologic data for the USGS Energy Resources Program assessment of potential reservoirs for carbon sequestration and for the USGS Groundwater Resource Program assessment of saline aquifers in the southeastern United States. A Geographic Information System (ArcGIS 9.3.1) was used to construct 33 digital (raster) surfaces representing the top or base of key stratigraphic and hydrogeologic units. In addition, the Geographic Information System was used to generate 102 geo-referenced scanned maps from the five reports and a geo-database containing structural and thickness contours, faults, extent polygons, and common features. The dataset also includes point data of well construction and stratigraphic elevations and scanned images of two geologic cross sections and a nomenclature chart.

  18. Statistical classification of hydrogeologic regions in the fractured rock area of Maryland and parts of the District of Columbia, Virginia, West Virginia, Pennsylvania, and Delaware

    USGS Publications Warehouse

    Fleming, Brandon J.; LaMotte, Andrew E.; Sekellick, Andrew J.

    2013-01-01

    Hydrogeologic regions in the fractured rock area of Maryland were classified using geographic information system tools with principal components and cluster analyses. A study area consisting of the 8-digit Hydrologic Unit Code (HUC) watersheds with rivers that flow through the fractured rock area of Maryland and bounded by the Fall Line was further subdivided into 21,431 catchments from the National Hydrography Dataset Plus. The catchments were then used as a common hydrologic unit to compile relevant climatic, topographic, and geologic variables. A principal components analysis was performed on 10 input variables, and 4 principal components that accounted for 83 percent of the variability in the original data were identified. A subsequent cluster analysis grouped the catchments based on four principal component scores into six hydrogeologic regions. Two crystalline rock hydrogeologic regions, including large parts of the Washington, D.C. and Baltimore metropolitan regions that represent over 50 percent of the fractured rock area of Maryland, are distinguished by differences in recharge, Precipitation minus Potential Evapotranspiration, sand content in soils, and groundwater contributions to streams. This classification system will provide a georeferenced digital hydrogeologic framework for future investigations of groundwater availability in the fractured rock area of Maryland.

  19. An overview of the Tertiary geology and hydrogeology of the northern part of the Arabian Gulf region with special reference to Kuwait

    Microsoft Academic Search

    A. Mukhopadhyay; J. Al-Sulaimi; E. Al-Awadi; F. Al-Ruwaih

    1996-01-01

    Tertiary sediments constitute the main source of usable groundwater in Kuwait. Tectonics, depositional environment, lithology and the hydrogeology of these sediments have been reviewed on a regional scale, with special reference to Kuwait. The review showed that Kuwait was situated at the boundary of the stable shelf towards southwest and the unstable shelf towards northeast throughout the Tertiary period. The

  20. Hydrogeologic controls imposed by mechanical stratigraphy in layered rocks of the Châteauguay River Basin, a U.S.Canada transborder aquifer

    Microsoft Academic Search

    Roger Morin; Réjean Godin; Miroslav Nastev; Alain Rouleau

    2007-01-01

    The Châteauguay River Basin delineates a transborder watershed with roughly half of its surface area located in northern New York State and half in southern Québec Province, Canada. As part of a multidisciplinary study designed to characterize the hydrogeologic properties of this basin, geophysical logs were obtained in 12 wells strategically located to penetrate the four major sedimentary rock formations

  1. The Hydrogeologic Properties of Potsdam Sandstone in the Chateauguay River Basin and Their Implications Regarding U.S.Canada Transboundary Water Issues

    Microsoft Academic Search

    R. H. Morin; J. H. Williams; M. Nastev

    2009-01-01

    Proper management of water resources across shared boundaries requires a fundamental understanding of the hydrogeologic system underlying the region. In the case of the Chateauguay River Basin, a transboundary watershed with roughly half of its surface area located in northern New York State (USA) and half in southern Quebec Province (Canada), the Potsdam Sandstone forms a regional fractured-rock aquifer that

  2. Study of radium-226 and radon-222 concentrations in ground water near a phosphate mining and manufacturing facility with emphasis on the hydrogeologic characteristics of the area

    Microsoft Academic Search

    B. F. Mitsch; J. E. Jr. Watson; J. A. Hayes

    1984-01-01

    Samples of water from wells located near a phosphate mining and manufacturing facility were collected and analyzed for radium-226 and radon-222. Chemical separation and emanation techniques were used in the analyses. Results indicated that mining and manufacturing were not having a detrimental effect on the radionuclide concentrations in the ground water of the area. Natural hydrogeologic factors can account for

  3. Hydrogeologic investigation and establishment of a permanent multi-observational well network in Aiken, Allendale, and Barnwell Counties, South Carolina. Phase VIII

    Microsoft Academic Search

    J. A. Gellici; C. E. Gawne

    1996-01-01

    The Lower Savannah River Project was established in 1986 to improve our understanding of the hydrogeologic conditions in west-central South Carolina. Six progress reports have been written since 1987. This report covers the period from July 1, 1994, to June 30, 1995. During the current phase, work focused on locating and procuring suitable sites for future well clusters; drafting well-construction

  4. Application of a resistivity survey and geographical information system (GIS) analysis for hydrogeological zoning of a piedmont area, Himalayan foothill region, India

    Microsoft Academic Search

    M. Israil; Mufid Al-Hadithi; D. C. Singhal

    2006-01-01

    A Geographical Information System (GIS) has been used for the integration of the results of 70 vertical electrical soundings and hydrogeological data in the piedmont zone of the Himalayan foothills region of Uttaranchal, India. Indian remote sensing (IRS) LISS-III data has been used to prepare thematic maps for the geomorphology and slope maps of the area. The ranges of electrical

  5. 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.

  6. Geologic framework and hydrogeologic characteristics in the southern part of the Rancho Diana Natural Area, northern Bexar County, Texas, 2008-10

    USGS Publications Warehouse

    Clark, Allan K.; Morris, Robert R.

    2011-01-01

    The area designated by the city of San Antonio as the Rancho Diana Natural Area is in northern Bexar County, near San Antonio, Texas. During 2008-10, the U.S. Geological Survey, in cooperation with the city of San Antonio, documented the geologic framework and mapped the hydrogeologic characteristics for the southern part of the Rancho Diana Natural Area. The geologic framework of the study area and its hydrogeologic characteristics were documented using field observations and information from previously published reports. Many of the geologic and hydrogeologic features were found by making field observations through the dense vegetation along gridlines spaced approximately 25 feet apart and documenting the features as they were located. Surface geologic features were identified and hydrogeologic features such as caves, sinkholes, and areas of solutionally enlarged porosity were located using hand-held Global Positioning System units. The location data were used to create a map of the hydrogeologic subdivisions and the location of karst features. The outcrops of the Edwards and Trinity aquifer recharge zones were mapped by using hydrogeologic subdivisions modified from previous reports. All rocks exposed within the study area are of sedimentary origin and Lower Cretaceous in age. The valley floor is formed in the cavernous member of the upper Glen Rose Limestone of the Trinity Group. The hills are composed of the basal nodular member, dolomitic member, Kirschberg evaporite member, and grainstone member of the Kainer Formation of the Edwards Group. Field observations made during this study of the exposed formations and members indicate that the formations and members typically are composed of mudstones, wackestones, packstones, grainstones, and argillaceous limestones, along with marls. The upper Glen Rose Limestone is approximately 410 to 450 feet thick but only the upper 70 feet is exposed in the study area. The Kainer Formation is approximately 255 feet thick in the study area and is composed of, in ascending order, the basal nodular member, dolomitic member, Kirschberg evaporite member, and grainstone member. The Edwards and Trinity aquifers contain a combination of fabric-selective and not-fabric-selective porosities. Porosity types observed in the study area that can increase the effective porosity and increase permeability include solutionally enlarged caves, sinkholes, fractures, bedding planes, channels, molds and vugs. Caves found during hydrogeologic mapping might have been spring discharge points, but sufficient downcutting over geologic time in the rocks has occurred so that springs discharge at lower elevations near the creek channel. The mapped caves, sinkholes, and other areas of solutionally enlarged porosity might facilitate recharge during large storm events when runoff occurs on the hillsides; additional areally distributed recharge in the study area occurs as a result of infiltration.

  7. Hydrogeologic Factors Affecting the Transport of Nutrients and Pesticides to Shallow Ground Water and Small Streams in the Mid-Atlantic Coastal Plain, USA

    NASA Astrophysics Data System (ADS)

    Denver, J. M.; Ator, S. W.; Krantz, D. E.; Newell, W. L.

    2001-05-01

    Defining the spatial variability of hydrogeologic settings is fundamental to understanding the processes that potentially affect chemical fate and transport for many types of environmental studies. This is particularly true in areas such as the Mid-Atlantic Coastal Plain, where surficial sediments are heterogeneous on a regional scale, but often considered homogeneous for data interpretation. A regional surficial hydrogeologic framework was developed for the non-glaciated Mid-Atlantic Coastal Plain of New Jersey, Delaware, Maryland, Virginia, North Carolina, and the District of Columbia. Seven hydrogeologic subregions were defined based on a combination of physiography and the predominant texture of surficial geologic units. The subregions represent areas with similar geology, primarily siliciclastic sediments, along a continuum of hydrogeologic settings. The framework is intended as a template for explaining the spatial variability in regional water chemistry, for synthesizing water-quality analyses of nutrients and pesticides, and for designing future regional assessments of anthropogenic chemicals affecting shallow ground water and surface water. The transport of chemicals from the land surface to ground water and streams in the Coastal Plain and the transformations that occur along the way are related, in part, to the distribution of coarse to fine-grained sediments and organic matter, and the resulting redox characteristics in different hydrogeologic settings. Some subregions have more uniform and homogeneous hydrogeologic characteristics and support a relatively consistent set of processes that potentially affect the flow and chemistry of shallow ground water and small streams. For example, the Coastal Lowlands subregion flat, poorly drained and has low-gradient streams. There are numerous anoxic swamps and marshes, and the predominantly fine-grained surficial sediments contain abundant organic matter. These conditions affect chemical transport and transformation through processes such as denitrification and sorption of pesticides onto organic matter. In contrast, one of the Middle Coastal Plain subregions is well drained with moderate relief and surficial sediments of primarily quartz sand. Stream channels are relatively sandy, but may have abundant organic matter. Oxidizing conditions are common throughout the shallow ground-water system and the potential for sorption is generally low. Ground water in the Middle Coastal Plain subregion is particularly vulnerable to the leaching of excess nitrogen and soluble pesticide residues from land applications, although the mobility of certain chemicals may be limited by organic matter and the development of anoxic zones in and near streambeds. These two subregions represent end-member hydrogeologic conditions that occur to different degrees in each of the other five framework subregions.

  8. 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).

  9. 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

  10. Development, Calibration and Deployment of an Electromagnetic Flowmeter for Cross-Hole Hydrogeologic Experiments

    NASA Astrophysics Data System (ADS)

    Slovacek, A. E.; Fisher, A. T.; Kirkwood, W.; Wheat, C. G.; Maughan, T.; Gomes, K.

    2011-12-01

    We developed an autonomous electromagnetic flowmeter as part of a cross-hole hydrogeologic experiment using subseafloor borehole observatories (CORKs) that penetrate into the volcanic ocean crust. The cylindrical flowmeter is adapted from a conventional industrial tool and hardened for use at water depths up to 6000 m. In addition, the electronics were modified with a new power controller, and a data logger and communication board was added to enable data storage and long-term, autonomous use for up to eight years. The flowmeter generates a magnetic field and measures a voltage gradient that is created across the orifice as water moves through it. This kind of tool is ideally suited for use in the deep sea, particularly for measuring hydrothermal fluids emanating from the ocean crust, because it requires no moving parts, places no obstructions along the flow path, gives total flow volume as well as instantaneous flow rate, and is highly accurate across a large dynamic range, including bi-directional flow. This flowmeter was deployed on a CORK wellhead using an adapter and ring clamp system located above a 4-inch ball valve. The ball valve can be opened to permit flow (from an overpressured formation) out of the CORK and into the overlying ocean. A polyvinyl chloride "chimney" positioned vertically above the flowmeter is instrumented with autonomous temperature loggers to permit an additional estimate of fluid flow rates with time, based on heat loss during fluid ascent, and to facilitate fluid sampling. Calibration of the new flowmeter was completed in two stages: tank testing using a pump at flow rates of 0.5 to 1.2 L/s, and by lowering the flowmeter on a wireline at sea at rates equivalent to 0.5 to 5.2 L/s. A cross plot of apparent and reference flow rates obtained during calibration indicates a highly linear instrument response. Comparison of instantaneous (once per minute) and integrated (total flow) data collected during calibration indicates good agreement, although the instantaneous data tended to be noisy because of irregularity of flow (turbulence). The flowmeter was deployed in Summer 2011 on a CORK installed in IODP Hole 1362B, on the eastern flank of the Juan de Fuca ridge. Once the flowmeter was attached to the wellhead, the underlying ball valve was opened, which allowed overpressured fluids from the permeable ocean crust to flow upward and out of the seafloor at 5 to 10 L/s (estimated rate). Changes in formation fluid pressure resulting from this flow are being monitored in four additional CORKs located 310 to 2320 m away from Hole 1362B, which will allow large-scale, directional assessment of formation properties. The flowmeter is recording data for instantaneous flow rate and total flow once per hour, and will be recovered to permit collection and analysis of experimental data during a servicing visit in Summer 2012.

  11. 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).

  12. Myth and Reality in Hydrogeological Site Characterization at DD and R Sites

    SciTech Connect

    Rubin, Yoram [Dept. of Civil and Environmental Engineering, UC Berkeley, California, 94720 (United States)

    2008-01-15

    The science of hydrogeological site characterization has made significant progress over the last twenty years. Progress has been made in modeling of flow and transport in the heterogeneous subsurface, in understanding of the complex patterns of geological heterogeneity and in measurement technologies. Modeling of uncertainty has also advanced significantly, in recognition of the inherent limitations of subsurface characterization. Much less progress has been made in transforming this progress into practice, where characterization is determined to a large extent by regulations. Environmental regulations have not progressed as much as the science, for example, in recognizing uncertainty. As such, practitioners are less inclined to adopt advanced, science-based solutions, this opening the door for myths and conflicts. Myths develop where the science base is perceived to be weak, whereas conflicts arise in the face of a disconnect between the science and the regulations. Myths translate to ad-hoc solutions and misplaced empiricism, as well as to unjustified reliance on field experience, to the detriment of D and DR. This paper explores the roots for this situation and identifies ideas that may help in bridging the gap between research and applications. A rational approach for DD and R is needed that will encourage innovation in site characterization, reduce costs and accelerate completion. Such an approach needs to include several elements. DD and R regulations need to recognize the various aspects of uncertainty inherent to site characterization, and as such, should be formulated using probabilistic concepts. One of the immediate benefits will be in allowing a gradual approach for data acquisition in DD and R sites: decisions can be made even under the most severe data limitations, and can be modified as additional data become available. The definition of risk is another major element. There is no universal definition of risk or of a methodology to define risk. Different sites justify different definitions, depending on many environmental, economical and social factors. Despite the lack of consensus, it seems that a good place to start is in fact to recognize that there is a room for all these factors, and a need to balance between them. As experience is gained, through research and discussions among DD and R stakeholders, this may become less of a challenge. Regulations need to recognize the possibility of developing alternative, site-specific characterization strategies based on the various length and time scales that define specific environmental problems, including length scales of heterogeneity, source dimensions and distance to environmental targets. For example, point and distributed sources justify different characterization strategies. Development of problem- or site-specific strategies will create the context for defining innovative efficient DD and R strategies. Innovation in characterization can will also follow from recognizing the specific physiological aspects of the toxins and the related uncertainty. This will open the door for improving risk characterization not only from the hydrologic perspective, but also form the physiologic one.

  13. 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.

  14. Integration of Thirty Years of Hydrogeological Investigations at the Waste Isolation Pilot Plant Site

    NASA Astrophysics Data System (ADS)

    Beauheim, R. L.; Domski, P. S.; Holt, R. M.; Powers, D. W.

    2008-12-01

    Hydrogeological research has been going on at the Waste Isolation Pilot Plant (WIPP), the U.S. Department of Energy's deep geologic repository for transuranic and mixed waste in southeastern New Mexico, for over thirty years. The main focus of the research has been on the Culebra Dolomite Member of the Rustler Formation, a 7-m-thick fractured unit that would be the primary groundwater transport pathway for radionuclides released from the WIPP repository by inadvertent human intrusion. Since 1977, 90 wells have been completed to the Culebra on 63 drilling pads. Hydraulic tests have been performed in all of the wells, ranging from single-well slug and pumping tests to long-term (19-121 days) pumping tests with observation wells up to 9.5 km away. These tests have shown that Culebra transmissivity (T) varies over 10 orders of magnitude. Single-well injection-withdrawal, two-well recirculating, and multiwell convergent-flow tracer tests have been performed at six locations. Fluid electrical conductivity logging has been performed to identify the most transmissive sections of the Culebra, and a colloidal borescope has been used to identify specific flowing fractures. In addition to studies focused on groundwater flow and transport, geological, sedimentological, hydrogeochemical, and geophysical investigations have also been performed. Variations in Culebra T have been related to dissolution of the underlying Salado Formation, the presence/absence of gypsum cements, the presence or absence of halite in Rustler members above and below the Culebra, and overburden thickness. Different types of porosity (fractures, vugs, interparticle, intercrystalline) have been found to be significant for both flow and transport. Culebra water chemistry shows significant spatial variation, with total dissolved solids ranging from 3,000 to 300,000 mg/L. Five distinct hydrochemical facies have been identified, ranging from high ionic strength syndepositional Na-Mg Cl brines to low ionic strength CaSO4 waters, thought to represent relatively recent recharge through gypsum karst, to brines contaminated with potash-processing effluent. Geophysical logs from an abundance of oil and gas wells around the WIPP site have been used to map facies boundaries within other Rustler members that can be related to Culebra hydrology. The results of these three decades of study have been integrated into a conceptual model for Culebra hydrology. Some of these studies have been carried out in collaboration with university researchers, and all of the data from these investigations are freely available. *Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04- 94AL85000. This research is funded by WIPP programs administered by the Office of Environmental Management (EM) of the U.S DOE.

  15. 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.

  16. 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

  17. 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.

  18. 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

  19. 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

  20. 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)

  1. Fracture related-fold patterns analysis and hydrogeological implications: Insight from fault-propagation fold in Northwestern of Tunisia

    NASA Astrophysics Data System (ADS)

    Sanai, L.; Chenini, I.; Ben Mammou, A.; Mercier, E.

    2015-01-01

    The spatial distribution of fracturing in hard rocks is extremely related to the structural profile and traduces the kinematic evolution. The quantitative and qualitative analysis of fracturing combined to GIS techniques seem to be primordial and efficient in geometric characterization of lineament's network and to reconstruct the relative timing and interaction of the folding and fracturing histories. Also a detailed study of the area geology, lithology, tectonics, is primordial for any hydrogeological study. For that purpose we used a structural approach that consist in comparison between fracture sets before and after unfolding completed by aerospace data and DEM generated from topographic map. The above methodology applied in this study carried out in J. Rebia located in Northwestern of Tunisia demonstrated the heterogeneity of fracturing network and his relation with the fold growth throught time and his importance on groundwater flow.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. The usefulness of outcrop analogue air permeameter measurements for analysing aquifer heterogeneity: testing outcrop hydrogeological parameters with independent borehole data

    NASA Astrophysics Data System (ADS)

    Rogiers, B.; Beerten, K.; Smeekens, T.; Mallants, D.; Gedeon, M.; Huysmans, M.; Batelaan, O.; Dassargues, A.

    2013-07-01

    Outcropping sediments can be used as easily accessible analogues for studying subsurface sediments, especially to determine the small-scale spatial variability of hydrogeological parameters. The use of cost-effective in situ measurement techniques potentially makes the study of outcrop sediments even more attractive. We investigate to what degree air permeameter measurements on outcrops of unconsolidated sediments can be a proxy for aquifer saturated hydraulic conductivity (K) heterogeneity. The Neogene aquifer in northern Belgium, known as a major groundwater resource, is used as case study. K and grain size data obtained from different outcropping sediments are compared with K and grain size data from aquifer sediments obtained either via laboratory analyses on undisturbed borehole cores (K and grain size) or via large-scale pumping tests (K only). This comparison shows a pronounced and systematic difference between outcrop and aquifer sediments. Part of this difference is attributed to grain size variations and earth surface processes specific to outcrop environments, including root growth, bioturbation, and weathering. Moreover, palaeoenvironmental conditions such as freezing-drying cycles and differential compaction histories will further alter the initial hydrogeological properties of the outcrop sediments. A linear correction is developed for rescaling the outcrop data to the subsurface data. The spatial structure pertaining to outcrops complements that obtained from the borehole cores in several cases. The higher spatial resolution of the outcrop measurements identifies small-scale spatial structures that remain undetected in the lower resolution borehole data. Insights in stratigraphic and K heterogeneity obtained from outcrop sediments improve developing conceptual models of groundwater flow and transport.

  7. Estimation of geohydraulic parameters from fractured shales and sandstone aquifers of Abi (Nigeria) using electrical resistivity and hydrogeologic measurements

    NASA Astrophysics Data System (ADS)

    Ebong, Ebong D.; Akpan, Anthony E.; Onwuegbuche, Anthony A.

    2014-08-01

    Geohydraulic parameters are essential elements in groundwater resource management and conservation. Most of these parameters especially the hydraulic conductivity and transmissivity are usually estimated from pumping test carried out on drilled boreholes. This paper presents a study conducted in Abi area of the Ikom-Mamfe Embayment with the objective of estimating aquifer parameters from 30 evenly distributed vertical electrical soundings using the Schlumberger configuration and hydrogeologic measurements from 28 boreholes within the area as an alternative way of generating an initial data for groundwater characterisation and quality assessment in the area. The results showed low resistivity ?45 ?m, hydraulic conductivity ?2.0 × 10-5 m/s (?1.7 m/day) and transmissivity ?5.2 × 10-4 m2/s (?45 m2/day) for the water-bearing aquifer horizons in the northeastern and northwestern parts of the study area due to the nature of the aquifer system that were predominantly fractured shale. The sand based aquifers had higher values in the neighbourhood of ?100-800 ?m, ?4.0 × 10-5-1.0 × 10-4 m/s (?3.46-9.04 m/day) and ?6.94 × 10-4-3.81 × 10-3 m2/s (?60-330 m2/day) for the respective parameters mentioned above. The potability of the groundwater system as observed from hydrogeologic measurements of water samples from most boreholes were relatively poor, having electrical conductivity and total dissolved solids values of ?250-931.0 ?S/cm and ?500-623.77 mg/l respectively due to the influence of clay minerals within the aquifer horizon. Some of the vertical electrical sounding points were taken in the vicinity were pumping tests and lithologic data were available for adequate comparison of the results.

  8. High-resolution, Global Hydrogeology Maps (GHyM) of near-surface permeability, porosity and water table type

    NASA Astrophysics Data System (ADS)

    Gleeson, T. P.; Moosdorf, N.; Hartmann, J.; Van Beek, L. P.

    2013-12-01

    The lack of robust, spatially-distributed subsurface data is key obstacle limiting the implementation of complex and realistic groundwater dynamics into global land surface, hydrologic and climate models. We map and analyze permeability, porosity and water table ratio globally and at high-resolution for the first time. Permeability and porosity are crucial hydrogeologic parameters while the water table ratio is a dimensionless ratio that predicts how the water table functions, either as topography-controlled or recharge-controlled. The new permeability and porosity maps are based on a recently completed high-resolution global lithology map with important refinements in regions of weathered tropical soils and permafrost regions. We use the high-resolution global permeability map as well as other data sets to compute the high resolution water table ratio globally. The spatially-distributed mean logarithmic permeabilities for the globe (assuming permafrost regions have negligible permeability) is -13.55 × 1.9 m2 which is consistent with previous estimates of shallow crustal permeability. The water-table type is generally contiguous over large regions rather than fragmented across the landscape and that much of the globe is topography-controlled water tables. Therefore the water table is a subdued replica of topography in many more regions than the water table is recharge controlled and disconnected from topography. We hope the new, freely-available maps of permeability, porosity and water table type, called the Global Hydrogeology Maps (GHyM), will enable further integration of groundwater dynamics into land surface, hydrologic and climate models.

  9. 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.

  10. Introduction: Special Issue: Discussions on Metahydrogeology: Research Stocktaking or Identity Crisis? Essays on the Once and Future Merit of Research in Hydrogeology

    SciTech Connect

    Ginn, Timothy R.; Scheibe, Timothy D.

    2008-01-01

    We believe that the Journal of Hydrologic Engineering should serve as the primary outlet for hydrogeological research on the engineering aspects—including applications and science—of subsurface hydrology. Our journal fills the interval between the more theoretical and the more applied contexts of hydrogeology for which numerous print outlets exist. We begin drawing together our strategy for invigorating this role in the journal’s future by first holding a discourse on the role of research itself in hydrogeology. This discourse continues an already vigorous discussion that has been ongoing in the literature and is characterized by one primary fact: papers in hydrology literature are cited rarely, relative to a variety of expectations. Research progress in many fields of environmental science and engineering has grown more inclusive of lateral, interdisciplinary contributions while exhibiting commonly valued vertical contributions with less frequency. At the same time, the conventional role of research, its intrinsic value—and especially its value to practical applied science and engineering, has come under increasing scrutiny and criticism. Public discussions and debates addressing aspects of this critique in recent years have appeared in the ASCE Journal of Environmental Engineering 127(4, 5, 9); Ground Water 39(4) and 40(3); Stochastic Environmental Research and Risk Assessment 18(4); and the Hydrogeology Journal 13(1). More recently, a quantitative bibliometric analysis of the impact of publishing in hydrology (Koutsoyiannis and Kundzewicz 2007) concludes that the impact of a hydrological technical paper can indeed be satisfactorily (but not ideally) measured by its number of citations. However, these authors also find that “the quantification of the quality and importance of research achievements is very difficult, if not impossible.” In either case, according to a personal communication from V. Klemes, the fact that most papers are rarely cited means that most of the citations that do exist are rarely conveyed. These studies raise a number of questions. Is publishing, for the most part, a waste of time outside of academic merit? Is hydrogeology a “mature science”? Is progress really being made on longstanding hydrogeological problems? This special issue is intended not only to provide a robust platform for continuating the debate surrounding these and related questions but also to reinitialize the role of the Journal of Hydrologic Engineering in disseminating contributions to hydrogeological engineering science and practice. As a continuation of this discussion, the issue editors hosted a session at the fall 2005 meeting of the American Geophysical Union (http://www.agu.org/meetings/fm05/?pageRequest=search&show =detail&sessid=362) encouraging debate about the value of research, academic and otherwise, in hydrogeology. This session involved a small sample of some of the top thinkers on these issues today, representing a wide range of perspectives. Included in this special issue are essays and philosophical commentaries by the participants in that session. These contributions illuminate ways that research, publishing, teaching, practice, and scholarship may evolve to increase the value of research to society, ranging from basic science to engineering hydrogeology, worldwide.

  11. Hydrogeologic framework of the Wood River Valley aquifer system, south-central Idaho

    USGS Publications Warehouse

    Bartolino, James R.; Adkins, Candice B.

    2012-01-01

    The Wood River Valley contains most of the population of Blaine County and the cities of Sun Valley, Ketchum, Hailey, and Bellevue. This mountain valley is underlain by the alluvial Wood River Valley aquifer system, which consists primarily of a single unconfined aquifer that underlies the entire valley, an underlying confined aquifer that is present only in the southernmost valley, and the confining unit that separates them. The entire population of the area depends on groundwater for domestic supply, either from domestic or municipal-supply wells, and rapid population growth since the 1970s has caused concern about the long-term sustainability of the groundwater resource. As part of an ongoing U.S. Geological Survey effort to characterize the groundwater resources of the Wood River Valley, this report describes the hydrogeologic framework of the Wood River Valley aquifer system. Although most of the Wood River Valley aquifer system is composed of Quaternary-age sediments and basalts of the Wood River Valley and its tributaries, older igneous, sedimentary, or metamorphic rocks that underlie these Quaternary deposits also are used for water supply. It is unclear to what extent these rocks are hydraulically connected to the main part of Wood River Valley aquifer system and thus whether they constitute separate aquifers. Paleozoic sedimentary rocks in and near the study area that produce water to wells and springs are the Phi Kappa and Trail Creek Formations (Ordovician and Silurian), the Milligen Formation (Devonian), and the Sun Valley Group including the Wood River Formation (Pennsylvanian-Permian) and the Dollarhide Formation (Permian). These sedimentary rocks are intruded by granitic rocks of the Late Cretaceous Idaho batholith. Eocene Challis Volcanic Group rocks overlie all of the older rocks (except where removed by erosion). Miocene Idavada Volcanics are found in the southern part of the study area. Most of these rocks have been folded, faulted, and metamorphosed to some degree, thus rock types and their relationships vary over distance. Quaternary-age sediment and basalt compose the primary source of groundwater in the Wood River Valley aquifer system. These Quaternary deposits can be divided into three units: a coarse-grained sand and gravel unit, a fine-grained silt and clay unit, and a single basalt unit. The fine- and coarse-grained units were primarily deposited as alluvium derived from glaciation in the surrounding mountains and upper reaches of tributary canyons. The basalt unit is found in the southeastern Bellevue fan area and is composed of two flows of different ages. Most of the groundwater produced from the Wood River Valley aquifer system is from the coarse-grained deposits. The altitude of the pre-Quaternary bedrock surface in the Wood River Valley was compiled from about 1,000 well-driller reports for boreholes drilled to bedrock and about 70 Horizontal-to-Vertical Spectral Ratio (HVSR) ambient-noise measurements. The bedrock surface generally mimics the land surface by decreasing down tributary canyons and the main valley from north to south; it ranges from more than 6,700 feet in Baker Creek to less than 4,600 feet in the central Bellevue fan. Most of the south-central portion of the Bellevue fan is underlain by an apparent topographically closed area on the bedrock surface that appears to drain to the southwest towards Stanton Crossing. Quaternary sediment thickness ranges from less than a foot on main and tributary valley margins to about 350 feet in the central Bellevue fan. Hydraulic conductivity for 81 wells in the study area was estimated from well-performance tests reported on well-driller reports. Estimated hydraulic conductivity for 79 wells completed in alluvium ranges from 1,900 feet per day (ft/d) along Warm Springs Creek to less than 1 ft/d in upper Croy Canyon. A well completed in bedrock had an estimated hydraulic conductivity value of 10 ft/d, one well completed in basalt had a value of 50 ft/d, and three wells completed in the confined system had values ranging from 32 to 52 ft/

  12. 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

  13. Hydrogeology and simulation of ground-water flow at the South Well Field, Columbus, Ohio

    USGS Publications Warehouse

    Cunningham, W.L.; Bair, E.S.; Yost, W.P.

    1996-01-01

    The City of Columbus, Ohio, operates four radial collector wells in southern Franklin County. The 'South Well Field' is completed in permeable outwash and ice-contact deposits, upon which flow the Scioto River and Big Walnut Creek. The wells are designed to yield approximately 42 million gallons per day; part of that yield results from induced infiltration of surface water from the Scioto River and Big Walnut Creek. The well field supplied up to 30 percent of the water supply of southern Columbus and its suburbs in 1991. This report describes the hydrogeology of southern Franklin County and a tran sient three-dimensional, numerical ground-water- flow model of the South Well Field. The primary source of ground water in the study area is the glacial drift aquifer. The glacial drift is composed of sand, gravel, and clay depos ited during the Illinoian and Wisconsinan glaciations. In general, thick deposits of till containing lenses of sand and gravel dominate the drift in the area west of the Scioto River. The thickest and most productive parts of the glacial drift aquifer are in the buried valleys in the central and eastern parts of the study area underlying the Scioto River and Big Walnut Creek. Horizontal hydraulic conductivity of the glacial drift aquifer differs spa tially and ranges from 30 to 375 feet per day. The specific yield ranges from 0.12 to 0.30. The secondary source of ground water within the study area is the underlying carbonate bedrock aquifer, which consists of Silurian and Devonian limestones, dolomites, and shales. The horizontal hydraulic conductivity of the carbonate bedrock aquifer ranges from 10 to 15 feet per day. The storage coefficient is about 0.0002. The ground-water-flow system in the South Well Field area is recharged by precipitation, regional ground-water flow, and induced stream infiltration. Yearly recharge rates varied spatially and ranged from 4.0 to 12.0 inches. The three-dimensional, ground-water-flow model was constructed by use of the U.S. Geological Survey three-dimensional finite-difference ground-water-flow code. Recharge, boundary flux, and river leakage are the principal sources of water to the flow system. The study area is bounded on the north and south by streamlines, with flow entering the area from the east and west. Areal recharge is contributed throughout the study area, although a comparatively high percentage of precipitation reaches the water table in the area east of the Scioto River where little surface drain age exists. Ground-water flow is downward in the uplands of the Scioto River, and upward near the river in the glacial drift and carbonate bedrock aquifers. The numerical model contains 53 rows, 45 columns, and 3 layers. The uppermost two layers represent the glacial drift. The bottom layer represents the carbonate bedrock. The horizontal model grid is variably spaced to account for differences in available data and to simulate heads accurately in specific areas of interest. The length and width of grid cells range from 200 to 2,000 feet; the finer spacings are designed to increase detail in the areas near the collector wells. The model uses 7,155 active nodes. Measurements of water levels from October 1979 were used to represent steady-state conditions before municipal pumping at the well field began. Measurements made during March 1986 were used to represent steady-state conditions after commencement of pumping at the well field. Water levels measured during March 1986 - June 1991 were used for calibration targets in the transient simulations. The transient model was discretized into eight stress periods of 93 to 487 days on the basis of recharge, well-field pumpage, and available water-level data. Transient model calibration was based on seven sets of hydraulic-head measure ments made during March 1986 - June 1991. This time period includes large-scale increases in well- field production associated with a drought in the summer of 1988, an

  14. A little island with significant groundwater resources: hydrogeological and hydrogeochemical features of the Pianosa aquifer (Tuscan Archipelago, Italy)

    NASA Astrophysics Data System (ADS)

    Giannecchini, R.; Doveri, M.; Mussi, M.; Nicotra, I.; Puccinelli, A.

    2012-12-01

    The Pianosa Island is one of the seven islands of the Tuscan Archipelago, particularly known for its typical flat morphological structure. It is formed by Neogenic-Quaternary sedimentary rocks, mainly represented by superficial calcarenite and underlying marl and clayey marl. Despite the small extension of the island (just 10,2 km2 wide, coastal perimeter of approximately 18 km, maximum altitude of 29 m a.s.l.) and poor rainfall amount (the annual average is 480,7 mm in 1951-2002 period), the Pianosa aquifer is characterized by significant groundwater resources, which supported the presence of approximately 2,000 people at the end of Eighties. Nevertheless, the groundwater overexploitation and the land use (agricultural activity and cattle-breeding, associated to the local penal settlement activity) caused important sea-water intrusion and pollution phenomena. An improvement of such situation occurs since 1998, owing to the closing of the penal settlement and its activities. This pilot research intends to describe the hydrogeological and hydrogeochemical features of the Pianosa Island aquifer system and the groundwater quality several years after the penal settlement closing. The results of a multidisciplinary approach (hydrogeological, geochemical, isotopic) show that the groundwater recharge and circulation are substantially controlled by the hydro-structural conditions. The flat and permeable superficial calcarenite allows a high infiltration rate. The water table flow direction is generally W-E, in accordance with the dip direction of the stratigraphic contact between the calcarenite and the underlying impermeable marly-clayey rocks. However, the latter present conglomerate and sandstone intercalations, sometimes in contact (by angular unconformity) with the calcarenite, determining a general continuity in groundwater circulation, which is phreatic in the calcarenite, and confined in the conglomerate and sandstone horizons. A piezometric depression with values below the sea level has been identified in the eastern part of the island. The electric conductivity (EC) map confirms this hydrogeological structure. EC values above 1.000 ?S/cm are common in almost all the groundwater analyzed. An increase in groundwater salinity is observable in the eastern part of Pianosa, where the water table depression has been recognized. In agreement with the hydro-structural and water table conditions, the hydrogeochemical analyses confirm the recharge of the confined horizons (conglomerate and sandstone) by the superficial calcarenite. The isotopic data indicate that the aquifer system is recharged by the rainfall direct infiltration and there are not connections with the close Elba Island. Finally, the chemical analyses of most groundwater samples suggest an intermediate facies Na-Cl/Ca-HCO3, produced by the combination of the sea spray and the circulation in a prevalently carbonate aquifer (calcarenite). Clearly Na-Cl groundwater prevails in the eastern portion of the island, evidencing the seawater intrusion in the calcarenite, also confirmed by water table conditions and isotopic data.

  15. 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

  16. 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

  17. 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

  18. 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.

  19. Non-traditional and under-represented students in hydrogeology: Learning by discovery in an urban environment

    NSDL National Science Digital Library

    Laura Rademacher

    Background: In my experience, I have discovered many common roadblocks to non-traditional and under-represented student participation in hydrogeology: Time constraintsâmany students have complicated schedules and demands on their time that a traditional undergraduate does not have. For example, many of these students are working full time, and required experiences outside of the classroom often pose scheduling conflicts for students. Communication skillsâmany under-represented students arrive in the classroom with communication skills that are not fully developed. Students are often learning English as they are learning the complex vocabulary of hydrogeology. Math skillsâmany students are under prepared in math and/or have math phobias Fundingâmany students are unable to pay laboratory and field trip fees. I currently teach at minority serving institution. Here, I find that hands-on practice is the most successful learning experience for students. Students grasp concepts such as discharge, flux, and residence time more effectively when they are active participants in the learning process. The most effective method I have found for addressing these issues and encouraging under represented student participation in hydrogeology is to create student-designed group research projects. I used this strategy three quarters in a row, and the same students (as well as new students they recruit) continue to sign up for these courses. This trend, in addition to students' growing confidence in engaging in the scientific method, is my primary evidence for success. Resources are very limited at my institution, so here are a couple of suggestions that work well. Borrow equipmentâfrom other universities, from consulting companies, from colleagues. Simplify analysesâmany interesting conclusions can be drawn from simply pH, conductivity, and temperature data. But, there are also relatively inexpensive test kits on the market that are sufficient for class purposes (ex. LaMotte urban water test kit ~$30). Description Everyone will have different class sizes, student preparation levels, and goals when attempting an exercise like this, so I will provide general information, which others can modify to meet their needs. Below I briefly outline the steps I take the students through during the project and highlight ideas for improving success for the targeted groups. Form groupsâdepending on class size, 2-4 students per group (I try to ensure the groups are balanced based on skills and student interests) Choose topicâI usually provide a list of possible topics and have students adapt a topic from the list that interests them. Students require a lot of guidance at this stage to assure selection of a manageable topic for a quarter-long project. This is the most important step - guiding students into a topic they are passionate about and where they can be successful is key. Students usually have no shortage of questions they want to answer about water in an urban environment! Since most of the students have spent their whole lives in an urban situation, they are deeply passionate about these issues. Research literatureâstudents perform a background search for previous work on their topic to help guide them. I provide a laboratory session on how to search the library and databases for related information, as well as provide a list of recommended journals and websites. In addition, students locate supporting data (discharge, well levels, precipitation) Plan studyâwe discuss study design, sample types, sampling location, frequency. During this phase, students use maps, study weather patterns, and determine site accessibility. Collect dataâwe set aside lab periods for collecting data together. These are the sessions where you should be prepared to answer all sort of questions. Once the students begin implementing their study, many new questions come up. Analyze and interpret resultsâmultiple lab periods are used to analyze data; student data are the basis of the remainder of labs. Techniques discussed are applied to their group projects. Prese

  20. Hydrogeologic framework and groundwater/surface-water interactions of the upper Yakima River Basin, Kittitas County, central Washington

    USGS Publications Warehouse

    Gendaszek, Andrew S.; Ely, D. Matthew; Hinkle, Stephen R.; Kahle, Sue C.; Welch, Wendy B.

    2014-01-01

    The hydrogeology, hydrology, and geochemistry of groundwater and surface water in the upper (western) 860 square miles of the Yakima River Basin in Kittitas County, Washington, were studied to evaluate the groundwater-flow system, occurrence and availability of groundwater, and the extent of groundwater/surface-water interactions. The study area ranged in altitude from 7,960 feet in its headwaters in the Cascade Range to 1,730 feet at the confluence of the Yakima River with Swauk Creek. A west-to-east precipitation gradient exists in the basin with the western, high-altitude headwaters of the basin receiving more than 100 inches of precipitation per year and the eastern, low-altitude part of the basin receiving about 20 inches of precipitation per year. From the early 20th century onward, reservoirs in the upper part of the basin (for example, Keechelus, Kachess, and Cle Elum Lakes) have been managed to store snowmelt for irrigation in the greater Yakima River Basin. Canals transport water from these reservoirs for irrigation in the study area; additional water use is met through groundwater withdrawals from wells and surface-water withdrawals from streams and rivers. Estimated groundwater use for domestic, commercial, and irrigation purposes is reported for the study area. A complex assemblage of sedimentary, metamorphic, and igneous bedrock underlies the study area. In a structural basin in the southeastern part of the study area, the bedrock is overlain by unconsolidated sediments of glacial and alluvial origin. Rocks and sediments were grouped into six hydrogeologic units based on their lithologic and hydraulic characteristics. A map of their extent was developed from previous geologic mapping and lithostratigraphic information from drillers’ logs. Water flows through interstitial space in unconsolidated sediments, but largely flows through fractures and other sources of secondary porosity in bedrock. Generalized groundwater-flow directions within the unconfined part of the aquifers in unconsolidated sediments indicate generalized groundwater movement toward the Yakima River and its tributaries and the outlet of the study area. Groundwater movement through fractures within the bedrock aquifers is complex and varies over spatial scales depending on the architecture of the fracture-flow system and its hydraulic properties. The complexity of the fracturedbedrock groundwater-flow system is supported by a wide range of groundwater ages determined from geochemical analyses of carbon-14, sulfur hexafluoride, and tritium in groundwater. These geochemical data also indicate that the shallow groundwater system is actively flushing with young, isotopically heavy groundwater, but isotopicallylight, Pleistocene-age groundwater with a geochemicallyevolved composition occurs at depth within the fracturedbedrock aquifers of upper Kittitas County. An eastward depletion of stable isotopes in groundwater is consistent with hydrologically separate subbasins. This suggests that groundwater that recharges in one subbasin is not generally available for withdrawal or discharge into surface-water features within other subbasins. Water budget components were calculated for 11 subbasins using a watershed model and varied based on the climate, land uses, and geology of the subbasin. Synoptic streamflow measurements made in August 2011 indicate that groundwater discharges into several tributaries of the Yakima River with several losses of streamflow measured where the streams exit bedrock uplands and flow over unconsolidated sediments. Profiles of stream temperature during late summer suggest cool groundwater inflow over discrete sections of streams. This groundwater/surfacewater connection is further supported by the stable-isotope composition of stream water, which reflects the local stableisotope composition of groundwater measured at some wells and springs. Collectively, these hydrogeologic, hydrologic, and geochemical data support a framework for evaluating the potential effects of future groundwater appropriations on senior surface-water

  1. A Conceptual Model of Coupled Biogeochemical and Hydrogeological Processes Affected by In Situ Cr(VI) Bioreduction in Groundwater at Hanford 100H Site

    Microsoft Academic Search

    B. Faybishenko; P. E. Long; T. C. Hazen; S. S. Hubbard; K. H. Williams; J. E. Peterson; J. Chen; E. V. Volkova; D. R. Newcomer; C. T. Resch; K. Cantrell; M. S. Conrad; E. L. Brodie; D. C. Joyner; S. E. Borglin; R. C. Chakraborty

    2007-01-01

    The overall objective of this presentation is to demonstrate a conceptual multiscale, multidomain model of coupling of biogeochemical and hydrogeological processes during bioremediation of Cr(VI) contaminated groundwater at Hanford 100H site. A slow release polylactate, Hydrogen Release Compound (HRCTM), was injected in Hanford sediments to stimulate immobilization of Cr(VI). The HRC injection induced a 2-order-of- magnitude increase in biomass and

  2. Review of buried crystalline rocks of eastern United States in selected hydrogeologic environments potentially suitable for isolating high-level radioactive wastes

    USGS Publications Warehouse

    Davis, R.W.

    1984-01-01

    Among the concepts suggested for the deep disposal of high-level radioactive wastes from nuclear power reactors is the excavation of a repository in suitable crystalline rocks overlain by a thick sequence of sedimentary strata in a hydrogeologic environment that would effectively impede waste transport. To determine the occurrence of such environments in the Eastern United States, a review was made of available sources of published or unpublished information, using the following hydrogeologic criteria: (1) the top of the crystalline basement rock is 1,000 to 4,000 feet below land surface; (2) the crystalline rock is overlain by sedimentary rock whose lowermost part, at least, contains groundwater with a dissolved-solids concentration of 10,000 milligrams per liter or more; (3) shale and or clay confining beds overlie the saline-water aquifer; and (4) the flow system in the saline-water aquifer is known or determinable from presently available data. All of these hydrogeologic conditions occur in two general areas: (1) parts of Indiana, Ohio, and Kentucky, underlain by part of the geologic structure known as the Cincinnati arch, and (2) parts of the Atlantic Coastal Plain from Georgia to New Jersey. (USGS)

  3. 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.

  4. Geologic and hydrogeologic framework of the Espanola Basin -- proceedings of the 4th annual Espanola Basin Workshop, Santa Fe, New Mexico, March 1-3, 2005

    USGS Publications Warehouse

    McKinney, Kevin C.

    2005-01-01

    This report presents abstracts of technical studies that pertain to the hydrogeologic framework of the Espa?ola basin, a major subbasin of the Cenozoic Rio Grande rift. Sediments and interbedded volcanic rocks that fill the Espa?ola basin comprise an aquifer system that is an important source of water for many residents of the basin, including people in the cities of Santa Fe, Espa?ola, and Los Alamos as well as Native Americans in eleven Pueblos. The abstracts describe results of technical studies that were presented either as poster exhibits or oral presentations at the forth-annual Espa?ola basin workshop, held March 1-2 of 2005 in Santa Fe, New Mexico. The principal goal of this workshop was to share information about ongoing studies. The Espa?ola basin workshop was hosted by the Espa?ola basin technical advisory group (EBTAG) and sponsored by the U.S. Geological Survey, the New Mexico Bureau of Geology and Mineral Resources, and both the Water Research Technical Assistance Office and the Groundwater Protection Program of Los Alamos National Laboratory. Abstracts in this report have been grouped into six information themes: Basic Water Data, Water Quality and Water Chemistry, Water Balance and Stream/Aquifer Interaction, Data Integration and Hydrologic Model Testing, Three-Dimensional Hydrogeological Architecture, and Geologic Framework. Taken together, the abstracts in this report provide a view of the current status of hydrogeologic research within the Espa?ola basin.

  5. Application of statistical approaches to analyze geological, geotechnical and hydrogeological data at a fractured-rock mine site in Northern Canada

    NASA Astrophysics Data System (ADS)

    Mayer, J. M.; Allen, D. M.; Gibson, H. D.; Mackie, D. C.

    2014-05-01

    Mine site characterization often results in the acquisition of geological, geotechnical and hydrogeological data sets that are used in the mine design process but are rarely co-evaluated. For a study site in northern Canada, bivariate and multivariate (hierarchical) statistical techniques are used to evaluate empirical hydraulic conductivity estimation methods based on traditional rock mass characterisation schemes, as well as to assess the regional hydrogeological conceptual model. Bivariate techniques demonstrate that standard geotechnical measures of fracturing are poor indicators of the hydraulic potential of a rock mass at the study site. Additionally, rock-mass-permeability schemes which rely on these measures are shown to be poor predictors of hydraulic conductivity in untested areas. Multivariate techniques employing hierarchical cluster analysis of both geotechnical and geological data sets are able to identify general trends in the data. Specifically, the geological cluster analysis demonstrated spatial relationship between intrusive contacts and increased hydraulic conductivity. This suggests promise in the use of clustering methods in identifying new trends during the early stages of hydrogeological characterization.

  6. 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.

  7. 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).

  8. 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.

  9. 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.

  10. Hydrogeology and water quality in the Snake River alluvial aquifer at Jackson Hole Airport, Jackson, Wyoming, September 2008-June 2009

    USGS Publications Warehouse

    Wright, Peter R.

    2010-01-01

    The hydrogeology and water quality of the Snake River alluvial aquifer, at the Jackson Hole Airport in northwest Wyoming, was studied by the U.S. Geological Survey in cooperation with the Jackson Hole Airport Board and the Teton Conservation District during September 2008-June 2009. Hydrogeologic conditions were characterized using data collected from 14 Jackson Hole Airport wells. Groundwater levels are summarized in this report and the direction of groundwater flow, hydraulic gradients, and estimated groundwater velocity rates in the Snake River alluvial aquifer underlying the study area are presented. Analytical results of chemical, dissolved gas, and stable isotopes are presented and summarized. Seasonally, the water table at Jackson Hole Airport was lowest in early spring and reached its peak in July, with an increase of 12 to 14 feet between April and July 2009. Groundwater flow was predominantly horizontal but had the hydraulic potential for downward flow. The direction of groundwater flow was from the northeast to the west-southwest. Horizontal groundwater velocities within the Snake River alluvial aquifer at the airport were estimated to be about 26 to 66 feet per day. This indicates that the traveltime from the farthest upgradient well to the farthest downgradient well was approximately 53 to 138 days. This estimate only describes the movement of groundwater because some solutes may move at a rate much slower than groundwater flow through the aquifer. The quality of the water in the alluvial aquifer generally was considered good. The alluvial aquifer was a fresh, hard to very hard, calcium carbonate type water. No constituents were detected at concentrations exceeding U.S. Environmental Protection Agency Maximum Contaminant Levels, and no anthropogenic compounds were detected at concentrations greater than laboratory reporting levels. The quality of groundwater in the alluvial aquifer generally was suitable for domestic and other uses; however, dissolved iron and manganese were detected at concentrations exceeding the U.S. Environmental Protection Agency Secondary Maximum Contaminant Levels for drinking water in two monitoring wells. These secondary standards are esthetic guidelines only and are nonenforceable. Iron and manganese are likely both natural components of the geologic materials in the area and may have become mobilized in the aquifer due to reduction/oxidation (redox) processes. Additionally, measurements of dissolved-oxygen concentrations and analyses of major ions and nutrients indicate reducing conditions exist at two of the seven wells sampled. Reducing conditions in an otherwise oxic aquifer system are indicative of an upgradient or in-situ source of organic carbon. The nature of the source of organic carbon at the airport could not be determined. View report for unabridged abstract.

  11. 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.

  12. A hydrogeologic approach to identify land uses that overlie ground-water flow paths, Broward County, Florida

    USGS Publications Warehouse

    Sonenshein, R.S.

    1995-01-01

    A hydrogeologic approach that integrates the use of hydrogeologic and spatial tools aids in the identification of land uses that overlie ground- water flow paths and permits a better understanding of ground-water flow systems. A mathematical model was used to simulate the ground-water flow system in Broward County, particle-tracking software was used to determine flow paths leading to the monitor wells in Broward County, and a Geographic Information System was used to identify which land uses overlie the flow paths. A procedure using a geographic information system to evaluate the output from a ground-water flow model has been documented. The ground-water flow model was used to represent steady-state conditions during selected wet- and dry-season months, and an advective flow particle- tracking program was used to simulate the direction of ground-water flow in the aquifer system. Digital spatial data layers were created from the particle pathlines that lead to the vicinity of the open interval of selected wells in the Broward County ground-water quality monitoring network. Buffer zone data layers were created, surrounding the particle pathlines to represent the area of contribution to the water sampled from the monitor wells. Spatial data layers, combined with a land-use data layer, were used to identify the land uses that overlie the ground-water flow paths leading to the monitor wells. The simulation analysis was performed on five Broward County wells with different hydraulic parameters to determine the source of ground-water stress, determine selected particle pathlines, and identify land use in buffer zones in the vicinity of the wells. The flow paths that lead to the grid cells containing wells G-2355, G-2373, and G-2373A did not vary between the wet- and dry-season conditions. Changes in the area of contribution for wells G-2345X and G-2369 were attributed to variations in rainfall patterns, well-field pumpage, and surface-water management practices. Additionally, using a different open interval at a site, such as for wells G-2373 and G-2373A, can result in a very different area that overlies the flow path leading to the monitor well.

  13. Hydrogeologic Framework of the Upper Santa Cruz Basin (Arizona and Sonora) using Well Logs, Geologic Mapping, Gravity, Magnetics, and Electromagnetics

    NASA Astrophysics Data System (ADS)

    Callegary, J. B.; Page, W. R.; Megdal, S.; Gray, F.; Scott, C. A.; Berry, M.; Rangel, M.; Oroz Ramos, L.; Menges, C. M.; Jones, A.

    2011-12-01

    In 2006, the U.S. Congress passed the U.S.-Mexico Transboundary Aquifer Assessment Act which provides a framework for study of aquifers shared by the United States and Mexico. The aquifer of the Upper Santa Cruz Basin was chosen as one of four priority aquifers for several reasons, including water scarcity, a population greater than 300,000, groundwater as the sole source of water for human use, and a riparian corridor that is of regional significance for migratory birds and other animals. Several new mines are also being proposed for this area which may affect water quality and availability. To date, a number of studies have been carried out by a binational team composed of the U.S. Geological Survey, the Mexican National Water Commission, and the Universities of Arizona and Sonora. Construction of a cross-border hydrogeologic framework model of the basin between Amado, Arizona and its southern boundary in Sonora is currently a high priority. The relatively narrow Santa Cruz valley is a structural basin that did not experience the same degree of late Cenozoic lateral extension and consequent deepening as found in other basin-and-range alluvial basins, such as the Tucson basin, where basin depth exceeds 3000 meters. This implies that storage may be much less than that found in other basin-and-range aquifers. To investigate the geometry of the basin and facies changes within the alluvium, a database of over one thousand well logs has been developed, geologic mapping and transient electromagnetic (TEM) surveys have been carried out, and information from previous electromagnetic, magnetic, and gravity studies is being incorporated into the hydrogeologic framework. Initial geophysical surveys and analyses have focused on the portion of the basin west of Nogales, Arizona, because it supplies approximately 50% of that city's water. Previous gravity and magnetic modeling indicate that this area is a narrow, fault-controlled half graben. Preliminary modeling of airborne and ground-based transient electromagnetic surveys corroborates earlier conclusions from the gravity modeling that depth to bedrock is greater than 500 meters in some locations. Results from other portions of the study area including Mexico are still being evaluated and incorporated into the three-dimensional hydrologic framework which will ultimately be used to construct a groundwater flow model.

  14. 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.

  15. Hydrogeologic performance assessment analysis of the commercial low-level radioactive waste disposal facility near West Valley, New York

    SciTech Connect

    Bergeron, M.P.; Smoot, J.L.; Kemner, M.L.; Cronin, W.E. (Pacific Northwest Lab., Richland, WA (USA))

    1991-06-01

    A hydrogeologic performance assessment of the commercial low-level waste site near West Valley, New York, was performed for two pathways: a shallow lateral pathway where trench water can potentially migrate laterally through fractured and weathered till to nearby streams and a deep vertical pathway where leachate can migrate downward through unweathered till and laterally offsite in a lacustrine unit. Along the shallow pathway, little physical site evidence is available to indicate what the degree of lateral migration can be. Past modeling showed that overflowing trench water would migrate laterally some distance before migrating downward into the unweathered till. If water did reach a nearby stream, calculations show that decay, adsorption, and stream dilution would reduce leachate concentration to acceptable levels. Within the deep pathway, tritium and {sup 14}C were the only radionuclides released in any significant concentrations. Predicted tritium levels are well below regulatory limits; however, predicted peak {sup 14}C concentrations, while meeting the 25 mrem/yr limit using the drinking-water-only exposure scenario, exceed the limit for the full garden scenario. Site information on {sup 14}C release rates and geochemical behavior has considerable uncertainty and would need to be more fully evaluated in a licensing situation. 58 refs., 32 figs., 12 tabs.

  16. 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.

  17. Hydrogeologic data update for the stratified-drift aquifer in the Sprout and Fishkill Creek valleys, Dutchess County, New York

    USGS Publications Warehouse

    Reynolds, Richard J.; Calef, F.J., III

    2011-01-01

    The hydrogeology of the stratified-drift aquifer in the Sprout Creek and Fishkill Creek valleys in southern Dutchess County, New York, previously investigated by the U.S. Geological Survey (USGS) in 1982, was updated through the use of new well data made available through the New York State Department of Environmental Conservation's Water Well Program. Additional well data related to U.S. Environmental Protection Agency (USEPA) remedial investigations of two groundwater contamination sites near the villages of Hopewell Junction and Shenandoah, New York, were also used in this study. The boundary of the stratified-drift aquifer described in a previous USGS report was extended slightly eastward and southward to include adjacent tributary valleys and the USEPA groundwater contamination site at Shenandoah, New York. The updated report consists of maps showing well locations, surficial geology, altitude of the water table, and saturated thickness of the aquifer. Geographic information system coverages of these four maps were created as part of the update process.

  18. Hydrogeologic framework of the uppermost principal aquifer systems in the Williston and Powder River structural basins, United States and Canada

    USGS Publications Warehouse

    Thamke, Joanna N.; LeCain, Gary D.; Ryter, Derek W.; Sando, Roy; Long, Andrew J.

    2014-01-01

    Analysis of about 300 electric (resistivity) and lithologic logs in the Williston structural basin and numerous existing publications for the Powder River structural basin were used to develop a three-dimensional hydrogeologic framework for both basins. Interpolated thicknesses of the glacial deposits, the lower Tertiary aquifer system, and the Upper Cretaceous aquifer system in the Williston structural basin are less than about 750; 2,250; and 1,050 ft, respectively. Interpolated thicknesses of the lower Tertiary aquifer system and the Upper Cretaceous aquifer system in the Powder River structural basin are less than about 7,180 and 5,070 ft, respectively. Interpolated horizontal hydraulic conductivity values for the Williston structural basin were as much as 25 feet per day (ft/d) in the glacial deposits and had smaller ranges in the lower Tertiary aquifer system (0.01–9.8 ft/d) and in the Upper Cretaceous aquifer system (0.06–5.5 ft/d). In the Powder River structural basin, the lower Tertiary aqu

  19. Hydrogeological modeling constraints provided by geophysical and geochemical mapping of a chlorinated ethenes plume in northern France

    NASA Astrophysics Data System (ADS)

    Razafindratsima, Stephen; Guérin, Roger; Bendjoudi, Hocine; de Marsily, Ghislain

    2014-09-01

    A methodological approach is described which combines geophysical and geochemical data to delineate the extent of a chlorinated ethenes plume in northern France; the methodology was used to calibrate a hydrogeological model of the contaminants' migration and degradation. The existence of strong reducing conditions in some parts of the aquifer is first determined by measuring in situ the redox potential and dissolved oxygen, dissolved ferrous iron and chloride concentrations. Electrical resistivity imaging and electromagnetic mapping, using the Slingram method, are then used to determine the shape of the pollutant plume. A decreasing empirical exponential relation between measured chloride concentrations in the water and aquifer electrical resistivity is observed; the resistivity formation factor calculated at a few points also shows a major contribution of chloride concentration in the resistivity of the saturated porous medium. MODFLOW software and MT3D99 first-order parent-daughter chain reaction and the RT3D aerobic-anaerobic model for tetrachloroethene (PCE)/trichloroethene (TCE) dechlorination are finally used for a first attempt at modeling the degradation of the chlorinated ethenes. After calibration, the distribution of the chlorinated ethenes and their degradation products simulated with the model approximately reflects the mean measured values in the observation wells, confirming the data-derived image of the plume.

  20. Hydrogeology and flow of water in a sand and gravel aquifer contaminated by wood-preserving compounds, Pensacola, Florida

    USGS Publications Warehouse

    Franks, B.J.

    1988-01-01

    The sand and gravel aquifer in southern Escambia County, Florida , is a typical surficial aquifer composed of quartz sands and gravels interbedded locally with silts and clays. Problems of groundwater contamination from leaking surface impoundments are common in surficial aquifers and are a subject of increasing concern and attention. A potentially widespread contamination problem involves organic chemicals from wood-preserving processes. Because creosote is the most extensively used industrial preservative in the United States, an abandoned wood-treatment plant near Pensacola was chosen for investigation. This report describes the hydrogeology and groundwater flow system of the sand and gravel aquifer near the plant. A three-dimensional simulation of groundwater flow in the aquifer was evaluated under steady-state conditions. The model was calibrated on the basis of observed water levels from January 1986. Calibration criteria included reproducing all water levels within the accuracy of the data (one-half contour interval in most cases). Sensitivity analysis showed that the simulations were most sensitive to recharge and vertical leakance of the confining units between layers 1 and 2, and relatively insensitive to changes in hydraulic conductivity and transmissivity and to other changes in vertical leakance. Applications of the results of the calibrated flow model in evaluation of solute transport may require further discretization of the contaminated area, including more sublayers, than were needed for calibration of the groundwater flow system itself. (USGS)

  1. Hydrostratigraphy and hydrogeology of the western part of Maira area, Khyber Pakhtunkhwa, Pakistan: a case study by using electrical resistivity.

    PubMed

    Farid, Asam; Jadoon, Khanzaib; Akhter, Gulraiz; Iqbal, Muhammad Asim

    2013-03-01

    Hydrostratigraphy and hydrogeology of the Maira vicinity is important for the characterization of aquifer system and developing numerical groundwater flow models to predict the future availability of the water resource. Conventionally, the aquifer parameters are obtained by the analysis of pumping tests data which provide limited spatial information and turn out to be costly and time consuming. Vertical electrical soundings and pump testing of boreholes were conducted to delineate the aquifer system at the western part of the Maira area, Khyber Pakhtun Khwa, Pakistan. Aquifer lithology in the eastern part of the study area is dominated by coarse sand and gravel whereas the western part is characterized by fine sand. An attempt has been made to estimate the hydraulic conductivity of the aquifer system by establishing a relationship between the pumping test results and vertical electrical soundings by using regression technique. The relationship is applied to the area along the resistivity profiles where boreholes are not drilled. Our findings show a good match between pumped hydraulic conductivity and estimated hydraulic conductivity. In case of sparse borehole data, regression technique is useful in estimating hydraulic properties for aquifers with varying lithology. PMID:22736209

  2. 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.

  3. Quantitative modeling and three-dimensional visualization of the petroleum hydrogeology of the Cooper & Eromanga Basins, Australia

    SciTech Connect

    Person, M.; Morin, P. [Univ. of Minnestoa, Minneapolis, MN (United States); Toupin, D. [Univ. of New Hampshire, Durham, NH (United States); Eadington, P. [CSIRO, North Ryde, NSW (Australia)

    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.

  4. Quantitative modeling and three-dimensional visualization of the petroleum hydrogeology of the Cooper Eromanga Basins, Australia

    SciTech Connect

    Person, M.; Morin, P. (Univ. of Minnestoa, Minneapolis, MN (United States)); Toupin, D. (Univ. of New Hampshire, Durham, NH (United States)); Eadington, P. (CSIRO, North Ryde, NSW (Australia))

    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.

  5. 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)

  6. The impact of groundwater on the excavation of tunnels in two different hydrogeological settings in central Italy

    NASA Astrophysics Data System (ADS)

    Chiocchini, Ugo; Castaldi, Fabio

    2011-05-01

    To double the capacity of the Orte-Falconara railway line (central Italy), the Santa Croce tunnel was constructed (1985-1995), which runs between the Nera Montoro and Narni stations. In the same period, to double the capacity of the Ancona-Bari railway line, the Moro, Cintioni, S. Giovanni and Diavolo tunnels were constructed between the Ortona and Casalbordino stations. The high likelihood of intercepting a significant volume of groundwater in calcareous rocks of the Santa Croce tunnel led to a shift in the layout of the tunnel, which allowed construction of the tunnel by more rapid and less expensive means. Groundwater along the Moro tunnel layout, in a sandy aquifer, has been drained by the excavation of a preliminary tunnel, which allowed a discharge of up to 0.080 m3/s. In the S. Giovanni and Diavolo tunnels, a particular hydrogeological setting was found to exist in the form of lens-shaped bodies of fine grey sand-and-silt aquitards intercalated between the bottom muddy-sandy deposits (very low permeability) and the sandy aquifer; this caused sudden groundwater inflow and tunnel collapse. The S. Giovanni tunnnel, excavation was completed using the HydroShield system, whereas in the Diavolo tunnel, a well-point system was adopted, which avoided any environmental hazards.

  7. 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.

  8. 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.

  9. 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).

  10. 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

  11. Hydrogeological framework and estimation of aquifer hydraulic parameters using geoelectrical data: a case study from West Iran

    NASA Astrophysics Data System (ADS)

    Tizro, Abduulah Taheri; Voudouris, Kostantanous S.; Salehzade, Mortaza; Mashayekhi, Hassan

    2010-06-01

    Detailed local geological, geophysical, and hydrogeological investigations were carried out for the alluvial aquifer in the Kangavar basin, West Iran to delineate the architecture of different subsurface geological horizons using lithologs and generated vertical electrical sounding (VES) data. An attempt has also been made to estimate aquifer transmissivity from resistivity data. Forty VESs were recorded with the Schlumberger electrode configuration in the study area; 28 of these were selected for evaluation. The maximum current electrode spacing was 400-500 m. The data obtained were interpreted by computer iterative modeling with curve matching for calibration purposes. In order to ascertain the subsurface geological framework, the general distribution of resistivity responses of the geological formations was obtained and geoelectrical sections along a number of lines were prepared. Probable aquifer horizons from these sections were identified. The transmissivity of the unconfined aquifer was computed by determining the Dar-Zarrouk parameters (longitudinal unit conductance and transverse unit resistance) and were compared with the actual field transmissivity. The results showed a direct relation between aquifer transmissivity and modified transverse resistance.

  12. Salinity sources of Kefar Uriya wells in the Judea Group aquifer of Israel. Part 1—conceptual hydrogeological model

    NASA Astrophysics Data System (ADS)

    Avisar, D.; Rosenthal, E.; Flexer, A.; Shulman, H.; Ben-Avraham, Z.; Guttman, J.

    2003-01-01

    In the Yarkon-Taninim groundwater basin, the karstic Judea Group aquifer contains groundwater of high quality. However, in the western wells of the Kefar Uriya area located in the foothills of the Judea Mountains, brackish groundwater was locally encountered. The salinity of this water is caused presumably by two end members designated as the 'Hazerim' and 'Lakhish' water types. The Hazerim type represents surface water percolating through a highly fractured thin chalky limestone formation overlying the Judea Group aquifer. The salinity of the water derives conjointly from several sources such as leachates from rendzina and grumosols, dissolution of caliche crusts which contain evaporites and of rock debris from the surrounding formations. This surface water percolates downwards into the aquifer through a funnel- or chimney-like mechanism. This local salinization mechanism supercedes another regional process caused by the Lakhish waters. These are essentially diluted brines originating from deep formations in the western parts of the Coastal Plain. The study results show that salinization is not caused by the thick chalky beds of the Senonian Mt Scopus Group overlying the Judea Group aquifer, as traditionally considered but prevalently by aqueous leachates from soils and rock debris. The conceptual qualitative hydrogeological model of the salinization as demonstrated in this study, is supported by a quantitative hydrological model presented in another paper in this volume.

  13. Morphotectonic Methods To Infer Groundwater Flow Under Conditions Of Scarce Hydrogeological Data - The Case Of Northern Arava, Israel

    NASA Astrophysics Data System (ADS)

    Golts, S.; Rosenthal, E.

    1992-01-01

    In areas characterized by flat and weakly incised relief built of young and lithologically uniform sediments, structural and tectonic maps are often nonexistent or are of no great avail. Under such conditions, the regional morphotectonic analysis of the study area may be a useful method to produce the required basic hydrogeological information. The method consists of two basic steps: (1) definition of stream orders and, (2) the preparation of isobase maps. In the research of Quaternary geology, isobase surface analysis is regarded as a means for identifying young tectonic processes. The morphotectonic map is the final derivative of isobase maps. It portrays the basic lineaments or dislocation lines derived by analyzing deviations in the directions of isobase lines, of their spreading or compression, and of deviations between axes of valleys. The morphotectonic map presented in this paper portrays several major morphostructural units within the Arava graben, in the area between the Dead Sea and Nahal Paran. When combined with hydrological data from boreholes, it facilitates elucidation of groundwater flow paths and salinization focci controlled by structural elements.

  14. Hydrogeology and results of aquifer tests in the vicinity of a hazardous-waste disposal site near Byron, Illinois

    USGS Publications Warehouse

    Kay, Robert T.; Olson, David N.; Ryan, Barbara J.

    1989-01-01

    The U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, conducted an investigation of a Superfund Site near Byron, Illinois. The purpose of the investigation was to determine the hydrogeologic properties of the Galena-Platteville and St. Peter aquifers, the primary water-supply aquifers for domestic supply in the area. The Galena and Platteville Groups and older St. Peter Sandstone are separated by the Harmony Hill Shale Member of the Glenwood Formation. The Harmony Hill Shale Member is a semiconfining unit. Groundwater flow in the study area is from the site northwestward to the Rock River. Movement of groundwater in the dolomites is mainly through joints, fractures, and solution openings. Analysis of the Galena-Platteville aquifer-test data indicates that the calculated aquifer transmissivity ranges from 490 to 670 sq ft/day, and the calculated specific yield ranges from 0.017 to 0.140. Aquifer test data also indicate that the Galena-Platteville aquifer is heterogeneous and anisotropic. Analysis of the St. Peter aquifer-test data indicates that the calculated transmissivity of the aquifer ranges from 1,200 to 1 ,305 sq ft/day, storativity ranges from 0.000528 to 0.00128, horizontal hydraulic conductivity ranges from 2.9 to 3.1 ft/day, and leakage through the Harmony Hill Shale Member ranges from .000123 to .000217 ft/day/ft. (USGS)

  15. 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.

  16. 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.

  17. Geologic and hydrogeologic characteristics of the Ogallala Formation and White River Group, Belvoir Ranch near Cheyenne, Laramie County, Wyoming

    USGS Publications Warehouse

    Bartos, Timothy T.; Diehl, Sharon F.; Hallberg, Laura L.; Webster, Daniel M.

    2014-01-01

    The geologic and hydrogeologic characteristics of Tertiary lithostratigraphic units (Ogallala Formation and White River Group) that typically compose or underlie the High Plains aquifer system in southeastern Wyoming were described physically and chemically, and evaluated at a location on the Belvoir Ranch in Laramie County, Wyoming. On the basis of this characterization and evaluation, three Tertiary lithostratigraphic units were identified using physical and chemical characteristics determined during this study and previous studies, and these three units were determined to be correlative with three identified hydrogeologic units composing the groundwater system at the study site—a high-yielding aquifer composed of the entire saturated thickness of the heterogeneous and coarse-grained fluvial sediments assigned to the Ogallala Formation (Ogallala aquifer); an underlying confining unit composed primarily of very fine-grained volcaniclastic sediments and mudrocks assigned to the Brule Formation of the White River Group and some additional underlying sediments that belong to either the Brule or Chadron Formation, or both (Brule confining unit); and an underlying low-yielding aquifer composed primarily of poorly sorted fluvial sediments assigned to the Chadron Formation of the White River Group (Chadron aquifer). Despite widely varying sediment heterogeneity and consolidation, some limited hydraulic connection throughout the full vertical extent of the Ogallala aquifer was indicated but not conclusively proven by interpretation of similar chemical and isotopic characteristics, modern apparent groundwater ages, and similar hydraulic-head responses measured continuously in two Ogallala aquifer monitoring wells installed for this study at two different widely separated (83 feet) depth intervals. Additional work beyond the scope of this study, such as aquifer tests, would be required to conclusively determine hydraulic connection within the Ogallala aquifer. Groundwater levels (hydraulic heads) measured continuously using water-level recorders in both monitoring wells completed in the Ogallala aquifer showed a consistent strong upward vertical gradient in the Ogallala aquifer, indicating the potential for water to move from deeper to shallower parts of the aquifer, regardless of the time of year and the presumed effects of pumping of public-supply and industrial wells in the area. Continuous measurement of groundwater levels in the shallowest monitoring well, installed near the water table, and examination of subsequently constructed water-level hydrographs indicated substantial groundwater recharge is likely during the spring of 2009 and 2010 from the ephemeral stream (Lone Tree Creek) located adjacent to the study site that flows primarily in response to spring snowmelt from the adjacent Laramie Mountains and surface runoff from precipitation events. Using the water-table fluctuation method, groundwater recharge was estimated to be about 13 inches for the period beginning in early October 2009 and ending in late June 2010, and about 4 inches for the period beginning in March 2011 and ending in early July 2011. Comparison of previously measured groundwater levels (hydraulic heads) and groundwater-quality characteristics in nearby monitoring wells completed in the Chadron aquifer with those measured in the two monitoring wells installed for this study in the Ogallala aquifer, combined with detailed lithologic characterization, strongly indicated the Brule confining unit hydraulically confines and isolates the Chadron aquifer from the overlying Ogallala aquifer, thus likely limiting hydraulic connection between the two units. Consequently, because of the impermeable nature of the Brule confining unit and resulting hydraulic separation of the Ogallala and Chadron aquifers, and compared with local and regional hydrostratigraphic definitions of the High Plains aquifer system, the groundwater system in Tertiary lithostratigraphic units overlying the Upper Cretaceous Lance Formation at the location studied on the Belvoir Ranch was

  18. A remote sensing approach to characterize the hydrogeology of mountainous areas: Application to the Quito Aquifer System (QAS), Ecuador

    NASA Astrophysics Data System (ADS)

    Rios-Sanchez, Miriam

    Climate change, intensive use, and population growth are threatening the availability of water resources. New sources of water, better knowledge of existing ones, and improved water management strategies are of paramount importance. Ground water is often considered as primary water source due to its advantages in terms of quantity, spatial distribution, and natural quality. Remote sensing techniques afford scientists a unique opportunity to characterize landscapes in order to assess groundwater resources, particularly in tectonically influenced areas. Aquifers in volcanic basins are considered the most productive aquifers in Latin America. Although topography is considered the primary driving force for groundwater flows in mountainous terrains, tectonic activity increases the complexity of these groundwater systems by altering the integrity of sedimentary rock units and the overlying drainage networks. Structural controls affect the primary hydraulic properties of the rock formations by developing barriers to flow in some cases and zones of preferential infiltration and subterranean in others. The study area focuses on the Quito Aquifer System (QAS) in Ecuador. The characterization of the hydrogeology started with a lineament analysis based on a combined remote sensing and digital terrain analysis approach. The application of classical tools for regional hydrogeological evaluation and shallow geophysical methods were useful to evaluate the impact of faulting and fracturing on the aquifer system. Given the spatial extension of the area and the complexity of the system, two levels of analysis were applied in this study. At the regional level, a lineament map was created for the QAS. Relationships between fractures, faults and lineaments and the configuration of the groundwater flow on the QAS were determined. At the local level, on the Plateaus region of the QAS, a detailed lineament map was obtained by using high-spatial-resolution satellite imagery and aspect map derived from a digital elevation model (DEM). This map was complemented by the analysis of morphotectonic indicators and shallow geophysics that characterize fracture patterns. The development of the groundwater flow system was studied, drawing upon data pertaining to the aquifer system physical characteristics and topography. Hydrochemistry was used to ascertain the groundwater evolution and verify the correspondence of the flow patterns proposed in the flow system analysis. Isotopic analysis was employed to verify the origin of groundwater. The results of this study show that tectonism plays a very important role for the hydrology of the QAS. The results also demonstrate that faults influence a great deal of the topographic characteristics of the QAS and subsequently the configuration of the groundwater flow. Moreover, for the Plateaus region, the results demonstrate that the aquifer flow systems are affected by secondary porosity. This is a new conceptualization of the functioning of the aquifers on the QAS that will significantly contribute to the development of better strategies for the management of this important water resource.

  19. 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.

  20. 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

  1. 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. [CSIRO, North Ryde (Australia)] [and others

    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.

  2. Hydrogeology and analysis of ground-water withdrawal in the Mendenhall-D'Lo area, Simpson County, Mississippi

    USGS Publications Warehouse

    Strom, E.W.; Oakley, W.T.

    1995-01-01

    The cities of Mendenhall and D'Lo, located in Simpson County, rely on ground water for their public supply and industrial needs. Most of the ground water comes from an aquifer of Miocene age. A study began in 1991 to describe the hydrogeology, analyze effects of ground-water withdrawal by making a drawdown map, and estimate the effects increased ground-water withdrawal might have on water levels in the Miocene age aquifer in the Mendenhall-D'Lo area. The most significant withdrawals of ground water in the study area are from 10 wells screened in the lower sand of the Catahoula Formation of Miocene age. Analysis of the effect of withdrawals from the 10 wells was made using the Theis non- equilibrium equation and applying the principle of superposition. Analysis of 1994 conditions was based on the pumpage history and aquifer properties deter- mined for each well. The drawdown surface resulting from the analysis indicates three general cones of depression. One cone is in the northwestern D'Lo area, one in the south-central Mendenhall area, and one about 1-1/2 miles east of Mendenhall. Calculated drawdown ranges from 21 to 47 feet. Potential drawdown-surface maps were made for 10 years and 20 years beyond 1994 using a constant pumpage. The map made for 10 years beyond 1994 indicates an average total increase in drawdown of about 5.3 feet. The map made for 20 years beyond 1994 indicates an average total increase in drawdown of about 7.3 feet.

  3. Hydrogeology and Potentiometric Surface of the Dublin and Midville Aquifer Systems in Richmond County, Georgia, January 2007

    USGS Publications Warehouse

    Williams, Lester J.

    2007-01-01

    INTRODUCTION The Dublin and Midville aquifer systems are part of the Cretaceous aquifer system that underlies most of Richmond County, Georgia (Gorday, 1985; Falls and others, 1997). The Cretaceous aquifer system is the second most productive aquifer in Georgia and is a major source of water in the region. About 220 million gallons per day (Mgal/d) of water was withdrawn from the Cretaceous aquifer system during 2000 in Georgia (Fanning, 2003). The Augusta-Richmond County Water System is the largest public water supplier in the county and withdrew 13 Mgal/d of ground water during 2000; withdrawals decreased from 2001 to 2005. The towns of Hephzibah and Blythe withdrew 0.4 and 0.03 Mgal/d, respectively. Industrial ground-water withdrawals are concentrated along the Savannah River and totaled 2.89 Mgal/d. To monitor seasonal and long-term water-level fluctuations and trends in the aquifers, the U.S. Geological Survey (USGS) - in cooperation with Augusta Utilities - maintains a countywide network of about 100 water-level monitoring wells in various aquifers, including a new continuous monitoring site (well 30AA33) and two existing USGS-Georgia Environmental Protection Division network sites (wells 29AA09 and 30AA04). Data compiled during this study were used to better define the hydrogeologic units and to construct an updated potentiometric-surface map for the area, which is used to better understand ground-water movement in the Cretaceous aquifer system. In addition, the potentiometric surface and related water-level data can be used for water-resource planning and to update ground-water flow models for the region (Clarke and West, 1997; Cherry, 2006).

  4. An innovative approach for very large landslide dynamic and hydrogeological triggering study by inverse modeling (Grand Ilet landslide, Reunion Island)

    NASA Astrophysics Data System (ADS)

    Belle, P.; Aunay, B.; Join, J.-L.; Bernardie, S.

    2012-04-01

    Landslide control mechanisms study and displacements modeling interest the scientific community since several decades, with a common objective: landslides prediction for humans and infrastructures protection. However many data acquisition, like pore water pressure or mechanical properties, are necessary for determinist model construction. It could be extremely complex for very large landslides in extreme climatic conditions. An innovative modeling method is proposed for very large landslide functioning characterization using the primary data rainfall and displacement. Here we study two very large landslides (? 450 Mm3) in a humid tropical climate (Salazie cirque, Reunion Island). We use an inverse modeling tool basing on a global approach, with Gaussian-exponential transfer functions. Transfer functions between the rainfall input signal and the velocity output signal (permanent GPS daily data)are determinated. Because of the gap displacement data, the hydrologic cycles 2010 and 2011 is selected for the calibration of transfer functions. Afterwards, we model the landslide velocity from rainfall signal since 2004 to 2011. In the case of Grand Ilet landslide, we study relations between transfer functions characteristics and the coupling between the displacements and the hydrogeological functioning. For cumulated displacements, final difference between simulations and observations for 7 years modeling is smaller than 5 %. Seasonal landslides velocity variations are accurately modeled during a period of 7 years. Bimodal transfer functions, with dissociation between rapid and slow impulse responses, are particularly effective for reproducing the recorded displacements. In particular, rapid response permits to model velocity increases after cyclonic events. In case of Grand Ilet landslide, transfer functions characteristics are strongly correlated with the landslide aquifer functioning. Indeed, influence times of rapid and slow responses are reliable with a double porosity effect. Rapid response is correlated with preferential flows in fractures network, whereas slow response is correlated with slow piezometric recharge of the porous medium. These results show that global approach is significant for very large landslide study, in Reunion Island context. Present method could then become a promising process for other very large landslide studies.

  5. Characterization of unsaturated zone hydrogeologic units using matrix properties and depositional history in a complex volcanic environment